Electrospun Fiber Mats with Metronidazole: Design, Evaluation, and Release Kinetics

Novel drug delivery systems (DDSs) strive to eliminate or at least reduce the side effects and limitations associated with conventional medical products. Among the many potential candidates for DDSs, there are one-dimensional micro- and nanostructured materials such as electrospun fibers. In this study, two different polymers, i.e., amphiphilic block copolymer (poly(2-vinylpyridine-co-styrene)) and hydrophobic polymer (polycaprolactone), were utilized as base materials for fibers. Through the electrospinning and coaxial electrospinning techniques, fibers with diverse architectures were obtained, homogeneous or core/shell structures. An antibacterial drug (metronidazole) in varying concentrations was incorporated into the electrospun fibers. The potential application of the obtained electrospun fiber mats is as a dressing for wounds or the treatment of periodontitis. The average diameter of fibers fell within the range of 700-1300 nm, with a drug content of 7-27 wt %. The amorphization or decrease in crystallinity of metronidazole present in the fibers was achieved during the electrospinning process. In vitro drug release tests showed that burst effects can be successfully suppressed, and more sustained release can be accomplished for some formulations. Therefore, electrospun polymer fiber mats are promising candidates for the local delivery of active substances.

Synergistic inducement of programmed cell death in breast cancer cell line and microbial growth inhibition by methylcellulose blended polymeric nanofiber mats through controlled drug release

Cancer patients require a drug carrier for controlled release of anticancer drug alongside with the properties of eradicating microbial strains that causes severe side effects during treatments. Herein, the study reports the fabrication of electrospun nanofiber mats comprised of methylcellulose blended with 5-fluorouracil drug, polyethylene glycol and polylactic acid ingrained with silica nanoparticles for the eradication of cancer cells and pathogenic microbes via controlled drug release. The fabricated nanofiber mats were thoroughly characterized by various analytical techniques. The spherical shape and size of the nanoparticle were examined by scanning and transmission electron microscopies, and structural interactions by infra-red spectral and X-ray diffraction studies. The ionic interaction among nanoparticles, drug and macromolecules were found to be responsible for higher swelling capacity (346 %) and controlled drug release (>90 %) was observed at the end of 16th day. Zero order, Higuchi and Korsmeyer-Peppas kinetics confirmed the controlled release of drug from the mats via diffusion. The cytotoxicity study against MDA-MB-231 cancer cell line resulted 65 % and 75 % of cell death in a period of 24 h, respectively and further validated by apoptosis assay using Acridine Orange and Propidium Iodide staining method. The microscopic images revealed that more apoptotic cells appeared when cancer cells are exposed with methylcellulose and polyethylene glycol incorporated nanofiber mats. Furthermore, an excellent activity was observed in growth inhibition study against bacterial and fungal strains. Hence, the fabricated nanofiber mats were proposed as proficient implants for controlled drug release in cancer therapy.

Fabrication of Thymol-loaded Isabgol/Konjac Glucomannan-based Microporous Scaffolds with Enriched Antioxidant and Antibacterial Properties for Skin Tissue Engineering Applications

An antioxidant, antibacterial, and biocompatible biomaterial is essential to repair skin wounds effectively. Here, we have employed two natural biopolymers, isabgol (ISAB) and konjac glucomannan (KGM), to prepare microporous scaffolds by freezing and lyophilization. The scaffolds are loaded with thymol (THY) to impart potent antioxidant and antibacterial activities. The physicochemical properties of the ISAB+KGM+THY scaffold, like porosity (41.8±2.4 %), swelling, and biodegradation, were optimal for tissue regeneration application. Compared to the control, ISAB+KGM+THY scaffolds promote attachment, migration, and proliferation of L929 fibroblasts. The antioxidant activity of the ISAB+KGM+THY scaffold was significantly improved after loading THY. This would protect the tissues from oxidative damage. The antibacterial activity of the ISAB+KGM+THY scaffold was significantly higher than that of the control, which would help prevent bacterial infection. The vascularization ability of the ISAB+KGM scaffold was not altered by incorporating THY in the ISAB+KGM scaffold. Therefore, a strong antioxidant, antibacterial, and biocompatible nature of the ISAB+KGM+THY scaffold could be useful for various biomedical applications.

