15 research outputs found
Eco-Friendly Silica Microcapsules with Improved Fragrance Retention
Microcapsules are employed extensively in various applications; however, most are composed of synthetic plastics. Thus, substitution of their component materials is essential to prevent environmental problems associated with primary microplastics. Herein, we report the synthesis of eco-friendly silica core–shell microcapsules for fragrance retention. The silica shell was prepared via oil/water emulsion template synthesis using tetraethyl orthosilicate (TEOS), which was added to the immature silica microcapsules prior to complete formation of primary silica shells to promote seeded growth for further reaction of silica. The thickness of the silica shell increased from 42.29 to 70.03 nm, while the Brunauer–Emmett–Teller surface area and internal pore area decreased from 155.16 and 30.08 m2/g to 92.28 and 5.36 m2/g, respectively. The silica microcapsules with lower surface areas retained fragrance for more than 80 days, even in a harsh environment of 15% sodium dodecyl sulfate at 60 °C, whereas the fragrance compound in those without additional TEOS treatment was completely released within seven days. Practical qualitative evaluation of fragrance was also performed for application in fragrance delivery because of the enhanced long-term fragrance retention ability. Our findings show the widespread potential of microcapsules synthesized from eco-friendly materials in industrial applications
Eco-Friendly Silica Microcapsules with Improved Fragrance Retention
Microcapsules are employed extensively in various applications; however, most are composed of synthetic plastics. Thus, substitution of their component materials is essential to prevent environmental problems associated with primary microplastics. Herein, we report the synthesis of eco-friendly silica core–shell microcapsules for fragrance retention. The silica shell was prepared via oil/water emulsion template synthesis using tetraethyl orthosilicate (TEOS), which was added to the immature silica microcapsules prior to complete formation of primary silica shells to promote seeded growth for further reaction of silica. The thickness of the silica shell increased from 42.29 to 70.03 nm, while the Brunauer–Emmett–Teller surface area and internal pore area decreased from 155.16 and 30.08 m2/g to 92.28 and 5.36 m2/g, respectively. The silica microcapsules with lower surface areas retained fragrance for more than 80 days, even in a harsh environment of 15% sodium dodecyl sulfate at 60 °C, whereas the fragrance compound in those without additional TEOS treatment was completely released within seven days. Practical qualitative evaluation of fragrance was also performed for application in fragrance delivery because of the enhanced long-term fragrance retention ability. Our findings show the widespread potential of microcapsules synthesized from eco-friendly materials in industrial applications
Low Subthreshold Slope AlGaN/GaN MOS-HEMT with Spike-Annealed HfO2 Gate Dielectric
AlGaN/GaN metal-oxide semiconductor high electron mobility transistors (MOS-HEMTs) with undoped ferroelectric HfO2 have been investigated. Annealing is often a critical step for improving the quality of as-deposited amorphous gate oxides. Thermal treatment of HfO2 gate dielectric, however, is known to degrade the oxide/nitride interface due to the formation of Ga-containing oxide. In this work, the undoped HfO2 gate dielectric was spike-annealed at 600 °C after the film was deposited by atomic layer deposition to improve the ferroelectricity without degrading the interface. As a result, the subthreshold slope of AlGaN/GaN MOS-HEMTs close to 60 mV/dec and on/off ratio>109 were achieved. These results suggest optimizing the HfO2/nitride interface can be a critical step towards a low-loss high-power switching device
In Situ Supramolecular Assembly and Modular Modification of Hyaluronic Acid Hydrogels for 3D Cellular Engineering
A facile In situ supramolecular assembly and modular modification of biocompatible hydrogels were demonstrated using cucurbit[6]uril-conjugated hyaluronic add (CB[6]-HA), diaminohexane-conjugated HA (DAH-HA), and tags-CB[6] for cellular engineering applications. The strong and selective host-guest interaction between (KM and DAH made possible the supramolecular assembly of CB[6]/DAH-HA hydrogels In the presence of cells. Then, the 3D environment of CB[6]/DAH-HA hydrogels was modularly modified by the simple treatment with various multifunctional tags-CB[6]. Furthermore, we could confirm in situ formation of CB[6]/DAH-HA hydrogels under the skin of nude mice by sequential subcutaneous injections of CB[6]-HA and DAH-HA solutions. The fluorescence of modularly modified fluorescein isothiocyanate (FITC)-CB[6] In the hydrogels was maintained for up toll days, reflecting the feasibility to deliver the proper cues for cellular proliferation and differentiation In the body. Taken together, CB[6]/DAH-HA hydrogels might be successfully exploited as a 3D artificial extracellular matrix for various tissue engineering applications.X11122112sciescopu
