2023
Thrombogenesis is an important issue that causes blood-contacting biomedical device failure. This study focuses on hemocompatibility studies of novel blood-contacting polyelectrolyte complexes (PECs) for biomedical application designs. PEC films were fabricated from biobased polymers of silk fibroin (SF), chitosan (CH), and sodium alginate (AL) through the solvent casting method as well as Layer-by-Layer (LbL) technique. Characterization was carried out by Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), and Differential scanning calorimetry (DSC) analyses. FTIR spectra displayed all layers’ characteristic peaks of SF, CH, and AL. AFM images indicated that the addition of AL as an outer layer increased surface roughness. DSC analysis suggested that the best thermal stability has been observed with the CH outer layer of PECs. SEM micrograph analysis indicated that the morphologies of PECs were affected by the inclusion of the clopidogrel bisulfate (CLB). Hemocompatibility properties were investigated by complete blood count (CBC), prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (APTT), platelet adhesion, erythrocyte morphology analysis, in vitro cholesterol, and albumin level tests. These hemocompatibility analyses demonstrated that the PEC surfaces provide favourable principles to design and develop non-thrombogenic PECs for blood-contacting biomedical applications
2023
Due to their unique physicochemical properties, graphene and its derivatives are widely exploited for biomedical applications. It has been shown that graphene may exert different degrees of toxicity in in vivo or in vitro models when administered via different routes and penetrated through physiological barriers, subsequently being distributed within tissues or located within cells. In this study, in vitro neurotoxicity of graphene with different surface areas (150 and 750 m2/g) was examined on dopaminergic neuron model cells. SH-SY5Y cells were treated with graphene possessing two different surface areas (150 and 750 m2/g) in different concentrations between 400 and 3.125 μg/mL, and the cytotoxic and genotoxic effects were investigated. Both sizes of graphene have shown increased cell viability in decreasing concentrations. Cell damage increased with higher surface area. Lactate dehydrogenase (LDH) results have concluded that the viability loss of the cells is not through membrane damage. Neither of the two graphene types showed damage through lipid peroxidation (MDA) oxidative stress pathway. Glutathione (GSH) values increased within the first 24 and 48 h for both types of graphene. This increase suggests that graphene has an antioxidant effect on the SH-SY5Y model neurons. Comet analysis shows that graphene does not show genotoxicity on either surface area. Although there are many studies on graphene and its derivatives on their use with different cells in the literature, there are conflicting results in these studies, and most of the literature is focused on graphene oxide. Among these studies, no study examining the effect of graphene surface areas on the cell was found. Our study contributes to the literature in terms of examining the cytotoxic and genotoxic behavior of graphene with different surface areas.
2021
The blood–brain barrier (BBB) is a highly selective cellular monolayer unique to the microvasculature of the central nervous system (CNS), and it mediates the communication of the CNS with the rest of the body by regulating the passage of molecules into the CNS microenvironment. Limitation of passage of substances through the BBB is mainly due to tight junctions (TJ) and adherens junctions (AJ) between brain microvascular endothelial cells. The importance of actin filaments and microtubules in establishing and maintaining TJs and AJs has been indicated; however, recent studies have shown that intermediate filaments are also important in the formation and function of cell–cell junctions. The most common intermediate filament protein in endothelial cells is vimentin. Vimentin plays a role in blood–brain barrier permeability in both cell–cell and cell–matrix interactions by affecting the actin and microtubule reorganization and by binding directly to VE-cadherin or integrin proteins. The BBB permeability increases due to the formation of stress fibers and the disruption of VE–cadherin interactions between two neighboring cells in various diseases, disrupting the fiber network of intermediate filament vimentin in different ways. Intermediate filaments may be long ignored key targets in regulation of BBB permeability in health and disease.
