Papers by sedef tamburacı
International Journal of Biological Macromolecules, 2019
POSS, regarded as the smallest silica particle, is widely used as nanofiller in polymer systems. ... more POSS, regarded as the smallest silica particle, is widely used as nanofiller in polymer systems. POSS-based nanocomposites are deduced as novel materials having potency for biomedical applications owing to the enhanced biocompatibility and physicochemical characteristics. The aim of this work was to integrate the beneficial features of chitosan (CS) and OctaTMA-POSS nanoparticle to design nanocomposite for bone tissue regeneration. The nanocomposite scaffolds were fabricated by freeze-drying. The effects of POSS incorporation on morphology and structure of CS matrix were examined. Bioactivity and osteogenic effects of the POSS nanoparticles were investigated with cytocompatibility, cell proliferation, alkaline phosphatase activity, osteocalcin production and biomineralization assays. POSS incorporation altered the surface morphology by increasing surface roughness. Nanocomposite scaffolds with 82–90% porosity exhibited an increase in compression modulus of scaffolds (78–107 kPa) compared to control CS group (56 kPa). Results indicated that CS-POSS scaffolds were found cytocompatible with 3T3, MG-63 and Saos-2 cell lines. POSS incorporation showed promising effects on osteoblast adhesion and proliferation as well as increasing ALP activity, octeocalcin secretion and biomineralization of cells.
International Journal of Biological Macromolecules , 2019
Polymer-based scaffolds have already gained popularity in many biomedical applications due to con... more Polymer-based scaffolds have already gained popularity in many biomedical applications due to convenient routes for fabrication and favourable structural, physicochemical and functional characteristics. However, polymeric scaffolds lack osteoconductivity and some synthetic polymers carry the risk of inflammatory response caused by degradation by-products. Those facts limit their practical use in bone tissue engineering. In this study, three-dimensional (3D) porous scaffolds from naturally derived polymer, namely regenerated cellulose, were prepared using a non-hydrolytic sol-gel and lyophilization techniques. To induce osteoconductive properties of the polymeric scaffolds, cuttlebone microparticles were immobilized and the surface coating was achieved via in vitro mineralization using 10-fold concentrated simulated body fluid (10x SBF). Biogenic activity of cuttlebone is explained by its chemical composition, which includes polysaccharide β-chitin and macro-, micro- and trace elements favourable for mineralization. Parallel the scaffolds were examined during long-term (24 weeks) in vitro mineralization in 1x SBF for the purpose to investigate apatite-forming ability of the scaffolds. A nice cauliflower-like structures and needle-like dents of the spherical aggregates, which are characteristic to hydroxyapatite precursors, were observed on the surface of cellulose/cuttlebone scaffolds by SEM. 10x SBF coating enhanced cell attachment to the scaffolds because SBF elements are known to increase bioactivity by inducing re-deposition of carbonate apatite crystallites on scaffold surface. Additionally, calcium and phosphate depositions were clearly observed on the developed scaffolds using von Kossa and Alizarin Red S staining. Proliferative and osteoconductive effects on the osteoblast-like MG-63 cells demonstrate the cellulose/cuttlebone scaffolds soaked in 10x SBF as a favourable material for bone tissue engineering.
ournal of Materials Science: Materials in Medicine , 2020
Recently, layered structures composed of nanofibers have gained attention as a novel material to ... more Recently, layered structures composed of nanofibers have gained attention as a novel material to mimic skin tissue in wound healing applications. The aim of this study is to develop a novel hybrid bilayer material composed of zein based composite film and nanofiber layers as a wound dressing material. The upper layer was composed of H. perforatum oil incorporated zein film including MMT and the bottom layer was comprised of 3D electrospun zein/MMT nanofibers to induce wound healing with the controlled release of H. perforatum oil. The bilayer composites were characterized in terms of mechanical test, WVP, water uptake and surface wettability. Antimicrobial activity of the wound dressings against microorganisms were investigated by disc diffusion method. In vitro cytotoxicity of monolayer film and bilayer structure was performed using WST-1 assay on HS2 keratinocyte and 3T3 cell lines. Results indicated that the prepared monolayer films showed appropriate mechanical and gas barrier properties and surface wettability for wound healing. Controlled release of H. perforatum oil was obtained from fabricated membranes up to 48 h. Bilayer membranes showed antimicrobial activity against E. coli, S. aureus, and C. albicans and did not show any toxic effect on NIH3T3 mouse fibroblast and HS2 keratinocyte cell lines. In vitro scratch assay results indicated that H. perforatum oil had a wound healing effect by inducing fibroblast migration. The proliferation study supported these results by increasing fibroblast proliferation on H. perforatum oil loaded bilayer membranes.
