Cell Viability Of Hydrogels Research Articles

Polyvinyl alcohol-silk fibroin composite stents: A comprehensive investigation into biocompatibility and mechanical performance

Bioresorbable stents (BRS) are manufactured using biodegradable materials. As an alternative to those commonly used in commercial stents, this study explored the development of BRS using polyvinyl alcohol (PVA) and silk fibroin (SF). PVA is a promising material for the fabrication of BRS due to its biocompatibility and mechanical attributes, closely resembling those of aortic vessels. However, its application presents challenges in terms of cell adhesion and proliferation. SF has been extensively studied for its potential to enhance cell adhesion and proliferation, making it a promising biomaterial in the field of medical devices. SF was introduced by dissolving it in a PVA solution or by coating the hydrogel surface with a layer of SF. Initial tests revealed that overnight incubation of fetal bovine serum significantly increased cell viability in hydrogels. Viability assays confirmed that SF substantially improved cell viability compared to PVA alone. The method was extended to fabricate SF-coated stents, which demonstrated robust cell proliferation and improved performance compared to electrospun polycaprolactone scaffolds. In addition, the SF-coated stents displayed an increase in compressive strength, demonstrating improved biocompatibility and mechanical performance. Dynamic mechanical analysis evaluated the positive impact of SF on stent properties at physiological temperatures. The study revealed that PVA-SF stents offer a compromise between biocompatibility, mechanical strength, and elastic recovery, positioning them as a valuable alternative for cardiovascular stent applications. The dual benefits of enhanced biocompatibility and improved mechanical performance make SF-coated stents promising candidates for bioresorbable stent design.  

Comparison of Silk Hydrogels Prepared via Different Methods.

Silk fibroin (SF) hydrogels have garnered extensive attention in biomedical materials, owing to their superior biological properties. However, the challenges facing the targeted silk fibroin hydrogels involve chemical agents and shortfalls in performance. In this study, the silk fibroin hydrogels were prepared in different ways: sonication induction, chemical crosslinking, photopolymerization, and enzyme-catalyzed crosslinking. The SF hydrogels derived from photopolymerization exhibited higher compressive properties, with 124 Kpa fracture compressive stress and breaks at about 46% compression. The chemical crosslinking and enzyme-catalyzed silk fibroin hydrogels showed superior toughness, yet sonication-induced hydrogels showed brittle performance resulting from an increase in silk II crystals. The chemical-crosslinked hydrogel demonstrated lower thermostability due to the weaker crosslinking degree. In vitro, all silk fibroin hydrogels supported the growth of human umbilical vein endothelial cells, as the cell viability of hydrogels without chemical agents was relatively higher. This study provides insights into the formation process of silk fibroin hydrogels and optimizes their design strategy for biomedical applications.

Engineering a 3D hydrogel system to study optic nerve head astrocyte morphology and behavior

In glaucoma, astrocytes within the optic nerve head (ONH) rearrange their actin cytoskeleton, while becoming reactive and upregulating intermediate filament glial fibrillary acidic protein (GFAP). Increased transforming growth factor beta 2 (TGF β2) levels have been implicated in glaucomatous ONH dysfunction. A key limitation of using conventional 2D culture to study ONH astrocyte behavior is the inability to faithfully replicate the in vivo ONH microenvironment. Here, we engineer a 3D ONH astrocyte hydrogel to better mimic in vivo mouse ONH astrocyte (MONHA) morphology, and test induction of MONHA reactivity using TGF β2. Primary MONHAs were isolated from C57BL/6J mice and cell purity confirmed. To engineer 3D cell-laden hydrogels, MONHAs were mixed with photoactive extracellular matrix components (collagen type I, hyaluronic acid) and crosslinked for 5 minutes using a photoinitiator (0.025% riboflavin) and UV light (405-500 nm, 10.3 mW/cm2). MONHA-encapsulated hydrogels were cultured for 3 weeks, and then treated with TGF β2 (2.5, 5.0 or 10 ng/ml) for 7 days to assess for reactivity. Following encapsulation, MONHAs retained high cell viability in hydrogels and continued to proliferate over 4 weeks as determined by live/dead staining and MTS assays. Sholl analysis demonstrated that MONHAs within hydrogels developed increasing process complexity with increasing process length over time. Cell processes connected with neighboring cells, coinciding with Connexin43 expression within astrocytic processes. Treatment with TGF β2 induced reactivity in MONHA-encapsulated hydrogels as determined by altered F-actin cytoskeletal morphology, increased GFAP expression, and elevated fibronectin and collagen IV deposition. Our data sets the stage for future use of this 3D biomimetic ONH astrocyte-encapsulated hydrogel to investigate astrocyte behavior in response to injury.

Preparation and Characterization of Plasma-Derived Fibrin Hydrogels Modified by Alginate di-Aldehyde.

