Thermoresponsive Poly(N,N-diethylacrylamide-co-glycidyl methacrylate) Copolymers and Its Catalytically Active α-Chymotrypsin Bioconjugate with Enhanced Enzyme Stability

Abstract

Responsive (smart, intelligent, adaptive) polymers have been widely explored for a variety of advanced applications in recent years. The thermoresponsive poly(N,N-diethylacrylamide) (PDEAAm), which has a better biocompatibility than the widely investigated poly(N,N-isopropylacrylamide), has gained increased interest in recent years. In this paper, the successful synthesis, characterization, and bioconjugation of a novel thermoresponsive copolymer, poly(N,N-diethylacrylamide-co-glycidyl methacrylate) (P(DEAAm-co-GMA)), obtained by free radical copolymerization with various comonomer contents and monomer/initiator ratios are reported. It was found that all the investigated copolymers possess LCST-type thermoresponsive behavior with small extent of hysteresis, and the critical solution temperatures (CST), i.e., the cloud and clearing points, decrease linearly with increasing GMA content of these copolymers. The P(DEAAm-co-GMA) copolymer with pendant epoxy groups was found to conjugate efficiently with α-chymotrypsin in a direct, one-step reaction, leading to enzyme–polymer nanoparticle (EPNP) with average size of 56.9 nm. This EPNP also shows reversible thermoresponsive behavior with somewhat higher critical solution temperature than that of the unreacted P(DEAAm-co-GMA). Although the catalytic activity of the enzyme–polymer nanoconjugate is lower than that of the native enzyme, the results of the enzyme activity investigations prove that the pH and thermal stability of the enzyme is significantly enhanced by conjugation the with P(DEAAm-co-GMA) copolymer.

Synthesis and Study of Thermoresponsive Amphiphilic Copolymers via RAFT Polymerization

“…In addition to pNIPAM, some other polymers with LCSTs properties were also recently reported: poly(N,N-dimethylaminoethyl methacrylate) (DMAEMA) [23], poly(2-(Nmorpholine)ethyl methacrylate) (MEMA) [24], poly(N,N-diethylaminoethyl methacrylate) (DEAEMA) [25], poly(N-[2-(diethylamino)ethyl acrylamide) (DEAEAM) [26], poly(N,Ndiethylacrylamide) (DEAAM) [27], and poly(ethylene glycol) methyl ether methacrylate (PEOMEMA) [28]. Among this list, the PEOMEMA compound is the one that has the greatest potential to become superior to NIPAM, which can be considered as the "gold standard" of thermoresponsive polymers so far.…”

Additive manufacturing of smart polymeric composites: Literature review and future perspectives

“…Nidhi et al [173] analyzed the thermosensitive hydrogels using poly(lactide-co-glycolide) block poly(ethylene glycol) block poly(lactide-co-glycolide) (PLGA-PEG-PLGA), showing phase transition close to body temperature with a release of Cy5.5-labeled bovine serum albumin (BSA-Cy5.5). György et al [174] evaluated a new thermoresponsive copolymer, poly(N, N-diethyl acrylamide co-glycidyl methacrylate) (P[DEAAm-co-GMA]) and revealed that not only the polymer composites but enzymes nanoparticles also showed a stimuli response against temperature. Alvi et al [175] answered the issue regarding the drawbacks associated with the local anesthetics by utilizing the chitosan and β-glycerophosphate as a sensitive hydrogel with a phase transition at 37 C. Similarly, other studies are performed on various polymer nanocomposites to examine their thermal properties and stimuli responses like titanium carbide TiC reinforced poly(vinyl chloride)/ poly(ε-caprolactone), [176] anodized titanium surface, [177] ethylene glycol (EG)/propylene glycol (PG)/ methacrylates.…”

Nanomaterials based on thermosensitive polymer in biomedical field

“…(F) (a) Synthesis of glycidyl-functional poly (N,N-diethylacrylamide-co-glycidyl methacrylate) copolymers via free radical copolymerization and the design of enzyme–polymer nanoconjugate with α-chymotrypsin: (b) thermoresponsive behavior of P (DEAAm-co-GMA) copolymers. Reprinted with permission from Kasza et al (2021) . Copyright © 2021 Polymers.…”

“…Compared with widely used PNIPAAm, thermoresponsive poly (N, N-diethyl acrylamide) (PDEAAm) has better biocompatibility. Therefore, the research on PDEAAm and its derivatives has gained increasing attention in recent years ( Kasza et al, 2021 ). Interestingly, its LCST value ranges from 25 to 36°C, approaching the physiological temperature of the human body.…”

“…The results show that the LCST of p (DEAAm-co-GMA) is in the range of 24.8–37.4°C and decreases linearly with the decrease of DEAAm and with the increase of GMA content. In addition, the nanomaterial can also be coupled with protein to further improve its activity and stability ( Figure 3F ) ( Kasza et al, 2021 ). It was reported that the hydrophobic properties of PDEAAm limit its application.…”