Wet Spinning of Silk Fibroin-Based Core-Sheath Fibers.

In order to improve the water absorbency of natural silk and extend its applications in wider areas, silk fibroin (SF)-based fibers were prepared by coaxial wet spinning. Using a custom-made wet spinning device with coaxial spinneret, continuous core-sheath fibers were finally obtained by adjusting the core dope into iota-carrageenan/polyacrylamide hot solution and sheath dope into SF/polyurethane solution. These core-sheath fibers were characterized with respect to morphology, SF secondary structure, mechanical property, and water absorbency.

Fabrication of 3D PDMS Microchannels of Adjustable Cross-Sections via Versatile Gel Templates.

Flexible gel fibers with high stretchability were synthesized from physically cross-linked agar and covalently cross-linked polyacrylamide networks. Such gel material can withstand the temperature required for thermal curing of polydimethylsiloxane (PDMS), when the water in the gel was partially replaced with ethylene glycol. This gel template supported thermal replica molding of PDMS to produce high quality microchannels.

Highly water-absorbing silk yarn with interpenetrating network via in situ polymerization.

Silk was modified via in situ polymerization of two monomers acrylamide and sodium acrylate by swelling in an effective LiBr dissolution system. Swelling of natural silks in LiBr solutions of low concentration was clearly observed under optical microscope, and their conformational changes were revealed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Dissolution tests and FTIR spectra of these modified silks suggested the presence of interpenetrating network of polyacrylamide and poly(sodium acrylate) in the silk yarns.

Graphene oxide-enhanced sol-gel transition sensitivity and drug release performance of an amphiphilic copolymer-based nanocomposite.

We report the fabrication of a highly sensitive amphiphilic copolymer-based nanocomposite incorporating with graphene oxide (GO), which exhibited a low-intensity UV light-triggered sol-gel transition. Non-cytotoxicity was observed for the composite gels after the GO incorporation. Of particular interest were the microchannels that were formed spontaneously within the GO-incorporated UV-gel, which expedited sustained drug release.

Antibacterial modification of an injectable, biodegradable, non-cytotoxic block copolymer-based physical gel with body temperature-stimulated sol-gel transition and controlled drug release.

Biomaterials are being extensively used in various biomedical fields; however, they are readily infected with microorganisms, thus posing a serious threat to the public health care. We herein presented a facile route to the antibacterial modification of an important A-B-A type biomaterial using poly (ethylene glycol) methyl ether (mPEG)- poly(ε-caprolactone) (PCL)-mPEG as a typical model. Inexpensive, commercial bis(2-hydroxyethyl) methylammonium chloride (DMA) was adopted as an antibacterial unit.

Polyethylenimine coated bacterial cellulose nanofiber membrane and application as adsorbent and catalyst.

Bacterial cellulose (BC) nanofiber membranes were simply aminalized by a flush-coating and post-crosslinking method. Firstly, wet BC membranes were flushed through by an aqueous solution of polyethylenimine (PEI) and glycerol diglycidyl ether (GDE) under vacuum suction, then further heated up to 70 °C to crosslink the resultant coating on the surface of the nanofibers. The PEI coated bacterial cellulose (BC@PEI) nanofiber membrane presented excellent adsorption performance for Cu(2+) and Pb(2+) ions from aqueous solutions.

Super-tough and thermo-healable hydrogel - promising for shape-memory absorbent fiber.

Recoverable hydrogels with high stretch and toughness have been synthesized by a one-step radical polymerization. They consist of covalently crosslinked polyacrylamide (PAAm) and ionically crosslinked carrageenan. Such double network (DN) hydrogels can be stretched beyond 20 times their initial length, and their fracture energy reached a high value of ∼9500 J m.

Reversible mechanochromism of a luminescent elastomer.

A novel mechanochromic elastomer was manufactured by doping bis(benzoxazolyl)stibene (BBS) into a thermoplastic polyurethane. Both solution casting and melt compounding approaches were tried with a range of BBS concentrations, and an optimal concentration of 0.5% was selected to investigate the mechanochromic mechanism in detail.