SENSORIZED DEVICE FOR THE ANALYSIS OF A FLUID BY MEANS OF ACOUSTIC WAVES

Abstract

A method for the detection of analytes within a fluid, said method comprising the steps of prearranging a sensorized device (100) comprising at least one SAW sensor (110), said or each SAW sensor (110) comprising a substrate (115) having an outer surface (IIS′) comprising at least one piezoelectric portion, at least one emitting interdigital transducer (111) arranged on said piezoelectric portion of said outer surface (115′), said emitting interdigital transducer (111) arranged to emit a surface acoustic wave in response to an input electric signal, at least one reflector electrode (112) arranged on said outer surface (115′), said reflector electrode (112) arranged to reflect said acoustic wave towards said emitting interdigital transducer (111). There are then the steps of adsorbing a plurality of probe molecules on said outer surface (IIS′) of said substrate (115) and/or on said or each emitting interdigital transducer (111) and/or on said or each reflector electrode (112), sending n input electric signals, having respective frequencies fi, with i=1, to said emitting interdigital transducer (111) and subsequent transmission by said or each emitting interdigital transducer (111) of at least one surface acoustic wave, reflecting by said or each reflector electrode (112) of said or each surface acoustic wave emitted, identifying, between said n frequencies/j of said input electric signals, at least one resonance frequency fr corresponding to the generation of a surface acoustic wave having power exceeding a predetermined threshold PT, conveying said fluid on said outer surface (115) and/or on said or each emitting interdigital transducer (111) and/or on said or each reflector electrode (112), removal of said fluid by said outer surface (115) and/or by said or each emitting interdigital transducer (111) and/or by said or each reflector electrode (112), verifying a possible change of value of at least one resonance frequency fr previously identified.

Claims

1. A method for the detection of analytes within a fluid, said method comprising the steps of: prearranging a sensorized device (100) comprising at least one SAW sensor (110), said or each SAW sensor (110) comprising: a substrate (115) having an outer surface (115′) comprising at least one piezoelectric portion; at least one emitting interdigital transducer (111) arranged on said piezoelectric portion of said outer surface (115′), said emitting interdigital transducer (111) arranged to emit a surface acoustic wave in response to an input electric signal; at least one reflector electrode (112) arranged on said outer surface (115′), said reflector electrode (112) arranged to reflect said acoustic wave towards said emitting interdigital transducer (111); adsorbing a plurality of probe molecules on said outer surface (115′) of said substrate (115) and/or on said or each emitting interdigital transducer (111) and/or on said or each reflector electrode (112); sending n input electric signals, having respective frequencies f.sub.i, with i=1, . . . ,n, to said emitting interdigital transducer (111) and subsequent transmission by said or each emitting interdigital transducer (111) of at least one surface acoustic wave; reflecting by said or each reflector electrode (112) said or each emitted surface acoustic wave; identifying, between said n frequencies f.sub.i of said input electric signals, at least one resonance frequency f.sub.r corresponding to the generation of a surface acoustic wave having power exceeding a predetermined threshold P.sub.T; conveying said fluid on said outer surface (115′) and/or on said or each emitting interdigital transducer (111) and/or on said or each reflector electrode (112); removing said fluid by said outer surface (115′) and/or by said or each emitting interdigital transducer (111) and/or by said or each reflector electrode (112); verifying a possible change of value of at least one resonance frequency f.sub.r previously identified; said method characterized in that said sensorized device (100) also comprises an auxiliary interdigital transducer (120), and in that, simultaneously or upstream of said step of conveying said fluid on said outer surface (115′), a step is provided of transmission, by said auxiliary interdigital transducer (120), of a surface acoustic wave having frequency f.sub.t for introducing turbulence in said fluid.

2. The method for the detection of analytes within a fluid, according to claim 1, wherein said step of adsorbing a plurality of probe molecules is carried out on said or each emitting interdigital transducer (111) and/or on said or each reflector electrode (112).

3. The method for the detection of analytes within a fluid, according to claim 1, wherein said frequencies f.sub.i of said n surface acoustic waves emitted by said emitting interdigital transducer (111) are greater than 800 MHz, whereas said frequency f.sub.t emitted by said auxiliary interdigital transducer (120) is less than 800 MHz.

4. The method for the detection of analytes within a fluid, according to claim 1, wherein said sensorized device (100) comprises at least two SAW sensors (110) and a control unit and wherein a step is also provided of comparing the surface acoustic waves reflected by said electrodes reflectors (112) of said at least two SAW sensors (110) for reducing noise and determine with higher precision said or each resonance frequency f.sub.r.

5. The method for the detection of analytes within a fluid, according to claim 1, wherein said sensorized device (100) comprises at least one microfluidic channel (130) arranged to convey said fluid along a predetermined path on said outer surface (115′), in order to contain said fluid in a minimum volume where said analysis is carried out.

6. The method for the detection of analytes within a fluid, according to claim 1, wherein said or each SAW sensor (110) is a R-SAW sensor adapted to generate Rayleigh surface acoustic waves.

7. The method for the detection of analytes within a fluid, according to claim 1, wherein said piezoelectric portion of said substrate (115) is made of Lithium niobate [LN].

8. The method for the detection of analytes within a fluid, according to claim 1, wherein there is a step of defining at least two resonance frequencies f.sub.r.

