Afeesh Rajan Unnithan

Wound-dressing materials with antibacterial activity from electrospun polyurethane-dextran nanofiber mats containing ciprofloxacin HCl.

Dextran is a versatile biomacromolecule for preparing electrospun nanofibrous membranes by blending with either water-soluble bioactive agents or hydrophobic biodegradable polymers for biomedical applications. In this study, an antibacterial electrospun scaffold was prepared by electrospinning of a solution composed of dextran, polyurethane (PU) and ciprofloxacin HCl (CipHCl) drug. The obtained nanofiber mats have good morphology. The mats were characterized by various analytical techniques. The interaction parameters between fibroblasts and the PU-dextran and PU-dextran-drug scaffolds such as viability, proliferation, and attachment were investigated. The results indicated that the cells interacted favorably with the scaffolds especially the drug-containing one. Moreover, the composite mat showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. Overall, our results conclude that the introduced scaffold might be an ideal biomaterial for wound dressing applications.

Electrospun antibacterial polyurethane-cellulose acetate-zein composite mats for wound dressing.

In this study, an antibacterial electrospun nanofibrous scaffolds with diameters around 400-700 nm were prepared by physically blending polyurethane (PU) with two biopolymers such as cellulose acetate (CA) and zein. Here, PU was used as the foundation polymer, was blended with CA and zein to achieve desirable properties such as better hydrophilicity, excellent cell attachment, proliferation and blood clotting ability. To prevent common clinical infections, an antimicrobial agent, streptomycin sulfate was incorporated into the electrospun fibers and its antimicrobial ability against the gram negative and gram positive bacteria were examined. The interaction between fibroblasts and the PU-CA and PU-CA-zein-drug scaffolds such as viability, proliferation, and attachment were characterized. PU-CA-zein-drug composite nanoscaffold showed enhanced blood clotting ability in comparison with pristine PU nanofibers. The presence of CA and zein in the nanofiber membrane improved its hydrophilicity, bioactivity and created a moist environment for the wound, which can accelerate wound recovery.

Mussel-Inspired Electrospun Nanofibers Functionalized with Size-Controlled Silver Nanoparticles for Wound Dressing Application

Electrospun nanofibers that contain silver nanoparticles (AgNPs) have a strong antibacterial activity that is beneficial to wound healing. However, most of the literature available on the bactericidal effects of this material is based on the use of AgNPs with uncontrolled size, shape, surface properties, and degree of aggregation. In this study, we report the first versatile synthesis of novel catechol moieties presenting electrospun nanofibers functionalized with AgNPs through catechol redox chemistry. The synthetic strategy allows control of the size and amount of AgNPs on the surface of nanofibers with the minimum degree of aggregation. We also evaluated the rate of release of the AgNPs, the biocompatibility of the nanofibers, the antibacterial activity in vitro, and the wound healing capacity in vivo. Our results suggest that these silver-releasing nanofibers have great potential for use in wound healing applications.

Laccase-poly(lactic-co-glycolic acid) (PLGA) nanofiber: Highly stable, reusable, and efficacious for the transformation of diclofenac

Nanobiocatalysis has received growing attention for use in commercial applications. We investigated the efficiency, stability, and reusability of laccase-poly(lactic-co-glycolic acid) (PLGA) nanofiber for diclofenac transformation. NH stretching vibrations (3400-3500 cm(-1) and 1560 cm(-1)) in FT-IR spectra confirmed immobilization of laccase on PLGA nanofibers. The relative activity of immobilized laccase was 82% that of free laccase. Immobilized laccase had better storage, pH, and thermal stability than free laccase. The immobilized laccase produced complete diclofenac transformation in three reuse cycles, which was extended to 6 cycles in the presence of syringaldehyde. Results suggest that laccase-PLGA nanofiber may be useful for removing diclofenac from aqueous sources and has potential for other commercial applications.

Electrospun polyurethane-dextran nanofiber mats loaded with Estradiol for post-menopausal wound dressing

Post-menopausal wound care management is a substantial burden on health services, since there are an increased number of elderly populations linked with age-related delayed wound healing. The controlled estrogen replacement can accelerate healing of acute cutaneous wounds, linked to its potent anti-inflammatory activity. The electrospinning technique can be used to introduce the desired therapeutic agents to the nanofiber matrix. So here we introduce a new material for wound tissue dressing, in which a polyurethane-dextran composite nanofibrous wound dressing material loaded with β-estradiol was obtained through electrospinning. Dextran can promote neovascularization and skin regeneration in chronic wounds. This study involves the characterization of these nanofibers and analysis of cell growth and proliferation to determine the efficiency of tissue regeneration on these biocomposite polymer nanofibrous scaffolds and to study the possibility of using it as a potential wound dressing material in the in vivo models.

Fabrication and characterization of electrospun zein/Ag nanocomposite mats for wound dressing applications

Wound dressing is a very important factor in the process of wound healing as proper wound care can accelerate the recovery of the wound. In this study, zein nanofibrous mats with fiber diameters around 350-500 nm were prepared by electrospinning and silver (Ag) nanoparticles around 20 nm were concurrently synthesized in situ into the mats. The electrospun nanofibers were characterized by Field Emission-Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. Cell viability and activity of fibroblasts cells in zein/Ag mats were also evaluated and results demonstrated good cytocompatibility and attachment of cells on the composite nanofibers. Also, the bactericidal activity of the fabricated mats against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli) was investigated via zone of inhibition test and results showed high anti-bacterial performance.

