Optical device for taking fluorescence and absorbance measurements

Abstract

The present document relates to an optical device configured to measure fluorescence and absorbance in an immunoassay and in wet chemistry, comprising: - an illuminator channel (26) comprising at least one excitation source (28), - a detector channel (34) comprising at least one sensor (36), - a cuvette (130) containing a sample (132) between the illuminator channel (26) and the detector channel (34), - a mixer (38) of optical light between the illuminator channel (26) and the cuvette (130) and a beam splitter (40) between the cuvette (130) and the detector channel (34).

Description

[0001] Optical device for fluorescence and absorbance measurements

[0002] This disclosure relates to the field of absorbance and fluorescence measurements using an optical device.

[0003] This application relates to the field of absorbance and fluorescence measurements.

[0004] In fluorescence measurements, a sample is illuminated with an illumination source at a specific excitation wavelength, for example, 370 nm. The sample then emits another wavelength that is different from the excitation wavelength, for example, 450 nm.

[0005] In absorbance measurements, the attenuation of light due to the presence of a sample is measured. First, a cuvette without a sample is placed. The light source is turned on, and the light received is measured after passing through the empty cuvette or with water. Next, a sample is placed in the cuvette and the light source is turned on. The attenuation of light is measured in the presence of the sample. More precisely, the decimal logarithm of the light measured with an empty cuvette or water divided by the light measured with the sample gives the absorbance of the sample.

[0006] In the prior art, as shown in Figure 1, there is a motorized optical device 2 for absorbance and fluorescence measurements. The motorized optical device 2 is composed of an emission channel 4 with white light 6 and a first lens 8, a first 10 and a second 12 motorized filter wheel, a sample 14 in a cuvette 16 and a detection channel 18. The first motorized filter wheel 10 is moved to select from the white light 6 the wavelength for illuminating the sample 14. At the same time, in the detection channel 18, the second motorized filter wheel 12 is used to select the wavelength for detection purposes. In this case, a broadband illumination source and a broadband detector 20 with a second lens 22 are used. Wavelength selection is performed by means of these first 10 and second 12 motorized filter wheels.

[0007] Therefore, there are two motor parts that exert mechanical stress on the device. In addition, the size of each motorized filter wheel is large. Such a large size of the first 10 and second 12 motorized filter wheels results in a large footprint of the instrument in which these motorized filter wheels must be implemented. Indeed, the arrangement in the prior art is not optimal since the bowl is positioned between the first motorized filter wheel 10 and the second motorized filter wheel 12, two motorized parts are therefore independent and distinct from each other, which multiplies the elements inside the device and makes such a device complex. It also generates reliability problems due to the moving parts of the motorized filter wheels. Moreover, alignment problems arise during the rotation of the motorized filter wheels.This disclosure improves the situation.

[0008] An analysis system is provided comprising an optical device configured to measure fluorescence and absorbance in a biological sample contained in at least one cuvette comprising: an illuminator channel comprising at least one light source for each required light spectrum, a detector channel comprising at least one sensor for measuring said fluorescence and absorbance in said biological sample, an optical light mixer between the illuminator channel and the cuvette and an optical splitter between the cuvette and the detector channel, at least one cuvette configured to contain said biological sample, said cuvette being disposed between the illuminator channel and the detector channel.

[0009] By means of this arrangement, the optical device is configured to evaluate the fluorescence and absorbance measurements in parallel and preferably at the same time and independently but using the same device, which makes it possible to give a complex and precise analysis of the data of said sample.

[0010] The detector channel is configured to filter light as needed without the need for moving parts. The optical device is more stable than prior art optical devices.

[0011] The optical device is configured to be miniaturized and able to be integrated into a measuring instrument.

[0012] By measuring fluorescence and absorbance in parallel and preferably at the same time, the optical device is particularly suitable for immunoassays.

[0013] According to the invention, “in parallel” means in the same analysis cycle with the same device.

[0014] The optical light mixer may be an integrated combination of lenses and glasses configured to transmit a single collimated output beam from the illuminator channel to the cuvette.

[0015] This optical light mixer is composed of small, fixed (non-moving) parts positioned inside a molded housing without special alignments. This optical light mixer allows working with different wavelengths at the same time and using different source drive and detection techniques. The glasses of the optical light mixer may include filters and at least one beam mixer.

[0016] The optical splitter may be an integrated combination of lenses and glasses configured to split the single output beam that has passed through the cuvette into at least two detection beams. This optical splitter is composed of small, fixed (non-moving) parts positioned inside a molded housing without special alignments. This optical splitter allows working with different wavelengths at the same time and using different source drive and detection techniques. The glasses of the optical splitter may include filters and at least one beam splitter.

[0017] The optical light mixer may include a first trichroic prism configured to transmit a single collimated output beam from the illuminator channel to the cuvette.