International Journal of Biological Macromolecules, 2019
Recently, biologically active natural macromolecules have come into prominence to be used as pote... more Recently, biologically active natural macromolecules have come into prominence to be used as potential mate- rials in scaffold design due to their unique characteristics which can mimic the human tissue structure with their physical and chemical similarity. Among them, fish scale (FS) is a biologically active material with its struc- tural similarity to bone tissue due to including type I collagen and hydroxyapatite and also have distinctive col- lagen arrangement. In the present study, it is aimed to design a novel composite scaffold with FS incorporation into chitosan (CH) matrix for bone tissue regeneration. Therefore, two biological macromolecules, fish scale and chitosan, were combined to produce bio-composite scaffold. First, FS were decellularized with the chemical method and disrupted physically as microparticles (100 μm), followed by dispersal in CH with ultrasonic homog- enisation, CH/FS scaffolds were fabricated by lyophilization technique. Scaffolds were characterized physically, chemically, mechanically, and morphologically. SEM and porosity results showed that CH/FS scaffolds have uni- form pore structure showing high porosity. Mechanical properties and degradation rate are enhanced with in- creasing FS content. In vitro cytotoxicity, proliferation and osteogenic activity of the scaffolds were evaluated with SaOS-2 cell line. CH/FS scaffolds did not show any cytotoxicity effect and the cells were gradually prolifer- ated during culture period. Cell viability results showed that, FS microparticles had a proliferative effect on SaOS-2 cells when compared to control group. ALP activity and biomineralization studies indicated that FS micro- particle reinforcement increased osteogenic activity during culture period. As a biological macromolecule with unique characteristics, FS was found as cytocompatible and provided promising effects as reinforcement agents for polymeric scaffolds. In conclusion, fabricated CH/FS bio-composites showed potential for bone tissue engi- neering applications.
ACS Applied Biomaterials, 2019
Osteochondral tissue is hard to regenerate after injuries or
degenerative diseases. Traditional t... more Osteochondral tissue is hard to regenerate after injuries or
degenerative diseases. Traditional treatments still have disadvantages,
such as donor tissue availability, donor site morbidity, implant loss, and
limited durability of prosthetics. Thus, recent studies have focused on
tissue engineering strategies to regenerate osteochondral defects with
different scaffold designs. Scaffolds have been developed from monolayer
structures to bilayer scaffolds to repair the cartilage−bone interface and
to support each tissue separately. In this study, Si-substituted nano-
hydroxyapatite particles (Si-nHap) and silica-based POSS nanocages
were used as reinforcements in different polymer layers to mimic a
cartilage−bone tissue interface. Chitosan and zein, which are widely used
biopolymers, are used as polymer layers to mimic the structure. This
study reports the development of a bilayer scaffold produced via
fabrication of two different nanocomposite layers with different polymer-inorganic composites in order to satisfy the complex and diverse regenerative requirements of osteochondral tissue. The chitosan/Si-nHap microporous layer and the zein/POSS nanofiber layer were designed to mimic a bone−cartilage tissue interface. Bilayer scaffolds were characterized with SEM, compression, swelling, and biodegradation tests to determine morphological, physical, and mechanical properties. The results showed that the bilayer scaffold had a structure composed of microporous and nanofiber layers joined at a continuous interface with appropriate mechanical properties. Furthermore, in vitro cell culture studies have been performed with LDH, proliferation, fluorescence imaging, and ALP activity assays using osteosarcoma and chondrosarcoma cell lines. ALP expression levels provide a good illustration of the improved osteogenic potential of a porous chitosan/Si-nHap layer due to the Si-doped nHap incorporation. Histological data showed that both fiber and porous layers that mimic the cartilage and bone sections exhibit homogeneous cell distribution and matrix formation. Histochemical staining was used to determine the cell proliferation and ECM formation on each layer. In vitro studies indicated that zein-POSS/chitosan/Si-nHap nanocomposite bilayer scaffolds showed promising results for osteochondral regeneration.
Materials Science & Engineering C, 2019
Recently, natural polymers are reinforced with silica particles for hard tissue engineering appli... more Recently, natural polymers are reinforced with silica particles for hard tissue engineering applications to induce bone regeneration. In this study, as two novel bioactive agents, effects of diatomite and polyhedral oligomeric silsesquioxanes (POSS) on chitosan (CS)/Na-carboxymethylcellulose (Na-CMC) polymer blend scaffolds are examined. In addition, the effect of silica reinforcements was compared with Si-substituted nano-hydroxyapatite (Si-Hap) particles. The morphology, physical and chemical structures of the scaffolds were characterized with SEM, liquid displacement, FT-IR, mechanical analysis, swelling and degradation studies. The particle size and the crystal structure of diatomite, POSS and Si-Hap particles were determined with DLS and XRD analyses. In vitro studies were performed to figure out the cytotoxicity, proliferation, ALP activity, osteocalcin production and biomineralization to demonstrate the promising use of natural silica particles in bone regeneration. Freeze- dried scaffolds showed 190–307 μm pore size range and 61–70% porosity. Both inorganic reinforcements in- creased the mechanical strength, enhanced the water uptake capacity and fastened the degradation rate. The nanocomposite scaffolds did not show any cytotoxic effect and enhanced the surface mineralization in osteo- genic medium. Thus, diatomite and POSS cage structures can be potential reinforcements for nanocomposite design in hard tissue engineering applications.
