Antibacterial, cytotoxicity and biodegradability studies of polycaprolactone nanofibers holding green synthesized Ag nanoparticles using atropa belladonna extract.

Atropa belladonna is one of the herbs used to treat wounds and prevent inflammation. This study provides a scientific assessment for the wound healing potential of biodegradable nanofibers containing Ag nanoparticles encapsulated with atropa belladonna extract (eAgNPs). Ultraviolet-visible (UV-vis) spectroscopy was used to observe the localized surface plasmon resonance (LSPR) band of AgNPs synthesized from atropa belladonna extract prepared under different conditions. Polycaprolactone (PCL) nanofibers with eAgNPs were fabricated using the electrospinning technique. The distribution of AgNPs and eAgNPs and the size of nanofibers were characterized with scanning and transmission electron microscopy (SEM, TEM) before and after degradation at the end of 18 weeks. Fourier transform infrared (FTIR) spectroscopy showed the surface interactivity between AgNPs, atropa belladonna extract and PCL nanofibers and also approved the modification of PCL nanofibers with eAgNPs. X-ray diffraction analysis (XRD) defined the formation of the crystalline AgNPs and appreciated the orientation of the nanofibers. Results of tension tests revealed that modification of PCL nanofibers with pure AgNPs and eAgNPs significantly increased strength and tensile modulus. Due to the hydrophobic nature of PCL, modification with pure AgNPs and eAgNPs slightly reduced its hydrophobicity. Biodegradation tests of PCL nanofibers with eAgNPs exhibited a higher degradation rate than neat PCL nanofibers. In vitro MTT results revealed that eAgNPs doped PCL samples have better cell viability than AgNPs doped and neat PCL nanofibers. Owing to their antibacterial properties, biodegradation rates, low cytotoxicity, mechanical and surface morphologic properties of AgNPs modified PCL nanofibers containing atropa belladonna are considered to have a great potential for skin regeneration.

Bioactive anti-oxidative polycaprolactone/gelatin electrospun nanofibers containing selenium nanoparticles/vitamin E for wound dressing applications.

In this study, polycaprolactone/gelatin (PCL/GEL) electrospun nanofibers containing biogenic selenium nanoparticles (Se NPs) and Se NPs/vitamin E (VE) with average diameters of 397.8 nm and 279.5 nm, respectively (as determined by SEM inspection) were prepared and their effect on wound healing was evaluated using in-vivo studies. The energy dispersive X-ray (EDX) mapping, TEM micrograph, and FTIR spectra of the prepared nanofibers strongly demonstrated well entrapment of Se NPs and VE into scaffolds. An amount of 57% Se NPs and 43% VE were gradually released from PCL/GEL/Se NPs/VE scaffold after 4 days immersion in PBS solution (pH 7.4). The both PCL/GEL/Se NPs and PCL/GEL/Se NPs/VE scaffolds supported 3T3 cell proliferation and attachment as confirmed by MTT assay and SEM imaging. Complete re-epithelialization, low level of edema and inflammatory cells in coordination with high level of oriented collagens demonstrated the wound healing activity of PCL/GEL/Se NPs/VE. Besides, significant antioxidant efficacy of PCL/GEL/Se NPs and PCL/GEL/Se NPs/VE scaffolds was demonstrated according to GSH and MDA assays. To sum up, the prepared PCL/GEL/Se NPs/VE scaffold in the present study represented suitable healing effect on animal model which candidate it for further studies.

Honey loaded alginate/PVA nanofibrous membrane as potential bioactive wound dressing.

Honey is an ancient natural wound-healing agent and has been reintroduced to modern clinical wound care as it has various bioactivities. In this study, honey was incorporated into an alginate/PVA-based electrospun nanofibrous membrane to develop an efficient wound dressing material. The morphology and chemical composition of the nanofibrous membrane were observed by scanning electron microscopy and characterized via Fourier transform infrared spectroscopy, respectively, demonstrating that honey was successfully introduced to the nanofibers. The nanofibrous membranes with increasing honey content showed enhanced antioxidant activity, suggesting the ability to control the overproduction of reactive oxygen species. Disc diffusion assay and dynamic contact assay proved the antibacterial activity of the honey loaded nanofibers towards Gram-positive bacterium (Staphylococcus aureus) and Gram-negative bacterium (Escherichia coli). The cytotoxicity assay illustrated the non-cytotoxicity and biocompatibility of the nanofibrous membranes. Therefore, the developed honey/alginate/PVA nanofibrous membranes are promising for wound dressings.

