WO1998006340A1

WO1998006340A1 - Method and apparatus for preventing adhesion and colonization of bacteria in medical devices

Info

Publication number: WO1998006340A1
Application number: PCT/US1996/013174
Authority: WO
Inventors: Marvin A. Prescott
Original assignee: Prescott Marvin A
Priority date: 1995-06-07
Filing date: 1996-08-14
Publication date: 1998-02-19
Also published as: AU6846296A

Abstract

By compounding photochemicals in the material used to form, for example, air and water supply lines (6) for use in dental appliances (4), and activating these photochemicals through the use of laser beams, the adherence and colonization of bacteria within the water and air supply lines (6) can be prevented and eliminated. In addition to activating the photochemicals, the laser beams, which are preferably low power laser beams having a predetermined wavelength, can be utilized to biostimulate tissue surrounding locations where, for example, catheters (40) and other implantable medical devices are inserted into the patient's body, thereby stimulating the patient's immune system to suppress the growth of bacteria therein. By forming the catheters (40) and other implantable medical devices with a photochemical coating or compounding the photochemicals with the material of the devices themselves and activating the photochemicals through the use of laser beam energy, the adherence of colonization of bacteria to the medical devices can be reduced and eliminated.

Description

METHOD AND APPARATUS FOR PREVENTING

ADHESION AND COLONIZATION OF BACTERIA

IN MEDICAL DEVICES

Field of the Invention

The present invention is directed to the prevention of adhesion and colonization of bacteria in medical devices. More particularly, the present invention is directed to a method and apparatus using low power laser beam energy to control the adhesion and colonization of bacteria in medical devices and other circumstances.

BACKGROUND OF THE INVENTION

Infections caused by the adhesion and colonization of bacteria in medical devices are well documented. The dental profession has experienced numerous instances where infections were spread amongst groups of patients due to infected health care staff and infected instruments. The Centers for Disease Control and Prevention as well as the Occupational Safety and Health Administration have both issued guidelines making dentistry much safer today than it has ever been. However, the dental profession is constantly concerned about controlling the spread of infection through the use of dental instruments such as air and water sprays that are used with each patient. Of primary concern is the reduction of microbial contamination in dental unit air and water lines which are used with the majority of dental instruments that are utilized in a standard treatment regimen for dental patients. Indeed, water line contamination represents a major health care concern not only for the dental industry, but also for the medical industry and the general community at large. One of the major concerns regarding the water lines used in the medical and dental professions are development of biofilms or bacteria colonies within the water lines.

Similarly, air purification to prevent the spread of airborne bacteria is also a major concern for the medical and dental professions. As every patient who has ever sat in the dental chair is aware, a dentist regularly uses a supply of compressed air to dry portions of the oral cavity as well as to operate the instruments needed to provide dental treatment. While the use of microbial filters and other antibacterial devices are recommended, significant concerns remain regarding the spread of bacteria due to the build up of biofilms in the compressed air supply in medical treatments.

At the present time, there is no known effective solution to the problem of bacterial adhesion and colonization in medical/dental air and water lines while they are in use. Pathogenic bacteria such as legionella and pseudomonas are routinely cultured from the air and water lines used in medical and dental equipment. Further, infections associated with indwelling medical devices such as intravenous catheters, urinary catheters, central nervous system shunts, pacemaker leads, joint prostheses, as well as vascular grafts present a more serious problem as the number of patients at risk essentially comprises each and every patient who has an indwelling medical device. The presence of an indwelling foreign body predisposes the patient to, and greatly complicates the eradication of, bacterial infections.

As an example of the number of indwelling medical devices found in patients, it has been reported that in 1987, on the order of 140,000 hip prostheses and 1 15,000 other joint prostheses were inserted in the United

States alone. These figures do not include each medical patient who was admitted to a hospital or other medical facility and provided with an intravenous catheter or other temporary indwelling medical device. Each of these patients is subject to the development of infection and disease due to the adhesion and colonization of bacteria associated with the medical devices which are utilized in their treatment.

Additional groups of patients at high risk for bacterial infection include organ transplant recipients, dialysis recipients, and patients who have undergone colostomy operations. The nature of these procedures, and the amount of catheterization involved, inherently make such patients prone to bacterial infection.

While research has suggested which bacteria are usually involved in infections associated with medical devices, e.g., Staphylococcus epidermidis and Staphylococcus aureus, and the mechanism by which even non-pathogenic bacteria such as Staphylococcus epidermidis become pathogenic in the presence of "foreign bodies" (i.e., medical devices), at present there is no effective method or apparatus to prevent these life- threatening infections by preventing the adherence and colonization of such bacteria.

Studies have suggested that low power laser light can immobilize bacteria or, through the use of additional mechanisms, can actually assist in overcoming invading organisms. For example, it has been found that through photochemicals which are activated by photon energy, the photochemicals produce singlet oxygen molecules and hydroxyl free radicals. Research has suggested that the free radicals are instrumental in killing bacteria. Other studies have suggested that laser biostimulation enhances the ability of lymphocytes to bind pathogens. Such laser biostimulation augments the ability of the body's immune system to overcome invading organisms. Studies have further shown that pathogenic organisms such as the previously mentioned Staphylococcus aureus, and Escherichia coli are inhibited by laser beam energy.

Studies have also been done which indicate the direct effects of low power laser beam energy on the cell membrane of the bacteria itself, i.e. at higher powers there have been found to be abiotic effects. These effects may be a wavelength specific effect on the lipopolysaccharides in the bacterial cell wall.

