سال:1398 | دوره: | شماره: |تعداد مقالات:6

Poly(Ɛ-caprolactone) (PCL) is a biocompatible polymer with a high potential to be used in tissue engineering especially in tight tissues. In the current study, cold atmospheric plasma (CAP) is used as a promising method for immobilization of gelatin as a functional biomacromolecule on PCL nanofibrous substrates. The CAP surface modification leads to oxidation of chemical groups existing on the PCL surface without doing any damage to the bulk properties of biomaterials for gelatin biomacromolecule grafting. The water contact angle (WCA) of the CAP-treated surface and gelatin-grafted PCL using CAP indicates an effective increment in the hydrophilicity of the PCL surface. Also to achieve the highest levels of gelatin grafting on the PCL surface, two different grafting methods and gelatin concentration diversity are utilized in the grafting process. The immobilization of gelatin biomacromolecules onto the CAP surface-modified PCL nanofibers is investigated using scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The gelatin-modified PCL substrates revealed uniform nanofibrous morphology with increased average fiber diameter. The results of FTIR spectra, including hydroxyl groups, NH groups, and amide II of gelatin-grafting peaks, confirm the gelatin immobilization on the surface of nanofibers. The metabolic activity of cultured mesenchymal stem cells (MSCs) on the surface-modified scaffolds is evaluated using MTT analysis (P ≤ 0. 05). The results of metabolic activity and also SEM and DAPI staining observations indicate proper attachment on the surface and viability for MSCs on the surface-immobilized nanofibrous scaffolds. Therefore, CAP treatment would be an effective method for biomacromolecule immobilization on nanofibers towards the enhancement of cell behavior.

This research study concerns the evaluations of nano-biocomposite ceramics’ characteristics and biocompatibility. A nanocomposite with 45S5 bioactive glass base has been synthesized by sol– gel method. The synthesized nanocomposites were characterized with the help of different techniques, using field-emission scanning electron microscope, X-ray powder diffraction, energy-dispersive X-ray spectroscopy to evaluate the crystal structure, microstructure, and the morphology of the nanocomposite. The results indicated that the synthesis of 45S5 bioactive glass– fluorapatite nanocomposites produced an average particle size of about 20– 30 nm and percentages of crystallinity of about 70– 90%. fluorapatite– 45S5 bioactive glass nanocomposites were characterized in terms of their degradation by determining the weight change percentages, pH changes, the ion release and in terms of bioactivity by checking the apatite layer formation using a solution of simulated body fluid (SBF). The results showed non-cytotoxicity and the formation of a thick apatite layer on the synthesized nanocomposites within 28 days after soaking in SBF. This is an indication of desirable bioactivity in the synthesized particles.

The drug-in-adhesive (DIA)-type matrix patches of lamotrigine are developed using variable permeation enhancers (oleic acid, PG, lemon oil and aloe vera), and drug in vitro release and its permeation are evaluated. Lamotrigine has been long used as an anti-epileptic, mood stabilizer, to treat bipolar disorder in adults and off label as an antidepressant. lamotrigine matrix patches comprising of Eudragit ® RS100 (rate-controlling polymer) and DuroTak ® 387-2510 (adhesive) were prepared by pouring the solution on backing membrane (3M-9720). The thickness of 120 μ m was adjusted through micrometer film applicator. USP Apparatus V was used for the evaluation of release profile, which was fitted into various mathematical models. Quality characteristics of patches were determined through weight variation, moisture content, moisture uptake and drug content evaluation. FTIR studies were performed for drug-excipient compatibility; Franz diffusion cell was employed for studying in vitro permeation parameters such as flux, lag time, and ER. Skin sensitivity study of optimized patch was also performed. The release from patches comprising of PG and oleic acid was maximum, i. e., 96. 24 ± 1. 15% and 91. 12 ± 1. 11%, respectively. Formulations (A1– A5) exhibited Makoid– Banakar release profile. Formulation A3 consisting of oleic acid was optimized due to enhanced permeation of drug across skin compared to other enhancers with enhancement ratio of 3. 55. Skin sensitivity study revealed patch as safe and non-allergenic. The study demonstrates that oleic acid can be used as a suitable permeation enhancer for transdermal delivery of lamotrigine from matrix-type patches.

Three types of oral administrated micronized zeolites [ZSM-5, zeolite A and Faujasite NaX (ZSM-5, ZA and ZX, respectively)] were prepared as anticancer 5-fluorouracil (5-Fu) delivery systems for colon cancer treatment. They were prepared by economically widespread and cheap natural resource, kaolin, at low temperatures, using microwave advanced tool. The obtained powders were characterized by XRD, SEM/EDX and BET; meanwhile, their degradation was investigated in two gastric fluids; FaSSGF (pH 1. 6) and FeSSGF (pH 5), through concentration measurement of their solution disintegrated elemental constituents of Na+, Al3+ and Si4+ ions. Also, the processes of drug release and mechanism in both solutions were investigated. Moreover, the inhibition action of 5-Fu-free and 5-Fu-conjugated zeolites on colon cancer cells (CaCo-2) was estimated. The results showed that, the prepared zeolites possessed high surface areas of 526, 250, and 578 m2/g for ZSM-5, ZA and ZX, respectively. Although, zeolite structures seemed significantly stable, their frameworks seemed more likely reactive with time. The ions and drug release for zeolites occurred in successively two stages and found to be pH dependent, where the drug and zeolite ions were significantly of higher values in the more acidic media of the gastric solution (pH 1. 6) than those of the mild acidic one (pH 5). The obtained activity indicated no cytotoxic affinity for all the prepared zeolite types. Accordingly, the synthesized zeolite frameworks are proposed to be of strong potential drug delivery vehicle for the treatment of gastrointestinal cancer.

A bioactive calcium sulfate/glass composite was prepared using a sintering technique, and Ca– P– Si glass particles were prepared by spray pyrolysis. The glass exhibited bioactivity in terms of its ability to form apatite in a simulated body fluid. The glass was transformed into two crystallized phases, i. e., calcium phosphate and calcium silicate, respectively, during the heating stage. The presence of the crystallized phases retarded the densification of calcium sulfate. A high sintering temperature of 1200 ° C was needed to prepare the composite. The increased addition of glass enhanced the strength and decreases the degradation rate of calcium sulfate. The new composite is not only degradable but also bioactive.

A calcium– phosphate system was obtained by sol– gel method from 0. 4 M solutions based on ethyl alcohol, tetraethoxysilane, phosphoric acid, calcium nitrate, and magnesium nitrate, sodium chloride. Compositions with different contents of CaO, Na2O, and MgO were prepared. After maturation of the solutions, heat treatments were applied at 60 ° C for 30 min; and followed by 600 ° C and 800 ° C for 1 h. Solution with 20 wt% MgO was found suitable for film production. The physicochemical processes of the formation of materials were studied, including the main stages: removal of physically bound and chemically bound water, combustion of alcohol and the products of thermo-oxidative destruction of ethoxy groups, and crystallization processes. The phase composition and structure of the films obtained were established at 600 ° C and above when crystalline forms of SiO2, CaSiO3, Ca2P2O7, and complex phosphates were fixed. In the system with the addition of magnesium ions, β-cristobalite SiO2 and stenfieldt Mg3Ca3( PO4)4 were detected; however, a crystalline sample could only be obtained at 800 ° C. In the system with sodium ions, chemical compounds Ca5( PO4)3Cl, NaCl, and SiO2 were determined. A uniform film coating was formed on the surface of the substrate. The introduction of sodium oxide into the SiO2– P2O5– CaO system increased the bioactivity of the materials obtained.