In-situ synthesis of AgNPs in the natural/synthetic hybrid nanofibrous scaffolds: Fabrication, characterization and antimicrobial activities

Maharjan, Bikendra,Joshi, Mahesh Kumar,Tiwari, Arjun Prasad,Park, Chan Hee,Kim, Cheol Sang Elsevier 2017 Journal of the mechanical behavior of biomedical m Vol.65 No.-

<P><B>Abstract</B></P> <P>Silver nanoparticles embedded within a nanofibrous polymer matrix have significant attention in recent years as an antimicrobial wound dressing materials. Herein, we have fabricated a novel Ag-polyurethane-zein hybrid nanofibrous scaffold for wound dressing applications. AgNPs were synthesized in-situ via reduction of silver nitrate in electrospinning solution. Varying mass composition of the components showed the pronounced effect on the morphology and physicochemical properties of the composite fibers. Field-Emission Scanning Electron Microscopy (FESEM) images revealed that PU and zein with mass ratio 2:1 produced the bead-free continuous and uniformly distributed nanofibers. Fourier-transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Thermogravimetric Analysis (TGA) confirmed the well interaction between component polymers. Compared to the pristine PU nanofibers, composite fibers showed enhanced tensile strength, young׳s modulus and surface wettability. The antibacterial capacity of the nanofibrous membrane was evaluated against gram-positive (<I>Staphylococcus aureus</I>) and gram-negative (<I>Escherichia coli</I>) bacterial strains via a zone of inhibition test, and the results showed high antibacterial performance for Ag incorporated composite mat. Experimental results of cell viability assay and microscopic imaging revealed that as-fabricated scaffolds have an excellent ability for fibroblast cell adhesion, proliferation and growth. Overall, as-fabricated antibacterial natural/synthetic composite scaffold can be a promising substrate for repairing skin defects.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel antibacterial natural/synthetic hybrid nanofibrous scaffold. </LI> <LI> Synthetization of AgNPs by in-situ reduction of silver nitrate in solution. </LI> <LI> Wettability and bioactivity of PU fiber improved by blending with biopolymer zein. </LI> <LI> Composite fibers showed enhanced tensile strength and young’s modulus. </LI> <LI> As-fabricated composite scaffold can be promising substrate for skin repairing. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Mussel-inspired elastic interpenetrated network hydrogel as an alternative for anti-thrombotic stent coating membrane

Obiweluozor, Francis O.,Maharjan, Bikendra,Gladys Emechebe, A.,Park, Chan Hee,Kim, Cheol Sang Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.347 No.-

<P><B>Abstract</B></P> <P>Coated stents are classified as new generation stents wrapped with a thin polymeric membrane for the treatment of numerous vascular irregularities ranging from aneurysms to vascular leaks. Compared to partially covered and bare metal stents (BMS), fully covered stents promote less tissue granulation and suppress thrombosis, and can be designed to be post-operative retrievable. Fabrication method and material selection play significant roles in coated stent application, due to commercially available coated stents induce some degree restenosis. We have successfully fabricated a non-thrombotic and biocompatible fully coated stent made of a semi-interpenetrating network (IPN) hydrogel composed of acrylic acid (AA), dopamine methacrylamide (DMA), and methyl methacrylate (MMA) terpolymer (P(AA-co-MMA-co-DMA)/PU, incorporated with polyurethane (PU). We utilize a conventional mold casting method to fabricate a uniform covered stent, with the stent struts fully embedded within the hydrogel membrane. Firm polymer-stent bonding was achieved by introducing DMA into the matrix. We characterized the membrane by conducting platelet adhesion/activation studies followed by hemolysis and inflammatory potential evaluation which supports a non-thrombogenicity of the P(AA-co-MMA-co-DMA)/PU semi-IPN hydrogel membrane. The quality of the coated hydrogel membrane was evaluated by scanning electron microscopy (SEM); mechanical stability of the layer was analyzed by peeling test; tensile test, and multiple physical deformations tests. Further evaluation will be carried out in the near future to evaluate the potential <I>in vivo</I> application of this new semi-IPN hydrogel coated stent to remedy non-vascular leaks and other strictures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Stent coating containing polydopamine to increase adhesion property was proposed. </LI> <LI> Incorporating PU as a second network greatly improve the mechanical property. </LI> <LI> The fabricated membrane create a stable coating that enable delivery with catheter. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Facile fabrication of spongy nanofibrous scaffold for tissue engineering applications

