An alginate-poly(acrylamide) hydrogel with TGF-ß3 loaded nanoparticles for cartilage repair: Biodegradability, biocompatibility and protein adsorption.

Current implantable materials are limited in terms of function as native tissue, and there is still no effective clinical treatment to restore articular impairments. Hereby, a functionalized polyacrylamide (PAAm)-alginate (Alg) Double Network (DN) hydrogel acting as an articular-like tissue is developed. These hydrogels sustain their mechanical stability under different temperature (+4 °C, 25 °C, 40 °C) and humidity conditions (60% and 75%) over 3 months. As for the functionalization, transforming growth factor beta-3 (TGF-ß3) encapsulated (NPTGF-ß3) and empty poly(lactide-co-glycolide) (PLGA) nanoparticles (PLGA NPs) are synthesized by using microfluidic platform, wherein the mean particle sizes are determined as 81.44 ± 9.2 nm and 126 ± 4.52 nm with very low polydispersity indexes (PDI) of 0.194 and 0.137, respectively. Functionalization process of PAAm-Alg hydrogels with ester-end PLGA NPs is confirmed by FTIR analysis, and higher viscoelasticity is obtained for functionalized hydrogels. Moreover, cartilage regeneration capability of these hydrogels is evaluated with in vitro and in vivo experiments. Compared with the PAAm-Alg hydrogels, functionalized formulations exhibit a better cell viability. Histological staining, and score distribution confirmed that proposed hydrogels significantly enhance regeneration of cartilage in rats due to stable hydrogel matrix and controlled release of TGF-ß3. These findings demonstrated that PAAm-Alg hydrogels showed potential for cartilage repair and clinical application.

Cytotoxic, antimicrobial and nitric oxide inhibitory activities of supercritical carbon dioxide extracted Prunus persica leaves.

Different parts of Prunus persica as fruits, flowers, leaves and kernels have been consumed with dietary and therapeutic purposes traditionally. During fruit production, remarkable amount of leaves which can hold important bioactive groups as phenolics, have been left unutilized. The aim of this study was to investigate cytotoxic, antimicrobial and nitric oxide inhibitory activities of supercritical carbondioxide extracts of Prunus persica leaves. Among studied cell lines, supercritical carbon dioxide extract which was processed at 150 bar, 60 °C, and 6% co-solvent ethanol, exhibited remarkable cytotoxic activity against HeLa, MPanc-96 and MCF-7 cell lines with IC50 values of 12.22 µg/ml, 28.17 µg/ml and 35.51 µg/ml respectively, whereas IC50 value of conventional solvent extract was above 50 µg/ml. Minimum inhibitory concentration values determined for antibacterial and antifungal activities against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium and Candida albicans were found as 62.50 µg/ml. Strong nitric oxide inhibition was achieved with IC50 of 9.30 µg/ml. The promising results revealed that Prunus persica leaves may have remarkable potential as supplement both for drug and food industries. This study is the first report revealing cytotoxic, antimicrobial and nitric oxide inhibitory activity of supercritical carbon dioxide extract of Prunus persica leaves.

Fabrication of Thymoquinone-Loaded Albumin Nanoparticles by Microfluidic Particle Synthesis and Their Effect on Planarian Regeneration.

Thymoquinone is the main bioactive component of the plant Nigella sativa, which is commonly known as black seeds and has several therapeutic effects. However, clinical applications of thymoquinone are limited due to its hydrophobic nature. In this study, thymoquinone is encapsulated in albumin nanoparticles by using a microfluidic platform to overcome this limitation. The mean particle sizes of empty and thymoquinone-loaded nanoparticles are determined as 271.3 and 315.6 nm, respectively, with polydispersity index values both lower than 0.25. In addition to particle size distribution measurements, characterizations of the prepared nanoparticles such as zeta potential measurements, in vitro release studies, as well as scanning electron microscopy, Fourier-transform infrared, and differential scanning calorimetry analyses are also carried out. To determine the effect of thymoquinone on neural regeneration, planarians are used as the model organism. After application of free and encapsulated thymoquinone, planarians are amputated and the fragments are observed in terms of head and tail regeneration, swimming pattern, and behavior. The results indicate that thymoquinone affects their behavior and primarily enhances head regeneration of planarians. In addition, it is shown that encapsulation of thymoquinone not only enhances the thermal stability of the molecule but also decreases its toxicity.

Optimization of microwave assisted extraction of Morus nigra L. fruits maximizing tyrosinase inhibitory activity with isolation of bioactive constituents.

