WO2015118199A1

WO2015118199A1 - Analytical sensor and method for the production thereof

Info

Publication number: WO2015118199A1
Application number: PCT/ES2015/070059
Authority: WO
Inventors: José Miguel Avellà Oliver; Sergi Beñat MORAIS EZQUERRO; Javier Carrascosa Rubio; Ángel MAQUIEIRA CATALA; Rosa Puchades Pla
Original assignee: Universitat Politècnica De València
Priority date: 2014-02-05
Filing date: 2015-01-29
Publication date: 2015-08-13
Also published as: ES2524744A1; ES2524744B1

Abstract

The invention relates to an analytical sensor and to a method for the production thereof. The sensor is based on the incorporation of a layer of a photosensitive material into a substrate and the deposition of a reactive assay compound on said layer, as well as the optional incorporation of markers in order to obtain high-performance bioassay results. The operating method of the sensor is based on the selective irradiation of the layer of photosensitive material using a source of laser radiation within a given power range, the incidence of the laser causing changes in the photosensitive material and simultaneously in any compounds located on said layer, also optionally incorporating antenna compounds which when activated by the laser beam develop an analytical signal proportional to the concentration thereof.

Description

ANALYTICAL SENSOR AND METHOD OF OBTAINING THE SAME

D E S C R I P C I O N OBJECT OF THE INVENTION

The present invention is framed in the field of sensors.

The object of the invention consists of a device capable of obtaining analytical data by specifically providing a series of laser recordings on a photosensitive surface.

BACKGROUND OF THE INVENTION Instrumentation and automation in Chemistry and Biology have generated a wide range of analytical instrumental techniques that have been consolidated as a reference for their capabilities. These techniques usually present a series of factors that limit their applicability such as their high cost and the requirement of specialized personnel. In addition, the consumption of energy and chemical reagents restricts its portability and environmental sustainability.

For these reasons there is a growing interest in the development of compact, robust, cheap, simple and sustainable sensor systems, applicable in areas such as clinical diagnosis and environmental analysis, among others. A strategy to address this problem includes the use of systems based on mass manufacturing technologies, allowing access to an instrumentation equipped with a high degree of sophistication and compactness at a low price. Along these lines, in recent years chemical sensor system developments have been described in devices such as mobile phones, scanners, touch screens or webcams.

One of the greatest exponents in this field is compact disk technology. Its adaptation to the development of sensor systems has shown great analytical potential, mainly following two approaches. The first is based on the physical modification of polymer surfaces in disk format for transformation into microfluidic devices. These centrifugal analytical systems They allow several unit operations to be carried out quickly and automatically.

The second approach is based on the modification of compact audio / video discs to be used as detection platforms for chemical and biological agents. In this sense, several applications have been developed in microarray format for the determination of organic residues, proteins and nucleic acids. Other applications describe different assay formats, applied to elemental analysis and to interferometric systems. All compact disc systems adapted to the field of analytical data described above are based on data storage technologies CD (Compact Disc), SACD (Super Audio CD), DVD (Digital Versatile Disc) and Bluray disc (BD) , mainly. A new group is the Compact Disc Labeling Technology by irradiation of Thermochromic / photochromic Coatings from now on TERT and which also belong to the group of technologies called "optical disc recording". TERT technology has never been applied to the development of sensor systems. Unlike systems for data storage (CD, DVD, SACD, BD, etc.), TERT is used to create labels on the front of compact discs. For this, the TERT discs contain on this side a photosensitive thermochromic coating that, when irradiated by the TERT recorder, undergoes a color change. An example of a commercial TERT system is called LightScribe, developed by Hewlett-Packard and Lite-On. In commercial equipment, TERT technology is integrated (recorders and discs) with other technologies such as CD and DVD.

DESCRIPTION OF THE INVENTION

The present invention deals with the production of analytical sensors that are obtained through the use of Thermochromic / photochromic Coating Radiation Labeling Technology (which we refer to as TERT throughout this document). TERT systems present a set of additional features for the development of analytical applications to those of the technologies of Compact disc based on data storage (CD, DVD, SACD, BD, etc.). These features open a wide range of possibilities for chemical and physical modification of the surface of this type of discs, which include a support or substrate on which a layer of thermochromic / photochromic material is located, which makes this technology a very useful tool. Powerful and versatile for the design of analytical applications.

The present invention also includes the development of analytical systems, methods and applications based on Compact Disc Labeling Technology by irradiation of Thermochromic / photochromic Coatings. The present invention also contemplates a new analysis methodology that involves the use of thermochromic / photochromic materials as an analysis surface and of markers or plotters capable of interacting with energy sources (heat and / or electromagnetic radiation) and / or with thermochromic materials / Photochromic

The analytical importance of the selective irradiation of the disk resides mainly in two facts: The first is that it allows to irradiate only the surface area of the sensor that contains the test, thus accelerating the reading process and reducing the volume of memory occupied by the records , and the second is that this type of irradiation, in combination with the high power of the laser, poses an interesting option in the development of analytical applications related to the preparation of samples and with the increase in the magnitude of the recorded signal.