[0018] The first trichroic prism is configured to avoid wasting energy by selecting specific wavelengths and to obtain a single collimated output beam.

[0019] The illuminator channel may include a first, second, and third light source for a light spectrum.

[0020] The first light source for a light spectrum can be a white LED.

[0021] The second light source for a light spectrum can be a UV LED configured to emit at 340 nm.

[0022] The third light source for a light spectrum can be a UV LED configured to emit at 370 nm.

[0023] The optical splitter may include a second trichroic prism configured to split the single output beam that has passed through the cuvette into first, second, and third detection beams.

[0024] The detector channel may include a first, a second, and a third sensor.

[0025] The first sensor may be a broadband sensor configured to detect wavelengths between 340 and 700 nm.

[0026] The second sensor may be a sensitivity sensor configured to detect a wavelength of 450 nm.

[0027] The second sensor is configured to detect a very weak signal.

[0028] The third sensor can be a sensor configured to detect a wavelength of 450 nm.

[0029] The analysis system includes an analysis consumable including the at least one cuvette configured to contain the biological sample.

[0030] The analytical consumable comprises a disposable body configured to cover and protect a radially shaped strip in which the at least one cuvette is disposed.

[0031] Advantageously, the radially shaped strip comprises a plurality of cups.

[0032] The radially shaped strip is rotatably mounted in the optical device.

[0033] Advantageously, at least one other cuvette is pre-filled with a reagent.

[0034] The analysis system includes an analysis unit configured to analyze signals from the optical device.

[0035] The analysis system comprises at least one warning device, configured at least to communicate the results of the analysis to the user.

[0036] Other features, details and advantages will be presented in the following detailed description and in the figures, in which: Figure 1 represents a schematic view of an optical device of the prior art.

[0037] Figure 2 represents a three-dimensional view of a part of the optical device according to the invention comprising a radially shaped strip open in “part A” and closed in “part B”.

[0038] Figure 3 represents a schematic view of the optical device according to the invention integrated into the radially shaped strip of the present invention.

[0039] Figure 4 shows a schematic view of the illuminator channel and detector channel of the optical device shown in Figure 3.

[0040] Figure 5 shows a schematic view of the optical device of Figure 3 with a detailed view of the illuminator channel and the detector channel, in a reverse side compared to Figure 4.

[0041] Figure 6 represents a schematic view of the optical device illustrated in Figure 4 comprising a light guide, according to the invention.

[0042] Figure 7 represents a schematic view of an optical light mixer and an optical splitter implemented with trichroic prisms, according to the invention.

[0043] Figure 8 shows a three-dimensional view of the optical device.

[0044] Figure 9 shows a schematic view of a mini-spectrometer as a sensor of the optical device.

[0045] Figure 10 shows a three-dimensional view of a cuvette of the present invention with only the output beam collimated.

[0046] Figure 11 is a graph showing a preliminary comparison between the results obtained using the current fluorescence reading device and the results obtained using the optical device of the present invention.

[0047] Figure 12 is a graph representing absorbance tests.

[0048] Figure 13 is a perspective view of one embodiment of the invention.

[0049] The present invention relates to an optical device configured to measure the fluorescence and absorbance of a small volume sample, in the field of immunoassays and / or wet chemistry.

[0050] The invention relates to an analysis system which comprises an analysis consumable 100 provided with at least one cuvette 130 and an optical device which cooperates with said at least one cuvette 130. Referring to Figures 2 to 6, the optical device of the present invention is configured to cooperate with an analysis consumable 100 comprising the at least one cuvette 130 configured to contain the biological sample 132. As can be seen in Figure 2, the analysis consumable 100 comprises a disposable body 110 configured to cover and protect a radially deformed strip 120 in which the at least one cuvette 130 is disposed. Furthermore, the radially shaped strip 120 comprises a plurality of cuvettes 130. The radially shaped strip 130 is rotatably mounted in the optical device of the invention.A four-channel rotating end 140 is disposed on the upper portion of the disposable body 110: three channels may be dedicated to sample pretreatment and one channel may be interfaced with pumping, for example. A dosage marker 150 is disposed on the four-channel rotating end 140 and a band marker 134 is disposed on the radially shaped band 120.

[0051] The optical device further comprises an illuminator channel 26 having at least one light source 28 for each required light spectrum, a cuvette 130 containing a sample 132 to be analyzed, and a detector channel 34. This illuminator channel 26 generates multi-wavelength light from the illuminator channel 26. The detector channel 34 is configured to detect multi-wavelength light. The detector channel 34 comprises at least one sensor 36. The sensor 36 is configured to receive the multi-wavelength light that has passed through the cuvette 130 or emitted by the sample 132 within the cuvette 130. The optical device is configured to evaluate the fluorescence and absorbance measurements in parallel.

