The Preparation Of Polymer Brushes Of Poly (Acrylonitrile-g-glycidyl Methacrylate) And The Composites With Aunanoparticles For The Detection Of Tumor Markers

Cancer, as the high fatality rate of disease for human is still a difficulty for scientists to overcome urgently, although medicine development is relatively perfect today. The detection of tumor markers via electrochemical immunosensor could provide the basis for the grade and stage of cancer, cancer screening and risk assessment, then won the time for the early diagnosis and treatment of cancer."Living"/controlled radical polymerization has mild reaction condition, the preparation of polymer molecular weight distribution of narrow advantage, combined with the click chemistry faster, higher efficiency, become the important means of the preparation of polymer brushes. In this paper, the backbone polymer and side chain polymer were prepared via the "living"/controlled radical polymerization method,respectively. Then click chemistry can efficient rapid preparation of controllable polymer brush. The "starlike" composites constructed via the loading reaction of polymer brushes on the surface of gold nanoparticles (AuNPs) was studied for the single and simultaneous high sensitive detection of tumor markers.The polymerization of PGMA with abundant epoxy and terminal carboxyl was investigated via RAFT polymerization with 4-cyano pentanoic acid disulfide generation of benzoic acid (CPADB) as the chain transfer agent (CTA) and AIBN as initiator. The "starlike" composites composed of PGMA modified Gold nanoparticles(AuNPs) via Au-S bonding were applied to the electrochemical immunosensor to achieve the signal amplification for the detection of tumor markers. The detection of tumor markers was carried out with ferrocene as electrochemical tags and carcinoembryonic antigen (CEA) as the target antigen under three electrode system(rGO/AuNPs modified glassy carbon electrodes as working electrode, platinum electrodes as auxiliary electrodes, Ag/AgCl electrode as reference electrode). A relatively low limit of detection (LOD,?2.4 pg/mL) and a comparatively wider detection range (5.85×101-5.85×104 pg/mL) (R2=0.9802) were demonstrated. The new electrochemical immunosensor also exhibited highly selectivity.As the main chain of the polymer brushes, polyacrylonitrile (PAN) with carboxyl and disulfide ester groups was prepared via reversible addition fragmentation chain-transfer radical polymerization (RAFT) with azodiisobutyronitrile (AIBN) as initiator, 4 - cyano pentanoic acid disulfide generation of benzoic acid (CPADB) as chain transfer agent (CTA). As polymer brush side chain, poly (methyl acrylic glycidyl ester) (PGMA) was prepared via atom transfer radical polymerization (ATRP) with ethyl a-bromoisobutyrate (EBIB) as the initiator, CuBr2/PMDETA for catalytic system and L-ascorbic acid as reducing agent. The click chemistry reaction between nitrile and azide group with ammonium chloride as catalyst realized the further modification of PAN. A novel functional polymer brushes of poly(acrylonitrile-g-glycidyl methacrylate)was prepared via the grafting reaction between PAN and PGMA. These experiments can intuitively indicate that the polymerizations of PAN and PGMA obey the first-order kinetics, and the polymer molecular weight distribution of the prepared main chain polymer and side chain polymer were narrow.The terminal dithioester group at the end of polymer backbone chain can be converted to the thiol group via the aminating reaction in the presence of ethylenediamine. The polymer brushes were loaded into the surface of Gold nanoparticles (AuNPs) to prepare Brushes/AuNPs "starlike" composites via Au-S bonding. With formic acid ferrocene (Fc-Ac) and anthraquinone-2-carboxylic acid (Aq)as electrochemical detection signal molecules, prostate antigen (PSA) and AFP (AFP)as the target antigen, the single and simultaneous high sensitive detection of tumor markers were realized under three electrode system (rGO/AuNPs modified glassy carbon electrodes as working electrode, platinum electrodes as auxiliary electrodes,Ag/AgCI electrode as reference electrode). The resulting electrochemical immunoseneor was highly sensitive and selective. In the single detection of a-fetoprotein (AFP) and prostate special antigen (PSA), the detection limit was 0.1 pg/mL for PSA, 0.3 pg/mL for AFP and with the range from 0.1 pg/mL to 1 ng/mL and 1 pg/mL to 1 ng/mL, respectively. When validated, the two tumor markers were simultaneously detected using the resulting electrochemical immunosensor. A limit of detection of 2.2 pg/mL for PSA and 1.8 pg/mL for AFP was demonstrated, respectively.Specifically, the electrochemical immunosensor exhibited good linear relationships with a wider range from 10 pg/mL to 100 ng/mL for PSA and AFP.