Optimization of the nutritional environment for differentiation of human-induced pluripotent stem cells using design of experiments-A proof of concept.

The utilization of human-induced pluripotent stem cells (hiPSCs) in cell therapy has a tremendous potential but faces many practical challenges, including costs associated with cell culture media and growth factors. There is an immediate need to establish an optimized culture platform to direct the differentiation of hiPSCs into germ layers in a defined nutritional microenvironment to generate cost-effective and robust therapeutics. The aim of this study was to identify the optimal nutritional environment by mimicking the in vivo concentrations of three key factors (glucose, pyruvate, and oxygen) during the spontaneous differentiation of hiPSCs derived from cord blood, which greatly differ from the in vitro expansion and differentiation scenarios. Moreover, we hypothesized that the high glucose, pyruvate, and oxygen concentrations found in typical growth media could inhibit the differentiation of certain lineages. A design of experiments was used to investigate the interaction between these three variables during the spontaneous differentiation of hiPSCs. We found that lower oxygen and glucose concentrations enhance the expression of mesodermal (Brachyury, KIF1A) and ectodermal (Nestin, ß-Tubulin) markers. Our findings present a novel approach for efficient directed differentiation of hiPSCs through the manipulation of media components while simultaneously avoiding the usage of growth factors thus reducing costs.

Poly(N-isopropylacrylamide-co-allylamine) (PNIPAM-co-ALA) nanospheres for the thermally triggered release of Bacteriophage K.

Due to the increased prevalence of resistant bacterial isolates which are no longer susceptible to antibiotic treatment, recent emphasis has been placed on finding alternative modes of treatment of wound infections. Bacteriophage have long been investigated for their antimicrobial properties, yet the utilization of phage therapy for the treatment of wound infections relies on a suitable delivery system. Poly(N-isopropylacrylamide) (PNIPAM) is a thermally responsive polymer which undergoes a temperature dependent phase transition at a critical solution temperature. Bacteriophage K has been successfully formulated with PNIPAM nanospheres copolymerized with allylamine (PNIPAM-co-ALA). By utilizing a temperature responsive polymer it has been possible to engineer the nanospheres to collapse at an elevated temperature associated with a bacterial skin infection. The nanogels were reacted with surface deposited maleic anhydride in order to anchor the nanogels to non-woven fabric. Bacteriophage incorporated PNIPAM-co-ALA nanospheres demonstrated successful bacterial lysis of a clinically relevant bacterial isolate - Staphylococcus aureus ST228 at 37°C, whilst bacterial growth was unaffected at 25°C, thus providing a thermally triggered release of bacteriophage.