RESUMEN
Effective masking policies to prevent the spread of airborne infections depend on public access to masks with high filtration efficacy. However, poor face-fit is almost universally present in pleated multilayer disposable face masks, severely limiting both individual and community respiratory protection. We developed a set of simple mask modifications to mass-manufactured disposable masks, the most common type of mask used by the public, that dramatically improves both their personalized fit and performance in a low-cost and scalable manner. These modifications comprise a user-moldable full mask periphery wire, integrated earloop tension adjusters, and an inner flange to trap respiratory droplets. We demonstrate that these simple design changes improves quantitative fit factor by 320%, triples the level of protection against aerosolized droplets, and approaches the model efficacy of N95 respirators in preventing the community spread of COVID-19, for an estimated additional cost of less than 5 cents per mask with automated production. TeaserA personalizable, low-cost mask improves facial fit, reduces user exposure, and decreases spread of contagious aerosols.
RESUMEN
Human pluripotent stem cells (hPSCs) are capable of differentiating into any type of somatic cell, a characteristic that imparts significant therapeutic potential. Human embryonic stem cells and induced pluripotent stem cells are types of hPSCs. Although hPSCs have high therapeutic potential, their clinical relevance is limited by the requirement for animal feeder layers, which maintain their pluripotency and self-renewal. hPSCs grown on animal feeder cells are at high risk for pathogen contamination and can be affected by the immunogenicity of the feeder layer. The presence of animal feeder cells also limits the scalability of hPSCs in culture because of the high cost of culturing and batch-to-batch variations. Therefore, development of feeder-free systems is imperative for robust, lower-cost, xeno-free, scalable culture of hPSCs. Biomaterials engineered with bioactive molecules such as adhesion proteins and extracellular matrix proteins, or synthetic materials such as peptides and polymers, may provide alternative substrates to animal feeder cells. This article reviews biomaterial-based, feeder-free systems for hPSC growth and maintenance, which provide clinically relevant alternatives to feeder cell systems.
