异丙基丙烯酰胺水凝胶纳米微球粒径的控制及其对多肽吸附的影响

A library of poly(N-isopropylacrylamide-co-N-tert-butylacrylamide-co-acrylic acid) (P-NIPAm-tBAm-AAc) hydrogel nanoparticles with good dispersion and uniform size were prepared by precipitation polymerization method. Their hydrodynamic diameters were controlled from 71 nm to 304 nm proved by dynamic light scattering (DLS) with adjusting the polymerization formulation, while the PDI values are all below 0.1. Due to the charge repulsion, the particle size increased from 71 nm to 219 nm when the feeding of electrophilic monomer AAc increased from 5% to 50%(mol) in polymerization. Meanwhile, the inverse effect was also revealed on the hydrophobic monomer tBAm, that is, the nanoparticle size decreased along with increasing its feeding ratio. Besides, the increased usage of the surfactant SDS resulted in the microspheres being smaller to 71 nm. It is proved that the NPs size greatly affected their affinity to the target peptides (LEVLFQGP), and the results showed that the adsorption rate increased with decreasing the nanoparticle size. When the molar ratio of AAc was 20% and the diameter was 128 nm, the adsorption rate could reach 90%. Furthermore, the adsorption and desorption experiment was performed with changing the environmental temperature from 35℃ to 5℃ since the volume phase transition temperature (LCST) of NPs is (20±2)℃ proved by DLS. After five times adsorption/desorption circulation experiments, the reduction of NPs adsorption rate on target peptide was below 7%. Therefore, the prepared and screened NPs are size controlled and reusable.