2021
The blood–brain barrier (BBB) is a highly selective cellular monolayer unique to the microvasculature of the central nervous system (CNS), and it mediates the communication of the CNS with the rest of the body by regulating the passage of molecules into the CNS microenvironment. Limitation of passage of substances through the BBB is mainly due to tight junctions (TJ) and adherens junctions (AJ) between brain microvascular endothelial cells. The importance of actin filaments and microtubules in establishing and maintaining TJs and AJs has been indicated; however, recent studies have shown that intermediate filaments are also important in the formation and function of cell–cell junctions. The most common intermediate filament protein in endothelial cells is vimentin. Vimentin plays a role in blood–brain barrier permeability in both cell–cell and cell–matrix interactions by affecting the actin and microtubule reorganization and by binding directly to VE-cadherin or integrin proteins. The BBB permeability increases due to the formation of stress fibers and the disruption of VE–cadherin interactions between two neighboring cells in various diseases, disrupting the fiber network of intermediate filament vimentin in different ways. Intermediate filaments may be long ignored key targets in regulation of BBB permeability in health and disease.
2021
Bacterial cellulose (BC) produced by certain bacteria has the potential to be used in many different areas. Despite its advantageous properties such as high purity, mechanical strength, nanofiber mesh structure, and high-water holding capacity, its production through a biotechnological process prevents it from competing with vegetable cellulose in terms of cost-effectiveness. Therefore, studies associated with BC can be divided in two categories which are development cost effective BC production methods and culture media, and production of high value-added products from BC. In this study, it was aimed to develop a taurine-loaded moisturizing facial mask with antioxidant properties based on BC's high-water retention and chemical retention capacity. BC facial mask samples were characterized by Scanning Electron Microscopy (SEM) imaging, Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), Liquid Chromatography–Mass spectrometry (LC-MS), microbial, and mechanical stability tests. According to our results, produced facial mask samples do not show any cytotoxic effect on neither human keratinocyte (HS2) nor mouse fibroblast (L-929) cell lines, it has high thermal stability which making it suitable for different sterilization techniques including sterilization by heat treatment. Taurine release (over 2µg/ml in 5 min) and microbial stability tests (no bacterial growth observed) of packaged products kept at 40 and 25 °C for 6 months have shown that the product preserves its characteristics for a long time. In conclusion “bacterial cellulose-based facial masks" are suitable for use as a facial mask, and they can be used for moisturizing and antioxidant properties by means of taurine.
2021
Blood-brain barrier (BBB), although very important for protection of brain from major neurotoxins, negatively affects the treatment of central nervous system diseases by limiting the passage of neuropharmaceuticals from blood to the brain. Thus, researchers have to investigate the passage of the produced drug molecules through the BBB before they are introduced to the market. Although these experiments have been traditionally performed on experimental animals, drug permeability tests are now carried out mostly by in vitro BBB models due to ethical problems, differences between species, and expensive and troublesome in vivo test procedures. In this method, we explain how to model and characterize a realistic in vitro BBB model using human derived cells and perform a drug permeability test using this model.
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2020
The objective of the study was to produce three-dimensional and porous nanofiber reinforced hydrogel scaffolds that can mimic the hydrated composite structure of the cartilage extracellular matrix. In this regard, wet-electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofiber reinforced carboxymethyl chitosan-silk fibroin (PNFs/CMCht-SF) hydrogel composite scaffolds that were chemically cross-linked by poly(ethylene glycol) diglycidyl ether (PEGDE) were produced. To the best of our knowledge, this is the first study in cartilage regeneration where a three dimensional porous spongy composite scaffold was obtained by the dispersion of wet-electrospun nanofibers within a polymer matrix. All of the produced hydrogel composite scaffolds had an interconnected microporous structure with well-integrated PHBV nanofibers on the pore walls. The scaffold comprising an equal amount of PEGDE and polymer (PNFs/CMCht-SF1:PEGDE1) demonstrated comparable water content (91.4 ± 0.7%), tan δ (0.183 at 1 Hz) and compressive strength (457 ± 85 kPa) values to that of articular cartilage. Besides, based on the histological analysis, this hydrogel composite scaffold supported the chondrogenic differentiation of bone marrow mesenchymal stem cells. Consequently, this hydrogel composite scaffold presented a great promise for cartilage tissue regeneration.