A straightforward process that enabled electrospinning of bioactive starch-based nanofiber scaffolds was developed by utilizing starch derived nano graphene oxide (nGO) as a property enhancer and formic acid as a solvent and esterification reagent. The reaction mechanism and process were followed by detailed spectroscopic investigation. Furthermore, the incorporation of nGO as a "green bioactive additive" endorsed starch nanofibrous scaffolds several advantageous functionalities including improved electrospinnability and thermal stability, good cytocompatibility, osteo-bioactivity, and retained biodegradability. The biodegradable starch/nGO nanofibers underwent simultaneous degradation and mineralization process during 1 week of cell culture and mineralization test, thus, mimicking the structure and function of extracellular matrices (ECMs) and indicating promise for bone tissue engineering applications.
Transparent wood (TW)-based composites are of significant interest for smart window applications. In this research, we demonstrate a facile dual-stimuli-responsive chromic TW where optical properties are reversibly controlled in response to changes in temperature and UV-radiation. For this functionality, bleached wood was impregnated with solvent-free thiol and ene monomers containing chromic components, consisting of a mixture of thermo-and photoresponsive chromophores, and was then UV-polymerized. Independent optical properties of individual chromic components were retained in the compositional mixture. This allowed to enhance the absolute optical transmission to 4 times above the phase change temperature. At the same time, the transmission at 550 nm could be reduced 11−77%, on exposure to UV by changing the concentration of chromic components. Chromic components were localized inside the lumen of the wood structure, and durable reversible optical properties were demonstrated by multiple cycling testing. In addition, the chromic TW composites showed reversible energy absorption capabilities for heat storage applications and demonstrated an enhancement of 64% in the tensile modulus as compared to a native thiol−ene polymer. This study elucidates the polymerization process and effect of chromic components distribution and composition on the material's performance and perspectives toward the development of smart photoresponsive windows with energy storage capabilities.
As a cost-effective
batch synthesis method, Si quantum dots (QDs)
with near-infrared photoluminescence, high quantum yield (>50%
in
polymer nanocomposite), and near-unity internal quantum efficiency
were fabricated from an inexpensive commercial precursor (triethoxysilane,
TES), using optimized annealing and etching processes. The optical
properties of such QDs are similar to those prepared from state-of-the-art
precursors (hydrogen silsesquioxane, HSQ) yet featuring an order of
magnitude lower cost. To understand the effect of synthesis parameters
on QD optical properties, we conducted a thorough comparison study
between common solid precursors: TES, HSQ, and silicon monoxide (SiO),
including chemical, structural, and optical characterizations. We
found that the structural nonuniformity and abundance of oxide inherent
to SiO limited the resultant QD performance, while for TES-derived
QDs this drawback can be avoided. The presented low-cost synthetic
approach would significantly favor applications requiring high loading
of good-quality Si QDs, such as light conversion for photovoltaics.
A versatile and convenient way to produce bioactive poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) electrospun nanofibrous scaffolds is described. PLA and PCL are extensively used as biocompatible scaffold materials for tissue engineering. Here, biobased nano graphene oxide dots (nGO) are incorporated in PLA or PCL electrospun scaffolds during the electrospinning process aiming to enhance the mechanical properties and endorse osteo-bioactivity. nGO was found to tightly attach to the fibers through secondary interactions. It also improved the electrospinnability and fiber quality. The prepared nanofibrous scaffolds exhibited enhanced mechanical properties, increased hydrophilicity, good cytocompatibility and osteo-bioactivity. Therefore, immense potential for bone tissue engineering applications is anticipated.
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