CN1375691A - Multispectral imaging gene chip scanner - Google Patents

Abstract

A multi-spectral imaging gene chip scanner is mainly used for detecting fluorescently labeled gene biochips after hybridization. The laser beam is shaped by a linear shaper and then presented on the chip to be tested as a linear laser beam through a slit reflector. The light signal fed back by the chip to be tested is reflected by the slit reflector and then imaged at the slit light barrier through a photographic optical system. When excited by a multi-wavelength laser beam, it passes through the slit light barrier, the first imaging lens, the dispersion element and the second imaging lens and then is projected onto the detector of the charge coupled device of the planar array or the linear array. Compared with the prior art, the present invention not only simplifies the scanning direction and saves the detection time, but also improves the resolution and accuracy of the detection.

Description

Multispectral Imaging Microarray Scanner

Technical field:

The invention relates to a multispectral imaging gene chip scanner, in particular to a gene chip scanner using laser push-broom multispectral imaging. It is mainly used for detection after hybridization of fluorescently labeled gene biochips. It is generally believed that through the scanning and detection of biochips, including the comparison and analysis of the obtained signals by using corresponding software, people can take advantage of the advantages of high-throughput, simplicity, miniaturization, multi-parameters, intensification, and parallelization of gene chips. It opens up broad application prospects in many fields such as life science, basic medical research, disease diagnosis, new drug development, agriculture, food and environmental protection.

Background technique:

For fluorescently labeled biological gene chips, special gene scanners are required for post-hybridization detection. At present, dedicated gene chip scanners are roughly divided into two categories:

A class is to use laser excitation, based on the gene chip detection system (see prior art [1], Life Sciences & Microarraybiochip System, 1999, http://www.scanarray .com.). The other is to use a high-brightness continuous light source plus a filter for illumination excitation, based on a gene detection system using charge-coupled devices (CCD-charge-coupled devices) as a detection element (see prior art [2], Image Processing Europe May/ June 2001 p20-24, www.imageprocess.com). The background technology of these two different systems is briefly described as follows:

The laser gene chip scanner with PMT as the detection element, as shown in Figure 1, uses a laser beam 1 with a certain wavelength to collimate through the beam expander system synthesized by the lens group (2, 4) when detecting the gene chip, and passes through the two-color Reflected by the mirror 3, it is focused by the objective lens 14 to excite the biological chip 15 marked with fluorescence on the mechanical scanner 13 using a stepping motor. Fluorescence generated after the fluorescent material is excited is collected by the objective lens 14. According to the optical path shown in FIG. 8 to filter the stray light and send it to the photomultiplier tube 9. The photomultiplier tube converts the optical signal into an electrical signal, and the converted electrical signal passes through the signal amplifier 10 , and then converts the analog quantity into a digital quantity through the analog-to-digital conversion 11 and sends it to the computer 12 . The data sent by the computer is processed and analyzed by special data processing software, and various information of the chip under test including images can be obtained. Since it uses a single focused laser beam with a fixed wavelength to scan and excite the sample, it requires either the laser beam or the target chip to move so that the laser scans the entire chip sample. In order to ensure clear imaging and accurate laser focusing, the objective lens 14 needs an automatic focus controller 16 . The laser gene chip scanner using PMT as the detection element takes a long time to detect the gene chip each time, so there are special requirements for the laser. The output of the laser is required to have high beam quality, long-term stability and extremely low noise. It is characterized by high resolution of scanned images.

The gene chip scanner with CCD as the detection element generally has medium resolution. It uses CCD as the detection element; uses high-power xenon lamp as high-brightness continuous excitation light source; changes the excitation wavelength by changing the filter; in order to excite and illuminate the gene chip Uniform, often need to use a beam homogenizer; imaging objective lens is to image the gene chip on the CCD pixel. This gene chip scanner can obtain a larger imaging area at one time. However, at present, the imaging area of the CCD digital camera with the best performance is only 16×12mm (the pixel is 10×10μm). If you want to image the entire chip area of 22×73mm, you need to use an expensive large-size area array CCD. Or splicing several CCD elements, or moving the chip to splice the resulting images. Of course, the image can also be reduced, but at the expense of reducing the resolution and accuracy of the chip scan. Its size and power consumption are relatively large.