On the other hand, the power of the TERT laser source is easily modulated by controlling the recorder.

The laser of the TERT engravers has a doubly pulsed nature, which can generate noise and horizontal bands of zero signal in the records obtained in the time domain. This noise is eliminated using signal processing methods and test formats aimed at increasing sensitivity. Also, the null signal bands are removed by an algorithm that generates a new record, discriminating these rows of data according to their standard deviation.

Since the laser engraving and labeling device with optical discs with photosensitive coatings manages the recognition and rotation of the disc with regardless of the data groove or track, an absence of optical limitations in the irradiation process is achieved. One of the main potentials of compact disc technology is the use of conventional disc readers / recorders as analytical instrumentation. In the disk technology currently adapted (CD, SACD, DVD and BD) to the field of analysis, the movement of the disk is managed following the track or data groove, so that the chemical / physical modification of the surface of the disk must maintain this capacity.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description. where, for illustrative and non-limiting purposes, the following has been represented:

Figure 1.- It shows an explosion of the analytical sensor where its parts are appreciated separately. Figure 2.- Shows a perspective view of the functional analytical sensor.

Figure 3A-3C- Shows a photochromic bioanalysis scheme using the analytical sensor object of the invention where: (A) Thermochromic material after energy transfer to a dispersive marker. (B) Thermochromic material after energy transfer for an antenna type marker. (C) Elements of the essay.

PREFERRED EMBODIMENT OF THE INVENTION This section describes the possible embodiments of an analytical sensor (1) based on a Compact Disc Labeling Technology system by irradiation of Thermochromic / photochromic Photosensitive Coating and its application in the analytical field, from commercial optical recorders and discs that present those labeling capabilities. In this exemplary embodiment, an optical disc recording equipment comprising a device for labeled with a 780 nm laser source and 40 mW of power.

Firstly a coating of a substrate (2) is carried out by means of a layer

(3) of a photosensitive material, be it thermochromic or photochromic. Once said layer (3) is generated, a selective irradiation is carried out to carry out the generation of a motif (4), for this purpose with the said laser labeling device it is irradiated at 780 nm and 40 mW of power on the layer (3). In a preferred embodiment, an optical disk is used that has a surface coated with a thermochromic and / or photosensitive material that is the layer (3) arranged on the opposite side to which the information is stored.

Using a computer, the shape and color (grayscale) of the motif are designed

(4) to be irradiated and a label is obtained by selective irradiation of said layer (3) of the disk, as shown in Figure 1. Use is made of a substrate (2), which may comprise only polycarbonate or also materials other than polycarbonate (PC), with interesting properties such as PMMA, PDMS, polystyrene, metals, metal oxides, silicon, glass, gels, cellulose and derivatives, ceramic materials, etc. Disc recognition and rotation management in the labeling device is carried out by scanning, with an additional sensor integrated in the system and incorporated as standard or by other electronic means of data collection, of information related to movement of the laser such as a coordinate code contained in the disk). In this way the optical properties of the rest of the platform do not interfere in the irradiation process, this fact expands the physical-chemical capabilities of the system for analytical use. This absence of optical limitations in the process of irradiation of the disk allows the introduction of devices and structures in the sensors, a very interesting feature for the integration of compact disk technology in fields such as microfluidics, photonics and interferometry, among others.

The introduction of materials and structures in the discs can be carried out by arrangement on the platforms of creation of conventional discs such as those already known or by coating processes, using techniques such as deposition or "spin coating" among others. Another interesting option is to join the part of the conventional TERT discs that contain the information related to the movement of the laser with circular platforms or other geometries, generating new platforms. Conventional disks compatible with TERT technology are platforms with great potential for the development of sensor systems. Test platforms with a high degree of sophistication are obtained from commercial TERT discs.

High transmittance TERT CD. This platform is obtained by removing all layers other than the substrate on LightScribe CD, keeping the coordinate code printed on the inside of the disk. Two aspects make this album an interesting rehearsal platform.

The first is its high transparency. This improves sensitivity in measures of transmittance of signals that absorb and / or disperse radiation (particulate markers such as carbon, gold, latex, silica, diamond, etc., TMB deposits, silver deposits, etc.) and in measurements by reflectance of signals that reflect radiation. The second interesting aspect is that these platforms allow direct access to the CD track. Access to this microstructure poses a new possibility in the design of sensor systems.

High reflectance DVD TERT. This test platform is prepared by removing the layer of thermochromic / photochromic material from a LightScribe DVD, obtaining a background reflectance equivalent to that obtained in CD / SACD / DVD systems. This fact is interesting in measurements by reflectance of signals that absorb and / or disperse the radiation. The thermochromic coating of commercial labeling optical discs offers attractive analytical possibilities for the development of new sensor systems and biosensors. Two possible embodiments thereof for the application of this material are described below. In a first preferred embodiment a thermochromic coating is used photosensitive for recording information related to the analysis process (situation of the samples, stage of the process, results, etc.). This allows quick and direct access to this information by the user. It is also the object of this invention to use photosensitive coatings, such as coatings formed by thermochromic and / or photochromic materials, as an analysis surface in probe-target molecular recognition assays, using markers or tracers capable of interacting with the energy source ( heat, electromagnetic radiation) and / or with thermochromic / photochromic material.