[0052] As illustrated in Figures 4, 5 and 6, the illuminator channel 26 and the detector channel 34 are interchangeable. There is no specific position for the illuminator channel 26 and the detector channel 34. This interchangeability provides flexibility in terms of positioning the illuminator 26 and detector channels 34.

[0053] According to Figure 7, an optical light mixer 38 is positioned between the illuminator channel 26 and the cuvette 130. An optical splitter 40 is positioned between the cuvette 130 and the detector channel 34. The at least one light source 28 for the light spectrum is modulated by means of suitable software (FW) and hardware (HW) systems connected to the at least one light source and receivers. These modulator and demodulator blocks are configured to modulate the light and eliminate all noise due to ambient light or also electronic noise.

[0054] The optical light mixer 38 includes at least one first trichroic prism 42. The first trichroic prism 42 is configured to avoid wasting energy by selecting specific wavelengths and to obtain a single collimated output beam 44. Referring to Figures 6 and 7, the first trichroic prism 42 allows at least one light guide 46 to be used.

[0055] Referring to Figures 7 and 8, the illuminator channel 26 may include three light sources for light spectra. The first excitation light source 48 is a white light emitting diode (LED) with a broad excitation source band for a light spectrum. The term "broad band" means wavelengths between, for example, 340 nm and 700 nm. This broad excitation source band for a light spectrum may be used for absorbance testing. The second excitation light source 50 for a light spectrum is, for example, a UV LED configured to emit at 340 nm and the third excitation light source 52 for a light spectrum is, for example, an ultraviolet (UV) LED configured to emit at 370 nm. Each excitation light source for a light spectrum emits a beam at its own wavelength band.This first trichroic prism 42 combines the three different wavelengths into a single output beam 44 which illuminates a face of the cuvette 130 containing the sample 132 to be analyzed. The first trichroic prism 42 is configured to obtain a collimated beam. The optical device further comprises a housing 54 for the cuvette 130 which is positioned between the illuminator channel 26 and the detector channel 34.

[0056] As illustrated in Figure 7, on the side of the detector channel 34, the wavelengths to be detected are selected. The optical splitter 40 may comprise a second trichroic prism 43. This second trichroic prism splits the single output beam 44 into a first 56, a second 58 and a third 60 detection beams. The first 56, the second 58 and the third 60 detection beams are detected using the three sensors. For example, the first sensor 62 may be a broadband sensor detecting wavelengths between 340 nm and 700 nm. As illustrated in Figure 9, the first sensor 62 may be a mini-spectrometer. The selection of the wavelengths to be measured is carried out inside the mini-spectrometer itself. Inside the mini-spectrometer, there is an array of pixels 64 each capable of receiving a specific wavelength 66 (see Figure 9).Each wavelength of the detection beam illuminates a single pixel within the mini-spectrometer. The second sensor 68 may be a sensitivity sensor detecting a wavelength of 450 nm. This second sensor 68 is configured to detect a very weak signal. Since the cuvette 130 contains a small volume of sample 130, very weak signals must be detected by the second sensor 68, particularly for fluorescence measurement. The third sensor 70 may be a sensor detecting a wavelength of 450 nm. The detector channel 34 is configured to filter the light as needed without the need for moving parts. The optical device is more stable than prior art optical devices.

[0057] The optical device uses the same cuvette 130 to perform the fluorescence and / or absorbance measurement. The fluorescence and absorbance measurements can be performed at the same time and / or in parallel. Therefore, there is no crosstalk between the effect of the two tests. The cuvette 130 is configured with a specific material made of different types of plastics. As illustrated in Figure 10, the shape of this cuvette 130 is also particular because the sample volume is very small, usually between 130 pL and 200 pL. The illuminated volume is maximized, and the dead volume is minimized.

[0058] The optical device is configured to be miniaturized and can be integrated into a measuring instrument. This optical device has no moving parts and, therefore, it is stable. The optical device complies with all mechanical constraints.

[0059] By measuring fluorescence and absorbance in parallel, the optical device is particularly suitable for immunoassays and / or wet chemistry. For example, procalcitonin can be measured by fluorescence and creatinine can be measured by absorbance in parallel using the same device during the same cycle. These measurements are useful for the assessment of liver organ failure in sepsis.

[0060] Referring to Figure 8, fluorescence and absorbance measurement tests were performed. The illuminator channel 26 includes three excitation sources for light spectra. The first excitation source 48 for a light spectrum is a broadband white LED excitation source. This broadband excitation source can be used for absorbance tests. The second excitation source 50 for a light spectrum is a UV LED configured to emit at 340 nm and the third excitation source 52 for a light spectrum is a UV LED configured to emit at 370 nm. The optical device further includes a housing 54 for the cuvette that is positioned between the illuminator channel 26 and the detector channel 34. The detector channel 34 includes a micro-spectrometer corresponding to a broadband sensor detecting wavelengths between 340 and 700 nm.An optical light mixer 38 is positioned between the illuminator channel 26 and the cuvette 130. This optical light mixer 38 is a first trichroic prism 42. An optical splitter 40 is positioned between the cuvette 130 and the detector channel 34. A single mini-spectrometer similar to a broadband sensor is positioned between the cuvette 130 and the detector channel 34.