Biomedical Materials, 2019
Despite the advancements in bone transplantation operations, inflammation is still a serious prob... more Despite the advancements in bone transplantation operations, inflammation is still a serious problem that threatens human health at the post-implantation period. Conventional antibiotic therapy methods may lead to some side effects such as ototoxicity and nephrotoxicity, especially when applied in high doses. Therefore, local drug delivery systems play a vital role in bone disorders due to the elimination of the disadvantages introduced by conventional methods. In the presented study, it was aimed to develop Vancomycin (VC) and Gentamicin (GC) loaded chitosan-montmorillonite nanoclay composites (CS/MMT) to provide required antibiotic doses to combat post-implantation infection. CS/MMT nanocomposite formation was supplied by microfluidizer homogenization and spherical drug carrier nanoparticles were obtained by electrospraying technique. Three factors; voltage, distance and flowrate were varied to fabricate spherical nanoparticles with uniform size. Emprical model was developed to predict nanosphere size by altering process variables. Nanospheres were characterized in terms of morphology, hydrodynamic size, zeta potential, drug encapsulation efficiency and release profile. Drug loaded nanospheres have been successfully produced with a
size range of 180–350 nm. Nanocomposite drug carriers showed high encapsulation efficiency (80%–95%) and prolonged release period when compared to bare chitosan nanospheres. The drug release from nanocomposite carriers was monitored by diffusion mechanism up to 30 d. The in vitro release medium of nanospheres showed strong antimicrobial activity against gram-positive S. aureus and gram-negative E. coli bacteria. Furthermore, it was found that the nanospheres did not show any cytotoxic effect to fibroblast (NIH/3T3) and osteoblast (SaOS-2) cell lines. The results demonstrated that the prepared composite nanospheres can be a promising option for bone infection prevention at the post implantation period.
Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2018
Recently, functional multilayer scaffolds with con- trolled drug release ability come into promin... more Recently, functional multilayer scaffolds with con- trolled drug release ability come into prominence for wound healing applications to mimic the layered structure of skin tis- sue and prevent the possible infections at the defect site. In this study, controlled antibiotic releasing zein bilayer mem- branes were fabricated for treatment of acute skin infections. Gentamicin loaded fibers were prepared by electrospinning on the membrane surface. Membranes were characterized with scanning electron microscope, atomic force microscopy, Fourier transform infrared spectroscopy, contact angle, mechanical analysis, swelling, degradation, and water vapor permeability studies. In vitro cytotoxicity, cell attachment, and proliferation were investigated. Cell attachment on fiber layer was observed with fluorescence imaging. Fabricated fibers showed structural similarity to the skin tissue layers with a fiber diameter range of 350–425 nm and film thickness in the range of 311–361 μm. Mechanical properties were found com- patible with the skin tissue. In addition, membranes showed antimicrobial activity against Staphylococcus aureus and Escherichia coli. The sustained release was achieved with a cumulative release of 94%. Membranes did not show any cyto- toxic effect. NIH/3T3 and HS2 cell lines were proliferated on each layer mimicking the multilayer skin tissue. Hence, zein- based bilayer membrane showed promising properties to be used as a potential antimicrobial wound dressing for skin tis- sue regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: 00B: 000–000, 2018.