Preparation and Properties of Electrospun PLLA/PTMC Scaffolds

Poly(L-lactide) (PLLA) and PLLA/poly(trimethylene carbonate) (PTMC) scaffolds characterised by different PLLA:PTMC mass ratios (10:0, 9:1, 8:2, 7:3, 6:4 and 5:5) were prepared via electrospinning. The results showed that increasing the PTMC content in the spinning solution caused the following effects: (1) the diameter of the prepared PLLA/PTMC electrospun fibres gradually increased from 188.12 ± 48.87 nm (10:0) to 584.01 ± 60.68 nm (5:5), (2) electrospun fibres with uniform diameters and no beads could be prepared at the PTMC contents of >30%, (3) the elastic modulus of the fibre initially increased and then decreased, reaching a maximum value of 74.49 ± 8.22 Mpa (5:5) and (4) the elongation at the breaking point of the fibres increased gradually from 24.71% to 344.85%. Compared with the PLLA electrospun fibrous membrane, the prepared PLLA/PTMC electrospun fibrous membrane exhibited considerably improved mechanical properties while maintaining good histocompatibility.

Interfacial Compatibilization into PLA/Mg Composites for Improved In Vitro Bioactivity and Stem Cell Adhesion

The present work highlights the crucial role of the interfacial compatibilization on the design of polylactic acid (PLA)/Magnesium (Mg) composites for bone regeneration applications. In this regard, an amphiphilic poly(ethylene oxide-b-L,L-lactide) diblock copolymer with predefined composition was synthesised and used as a new interface to provide physical interactions between the metallic filler and the biopolymer matrix. This strategy allowed (i) overcoming the PLA/Mg interfacial adhesion weakness and (ii) modulating the composite hydrophilicity, bioactivity and biological behaviour. First, a full study of the influence of the copolymer incorporation on the morphological, wettability, thermal, thermo-mechanical and mechanical properties of PLA/Mg was investigated. Subsequently, the bioactivity was assessed during an in vitro degradation in simulated body fluid (SBF). Finally, biological studies with stem cells were carried out. The results showed an increase of the interfacial adhesion by the formation of a new interphase between the hydrophobic PLA matrix and the hydrophilic Mg filler. This interface stabilization was confirmed by a decrease in the damping factor (tanδ) following the copolymer addition. The latter also proves the beneficial effect of the composite hydrophilicity by selective surface localization of the hydrophilic PEO leading to a significant increase in the protein adsorption. Furthermore, hydroxyapatite was formed in bulk after 8 weeks of immersion in the SBF, suggesting that the bioactivity will be noticeably improved by the addition of the diblock copolymer. This ceramic could react as a natural bonding junction between the designed implant and the fractured bone during osteoregeneration. On the other hand, a slight decrease of the composite mechanical performances was noted.

A glimpse of biodegradable polymers and their biomedical applications

Over the past two decades, biodegradable polymers (BPs) have been widely used in biomedical applications such as drug carrier, gene delivery, tissue engineering, diagnosis, medical devices, and antibacterial/antifouling biomaterials. This can be attributed to numerous factors such as chemical, mechanical and physiochemical properties of BPs, their improved processibility, functionality and sensitivity towards stimuli. The present review intended to highlight main results of research on advances and improvements in terms of synthesis, physical properties, stimuli response, and/or applicability of biodegradable plastics (BPs) during last two decades, and its biomedical applications. Recent literature relevant to this study has been cited and their developing trends and challenges of BPs have also been discussed.

