Payam Zahedi

Morphology, drug release, antibacterial, cell proliferation, and histology studies of chamomile-loaded wound dressing mats based on electrospun nanofibrous poly(ɛ-caprolactone)/polystyrene blends

For the first time, it has been tried to achieve optimum conditions for electrospun poly(ε-caprolactone)/polystyrene (PCL/PS) nanofibrous samples as active wound dressings containing chamomile via D-optimal design approach. In this work, systematic in vitro and in vivo studies were carried out by drug release rate, antibacterial and antifungal evaluations, cell culture, and rat wound model along with histology observation. The optimized samples were prepared under the following electrospinning conditions: PCL/PS ratio (65/35), PCL concentration 9%(w/v), PS concentration 14%(w/v), distance between the syringe needle tip and the collector 15.5 cm, applied voltage 18 kV, and solution flow rate 0.46 mL h(-1) . The FE-SEM micrographs showed electrospun PCL/PS (65/35) nanofibrous sample containing 15% chamomile had a minimum average diameter (∼175 nm) compared to the neat samples (∼268 nm). The drug released resulted in a gradual and high amount of chamomile from the optimized PCL/PS nanofibrous sample (∼70%) in respect to PCL and PS nanofibers after 48 h. This claim was also confirmed by antibacterial and antifungal evaluations in which an inhibitory zone with a diameter of about 7.6 mm was formed. The rat wound model results also indicated that the samples loaded with 15% chamomile extract were remarkably capable to heal the wounds up to 99 ± 0.5% after 14 days post-treatment periods. The adhesion of mesenchymal stem cells and their viability on the optimized samples were confirmed by MTT analysis. Also, the electrospun nanofibrous mats based on PCL/PS (65/35) showed a high efficiency in the wound closure and healing process compared to the reference sample, PCL/PS nanofibers without chamomile. Finally, the histology analysis revealed that the formation of epithelial tissues, the lack of necrosis and collagen fibers accumulation in the dermis tissues for the above optimized samples.

Preparation and release properties of electrospun poly(vinyl alcohol)/poly(ɛ-caprolactone) hybrid nanofibers: Optimization of process parameters via D-optimal design method

AbstractThe main purpose of this work was to develop biomedical electrospun nanofibrous mats based on a poly(vinyl alcohol)/poly(ɛ-caprolactone) (80/20) hybrid with a defined drug release rate using tetracycline hydrochloride as a model drug. The electrospinning process parameters, such as polymer solution concentration, distance between injecting syringe tip/collector, voltage, injected flow rate and the polyvinyl alcohol cross-linking time were optimized via a D-optimal design method for a suitable nanofiber diameter with an optimal drug release rate. The morphology of nanofibers and their mean diameters were studied by a scanning electron microscopy technique. The results showed that the mean diameters of nanofibers were significantly reduced after drug loading. The swelling, weight loss and biodegradability of nanofibers samples investigated by FTIR were also determined. Two main mechanisms via penetration and erosion were evaluated. In vitro drug release in a phosphate buffer environment at pH=7.2 for the samples demonstrated that the polymer type and hydrophilic nature of the polymer/drug system is very effective in the kinetics and mechanism of drug release. Hybridization of poly(vinyl alcohol)/poly(ɛ-caprolactone) with a known ratio showed to be a suitable and useful method in the electrospinning of nanofibers samples for superior control of the drug release rate. Finally, nanofibrous mats of polyvinyl alcohol and polyvinyl alcohol/poly(ɛ-caprolactone) hybrid (80/20) had much better drug release rate characteristics for tetracycline hydrochloride as a model drug compared with cast film samples loaded with the same drug.

Fabrication and characterization of electrospun laminin‐functionalized silk fibroin/poly(ethylene oxide) nanofibrous scaffolds for peripheral nerve regeneration

The peripheral nerve regeneration is still one of the major clinical problems, which has received a great deal of attention. In this study, the electrospun silk fibroin (SF)/poly(ethylene oxide) (PEO) nanofibrous scaffolds were fabricated and functionalized their surfaces with laminin (LN) without chemical linkers for potential use in the peripheral nerve tissue engineering. The morphology, surface chemistry, thermal behavior and wettability of the scaffolds were examined to evaluate their performance by means of scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and water contact angle (WCA) measurements, respectively. The proliferation and viability of Schwann cells onto the surfaces of SF/PEO nanofibrous scaffolds were investigated using SEM and thiazolyl blue (MTT) assay. The results showed an improvement of SF conformation and surface hydrophilicity of SF/PEO nanofibers after methanol and O2 plasma treatments. The immunostaining observation indicated a continuous coating of LN on the scaffolds. Improving the surface hydrophilicity and LN functionalization significantly increased the cell proliferation and this was more prominent after 5 days of culture time. In conclusion, the obtained results revealed that the electrospun LN-functionalized SF/PEO nanofibrous scaffold could be a promising candidate for peripheral nerve tissue regeneration.