Hyperthermia Nanofiber Platform Synergized by Sustained Release of Paclitaxel to Improve Antitumor Efficiency.

Effective cancer therapy can be achieved by designing a smart nanofiber system with the combination of chemotherapy and hyperthermia. This study demonstrates the in vivo antitumor effect of a nanofiber mesh that can deliver heat and antitumor drug in a controlled manner. The mesh is composed of biodegradable poly(ε-caprolactone) (PCL) with paclitaxel (PTX) and magnetic nanoparticles (MNPs). The PCL mesh releases PTX slowly for at least 6 weeks when tested in vitro. The prolonged therapeutic effect is observed in vivo as a continuous release of medication from the mesh over an extended period of time compared with direct injection of PTX into the tumor site. In addition, the synergistic anticancer effect is achieved upon excitation of the mesh with an alternating magnetic field because the MNPs within the nanofiber generate localized heat which causes heat-induced cell killing as well as enhanced chemotherapeutic effect of PTX. Based on these results, the smart nanofiber system may be very promising for cancer therapeutics in the future and may provide knowledge for new development of localized drug delivery.

Banana starch nanocomposite with cellulose nanofibers isolated from banana peel by enzymatic treatment: In vitro cytotoxicity assessment.

The potential use of cellulose nanofibers (CNFs) as a reinforcing agent in banana starch-based nanocomposite films was investigated. CNFs were isolated from banana peel (Musa paradisiaca) by enzymatic hydrolysis. Banana starch-based nanocomposite films were prepared with CNFs using the casting method. CNFs effect on cell viability and on nanocomposite films properties' was investigated. The cytotoxicity of CNFs was assessed on Caco-2 cell line. CNFs were not cytotoxic at 50-2000 µg/mL. However, CNFs above 2000 µg/mL significantly decreased cell viability. Topography analysis showed that the incorporation of CNFs modified the film structure. The nanocomposites exhibited a complex structure due to strong interactions between CNFs and starch matrix, promoting a remarkable improvement on mechanical and water barrier properties, opacity and UV light barrier compared to the control film. CNFs can offer a great potential as reinforcing material for starch-based nanocomposite films, producing a value-added food packaging from a waste material.

Protein/CaCO3/Chitin Nanofiber Complex Prepared from Crab Shells by Simple Mechanical Treatment and Its Effect on Plant Growth.

A protein/CaCO3/chitin nanofiber complex was prepared from crab shells by a simple mechanical treatment with a high-pressure water-jet (HPWJ) system. The preparation process did not involve chemical treatments, such as removal of protein and calcium carbonate with sodium hydroxide and hydrochloric acid, respectively. Thus, it was economically and environmentally friendly. The nanofibers obtained had uniform width and dispersed homogeneously in water. Nanofibers were characterized in morphology, transparency, and viscosity. Results indicated that the shell was mostly disintegrated into nanofibers at above five cycles of the HPWJ system. The chemical structure of the nanofiber was maintained even after extensive mechanical treatments. Subsequently, the nanofiber complex was found to improve the growth of tomatoes in a hydroponics system, suggesting the mechanical treatments efficiently released minerals into the system. The homogeneous dispersion of the nanofiber complex enabled easier application as a fertilizer compared to the crab shell flakes.

Pectin based composite nanofabrics incorporated with layered silicate and their cytotoxicity.

Pectin based composite polymer nanofabrics incorporated with rectorite (REC) were fabricated via electrospinning. Continuous and uniform nanofibers were obtained by electrospinning poly (vinyl alcohol) (PVA)-Pectin (80/20) composite solution. REC was successfully introduced to the polymer composite nanofabrics, which was confirmed by Energy-dispersive X-ray spectroscopy and Fourier transform infrared spectra. Small angel X-ray diffraction demonstrated the REC in PVA-Pectin-REC composite nanofabrics was neither of an intercalated type nor of a completely exfoliated type. And organic-inorganic composite nanofabrics with enhanced thermal stability and cell viability were obtained, which was demonstrated by thermo-gravimetric analysis and cell cytotoxic evaluation results, respectively. High content of REC (≥1%) in composite nanofabrics could obviously reduce the cytotoxicity and improve the cell viability of the composite nanofabrics.

Imparting electroactivity to polycaprolactone fibers with heparin-doped polypyrrole: Modulation of hemocompatibility and inflammatory responses.

