Research interest in boron nitride nanotubes (BNNTs) has increased after the recent success of large-scale BNNT syntheses using high-temperature-pressure laser ablation or high-temperature plasma ...methods. Nonetheless, there are limits to the application and commercialization of these materials because of the difficulties associated with their fine structural control. Herein, the growth kinetics of BNNTs were systemically studied for this purpose. The growth pressure of the nitrogen feed gas was varied while the growth temperature remained constant, which was confirmed by black body radiation measurements and calculations based on a heat loss model. Changing from the diffusion-limited regime to the supply-limited regime of growth kinetics based on the optimized BNNT synthesis condition afforded the control of the number of BNNT walls. The total amount of BNNTs possessing single and double walls was over 70%, and the BNNT surface area increased to 278.2 m
/g corresponding to small wall numbers and diameters. Taking advantage of the large surface area and high-temperature durability of the material, BNNTs utilized as a recyclable adsorbent for water purification. The efficiency of the BNNTs for capturing methylene blue particles in water was approximately 94%, even after three repetition cycles, showing the potential of the material for application in the filter industry.
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A highly electroactive bio-nanohybrid film of polypyrrole (PPy)-Nafion (Nf)-functionalized multi-walled carbon nanotubes (fMWCNTs) nanocomposite was prepared on the glassy carbon ...electrode (GCE) by a facile one-step electrochemical polymerization technique followed by chitosan-glucose oxidase (CH-GOx) immobilization on its surface to achieve a high-performance glucose biosensor. The as-fabricated nanohybrid composite provides high surface area for GOx immobilization and thus enhances the enzyme-loading efficiency. The structural characterization revealed that the PPy-Nf-fMWCNTs nanocomposite films were uniformly formed on GCE and after GOx immobilization, the surface porosities of the film were decreased due to enzyme encapsulation inside the bio-nanohybrid composite materials. The electrochemical behavior of the fabricated biosensor was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and amperometry measurements. The results indicated an excellent catalytic property of bio-nanohybrid film for glucose detection with improved sensitivity of 2860.3μAmM−1cm−2, the linear range up to 4.7mM (R2=0.9992), and a low detection limit of 5μM under a signal/noise (S/N) ratio of 3. Furthermore, the resulting biosensor presented reliable selectivity, better long-term stability, good repeatability, reproducibility, and acceptable measurement of glucose concentration in real serum samples. Thus, this fabricated biosensor provides an efficient and highly sensitive platform for glucose sensing and can open up new avenues for clinical applications.
Some polypeptide N-acetyl-galactosaminyltransferases (GALNTs) are associated with cancer, but their function in organ-specific metastasis remains unclear. Here, we report that GALNT14 promotes breast ...cancer metastasis to the lung by enhancing the initiation of metastatic colonies as well as their subsequent growth into overt metastases. Our results suggest that GALNT14 augments the self-renewal properties of breast cancer cells (BCCs). Furthermore, GALNT14 overcomes the inhibitory effect of lung-derived bone morphogenetic proteins (BMPs) on self-renewal and therefore facilitates metastasis initiation within the lung microenvironment. In addition, GALNT14 supports continuous growth of BCCs in the lung by not only inducing macrophage infiltration but also exploiting macrophage-derived fibroblast growth factors (FGFs). Finally, we identify KRAS-PI3K-c-JUN signalling as an upstream pathway that accounts for the elevated expression of GALNT14 in lung-metastatic BCCs. Collectively, our findings uncover an unprecedented role for GALNT14 in the pulmonary metastasis of breast cancer and elucidate the underlying molecular mechanisms.
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•A uniform surface topography of titanium nanotubes (TNTs) were fabricated through anodization.•The TNTs were coated with polyaniline (PANI) via cyclic voltammetric technique.•The ...bioinspired TNTs/PANI showed an effective antibacterial property.•Highly biocompatible TNTs/PANI scaffolds enhanced the proliferation of pre-osteoblast cells.
In this work, titanium oxide nanotubes (TNTs) have been developed via electrochemical anodization process, followed by potentiostatic electropolymerization of aniline monomer to achieve TNTs coated polyaniline (PANI) substrate using cyclic voltammetry method at low temperature. Prior to PANI decoration, crystallinity of titanium oxide nanotubes (TNTs) was obtained by annealing the substrate at 420 °C for two hours. The physicochemical characterization of the as-prepared TNTs and TNTs/PANI were analyzed using FE-SEM, AFM, XRD and FT-IR techniques. A coating of PANI forms a sheath around the nanotubes and protects them from metallic corrosion. Large surface area to volume ratio of TNTs showed improved properties in biocompatibility, thermal stability, electrical conductivity, biomineralization and hydrophilicity after coating with PANI, an electroactive conducting polymer. In addition, the TNTs/PANI exhibited an effective platform to enhance attachment, development and proliferation of preosteoblast (MC3T3-E1) cells which opens a new avenue in the realm of bone tissue engineering. The cells’ morphology to their surrounding topography, development, or proliferation, and osteogenic-related markers (such as ALP increased level, collagen type I secretion) were also analysed. Such types of surface modification tailoring on titanium nanotubes could offer a potential and a promising scaffold material for biomedical implantation in bone tissue engineering.