In addition, numerous scientists and watchdog groups, such as the Centers for Disease Control, have been increasingly expressing concern regarding the evolution of antibiotic resistant bacteria. This has led to the resurgence of many illnesses which were previously thought to have been eradicated. For example, approximately twenty percent (20%) of tuberculosis microbes resist isoniazid, which is the preferred treatment for TB. Similarly, it was reported in Newsweek magazine that gonorrhea microbes are found to resist treatment using penicillin, while more than half the strains of Staphylococcus aureus, which causes blood poisoning, resist virtually every treatment but vancomycin. To make matters worse, it has been found that the enterococcus microbe can transfer vancomycin resistance to Staphylococcus aureus! Enterococcus and Staphylococcus aureus can come into contact on a daily basis, for example, on bandages, hospital sheets, and numerous other locations within a hospital setting.

Accordingly, there is a need in the medical and dental community for a device and a method for controlling the spread of bacteria and infections from medical devices. Additionally, there is a need for accomplishing such control without the use of traditional antibacterial agents such as pharmaceuticals to which the bacteria can become resistant. In addition, given the proliferation of the problem with bacterial infection and the number of locations where the problem can occur, the method and apparatus for controlling the spread must be relatively low cost, efficient, and preferably portable. SUMMARY OF THE INVENTION

The present invention overcomes the problems associated with biofilms in medical and dental devices by providing a method and apparatus for preventing the adhesion and colonization of bacteria. More specifically, the present invention solves the problems associated with the adhesion and colonization of bacteria in dental and medical air and water lines, a problem which is prevalent in the medical and dental industry. The present invention also provides for a relatively low cost, efficient and portable device and method for treating and preventing bacterial adhesion and colonization associated with indwelling medical devices without the use of traditional antibacterial treatments.

The present invention achieves the above and other objectives of the present invention through a preferred embodiment in which photochemicals are compounded in small amounts into material which is utilized in the manufacture of tubing and connectors for medical and dental water lines and other devices. The photochemicals can be activated by a specific wavelength and amount of laser beam energy. A source of laser beam energy is provided along a length of the tubing which supplies the air and water to the medical and dental instruments and the laser beam energy is emitted on a timed periodic schedule through the use of a power supply and control device. The lasers can be time-controlled in accordance with known research data on the timing of bacterial adhesion and colonization in air and water lines and indwelling medical devices in order to have the laser beam energy administered at intervals of greatest potential for bacterial adhesion and colonization.

In another embodiment of the present invention, a method and apparatus are provided for stimulating an area surrounding a catheter device which is inserted into a patient. The catheter itself may be formed of materials which include a photochemical compounded with the material forming the catheter. Alternatively, the catheter may be provided with a hydrogel coating having photochemicals incorporated therein on portions of the walls of the catheter. The photochemicals are activated through the application of laser beam energy in order to prevent adherence and colonization of bacteria on the catheter needle and hub assembly as well as a short section of the catheter tubing as it attaches to the hub. The laser beam energy can also biostimulate the area surrounding the insertion point of the catheter into the patient's body. Such an arrangement assists in biostimulating the patient's immune system to fight the growth of bacteria at the site of the indwelling medical device, as well as eliminating any bacteria which may accumulate at the entry point on the catheter itself.

In another preferred embodiment of the present invention, vascular grafts which are made of, for example, Gore-Tex (polytetra fluoroethylene) can be manufactured with photochemicals which may be compounded directly into the material used to make the vascular graft, or may be incorporated in a hydrogel coating which is covalently bonded to the vascular graft material. In the case of superficial vessels which incorporate the vascular graft, the photochemicals may be activated by the application of a laser bandage affixed to the skin over the graft on the patient's body.

Alternatively, in the case of deeper vessels, the laser beam energy may be delivered to the graft through the use of optical fibers which are coupled to the laser bandage, which optical fibers are temporarily implanted at the surgical site in a manner similar to suture placement. As with the previously discussed embodiments, a programmable source of laser beam energy coupled to the fibers permits the fibers to transmit the laser light along their length to the vascular graft which is incorporated in the deeper laying vessel. By varying the length of the fibers, it is possible to provide for the application of the laser beam energy not only to the vascular graft, but also along the length of the incision and treatment area surrounding the graft location. In each situation, the light activated photochemicals would assist in killing any existing bacteria and preventing subsequent bacterial adhesion and colonization on the graft. In addition to the application of the laser beam energy from the bandage to the graft by direct application as well as through the use of optical fibers (which can additionally be provided with abrasions along the length thereof to allow light to leak into the surrounding tissue as it travels therethrough), the present invention simultaneously allows for the application for the laser beam energy to the tissue surrounding the vascular grafts. This enables biostimulation of the tissue surrounding the graft in order to stimulate the immune system in the immediate area of the graft. The known wound healing affects of biostimulation using low powered lasers would then speed the healing of the graft and the surgical site and possibly increase the success rate of the graft procedure itself.

The above and other embodiments and features of the present invention will be better understood through a reading of the detailed description of the present invention when taken in conjunction with the drawings. It should be understood that the following descriptions and drawings are in no way intended to limit the present invention which is best defined by the claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 shows a perspective view of a dental unit incorporating the present invention.

FIGURE 2 is a cross-sectional view of the air and water supply line taken along the lines 2-2 in FIGURE 1 .

FIGURE 3 illustrates a cross-sectional view of the air and water supply line seen in FIGURE 2 taken along the lines 3-3. FIGURE 4 is a cross-sectional view of an alternative air and water supply line taken along the lines 4-4 in FIGURE 1.

FIGURE 5 is a schematic illustration of a laser diode array in accordance with an embodiment of the present invention. FIGURE 6 is a cut away schematic diagram of an air and water supply tube connecting to the dental unit seen in FIGURE 1 taken along the lines 6-6 of FIGURE 1.