Multifunctional Nanocarpets for Cancer Theranostics: Remotely Controlled Graphene Nanoheaters for Thermo-Chemosensitisation and Magnetic Resonance Imaging

A new paradigm in cancer theranostics is enabled by safe multifunctional nanoplatform that can be applied for therapeutic functions together with imaging capabilities. Herein, we develop a multifunctional nanocomposite consisting of Graphene Oxide–Iron Oxide -Doxorubicin (GO-IO-DOX) as a theranostic cancer platform. The smart magnetic nanoplatform acts both as a hyperthermic agent that delivers heat when an alternating magnetic field is applied and a chemotherapeutic agent in a cancer environment by providing a pH-dependent drug release to administer a synergistic anticancer treatment with an enhanced T2 contrast for MRI. The novel GO-IO-DOX nanocomposites were tested in vitro and were observed to exhibit an enhanced tumoricidal effect through both hyperthermia and cancer cell-specific DOX release along with an excellent MRI performance, enabling a versatile theranostic platform for cancer. Moreover the localized antitumor effects of GO-IO-DOX increased substantially as a result of the drug sensitization through repeated application of hyperthermia.

An implantable smart magnetic nanofiber device for endoscopic hyperthermia treatment and tumor-triggered controlled drug release

UNLABELLED The study describes the design and synthesis of an implantable smart magnetic nanofiber device for endoscopic hyperthermia treatment and tumor-triggered controlled drug release. This device is achieved using a two-component smart nanofiber matrix from monodisperse iron oxide nanoparticles (IONPs) as well as bortezomib (BTZ), a chemotherapeutic drug. The IONP-incorporated nanofiber matrix was developed by electrospinning a biocompatible and bioresorbable polymer, poly (d,l-lactide-co-glycolide) (PLGA), and tumor-triggered anticancer drug delivery is realized by exploiting mussel-inspired surface functionalization using 2-(3,4-dihydroxyphenyl)ethylamine (dopamine) to conjugate the borate-containing BTZ anticancer drug through a catechol metal binding in a pH-sensitive manner. Thus, an implantable smart magnetic nanofiber device can be exploited to both apply hyperthermia with an alternating magnetic field (AMF) and to achieve cancer cell-specific drug release to enable synergistic cancer therapy. These results confirm that the BTZ-loaded mussel-inspired magnetic nanofiber matrix (BTZ-MMNF) is highly beneficial not only due to the higher therapeutic efficacy and low toxicity towards normal cells but also, as a result of the availability of magnetic nanoparticles for repeated hyperthermia application and tumor-triggered controlled drug release. STATEMENT OF SIGNIFICANCE The current work report on the design and development of a smart nanoplatform responsive to a magnetic field to administer both hyperthermia and pH-dependent anticancer drug release for the synergistic anticancer treatment. The iron oxide nanoparticles (IONPs) incorporated nanofiber matrix was developed by electrospinning a biocompatible polymer, poly (d,l-lactide-co-glycolide) (PLGA), and tumor-triggered anticancer drug delivery is realized by surface functionalization using 2-(3,4-dihydroxyphenyl)ethylamine (dopamine) to conjugate the boratecontaining anticancer drug bortezomib through a catechol metal binding in a pH-sensitive manner. This implantable magnetic nanofiber device can be exploited to apply hyperthermia with an alternating magnetic field and to achieve cancer cell-specific drug release to enable synergistic cancer therapy, which results in an improvement in both quality of life and patient compliance.

Electrospun polyurethane/Eudragit ® L100-55 composite mats for the pH dependent release of paclitaxel on duodenal stent cover application.

A nanofiber composite mat of PU and Eudragit(®) L100-55 was created using electrospinning process. The pH dependent release of paclitaxel was successfully done with the use of PU/EL100-55 nanocomposite mats as the controlling platform. The morphology of the nanofiber composites was surveyed using FESEM and ratios of the polymers affects the diameter of the nanofiber. Characterization of the nanofiber composite mat was done using FTIR, DSC-TGA method. The release rate of paclitaxel was determined and analyzed by in vitro drug release method. In order to mimic the condition of a human duodenum, the fibers were submersed on PBS of different pH levels (4.0, 6.0,) respectively, and then analyzed using high performance liquid chromatography (HPLC). Composite mats submersed in PBS with pH 4.0 showed lesser release profile compared to mats submersed in PBS with pH of 6.0. The composite mat has adequate mechanical properties and in vitro cell biocompatibility indicating that the material can be used for drug eluting stent cover application.

Activated carbon/silver-doped polyurethane electrospun nanofibers: Single mat for different pollutants treatment

AbstractAdsorption ability and antibacterial activity could be created in a single electrospun nanofiber mat. Activated carbon/silver-doped polyurethane electrospun nanofiber mats have been introduced as a novel multifunction nanostructural material. Production of the introduced mat could be achieved by electrospinning of a colloidal solution from polyurethane containing activated carbon nanoparticles and silver nitrate. The high electric field and the presence of N,N-dimethylformamide, which is used as a solvent, led to reduced silver precursor in the silver nanoparticles. The introduced mat revealed good adsorption ability toward methylene blue dye. The presence of silver nanoparticles resulted in good antibacterial activity for the introduced mat since a piece of the mat could completely eliminate Escherichia coli bacteria. Overall, according to the utilized physiochemical characterizations, the introduced mat can be used as a mask or filter media.