The In Vitro Enzymatic Degradation of Cross-Linked Poly(trimethylene carbonate) Networks.

Zhipeng Hou,Liqun Yang,Wei Zhang,Miao Li,Jianxin Li,Jianshe Hu,Zhangpei Chen,Jing Guo

doi:10.3390/polym9110605

Abstract

The in vitro enzymatic degradation of cross-linked poly(trimethylene carbonate) networks (PTMC-Ns) was performed in lipase solutions at 37 °C, and the effect of the initial molecular weight and cross-linker amount as well as the cross-linker type on the degradation rate of PTMC-Ns was investigated. Due to their denser structure and more hydrophobic surface as well as the higher glass transition temperature, a slower degradation rate was seen for PTMC-Ns with high initial molecular weight at a given cross-linker amount. Similar results could be observed as the cross-linker amount increased, and cross-linker type also influenced the degradation rate of PTMC-Ns. Furthermore, the enzymatic degradation of PTMC-Ns was accelerated by the surfactants role of lipase via surface erosion mechanism, the enzymatic degradation rate was higher than that of hydrolysis case. The results indicated that PTMC-Ns were promising candidates for clinical subcutaneous implants, especially due to their tunable degradation rate and enhanced form-stability as well as no acidic degradation products.

Highlights

As one of the most important biodegradable polymers, poly(trimethylene carbonate) (PTMC)has attracted considerable attention in recent years due to its favorable characteristics, such as well-documented biocompatibility, excellent biodegradability and rubber-like properties [1,2,3].On top of that, the degradation products of PTMC are not acidic, which is much better than polyesters to avoid inflammation [4,5,6,7] led by acidic degradation products
To investigate the effect of initial molecular weight and cross-linking amount as well as the cross-linker type on degradation, poly(trimethylene carbonate) networks (PTMC-Ns) were fabricated in different cross-linking conditions, as described in our previous works [25]
Linear PTMC with four different molecular weights in the range of 72–329 kg/mol was cross-linked by 0.1 mol % bis(trimethylene carbonate) (BTB) to prepare PTMC-Ns, and the molecular weight of the linear PTMC was regarded as the initial molecular weight of the PTMC-Ns

Summary

Introduction

As one of the most important biodegradable polymers, poly(trimethylene carbonate) (PTMC)has attracted considerable attention in recent years due to its favorable characteristics, such as well-documented biocompatibility, excellent biodegradability and rubber-like properties [1,2,3].On top of that, the degradation products of PTMC are not acidic, which is much better than polyesters to avoid inflammation [4,5,6,7] led by acidic degradation products. As one of the most important biodegradable polymers, poly(trimethylene carbonate) (PTMC). Further study showed poor compatibility between degradation rate and form-stability of PTMC during in vivo degradation [21]; for example, the degradation rate was slow, the form-stability for low-molecular-weight PTMC was poor; while the form-stability was enhanced, high-molecular-weight PTMC had an undesired faster degradation rate in vivo. It would greatly hinder the extensive application of PTMC in biomedical fields. The exact combination of good form-stability and low degradation rate of PTMC needs to be achieved urgently

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Results

Conclusion