FIGURE 7 is a perspective view showing in an alternative application of the method and apparatus of the present invention on a patient's arm. FIGURE 8 is an exploded view of a catheter device incorporating an embodiment of the present invention.

FIGURE 9 is a cut away top view of the catheter device incorporating the present invention illustrated in FIGURE 8 taken along the lines 9-9. FIGURE 10 is a cut away side view of an alternative embodiment of the present invention for use of vascular graft treatments.

FIGURE 1 1 is a cut away side view of an alternative embodiment of the device seen in FIGURE 10.

FIGURE 12 is a magnified cut away side view of the coupling mechanism seen in FIGURE 1.

FIGURE 13 is a partial cut away side view of an alternative embodiment of the present invention for use in a dental unit having a retractable air and water supply line mechanism.

FIGURE 14 is a partial schematic diagram illustrating an alternative system for supplying laser beams for use with the embodiments of the present invention illustrated in FIGURES 1-13.

FIGURE 15 is a partial cross-sectional view of an integral laser array bandage for use with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGURES 1-15 illustrate the preferred embodiments of the present invention. In the following discussion of the presently preferred embodiments, like reference numerals refer to like elements. Further, it should be understood that the following discussion is not to be considered in a limiting sense. Rather, it is to be understood that the following discussion taken in conjunction with the drawings illustrate the presently preferred embodiments of the present invention but that the invention is in no way limited to the embodiments described below and shown in the drawings. It is to be understood that numerous modifications, additions and/or substitutions can be made to the preferred embodiments without departing from the spirit and scope of the present invention.

Referring to FIGURES 1-6, a first preferred embodiment of the present invention is illustrated. More particularly, a dental cabinet 1 which is typically found in a dental office includes an exterior wall 2 and a work tray 3 which serves to hold a supply of dental tools 4. The dental tools are generally coupled to air and water supply tubes or hoses 6 by way of a coupling 5. An air and water supply hose 6 supplies the dental tools 4 with air and water under pressure. The air supply is typically used to drive the dental tools. As discussed above, the prevention of bacterial adhesion and colonization in the air and water supply is a concern of the present invention.

The cross-sectional view of an air and water supply hose 6 of the present invention as seen in FIGURE 2 reveals an outer casing 10 which can comprise an opaque shrink tube jacket which provides a protective outer coating to the inner tube structure 12. Alternatively, the outer coating 10 may comprise a separately extruded tubular structure shaped to accommodate the inner tube structure 12 and be formed of an opaque material while the inner tube structure could remain optically clear. Also, it is possible to coat the outer surface of the inner tube structure 12 with an opaque coating through dyeing, painting or other similar process.

The inner structure 12 of the tube may be formed using an optically clear tubing such as, for example, optically-clear silicone, polyurethane, polyvinylchloride, rubber, or other suitable polymer or structural compound.

In the preferred embodiment, a polyvinylchloride (PVC) tubing having a hardness approximately between 65 and 80 Shore A and which extrudes at 350 degrees Fahrenheit is preferred. Polyether based polyurethane having a hardness approximately between 80 and 90 Shore A which extrudes at approximately 400 degrees Fahrenheit can also be used with the present invention. While optically clear material is preferred, provided the material can conduct light from a laser source discussed in more detail hereinbelow, it is not necessary for the material to be optically clear. According to a preferred embodiment of the present invention, the inner tubing structure 12 is compounded with photochemicals (described in more detail below) which are capable of being activated by specific wavelengths of low power laser light.

The air and water supply tube 6 includes a pair of large tubular bores 14 which provide for the supply and exhaustion of compressed air to and from the dental tools 4. The tube 6 also includes a pair of smaller tubular bores 6 which provide for a combined supply of air and water to the dental tools 4. Disposed within each of the larger and smaller tubular bores 14, 16, respectively, an optional photochemical lining 15 may be provided on the side wall surfaces of the tube bores. The photochemical lining is comprised of a thin, optically clear insert made from the same material as the inner structure 12 of the tube 6 but which is compounded with the photochemicals which are activated by the specific wavelengths and power supplied by a laser beam.

Alternatively, element 15 may represent a hydrogel coating bonded to the inner wall surface of the tubular bores 14, 16. The hydrogel coating may have photochemicals incorporated therein which can be activated by specific wavelengths and power supplied from a laser beam.

The extruding process to produce the tubular structure 6 seen in FIGURES 2 and 3 involves extruding the material forming the inner structure 12 of hose 6 through an appropriate die in order to produce the structure seen in the FIGURE. By extruding at a temperature below 400° Fahrenheit, there is no risk of damaging the photochemicals compounded with either in the tubular structure 12 itself or within the linings 15 provided in the tubular bores 14, 16.

Referring to FIGURE 2, a flexible circuit board 20 is preferably disposed within an interior cavity 18 which remains after the extruding process inside the tubular structure 12. The flexible circuit board 20 has disposed thereon a plurality of electrically linked laser diodes 28 as seen in FIGURE 5. The laser diodes are preferably vertical cavity surface emitting lasers or "VCSELs." VCSELs are semiconductor lasers which emit a collimated beam normal to the surface of the semiconductor substrate. The semiconductor typically comprises aluminum arsenide (AIAs) or gallium arsenide (GaAs), or some combination thereof. Each VCSEL has a self- contained, high-reflectivity mirror structure forming a cavity to produce the collimated beam. Due to the ability of VCSELs to produce the collimated beam, it is unnecessary to provide additional collimating lenses to focus the beam. It is possible, however, to provide each or selected VCSELs with a lens structure to focus or spread the beam, as desired. While it would be possible to utilize standard laser diodes in place of the VCSELs in the present invention, the inventor has found that VCSELs represent the preferred laser beam source over conventional laser diodes due to the reduced size and power consumption of the VCSELs. A typical VCSEL may be on the order of 300 micrometers long, and have an operational power threshold below one milliamp and consume very little power compared with conventional laser diodes. This enables numerous VCSELs to be powered from a single, portable power source.