There are two kinds of markers of this type, dispersives and antenna compounds. The so-called dispersive markers are elements that disperse the energy transferred to the analysis surface, so that the presence of the marker generates a minor color change in the photochromic / thermochromic material), as shown in Figures 3 (A), 3 (C). On the other hand, markers called antenna compounds are elements that increase the transfer of energy to the test surface, so that the positive tests undergo a change in color superior to that of the background, as shown in Figures 3 (B), 3 (C).

This implementation provides, on the one hand, the possibility of presenting to the user the information related to the results of the analysis in a quick, direct, visual and simple way, without the need for specialized training or computer means for the interpretation of the results. This fact confers a high commercial potential, as has been observed in other sensor systems already on the market, such as test strips (pregnancy test); while on the other hand, this format allows a new type of signal development to be carried out. Applications based on probe-target assays usually require a development or amplification stage, to generate the signal or to increase sensitivity, these development stages contemplate chemical processes, such as development with TMB and silver salts, using in these cases as HRP markers and colloidal gold particles, respectively. The test method described here performs the development of the signal physically through the application of energy, instead of through chemical processes which entails a reduction in the cost of the test, increases environmental sustainability and safety for the user and increases simplicity and he degree of analysis automation.

Through probe-target molecular recognition tests, such as the one detailed in Figure 3 (C), we obtain a correlation between the concentration of the target compound (analyte) and the magnitude of the color change, thus recording signals based on photochromism or thermochromism. A multitude of compounds and materials can be used as markers for photochromic bioanalysis in TERT systems. In this case, the markers are elements capable of interacting with the laser source of the TERT recorder and / or with the thermochromic / photochromic material of the discs.

Dispersive markers compatible with the use of TERT systems in photochromic bioanalysis are materials or compounds that limit the intensity of the laser radiation that is transferred to the thermochromic / photochromic material. An example of an applicable dispersive label is the HPM (hollow polymeric microspheres) or polymer microspheres, typically used as opacifying agents in pigment formulations.

On the other hand, antenna markers compatible with the use of TERT systems in photochromic bioanalysis are compounds capable of increasing the energy transferred by the laser source to the thermochromic material. The antenna compounds capture the energy in the form of electromagnetic radiation emitted by the laser source and transfer it to the thermochromic material in the form of heat, thus increasing the color change. Examples of applicable antenna compounds include non-exclusive compounds derived from harmful and porphyrins.

Claims

1. Analytical sensor (1) comprising at least one substrate (2), wherein said analytical sensor (1) is characterized in that it comprises:

"At least one layer (3) of photoreactive material located on the substrate (2),

• at least one motif (4) defined in layer (3) and generated by laser, and

• at least one biosensitive material located in the motif (4) of the layer (3).

2. Analytical sensor (1) according to claim 1 characterized in that the motif (4) is essentially two-dimensional.

3. Analytical sensor (1) according to one of the preceding claims characterized in that the biosensitive material is adapted to act as a capture probe, and is selected from the group consisting of: a protein, nucleic acid, lipid, carbohydrate and materials with properties and behavior similar to those of the natural materials mentioned above.

4. Method of obtaining an analytical sensor (1) characterized in that it comprises:

· Apply a laser radiation on a layer (3) of photoreactive material located on a substrate (2),

• generate, by laser application, at least one motif (4) in the layer (3) by laser action on the photoreactive material of the layer, and

• insert at least one biosensitive material into the motif (4).

5. Method according to claim 4 characterized in that the laser has a wavelength between 640 nm and 790 nm.

Method according to claim 4 or 5, characterized in that the laser to be applied is generated by a red diode with a power between 27mW and 200mW.

7. Method according to any one of claims 4 to 6 characterized in that the laser is applied by means of an optical disc unit.

8. Method according to any one of claims 4 to 7 characterized because the layer (3) and the substrate (2) are comprised in an optical disk with the layer (3) being located on an opposite side to a face intended to hold data and where an inner ring of the disk comprises electronically readable data, data referred to the movement to be performed by the laser.

9. Method according to claim 8 characterized in that the optical disk is "LightScribe" type.

Method according to claim 4 characterized in that the motif (4) has a minimum width corresponding to a horizontal dimension of an incident ray generated by the laser radiation.

1 Method according to claim 4 characterized in that it further comprises inserting at least one marker in the layer (3) of photoreactive material and / or in the biosensitive material.

12. Method according to claim 11 characterized in that the marker is selected from:

• a dispersive marker, which disperses energy from the irradiation received in the layer (3) so that the presence of the marker generates a color change with respect to a background color in the photoreactive material,

• an antenna compound that increases the energy transfer of the irradiation received in the layer (3) so that positive tests experience an increase in color with respect to the background color of the original photoreactive material.