Preparation Of Nanoparticles Containing Phenylboric Acid Fragment Structure And Its Application In Protein Detection System

Protein is widely found in body fluids,they are kind of diagnostic biomakers regarding the health state of individuals.The ligand of protein is introduced into the detection system and can be used as the trigger of the response mechanism.In this paper,the nanoparticles system based on phenylboronic acid is combined with organic dye alizarin red S(ARS)to establish the qualitative and quantitative detection of protein by small molecule ligands.We synthesised macro chain transfer agents which ends modified biotin.Then introduced phenylboronic acid group which are capable of complexing with ARS to produce fluorescent chromophore as a hydrophobic fragment monomer to achieve Reversible Addition-Fragmentation Chain Transfer Polymerization(RAFT Polymerization).Three amphiphilic block polymers(Biotin-PEG-block-PAAPBA)with different block ratios were obtained and then nanoparticles were prepared.Protein bind to ligand on the shell of nanoparticle to produce hydrophobic balance changes.The particles become flexible and the phenylboronic acid is partially exposed,they bound to the ARS to produce a fluorescent chromophore in the hydrophobic fragment of the polymer.As a signal derivation method,the detection curve of streptavidin was constructed by the fluorescence emission spectrum and the limit of detection(LOD)was 32.50 ng·mL-1.The yellow nanoparticles with fluorescent signals were self-assembled by using macromolecular complexes formed by the coordination reaction of Biotin-PEG-b/ock-PAAPBA with ARS.When the protein affects the balance of hydrophobicity and hydrophobicity of the particles,the cyclodextrin molecule is introduced as an external stimulus to promote the further disintegration of the particles and react with the boronic acid-ARS complex in the hydrophobic core to release the free ARS which color is purple.The color of solution change from yellow to purple.According to the difference between the fluorescence emission signal of the protein-added nanoparticle solution and the protein-free solution,the protein detection standard curve was obtained.Achieve the qualitative and quantitative characterization of the protein simultaneously.The LOD is 5.85 ng·mL-1,the detection line range is 6.50 ng·mL-1～1.95 μg·mL-1.