In addition, VCSELs have the capability to produce light in the infrared, visible and ultra-violet spectrums, thus allowing for additional applications for the device for the present invention, as will be discussed in more detail below. For the purposes of the discussion, it should be understood that where the terms "laser" or "lasers" are used, the preferred embodiment uses VCSELs but that conventional laser diodes are also applicable. The opaque coating 10 which is disposed about the tube structure 6 shown in FIGURE 2, and in the tube structure 24 seen in FIGURE 4, provides for retinal protection from the laser beams generated by the VCSELs.

FIGURE 4 illustrates a cross-sectional view of an alternative form of the air/water supply lines shown in FIGURE 4. The tubing in FIGURE 4, which is generally applicable for use with an air/water syringe found in most dental offices, includes two tubular bores 26 which provide the necessary air and water supply to the instrument. An outer casing 22 is shrink wrapped about the inner structural member 24 which forms the tubular bores 26. An identical photochemical compounded lining member

15 (or hydrogel coating incorporating photochemicals) can be provided within the tubular bores 26. The flexible laser strip 20 may be disposed between the tubular bores 26. The material 24 is preferably formed of an optically clear silicone, polyurethane, or other material similar to the inner tubular material 12 to allow laser beams generated from the VCSELs disposed on the flexible circuit board 20 to be transmitted through the material 24 to the chemically treated linings 15, if such linings are present, or to the surrounding material 24 to activate photochemicals compounded therein. As with the hose 6 shown in FIGURE 2, the air and water supply line in FIGURE 4 can have an inner cavity 19 defined by the outer peripheral edge 1 7 of the tubular bore 26. In this fashion, the flexible board 20 could be inserted into the cavity 19.

The flexible circuit board 20 shown in, e.g., FIGURES 2, 4 and 5, is preferably a flexible polymer substrate such as that manufactured by Poly-

Flex Circuits, Inc. which uses an additive polymer circuit (APC) technology. The APC technology forms circuit patterns by a printing technique using a conductive ink to which are then fastened circuit elements using an appropriate adhesive. The final assembly can be folded, rolled and shaped as desired . This technology is cost effective and eliminates the need for the chemical washing typically required in the manufacture of standard printed circuit boards. The VCSELs may be dispersed along the length of the board and interconnected using the conductive ink. The board 20 may be disposed within a coiled tubing structure such as 6 as seen in FIGURE 1 and is preferably flexible enough to allow a dentist or other individual such as a dental hygienist to manipulate the instrument in the same manner as with the tubing devices of the prior art which do not incorporate the present invention.

Alternatively, the flexible circuit board 20 may be made using a flexible, non-conductive material such as Kapton which is available from

Dupont. Flexible circuit boards also may be made of Ultem, a flexible, non- conductive material available through GE Corporation. Such circuit boards incorporate flexible electrical connectors which are used to interconnect arrays of VCSELs on the flexible circuit board 20. Control for the device seen in FIGURES 1 -5 is shown in FIGURE 6.

More specifically as seen in FIGURE 6, the tube structure 6 enters the side wall 2 of the cabinet 1 . The tube structure is essentially peeled in a banana-like fashion to expose the flexible circuit board 20 and to separate the air and water supply tubes 26. For purposes of illustration, the dual tubular bore structure as seen in FIGURE 4 is illustrated in FIGURE 6. Of course, those skilled in the art would readily appreciate that the quad- tubular bore structure as seen in FIGURE 2 can also be separated in the same fashion. As seen in FIGURE 6, one of the tubular bores is led to a standard water supply 30 while the other tubular bore 26 is led to the standard air supply device 34. The flexible circuit board 20 is provided to a power source and control unit 32. The power source and control unit 32 provides a source of power for energizing the vertical cavity surface emitting lasers which are disposed upon the flexible circuit board 20. These lasers begin lasing when a sufficient amount of the current is supplied thereto. The control device additionally provides a timing function to time such energization, preferably to coincide with known adhesion timetables of bacteria established by existing research. Of course, it should be understood that the power supply and control unit 32 can control the lasers to operate on a periodic basis, e.g., on an hourly, daily, or even permanent basis.

FIGURE 1 2 illustrates additional details of the coupling member 5 seen in FIGURE 1 . Specifically, as seen in the cut away side view shown in FIGURE 1 2, a coupling insert 26, which is preferably a nonconductive insert having the same size tubular bores 26' and 26' as with the tube 22 which extends into the coupling 5 a predetermined distance, is inserted into the end of the coupling and the flexible circuit board 20 is allowed to exit through the insert 27 to terminate flush with an upper surface of the insert 27. The coupling insert 27, which is found in dental tool coupling devices, is provided with the bore to receive the flexible circuit board 20. Alternatively, the circuit board 20 can be sized to terminate inside the insert 27 by eliminating the passage for the circuit board 20 through the insert 27. A recess 29 is found in the upper end of the coupling 5 to receive the bottom portion of the dental tools 4.

In operation, the preferred embodiment of the present invention as illustrated in FIGURES 1 -6 and 12 prevents the adhesion and colonization of bacteria in medical and dental air and water lines. Specifically, the photochemicals which are compounded in small amounts with the material of the tubing, and which may also be compounded with the coupling insert 27, as seen in FIGURE 12 are activated by the periodic emission of laser light from the lasers disposed on the flexible circuit board 20.