Journal of Biomaterials Applications, 2018
Recently, usage of marine-derived materials in biomedical field has come into prominence due to t... more Recently, usage of marine-derived materials in biomedical field has come into prominence due to their promising character- istics such as biocompatibility, low immunogenicity and wide accessibility. Among these marine sources, cuttlebone has been used as a valuable component with its trace elemental composition in traditional medicine. Recent studies have focused on the use of cuttlebone as a bioactive agent for tissue engineering applications. In this study, hydroxyapatite particles were obtained by hydrothermal synthesis of cuttlebone and incorporated to cellulose scaffolds to fabricate an osteoconductive composite scaffold for bone regeneration. Elemental analysis of raw cuttlebone material from different coastal zones and cuttlebone-derived HAp showed that various macro-, micro- and trace elements – Ca, P, Na, Mg, Cu, Sr, Cl, K, S, Br, Fe and Zn were found in a very similar amount. Moreover, biologically unfavorable heavy metals, such as Ag, Cd, Pb or V, were not detected in any cuttlebone specimen. Carbonated hydroxyapatite particle was further synthesized from cuttlebone microparticles via hydrothermal treatment and used as a mineral filler for the preparation of cellulose- based composite scaffolds. Interconnected highly porous structure of the scaffolds was confirmed by micro-computed tomography. The mean pore size of the scaffolds was 510 mm with a porosity of 85%. The scaffolds were mechanically characterized with a compression test and cuttlebone-derived HAp incorporation enhanced the mechanical properties of cellulose scaffolds. In vitro cell culture studies indicated that MG-63 cells proliferated well on scaffolds. In addition, cuttlebone-derived hydroxyapatite significantly induced the ALP activity and osteocalcin secretion. Besides, HAp incorpo- ration increased the surface mineralization which is the major step for bone tissue regeneration.
Novel phytochemical Cissus quadrangularis extract–loaded chitosan/Na-carboxymethyl cellulose–based scaffolds for bone regeneration, 2018
Medicinal plants are attracting considerable interest as a potential therapeutic agent for bone t... more Medicinal plants are attracting considerable interest as a potential therapeutic agent for bone tissue regeneration. Cissus quadrangularis L. is also a medicinal plant known with its osteogenic activity. In this study, a phytochemical scaffold was produced by incorporating Cissus quadrangularis with chitosan/Na-carboxymethyl cellulose blend by lyophilization technique. The effect of Cissus quadrangularis loading on the mechanical, morphological, chemical, and degradation properties as well as in vitro cytotoxicity, cell proliferation, and differentiation of the composites was investigated. Scanning electron microscopy images showed that porous Cissus quadrangularis– loaded scaffolds were obtained with an average pore size of 148–209μm which is appropriate for bone regeneration. Cissus quadrangularis incorporation enhanced the compression modulus of scaffolds from 76 to 654 kPa. In vitro cell culture results indicated that Cissus quadrangularis/ chitosan/Na-carboxymethyl cellulose scaffolds provided a favorable substrate for the osteoblast adhesion, proliferation, and mineralization. Results supported the osteoinductive property of the Cissus quadrangularis extract–incorporated scaffolds even without osteogenic media supplement. Cissus quadrangularis extract increased the alkaline phosphatase activity of the SaOS-2 cells on scaffolds on 7th and 14th days of incubation. The investigation of characterization and cell culture studies suggest that Cissus quadrangularis–loaded osteoinductive Cissus quadrangularis/ chitosan/Na-carboxymethyl cellulose scaffold can serve as a potential biomaterial for bone tissue engineering applications.
A B S T R A C T As a natural and abundant silica mineral, diatomite particles (SiO 2-nH 2 O) have... more A B S T R A C T As a natural and abundant silica mineral, diatomite particles (SiO 2-nH 2 O) have been used in several areas such as filtration, photonics, sound and heat insulation, filler material and drug delivery due to its abundance, inexpensive cost, unique morphology and porous structure. But up to date, diatomite incorporated silica based scaffolds have not been used for bone tissue engineering applications. In the present study, the goal was to combine the useful biomaterial properties of both chitosan and diatomite as biocomposite organic/inorganic biomaterial for bone tissue engineering applications and optimize the silica content of the composites in order to obtain optimum morphological structure, high mechanical properties, enlarged surface area and enhanced cell proliferation. The effect of silica loading on the mechanical, morphological, chemical, and surface properties, wettability and biocompatibility of composite scaffolds were investigated. In addition, in vitro cytotoxicity and cellular activities including cell proliferation, ALP activity and biomineralization were investigated in order to determine biological activity of the composite scaffolds. Diatomite particles lead to enhancement in the water uptake capacity of scaffolds. Chitosan-silica composites exhibited 82–90% porosity. Wet chitosan-silica composite scaffolds exhibited higher compression moduli when compared to pure chitosan scaffold in the range of 67.3–90.1 kPa. Average pore size range of chitosan-diatomite composite scaffolds was obtained as 218-319 μm. In vitro results indicated that chitosan-diatomite composites did not show any cytotoxic effect on 3T3, MG-63 and Saos-2 cell lines. Scaffolds were found to be favorable for osteoblast proliferation. Diatomite incorporation showed promising effects on enhancing ALP activity as well as mineral formation on scaffold surface. Thus, the prepared scaffolds in this study can be considered prospective material for bone tissue engineering applications.
Context: Algae have gained importance in cosmeceutical product development due to their beneficia... more Context: Algae have gained importance in cosmeceutical product development due to their beneficial effects on skin health and therapeutical value with bioactive compounds. Spirulina platensis Parachas (Phormidiaceae) is renowned as a potential source of high-value chemicals and recently used in skincare products.