In addition, the above-mentioned prior art [1] and [2] these two kinds of gene chip scanners with PMT and CCD as detection elements also have some common shortcomings: for example, the object to be detected or the excitation laser beam must have two directions of XY The detection task can only be completed by the translational movement of the chip scanner, so the chip scanner must have a multi-dimensional motion mechanism; the obtained images need to be spliced after computer data processing, and the accuracy of the motion mechanism and the positioning accuracy of the motion mechanism are very high. The process also becomes more complicated; the scanning of the entire chip takes a long time, so the efficiency is low; the cost of the whole machine is relatively expensive, etc.

Invention content:

In order to overcome the shortcomings of the above two prior technologies, the present invention proposes a biological gene chip scanner as shown in FIG. 2 . The present invention utilizes the photographic optical system 21 to replace the traditional microscope objective lens; uses combined multi-wavelength laser beams (or single-wavelength, single laser beams) to focus and reshape them into linear illumination beams to scan and excite the sample; or linear array) CCD detector 26 plus dispersive element 24 and stepping motor combined push-broom scan mode to achieve improved resolution, measurement range and multi-spectral simultaneous imaging. When testing a chip, it is only necessary to move the tested chip 15 one-dimensionally along the X direction, which can simplify the movement mechanism.

The specific structure of the multispectral imaging gene chip scanner of the present invention comprises: a laser light source 1 is arranged, and the laser beam emitted by the laser light source 1 passes through the beam combiner 17 after passing through the dichroic mirror 5 (the laser beam of a single wavelength does not need to be combined) ) through the spherical lens 18, and through the linear shaper 19 into a linear beam, which passes through the light-transmitting slit of the band slit reflector 20 and presents on the chip under test 15 on the mobile platform 28 as a line beam. The optical signal fed back from the chip under test 15 is reflected by the reflective mirror 20 with a slit, and then imaged on the slit light bar 22 through the photographic optical system 21 . Then pass through the first imaging lens 23 , the dispersion element 24 and the second imaging lens 25 to the detector 26 in sequence. When the laser light source 1 emits a laser beam with a monochromatic wavelength, the detector 26 can be directly placed at the image plane of the photographic optical system 21 . The detector 26 converts the optical signal into an electrical signal, passes through the control data collector 27, and then inputs it into the computer 12 for data processing and analysis.

The detector 26 is a charge-coupled device of an area array or a line array, referred to as a CCD detector for short.

Said photographic optical system 21 is an imaging objective lens, or a camera lens.

Said linear shaper 19 is an optical element that converts the circular laser beam into a linear beam section, and is a prism, or a combination of a prism and an aspheric cylindrical lens.

The dispersion element 24 is a dispersion prism, or a combination of a prism and a transmission grating.

In Fig. 2, the multi-wavelength laser beams emitted by the laser light source 1 are synthesized into one beam through a beam combiner 17 (the beam combiner 17 can be omitted if the laser light source 1 used emits a single laser beam), and then processed by an achromatic The spherical lens 18 passes through the laser beam line shaper 19, and the laser beam converges into a thin line, and passes through the slit reflector 20 with a light-transmitting slit in the middle to illuminate the chip 15 under test. The direction of the thin line of the illuminating laser should be adjusted so that it is consistent with the imaging position and pixel direction of the feedback light signal generated by the fluorescent material on the chip 15 under test excited by the laser. Fluorescence produced by the fluorescent material after being excited by the laser passes through the photographic optical system 25 at the slit stop 22 to form a real image (as using single wavelength, single laser beam excitation, then put the CCD detector 26 at the slit stop 22 and take a picture. the imaging plane of optical system 21), and image on CCD detector 26 through first imaging lens 23, dispersion element 24 and second imaging lens 25, as shown in Figure 2, the spectral imaging direction of photographing optical system 21 and The dispersion direction of slit diaphragm 22 and dispersion element is consistent, and 27 is the synchronization of CCD detector 26, scanning and cooling control data collector, the photoelectric signal that CCD detector receives sends in the computer 12 via 27, and computer 12 will send After data processing and analysis, various information of the detected chip including images can be obtained.

Compared with the prior art, the scanner of the present invention has a linear shaper 19 and a reflector 20 with a slit to shape the excited laser beam into a linear beam. When the chip 15 to be tested is excited, only one-dimensional direction Just push the mobile platform 28, which not only simplifies the scanning direction, but also saves the detection time. The feedback optical signal is imaged by the photographic optical system 21 and the first imaging lens 23 , the dispersion element 24 and the second imaging lens 25 , which improves the detection resolution and accuracy. And can be applied to the measurement of multi-spectrum.

