[Research advances in anaerobic co-digestion of biogas fermentation substrates].

With global climate change, more and more attention has been paid to the development of bio-energy. Biogas fermentation, as a fairly mature technology of bio-matter energy transformation, has received considerable attention and experienced much development. How to improve the efficiency of biogas fermentation and promote its industrialization is a pressing issue. Anaerobic co-digestion is a simple, low-cost, and high-efficiency method for enhancing the efficiency of biogas fermentation, and received increasing attention from related researchers. This paper summarized the characteristics of various fermentation substrates, reviewed the research advances in the co-digestion of animal manure, sewage sludge, and industrial waste, with the focus on the advantages of co-digestion and the factors affecting the rate and efficiency of co-digestion, and prospected the future research of co-digestion and its application, aimed to provide theoretical guidance for the promotion and application of co-digestion techniques.

Proliferation and multi-differentiation potentials of human mesenchymal stem cells on thermoresponsive PDMS surfaces grafted with PNIPAAm.

The thermo-responsivity of PNIPAAm [poly(N-isopropylcarylamide)]-grafted PDMS [poly(dimethylsiloxane)] surface is a property that could be feasibly used for detaching cells adhered on the surface. We used benzophenone-initiated photopolymerization to graft PNIPAAm on PDMS substrates to construct the PNIPAAm-grafted PDMS surface and this PDMS surface was highly thermo-responsive. hMSCs (human mesenchymal stem cells) were used to analyse the proliferation and multi-differentiation of stem cells on the PNIPAAm-grafted PDMS surface. The results showed that hMSCs could adhere on the PNIPAAm-grafted PDMS surface at 37 degrees C and form cell colonies, and then become fibroblastic. The proliferation potential of hMSCs on the PNIPAAm-grafted PDMS surface was not significantly different from that on a plate surface coated with gelatin. However, as it proved easier to detach cells from the surface, by changing temperature, a higher viability of detached cells could be obtained with the PNIPAAm-grafted PDMS surface, using a temperature shift, compared with a gelatin-coated surface, where cells are detached by treatment with trypsin. hMSCs on the PNIPAAm-grafted PDMS surface were induced into osteoblasts, adipocytes and neurocytes under osteogenic medium, adipogenic medium and neurogenic medium respectively. The PNIPAAm-grafted PDMS surface was favourable for osteogenesis of hMSCs, although the potentials of adipogenesis and neurogenesis of hMSCs on the PNIPAAm-grafted PDMS surface were similar to those on the plate surface coated with gelatin. The above results demonstrate that the PNIPAAm-grafted PDMS surface not only kept the potentials of proliferation and multi-differentiation of hMSCs, but also increased the viability of hMSCs.