Virus inactivation validation studies have been widely applied in the risk assessment of biogenic material-based medical products, such as biological products, animal tissue-derived biomaterials, and allogeneic biomaterials, to decrease the risk of virus transmission. Traditional virus detection methods in an inactivation validation study utilize cell culture as a tool to quantify the infectious virus by observing cytopathic effects (CPEs) after virus inactivation. However, this is susceptible to subjective factors because CPEs must be observed by experts under a microscope during virus titration. In addition, this method is costly and time-and labor-consuming. Molecular biological technologies such as quantitative polymerase chain reaction (qPCR) have been widely used for virus detection but cannot distinguish infectious and noninfectious viruses. Therefore, qPCR cannot be directly applied to virus inactivation validation studies. In this paper, methods to detect viruses and progress in the challenge of differentiating infectious and noninfectious viruses with the combination of pretreatment and qPCR techniques such as the integrated cell culture-qPCR (ICC-qPCR) method are reviewed. In addition, the advantages and disadvantages of each new method, as well as its prospect in virus inactivation validation studies, are discussed.

A novel magnesium phosphate-based gel (TMP-BG) with excellent printability was developed for application in 3D printing.

The aim of this study is to investigate in vitro release and cell response to wear particles of ultrahigh molecular weight polyethylene loaded with alendronate sodium (UHMWPE-ALN), a potent bone resorption inhibitor. Wear particles of UHMWPE-ALN with different ALN contents (0.5 wt % or 1.0 wt %) and size ranges (<45 μm or 45-75 μm) were cocultured with macrophages (RAW264.7) and osteoblasts (MC3T3-E1), respectively. The in vitro ALN release was divided into three stages: an initial burst release, subsequent rapid release, and final slow release. The particle size and ALN content of UHMWPE-ALN wear particles affected the in vitro release mainly during initial burst and rapid release. Compared with the control cells, UHMWPE-ALN wear particles stimulated a significant elevation of tumor necrosis factor-alpha (TNF-α) release from macrophages but had no obvious effect on interleukin-6 release. However, this stimulation of TNF-α release could be reduced by ALN released from UHMWPE-ALN wear particles. The wear particle size had stronger effect of on the macrophages compared with the ALN concentration. After coculture with UHMWPE-ALN wear particles, osteoblast proliferation and alkaline phosphatase activities increased moderately with the increase in particle sizes and ALN concentrations. These results suggest that incorporation of ALN in UHMWPE-ALN may be an effective approach to prevent or reduce particles-induced osteolysis.