Fabrication of an efficient vanadium redox flow battery electrode using a free-standing carbon-loaded electrospun nanofibrous composite.

Vanadium redox flow batteries (VRFBs) are considered as promising electrochemical energy storage systems due to their efficiency, flexibility and scalability to meet our needs in renewable energy applications. Unfortunately, the low electrochemical performance of the available carbon-based electrodes hinders their commercial viability. Herein, novel free-standing electrospun nanofibrous carbon-loaded composites with textile-like characteristics have been constructed and employed as efficient electrodes for VRFBs. In this work, polyacrylonitrile-based electrospun nanofibers loaded with different types of carbon black (CB) were electrospun providing a robust free-standing network. Incorporation of CBs (14% and 50% weight ratio) resulted in fibers with rough surface and increased mean diameter. It provided higher BET surface area of 83.8 m2 g-1 for as-spun and 356.7 m2 g-1 for carbonized fibers compared to the commercial carbon felt (0.6 m2 g-1). These loaded CB-fibers also had better thermal stability and showed higher electrochemical activity for VRFBs than a commercial felt electrode.

Self-assembling peptides cross-linked with genipin: resilient hydrogels and self-standing electrospun scaffolds for tissue engineering applications.

Self-assembling peptides (SAPs) are synthetic bioinspired biomaterials that can be feasibly multi-functionalized for applications in surgery, drug delivery, optics and tissue engineering (TE). Despite their promising biocompatibility and biomimetic properties, they have never been considered real competitors of polymers and/or cross-linked extracellular matrix (ECM) natural proteins. Indeed, synthetic SAP-made hydrogels usually feature modest mechanical properties, limiting their potential applications, due to the transient non-covalent interactions involved in the self-assembling phenomenon. Cross-linked SAP-hydrogels have been recently introduced to bridge this gap, but several questions remain open. New strategies leading to stiffer gels of SAPs may allow for a full exploitation of the SAP technology in TE and beyond. We have developed and characterized a genipin cross-linking strategy significantly increasing the stiffness and resiliency of FAQ(LDLK)3, a functionalized SAP already used for nervous cell cultures. We characterized different protocols of cross-linking, analyzing their dose and time-dependent efficiency, influencing stiffness, bioabsorption time and molecular arrangements. We choose the best developed protocol to electrospin into nanofibers, for the first time, self-standing, water-stable and flexible fibrous mats and micro-channels entirely made of SAPs. This work may open the door to the development and tailoring of bioprostheses entirely made of SAPs for different TE applications.

Fabrication of nanofibrous electrospun scaffolds from a heterogeneous library of co- and self-assembling peptides.

Self-assembling (SAPs) and co-assembling peptides (CAPs) are driving increasing enthusiasm as synthetic but biologically inspired biomaterials amenable of easy functionalization for regenerative medicine. On the other hand, electrospinning (ES) is a versatile technique useful for tailoring the nanostructures of various biomaterials into scaffolds resembling the extracellular matrices found in organs and tissues. The synergistic merging of these two approaches is a long-awaited advance in nanomedicine that has not been deeply documented so far. In the present work, we describe the successful ES of a library of diverse SAPs and CAPs into biomimetic nanofibrous mats. Our results suggest that suitable ES solutions are characterized by high concentrations of peptides, providing backbone physical chain entanglements, and by random coil/α-helical conformations while ß-sheet aggregation may be detrimental to spinnability. The resulting peptide fibers feature interconnected seamless mats with nanofibers average diameters ranging from ∼100nm to ∼400nm. Also, peptide chemical nature and ES set up parameters play pivotal roles in determining the conformational transitions and morphological properties of the produced nanofibers. Far from being an exhaustive description of the just-opened novel field of ES-assembled peptides, this seminal work aims at shining a light on a still missing general theory for the production of electrospun peptidic biomaterials bringing together the spatial, biochemical and biomimetic of these two techniques into unique scaffolds for tissue engineering. STATEMENT OF SIGNIFICANCE: Construction of peptide hydrogels has received considerable attention due to their potential as nanostructures amenable of easy functionalization and capable of creating microenvironments suited for culturing cells and triggering tissue regeneration. They display a superior biocompatibility unmatched by other known synthetic biomaterials so far. However, their applications are confined to body fillers because most of them do spontaneously form hydrogels, while effective tissue regeneration often requires well-defined fibrous scaffolds. In this work, we developed electrospun fibers of various peptides (cross-beta self-assembling, hierarchically assembling, functionalized, co-assembling) and we provided a deep understanding of the crucial phenomena to be taken into account when peptides fibers fabrication. These results open new venues for exploring novel regenerative applications of peptide nanofibrous scaffolds.

