Reinforced Poly(Propylene Carbonate) Composite with Enhanced and Tunable Characteristics, an Alternative for Poly(lactic Acid)

Abstract

The acidic nature of the degradation products of polyesters often leads to unpredictable clinical complications, such as necrosis of host tissues and massive immune cell invasions. In this study, poly(propylene carbonate) (PPC) and starch composite is introduced with superior characteristics as an alternative to polyester-based polymers. The degradation products of PPC-starch composites are mainly carbon dioxide and water; hence, the associated risks to the acidic degradation of polyesters are minimized. Moreover, the compression strength of PPC-starch composites can be tuned over the range of 0.2±0.03 MPa to 33.9±1.51 MPa by changing the starch contents of composites to address different clinical needs. More importantly, the addition of 50 wt % starch enhances the thermal processing capacity of the composites by elevating their decomposition temperature from 245 to 276 °C. Therefore, thermal processing methods, such as extrusion and hot melt compression methods can be used to generate different shapes and structures from PPC-starch composites. We also demonstrated the cytocompatibility and biocompatibility of these composites by conducting in vitro and in vivo tests. For instance, the numbers of osteoblast cells were increased 2.5 fold after 7 days post culture. In addition, PPC composites in subcutaneous mice model resulted in mild inflammatory responses (e.g., the formation of fibrotic tissue) that were diminished from two to 4 weeks postimplantation. The long-term in vivo biodegradation of PPC composites are compared with poly(lactic acid) (PLA). The histochemical analysis revealed that after 8 weeks, the biodegradation of PLA leads to massive immune cell infusion and inflammation at the site, whereas the PPC composites are well-tolerated in vivo. All these results underline the favorable properties of PPC-starch composites as a benign biodegradable biomaterial for fabrication of biomedical implants.

Nanocomposites of Polymeric Biomaterials Containing Carbonate Groups: An Overview

“…Moreover, the average particle size of ST in PPC/ST (50 wt%) and PPC/ST (40 wt%) samples were 27.81 and 26.72 µm, respectively. This size was similar to that of ST particles size prior to mixing with PPC . Figure ccc–ggg represents the field emission scanning electron microscopy (FESEM) photoimages of TPU cells cultured and fixed after 7 d, these reveals that cell spreading and cellular processes were improved in the nHA‐filled TPU NC surface .…”

Carbon Dioxide–Derived Poly(propylene carbonate) as a Matrix for Composites and Nanocomposites: Performances and Applications

“…Due to the water absorption of PPC/starch, the PPC/starch/bioglass samples showed significant swelling over the 12 weeks of study time. In contrast, the PLA samples showed minimal changes over the 12 week period and new bone was found to form after the 12 weeks adjacent to the implants …”

“…Enzymatic degradability is a crucial factor to utilize a polymeric material for biomedical applications. PPC is biodegradable besides its biocompatibility, noncytotoxicity, and noninflammatory properties with a biological system . Therefore, PPC composites with starch, chitosan, gelation, graphene oxide, and hydroxyapatite could find applications in the biomedical fields.…”

“…Therefore, PPC composites with starch, chitosan, gelation, graphene oxide, and hydroxyapatite could find applications in the biomedical fields. Biocompatible and biodegradable PPC composites are appropriate materials for native tissue regeneration because they can mimic the natural morphology of the extracellular matrix (ECM) that surrounds cells . The ECM is mainly composed of a combination of inorganic components and macromolecules (polysaccharides and proteins) with nanoscale diameter fibers .…”

“…The PPC/starch/bioglass samples showed evidence of swelling. Adapted with permission . Copyright 2015, ACS.…”