3D Tissue Engineered Supramolecular Hydrogels for Controlled Chondrogenesis of Human Mesenchymal Stem Cells
Despite a wide investigation of hydrogels as an
artificial extracellular matrix, there are few scaffold systems for
the facile spatiotemporal control of mesenchymal stem cells
(MSCs). Here, we report 3D tissue engineered supramolecular
hydrogels prepared with highly water-soluble monofunctionalized
cucurbit[6]uril−hyaluronic acid (CB[6]-HA), diaminohexane
conjugated HA (DAH-HA), and drug conjugated
CB[6] (drug-CB[6]) for the controlled chondrogenesis of
human mesenchymal stem cells (hMSCs). The mechanical
property of supramolecular HA hydrogels was modulated by
changing the cross-linking density for the spatial control of hMSCs. In addition, the differentiation of hMSCs was temporally
controlled by changing the release profiles of transforming growth factor-β3 (TGF-β3) and/or dexamethasone (Dexa) from the
hydrolyzable Dexa-CB[6]. The effective chondrogenic differentiation of hMSCs encapsulated in the monoCB[6]/DAH-HA
hydrogel with TGF-β3 and Dexa-CB[6] was confirmed by biochemical glycosaminoglycan content analysis, real-time quantitative
PCR, histological, and immunohistochemical analyses. Taken together, we could confirm the feasibility of cytocompatible
monoCB[6]/DAH-HA hydrogels as a platform scaffold with controlled drug delivery for cartilage regeneration and other various
tissue engineering applications.145451sciescopu
<i>In Situ</i> Supramolecular Assembly and Modular Modification of Hyaluronic Acid Hydrogels for 3D Cellular Engineering
A facile <i>in situ</i> supramolecular assembly and modular modification of biocompatible hydrogels were demonstrated using cucurbit[6]uril-conjugated hyaluronic acid (CB[6]-HA), diaminohexane-conjugated HA (DAH-HA), and tags-CB[6] for cellular engineering applications. The strong and selective host–guest interaction between CB[6] and DAH made possible the supramolecular assembly of CB[6]/DAH-HA hydrogels in the presence of cells. Then, the 3D environment of CB[6]/DAH-HA hydrogels was modularly modified by the simple treatment with various multifunctional tags-CB[6]. Furthermore, we could confirm <i>in situ</i> formation of CB[6]/DAH-HA hydrogels under the skin of nude mice by sequential subcutaneous injections of CB[6]-HA and DAH-HA solutions. The fluorescence of modularly modified fluorescein isothiocyanate (FITC)-CB[6] in the hydrogels was maintained for up to 11 days, reflecting the feasibility to deliver the proper cues for cellular proliferation and differentiation in the body. Taken together, CB[6]/DAH-HA hydrogels might be successfully exploited as a 3D artificial extracellular matrix for various tissue engineering applications
<i>In Situ</i> Supramolecular Assembly and Modular Modification of Hyaluronic Acid Hydrogels for 3D Cellular Engineering
A facile <i>in situ</i> supramolecular assembly and modular modification of biocompatible hydrogels were demonstrated using cucurbit[6]uril-conjugated hyaluronic acid (CB[6]-HA), diaminohexane-conjugated HA (DAH-HA), and tags-CB[6] for cellular engineering applications. The strong and selective host–guest interaction between CB[6] and DAH made possible the supramolecular assembly of CB[6]/DAH-HA hydrogels in the presence of cells. Then, the 3D environment of CB[6]/DAH-HA hydrogels was modularly modified by the simple treatment with various multifunctional tags-CB[6]. Furthermore, we could confirm <i>in situ</i> formation of CB[6]/DAH-HA hydrogels under the skin of nude mice by sequential subcutaneous injections of CB[6]-HA and DAH-HA solutions. The fluorescence of modularly modified fluorescein isothiocyanate (FITC)-CB[6] in the hydrogels was maintained for up to 11 days, reflecting the feasibility to deliver the proper cues for cellular proliferation and differentiation in the body. Taken together, CB[6]/DAH-HA hydrogels might be successfully exploited as a 3D artificial extracellular matrix for various tissue engineering applications