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Acellular dermal matrix (ADM) is a biomaterial, which commonly used for repair of tissue defects; however, infection is the main factor underlying the failure of treatments involving ADM. To enhance the anti-infection ability of ADM, we constructed a new form of ADM that was decorated with nano-silver (‘NS-ADM’). The introduction of nano-silver did not destroy the decellularized structure of ADM, and no significant difference was detected with regards to the maximum tensile force when compared between NS-ADM and ADM (P = 0.351). NS-ADM was not cytotoxic to cell growth when the concentration of nano-silver solution ≤ 25 ppm and exhibited strong antibacterial activity in vitro. Besides, when rats were inoculated with 104 CFU/mL, there were significantly lower bacterial counts in the NS-ADM group than in the ADM group when assessed seven days after surgery (P = 0.047); no significant differences were detected on days 14 and 28. Although there were no significant differences in bacterial counts on days 7, 14, or 21 between the two groups (rats were inoculated with 106 CFU/mL), the number of rats showing reduced bacterial counts or clearing was higher in the NS-ADM group than in the ADM group. Rats that were inoculated with 108 CFU/mL showed repair failure. Overall, NS-ADM is a promising antibacterial biomaterial for repairing contaminated soft-tissue defects, in which antibacterial properties are superior to ADM. The antibacterial activity of NS-ADM was limited for severe infections, and further in vivo studies are needed to evaluate its efficacy and biosafety.

Graft rejection, with the possibility of a violent immune response, may be severe and life threatening. Our aim was to thoroughly investigate the biocompatibility and immunotoxicology of collagen-based dermal matrix (DM) before assessment in clinical trials.DM was subcutaneously implanted in BALB/c mice in two doses to induce a potential immune response. The spleen and lymph nodes were assessed for shape, cell number, cell phenotype via flow cytometry, cell activation via CCK8 kit, Annexin V kit, and Ki67 immunostaining. Serum samples were used to measure antibody concentration by enzyme-linked immunosorbent assay. Local inflammation was analyzed by histology and immunohistochemistry staining. Data analysis was performed by one-way ANOVA and non-parametric tests.Our data illustrate that the spleen and lymph node sizes were similar between the negative control mice and mice implanted with DM. However, in the high-dose DM (DM-H) group, the total cell populations in the spleen and lymph nodes, T cells and B cells in the spleen had slight increases in prophase, and the low-dose DM (DM-L) group did not display gross abnormities. Moreover, DM-H initiated moderate cell activation and proliferation in the early phase post-immunization, whereas DM-L did not. Neither DM-H nor DM-L implantation noticeably increased IgM and IgG serum concentrations. Examination of the local cellular response revealed only benign cell infiltration and TNF-α expression in slides of DM in the early phase.Overall, DM-H may have induced a benign temporary acute immune response post-implantation, whereas DM-L had quite low immunogenicity. Thus, this DM can be regarded as a safe product.

A kind of PLGA microspheres was prepared with bovine serum albumin (BSA) as the model drug and poly (lactide-co-glycolide) as the matrix. The polylactic acid/hydroxyapatite (PLA/HA) scaffold was manufactured through 3D printing technology. Then the PLGA microspheres were composited in the scaffold. It was also explored about the feasibility of skeletal scaffolds loaded with bone growth factor. The BSA loading PLGA microspheres were prepared by W/O/W method and the scaffolds were prepared by 3D-printing using PLA and HA as raw materials. The composite scaffold was fabricated by adsorbing the microspheres/ethanol suspension into scaffolds under negative pressure. The cell-adhesion ability, hydrophilicity, scaffold morphology, release properties and biocompatibility of the composite scaffold were characterized, respectively. The results show no burst release of BSA from the PLGA microspheres at beginning stage and sustained longer than 35 days. Drug-loading rate of microspheres was 0.64%. PLA/HA scaffold shows enhanced hydrophilicity as well as excellent cell compatibility and cell adhesion property. SEM images show PLGA microspheres were successfully absorbed in PLA/HA scaffold. MTT experiments of the composite scaffold show non cytotoxic and its cell relative proliferation rate is up to 88.37%. These studies show the feasibility of skeletal scaffolds loaded with bone growth factor. Through low-temperature rapid prototyping technology, the long-effective bioactive bone scaffold can be prepared and have a well application prospect.