Creation of a functional graded nanobiomembrane using a new electrospinning system for drug release control and an in vitro validation of drug release behavior of the coating membrane

In-situ cellulose-framework templates mediated monodispersed silver nanoparticles via facile UV-light photocatalytic activity for anti-microbial functionalization

Cellulose is well known as a biocompatible material or natural reducing material. In this study, As an eco-friendly and facile method, we prepared monodispersed silver nanoparticles (AgNPs) in cellulose-framework through photocatalytic reaction. and we fabricated electrospun fiber scaffolds with excellent antibacterial properties and biocompatibility. UV-irradiation causes the electrical change of the cellulose-framework, thereby converting Ag ions into Ag particles. We applied a three-electrode system to confirm the phenomenon. Through STEM and EDS, it was found that the synthesized AgNPs were monodisperse in the nanofibers, and antibacterial activity was confirmed using gram-negative and gram-positive bacteria. In addition, it was suggested that the gradual release of simvastatin contained in the nanofibers and excellent mineralization would be easy to apply to bone regeneration. Therefore, the manufactured composite electrospun fiber mat can be used not only in biomedical fields but also in various applications that need to prevent the accumulation of microorganisms.

Effects of Electrospun Fibrous Membranes of PolyCaprolactone and Chitosan/Poly(Ethylene Oxide) on Mouse Acute Skin Lesions

Polycaprolactone (PCL) is a synthetic polymer with good mechanical properties that are useful to produce biomaterials of clinical application. It can be successfully combined with chitosan, which enhances the biomaterial properties through the modulation of molecular and cellular mechanisms. The objective of this study was to evaluate the effects of the use of electrospun fibrous membranes consisting of polycaprolactone (PCL) or polycaprolactone coated with chitosan and poly(ethylene oxide) (PCL+CHI/PEO) on mouse skin lesions. Sixty four Black-57 mice were divided into PCL and PCL+CHI/PEO groups. A 1 cm2 lesion was made on the animals' backs, and the membranes were sutured in place. The tissues were extracted on the 3rd, 7th, and 14th days after the lesion. The tissues were analyzed by histology with Hematoxylin and Eosin (H&E) and Sirius Red stains, morphometry, immunohistochemistry, and Western blot. On the 3rd, 6th, and 9th days after the lesion, the PCL+CHI/PEO group showed a higher wound-healing rate (WHR). On the 3 day, the PCL+CHI/PEO group showed a greater amount of inflammatory infiltrate, greater expression of proliferating cell nuclear antigen (PCNA), and smooth muscle actin (α-SMA) (p < 0.05) compared to the PCL group. On the 7th day after the lesion, the PCL+CHI/PEO group showed a greater amount of inflammatory infiltrate, expression of Tumor Necrosis Factor (TNF-α) and PCNA (p < 0.05). In addition, it showed a greater immunolabeling of Monocyte Chemoattractant Protein-1 (MCP-1) and deposition of collagen fibers compared to the PCL group. The PCL+CHI/PEO membrane modulated the increase in the inflammatory infiltrate, the expression of MCP-1, PCNA, and α-SMA in lesions of mice.

Analysis of Drug Release Behavior Utilizing the Swelling Characteristics of Cellulosic Nanofibers

It is known that the behavior of a drug released from a supporting carrier is influenced by the surrounding environment and the carrier. In this study, we investigated the drug behavior of a swellable electrospun nanofibrous membrane. Nanofibrous mats with different swelling ratios were prepared by mixing cellulose acetate (CA) and polyurethane (PU). CA has excellent biocompatibility and is capable of high water uptake, while PU has excellent mechanical properties. Paclitaxel (PTX) was the drug of choice for observing drug release behavior, which was characterized by UV-spectroscopy. FE-SEM was used to confirm the morphology of the nanofibrous mats and to measure the average fiber diameters. We observed a noticeable increase in the total volume of the nanofibrous membrane when it was immersed in water. Also, the drug release behavior increased proportionally with increasing swelling rate of the composite nanofibrous mat. Biocompatibility testing of nanofiber materials was confirmed by CCK-8 assay and cell morphology was observed. Based on these results, we propose nanofibrous mats as promising candidates in wound dressing and other drug carrier applications.

Recent advances in electrospun for drug delivery purpose

Electrospun, an advanced technology, has been successfully employed for fibre production and offers many merits in novel drug delivery systems (DDSs). In recent years, electrospun has gained significant attention and attraction of the scientists in soaring numbers. This technology is superior to other technologies in fabricating the fibres which range from micrometers to manometers scale. The selection of appropriate polymers, electrospun processes and electrospun parameters play important roles in controlling the drug release while, treating serious illness. Besides, electrospraying process has similar characteristics to the electrospun and is presented briefly here. Further, in vivo and in vitro evaluations of the electrospun nanofibers are comprehensively discussed. In addition, the electrospun nanotechnology has been exploited to design drug release systems, investigate drug's pharmacokinetics and further develop DDS. The electrospun nanofibers improve bioactivity of various types of drugs including water-insoluble, soluble, anticancer and antibacterial drugs and genetic materials. In the end, the prospects and challenges in the process of designing drug-loaded electrospun nanofibers are discussed in detail.

Optimizing through computational modeling to reduce dogboning of functionally graded coronary stent material

Coronary artery disease is the leading cause of death among the men and women. One of the most suitable treatments for this problem is balloon angioplasty with stenting. Functionally graded material (FGM) stents have shown suitable mechanical behavior in simulations. While their deformation was superior to uniform materials, the study was aimed at finding the most suitable configuration to reach the optimum performance. A combination of finite element method (FEM) and optimization algorithm have been used to fulfil this objective. To do that, three different conditions have been investigated in a Palmaz-Schatz geometry, where in the first and second ones the stent was a combination of steel and CoCr alloy (L605), and the third condition was a combination of CoCr alloy (L605) and CoCr alloy (F562). In the first and third conditions, dogboning was the objective function, but in the second condition a non-uniform deformation indicator was chosen as the objective function. In all three conditions the heterogeneous index was the control variable. The stent in the third condition showed a poor performance. While in the steel/CoCr alloy (L605) stents the heterogeneous index of 0.374 showed the lowest maximum dogboning, the heterogeneous index of 5 had more uniform deformation. Overall due to the lower dogboning of the steel/CoCr alloy (L605) stent with heterogeneous index of 0.374, this stent is recommended as the optimum stent in this geometrical configuration.

Intermolecular Interactions and the Release Pattern of Electrospun Curcumin-Polyvinyl(pyrrolidone) Fiber

An electrospun fiber of polyvinyl(pyrrolidone) (PVP)-Tween 20 (T20) with curcumin as the encapsulated drug has been developed. A study of intermolecular interactions was performed using Raman spectroscopy, Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The Raman and FT-IR studies showed that curcumin preferrably interacted with T20 and altered PVP chain packing, as supported by XRD and physical stability data. The hydroxyl stretching band in PVP shifted to a lower wavenumber with higher intenstity in the presence of curcumin and PVP, indicating that hydrogen bond formation is more intense in a curcumin or curcumin-T20 containing fiber. The thermal pattern of the fiber did not indicate phase separation. The conversion of curcumin into an amorphous state was confirmed by XRD analysis. An in vitro release study in phosphate buffer pH 6.8 showed that intermolecular interactions between each material influenced the drug release rate. However, low porosity was found to limit the hydrogen bond-mediated release.

The metamorphosis of vascular stents: passive structures to smart devices

The role of nanotechnology enabled techniques in the evolution of vascular stents.