Fibrin hydrogels are one of the most popular scaffolds used in tissue engineering due to their excellent biological properties. Special attention should be paid to the use of human plasma-derived fibrin hydrogels as a 3D scaffold in the production of autologous skin grafts, skeletal muscle regeneration and bone tissue repair. However, mechanical weakness and rapid degradation, which causes plasma-derived fibrin matrices to shrink significantly, prompted us to improve their stability. In our study, plasma-derived fibrin was chemically bonded to oxidized alginate (alginate di-aldehyde, ADA) at 10%, 20%, 50% and 80% oxidation, by Schiff base formation, to produce natural hydrogels for tissue engineering applications. First, gelling time studies showed that the degree of ADA oxidation inhibits fibrin polymerization, which we associate with fiber increment and decreased fiber density; moreover, the storage modulus increased when increasing the final volume of CaCl2 (1% w/v) from 80 µL to 200 µL per milliliter of hydrogel. The contraction was similar in matrices with and without human primary fibroblasts (hFBs). In addition, proliferation studies with encapsulated hFBs showed an increment in cell viability in hydrogels with ADA at 10% oxidation at days 1 and 3 with 80 µL of CaCl2; by increasing this compound (CaCl2), the proliferation does not significantly increase until day 7. In the presence of 10% alginate oxidation, the proliferation results are similar to the control, in contrast to the sample with 20% oxidation whose proliferation decreases. Finally, the viability studies showed that the hFB morphology was maintained regardless of the degree of oxidation used; however, the quantity of CaCl2 influences the spread of the hFBs.

SYNTHESIS, CHARACTERIZATION AND BIOCOMPATIBILITY OF PLANT-OIL BASED HYDROGELS

Biocompatible hydrogels are used in a variety of biomedical applications, including tissue scaffolds, drug delivery systems, lab/organ-on-a-chips, biosensors, cell-culture studies and contact lenses. The demand for novel and functional monomers to be used in hydrogel synthesis is increasing as the number of biomedical applications and need for biomaterials increase. The purpose of the study was to develop novel hydrogels from renewable materials. Acrylated methyl ricinoleate, a plant oil-based monomer, was used as the renewable material. The effects of acrylated methyl ricinoleate/N-isopropyl acrylamide molar ratio on hydrogel structural properties, thermal stability and in vitro cytotoxicity were studied. FTIR spectroscopy was used to characterize the structural properties of the hydrogels, while TGA was used to characterize the thermal properties. HEK293 and Cos-7 cell lines were used to test the cytotoxicity of the monomers and hydrogels. IC50 values for acrylated methyl ricinoleate and N-isopropyl acrylamide were found to be greater than 25 mg/mL. Cell viability of hydrogels containing 50% or more acrylated methyl ricinoleate was greater than 60%, while hydrogel biocompatibility decreased with decreasing molar ratio of acrylated methyl ricinoleate. Cells showed a minimum viability of 80% when incubated in hydrogel degradation products. An environmentally friendly synthesis method was developed and novel biocompatible hydrogels from renewable materials were produced for biomedical applications.

Fabrication and evaluation of chitosan/gelatin/PVA hydrogel incorporating honey for wound healing applications: An in vitro, in vivo study

In this study, physically cross-linked hydrogels were developed by freezing-thawing method while different concentrations of honey were included into the hydrogels for accelerated wound healing. The hydrogel was composed of chitosan, polyvinyl alcohol (PVA), and gelatin with the ratio of 2:1:1 (v/v), respectively. Further, the effect of honey concentrations on antibacterial properties, and cell behavior was investigated. In vivo studies, including wound healing mechanism using rat model and histological analysis of section tissue samples were performed. The results illustrated that the incorporation of honey in hydrogels increased the ultimate strain of hydrogels approximately two times, while reduced the ultimate tensile strength and elastic modulus of hydrogels. Moreover, the antibacterial activities of samples were increased by increasing the concentration of honey. Regarding MTT assay, as the concentration of honey increased, the cell viability of hydrogels was enhanced until an optimal amount of honey. Further, the integration of honey into the hydrogel matrix results in the maintenance of a well-structured layer of epidermis containing mature collagen and accelerates the rate of wound healing. The 3D Chitosan/PVA/Gelatin hydrogel containing honey with appropriate mechanical, antibacterial activity, and biocompatibility could be a promising approach for wound healing.

Beyond 2D: effects of photobiomodulation in 3D tissue-like systems.

.Significance: Currently, various scaffolds with immobilized cells are widely used in tissue engineering and regenerative medicine. However, the physiological activity and cell viability in such constructs might be impaired due to a lack of oxygen and nutrients. Photobiomodulation (PBM) is a promising method of preconditioning cells to increase their metabolic activity and to activate proliferation or differentiation.Aim: Investigation of the potential of PBM for stimulation of cell activities in hydrogels.Approach: Mesenchymal stromal cells (MSCs) isolated from human gingival mucosa were encapsulated in modified fibrin hydrogels with different thicknesses and concentrations. Constructs with cells were subjected to a single-time exposure to red (630 nm) and near-infrared (IR) (840 nm) low-intensity irradiation. After 3 days of cultivation, the viability and physiological activity of the cells were analyzed using confocal microscopy and a set of classical tests for cytotoxicity.Results: The cell viability in fibrin hydrogels depended both on the thickness of the hydrogels and the concentration of gel-forming proteins. The PBM was able to improve cell viability in hydrogels. The most pronounced effect was achieved with near-IR irradiation at the 840-nm wavelength.Conclusions: PBM using near-IR light can be applied for stimulation of MSCs metabolism and proliferation in hydrogel-based constructs with thicknesses up to 3 mm.