Objective: This study develops and evaluates skin creams incorporated with bioactive S. platensis extract.
Materials and methods: Spirulina platensis was cultivated, the aqueous crude extract was prepared and in vitro cytotoxicity of S. platensis extract in the range of 0.001–1% concentrations for 1, 3 and 7 d on HS2
keratinocyte cells was determined. Crude extracts were incorporated in skin cream formulation at 0.01% (w/w) concentration and in vitro wound healing and genotoxicity studies were performed.
Immunohistochemical staining was performed to determine the collagen activity.
Results: 0.1% S. platensis extract exhibited higher proliferation activity compared with the control group with 198% of cell viability after 3 d. Skin cream including 1.125% S. platensis crude extract showed
enhanced wound healing effect on HS2 keratinocyte cell line and the highest HS2 cell viability % was obtained with this concentration. The micronucleus (MN) assay results indicated that S. platensis extract
incorporated creams had no genotoxic effect on human peripheral blood cells. Immunohistochemical analysis showed that collagen 1 immunoreactivity was improved by increased extract concentration and it was strongly positive in cells treated with 1.125% extract incorporated skin cream.
Conclusions: The cell viability, wound healing activity and genotoxicity results showed that S. platensis incorporated skin cream could be of potential value in cosmeceutical and biomedical applications.
In this study, novel composites membranes composed of chitosan matrix and polyhedral oligomeric s... more In this study, novel composites membranes composed of chitosan matrix and polyhedral oligomeric silsesquioxanes (POSS) were fabricated by solvent casting method. The effect of POSS loading on the mechanical, morphological, chemical, thermal and surface properties, and cytocompatibility of composite membranes were investigated and observed by tensile test, atomic force microscopy (AFM), Fourier transform infrared spectro-scopy (FTIR), thermal gravimetric analysis (TGA), protein adsorption assay, air/water contact angle analysis and WST-1 respectively. Swelling studies were also performed by water absorption capacity determination. Results showed that incorporation of Octa-TMA POSS ® nanofiller to the chitosan matrix increased the surface roughness, protein adsorption and swelling capacity of membranes. The addition of POSS enhanced significantly the ultimate tensile strength and strain at break of the composite membranes up to 3 wt% POSS loaded samples. An increase of about 76% in tensile strength and of strain at break 1.28% was achieved for 3 wt% POSS loaded nanocomposite membranes compared with chitosan membranes. The presence of POSS filler into polymer matrix increased the plasma protein adsorption on the surface. Maximum protein capacity and swelling was obtained for 10 wt% loaded samples. High cell viability results were obtained with indirect extraction of chitosan/POSS composites. Besides, cell proliferation and ALP activity results showed that POSS incorporation significantly increased the ALP activity of Saos-2 cells cultured on chitosan membranes. This novel composite membranes with tunable properties could be considered as a potential candidate for guided bone regeneration applications. Graphical abstract
Journal of materials science. Materials in medicine, 2017
In this study, novel composites membranes composed of chitosan matrix and polyhedral oligomeric s... more In this study, novel composites membranes composed of chitosan matrix and polyhedral oligomeric silsesquioxanes (POSS) were fabricated by solvent casting method. The effect of POSS loading on the mechanical, morphological, chemical, thermal and surface properties, and cytocompatibility of composite membranes were investigated and observed by tensile test, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), protein adsorption assay, air/water contact angle analysis and WST-1 respectively. Swelling studies were also performed by water absorption capacity determination. Results showed that incorporation of Octa-TMA POSS® nanofiller to the chitosan matrix increased the surface roughness, protein adsorption and swelling capacity of membranes. The addition of POSS enhanced significantly the ultimate tensile strength and strain at break of the composite membranes up to 3 wt% POSS loaded samples. An increase of about 76% in tens...
Context: Algae have gained importance in cosmeceutical product development due to their beneficia... more Context: Algae have gained importance in cosmeceutical product development due to their beneficial effects on skin health and therapeutical value with bioactive compounds. Spirulina platensis Parachas (Phormidiaceae) is renowned as a potential source of high-value chemicals and recently used in skincare products.
Objective: This study develops and evaluates skin creams incorporated with bioactive S. platensis extract. Materials and methods: Spirulina platensis was cultivated, the aqueous crude extract was prepared and in vitro cytotoxicity of S. platensis extract in the range of 0.001–1% concentrations for 1, 3 and 7 d on HS2 keratinocyte cells was determined. Crude extracts were incorporated in skin cream formulation at 0.01% (w/w) concentration and in vitro wound healing and genotoxicity studies were performed. Immunohistochemical staining was performed to determine the collagen activity.