The chemicals which are compounded into the tubing material can be selected so that they are activated by laser light having a wavelength which is approximately between 700 and 800 nanometers, with activation at approximately 750 nanometers being preferred. Such photochemicals include, for example, mesoverdin which is the preferred photochemical, with napthalocyanines also being suitable for use with the present invention. Mesoverdin is a porphyrin-ϋke tetrapyrrole described in, e.g., H.

Fischer and J. Ebersberger, Justus Liebigs Ann. Che. 509 19(1934). See also, H. Groschel, Ph.D. Dissertation, Technische Universitat, Braunschweig, West Germany (1964). The following mesoverdin methyl ester isomers are contemplated for use with the present invention (free acids may also be used):

By compounding the photochemical into the tubing material, and activating the photochemical through the application of laser light having the appropriate wavelength, the photochemical is activated to slowly release singlet oxygen and hydroxyl free radicals to prevent the adhesion and colonization of bacteria within the tubing, and also to kill any bacteria which are present within the tubing material. The compounding process can be accomplished in numerous ways.

In the presently preferred embodiment, the photochemicals are mixed with the material used to form the inner tubing structure 12 prior to extrusion. Thus, after extrusion (which is preferably accomplished at a temperature below 400 degrees Fahrenheit to avoid harming the photochemicals), the photochemicals are dispersed throughout the tubing structure.

Alternatively, the photochemicals may be applied to the outer surfaces of the inner tubing structure 12, including the bores 14, 1 6. In this fashion, those surfaces of the tube 6 which are most susceptible to bacterial adherence and colonization would be treated with the photochemicals. The activation of such photochemicals would thus prevent such an occurrence.

Alternatively, a hydrogel coating can be bound to the interior surface of the tubular bores 14, 1 6 and 26. The hydrogel coating can have photochemicals incorporated therein which can then be activated by the low power lasers which operate at the desired wavelength. The beams can produce any desired amount of energy, e.g., from one milliwatt or less up to ten milliwatts or more. Approximately 3-5 milliwatts represents a preferred operating range that affords sufficient power for the present invention to activate the photochemicals. In addition, this power operating level provides an optimum power output for laser treatments which rely upon a battery operated power supply and control device as discussed in more detail hereinbelow.

As an alternative to the preferred VCSELs, it is possible to utilize lasers which produce beams of light in the ultraviolet spectrum. The light in this spectrum is known to have a direct antibiotic effect without the use of photochemicals. Such light would be particularly useful on medical devices and equipment which are not easily susceptible to antibacterial treatment or which suffer extreme wear and tear through traditional sterilization techniques such as autoclaving.

In addition to compounding the preferred Mesoverdin photochemical and the alternative Napthalocyanines with the tubing and other material as discussed above, the use of the hydrogel coating allows for the photochemicals to be incorporated in the hydrogel coating. The hydrogel coating can be covalently bound to numerous medical device surfaces which are formed of polymers such as the tubing described above, and the photochemical bacteriocidal and bacteriostatic agents can then be activated by selected wavelengths of laser beam energy. In addition, depending upon the location of the application of the hydrogel coating, the coating can assist in the insertion of catheters into vascular or urogenital locations.

Furthermore, by providing a hydrogel coating, for example, on the insert 15 within the tubular bores 14, 16 and 26 as seen in FIGURES 2 and 4, the change in the surface property reduces bacterial adherence initially and during the lifetime of the device. By further supplementing the hydrogel coating which is bonded to the polymer lining of the insert 15 with the photochemicals, and activating the photochemicals using the laser beam energy, an additional level of protection is afforded in preventing the adherence and colonization of bacteria within the tubular bores 14, 16 and 26. This same procedure can be used to activate photochemicals incorporated into a hydrogel coating or compounded directly with the material of various implanted and inserted medical devices as discussed above.

Turning to FIGURE 7, a catheter assembly 40 is shown inserted into a patient's arm. A feed line 42 is fed to a removable coupling 44 which removably connects to a coupling receptacle 42 that is connected to the actual catheter needle 58 which is inserted into the patient's arm. A power supply cable 48 extends from the power supply and control unit 50 to a laser array bandage 54. In the FIGURE, the power supply and control unit 50, which operates in a substantially identical fashion to the power supply and control unit of the above-discussed embodiment, is affixed to the patient's arm using a strap 56. An additional strap 52 is used to hold the catheter assembly 46 in place during the patient's treatment. The lasers 54 are embedded within the strap 52 which comprises, for example, a latex or silicone flexible sheet. The lasers may be disposed on a flexible circuit board similar to 20 described above. The lasers 54 are exposed on one side of the bandage 52 such that light generated thereby my reach the surface of the patient's skin. In the preferred embodiment, the power supply and control unit 50 can be formed integral with the laser array 54 in the bandage 52 as illustrated in FIGURE 1 5, to form an integral laser array bandage 51 . Referring to FIGURE 15, the integral laser array bandage 51 can be affixed directly over the catheter hub assembly 40 adjacent the location where the needle 58 enters the patient's arm. The bandage 51 may be held in place using a velcro strap or suitable medical adhesive.

The integral laser bandage 51 includes an outer covering identical to the material used to form the bandage 52 seen in FIGURE 7 and thus the reference numeral 52 is used to identify the outer cover. A flexible circuit board 59 as described above is imbedded within the bandage 51 . The circuit board 59 has VCSELs 54 bonded thereto. For illustration purposes, an electrical link 55 is shown between the VCSELs, but one skilled in the art will understand that such a link would be formed on the flexible circuit board 59. The bandage 51 is provided with a series of openings 57 over each of the VCSELs 54 to enable the laser beams generated by the VCSELs to exit the bandage 52. Optically clear covers 60 may be provided over the openings 57. The bandage 51 incorporates a flexible, thin-film plastic battery 53 manufactured by Bellcore. Like the circuit boards 20, the battery 53, which is based on lithium-ion technology, is also capable of being bent and formed. Due to its incorporation of a polymer capable of carrying both electrode particles and liquid electrolyte (which is trapped in the polymer matrix) there is no danger of battery leakage. The battery 53 is electrically connected to the flexible circuit board 59.