Recent therapeutic approaches for spinal cord injury.

A spinal cord injury (SCI) often causes permanent changes in strength and sensation functions below the site of the injury and affects thousands of people each year. Transplantation of stem cells is a promising approach in acute SCI as it may support spinal cord repair. However, in case of chronic SCI greater amounts of nervous tissue have to be regenerated, leaving scaffold transplantation the only feasible option for cellular engraftment and nervous bridging. The aim of regenerative medicine, specifically tissue engineering, is to create a microenvironment that mimics native extracellular matrix (ECM), capable of promoting specific cell-matrix interactions, coaxing cell behavior, and fostering host tissue regeneration. In this regard, nanostructured scaffolds are currently the most promising advanced substrates capable of supporting nervous fiber ingrowth and delivery of neurotrophic drugs. Among them, electrospinning technique and Self-Assembling Peptides (SAPs) have recently attracted lots of attention for their reproducible synthesis and high tailorability. This review highlights clinical trials and recent encouraging strategies for spinal cord repair comprising both cell therapy and nanomedicine.

Impacts of insulin infusion protocol on blood glucose level and outcomes in acute coronary syndrome patients with diabetes mellitus.

BACKGROUND: Acute coronary syndrome is the most common disease in the world. Several studies suggest that hyperglycemia is associated with poor clinical outcomes in patients with coronary artery disease. The aim of this study was to investigate the impact of insulin infusion protocol and conventional therapy on the blood glucose level and outcomes in acute coronary syndrome patients with diabetes mellitus. MATERIALS AND METHODS: We studied 64 patients (32 in each group) with acute coronary syndrome and acute myocardial infarction, who were admitted to the coronary care unit in a hospital in Isfahan, Iran in 2012. Inclusion criterion was blood sugar (BS) of more than 180 mg/dl on admission. Patients in the intervention group received insulin with East Jefferson insulin infusion protocol for at least 4 h, and in the control group, the subjects received subcutaneous insulin (conventional therapy) for at least for 48 h. Independent t-test, Student's t-test, and Chi-square test were used to analyze the data. RESULTS: Groups were matched for baseline characteristics. Blood glucose was significantly reduced in the two groups (P < 0.001), and the mean blood glucose level in the interaction group was significantly less than in the control group (P = 0.0002). Hypoglycemia was 31.2% and 25% in the intervention and control groups, respectively. The frequency of hypoglycemia did not differ significantly between the two groups (P = 0.75). Time to reach target insulin level differed between the two groups (4.75 h in the intervention group and 36.93 h in the control group; P < 0.001). CONCLUSIONS: Our research showed that use of insulin infusion protocol is better in maintaining glycemia control compared to subcutaneous sliding scale method. The protocol allows nurses to commence and maintain the infusion more effectively and safely compared to the traditional method.

Drug release profile in core-shell nanofibrous structures: a study on Peppas equation and artificial neural network modeling.

Release profile of drug constituent encapsulated in electrospun core-shell nanofibrous mats was modeled by Peppas equation and artificial neural network. Core-shell fibers were fabricated by co-axial electrospinning process using tetracycline hydrochloride (TCH) as the core and poly(l-lactide-co-glycolide) (PLGA) or polycaprolactone (PCL) as the shell materials. The density and hydrophilicity of the shell polymers, feed rates and concentrations of core and shell phases, the contribution of TCH in core material and electrical field were the parameters fed to the perceptron network to predict Peppas constants in order to derive release pattern. This study demonstrated the viability of the prediction tool in determining drug release profile of electrospun core-shell nanofibrous scaffolds.