Micro and nano plastics release from a single absorbable suture into simulated body fluid.

Synthetic polymers are widely used in medical devices and implants where biocompatibility and mechanical strength are key enablers of emerging technologies. One concern that has not been widely studied is the potential of their microplastics (MPs) release. Here we studied the levels of MP debris released following 8-week in vitro tests on three typical polyglycolic acid (PGA) based absorbable sutures (PGA 100, PGA 90 and PGA 75) and two nonabsorbable sutures (polypropylene-PP and polyamide-PA) in simulated body fluid. The MP release levels ranked from PGA 100 > > PGA 90 > PGA 75 > > PP ∼ PA. A typical PGA 100 suture released 0.63 ± 0.087 million micro (MPs > 1 µm) and 1.96 ± 0.04 million nano (NPs, 200-1000 nm) plastic particles per centimeter. In contrast, no MPs were released from the nonabsorbable sutures under the same conditions. PGA that was co-blended with 10-25% L-lactide or epsilon-caprolactone resulted in a two orders of magnitude lower level of MP release. These results underscore the need to assess the release of nano- and microplastics from medical polymers while applied in the human body and to evaluate possible risks to human health.

Influence of Ga2O3, CuGa2O4 and Cu4O3 phases on the sodium-ion storage behaviour of CuO and its gallium composites.

CuO and its gallium composites with various compositions are successfully fabricated by using a hydrothermal technique followed by calcination at 900 °C. The added Ga precursors formed oxides in the composites, such as Ga2O3, CuGa2O4 and Cu4O3, as confirmed through the X-ray diffraction patterns as well as the HRTEM and SAED patterns. Further HRTEM analysis also confirmed that Cu4O3 and CuGa2O4 phases reside on the surface of CuO in the composites with a CuO : Ga ratio of 90 : 10. The contents of various oxide phases varied when we increased the amount of Ga in the CuO composites. Changing the ratios of CuO and Ga precursors in the composites is quite effective in tailoring the sodium-ion storage behaviour of CuO. The resultant CuO/Ga composites exhibit remarkable electrochemical performance for sodium-ion batteries in terms of capacity, rate capability and cycling performance. The composite containing 90% CuO and 10% Cu/Ga oxides delivers the highest charge capacity of 661 mA h g-1 at a current density of 0.07 A g-1 with a capacity retention of 73.1% even after 500 cycles. The structure and morphology of the composite (90% CuO and 10% Cu/Ga oxides) was successfully retained after 500 cycles, which was confirmed through ex situ XRD, SEM and HRTEM analyses. The composite also exhibited remarkable rate capability in which it delivered 96 mA h g-1 even at a high current density of 6.6 A g-1. The enhanced electrochemical performances of CuO and its gallium composites are attributed to the presence of Cu4O3 and CuGa2O4 phases. The Cu4O3 phase is actively involved in the redox reaction and the CuGa2O4 phase stabilizes the CuO phase and buffers the volume expansion of CuO during cycling. The present approach eplores great opportunities for improving the electrochemical performance of oxide based anode materials for sodium-ion batteries.