Hwang, Tae In,Maharjan, Bikendra,Tiwari, Arjun Prasad,Lee, Sunny,Joshi, Mahesh Kumar,Park, Chan Hee,Kim, Cheol Sang Elsevier 2018 Materials letters Vol.219 No.-

<P><B>Abstract</B></P> <P>Herein, we present a novel strategy to fabricate high porous fluffy type Poly (<SMALL>L</SMALL>-lactide) (PLA) nanofibrous scaffold for tissue regeneration. Low-density nanofibrous scaffold was fabricated by electrospinning the blend of PLA and lactic acid (LA), followed by selective leaching of LA. Digital images, Field Emission Scanning Electron Microscope (FE-SEM) images, Infra-red (IR) spectra, Thermogravimetric analysis (TGA) curves revealed the formation of the low density biomimetic nanofibrous mesh. <I>In vitro</I> cell compatibility results indicated that as-fabricated PLA nanofibrous scaffold enhanced the cell proliferation and growth compared to the corresponding two-dimensional nanofibrous scaffold. Furthermore, confocal microscopy images showed that cells seeded on the fluffy type nanofibrous mesh infiltrated throughout the depth of the scaffold, compared to no penetrating growth for the two-dimensional scaffold. The fabrication of such fascinating materials may provide new insights into the design and development of the low density nanofibrous scaffolds for various tissue engineering applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spongy and fluffy type nanofibrous scaffold is fabricated. </LI> <LI> Lactic acid assisted the formation of fluffy architecture. </LI> <LI> Cells were infiltrated throughout the scaffold on the fluffy type scaffold. </LI> <LI> Fluffy scaffold enhanced the cell proliferation and growth. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Cellulose reinforced nylon-6 nanofibrous membrane: Fabrication strategies, physicochemical characterizations, wicking properties and biomimetic mineralization

Joshi, Mahesh Kumar,Tiwari, Arjun Prasad,Maharjan, Bikendra,Won, Ko Sung,Kim, Han Joo,Park, Chan Hee,Kim, Cheol Sang Elsevier 2016 Carbohydrate polymers Vol.147 No.-

<P><B>Abstract</B></P> <P>The aim of the present study is to develop a facile, efficient approach to reinforce nylon 6 (N6) nanofibers with cellulose chains as well as to study the effect that cellulose regeneration has on the physicochemical properties of the composite fibers. Here, a cellulose acetate (CA) solution (17wt%) was prepared in formic acid and was blended with N6 solution (20%, prepared in formic acid and acetic acid) in various proportions, and the blended solutions were then electrospun to produce hybrid N6/CA nanofibers. Cellulose was regenerated in-situ in the fiber via alkaline saponification of the CA content of the hybrid fiber, leading to cellulose-reinforced N6 (N6/CL) nanofibers. Electron microscopy studies suggest that the fiber diameter and hence pore size gradually decreases as the mass composition of CA increases in the electrospinning solution. Cellulose regeneration showed noticeable change in the polymorphic behavior of N6, as observed in the XRD and IR spectra. The strong interaction of the hydroxyl group of cellulose with amide group of N6, mainly via hydrogen bonding, has a pronounced effect on the polymorphic behavior of N6. The γ-phase was dominant in pristine N6 and N6/CA fibers while α- phase was dominant in the N6/CL fibers. The surface wettability, wicking properties, and the tensile stress were greatly improved for N6/CL fibers compared to the corresponding N6/CA hybrid fibers. Results of DSC/TGA revealed that N6/CL fibers were more thermally stable than pristine N6 and N6/CA nanofibers. Furthermore, regeneration of cellulose chain improved the ability to nucleate bioactive calcium phosphate crystals in a simulated body fluid solution.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N6/CL composite fibers were obtained via electrospinning and deacetylation. </LI> <LI> Fiber diameter and pore size controlled varying the composition of component polymers. </LI> <LI> N6/CL composite fiber were more thermally stable than pristine N6 and N6/CA fibers. </LI> <LI> Wicking rate was pronouncedly enhanced due to cellulose regeneration. </LI> <LI> Tensile properties and biomimetic mineralization were improved. </LI> </UL> </P>

