Synthesis and characterization of PS-b-PGMA diblock copolymer and its interaction with blood proteins and donepezil

Biocompatible polystyrene-block-poly(glycidyl methacrylate) (PS-b-PGMA) diblock copolymers with different molecular weights were synthesized via atom transfer radical polymerization (ATRP), homopolymers of styrene with narrow molecular weight distribution were prepared and used macroinitiators for block copolymerization. The effect of time, temperature, solvent, and in-feed ratio on the synthesis of the polymer was examined. Human serum albumin (HSA), bovine serum albumin (BSA), globulin (Glb) and hemoglobin (Hb) which are intrinsically fluorescent blood proteins were interacted with the synthesized PS-b-PGMA diblock copolymers. A calibration curve equation was used to calculate the amount of immobilized proteins on the diblock copolymers through fluorescence spectroscopy. These occurred at wavelengths of 280 nm and 324 nm, which correspond to the excitation and emission wavelengths of tyrosine and tryptophan residues. Following the interaction of PS-b-PGMA diblock copolymer with the blood proteins, the protein was subjected to a pharmaceutical active substance, donepezil. The copolymers, homo polymers and protein-polymers along with the drug interactions were characterized using 1H NMR, FT-IR and gel permeation chromatography (GPC), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).