The emission of laser light from the lasers 54 to the patient's skin serves a dual purpose. First, it allows for the biostimulation of the tissues surrounding the area in which the catheter needle is inserted into the patient's arm. This biostimulation stimulates the immune system's ability to overcome invading organisms by activating lymphocytes and increasing their abilities to bond pathogens. In addition, either the catheter needle 58 or the coupling receptacle 46 and coupling member 44, or all three, can have photochemicals compounded therein or bonded thereto through the use of the above-described hydrogel coating. In this fashion, the strap 52 would be sized so as to overlay the entire catheter assembly 40 at the location where the catheter assembly is inserted into the patient's arm. In this fashion, in addition to the laser beams causing the biostimulation of the patient's arm, the laser beams can also be directly applied to the catheter assembly including the needle 58 and the coupling units 44, 46, thereby activating the photochemicals disposed therein to combat the adhesion and colonization of bacteria.

As seen in FIGURE 8, a catheter 60 may include a catheter body 62 along which are disposed thin strips of laser diodes 64. Alternatively, fiber optic rods or strands 64 may be imbedded within the catheter body 62 and run along the length thereof. The fiber optic strands 64 can be scored to allow light to leak therefrom as it travels through the strands 62. Electrical or fiber optic connections 66 can be provided at a distal end of the laser arrays or fiber optic strands 64. Alternatively, since the VCSELs are sized on the order of microns, such VCSELs could be disposed at the distal end of the catheter body 62.

In this embodiment, the catheter body 62 would be compounded with photochemicals which are activated by the light produced from the lasers disposed in the arrays 64, or leaked through abrasions formed in strands 64 (which would preferably be made of polymethylmethacrylate or

PMMA which is a plastic fiber with a fluorinated polymer cladding) which carry laser light from the distal end of the catheter body 62. By activating the photochemicals, the colonization and adherence of bacteria within the catheter probe can be prevented. The proximal end 63 of the catheter 60 is seen in FIGURE 7 as a point. Of course, one skilled in the art would readily understand that the proximal end 63 would be sized so as to be easily insertable into or removable from, for example, a patient's body, or a catheter sheath which is inserted into a patient's body.

As seen in FIGURE 9, which is a cross-section view taken along the lines 9-9 of FIGURE 8, the catheter 60 may include an inner lining 68 which is coaxial with the body 62. The inner lining may be, for example, the same as insert 1 5 illustrated in FIGURES 1 -6. Alternatively, as discussed above, the inner lining 68 may comprise a hydrogel coating which is bonded to the inner wall surface of the body 62 and have, incorporated therein, photochemicals which are activated by the selective wavelength of the light generated from lasers disposed on flexible laser array strips or fiber optic strands 64 which are incorporated into the body 62 of the catheter 60. Thus, the laser light would pass through the body 62 of the catheter 60 and activate the photochemical compounded with the lining or coating 68. Of course, it should be understood that the body 62 of the catheter 60 is preferably formed of an optically clear material to allow the laser light to pass therethrough. The entire outer surface of the body 62 may be provided with an opaque shrink wrap to avoid any possibility of retinal damage due to leakage of laser light, or may be provided with an opaque coating in the manner described above in connection with the first embodiment.

An alternative construction to that shown in FIGURE 9 is to layer the laser array strips 64 (which may be formed in a fashion identical to the flexible circuit board discussed in conjunction with FIGURES 1 -6 above), on the outside of the catheter body 62, and to provide a shrink tubing jacket about the catheter and laser array strips 64. This arrangement will hold the strips in place on the catheter body 62. Also, if the lasers are focused inward, the shrink tubing jacket can be formed of opaque material to prevent laser light leakage, thus serving a dual purpose of protecting against retinal damage while holding the laser array strips in place on the outer surface of the catheter 60. It should be understood that this same arrangement will work with fiber optic strands in place of flexible laser strips. FIGURES 10 and 1 1 illustrate another preferred embodiment of the present invention. As seen in FIGURE 10, a laser bandage 70 has imbedded therein a plurality of lasers 71 . The bandage 70 is placed upon the outer dermal layer 72 in a position substantially radially outward from vein 76 which is disposed within the inner dermal layers 74. A vascular graft 78, which may be made of Gore-tex (polytetra fluoroethylene) and which typically has a high rate of bacterial adhesion and colonization, can be compounded with photochemicals or have a hydrogel coating incorporating photochemicals therein. In the case of superficial vascular grafts, such as that illustrated in FIGURE 10, the laser 71 can be powered through a power source and control unit 72 which is substantially identical to that discussed above in conjunction with the first preferred embodiment, to produce the laser beams which penetrate through the dermal layer 72, thus activating the photochemicals compounded into the vascular graft 78. In the alternative, in situations where the vascular graft 78 is disposed too deep to allow the laser beam energy to penetrate through the dermal layer 72, the lasers 71 can be provided with optical fibers 80 which extend from the lasers 71 through the dermal layers 72, 74 and related tissue to conduct the laser beam to the vascular graft 78. As can be seen in FIGURE 1 1 , the optical fibers 80, which are generally formed of an optically clear glass, polymethylmethacrylate (PMMA) or other suitable material, are imbedded through the dermal layers 72, 74 and related tissue. It should also be noted that the optical fibers 80 are not connected with all of the lasers 71 on the bandage 70. There are several reasons for this structure. Since a typical VCSELs may be on the order of 300 micrometers long, the optical fibers 80 can be as small as, for example, a typical surgical suture. By inserting the optical fibers along the location of the incision made to repair the vein 76, the optical fibers 80 can remain in the patient after the incision is closed. Due to their small size, scarring will generally not occur, or would be no more apparent than a typical suture scar. When sufficient treatment has been provided to the patient, the optical fibers 80 can be removed much like a suture is removed from a patient. By not coupling the optical fibers 80 to selected VCSELs 71 , those VCSELs can participate in the biostimulation of the tissue surrounding the incision made to repair the vein 76. In this fashion, the biostimulative wound healing affects of low power lasers, which are known, can assist in decreasing the amount of time necessary for healing of the surgical wound and reduce the possibility of infection from the surgical process itself by biostimulating the surrounding tissue. Additionally, the use of the PMMA fiber material allows the rods to be abraded (preferably every .01 inches) so that light leaks along the length of the fibers 80, thus biostimulating the tissue surrounding the fibers in the area of the vascular graft 78 and the incision where the graft was inserted. In addition, by varying the length of the fibers 80 so that some fibers do not reach the graft 78, the laser light will be applied directly to the inner dermal layers 74. This will stimulate the body's natural healing of the wound as discussed above and reduce or eliminate potential infections in the surrounding tissue. Another alternative embodiment of the present invention is seen in

