4 research outputs found
CONTROLLED DRUG DELIVERY AND CELLULAR ACTIVITIES FROM ELECTROSPUN FIBERS
No full textElectrospun drug-eluting fibers have demonstrated potential applications in topical drug delivery, where modulations of drug releases were achieved through polymer fiber compositions. In this study, blend fibers of polycaprolactone (PCL) and polyethylene oxide (PEO) at various compositions were electrospun from 10 wt% of polymer solutions to encapsulate a model drug of ibuprofen (IBP). Results showed that average polymer solution viscosities determined the electrospinning parameters and the resulting average fiber diameters. In vitro release of IBP suggested a transition from a gradual release to a fast release when increasing PEO contents in the PCL/PEO blend fibers up to 120 minutes. In vitro viability of PCL/PEO blend fibers using MTT assays showed that the fibers were biocompatible with MEF-3T3 fibroblasts. To further modulate the drug release rate, fibers with a core/shell hierarchical structure were electrospun to encapsulate IBP as well as epidermal growth factor (EGF). Results suggested a gradual release of IBP up to 120 hours, dependent on core composition and shell layer thickness. In vitro viability of IBP-loaded PCL fibers showed that the fibers were biocompatible with NIH-3T3 fibroblasts. In vitro release of EGF from PCL core/shell fibers showed two stages of release profiles: an initial burst release on the first day followed by a sustained release over 21 days. Specifically, the 1C2S fibers exhibit an initial burst release, with a sharp increase in EGF release within the first few hours, followed by a slower release to achieve a complete release within 11 days. The cumulative release of EGF from the 1C4S and 1C8S fibers increased gradually over time, achieving 85% and 77 %, respectively, at 21 days. In vitro viability of EGF-loaded fibers showed biocompatibility of the fiber with NIH-3T3 fibroblasts. In addition, in vitro cell proliferation showed an increased number of cells over 7 days, while scratch assay confirmed that the release of EGF from the core-shell fibers maintained their biological cues to promote cellular activities. In conclusion, microfibers with hierarchical designs are capable of modulating IBP and EGF releases and are suitable for topical drug delivery applications
Fabrication of drug-eluting polycaprolactone and chitosan blend microfibers for topical drug delivery applications
No full textChronic and non-healing wounds show delayed and incomplete healing process, which expose the patients to a high risk of infection. These types of wounds require frequent change of dressing, which is a burden on the patients. In addition, ideal dressing needs to meet the requirements in minimizing microbial infiltration and growth while balancing moisture and exchanging oxygen with outside environment. To overcome the challenge in frequent change of dressing and meet the design requirements, current researches have focused on the development of electrospun fibers with incorporation of small molecule drugs for sustained release purpose. In this study, electrospinning was performed to fabricate blend fibers consisting of 15 wt% of polycaprolactone (PCL) and 4 wt% of chitosan (CS) at various blend ratios with the incorporation of a model small molecule drug, acetylsalicylic acid (ASA). Results showed that fibers became more hydrophilic when increasing CS concentration from 0% to 60% in PCL/CS blank fibers. Increasing CS concentration decreased fiber diameter resulting in the decrease of fiber mechanical properties. Furthermore, the addition of 10% w/w ASA also made the fibers more hydrophilic and further decreased the fiber diameter. There were no linear relationships between CS concentrations and fiber mechanical properties in the drug-loaded samples, which indicated some level of drug-polymer interactions. Fiber mechanical properties and drug release rates were two major aspects indicative of strong and/or weak drug-polymer interactions. In vitro drug release in PBS buffer solution showed a burst profile of ASA (30%) up to 2 h followed by a zero-order release rate up to 2 days
Computational Fluid Dynamics Analysis of Slip Flow and Heat Transfer at the Entrance Region of a Circular Pipe
No full textIn the era of sustainable development goals (SDGs), energy efficient heat transfer systems are a must. Convective heat transfer within circular pipes is an important field of research on a rarely addressed limitation of fluid flows. Vacuum solar tubes is one of many applications that could benefit from the existence of nanoparticles, Al2O3, for example, to enhance the heating of air or water steam. The current research investigates the impacts of the Reynolds number (Re), Prandtl number (Pr), Knudsen number (Kn), aspect ratio (x/Dh), and volume fraction of Al2O3 nanoparticles (ϕ) on the Nusselt number (Nu) under constant wall heat flux conditions. An axisymmetric computational fluid dynamics (CFD) analysis of the nanofluid flowing at the entrance region of a circular pipe was conducted under a slip flow at steady-state developing laminar conditions using the Ansys-Fluent 2018 software package. A mesh sensitivity analysis was conducted, and a proper number of mesh elements was selected. The results showed that an increasing Re and/or ϕ would result in an increasing Nu. The dependance of Nu on Kn was strong due to the high slip values and temperature jump. An increasing x/Dh ratio resulted in reduced Nu values. The major impact was due to Kn, which caused a reduction of up to 40% in the Nu value due to slip conditions. However, there was an enhancement of 2.5% in the heat transfer due to the addition of nanoparticles, which was found at Re = 250, Kn = 0.1, and ϕ = 0.1 (Pr = 0.729). Finally, Nuavg, Nux, U/Um, and ReCf were corelated with Kn, Pr, Re, and x/Dh with proper coefficient of determination (R2) values
Electrospun Ibuprofen-Loaded Blend PCL/PEO Fibers for Topical Drug Delivery Applications
No full textElectrospun drug-eluting fibers have demonstrated potentials in topical drug delivery applications, where drug releases can be modulated by polymer fiber compositions. In this study, blend fibers of polycaprolactone (PCL) and polyethylene oxide (PEO) at various compositions were electrospun from 10 wt% of polymer solutions to encapsulate a model drug of ibuprofen (IBP). The results showed that the average polymer solution viscosities determined the electrospinning parameters and the resulting average fiber diameters. Increasing PEO contents in the blend PCL/PEO fibers decreased the average elastic moduli, the average tensile strength, and the average fracture strains, where IBP exhibited a plasticizing effect in the blend PCL/PEO fibers. Increasing PEO contents in the blend PCL/PEO fibers promoted the surface wettability of the fibers. The in vitro release of IBP suggested a transition from a gradual release to a fast release when increasing PEO contents in the blend PCL/PEO fibers up to 120 min. The in vitro viability of blend PCL/PEO fibers using MTT assays showed that the fibers were compatible with MEF-3T3 fibroblasts. In conclusion, our results explained the scientific correlations between the solution properties and the physicomechanical properties of electrospun fibers. These blend PCL/PEO fibers, having the ability to modulate IBP release, are suitable for topical drug delivery applications