Synthesis and characterizations of activated carbon from Wisteria sinensis seeds biomass for energy storage applications

Ganesh Prasad Awasthi,Deval Prasad Bhattarai,Bikendra Maharjan,김경석,박찬희,김철상 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-

Herein, we proposed, for thefirst time, a novel activated carbon (AC) material synthesized from Wisteriasinensis (WS) seeds biomass. Characterizations of the material were carried out by Field-emissionscanning electron microscopy, Transmission electron microscopy, X-ray diffraction, Raman spectroscopy,Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller specific surface area analysis. As-synthesized AC was employed as an electrode material to evaluateits applicability in energy storage devices. Results showed enhanced capacitive performance in an acidicelectrolyte compared to the neutral electrolyte at similar current density. Thus, as-synthesized AC couldbe a suitable material for energy storage applications.

Formation of lipophilic drug-loaded human serum albumin nanofibers with the aid of glutathione

Tiwari, Arjun Prasad,Joshi, Mahesh Kumar,Maharjan, Bikendra,Lee, Joshua,Park, Chan Hee,Kim, Cheol Sang Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.313 No.-

<P><B>Abstract</B></P> <P>We report an efficient approach for the fabrication of hydrophobic drug-loaded human serum albumin nanofibers for the first time. The successful formation of nanofibers was found closely related to the glutathione (GSH) concentration, solution temperature, and heating time. As-fabricated nanofibers were characterized by electron microscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). The electron micrographs show that nanofibers have cylindrical morphology and diameters of 70–120nm and lengths of up to few micrometers with a smooth surface. GSH was found to contribute to the quicker unfolding of the HSA under high temperature (80–85°C) which resulted in the strong interaction with paclitaxel, leading to a morphological transformation from nanoparticles to nanofibers. In addition, the possible mechanisms of nanofiber formation have been discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hydrophobic drug (paclitaxel) loaded human serum albumin nanofiber is reported for the first time. </LI> <LI> Facile strategy to produce albumin fibers encapsulated with a hydrophobic drug. </LI> <LI> Glutathione concentration, solution temp, and heating time affected the nanofiber formation. </LI> <LI> Time-lapsed electron microscopy images confirmed three stages in fiber formation. </LI> <LI> Spherical particles evolved into cylindrical fibers in response to continuous heating. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Synthesis of polythiophene nanoparticles by surfactant-free chemical oxidative polymerization method: Characterization, in vitro biomineralization, and cytotoxicity evaluation

Deval Prasad Bhattarai,Ganesh Prasad Awasthi,Bikendra Maharjan,Joshua Lee,김범수,박찬희,김철상 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.77 No.-

Herein, we report the synthesis of polythiophene nanoparticles (PTh-NPs) by surfactant-free chemicaloxidative polymerization of thiophene at 37 C using ammonium persulphate as oxidant. PTh-NPssynthesized without surfactant were compared to those with surfactant in terms of surface morphology,crystallinity, cytotoxicity and some other aspects. Thermogravimetric analysis showed a good thermalstability of as-synthesized PTh-NPs. In vitro biomineralization revealed the nucleation of calcium andphosphate onto the NPs. Cytotoxicity of PTh-NPs was evaluated by measuring cell viability of preosteoblastMC3T3-E1 and PC12 cell lines. PTh-NPs synthesized without using surfactant exhibited bettercell viability compared to those with surfactant.