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•Gas foaming technique is applied to prepare a 3-D nanofibrous scaffold.•Sodium borohydride solution is introduced as gas foaming reagent.•Novel mechanism for in situ gas foaming is ...demonstrated.•Nature of the polymers affects the fabrication process.
In the past decade, considerable efforts have been made to fabricate the biomimetic scaffolds from electrospun nanofibers for tissue engineering applications. However, one of the major concerns with electrospun nanofibrous scaffolds is the densely packed fibers in two-dimensional (2-D) array which impedes their applicability in tissue regeneration. To overcome this problem, a simple and facile post-electrospinning procedure was developed to modify a densely packed 2-D electrospun membrane into low density three-dimensional (3-D) scaffolds. In this strategy, an electrospun nanofibrous mat was immersed in a sodium borohydride (SB) solution. The interconnected pores of a mat are filled with the SB solution driven by capillary forces where it undergoes hydrolysis to produce hydrogen gas. The in situ generated gas molecules form clusters to minimize the free energy resulting in pore nucleation that reorganizes the nanofibers to form a low density, macroporous, spongy and multi-layered 3-D scaffold. Electrospun mats of various polar and non-polar polymers were subjected to post-electrospinning process to monitor the fabrication process. It has been found that the solvent for sodium borohydride (either water or methanol) played a crucial role in post-electrospinning process. Only the electrospun mat of polar polymers were amended into 3-D architecture using aqueous SB solution while methanol solution was found equally effective for both polar and non-polar polymers. Moreover, the fabrication process was fast in methanol solution compared to an aqueous solution due to the rapid liberation of hydrogen gas from the methanolysis reaction compared to the hydrolysis reaction. This process will reveal a new approach for the fabrication of a three-dimensional, low-density, nanofibrous materials for biomedical and industrial applications using a wide variety of polymers.
In approximately 20% of patients with superficial bladder tumors, the tumors progress to invasive tumors after treatment. Current methods of predicting the clinical behavior of these tumors ...prospectively are unreliable. We aim to identify a molecular signature that can reliably identify patients with high-risk superficial tumors that are likely to progress to invasive tumors.
Gene expression data were collected from tumor specimens from 165 patients with bladder cancer. Various statistical methods, including leave-one-out cross-validation methods, were applied to identify a gene expression signature that could predict the likelihood of progression to invasive tumors and to test the robustness of the expression signature in an independent cohort. The robustness of the gene expression signature was validated in an independent (n = 353) cohort.
Supervised analysis of gene expression data revealed a gene expression signature that is strongly associated with invasive bladder tumors. A molecular classifier based on this gene expression signature correctly predicted the likelihood of progression of superficial tumor to invasive tumor.
We present a molecular signature that can predict, at diagnosis, the likelihood of bladder cancer progression and, possibly, lead to improvements in patient therapy.
•A single mat having varieties of performance for water treatment is simply introduced.•Cost effective Ag-doped fly ash/PU nanofibers are fabricated in one-step.•Solvent reduction of AgNO3 could ...produce Ag-loaded spider-web nets.•Size of Ag NPs on fiber surface can be controlled by controlling stirring time.•Fabrication of nanocomposite using pollutant material to control other pollutents.
A stable silver-doped fly ash/polyurathene (Ag-FA/PU) nanocomposite multifunctional membrane is prepared by a facile one-step electrospinning process using fly ash particles (FAPs). Colloidal solution of PU with FAPs and Ag metal precursor was subjected to fabricate nanocomposite spider-web-like membrane using electrospinning process. Presence of N,N-dimethylformamide (solvent of PU) led to reduce silver nitrate into Ag NPs. Incorporation of Ag NPs and FAPs through electrospun PU fibers is proven through electron microscopy and spectroscopic techniques. Presence of these NPs on PU nanofibers introduces several potential physicochemical properties such as spider-web-like nano-neeting for NPs separation, enhanced absorption capacity to remove carcinogenic arsenic (As) and toxic organic dyes, and antibacterial properties with reduce bio-fouling for membrane filter application. Preliminary observations used for above-mentioned applications for water treatment showed that it will be an economically and environmentally friendly nonwoven matrix for water purification. This simple approach highlights new avenues about the utilization of one pollutant material to control other pollutants in scalable and inexpensive ways.
