Enhanced bone regeneration PHA scaffolds coated with polydopamine-captured BMP2.

The hierarchical three-dimensional (3D)-printing scaffolds based on microbial polyester poly(3-hydroxybutyrate--4-hydroxybutyrate) (P34HB) were designed and used for bone tissue engineering surface functionalization on 3D-printed (P34HB) scaffolds using polydopamine (PDA)-mediated recombinant human bone morphogenetic protein-2 (BMP2), leading to enhanced bone formation in a rat model with a calvarial critical-size bone defect. Taking advantage of the adhesive property of PDA under alkaline and aerobic conditions, osteogenic BMP2 was captured on the surface of PHA scaffolds, resulting in their enhanced osteogenic bioactivity, better stem cell adhesion and proliferation, and sustainable release of a bioactive substance over a period of 30 days. These contributed to notable differences in alkaline phosphatase (ALP) activity, mineralization, expressions of osteogenesis-related genes, as well as finally enhanced bone formation in rats.

A Polyhydroxyalkanoates-Based Carrier Platform of Bioactive Substances for Therapeutic Applications.

Bioactive substances (BAS), such as small molecule drugs, proteins, RNA, cells, etc., play a vital role in many therapeutic applications, especially in tissue repair and regeneration. However, the therapeutic effect is still a challenge due to the uncontrollable release and instable physico-chemical properties of bioactive components.

Efficacy and safety of COVID-19 vaccines: a systematic review.

Objective: To evaluate systematically the efficacy and safety of COVID-19 vaccines.

Methods: PubMed, Embase, Cochrane Library, Clinicaltrial.gov, CNKI, Wanfang Data, China Biomedical Literature Service System, and China Clinical Trial Registry were searched for randomized controlled trials of COVID-19 vaccines published up to December 31, 2020.