8 research outputs found

    Plasma-Corona-Processed Nanostructured Coating for Thermoregulative Textiles

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    A rapid increase in the atmospheric temperature has been reported in recent years worldwide. The lack of proper aid to protect from exposure to the sun during working hours has raised the number of sunburn cases among workers. It is important to promote productive workplaces without compromising safety and health concerns. In the present work, we report the low-temperature plasma (LTP)-assisted tailoring of the surface properties of fabrics to reflect IR radiation from the sun. The LTP technique can be adapted for thermally sensitive materials such as fabrics and textiles due to its lower working temperature range of 30 °C. We have modified various substrates such as commercially available fabric, regular, and boron nitride-incorporated electrospun PET surfaces with tetraethoxy orthosilicate (TEOS) plasma. TEOS plasma treatment can deposit a reactive plasma-polymerized silane nanolayer on the surface of these substrates. The plasma-processed silane nanolayer was systematically characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy, Keyence 3D-microscopic imaging, and transmission electron microscopy (TEM). From the SEM and TEM data, the size of the nanoparticles was observed in the range 100–200 nm. The thermal regulation coating thickness was examined with a Keyence 3D imaging technique. The IR reflection potential of the surface was analyzed by using an FLIR thermal imaging system. The data revealed that the plasma-modeled nanosurface shows higher reflective potential toward IR rays, and it seems to be cooler than the unprocessed surface by approximately 15 °C. The stability and efficiency of the plasma-modified electrospun nanolayer in water were satisfactorily examined with SEM and IR imaging. Taken together, these results suggest the excellent potential of plasma processing to develop IR reflective coatings

    Hemopressin-Based pH-Sensitive Hydrogel: A Potential Bioactive Platform for Drug Delivery

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    Peptides with proper sequences are capable of self-assembling into well-defined nanostructures, which can subsequently grow and entangle into three-dimensional nanomatrices. In this study, hemopressin, a cannabinoid receptor-modulating peptide derived from the α-chain of hemoglobin known to self-assemble into nanofibrils, was examined for its potential applicability as a gelator. The results indicated that hemopressin’s gel formation was dependent on pH and salt concentration. Although hemopressin’s macroscopic states showed differences, its microscopic structure remained largely unchanged in which it consisted mainly of the antiparallel β-sheet conformation as confirmed by FTIR (C=O stretch peaks at 1630 and 1695 cm<sup>–1</sup>) and CD (β-sheet peak at 195 nm). The major difference between the gel and sol states was displayed in the fibril length in which the gelation at pH 7.4 resulted in 4 μm fibrils, whereas the solution at pH 5.0 showed 800 nm fibrils. The pH-dependent sol–gel phase transition property was then utilized for the investigation of the pH-responsive release of FITC-dextran (4–40 kDa) from hemopressin fibrillary gel. Finally, the biocompatibility of the peptide was demonstrated by proliferation assay of cultured bone marrow mesenchymal stem cells. Altogether, the results suggested that hemopressin is a potentially promising candidate as a therapeutically active platform for drug delivery

    Immunostaining for phosphorylated Focal Adhesion Kinase.

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    <p>MSCs were seeded onto glass coverslips coated with electrospun nanofibers, or with FBS as a control. After 5 hours, cells were fixed and stained for phosphorylated Focal Adhesion Kinase (red). Cells were counterstained with DAPI to show cell nuclei (blue). Cells seeded onto PCL/col/HA scaffolds were better spread, and exhibited greater amounts of punctuate pFAK staining (site pY397) as compared with cells on PCL or PCL/HA. Cells seeded onto FBS-coated glass coverslips displayed pFAK staining in focal adhesion-type structures (white arrows), as expected for cells grown on 2D surfaces.</p

    Adsorption of FN and VN by electrospun scaffolds.

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    <p>Scaffolds were coated with fetal bovine serum (A), or implanted into rat tibial osteotomies for 30 min (B). Scaffolds were then washed to remove loosely bound proteins, and proteins were subsequently desorbed by incubation in boiling SDS-containing solution. The amounts of FN and VN were evaluated by Western blot.</p

    SEM images of MSCs cultured on nanofibrous scaffolds for 24 hours.

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    <p>A) Cell spreading was observed on PCL, PCL/HA, and PCL/col/HA scaffolds, but not on 100% collagen I (col). B) Col scaffolds (without cells) were incubated in culture media for 24 hrs to allow the potential release of soluble factors, and then the solution was collected. MSCs were suspended into this conditioned media, seeded onto PCL scaffolds, and allowed adhere in the media for 24 h. Under these conditions cell spreading was extensive, suggesting that lack of cell spreading on col substrates was not due to any soluble factors released from these scaffolds.</p

    Tensile Properties of dry and hydrated scaffolds.

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    <p>Values represent the average ± standard deviation calculated in the linear portion at 10% strain. The hydrated collagen scaffolds have very low mechanical properties and could not be measured by this technique.</p

    MTS assay quantifying cell proliferation on electrospun scaffolds of PCL, PCL/HA or PCL/col/HA.

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    <p>At day one, cell number was significantly higher on PCL/HA and PCL/col/HA scaffolds in comparison to PCL. By day four, PCL/HA was still significantly higher than PCL, and PCL/col/HA was significantly higher than PCL/HA and PCL. In addition, cell number on PCL/col/HA was significantly higher on day four than day one. An * denotes p<0.05</p

    Live cell imaging of GFP-expressing MSCs seeded onto electrospun scaffolds.

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    <p>A) Cells were seeded onto scaffolds and imaged over varying time points. Panels a–c: PCL scaffolds; panels d–f: PCL/HA scaffolds; panels g–i: PCL/col/HA scaffolds and panels j–l: col scaffolds. Scale bar = 100 µm. B) Higher magnification images of GFP-expressing MSCs at seven hours on electrospun scaffolds (panels m–p).</p
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