| To address the effects of sample matrix and inefficiency on sensors,a variety of zwitterionic polymers and peptides were biomimetically designed and synthesized in this work,which were easily and efficiently modified on surface plasmon resonance sensor(SPR)sensors for the fabrication of antifouling layers.And two multi-detection methods were developed on the single-channel SPR to improve the detection efficiency.The major research contents are shown as follows.(1)Biomimetic bottlebrush polymers designed for fabrication of antifouling surfaces:Inspired by lubricin,three kinds of bottlebrush zwitterionic polymers were synthesized using atom transfer radical polymerization.By a simple drop casting or online exposure,the polymers can be strongly modified on silica surfaces within 10min and were found to be stable in extremely high-salinity solutions,high pressure condition and under an unprecedented wide range of p H.Meanwhile,the excellent antifouling properties of these polymers against proteins and bacteria were found using SPR,fluorescence and Quartz Crystal Microbalance with Dissipation(QCM-D).And the antifouling mechanism was analyzed using surface forces apparatus.The results showed that very low force existed between lysozyme and the polymer,which proved the excellent antifouling performance of polymers.(2)Synergy between zwitterionic polymer(BB)and hyaluronic acid(HA)for enhancing antifouling performance:Inspired by synovial fluid,BB was mixed with HA,and then modified on the gold sensor surface by online modification to fabricate a synergistic antifouling surface(HA-BB).The HA-BB surface showed a better antifouing performance than the BB-modified and HA-modified surfaces.And the adsorption amount of single protein was very low(0.2 ng/cm~2).For the complex samples like milk and serum,HA-BB surfaces also performed excellent antifouling properties.(3)Biomimetic zwitterionic peptides for fabrication of antifouling surfaces:Two loop and two linear zwitterionic peptides were designed and synthesized.Using online modification,these peptides can be rapidly immobilized on gold sensor surfaces demonstrating excellent antifouling performance against proteins and bacteria.The non-specific protein adsorption on peptide-modified surfaces was as low as 0.6 ng/cm~2,and the bacteria adsorption was reduced by 98.9%.Meanwhile,with the increase in the length of peptide,the antifouling property could be significantly improved.Additionally,compared with traditional chain peptides,the loop peptides showed higher stability and antifouling performance.(4)Design of elution strategy for SPR multiple detection:Based on the immune inhibition format,two conjugates of antigen and bovine serum albumin were grafted on the same channel of the SPR sensor.And different regeneration solutions were screened for sequential analysis.Na OH solution and Gly-HCl solution were successively applied to elute the gentamicin(GEN)antibody and chloramphenicol(CAP)antibody,respectively.According to the response values,the of CAP and GEN can be simultaneously detected by single-channel SPR.The LOD of CAP and GEN were 5.28ng/m L and 2.26 ng/m L,respectively.Furthermore,the spiking milk samples with CAP and GEN validated the assay with recoveries of 77.6–101.1%.(5)Design of sequential sandwich immunoassay for SPR multiple detection:Based on the immune sandwich method,the mouse anti-gentamicin and rabbit anti-melamine antibodies were used as recognition molecules.The secondary antibodies(anti-mouse and anti-rabbit)were successively introduced to interact with the corresponding antibodies,showing sequential responses on a single channel.In a single injection of 50μL,the gentamicin and melamine can be detected simultaniously using single-channel SPR with the LOD of 4.4 ng/m L and 1.3 ng/m L,respectively.The spiking milk and serum samples with CAP and GEN validated the assay with recoveries of 81.6%-118.0%.In addition,with advantages of fast,high efficiency and low sample consumption,the method can be used in more detection systems. |
PDF Full Text Request