Studies on enzymatic degradation of multifunctional composite consisting of chitosan microspheres and shape memory polyurethane matrix

• Published in: Polymer degradation and stability 2020-12, Vol.182, p.109392, Article 109392
• Main Authors: Bil, Monika, Hipś, Izabela, Mrówka, Piotr, Święszkowski, Wojciech
• Format: Article
• Language: English
• Subjects: Biocomposites; Chemicals; Chitosan; Composite materials; Degradation; Differential scanning calorimetry; Hydrolytic degradation; In vitro methods and tests; Lysozyme; Mechanical properties; Microspheres; Morphology; Polyurethane; Polyurethane resins; Scanning electron microscopy; Shape memory; Thermogravimetric analysis; Weight loss measurement
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2020.109392

•In vitro degradation studies of 3b-PU/CH-M composite consisting of chitosan microspheres (CH-M) embedded in polyester-urethane matrix were performed in PBS/Lysozyme medium.•Three stages of the degradation of 3b-PU/CH-M composite were distinguished over 24 weeks.•Morphology changes of CH-M in the outer layer of the composite film and no signs of degradation of CH-M in deeper layers of the composite was observed.•Adhesion of lysozyme on the composite surface and inhibition of mass loss (%) of the composite was observed after 8 weeks of degradation. Degradation studies of the multifunctional 3b-PU/CH-M composite consisting of 2.5 (wt.%) chitosan microspheres (CH-M) incorporated into crosslinked poly(caprolactone/lactide-co-glycolide) (PCL/PLGA) - urethane matrix (3b-PU) were performed in vitro in phosphate buffered saline (PBS) with lysozyme (Lys). The degradation process of the composite was monitored and analyzed via scanning electron microscopy (SEM), weight loss, pH measurement, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA-FTIR). FTIR analysis of chemical structure and mechanical properties measurement were also performed. Three stages of degradation were distinguished during 6 months studies: first - lasting the first 4 weeks associated with morphology changes of CH-M embedded in the outer layer of the composite film and 3% mass loss, followed by significant mass loss up to 20% and pH decrease to 6.5 attributed to degradation of PLGA units observed between 4 and 8 weeks of degradation. The last stage that was characterized by lysozyme adhesion on the composite surface and mass loss inhibition. SEM observations revealed that CH-M dispersed in the deeper layer of the polymer matrix preserved 6 months of degradation in PBS/Lys solution. In vitro test on MG-63 cells revealed no significant effect of the degradation products on cell viability and proliferation.