Nanoparticle Hydrogel Preparation And Application On Biomolecules Identification

Nanoparticle hydrogels?NPs?are a kind of polymers which are in nano-size and water soluble.In recent years,many researchers focus on NPs preparation and application on the identification of peptides,protein and DNA due to their good biocompatibility and strong affinity for biomolecules.In this study,NPs were prepared by precipitation polymerization with the thermosensitive monomer N-isopropylacrylamide?NIPAm?,electrostatic monomers such as acrylic acid?AAc?and methacrylic acid?AAc-CH₃?,hydrophobic monomer like N-t-butylacrylamide?TBAm?and cyclodextrin.A library of NPs was prepared in aqueous solution with changing the variety and recipe of the monomers in polymerization.The obtained NPs have homogeneous morphology,superior dispersibility and uniform sizes ranging from 40 nm to 380 nm according to different NPs proved by Scanning Electron Microscope?SEM?and Dynamic Light Scattering?DLS?,respectively.The NPs were applied in identification of the target peptides?LEVLFQGP and DITNPINLREG?themselves and their His₆-tagged peptides in their C and N terminal,respectively.It is showed that the electrostatic,hydrophobic and hydrogen-bond interaction were the main forces between NPs and peptides.Moreover,the affinity of NPs for peptides was related to the pI value of the peptides,pH value and ionic strength of the recognition solution.His₆-tag can dramatically improve the affinity between them in this study.The adsorption rate of NPs to His₆-DITNPINLREG and His₆-LEVLFQGP was 25 and 15 times higher than that of DITNPINLREG and LEVLFQGP at 35?and pH 5,respectively.Furthermore,the adsorption and desorption of peptides by NPs was also stidied based on their thermosensitivity and pH-sensitivity,while the LCST was confirmed as 5?and the optimized pH value is 5.The NPs were also used in DNA separation with capillary electrophoresis method.Dynamic coating process,thermosensitive gel-filled scheme and monolithic column method were performed in this study.Among them,the dynamic coating process showed high potential in DNA mixture sample?20 nt,50 nt,80 nt?separation.