FIGURE 13. FIGURE 13 illustrates a typical water and air tube storage unit 90 disposed within a dental unit 1 such as that seen in FIGURE 1 . A plurality of separate storage bins 92 are provided within the storage unit 90 to house the separate combined air and water supply lines for use with different dental instruments. A plurality of coiled hoses 94 are disposed within each of the storage bins 92. A coupling 96 is provided to couple the air and water supply lines to a main connection which feeds back to the main supply of air and water to the storage bins 92. It is possible to dispose a plurality of laser arrays 100 within the side walls 98 of the storage unit 90 and to radiate the entire interior of the separate storage bins 92 when the hoses are disposed therein.

By providing for the compounding of the photochemicals into the material of the tubing 94, the application of the laser beam within the interior of the storage bins 92 results in the activation of the photochemical disposed therein, thereby preventing the adhesion and colonization of bacteria within the air and water supply lines. The lasers 100 produce the laser light which travels in the direction 102 seen by the arrows in FIGURE 1 3. While only several arrows 102 are illustrated, it should be understood that each of the lasers 100 produce laser beams which travel into the interior of the compartments 92. In this fashion, the entire surface area of the hoses 94 disposed within the compartments 92 are subjected to laser beam irradiation causing the activation of the photochemicals disposed therein. As with the above discussed embodiments, the lasers 100 can be controlled through a power source and control unit which provides for a continuous or timed irradiation of tubes disposed therein with both infrared and, depending on the laser light source used, ultraviolet laser light.

As an alternative to the use of laser arrays disposed on a flexible circuit board such as 20 as seen in FIGURE 1 , it is possible to provide a fiber optic bundle 1 10 which conducts laser beams along the length thereof, and emit the laser beams along the lengths of the fiber optic bundle 1 10.

The fiber optic bundle 110 is comprised of a plurality of fiber optic rods or strands 1 12 formed preferably of polymethylmethacrylate and having a series of abrasions 1 14 selectively disposed along a predetermined length thereof (preferably with .01 to .02 inches between abrasions). The abrasions 114 cause the laser beams which travel in a direction 120 to "leak" through the abrasions 114 into the surrounding material. The laser beams are generated by a plurality of lasers 16 which are disposed in a laser power supply and control device 118 which is substantially identical to that discussed in the above embodiments with the exception that the lasers 116 form a part of the power supply and control device 1 18. The fiber optic strands, which are preferably formed of a flexible, optically clear material, are disposed within a flexible ribbon cable

122 for ease of handling. The lasers 1 16 would preferably be a higher powered laser in order to accommodate the attenuation of the laser beam along the length of the fiber optic strands 1 12. Each of the fiber optic strands is preferably .02 inches in diameter and is formed of a polymethylmethacrylate fiber. The abrasions are formed by hot stamping the PMMA fibers to produce partial breaks in the fibers. This fiber optic ribbon or bundle can be inserted along the length of, for example, the water supply tube 6 illustrated in FIGURE 1 in place of the flexible circuit board 20. In this fashion, the laser light would leak out of the abrasions

1 14 along the entire length of the water tube 6, thereby activating the photochemicals which are compounded into the tube structure 12. As with the other embodiments of the present invention, this embodiment is not limited solely to applications in the dental field, by may be applied to CNS shunts, catheters, and other implantable medical devices.

While the above-discussed features of the present invention represent preferred embodiments of the present invention, it should be understood that the present invention is in no way limited to the features described above. The present invention is best defined by the claims which appear below.

Claims

Clgims

1 . An apparatus for preventing bacterial colonization and adherence in a medical device, comprising: a photochemical disposed on the medical device, the photochemical being activated by light; at least one laser beam generating means for generating a laser beam; and means for irradiating the photochemical with the at least one laser beam, wherein the photochemical releases at least one of singlet oxygen and hydroxyl free radicals in response to being irradiated by the laser beam.

2. An apparatus according to claim 1 , wherein the photochemical comprises a wavelength specific photochemical which activates in response to light having a specified wavelength by releasing at least one of singlet oxygen and hydroxyl free radicals.

3. An apparatus according to claim 2, wherein the medical device comprises a hose for supplying at least one of air and water to a handheld dental tool, the hose being formed of a flexible, resilient material.

4. An apparatus according to claim 3, wherein the material comprises an optically clear material, the photochemical being compounded with the optically clear material.