pH/NIR-Responsive Polypyrrole-Functionalized Fibrous Localized Drug-Delivery Platform for Synergistic Cancer Therapy

Tiwari, Arjun Prasad,Hwang, Tae In,Oh, Jung-Mi,Maharjan, Bikendra,Chun, Sungkun,Kim, Beom Su,Joshi, Mahesh Kumar,Park, Chan Hee,Kim, Cheol Sang American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.24

<P>Localized drug-delivery systems (LDDSs) are a promising approach for cancer treatment because they decrease systematic toxicity and enhance the therapeutic effect of the drugs via site-specific delivery of active compounds and possible gradual release. However, the development of LDDS with rationally controlled drug release and intelligent functionality holds great challenge. To this end, we have developed a tailorable fibrous site-specific drug-delivery platform functionalized with pH- and near-infrared (NIR)-responsive polypyrrole (PPy), with the aim of cancer treatment via a combination of photothermal ablation and chemotherapy. First, a paclitaxel (PTX)-loaded polycaprolactone (PCL) (PCL-PTX) mat was prepared by electrospinning and subsequently in situ membrane surface-functionalized with different concentrations of PPy. The obtained PPy-functionalized mats exhibited excellent photostability and heating property in response to NIR exposure. PPy-coated mats exhibited enhanced PTX release in a pH 5.5 environment compared to pH 7.4. Release was further accelerated in response to NIR under both conditions; however, superior release was observed at pH 5.5 compared to pH 7.4, indicating a dual stimuli-responsive (pH and NIR) drug-delivery platform. More importantly, the 808 nm NIR irradiation enabled markedly accelerated PTX release from PPy-coated PCL-PTX mats and slowed and sustained release following termination of laser irradiation, confirming representative stepwise drug-release properties. PPy-coated PCL-PTX mats presented significantly enhanced in vitro and in vivo anticancer efficacy under NIR irradiation compared to PPy-coated PCL-PTX mats not exposed to NIR or uncoated mats (PCL-PTX). This study has thus developed a promising fibrous site-specific drug-delivery platform with NIR- and pH-triggering that notably utilizes PPy as a dopant for synergistic photothermal chemotherapy.</P> [FIG OMISSION]</BR>

Lactic acid assisted fabrication of bioactive three-dimensional PLLA/β-TCP fibrous scaffold for biomedical application

Lee, Sunny,Joshi, Mahesh Kumar,Tiwari, Arjun Prasad,Maharjan, Bikendra,Kim, Kyung Suk,Yun, Yeo-Heung,Park, Chan Hee,Kim, Cheol Sang Elsevier 2018 Chemical engineering journal Vol.347 No.-