Background
Current design strategies for small diameter vascular grafts (< 6 mm internal diameter; ID) are focused on mimicking native vascular tissue because the commercially available grafts still ...fail at small diameters, notably due to development of intimal hyperplasia and thrombosis. To overcome these challenges, various design approaches, material selection, and surface modification strategies have been employed to improve the patency of small-diameter grafts.
Review
The purpose of this review is to outline various considerations in the development of small-diameter vascular grafts, including material choice, surface modifications to enhance biocompatibility/endothelialization, and mechanical properties of the graft, that are currently being implanted. Additionally, we have taken into account the general vascular physiology, tissue engineering approaches, and collective achievements of the authors in this area. We reviewed both commercially available synthetic grafts (e-PTFE and PET), elastic polymers such as polyurethane and biodegradable and bioresorbable materials. We included naturally occurring materials by focusing on their potential application in the development of future vascular alternatives.
Conclusion
Until now, there are few comprehensive reviews regarding considerations in the design of small-diameter vascular grafts in the literature. Here-in, we have discussed in-depth the various strategies employed to generate engineered vascular graft due to their high demand for vascular surgeries. While some TEVG design strategies have shown greater potential in contrast to autologous or synthetic ePTFE conduits, many are still hindered by high production cost which prevents their widespread adoption. Nonetheless, as tissue engineers continue to develop on their strategies and procedures for improved TEVGs, soon, a reliable engineered graft will be available in the market. Hence, we anticipate a viable TEVG with resorbable property, fabricated
via
electrospinning approach to hold a greater potential that can overcome the challenges observed in both autologous and allogenic grafts. This is because they can be mechanically tuned, incorporated/surface-functionalized with bioactive molecules and mass-manufactured in a reproducible manner. It is also found that most of the success in engineered vascular graft approaching commercialization is for large vessels rather than small-diameter grafts used as cardiovascular bypass grafts. Consequently, the field of vascular engineering is still available for future innovators that can take up the challenge to create a functional arterial substitute.
•Electrospun cellulose acetate mat was fabricated and saponified to regenerate cellulose.•2D cellulose mat was modified into 3D spongy structure using a gas foaming technique.•Large pore and thin ...layered structure of 3D cellulose sponge allowed cell infiltration and growth.•The 3D cellulose sponge showed the better hydroxyapatite nucleation ability.•Calcium deficient Ca–P is deposited on the surface of the nanofiber.
In this study, cellulose based scaffolds were produced by electrospinning of cellulose acetate (CA) solution followed by its saponification with NaOH/ethanol system for 24h. The resulting nonwoven cellulose mat was treated with sodium borohydride (SB) solution. In situ hydrolysis of SB solution into the pores of the membrane produced hydrogen gas resulting a three-dimensional (3D) cellulose sponge. SEM images demonstrated an open porous and loosely packed fibrous mesh compared to the tightly packed single-layered structure of the conventional electrospun membrane. 3D cellulose sponge showed admirable ability to nucleate bioactive calcium phosphate (Ca–P) crystals in simulated body fluid (SBF) solution. SEM-EDX and X-ray diffraction studies revealed that the minerals deposited on the nanofibers have the nonstoichiometric composition similar to that of hydroxyapatite, the mineralized component of the bone. 3D cellulose sponge exhibited the better cell infiltration, spreading and proliferation compared to 2D cellulose mat. Therefore, a facile fabrication of 3D cellulose sponge with improved mineralization represents an innovative strategy for the bone tissue engineering applications.
A multifunctional hydrogel that combines the dual functionality of both antifouling and antimicrobial capacities holds great potential for many bioapplications. Many approaches and different ...materials have been employed to synthesize such a material. However, a systematic study, including in vitro and in vivo evaluation, on such a material as wound dressings is highly scarce at present. Herein, we report on a new strategy that uses catecholic chemistry to synthesize antimicrobial silver nanoparticles impregnated into antifouling zwitterionic hydrogels. For this purpose, hydrophobic dopamine methacrylamide monomer (DMA) was mixed in an aqueous solution of sodium tetraborate decahydrate and DMA monomer became soluble after increasing pH to 9 due to the complexation between catechol groups and boron. Then, cross-linking polymerization of zwitterionic monomer was carried out with the solution of the protected dopamine monomer to produce a new hydrogel. When this new hydrogel comes in contact with a silver nitrate solution, silver nanoparticles (AgNPs) are formed in its structure as a result of the redox property of the catechol groups and in the absence of any other external reducing agent. The results obtained from TEM and XRD measurements indicate that AgNPs with diameters of around 20 nm had formed within the networks. FESEM images confirmed that the silver nanoparticles were homogeneously incorporated throughout the hydrogel network, and FTIR spectroscopy demonstrated that the catechol moiety in the polymeric backbone of the hydrogel is responsible for the reduction of silver ions into the AgNPs. Finally, the in vitro and in vivo experiments suggest that these mussel-inspired, antifouling, antibacterial hydrogels have great potential for use in wound healing applications.
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