Results: 0.1% S. platensis extract exhibited higher proliferation activity compared with the control group with 198% of cell viability after 3d. Skin cream including 1.125% S. platensis crude extract showed enhanced wound healing effect on HS2 keratinocyte cell line and the highest HS2 cell viability % was obtained with this concentration. The micronucleus (MN) assay results indicated that S. platensis extract incorporated creams had no genotoxic effect on human peripheral blood cells. Immunohistochemical ana- lysis showed that collagen 1 immunoreactivity was improved by increased extract concentration and it was strongly positive in cells treated with 1.125% extract incorporated skin cream.
Conclusions: The cell viability, wound healing activity and genotoxicity results showed that S. platensis incorporated skin cream could be of potential value in cosmeceutical and biomedical applications.
In this study, natural silica source, diatomite, incorporated novel chitosan based composite memb... more In this study, natural silica source, diatomite, incorporated novel chitosan based composite membranes were fabricated and characterized for bone tissue engineering applications as possible bone regeneration membrane. The effect of diatomite loading on the mechanical, morphological, chemical, thermal and surface properties, wettabil-ity and in vitro cytotoxicity and cell proliferation on of composite membranes were investigated and observed by tensile test, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), protein adsorption assay, air/water contact angle analysis and WST-1 respectively. Swelling studies were also performed by water absorption capacity determination. Results showed that incorporation of diat-omite to the chitosan matrix increased the surface roughness, swelling capacity and tensile modulus of membranes. An increase of about 52% in Young's modulus was achieved for 10 wt% diatomite composite membranes compared with chitosan membranes. High cell viability results were obtained with indirect extraction method. Besides, in vitro cell proliferation and ALP activity results showed that diatom incorporation significantly increased the ALP activity of Saos-2 cells cultured on chitosan membranes. The novel composite membranes prepared in the present study with tunable properties can be considered as a potential candidate as a scaffold in view of its enhanced physical & chemical properties as well as biological activities for bone tissue engineering applications.
Abstract: There is considerable interest in cyanobacteria as sources of antioxidant pigments, ant... more Abstract: There is considerable interest in cyanobacteria as sources of antioxidant pigments, antiinflammatory substances, enzymes such as superoxide dismutase (SOD) and vitamins. Antioxidant enzymes have significant role in the removal of reactive oxygen species produced during visible and ultraviolet irradiance stress in cyanobacteria. One of the most ubiquitous protective enzyme is superoxide dismutase (SOD). Most of cyanobacteria are known to have both FeSOD and MnSOD which are associated with photosystem I and II. These enzymes are responsible for scavenging superoxide radicals.Spirulina platensis and Synechococcus nidulans are widely used cyanobacteria as food supplement and cosmetic due to their bioactive compounds. Although the chemical composition of S.platensis has been investigated by many researchers, research on the relationship between protein content and comparison of SOD activity with other cyanobacteria is limited.Among several SOD producing cyanobacteria, the most promising organisms were investigate in terms of SOD activities in this study. The aim of the present work was to investigate and compare the SOD activities of different cyanobacteria including S. platensis, Pseudanabeana sp., S. nidulans and associate with protein contents. SOD activities of these cyanobacteria were determined by xanthine/xanthineoxidase method.Modified Lowry method was used for protein determination. The analysis results showed that the maximum specific SOD activity obtained was 50.4 U/mg from S.nidulans and the minimum specific SOD activity was 18.4 U/mg from Pseudanabeana sp. Total protein amount of S. nidulans, S. platensis, Pseudanabeana sp. was determined as 0.25 mg/ml, 0.27 mg/ml and 0.43 mg/ml respectively. As a result, Synechococcus nidulans was more efficient at scavenging peroxide radicals than Pseudanabeana sp.