Pamidronate-encapsulated electrospun polycaprolactone as a potential bone regenerative scaffold

This study explores the potential of electrospun polycaprolactone scaffolds for the controlled delivery of pamidronate disodium pentahydrate, an amino-bisphosphonate drug used for the treatment of osteoporosis. Major drawbacks associated with oral bisphosphonate therapy are its poor bioavailability and gastrointestinal side-effects. Herein, we used polycaprolactone, a well-known Food and Drug Administration–approved biomaterial, as the delivering vehicle for pamidronate disodium pentahydrate. Scaffolds based on polycaprolactone with three different formulations (1, 3, and 5 wt%) of pamidronate disodium pentahydrate were fabricated by electrospinning, and a comparative study was carried out to evaluate the effect of pamidronate disodium pentahydrate on physico-mechanical and biological properties of polycaprolactone. The observations from Fourier-transform infrared spectra and thermogravimetric analysis confirmed the successful incorporation of pamidronate disodium pentahydrate into polycaprolactone scaffolds. The study also revealed that pamidronate disodium pentahydrate–loaded scaffolds exhibited improved hydrophilicity as well as superior mechanical properties as depicted by the contact angle measurements and mechanical property evaluation. In vitro drug release studies of pamidronate disodium pentahydrate–loaded scaffolds in phosphate buffer saline at 37°C showed that all the scaffolds exhibited controlled release of pamidronate disodium pentahydrate. In vitro degradation studies further revealed that pamidronate disodium pentahydrate incorporated polycaprolactone scaffolds degraded faster as depicted by the fiber rupture and drop in mechanical properties. In vitro cell culture studies using human osteosarcoma cell lines demonstrated that pamidronate disodium pentahydrate–loaded polycaprolactone scaffolds were cytocompatible. The human osteosarcoma cells had favorable interaction with the scaffolds, and the viability of adhered cells was depicted by the fluorescein diacetate/propidium iodide staining. MTT assay further revealed enhanced cell viability on PCL/PDS3 scaffolds. Our findings bespeak that the pamidronate disodium pentahydrate–encapsulated electrospun polycaprolactone scaffolds have the potential to serve as a promising drug delivery vehicle for osteoporotic bone defect repair.

Drug-Loaded Halloysite Nanotube-Reinforced Electrospun Alginate-Based Nanofibrous Scaffolds with Sustained Antimicrobial Protection

Halloysite nanotube (HNT)-reinforced alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning to mimic the natural extracellular matrix (ECM) structure which is beneficial for tissue regeneration. An antiseptic drug, cephalexin (CEF)-loaded HNT, was incorporated into the alginate-based matrix to obtain sustained antimicrobial protection and robust mechanical properties, the key criteria for tissue engineering applications. Electron microscopic imaging and drug release studies revealed that CEF had penetrated into the lumen space of the HNT and also deposited on the outer walls, with a total loading capacity of 30 wt %. Moreover, the diameter of alginate-based nanofibers of the scaffolds ranged from 40 to 522 nm with well-aligned HNTs, resulting in superior mechanical properties. For instance, the addition of 5% (w/w) HNT improved the tensile strength (σ) and elastic modulus by 3-fold and 2-fold, respectively, compared to those of the alginate-based scaffolds without HNT. The fabricated scaffolds exhibited remarkable antimicrobial properties against both Gram-negative and Gram-positive bacteria, and the cytotoxicity studies confirmed the nontoxicity of the fabricated scaffolds. Drug release kinetics showed that CEF inside HNTs diffuses within 24 h and that the diffusion of the drug is delayed by 7 days once the CEF-loaded HNTs are incorporated into the alginate-based nanofibers. These fabricated alginate-based electrospun scaffolds with enhanced mechanical properties and sustained antimicrobial protection hold great potential to be used as artificial ECM scaffolds for tissue engineering applications.

Metal oxide nanoparticle-functionalized sebacic acid-grafted PHEAM nanocarriers for enriched activity of metronidazole against food borne bacteria: in vitro and in vivo study

Food borne infection is a serious complication caused by Listeria monocytogenes (L. monocytogenes), a dangerous bacteria.