An Autoclavable and Transparent Thermal Cutter for Reliably Sealing Wet Nanofibrous Membranes.

Sealing wet porous membranes is a major challenge when fabricating cell encapsulation devices. Herein, we report the development of an utoclavable ransparent hermal utter (ATTC) for reliably sealing wet nanofibrous membranes. Notably, the ATTC is autoclavable and transparent, thus enabling in situ visualization of the sealing process in a sterile environment and ensuring an appropriate seal.

Bovine Serum Albumin Effect on Collapsing PNIPAM Chains in Aqueous Solutions: Spin Label and Spin Probe Study.

The influence of bovine serum albumin (BSA) on collapsing poly(-isopropylacrylamide) (PNIPAM) chains was studied with turbidimetry and spin probe and spin label electron paramagnetic resonance spectroscopy. An increased ratio of collapsed chains in aqueous solutions in the narrow temperature region near the LCST appeared in the presence of 2.5-10 wt% BSA.

Resveratrol's Impact on the Chondrogenic Reagents' Effects in Cell Sheet Cultures of Wharton's Jelly-Derived MSCs.

Human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) are of great interest in tissue engineering. We obtained hWJ-MSCs from four patients, and then we stimulated their chondrogenic phenotype formation in vitro by adding resveratrol (during cell expansion) and a canonical Wnt pathway activator, LiCl, as well as a Rho-associated protein kinase inhibitor, Y27632 (during differentiation). The effects of the added reagents on the formation of hWJ-MSC sheets destined to repair osteochondral injuries were investigated.

Phase transition and potential biomedical applications of thermoresponsive compositions based on polysaccharides, proteins and DNA: A review.

Smart thermoresponsive polymers have long attracted attention as materials of a great potential for biomedical applications, mainly for drug delivery, tissue engineering and wound dressing, with a special interest to injectable hydrogels. Poly-N-isopropylacrylamide (PNIPAM) is the most important synthetic thermoresponsive polymer due to its physiologically relevant transition temperature. However, the use of unmodified PNIPAM encounters such problems as low biodegradability, low drug loading capacity, slow response to thermal stimuli, and insufficient mechanical robustness.

Visible-Light-Induced Cationic Polymerization of Isobutylene: A Route toward the Synthesis of End-Functional Polyisobutylene.

The visible-light-induced cationic polymerization of isobutylene with a dimanganese decacarbonyl (Mn(CO))/diphenyl iodonium hexafluorophosphate (PhIPF) photoinitiating system in a CHCl/-hexane mixture at -30 °C was reported. It was shown that polymerization is initiated by chloromethylisobutyl carbocations generated by the oxidation of chloromethylisobutyl radicals by PhIPF. The latter are formed via chlorine abstraction from solvent (CHCl) by MnCO· radicals, which are generated by the photoinduced decomposition of Mn(CO), followed by single isobutylene addition.

Macromolecular crowding transforms regenerative medicine by enabling the accelerated development of functional and truly three-dimensional cell assembled micro tissues.

Scaffold-free in vitro organogenesis exploits the innate ability of cells to synthesise and deposit their own extracellular matrix to fabricate tissue-like assemblies. Unfortunately, cell-assembled tissue engineered concepts require prolonged ex vivo culture periods of very high cell numbers for the development of a borderline three-dimensional implantable device, which are associated with phenotypic drift and high manufacturing costs, thus, hindering their clinical translation and commercialisation. Herein, we report the accelerated (10 days) development of a truly three-dimensional (338.

Biomaterials Based on Carbon Nanotube Nanocomposites of Poly(styrene--isobutylene--styrene): The Effect of Nanotube Content on the Mechanical Properties, Biocompatibility and Hemocompatibility.

