The Influence of Polymer Composition on the Hydrolytic and Enzymatic Degradation of Polyesters and Their Block Copolymers with PDMAEMA.

Maria Kupczak,Anna Mielańczyk,Dorota Neugebauer

doi:10.3390/ma14133636

Maria Kupczak, Anna Mielańczyk + Show 1 more

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https://doi.org/10.3390/ma14133636

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Abstract

Well-defined, semi-degradable polyester/polymethacrylate block copolymers, based on ε-caprolactone (CL), d,l-lactide (DLLA), glycolide (GA) and N,N′-dimethylaminoethyl methacrylate (DMAEMA), were synthesized by ring-opening polymerization (ROP) and atom transfer radical polymerization. Comprehensive degradation studies of poly(ε-caprolactone)-block-poly(N,N′-dimethylaminoethyl methacrylate) (PCL-b-PDMAEMA) on hydrolytic degradation and enzymatic degradation were performed, and those results were compared with the corresponding aliphatic polyester (PCL). The solution pH did not affect the hydrolytic degradation rate of PCL (a 3% Mn loss after six weeks). The presence of a PDMAEMA component in the copolymer chain increased the hydrolysis rates and depended on the solution pH, as PCL-b-PDMAEMA degraded faster in an acidic environment (36% Mn loss determined) than in a slightly alkaline environment (27% Mn loss). Enzymatic degradation of PCL-b-PDMAEMA, poly(d,l-lactide)-block-poly(N,N′-dimethylaminoethyl methacrylate) (PLA-b-PDMAEMA) and poly(lactide-co-glycolide-co-ε-caprolactone)-block-poly(N,N′-dimethylaminoethyl methacrylate) (PLGC-b-PDMAEMA) and the corresponding aliphatic polyesters (PCL, PLA and PLGC) was performed by Novozyme 435. In enzymatic degradation, PLGC degraded almost completely after eleven days. For polyester-b-PDMAEMA copolymers, enzymatic degradation primarily involved the ester bonds in PDMAEMA side chains, and the rate of polyester degradation decreased with the increase in the chain length of PDMAEMA. Amphiphilic copolymers might be used for biomaterials with long-term or midterm applications such as nanoscale drug delivery systems with tunable degradation kinetics.

Highlights

Polymers and polymeric materials are widely used in every area of everyday life, including home appliances, housing, packaging, electronics and construction materials in the automotive and construction industries [1,2]
Linear polymers: PCL, PLA and PLGC were obtained by ring-opening polymerization (ROP)
Amphiphilic block copolymers composed of aliphatic polyesters and PDMAEMA were obtained by combining polymerization techniques such as ATRP and ROP (Scheme S1)

Summary

Introduction

Polymers and polymeric materials are widely used in every area of everyday life, including home appliances, housing, packaging, electronics and construction materials in the automotive and construction industries [1,2]. The increased interest in polymeric materials and their production has accelerated the development of the economy; it has resulted in a significant waste production increase [3,4] These wastes, in turn, pose an environmental threat due to improper waste management, long decomposition times and potentially harmful decomposition products. Biodegradable polymers, due to their unique properties, which are biocompatibility in relation to living tissues, biodegradability and non-immunogenicity, are used, among others, in the biomedical field. They are used as biomaterials for various applications, which include absorbable sutures, bone screws and plates, stents, drug carriers and tissue engineering scaffolds. The advantages of biodegradable polymers as biomedical materials include: no need to remove polymers from the body after fulfilling their role; the long-term toxicity and inflammation caused by low-molecular weight degradation are unlikely to occur since these products can be metabolized or excreted from the body; and sustained release of drugs [8]

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