Morus nigra L. is a beneficial food due to rich phenolic components. While aiming higher yields for bioactive constituents, reduction in terms of raw material, solvent, time and energy gained more importance to provide a sustainable life for human and nature. Microwave assisted extraction (MAE) of Morus nigra fruits was optimized in order to elicit process parameters maximizing bioactive metabolites and tyrosinase inhibitory activity. Spectrophotometry and UPLC-DAD-ESI-MS/MS systems were utilized for quantitative analysis of total phenol, flavonoid and anthocyanin contents. Optimum conditions for MAE were determined as 500 W, 35% ethanol, 10 min yielding 12.63 mg/g cya-3-glu equiv. anthocyanin and IC50 value of 1.60 mg/ml for tyrosinase inhibitory activity. Microwave extracts prevailed better outcomes compared to conventional extraction methods (10.93 mg/g content with IC50 of 2.81 mg/ml). MAE could be considered as an advanced technique to obtain extracts from Morus nigra fruits with higher bioactive content and activity.

Formulation of organic and inorganic hydrogel matrices for immobilization of ß-glucosidase in microfluidic platform.

The aim of this study was to formulate silica and alginate hydrogels for immobilization of ß-glucosidase. For this purpose, enzyme kinetics in hydrogels were determined, activity of immobilized enzymes was compared with that of free enzyme, and structures of silica and alginate hydrogels were characterized in terms of surface area and pore size. The addition of polyethylene oxide improved the mechanical strength of the silica gels and 68% of the initial activity of the enzyme was preserved after immobilizing into tetraethyl orthosilicate-polyethylene oxide matrix where the relative activity in alginate beads was 87%. The immobilized ß-glucosidase was loaded into glass-silicon-glass microreactors and catalysis of 4-nitrophenyl ß-d-glucopyranoside was carried out at various retention times (5, 10, and 15 min) to compare the performance of silica and alginate hydrogels as immobilization matrices. The results indicated that alginate hydrogels exhibited slightly better properties than silica, which can be utilized for biocatalysis in microfluidic platforms.

Cytotoxic and Nitric Oxide Inhibition Activities of Propolis Extract along with Microencapsulation by Complex Coacervation.

In this study, cytotoxicity of ethanol extract of propolis (EEP) originating from Sivas, Turkey was screened against several cancer cell lines, namely PC-3, U87MG, A-549, mPANC96, CaCo-2, MCF-7, HeLa, MDA-MB-231 and a non-tumor cell line HEK293 by MTT assay. The inhibition levels of inducible nitric oxide synthase (iNOS) were also determined by using RAW 264.7 macrophage cells following lipopolysaccharide (LPS) treatment. EEP exhibited significant cytotoxic nitric oxide inhibition activities with an IC50 value of 0.1 ± 0.1 µg/ml indicating a high potential as an anti-inflammatory agent. In spite of these promising results and the fact that propolis is a highly nutritive substance, its low solubility and bitter taste limit the applications as a natural supplement. Encapsulation might serve as a good strategy in order to overcome these problems. Complex coacervation was applied where the main focus was on surfactant type, polymer ratio (alginate:gelatin), stirring rate and concentration of core material. The mean particle size of unloaded microparticles were 22.62 µm obtained with gelatin:alginate ratio of 1:1 at a stirring rate of 1400 rpm with 2 ml of 1 % (w/v) sodium carboxymethyl cellulose (Na-CMC), whereas addition of EEP at a concentration of 100 mg/ml increased the mean particle size to 36.44 µm and yielded an encapsulation efficiency of 98.77 %. The cytotoxicities of EEP loaded microparticles were also assessed both on MCF-7 and MDA-MB-231 where similar results were achieved as free EEP which can enhance the possible use of propolis extract in the industry as a natural supplement.

Synthesis and characterization of cryogel structures for isolation of EPSs from Botryococcus braunii.

In this study, the objective was to separate exopolysaccharides (EPSs) released in the broth subsequent to outdoor cultivation of Botryococcus braunii. For this, poly(2-hydroxyethyl methacrylate) (PHEMA) cryogels were synthesized. After that, the surface was modified by coupling Concanavalin A. Box-Behnken statistical design was used to evaluate the effect of freezing temperature, Con A concentration and flow rate on Con A binding capacity. Optimum synthesis conditions were elicited as -14.48°C freezing temperature, 1.00mg/ml Con A concentration and 0.30ml/min flow rate yielding 3.18mg Con A/g cryogel, whereas -16°C, 1.00mg/ml and 0.30ml/min yielded the highest (3.38mg) binding capacity in experimental cryogel preparation. The EPS adsorption capacity of the optimum cryogel column was found as 3.26mg EPS/g cryogel corresponding to adsorption yield of 80%. Besides; swelling test, elemental analysis, Micro-CT, SEM and FTIR analysis were carried out for characterization of the synthesized cryogels.