Electrospun egg albumin-PVA nanofibers containing tetracycline hydrochloride: Morphological, drug release, antibacterial, thermal and mechanical properties

In this study, electrospun egg albumin-poly(vinyl alcohol) (PVA/EA) nanofibrous samples containing tetracycline hydrochloride (TC-HCl) were prepared. The performance of EA loaded PVA nanofibers for controlled release of TC-HCl was investigated by SEM, ATR-FTIR and UV-vis spectrophotometry. Afterwards, the antibacterial, thermal and mechanical properties were carried out for these samples. The obtained results from SEM micrograph images showed that the simultaneous use of EA protein and TC-HCl antibiotic in the electrospun PVA samples led to a uniform and smooth fibers with an average diameter of about 590 nm. The ATR-FTIR spectrum proved the effect of EA on the PVA molecular chains by representing characteristic peaks located at 700–850 cm−1 and 3285 cm−1 wavenumbers corresponding to -NH2 and -NH-groups, respectively. The UV-vis results indicated a gradual and controlled TC-HCl release from the PVA/EA nanofibrous samples. Also, the difference between antibacterial inhibition zones around the samples confirmed the drug release results. Furthermore, the DSC thermograms exhibited the amorphous status of TC-HCl did not change while incorporated into the PVA nanofibrous samples. Finally, the mechanical properties of the samples demonstrated the key role of EA as a brittleness agent in PVA fibers.

Microfluidic-aided fabrication of nanoparticles blend based on chitosan for a transdermal multidrug delivery application

The aim of this work was to provide a microfluidic-aided fabrication of nanoparticles based on chitosan/poly(N-isopropylacrylamide-co-acrylic acid)/cellulose laurate [CS/P(NIPAAm-co-AAc/CL] blend for transdermal multidrug delivery applications. The scanning electron microscopy (SEM) and dynamic light scattering (DLS) results showed that the diameter sizes of samples were in the range from 200 to 300nm along with a narrow size distribution. Also, the CS-based nanoparticles containing tretinoin and clindamycin phosphate prepared using microfluidic technique exhibited a sustained control release of the drugs as well as minimum inhibitory and bactericidal concentrations compared to the samples fabricated via bulk mixing method. The thermal stability of the drugs loaded nanoparticles revealed a reduction in degradation for those fabricated by using microfluidic technique at 45°C for one month. Afterward, the in vivo assessments confirmed that by applying the microfluidically generated nanoparticles containing two drugs, a declined superficial reddening (erythema) and suitable transdermal permeation as well as residency were happened with respect to the those samples prepared via bulk mixing method and also the drugs solution alone. Finally, these CS-based nanoparticles showed sufficient potential used for transdermal multidrug delivery applications.

Electrospun poly (N-isopropylacrylamide-co-acrylic acid)/cellulose laurate blend nanofibers containing adapalene: Morphology, drug release, and cell culture studies

ABSTRACT In this work, a thermo- and pH-sensitive polymer based on poly (N-isopropylacrylamide-co-acrylic acid)/cellulose laurate blend [P(NIPAAm-co-AAc)/CL] was electrospun to produce nanofibers containing adapalene. The synthesized P(NIPAAm-co-AAc), and CL were characterized by ATR-FTIR and 1H NMR spectroscopies. The thermal behavior of the electrospun nanofibrous samples were determined by a DSC. Afterward, the drug release in different temperatures and pHs from the nanofibers was investigated by UV-vis spectrophotometry and then the LCST behavior of the samples containing adapalene was observed by an ESEM. Moreover, the fibroblast cells culture was carried out with and without adapalene and the cell cytotoxicity of the samples was evaluated via MTT assay. The results from (H&E) and DAPI staining of the viable cells onto the samples surfaces revealed the adapalene has a remarkable short-term potential for the fibroblast cells mortality. It was found that the adapalene loaded electrospun nanofibrous samples enabled to minimize the adverse side effects of the drug by controlling release during three days of cell culture. GRAPHICAL ABSTRACT