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Papers by sedef tamburacı
degenerative diseases. Traditional treatments still have disadvantages,
such as donor tissue availability, donor site morbidity, implant loss, and
limited durability of prosthetics. Thus, recent studies have focused on
tissue engineering strategies to regenerate osteochondral defects with
different scaffold designs. Scaffolds have been developed from monolayer
structures to bilayer scaffolds to repair the cartilage−bone interface and
to support each tissue separately. In this study, Si-substituted nano-
hydroxyapatite particles (Si-nHap) and silica-based POSS nanocages
were used as reinforcements in different polymer layers to mimic a
cartilage−bone tissue interface. Chitosan and zein, which are widely used
biopolymers, are used as polymer layers to mimic the structure. This
study reports the development of a bilayer scaffold produced via
fabrication of two different nanocomposite layers with different polymer-inorganic composites in order to satisfy the complex and diverse regenerative requirements of osteochondral tissue. The chitosan/Si-nHap microporous layer and the zein/POSS nanofiber layer were designed to mimic a bone−cartilage tissue interface. Bilayer scaffolds were characterized with SEM, compression, swelling, and biodegradation tests to determine morphological, physical, and mechanical properties. The results showed that the bilayer scaffold had a structure composed of microporous and nanofiber layers joined at a continuous interface with appropriate mechanical properties. Furthermore, in vitro cell culture studies have been performed with LDH, proliferation, fluorescence imaging, and ALP activity assays using osteosarcoma and chondrosarcoma cell lines. ALP expression levels provide a good illustration of the improved osteogenic potential of a porous chitosan/Si-nHap layer due to the Si-doped nHap incorporation. Histological data showed that both fiber and porous layers that mimic the cartilage and bone sections exhibit homogeneous cell distribution and matrix formation. Histochemical staining was used to determine the cell proliferation and ECM formation on each layer. In vitro studies indicated that zein-POSS/chitosan/Si-nHap nanocomposite bilayer scaffolds showed promising results for osteochondral regeneration.
size range of 180–350 nm. Nanocomposite drug carriers showed high encapsulation efficiency (80%–95%) and prolonged release period when compared to bare chitosan nanospheres. The drug release from nanocomposite carriers was monitored by diffusion mechanism up to 30 d. The in vitro release medium of nanospheres showed strong antimicrobial activity against gram-positive S. aureus and gram-negative E. coli bacteria. Furthermore, it was found that the nanospheres did not show any cytotoxic effect to fibroblast (NIH/3T3) and osteoblast (SaOS-2) cell lines. The results demonstrated that the prepared composite nanospheres can be a promising option for bone infection prevention at the post implantation period.
Objective: This study develops and evaluates skin creams incorporated with bioactive S. platensis extract.
Materials and methods: Spirulina platensis was cultivated, the aqueous crude extract was prepared and in vitro cytotoxicity of S. platensis extract in the range of 0.001–1% concentrations for 1, 3 and 7 d on HS2
keratinocyte cells was determined. Crude extracts were incorporated in skin cream formulation at 0.01% (w/w) concentration and in vitro wound healing and genotoxicity studies were performed.
Immunohistochemical staining was performed to determine the collagen activity.
Results: 0.1% S. platensis extract exhibited higher proliferation activity compared with the control group with 198% of cell viability after 3 d. Skin cream including 1.125% S. platensis crude extract showed
enhanced wound healing effect on HS2 keratinocyte cell line and the highest HS2 cell viability % was obtained with this concentration. The micronucleus (MN) assay results indicated that S. platensis extract
incorporated creams had no genotoxic effect on human peripheral blood cells. Immunohistochemical analysis showed that collagen 1 immunoreactivity was improved by increased extract concentration and it was strongly positive in cells treated with 1.125% extract incorporated skin cream.
Conclusions: The cell viability, wound healing activity and genotoxicity results showed that S. platensis incorporated skin cream could be of potential value in cosmeceutical and biomedical applications.
Objective: This study develops and evaluates skin creams incorporated with bioactive S. platensis extract. Materials and methods: Spirulina platensis was cultivated, the aqueous crude extract was prepared and in vitro cytotoxicity of S. platensis extract in the range of 0.001–1% concentrations for 1, 3 and 7 d on HS2 keratinocyte cells was determined. Crude extracts were incorporated in skin cream formulation at 0.01% (w/w) concentration and in vitro wound healing and genotoxicity studies were performed. Immunohistochemical staining was performed to determine the collagen activity.
Results: 0.1% S. platensis extract exhibited higher proliferation activity compared with the control group with 198% of cell viability after 3d. Skin cream including 1.125% S. platensis crude extract showed enhanced wound healing effect on HS2 keratinocyte cell line and the highest HS2 cell viability % was obtained with this concentration. The micronucleus (MN) assay results indicated that S. platensis extract incorporated creams had no genotoxic effect on human peripheral blood cells. Immunohistochemical ana- lysis showed that collagen 1 immunoreactivity was improved by increased extract concentration and it was strongly positive in cells treated with 1.125% extract incorporated skin cream.