9. A sensorized device (100) for the detection of analytes within a fluid, said sensorized device (100) comprising at least one SAW sensor (110), said or each SAW sensor (110) comprising: a substrate (115) having an outer surface (115′) comprising at least one piezoelectric portion; an emitting interdigital transducer (111) arranged on said outer surface (115′), said emitting interdigital transducer (111) arranged to emit a surface acoustic wave in response to an input electric signal; at least one reflector electrode (112) arranged on said outer surface (115′), said reflector electrode (112) arranged to reflect said acoustic wave towards said emitting interdigital transducer (111).

10. The sensorized device (100), according to claim 9, wherein an auxiliary interdigital transducer (120) is also provided arranged to emit a surface acoustic wave having frequency f.sub.t for introducing turbulence in said fluid, and wherein said frequencies f.sub.i of said n surface acoustic waves emitted by said emitting interdigital transducer (111) are greater than 800 MHz, whereas said frequency f.sub.t emitted by said auxiliary interdigital transducer (120) is less than 800 MHz.

11. The sensorized device (100), according to claim 9, wherein at least two SAW sensors (110) and a control unit are provided arranged to compare said surface acoustic waves reflected by said electrodes reflectors (112) of said at least two SAW sensors (110) for reducing noise.

12. The sensorized device (100), according to claim 9, wherein at least one microfluidic channel (130) is also provided arranged to convey said fluid along a predetermined path on said outer surface (115′), in order to contain said fluid in a minimum volume where

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Further characteristic and/or advantages of the present invention are more bright with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

[0055] FIG. 1 shows the flow-sheet of a method for the detection of analytes within a fluid, according to the present invention;

[0056] FIG. 2A shows a possible exemplary embodiment of the sensorized device for the detection of analytes within a fluid, according to the present invention;

[0057] FIG. 2B shows another possible exemplary embodiment of the sensorized device;

[0058] FIGS. 3A, 3B, 3C, 3D, 3E and 3F show some possible dispositions of the interdigital transducers and of the reflector electrodes on the outer surface of the substrate.

DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT

[0059] With reference to the flow-sheet 300 of FIG. 1, the method for the detection of analytes within a fluid, according to the present invention, comprises a first step of prearranging a sensorized device 100, of which one possible exemplary embodiment is shown in FIG. 2A [301].

[0060] In particular, the sensorized device 100 of FIG. 2A comprises 4 SAW sensors 110, each of which comprising in turn a substrate 115 having an outer surface 115′ with at least one piezoelectric portion. With reference even at FIGS. 3A, 3B, 3C, 3D, 3E and 3F each SAW sensor 110 comprises at least one emitting interdigital transducer 111 and at least one reflector electrode 112 arranged on the piezoelectric portion of the outer surface 115′. In particular, the emitting interdigital transducer 111 is adapted to emit a surface acoustic wave in response to an input electric signal, whereas the reflector electrode 112 is adapted to reflect the acoustic wave towards the emitting interdigital transducer 111.

[0061] Furthermore, the sensorized device 100 can comprise at least one auxiliary interdigital transducer 120 arranged to emit a surface acoustic wave having frequency f.sub.t for introducing turbulence in the fluid.

[0062] Sill with reference to the flow-sheet 300 of FIG. 1, the method provides then a step of adsorbing a plurality of probe molecules on the outer surface 115′ of the substrate 115 and/or on the electrodes of the emitting interdigital transducer 111 and of the reflector electrode 112 [302].

[0063] Then there is a step of sending n input electric signals, having respective frequencies f.sub.i, with i=1, . . . ,n, to the emitting interdigital transducer 111 and subsequent transmission of at least one surface acoustic wave [303].

[0064] There is then a step of reflecting by said or each reflector electrode 112 of said or each surface acoustic wave emitted [304].

[0065] On the basis of the reflected signal and/or transmitted, it is possible to identify, between the n frequencies f.sub.i of the input electric signals, at least one resonance frequency f.sub.r corresponding to the generation of a surface acoustic wave having power exceeding a predetermined threshold P.sub.T [305]. Such identifying can be carried out graphically, identifying, in the spectrum of the reflected signal, the peaks higher than a certain value, i.e. at which the acoustic wave has been actually generated and therefore at which the energy of the reflected signal is low or zero.

[0066] There is then a step of conveying the fluid at the probe molecules, i.e. on the outer surface 115′ of the substrate 115 and/or on the electrodes of the emitting interdigital transducer 111 and of the reflector electrode 112 [306].

[0067] With reference to FIG. 2B, in a preferred exemplary embodiment, the device 100 comprises at least one microfluidic channel 130 arranged to provide the step of conveying by channelling the fluid along a predetermined path on the outer surface 115′, in order to contain the fluid in a minimum volume where the analysis is carried out. The microfluidic channel 130 may also comprise an analysis chamber 130′ at each SAW sensor 110 for allowing the stationing and/or the movement of the fluid on the electrodes of such SAW sensors 110.

[0068] In a preferred exemplary embodiment, the device 100 comprises at least one auxiliary interdigital transducer 120 arranged to emit a surface acoustic wave having frequency f.sub.t for introducing turbulence in the fluid.

[0069] Then there is a step of removing the fluid by the area wherein it was conveyed [307].

[0070] there is then a step of verifying a possible change of value of at least one resonance frequency f.sub.r previously identified [308].

[0071] The foregoing description some exemplary specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. it is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.