Cytocompatible, Photoreversible, and Self-Healing Hydrogels for Regulating Bone Marrow Stromal Cell Differentiation.

Photo-crosslinking and self-healing have received considerable attention for the design of intelligent materials. A novel photostimulated, self-healing, and cytocompatible hydrogel system is reported. A coumarin methacrylate crosslinker is synthesized to modify the polyacrylamide-based hydrogels. With the [2+2] cyclo-addition of coumarin moieties, the hydrogels exhibit excellent self-healing capacity when they are exposed to light with wavelengths at 280 and 365 nm, respectively. To enhance cell compatibility, a poly (amidoamine) crosslinker is also synthesized. Variations in light exposure times and irradiation wavelengths are found to alter the self-healing property of the hydrogels. The hydrogels are shown to induce a regular cellular pattern. The hydrogels are used to regulate bone marrow stromal cells differentiation. The relative mRNA expressions are recorded to monitor the osteogenic differentiation of the cells.

Maternal transfer of dechloranes and their distribution among tissues in contaminated ducks.

The tissue concentrations of dechlorane plus and its analogues were determined in ducks collected from several e-waste recycling villages of Taizhou, China. Compared with the published literature, the relatively high concentrations of these compounds were detected in ducks, indicating serious DP contamination. Since both the duck meat and eggs were important components for diet, this result reminded us of keeping a watchful eye on human dietary exposure to DP and its analogues in this study area. The wet-weight concentrations of DP and its analogues were significantly related to tissue lipid content (p < 0.05), indicating that the lipid pools predominantly impacted the distribution of DPs in ducks. On the basis of lipid adjustment, the significantly lower levels in brain than those in liver and blood, displayed the occurrence of liver sequestration and blood-brain barrier to DP and its analogues in the duck (p < 0.05). The maternal transfer of DP and Mirex was not obviously limited, and the transferring extent of Dec 602 was over one. The stereo-selected accumulation of two DP isomers occurred among tissues with preference to syn-DP in blood, and to anti-DP in brain. The values of lipid-adjusted monodechlorinated products mainly originated from the exterior environment in ducks.

Polychlorinated biphenyls and polybrominated biphenyl ethers in adipose tissue and matched serum from an E-waste recycling area (Wenling, China).

To Date, the knowledge on relationship between PCBs/PBDEs exposure and thyroid hormones (THs) levels during pregnancy still needs to be extended. Meanwhile, studies on congener-specific adipose-serum ratios for PCBs/PBDEs were limited. This study reports the levels of PCBs/PBDEs in serum-adipose tissue samples (n = 64) from expectant women living surrounding e-waste recycling sites in Wenling, China. Their concentrations varied from several to hundreds of ng g(-1) lipid. Maternal exposure to PCBs was associated with lower TSH during pregnancy, suggesting possible implication for maternal health and fetal development. The compound levels between the adipose tissue and matched serum samples were highly correlated (p < 0.001), generating a predicted adipose-serum partitioning relationship for individual PCB congener and PBDE congener. Molecular characteristics, such as Kow value, molecular weight and molecular volume, may play a key role in the variable partitioning of some compounds between serum and adipose tissue.

Adipose stem cell-laden injectable thermosensitive hydrogel reconstructing depressed defects in rats: filler and scaffold.

Facial depressed defects are a common cosmetic problem. Temporary fillers need to be re-injected frequently to maintain the desired outcomes. Here, the feasibility of a novel type of injectable hydrogel for persistent effect is demonstrated. We first useed agmatine to synthesize a poly(amidoamine) (PAA) to form a cell-attachable crosslinker and then the crosslinker was co-polymerized with N-isopropylacrylamide to obtain an injectable and temperature sensitive hydrogel. 1H NMR showed the successful synthesis of the crosslinker. In vitro tests, CCK-8 assay and live/dead viability test showed that the hydrogel was non-toxic to adipose-derived stem cells (ASCs). SEM images also confirmed that ASCs could adhere to the hydrogel. Then we constructed a novel depressed defect model in rats and injected four different fillers in the depressed defects: (1) the hydrogel with ASCs, (2) the hydrogel only, (3) hyaluronic acid, and (4) PBS. After 4 weeks, gross and histological analyses showed the defects in hydrogel, hydrogel + ASCs, and HA groups improved significantly and there were no significant differences among them. Significant differences in thickness from skin to muscle in the defect was found between the hydrogel + ASCs group and the other groups after 6 months. The hydrogels degraded completely in defects in both the hydrogel group and the hydrogel + ASCs group, and were filled with adipocytes and multilocular immature adipocytes. Immunohistochemical study using s-100 and perilipin staining revealed adipocyte differentiation in the defect sites. We also used green fluorescent protein (GFP)-ASCs for tracing and found that exogenous added ASCs were involved in adipogenesis. In conclusion, such a cell attachable thermosensitive hydrogel has definite potential not only as a filler but also as a scaffold, and has a persistent effect for small depressed defects. It might ultimately become a new material in plastic and reconstructive surgery.