Nano Focus: Large-scale graphene gas barrier sets new record
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growth factors, signaling proteins, and extracellular matrix polymers) that contribute in concerted ways to direct stem cell fate. Progress, however, is being made, and Chandra and Lee survey this progressive research landscape. Specifically, Chandra and Lee’s review overviews and analyzes the results from more than 90 studies in which synthetic biomaterials have been applied to influence stem cell behavior. The authors
Schematic illustration of interactions between endogenous stem cells and synthetic microenvironment. Stem cells’ fate in a particular microenvironment is regulated by intricate reciprocal molecular interactions with its surroundings. Credit: Biomarker Insights.
discuss the roles of salient properties that affect a biomaterial’s performance as an artificial niche, including biocompatibility, drug release behavior, mechanical elasticity, surface chemistry, and surface topography. Current favored materials show promise, but require further optimization. For example, electrospun polymers—such as poly(lactic-co-glycolide)—can be fabricated with tunable growth factor release kinetics, but the nanoscale morphological features of such materials are difficult to control reliably (thus hampering simultaneous control over the role of surface topography on stem cell response). Due to the extensive combinatorial factors that influence stem cell proliferation and differentiation, the authors call for increased high throughput and computational studies as the field works toward a better understanding of extracellular matrix signals and their roles in controlling stem cell fate. However, despite the many lessons that remain ahead, the union of stem cells and engineered biomaterials holds great promise. Chandra and Lee emphasize this fact as they close their report by highlighting a variety of biomaterial-cell products that are currently under clinical development. Lukmaan Bawazer
A recent article from Georg Duesberg’s (Trinity College) laboratory, of which Wirtz is lead author, describes a novel large-scale graphene barrier that outperforms previously reported graphene barriers by a factor of 5000. The work is published in Advanced Materials Interfaces (DOI:10.1002/admi.201500082). Duesberg, Wirtz, and colleague Nina Berner (Trinity College) describe a highly effective oxygen gas barrier using stacks of chemical-vapor-deposited (CVD) graphene. A stack of three graphene layers (~5 cm2 surface area) transmitted just 1.10 × 10–17 cm3 cm/cm2 s (cm Hg) of oxygen, or 1.1 × 10–7 barrer, which is on par with most modern barriers, such as AlOx or SiOx. The oxygen and moisture barrier properties of graphene, coupled with its size and high
conductivity, make it an ideal candidate for a wide variety of applications, including flexible electronic displays and microelectronics packaging. The graphene barrier was prepared by stacking CVD-grown graphene onto a 150-μm polyethylene terephthalate (PET) substrate, a food packaging polymer that is known for good barrier properties. Unfortunately, “current CVD methods always have gr
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