Nanocomposites based on poly(styrene--isobutylene--styrene) (SIBS) and single-walled carbon nanotubes (CNTs) were prepared and characterized in terms of tensile strength as well as bio- and hemocompatibility. It was shown that modification of CNTs using dodecylamine (DDA), featured by a long non-polar alkane chain, provided much better dispersion of nanotubes in SIBS as compared to unmodified CNTs. As a result of such modification, the tensile strength of the nanocomposite based on SIBS with low molecular weight (M = 40,000 g mol) containing 4% of functionalized CNTs was increased up to 5.

A Hydrophobic Derivative of Ciprofloxacin as a New Photoinitiator of Two-Photon Polymerization: Synthesis and Usage for the Formation of Biocompatible Polylactide-Based 3D Scaffolds.

A hydrophobic derivative of ciprofloxacin, hexanoylated ciprofloxacin (CPF-hex), has been used as a photoinitiator (PI) for two-photon polymerization (2PP) for the first time. We present, here, the synthesis of CPF-hex and its application for 2PP of methacrylate-terminated star-shaped poly (D,L-lactide), as well a systematic study on the optical, physicochemical and mechanical properties of the photocurable resin and prepared three-dimensional scaffolds. CPF-hex exhibited good solubility in the photocurable resin, high absorption at the two-photon wavelength and a low fluorescence quantum yield = 0.

Thin Thermoresponsive Polymer Films for Cell Culture: Elucidating an Unexpected Thermal Phase Behavior by Atomic Force Microscopy.

Application of poly--isopropylacrylamide (PNIPAM) and its more hydrophobic copolymers with --butylacrylamide (NtBA) as supports for cell sheets has been validated in numerous studies. The binary systems of these polymers with water are characterized by a lower critical solution temperature (LCST) in a physiologically favorable region. Upon lowering the temperature below the LCST, PNIPAM chains undergo a globule-to-coil transition, causing the film dissolution and cell sheet detachment.

Design of cross-linked polyisobutylene matrix for efficient encapsulation of quantum dots.

Photoluminescent quantum dots (QDs) are a prominent example of nanomaterials used in practical applications, especially in light-emitting and light-converting devices. Most of the current applications of QDs require formation of thin films or their incorporation in solid matrices. The choice of an appropriate host material capable of preventing QDs from degradation and developing a process of uniform incorporation of QDs in the matrix have become essential scientific and technological challenges.

Biocompatible Nanocomposites Based on Poly(styrene--isobutylene--styrene) and Carbon Nanotubes for Biomedical Application.

In this study, we incorporated carbon nanotubes (CNTs) into poly(styrene--isobutylene--styrene) (SIBS) to investigate the physical characteristics of the resulting nanocomposite and its cytotoxicity to endothelial cells. CNTs were dispersed in chloroform using sonication following the addition of a SIBS solution at different ratios. The resultant nanocomposite films were analyzed by X-ray microtomography, optical and scanning electron microscopy; tensile strength was examined by uniaxial tension testing; hydrophobicity was evaluated using a sessile drop technique; for cytotoxicity analysis, human umbilical vein endothelial cells were cultured on SIBS-CNTs for 3 days.

Novel biodegradable star-shaped polylactide scaffolds for bone regeneration fabricated by two-photon polymerization.

Aim: To assess the properties of 3D biodegradable scaffolds fabricated from novel star-shaped poly(D,L-lactide) (SSL) materials for bone tissue regeneration.

Materials & Methods: The SSL polymer was synthesized using an optimized synthetic procedure and applied for scaffold fabrication by the two-photon polymerization technique. The osteogenic differentiation was controlled using human adipose-derived stem cells cultured for 28 days.

Cationic polymerization of vinyl monomers in aqueous media: from monofunctional oligomers to long-lived polymer chains.

Polymer latexes are easily prepared on a multimillion ton scale in industry using free radical initiated emulsion and suspension polymerizations in water, a cheap, nonviscous, heat-controlling, and environmentally benign solvent. Until recently, researchers had done little investigation into ionic polymerization because even a small amount of water would easily deactivate the conventional catalysts used in these processes. In the last decade, however, cationic polymerization in aqueous media has emerged as a new and attractive method for controlling the polymerization reactions using mild experimental conditions.