A composite of hydroxyapatite (HA) and polymers prepared from amino acids and glycolic acid (PAG) was synthesized using an in situ melting polycondensation method. The in vitro degradability and bioactivity of the composite were evaluated, as well as its in vitro and in vivo biocompatibility based on subcutaneous and osseous implantation of samples in New Zealand white rabbits for 8 weeks. The results showed that the PAG/HA composite had higher degradability than PAG and showed a typical apatite morphology after immersion in simulated body fluid for 5 d. Both the PAG/HA composite and PAG alone showed excellent in vitro biocompatibility. In the rabbit model, PAG/HA composite could induce formation of new bone tissue after 4 weeks implantation, mainly owing to the excellent in vivo bioactivity of the implant. These results suggest that PAG/HA composites have the potential to guide bone regeneration and could be used as biodegradable biomaterials for bone repair.

A series of reactive oxygen species-responsive degradable poly(amino acid)s (PAAs) was synthesized via in situ melting polycondensation. The PAAs were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and mechanical property analysis. The degradation and biocompatibility of the PAAs were also studied to evaluate their applicability as biomedical materials. The results show that the PAAs possessed semicrystalline amide structures, and the PAA melting temperature decreased gradually with increasing methionine loading. The incorporation of methionine decreased the thermal stability of the matrix, leading to decreases in both the initial and maximum degradation temperatures. The mechanical properties of the PAAs deteriorated as the content of methionine increased. The content of methionine had an obvious effect on PAA degradation, and the PAAs were responsive to the reactive oxygen-rich environment, suggesting that the incorporation of methionine is effective at improving the degradation of PAAs. The PAAs showed great in vitro and in vivo biocompatibilities. Based on the results, these polymers show promise as high-performance materials for biomedical applications.

Bacterial infection caused by medical material is a common problem in the field of medicine. In this work, we aim to develop a novel antimicrobial bioplastic with potential medical value. A novel composite material composed of polyamino acid (PAA) and titanium dioxide/silver nanoparticles (TiO2/Ag NPs) was synthesized by in situ melting polycondensation with different TiO2/Ag loadings. The morphological, antibacterial, mechanical, thermal, and cytotoxicity properties of the PAA/TiO2/Ag composites were investigated. The results showed that uniform nanocomposites with amide bonds were synthesized, and the nanocomposites with 10% TiO2/Ag incorporation exhibited the best thermal and mechanical properties. Cytotoxicity assay showed that the composites significantly promoted the proliferation of MG‐63 cells. The composites showed obvious inhibitory effect on both Escherichia coli and Staphylococcus aureus, and this effect was increased as the TiO2/Ag NPs doping was increased. These PAA/TiO2/Ag composites are suitable for antibacterial and high‐performance biomaterials in the medical field.