Hemocompatibility, anti-inflammation and anti-thrombogenicity of acellular synthetic vascular grafts remains a challenge in biomaterials design. Using electrospun polycaprolactone (PCL) fibers as a template, a coating of polypyrrole (PPy) was successfully polymerized onto the fiber surface. The fibers coated with heparin-doped PPy (PPy-HEP) demonstrated better electroactivity, lower surface resistivity (9-10-fold) and better anti-coagulation response (non-observable plasma recalcification after 30min vs. recalcification at 8-9min) as compared to fibers coated with pristine PPy. Red blood cell compatibility, measured by% hemolysis, was greatly improved on PPy-HEP-coated PCL in comparison to uncoated PCL (3.9±2.1% vs. 22.1±4.1%). PPy-HEP-coated PCL fibers also exhibited higher stiffness values (6.8±0.9MPa vs. 4.2±0.8MPa) as compared to PCL fibers, but similar tensile strengths. It was also observed that the application of a low alternating current led to a 4-fold reduction of platelet activation (as quantitated by CD62p expression) for the PPy-HEP-coated fibers as compared to non-stimulated conditions. In parallel, a reduction in the leukocyte adhesion to both pristine PPy-coated and PPy-HEP-coated fibers was observable with AC stimulation. Overall, a new strategy involving the use of hemocompatible conducting polymers and electrical stimulation to control thrombogenicity and inflammatory responses for synthetic vascular graft designs was demonstrated.

Evaluation of the genotoxicity of cellulose nanofibers.

BACKGROUND: Agricultural products and by products provide the primary materials for a variety of technological applications in diverse industrial sectors. Agro-industrial wastes, such as cotton and curaua fibers, are used to prepare nanofibers for use in thermoplastic films, where they are combined with polymeric matrices, and in biomedical applications such as tissue engineering, amongst other applications. The development of products containing nanofibers offers a promising alternative for the use of agricultural products, adding value to the chains of production. However, the emergence of new nanotechnological products demands that their risks to human health and the environment be evaluated. This has resulted in the creation of the new area of nanotoxicology, which addresses the toxicological aspects of these materials. PURPOSE AND METHODS: Contributing to these developments, the present work involved a genotoxicological study of different nanofibers, employing chromosomal aberration and comet assays, as well as cytogenetic and molecular analyses, to obtain preliminary information concerning nanofiber safety. The methodology consisted of exposure of Allium cepa roots, and animal cell cultures (lymphocytes and fibroblasts), to different types of nanofibers. Negative controls, without nanofibers present in the medium, were used for comparison. RESULTS: The nanofibers induced different responses according to the cell type used. In plant cells, the most genotoxic nanofibers were those derived from green, white, and brown cotton, and curaua, while genotoxicity in animal cells was observed using nanofibers from brown cotton and curaua. An important finding was that ruby cotton nanofibers did not cause any significant DNA breaks in the cell types employed. CONCLUSION: This work demonstrates the feasibility of determining the genotoxic potential of nanofibers derived from plant cellulose to obtain information vital both for the future usage of these materials in agribusiness and for an understanding of their environmental impacts.

Controlled green tea polyphenols release from electrospun PCL/MWCNTs composite nanofibers.

Poly(ɛ-caprolactone)/multi-walled carbon nanotubes (PCL/MWCNTs) composite nanofibers with various content of green tea polyphenols (GTP) were successfully fabricated via an electrospinning technology to maintain the chemical structural stability of GTP. The non-covalent interaction between MWCNTs and GTP was measured by UV-vis spectrophotometer and FT-IR. The topographical features of the nanofibers were characterized by scanning electron microscopy (SEM). The dispersibility of MWCNTs and the distribution of GTP in nanofibers were observed by transmission electron microscopy (TEM) and laser scanning confocal microscope (LSCM), respectively. In vitro degradation was also characterized in terms of the morphological change and the mass loss of the nanofiber meshes. In vitro GTP release behavior was investigated in phosphate-buffered solution (PBS) at 37°C. Alamar blue assays were performed to estimate the cytotoxicity of the nanofibers with normal osteoblast cells and the antiproliferative effects to A549 and Hep G2 tumor cells. The results exhibited that the GTP-loaded composite nanofibers possessed a significant inhibition effect to tumor cells. Therefore, GTP, as a multifunctional drug, encapsulated into polymer composite nanofibers, must have broad application prospects in cancer therapy.