5. An apparatus according to claim 3, wherein the means for irradiating is disposed in the hose.

6. An apparatus according to claim 5, wherein the hose includes a plurality of bores therein for supplying the at least one of air and water, the means for irradiating being disposed substantially adjacent the plurality of bores.

7. An apparatus according to claim 6, wherein the at least one laser beam generating means is disposed on the means for irradiating.

8. An apparatus according to claim 7, wherein the laser beam generating means comprises a vertical cavity surface emitting laser, and the irradiating means comprises a flexible circuit board disposed inside a predetermined portion of the hose.

9. An apparatus according to claim 7, wherein the flexible, resilient material is optically clear and the photochemical is compounded therewith, the apparatus including a plurality of laser beam generating means, disposed on said means for irradiating, for generating a corresponding plurality of laser beams, the means for irradiating including a flexible circuit board disposed inside a predetermined length of the hose, the plurality of laser beam generating means being disposed on said flexible circuit board and irradiating the photochemical compounded with the flexible, resilient, optically clear material with the corresponding plurality of laser beams.

10. An apparatus according to claim 2, wherein the medical device comprises a catheter for insertion into a patient, the catheter including a hub assembly and a needle.

1 1. An apparatus according to claim 10, wherein the hub assembly is formed of an optically clear material, the photochemical being compounded with the optically clear material.

12. An apparatus according to claim 1 1 , further including a flexible bandage for securing the catheter to the patient, the means for irradiating being disposed in the flexible bandage.

13. An apparatus according to claim 12, wherein the at least one laser beam generating means is disposed on the means for irradiating.

14. An apparatus according to claim 13, wherein the laser beam generating means comprises a vertical cavity surface emitting laser, and the irradiating means comprises a flexible circuit board disposed inside the flexible bandage.

15. An apparatus according to claim 13, further including a plurality of laser beam generating means, disposed on said means for irradiating, for generating a corresponding plurality of laser beams, the means for irradiating including a flexible circuit board disposed within a predetermined portion of said flexible bandage, the plurality of laser beam generating means being disposed on said flexible circuit board such that said plurality of laser beams irradiate from the flexible circuit board to a location exterior of the flexible bandage, wherein the flexible bandage is positioned over the hub assembly and adjacent a location where the needle enters the patient, the plurality of laser beam generating means irradiating the photochemical compounded with the optically clear material with the corresponding plurality of laser beams.

16. An apparatus according to claim 13, further including a portable power supply and controller for controlling a supply of power to the at least one laser beam generating means, means for affixing the portable power supply and controller to the patient, and means for interconnecting the portable power supply and controller to the at least one laser beam generating means.

17. An apparatus according to claim 2, wherein the medical device comprises a vascular graft.

18. An apparatus according to claim 17, wherein the vascular graft is formed of a predetermined material, the photochemical being disposed on the predetermined material.

19. An apparatus according to claim 18, further including a flexible bandage to be applied to a patient in a position substantially adjacent to a location of the vascular graft, the means for irradiating being disposed in the flexible bandage.

20. An apparatus according to claim 19, wherein the at least one laser beam generating means is disposed on the means for irradiating.

21 . An apparatus according to claim 20, wherein the laser beam generating means comprises a vertical cavity surface emitting laser, and the irradiating means comprises a flexible circuit board disposed inside the flexible bandage.

22. An apparatus according to claim 20, further including a plurality of laser beam generating means, disposed on said means for irradiating, for generating a corresponding plurality of laser beams, the means for irradiating including a flexible circuit board disposed within a predetermined portion of said flexible bandage, the plurality of laser beam generating means being disposed on said flexible circuit board such that said plurality of laser beams irradiate from the flexible circuit board to exterior of the flexible bandage, wherein the flexible bandage is positioned over the position substantially adjacent to the location of the vascular graft, the plurality of laser beams irradiating the photochemical disposed on the predetermined material through a skin layer of the patient.

23. An apparatus according to claim 22, further including at least one optical fiber, optically coupled with at least one of the plurality of laser beam generating means, for conveying at least one of said plurality of laser beams to the location of the vascular graft.

24. A method for preventing bacterial colonization and adherence in a medical device, comprising the steps of: disposing a photochemical on the medical device, the photochemical being activated by light; generating at least one laser beam; and irradiating the photochemical with the at least one laser beam, wherein the photochemical releases at least one of singlet oxygen and hydroxyl free radicals in response to being irradiated by the laser beam.

25. A method according to claim 24, wherein the generating step comprises the step of generating a laser beam having a predetermined wavelength, and wherein the photochemical comprises a wavelength specific photochemical which activates in response to light having the predetermined wavelength by releasing at least one of singlet oxygen and hydroxyl free radicals.

26. A method according to claim 25, wherein the step of disposing comprises compounding the photochemical with an optically clear material used to make the medical device.

27. A method according to claim 26, wherein the irradiating step comprises irradiating the photochemical from a location inside of the medical device.

28. A method according to claim 27, wherein the medical device comprises a hose for supplying at least one of air and water to a handheld dental tool, the hose including a plurality of bores therein for supplying the at least one of air and water, the irradiating step including irradiating the photochemical from a position inside the hose substantially adjacent the plurality of bores.

29. A method according to claim 28, wherein the laser beam is generated by a laser light source, and the irradiating step includes providing a flexible circuit board having the laser light source disposed thereon inside of a predetermined portion of the hose and activating the vertical cavity surface emitting laser to emit a laser beam which radiates outward from said flexible circuit board and irradiates the photochemical compounded with the optically clear material.

30. A method according to claim 29, wherein the irradiating step includes providing a flexible circuit board having a plurality of laser light sources disposed thereon to produce a plurality of laser beams, disposing the flexible circuit board inside a predetermined length of the hose, and irradiating the photochemical compounded with the optically clear material with the plurality of laser beams.