Engineered Pullulan-Collagen-Gold Nano Composite Improves Mesenchymal Stem Cells Neural Differentiation and Inflammatory Regulation.

Tissue repair engineering supported by nanoparticles and stem cells has been demonstrated as being an efficient strategy for promoting the healing potential during the regeneration of damaged tissues. In the current study, we prepared various nanomaterials including pure Pul, pure Col, Pul-Col, Pul-Au, Pul-Col-Au, and Col-Au to investigate their physicochemical properties, biocompatibility, biological functions, differentiation capacities, and anti-inflammatory abilities through in vitro and in vivo assessments. The physicochemical properties were characterized by SEM, DLS assay, contact angle measurements, UV-Vis spectra, FTIR spectra, SERS, and XPS analysis. The biocompatibility results demonstrated Pul-Col-Au enhanced cell viability, promoted anti-oxidative ability for MSCs and HSFs, and inhibited monocyte and platelet activation. Pul-Col-Au also induced the lowest cell apoptosis and facilitated the MMP activities. Moreover, we evaluated the efficacy of Pul-Col-Au in the enhancement of neuronal differentiation capacities for MSCs. Our animal models elucidated better biocompatibility, as well as the promotion of endothelialization after implanting Pul-Col-Au for a period of one month. The above evidence indicates the excellent biocompatibility, enhancement of neuronal differentiation, and anti-inflammatory capacities, suggesting that the combination of pullulan, collagen, and Au nanoparticles can be potential nanocomposites for neuronal repair, as well as skin tissue regeneration in any further clinical treatments.

Enhanced Biocompatibility and Differentiation Capacity of Mesenchymal Stem Cells on Poly(dimethylsiloxane) by Topographically Patterned Dopamine.

Controlling the behavior of mesenchymal stem cells (MSCs) through topographic patterns is an effective approach for stem cell studies. We, herein, reported a facile method to create a dopamine (DA) pattern on poly(dimethylsiloxane) (PDMS). The topography of micropatterned DA was produced on PDMS after plasma treatment. The grid-topographic-patterned surface of PDMS-DA (PDMS-DA-P) was measured for adhesion force and Young's modulus by atomic force microscopy. The surface of PDMS-DA-P demonstrated less stiff and more elastic characteristics compared to either nonpatterned PDMS-DA or PDMS. The PDMS-DA-P evidently enhanced the differentiation of MSCs into various tissue cells, including nerve, vessel, bone, and fat. We further designed comprehensive experiments to investigate adhesion, proliferation, and differentiation of MSCs in response to PDMS-DA-P and showed that the DA-patterned surface had good biocompatibility and did not activate macrophages or platelets in vitro and had low foreign body reaction in vivo. Besides, it protected MSCs from apoptosis as well as excessive reactive oxygen species (ROS) generation. Particularly, the patterned surface enhanced the differentiation capacity of MSCs toward neural and endothelial cells. The stromal cell-derived factor-1α/CXantiCR4 pathway may be involved in mediating the self-recruitment and promoting the differentiation of MSCs. These findings support the potential application of PDMS-DA-P in either cell treatment or tissue repair.

Needlestick/sharps injuries among vocational school nursing students in southern Taiwan.

BACKGROUND: Although most needlestick/sharps injuries (NSIs/SIs) research focuses on health care workers (HCWs), students in hospital internships are also at risk. Investigations that examined NSIsS/SIs in student populations generally studied medical rather than nursing students (NSs). In 1999, approximately 17,000 Taiwanese nursing graduates were exposed to the hazard of NSIs/SIs. We examined the frequency and mechanism of NSIs/SIs among vocational school NSs in southern Taiwan. METHODS: Between July and December of 1999, within 1 week after the NSs completed their internship training, one of the researchers, who was a teacher in this vocational school, asked them to fill out questionnaires. RESULTS: Five hundred twenty-seven of 550 (92.6%) questionnaires were considered valid. Two hundred sixty-four of 527 (50.1%) responders sustained one or more NSIs/SIs. Ninety-six of 527 (18.2%) responders suffered contaminated NSIs/SIs. The average number of NSIs/SIs per student was 8.0 times/year (4.9 times/student/year for NSIs and 3.1 times/student/year for SIs). NSIs/SIs rates for NSs in 10-week and 4-week internships were significantly different ( P = .039): 53.3% versus 43.7%, respectively. The NSIs/SIs frequencies were influenced by length of internship: 7.3 times/student/year in 10-week internship and 11.7 times/student/year in 4-week internship. Logistic regression analysis indicated that length of internship rotation was statistically significant with respect to contaminated NSIs/SIs (OR = 1.682; 95% CI: 1.005-2.81; P = .048). CONCLUSIONS: The NSIs/SIs frequencies of NSs were higher than those for HCWs. We found that frequency of NSIs/SIs for vocational school NSs is above average. Whether the young age of these NSs put them at greater risk for NSIs/SIs warrants further inquiry.