Regulation of protein loading on poly(trimethylene carbonate), poly(l-lactic acid), and their copolymer: Effect of surface enrichment by polymer crystallinity

Poly(trimethylene carbonate) (PTMC), poly(l-lactic acid) (PLA), and their copolymer are of great interest for various biomedical materials. These surface properties have the potential to be used as drug delivery carrier and interface on the biomaterials. PTMC surfaces including functional molecules of cholesterol, lithocholic acid (LA), and poly(ethylene glycol) monomethyl ether (mPEG), were transformed by changing external condition. PTMC including mPEG segment indicated inhibition of protein adsorption due to the surface enrichment of the mPEG. By blending of PTMC including LA unit and mPEG segment, it indicated much more suppression of protein immobilization than that of PTMC including only LA unit. Moreover, by increasing PLA composition in the PTMC–PLA copolymer, surface enrichment of the terminal molecule was inhibited by forming crystal structure by PLA in the membrane. It is considered that the property could be achieved by regulation of protein immobilization and adsorption. As a PTMC derivative, poly(5-methyl-5-carboxyl-1,3-dioxan-2-one) (PMBC) was prepared and total amount of protein immobilization was nicely enhanced. Therefore, more proteins were retained on PMBC surface. This study indicated protein immobilization or adsorption on controlled surface by selecting polymer.

► Surface wettability was regulated by dynamic molecular motion of the polymer.
► Terminal molecular design induced the surface enrichment by surrounding condition.
► The crystallinity of the resulting polymer also induced the surface enrichment.
► The resulting surface is capable of conjugating fluorescence-labeled protein.
► The tunable surface properties were good candidate for biointerface.