<P><B>Abstract</B></P> <P>Low-density, high porous bioactive fibrous scaffolds have attracted significant attention for tissue engineering. However, fabrication of biomimetic fibrous scaffolds having three-dimensional architecture along with bioactive materials still remains a challenging task for biomaterial scientists. Herein, for the first time, we developed a novel strategy to fabricate highly porous ß-tricalcium phosphate (ß-TCP) incorporated Poly (<SMALL>L</SMALL>-lactide) (PLLA) fibrous scaffold for bone tissue engineering. Blending of PLLA with its monomer, lactic acid (LA) produced the fluffy type highly porous nanofibrous mesh. The mass composition of the constituents of the blend solution was varied to control the morphology and packing of the nanofibers in the scaffold. The results showed that LA played the vital role in the generation of the 3D fluffy type fibrous mesh. ß-TCP particles were incorporated in the blend solution prior to the electrospinning solution, to fabricate ß-TCP incorporated PLLA fibrous scaffold. Later, LA was leached out by washing with distilled water, to avoid its adverse effect on biocompatibility. Digital and SEM images revealed the formation of spongy, low-density fibrous mesh. TEM images, IR, and TGA analysis confirmed the presence of ß-TCP nanoparticles in the nanofibers after leaching of LA. Incorporation of the ß-TCP enhanced the water uptake ability, <I>in vitro</I> bio-mineralization, and bioactivity of the fibrous scaffold. Confocal microscopy images showed that the pre-osteoblast cells seeded on the fluffy type fibrous mesh infiltrated throughout the depth of the scaffold, compared to no penetrating growth for the 2D scaffold. <I>In vitro</I> biocompatibility evaluated by CCK assay showed significantly higher growth for cells on the fluffy type scaffold, compared to the 2D scaffold. We demonstrated scaffolds suitability for biocompatibility and osteogenic differentiation of hMSCs as well. We believe that the fabrication of bioactive particle incorporated highly porous 3D fibrous scaffold will open a new avenue for tissue engineering applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3-Dimensional novel biofunctional fluffy-type fiber was reported. </LI> <LI> Lactic acid was found to have a key role for formation. </LI> <LI> Ratio of PLLA/LA determines packing and morphology of fiber. </LI> <LI> Fluffy type fibrous mesh greatly improved the swelling properties, biomimetic mineralization, cell infiltration and growth. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Heterogeneous electrospun polycaprolactone/polyethylene glycol membranes with improved wettability, biocompatibility, and mineralization

Tiwari, Arjun Prasad,Joshi, Mahesh Kumar,Lee, Joshua,Maharjan, Bikendra,Ko, Sung Won,Park, Chan Hee,Kim, Cheol Sang Elsevier 2017 Colloids and surfaces. A, Physicochemical and engi Vol.520 No.-

<P><B>Abstract</B></P> <P>Polycaprolactone (PCL) based electrospun membranes possess many favorable characteristics such as flexibility, high mechanical properties, and non-toxicity, all of which are required for tissue engineering applications. However, their hydrophobic nature and low biocompatibility limit their uses. To overcome these drawbacks, we propose highly biocompatible and hydrophilic heterogeneous scaffolds from a blend of PCL with polyethylene glycol (PEG) that is composed of nano-nets along with backbone/main fibers via an electro-spinning/netting (ESN) technique. Different scaffolds were fabricated by varying the mass composition of PCL to PEG and evaluated physicochemically and biologically. Scanning electron microscopy showed that the PCL/PEG membranes were of a bimodal structure consisting of backbone/main fibers (diameter range=350–600nm) and ultrathin nano-nets while the pure PCL mat was composed of only backbone fibers (diameter range=550–800nm). The nano-nets were composed of ultrathin nano-wires with an average diameter of 10–20nm, shaped in a hexagonal form. We have also prepared the PCL/PEG membranes without nano-nets and compared them to heterogeneous membranes in order to describe the effect of the nano-nets by well distinguishing the effect of PEG on tissue engineering applications such as wettability, biocompatibility, and biomineralization. The results showed that heterogeneous scaffolds exhibit enhanced wettability, mechanical stability, biocompatibility, and mineralization compared to pure PCL and PCL/PEG scaffolds without nano-nets, which confirmed that the nano-nets in the membranes had positive effects for tissue engineering applications. Findings from this study have revealed that the heterogeneous fibrous membrane could be useful in the design and tailoring of a suitable structure as a scaffold for bone tissue engineering.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Heterogeneous fibrous membrane was reported from PCL/PEG first time via electro-spinning/netting (ESN). </LI> <LI> Heterogeneous membrane was consisting of thicker/backbone fibers and ultrathin nano-nets. </LI> <LI> Hydrophilicity and mineralization were improved with incorporation of PEG into PCL fibers. </LI> <LI> Heterogeneous scaffolds showed better support for cell activities. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>