Research On The Laser Induced Breakdown Spectroscopy Based Digital Encoding Method Of High-throughput Molecular Biological Detection

As the development of life science and the growing demand of public health,suspension array would be an increasingly essential tool for diagnosis,gene expression and other life science fields.Based on laser induced breakdown spectroscopy(LIBS),we carried a series of researches from the design of novel encoding method to the preparation of encoded microbeads and the design of optical demodulation system,to provide a more stable,accurate and sensitive encoding method for suspension array.Initially,we showed an encoding method of suspension array based on the laser induced breakdown spectroscopy(LIBS).We confirmed that digital multiplexing of LIBS-based encoding method becomes feasible since the microsphere can be coded with direct read-out data of wavelengths.The method can avoid fluorescence signal cross talk between barcodes and analyte tags,which lead to overall advantages in accuracy and stability to current fluorescent multicolor encoding method,promoting the barcodes from analog to digital.The single and dual channel detection experiments demonstrated the availability of this encoding method in actual application.Then,a laser induced breakdown spectroscopy and fluorescence spectroscopy coupled optical system was reported to demodulate digitally encoded suspension array in fluoroimmunoassay.Instead of carrying label signal detection and decoding in fluorescence flow system,the optical demodulation used a slide based laser scanning system to finish the qualitative and quantitative analysis,highly decreasing the difficulty of operation.By separating the decoding procedure of suspension array and adsorption quantity calculation of biomolecules into two independent channels,the cross talk between decoding and label signals in traditional methods had been successfully avoided,which promoted the accuracy of both two processes and realized more sensitive quantitative detection of target biomolecules.Further,we had provided a stable preparation method for laser induced breakdown spectroscopy based digital encoding suspension array.By combining reversed-phase microemulsion and ultraviolet light curing together,we created an one-step system for preparation of microbeads.The stability and universality of this method had been confirmed in preparation of microbeads with different encoding materials.Meanwhile,the prepared hydrophilic surface is more suitable for surface decoration and more resistive to unspecific adsorption in actual detection.With further experiments in surface modification and multiplexed detection,we proved the availability of suspension array in practical application.Finally,we had developed a dual-channel-encoding method for encoded microbeads by the combined fluorescence and LIBS.The spectra measurements demonstrated that the dual-channel-encoding can expand the encoding quantity,highly promoting the encoding potantial.The combined utilization of two kinds of spectrum can expand the diversity of encoding and increase the resistance to interference.One more point,the combined LIBS spectra is independent from fluorescence part,which indicates that the digital signal would not produce any crosstalk with fluorescence encoding signal and label signal,greatly improving the anti-interference ability of recognition process.