Multiplex Biodetection Based On Photonic Crystal Beads And SERS Nano-tags

Point-of-care testing?POCT?platform has been a growing part of the healthcare industry due to its rapid provision of results,ease of use,low cost,and in-home health care monitoring.Currently,the most widely used POCT platform is the lateral flow immunoassay?LFIA?LFIA can detect complex analytes due to the specific binding of antigen-antibody interactions.However,despite the numerous advantages of lateral LFIA,there are still some limitations,such as exist the lateral flow time,and easy to cause the hook effect,Thus,many next-generation POCT diagnostics are beginning to explore vertical flow rather than lateral flow.In addition,a single analyte immunoassay is usually not sufficient for clinical diagnosis,while multiplex immunoassay technology has drawn more and more attention due to its high throughput,high sensitivity,faster analysis time and low cost in the field of clinical diagnosis.Therefore,we combined the photonic crystal beads and SERS nanotags applied to the multiplex nucleic acids detection,and developed a vertical flow chip for POCT detection.The study of this paper descriabled as flollows:?1?Fetal sex DNA detection based on inverse opal hydrogel microbeads and SERS nanotag.The results show that this method applied to the detection of fetal sex,the limit of detection?LOD?can reach to fM level,as sensitive as PCR,and no need for expensive instruments and specialized operators.It will have important guiding value for the families with family genetic disease and future works.?2?Multiplex nucleic acids detection based on silica colloidal crystal beads?SCCBs?and SERS nanotags.The SCCBs captured with three different nucleic acid sequences,and the hybridization reactions for multiplex detection were conducted using multiplexed SERS nanotags and target DNA strands to form the"sandwich"complex,and finally by detecting the Raman signal of different tags.The results showed that different nucleic acids have different characteristic peaks,Ebola virus?EV?was 592 cm^-1,and Bacillus anthracis?BA?was 1341 cm^-1 human immunodeficiency virus?HIV?was 1078 cm^-1,1587 cm^-1,2231 cm^-1;Proved that this method can be applied to multiplex detection systems.?3?Developed a Lab-in-a-syringe vertical flow chip and applied to the protein detection based on photonic crystal beads and SERS nanotags.Lab-in-a-syringe detection based on Silica colloidal crystal beads?SCCBs?and SERS nanotag.The SCCBs captured with the antibody are fixed on the NC membrane of the reusable plastic cartridges,and the antigen and the SERS tag are injected into the plastic cartridges,reaction to form a sandwich imunocomplex.Quantitative detection can be performed by measuring the Raman signal of the complex.In order to verify the feasibility of this system,the system was applied to the detection of human IgG,and the results showed that the quantitative range was from 1 pg mL^-1 to 10⁸ pg mL^-1,and the limit of detection?LOD?was 158 fg mL^-1,which is completely suitable for the detection of low concentration biomolecules.In summary,this paper constructs a multi-nucleic acid detection system with high sensitivity,wide range and good stability,and develops a vertical flow chip for protein detection,which realized the detection of nucleic acids and proteins.It is possible to achieve simultaneous detection of nucleic acids and proteins in the future.