To investigate how substrate properties influence stem-cell fate, we cultured single human epidermal stem cells on polydimethylsiloxane (PDMS) and polyacrylamide (PAAm) hydrogel surfaces, 0.1 kPa-2.3 MPa in stiffness, with a covalently attached collagen coating. Cell spreading and differentiation were unaffected by polydimethylsiloxane stiffness. However, cells on polyacrylamide of low elastic modulus (0.5 kPa) could not form stable focal adhesions and differentiated as a result of decreased activation of the extracellular-signal-related kinase (ERK)/mitogen-activated protein kinase (MAPK) signalling pathway. The differentiation of human mesenchymal stem cells was also unaffected by PDMS stiffness but regulated by the elastic modulus of PAAm. Dextran penetration measurements indicated that polyacrylamide substrates of low elastic modulus were more porous than stiff substrates, suggesting that the collagen anchoring points would be further apart. We then changed collagen crosslink concentration and used hydrogel-nanoparticle substrates to vary anchoring distance at constant substrate stiffness. Lower collagen anchoring density resulted in increased differentiation. We conclude that stem cells exert a mechanical force on collagen fibres and gauge the feedback to make cell-fate decisions.

Nanofibers exist widely in human tissue with different patterns. Electrospinning nanotechnology has recently gained a new impetus due to the introduction of the concept of biomimetic nanofibers for tissue regeneration. The advanced electrospinning technique is a promising method to fabricate a controllable continuous nanofiber scaffold similar to the natural extracellular matrix. Thus, the biomedical field has become a significant possible application field of electrospun fibers. Although electrospinning has developed rapidly over the past few years, electrospun nanofibers are still at a premature research stage. Further comprehensive and deep studies on electrospun nanofibers are essential for promoting their biomedical applications. Current electrospun fiber materials include natural polymers, synthetic polymers and inorganic substances. This review briefly describes several typically electrospun nanofiber materials or composites that have great potential for tissue regeneration, and describes their fabrication, advantages, drawbacks and future prospects.

A comparative study of antimicrobial activity is done using three different electrospun nanofibers namely-CA, PAN, and PVC used as control and with various amounts of AgNO(3) being treated with UV-irradiation leading to the enhancement of silver nanoparticles. DMF is used as the common solvent which helps to undergo spontaneous slow reduction at room temperature to form silver nanoparticles followed by UV-irradiation using a 400 W source. The time required for the formation of silver nanoparticles is short and they are more or less well dispersed with few such aggregates. The presence of silver nanoparticles is confirmed using various characterization techniques. The antimicrobial activity is studied using nanofibers with fabricated functionality.

While stem cells can sense and respond to physical properties of their environment, the molecular aspects how physical information is translated into biochemical signals remain unknown. Here we show that human mesenchymal stem cells (hMSCs) harvest and assemble plasma fibronectin into their extracellular matrix (ECM) fibrils within 24 hours. hMSCs pro-actively pull on newly assembled fibronectin ECM fibrils, and the fibers are more stretched on rigid than on soft fibronectin-coated polyacrylamide gels. Culturing hMSCs on single stretched fibronectin fibers upregulates hMSC osteogenesis. Osteogenesis was increased when αvβ3 integrins were blocked on relaxed fibronectin fibers, and decreased when α5β1 integrins were blocked or when epidermal growth factor (EGF) receptor signaling was inhibited on stretched fibronectin fibers. This suggests that hMSCs utilize their own contractile forces to translate environmental cues into differential biochemical signals by stretching fibronectin fibrils. Mechanoregulation of fibronectin fibrils may thus serve as check point to regulate hMSC osteogenesis.

To investigate the surgical outcomes of vesiculoscopy on refractory hematospermia and ejaculatory duct obstruction (EDO), the clinical data (including pelvic magnetic resonance imaging (MRI) examinations and the long-term effects of endoscopic treatment) from 305 patients were analyzed. Four main etiologic groups were found on MRI. We found that 62.0% (189/305) of patients showed abnormal signal intensity in MRI investigations in the seminal vesicle (SV) area. Cystic lesions were observed in 36.7% (112/305) of the patients. The third sign was dilatation or enlargement of unilateral or bilateral SV, which were observed in 32.1% (98/305) of the patients. The fourth sign was stone formation in SV or in an adjacent cyst, which was present in 8.5% (26/305) of the patients. The transurethral endoscopy or seminal vesiculoscopy and the related procedures, including fenestration in prostatic utricle (PU), irrigation, lithotripsy, stone removal, biopsy, electroexcision, fulguration, or transurethral resection/incision of the ejaculatory duct (TURED/TUIED), chosen according to the different situations of individual patients were successfully performed in 296 patients. Fenestrations in PU+ seminal vesiculoscopy were performed in 66.6% (197/296) of cases. Seminal vesiculoscopy via the pathological opening in PU was performed in 10.8% (32/296) of cases. TURED/TUIED + seminal vesiculoscopy was performed in 12.8% (38/296) of cases, and seminal vesiculoscopy by the natural orifices of the ejaculatory duct (ED) was performed in 2.4% (7/296) of cases. Electroexcision and fulguration to the abnormal blood vessels or cavernous hemangioma at posterior urethra were performed in 7.4% (22/296) of cases. Two hundred and seventy-one patients were followed up for 6–72 months. The hematospermia of all the patients disappeared within 2–6 weeks, and 93.0% of the patients showed no further hematospermia during follow-up. No obvious postoperative complications were observed. The transurethral seminal vesiculoscopy technique and related procedures are safe and effective approaches for refractory hematospermia and EDO.