High-performance Mg-Zn alloy achieved by the ultrafine grain and nanoparticle design.

Improving the comprehensive performance of low alloyed Mg is a significant challenge for biomedical applications. This paper developed a high-performance Mg-Zn alloy with uniform ultrafine grains and nano-precipitates through a straightforward, high-temperature reciprocating equal channel angle extrusion (ECAP) process and researched the microstructure, mechanical property, degradation behaviour, and biocompatibility of the developed alloy. Results showed that the lean Mg-2Zn alloy successfully refined grain to about 1 µm and produced plenty of nano-particles with uniform distribution, providing high comprehensive mechanical properties (YS: 235 MPa, UTS: 267 MPa, EL: 15.6 %). Additionally, Zn-riched nano-particles in the matrix could decrease the Zn aggregation at the corrosion layer-matrix interface and form a dense oxide film, achieving a low degradation rate (0.13 mm/year in vivo). Finally, this work realizes the low alloy content, low cost, and good properties of one biodegradable Mg alloy, which will benefit the promotion of future clinical applications.

Multifunctional Magnesium Anastomosis Staples for Wound Closure and Inhibition of Tumor Recurrence and Metastasis.

Biodegradable magnesium (Mg) implants spontaneously releasing therapeutic agents against tumors are an intriguing therapeutic approach for both tissue repair and tumor treatment. Anastomotic staples are extensively used for wound closure after surgical resection in patients with colorectal tumors. However, the safety of Mg anastomosis implants for intestinal closure and the effect of tumor suppression remain elusive. Here, we used a high-purity Mg staple to study these issues. Based on the results, we found that it has the potential to heal wounds produced after colorectal tumor resection while inhibiting relapse of residual tumor cells in vitro and in vivo. After implantation of Mg staples for 7 weeks in rabbits, the intestinal wound gradually healed with no adverse effects such as leakage or inflammation. Furthermore, the implanted Mg staples inhibit the growth of colorectal tumor cells and block migration to normal organs because of the increased concentration of Mg ions and released hydrogen. Such an antitumor effect is further confirmed by the in vitro cell experiments. Mg significantly induces apoptosis of tumor cells as well as inhibits cell growth and migration. Our work presents a feasible therapeutic opinion to design Mg anastomotic staples to perform wound healing and simultaneously release tumor suppressor elements in vivo to decrease the risk of tumor recurrence and metastasis.