[0061] A preliminary comparison between the results obtained using the current fluorescence reading device and the results obtained using the optical device of the present invention is given as follows. The graph in Figure 11 shows the fluorescence in pure counts on the ordinate 72 and the fluorophore concentrations in "nM" on the abscissa 74. The solid line 76 represents the results obtained using the optical device of the present invention and the broken line 78 represents the results obtained using the current fluorescence measurement instrument. The small difference observed could be due to the different setting of the excitation sources for light spectra and can easily be overlapped using a linear conversion factor.

[0062] Absorbance tests were also carried out. The graph in Figure 12 shows the absorbance 80 on the ordinate 82 and the concentration of the sample in nM on the abscissa 84. The solid line 86 represents the results obtained using the optical device of the present invention and the broken line 88 represents those obtained using a spectrophotometer. The same sample is used. The results obtained using the optical device of the present invention and those obtained using a real absorbance instrument are comparable.

[0063] In the embodiment shown in Figure 13, the illuminator channel 26 includes two sources: a UV (ultraviolet) LED configured to emit at 370 nm and a white LED configured to emit between 400 and 700 nm. The UV LED 82 is configured to measure fluorescence and the white LED 84 is configured to measure absorbance. The two LEDs could be used simultaneously and each modulated at different frequencies. The detector channel 34 includes two sensors: a multi-pixel photon counter (MPPC) sensor 86 configured to measure a low fluorescence signal and a spectrometer 88 configured to measure a high to medium fluorescence signal and absorbance. Both sensors could read simultaneously. The spectrometer could distinguish between fluorescence light or absorbance light by different frequencies used to modulate the two excitation sources (UV LED and white LED).

[0064] The optical light mixer 38 is an integrated combination of lenses and glasses configured to transmit a single collimated output beam 44 from the illuminator channel 26 to the cuvette 130. The optical light mixer 38 includes a first 90 and a second 92 lens, a first mirror 94 configured to refract light emitted by the UV LED, a first beam combiner 96, and a third lens 98. Between the optical light mixer 38 and the cuvette 130, the single collimated output beam 44 passes through a second mirror 204, a lens 206, a filter 208, a tracking lens 210, and a third mirror 212.

[0065] The optical splitter 40 is an integrated combination of lenses and glasses configured to split the single output beam 44 that has passed through the cuvette into at least two detection beams 80. The optical splitter 40 includes at least two lenses 200, two filters, and a beam splitter 202.

Claims

Claims 1. An optical device configured to measure fluorescence and absorbance in an immunoassay and / or wet chemistry sample comprising: an illuminator channel (26) having at least one light source (28) for each required light spectrum, a detector channel (34) having at least one sensor (36) for measuring said fluorescence and absorbance in said immunoassay and / or wet chemistry sample, a cuvette (130) configured to contain said immunoassay or wet chemistry sample (132) between the illuminator channel (26) and the detector channel (34), an optical light mixer (38) between the illuminator channel (26) and the cuvette (130) and an optical splitter (40) between the cuvette (130) and the detector channel (34).

2. The optical device of claim 1, wherein the optical light mixer (38) is an integrated combination of lenses and glasses that is configured to transmit a single collimated output beam (44) from the illuminator channel to the cuvette.

3. Optical device according to one of claims 1 or 2, the optical splitter (40) being an integrated combination of lenses and glasses which is configured to split the single output beam (44) which has passed through the cuvette into at least two detection beams (80).

4. The optical device of claim 1, the optical light mixer (38) comprising a first trichroic prism (42) that is configured to transmit a single collimated output beam (44) from the illuminator channel to the cuvette.

5. An optical device according to claim 4, the illuminator channel (26) comprising a first, a second and a third light source for a light spectrum.

6. Optical device according to claim 1 to 5, the first excitation light source (48) for a light spectrum being a white LED.

7. Optical device according to claim 1 to 6, the second excitation light source (50) for a light spectrum being a UV LED configured to emit at 340 nm.

8. Optical device according to one of claims 1 to 7, the third excitation light source (52) for a light spectrum being a UV LED configured to emit at 370 nm.

9. Optical device according to one of claims 4 to 8, the optical splitter (40) comprising a second trichroic prism (43) configured to split the single output beam (44) which has passed through the cuvette into a first (56), a second (58) and a third (60) detection beam.

10. An optical device according to claim 1 to 9, the detector channel (34) comprising a first (62), a second (68) and a third (70) sensor.

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