Description of drawings:

Fig. 1 is a structural schematic diagram of a gene chip scanner detection device using a photomultiplier tube (PMT) as a detection element in the prior art [1].

Fig. 2 is a schematic structural diagram of the multi-spectral imaging gene chip scanner of the present invention.

Detailed ways:

The structure of a biological gene chip scanner as shown in FIG. 2 . In the present invention, the photographing optical system 21 is a camera lens, f: 85mm, F2, Jupiter brand, and the effective field of view at the best image plane position is greater than the CCD receiving surface size of the line array. Wherein the laser light source 1 uses a dual-wavelength laser excitation: one is a semiconductor laser with a wavelength of 650nm for the laser light source 102, which can excite Cy5 fluorescent dyes; The 532nm wavelength output by frequency doubling of YAG) laser can excite Cy3 fluorescent dye. These two beams of laser light can be reflected and transmitted by the dichromatic reflector 5 (total reflection of 45 degrees incident on 532nm wavelength, and total transmission of 45 degrees incident on 650nm wavelength). , and then through a linear shaper 19 combined by a prism and an aspheric cylindrical lens, it becomes a linear illuminating beam and passes through a slit reflector 20 with a light-transmitting slit in the middle to illuminate the chip 15 to be tested, and pushes the mobile platform 28 Scan and excite the sample of the chip under test 15; the fluorescence generated by the sample passes through the first imaging lens 23, and the dispersion element 24 and the second imaging lens 25 are imaged on the CCD detector 26 with an equilateral triangular dispersion prism. When detecting the biochip 15, it is sufficient for the stepping motor to move the biochip 15 under test on the moving platform along the X direction. The kinematic mechanism of the prior art is simplified. This push-broom scanning method ensures that the biochip scanner can achieve improved resolution, guaranteed measurement range, and multispectral imaging at the same time. Multiple laser beams with multiple wavelengths are synthesized into one beam by the beam combiner, and then the laser beams are converged into a thin line to illuminate the chip 15 under test after passing through the linear beam shaper 19 . The fluorescent signal generated after the thin line direction and the fluorescent material is excited by the laser passes through the photographic optical system 21 to form a real image at the slit stop 22, and passes through the first imaging lens 23, the dispersion element 24 and the second imaging lens 25 to form a real image on the CCD. Imaging on the detector 26, as shown in FIG. 2, the arrangement direction of the pixels on the CCD detector 26 is consistent with the spectral imaging direction and the dispersion direction of the dispersion element. The data control collector 27 is the synchronization, scanning and cooling control and data acquisition of the CCD detection element. The optical signal received by the CCD detector is transmitted to the computer 12 via 27, and the computer sends the data through data processing and analysis to obtain Various information of the tested biochip 15 including images are displayed.

As a special case, if you only need to use a single wavelength and a single laser beam to excite, then the beam combiner can be omitted, and a linear array CCD detector is placed at the slit diaphragm 22, which is the imaging surface of the photographing optical system 20. The receiving surface of the CCD detector. In this way, the manufacturing cost of the instrument can be greatly reduced, which is beneficial to popularization and application.

Claims (1)

1. multispectral imaging gene chip scanning instrument.Comprise:

＜1〉LASER Light Source (1) is arranged, laser beam is focused on the chip under test (15) that is seated on the mobile platform (28) by passing through spherical lens (18) again behind LASER Light Source (1) the emitted laser bundle process double color reflection mirror (5);

＜2〉light signal that is received by detector (26) converts electric signal to through handling in control data collector (27) the back input computing machine (12);

It is characterized in that:

＜3〉laser beam is passed through linear reshaper (19) after through spherical lens (18) again and is met with narrow that to be presented on behind the catoptron (20) on the chip under test (15) be a Line beam;

＜4〉go up of the reflection of the light signal of feedback by chip under test (15), pass through camera optical system (21) again and be imaged on slit light hurdle (22) and go up to the pixel direction detector (26) consistent with imaging and slit light hurdle (22) direction through band slit catoptron (20);

＜5〉between double color reflection mirror (5) and spherical lens (18), be equipped with bundling device (17), between slit light hurdle (22) and detector (26), be equipped with first imaging len (23) successively, dispersion element (24) and second imaging len (25) along the light beam working direction.

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