Morphological, thermal and drug release studies of poly (methacrylic acid)-based molecularly imprinted polymer nanoparticles immobilized in electrospun poly (ε-caprolactone) nanofibers as dexamethasone delivery system

Electrospun poly (ε-caprolactone) (PCL) nanofibers containing molecularly imprinted polymer (MIP) nanoparticles based on methacrylic acid (MAA) were prepared for controlled release of dexamethasone (Dexa). First, the MIPs consisting of Dexa were synthesized via precipitation polymerization. Their recognition sites formation and thermal properties were investigated by FTIR and TGA tests, respectively. The results showed that by selecting a monomer: template (MAA:Dexa) molar ratio of 6 : 1, MIP nanoparticles were produced with imprinting factor of 1.80. The FESEM and TEM images showed the MIPs average diameter of 394±9.7 nm and appropriate immobilization of them in PCL nanofibers, respectively. Moreover, the cumulative release of Dexa from the MIP-loaded nanofibrous samples was studied by UV-vis spectrophotometry and revealed a suitable controlled release of the drug during four days. Afterward, Dexa release followed Higuchi model which indicated the main mechanism was governed by Fickian diffusion theory.

Comparison between mechanical properties of aged and unaged silicone rubbers filled with titanium dioxide, quartz, aluminium silicate and vulkasil (s type)

Abstract Silicone rubbers have advantageous thermal and electrical properties compared with other elastomers. Their mechanical properties, such as tensile strength and tear resistance are relatively weak compared with other elastomers. In this work, inorganic fillers such as titanium dioxide (TiO2) 2 and 5 phr, quartz, aluminium silicate and vulkasil (s type) 5, 15 and 25 phr were used in silicone rubber compound samples. Improvement in mechanical and processing properties are observed for these samples. The samples containing 2 phr TiO2 had a better tensile strength and transparency compared with those containing 5 phr TiO2. Determination of tensile strength, elongation at break, modulus, tear resistance, resilience and compression set of aged and unaged samples showed that higher values are obtained for samples containing quartz.

Fabrication of random and aligned-oriented cellulose acetate nanofibers containing betamethasone sodium phosphate: structural and cell biocompatibility evaluations

Abstract: The objective of this work was to prepare electrospun cellulose acetate (CA) nanofibers containing betamethasone sodium phosphate (BSP). Two different morphologies including random and aligned orientations were rationally designed to improve the performance of samples in in vitro experiments. By comparing the CA nanofibrous samples with randomly and aligned-oriented morphologies, the scanning electron microscopy images showed that the neat aligned-oriented nanofibers with an average diameter of 180±15 nm could be obtained using a high-speed rotating collector. Subsequently, the tensile test confirmed that the aligned CA nanofibers had higher mechanical properties than that of the randomly oriented ones. Moreover, the BSP release profile obtained by UV-vis spectrophotometry depicted that the aligned samples had an initial burst release of BSP followed by a slow penetration of the drug with a gentle slope during 72 h. Furthermore, the ultimate amounts of BSP released from the random and aligned CA nanofibers into the phosphate buffer solution were 63% and 53%, respectively. Finally, human adipose-derived mesenchymal stem cells were seeded on both aligned and random electrospun CA nanofibrous samples containing BSP. The thiazolyl blue and hematoxylin and eosin staining results showed that the BSP-loaded nanofibers with the aligned morphology provided the most suitable environment for the cells’ growth, viability, and proliferation.

Optimization of electrospinning parameters for producing silk fibroin/poly(ethylene oxide) nanofibers using D-optimal method

ABSTRACT Despite the ease of the electrospinning process of synthetic polymers, the adjustment of several independent variables for natural ones is a complex procedure. In this work, the electrospinning parameters of silk fibroin (SF)/poly(ethylene oxide) (PEO) blends including tip-to-collector distance (X1), applied voltage (X2), flow rate (X3) and SF/PEO ratio (X4) were optimized using the D-optimal method. By considering the response surface plots and interaction graphs as well as observing the scanning electron microscopy (SEM) images, the optimized conditions were set as follows: X1 = 15 cm, X2 = 12 kV, X3 = 1.2 mL/h and X4 = 4. Accordingly, the electrospun SF/PEO nanofibrous sample with uniform morphology and an average diameter of 182 ± 55 nm was obtained.