Conclusions: The cell viability, wound healing activity and genotoxicity results showed that S. platensis incorporated skin cream could be of potential value in cosmeceutical and biomedical applications.
degenerative diseases. Traditional treatments still have disadvantages,
such as donor tissue availability, donor site morbidity, implant loss, and
limited durability of prosthetics. Thus, recent studies have focused on
tissue engineering strategies to regenerate osteochondral defects with
different scaffold designs. Scaffolds have been developed from monolayer
structures to bilayer scaffolds to repair the cartilage−bone interface and
to support each tissue separately. In this study, Si-substituted nano-
hydroxyapatite particles (Si-nHap) and silica-based POSS nanocages
were used as reinforcements in different polymer layers to mimic a
cartilage−bone tissue interface. Chitosan and zein, which are widely used
biopolymers, are used as polymer layers to mimic the structure. This
study reports the development of a bilayer scaffold produced via
fabrication of two different nanocomposite layers with different polymer-inorganic composites in order to satisfy the complex and diverse regenerative requirements of osteochondral tissue. The chitosan/Si-nHap microporous layer and the zein/POSS nanofiber layer were designed to mimic a bone−cartilage tissue interface. Bilayer scaffolds were characterized with SEM, compression, swelling, and biodegradation tests to determine morphological, physical, and mechanical properties. The results showed that the bilayer scaffold had a structure composed of microporous and nanofiber layers joined at a continuous interface with appropriate mechanical properties. Furthermore, in vitro cell culture studies have been performed with LDH, proliferation, fluorescence imaging, and ALP activity assays using osteosarcoma and chondrosarcoma cell lines. ALP expression levels provide a good illustration of the improved osteogenic potential of a porous chitosan/Si-nHap layer due to the Si-doped nHap incorporation. Histological data showed that both fiber and porous layers that mimic the cartilage and bone sections exhibit homogeneous cell distribution and matrix formation. Histochemical staining was used to determine the cell proliferation and ECM formation on each layer. In vitro studies indicated that zein-POSS/chitosan/Si-nHap nanocomposite bilayer scaffolds showed promising results for osteochondral regeneration.
size range of 180–350 nm. Nanocomposite drug carriers showed high encapsulation efficiency (80%–95%) and prolonged release period when compared to bare chitosan nanospheres. The drug release from nanocomposite carriers was monitored by diffusion mechanism up to 30 d. The in vitro release medium of nanospheres showed strong antimicrobial activity against gram-positive S. aureus and gram-negative E. coli bacteria. Furthermore, it was found that the nanospheres did not show any cytotoxic effect to fibroblast (NIH/3T3) and osteoblast (SaOS-2) cell lines. The results demonstrated that the prepared composite nanospheres can be a promising option for bone infection prevention at the post implantation period.
Objective: This study develops and evaluates skin creams incorporated with bioactive S. platensis extract.
Materials and methods: Spirulina platensis was cultivated, the aqueous crude extract was prepared and in vitro cytotoxicity of S. platensis extract in the range of 0.001–1% concentrations for 1, 3 and 7 d on HS2
keratinocyte cells was determined. Crude extracts were incorporated in skin cream formulation at 0.01% (w/w) concentration and in vitro wound healing and genotoxicity studies were performed.
Immunohistochemical staining was performed to determine the collagen activity.
Results: 0.1% S. platensis extract exhibited higher proliferation activity compared with the control group with 198% of cell viability after 3 d. Skin cream including 1.125% S. platensis crude extract showed
enhanced wound healing effect on HS2 keratinocyte cell line and the highest HS2 cell viability % was obtained with this concentration. The micronucleus (MN) assay results indicated that S. platensis extract
incorporated creams had no genotoxic effect on human peripheral blood cells. Immunohistochemical analysis showed that collagen 1 immunoreactivity was improved by increased extract concentration and it was strongly positive in cells treated with 1.125% extract incorporated skin cream.
Conclusions: The cell viability, wound healing activity and genotoxicity results showed that S. platensis incorporated skin cream could be of potential value in cosmeceutical and biomedical applications.
Objective: This study develops and evaluates skin creams incorporated with bioactive S. platensis extract. Materials and methods: Spirulina platensis was cultivated, the aqueous crude extract was prepared and in vitro cytotoxicity of S. platensis extract in the range of 0.001–1% concentrations for 1, 3 and 7 d on HS2 keratinocyte cells was determined. Crude extracts were incorporated in skin cream formulation at 0.01% (w/w) concentration and in vitro wound healing and genotoxicity studies were performed. Immunohistochemical staining was performed to determine the collagen activity.
Results: 0.1% S. platensis extract exhibited higher proliferation activity compared with the control group with 198% of cell viability after 3d. Skin cream including 1.125% S. platensis crude extract showed enhanced wound healing effect on HS2 keratinocyte cell line and the highest HS2 cell viability % was obtained with this concentration. The micronucleus (MN) assay results indicated that S. platensis extract incorporated creams had no genotoxic effect on human peripheral blood cells. Immunohistochemical ana- lysis showed that collagen 1 immunoreactivity was improved by increased extract concentration and it was strongly positive in cells treated with 1.125% extract incorporated skin cream.
Conclusions: The cell viability, wound healing activity and genotoxicity results showed that S. platensis incorporated skin cream could be of potential value in cosmeceutical and biomedical applications.