The release behavior of a water-soluble small molecule drug from the drug-loaded nanofibers prepared by emulsion-electrospinning was investigated. Doxorubicin hydrochloride (Dox), a water-soluble anticancer agent, was used as the model drug. The laser scanning confocal microscopic images indicated that the drug was well incorporated into amphiphilic poly(ethylene glycol)-poly(L-lactic acid) (PEG-PLA) diblock copolymer nanofibers, forming "core-sheath" structured drug-loaded nanofibers. The drug release behavior of this drug-loaded system showed a three-stage diffusion-controlled mechanism, in which the release rate of the first stage was slower than that of the second stage, but both obeyed Fick's second law. Based on these results, it is concluded that the Dox-loaded fibers prepared by emulsion-electrospinning represent a reservoir-type delivery system in which the Dox release rate decreases with the increasing Dox content in the fibers.
"Controlled release drug therapy is a process in which a predetermined concentration of a drug is delivered to a particular target over a specified duration, in a predicted behavior . The main goal of this process is to increase the effectiveness of the drug by means of localizing the delivery, decreasing the side effects, decreasing the number of the administrations and even elimination of specialized administration methods  . Numerous studies have been carried out in order to design, characterize and develop controlled drug delivery systems; the focus has been aimed in particular towards drug delivery systems that utilize biodegradable polymers such as different grades of poly(lactic acid) [3e6]. "
[Show abstract][Hide abstract] ABSTRACT: In vitro drug release mechanism of core/shell nanofibers of poly(methyl methacrylate)(PMMA)–nylon6 fabricated through coaxial electrospinning containing different concentrations of ampicillin was investigated. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Korsmeyer–Peppas equation and Fickian diffusion model were utilized to characterize the system. Antibacterial activity of the designed drug delivery system was investigated against Gram-positive Listeria innocua through optical density (OD) measurement. The system showed sustained drug release through three stages; although the release in stage I followed non-Fickian diffusion, Fickian diffusion was proven to be the release mechanism of stages II and III. A significant decrease in the diffusion coefficient from stage II to stage III was observed, which is believed to be the consequence of crystallization of fibers as a result of long-term incubation in an aqueous solution. Finally, the antibacterial activity of the system was verified by means of optical density (OD) measurements against Gram-positive L. innocua.
"Electrospinning is a versatile polymer processing technique to fabricate engineered scaffolds with micro to nanoscale topography and high porosity mimic to the natural extracellular matrix (ECM)  . It offers great flexibility in terms of material selection for drug delivery applications, and a rich variety of drugs have been physically or chemically formulated within electrospun nanofibers or on their surfaces, such as antibiotics     , anticancer drugs  , proteins  , and DNA   . Meanwhile, the drug release mechanism is associated with polymer degradation and diffusion pathway, and the release profile of drug from electrospun nanofibers may be tuned by the polymer composition and fiber morphology . "
[Show abstract][Hide abstract] ABSTRACT: Fabrication of nanofiber-based drug delivery system with controlled release property is of general interest in biomedical sciences. In this study, we prepared an antibiotic drug tetracycline hydrochloride (TCH)-loaded halloysite nanotubes/poly(lactic-co-glycolic acid) composite nanofibers (TCH/HNTs/PLGA), and evaluated the drug release and antibacterial activity of this drug delivery system. The structure, morphology, and mechanical properties of the formed electrospun TCH/HNTs/PLGA composite nanofibrous mats were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and tensile testing. We show that the incorporation of TCH-loaded HNTs within the PLGA nanofibers is able to improve the tensile strength and maintain the three-dimensional structure of the nanofibrous mats. In vitro viability assay and SEM morphology observation of mouse fibroblast cells cultured onto the fibrous scaffolds demonstrate that the developed TCH/HNTs/PLGA composite nanofibers are cytocompatible. More importantly, the TCH/HNTs/PLGA composite nanofibers are able to release the antibacterial drug TCH in a sustained manner for 42 days and display antimicrobial activity solely associated with the encapsulated TCH drug. With the improved mechanical durability, sustained drug release profile, good cytocompatibility, and non-compromised therapeutic efficacy, the developed composite electrospun nanofibrous drug delivery system may be used as therapeutic scaffold materials for tissue engineering and drug delivery applications.
"It has attracted considerable attention recently in many applications , such as drug and protein carriers in controlled release  , scaffolds in tissue engineering  , filtration   , biosensors   and food manufacturing . Electrospinning could therefore become a simple yet powerful means of preparing desirable fibrous membrane if it could be performed in a reliable and predictable way. "
[Show abstract][Hide abstract] ABSTRACT: Four types of laccase-carrying electrospun fibrous membranes (LCEFMs), with high laccase-catalytic activity and sorption capacity, were fabricated by emulsion electrospinning. These LCEFMs were composed of beads-in-string structural fibers, with nanoscale pores distributed on the surface and active laccase encapsulated inside. This obtained structure could protect laccase from external disturbance, resulting in that all of the four LCEFMs retained more than 70% of activity relative to free laccase, and after glutaraldehyde treatment, their storage and operational stabilities were definitely improved. The retained activities and stabilities of the LCEFMs were closely related to the hydrophilic–hydrophobic property of the polymer. Moreover, these LCEFMs possessed high adsorptivity for polycyclic aromatic hydrocarbons (PAHs), and the sorption capacities and rates were mainly influenced by the specific surface area of the LCEFMs and the hydrophilic–hydrophobic property of the polymer. The sorption of PAHs on the LCEFMs could significantly enhance their degradation efficiencies by laccase, which was obviously higher than those by free laccase. A mechanism of PAH degradation promoted by sorption was proposed.
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