Nanofabricated collagen-inspired synthetic elastomers for primary rat hepatocyte culture.
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ABSTRACT:
SUBMITTER: Bettinger CJ
PROVIDER: S-EPMC2789736 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:AIM:To explore the methods of hepatocytes culture in a collagen gel mixture or between double layers of collagen sandwich configuration and to examine the functional and cytomorphological characteristics of cultured hepatocytes. METHODS:A two-step collagenase perfusion technique was used to isolate the hepatocytes from Wistar rats or newborn Chinese experimental piglets. The isolated hepatocytes were cultured in a collagen gel mixture or between double layers of collagen sandwich configuration respectively. The former was that rat hepatocytes were mixed with type I rat tail collagen solution till gelled, and the medium was added onto the gel. The latter was that swine hepatocytes were seeded on a plate precoated with collagen gel for 24 h, then another layer of collagen gel was overlaid, resulting in a sandwich configuration. The cytomorphological characteristics, albumin secretion, and LDH-release of the hepatocytes cultured in these two models were examined. RESULTS:Freshly isolated rat hepatocytes were successfully mixed and fixed in collagen gel, and cultured in the gel condition. During the culture period, the urea synthesized and secreted by rat hepatocytes was detected throughout the period. Likewise, newborn experimental piglet hepatocytes were successfully fixed between the double layers of collagen gel, forming a sandwich configuration. Within a week of culture, the albumin secreted by swine hepatocytes was detected by SDS/PAGE analysis. The typical cytomorphological characteristics of the hepatocytes cultured by the above two culture models were found under a phase-contrast microscope. There was little LDH-release during the culture period. CONCLUSION:Both collagen gel mixture and double layers of collagen sandwich configuration can provide cultural conditions much closer to in vivo environment, and are helpful for maintaining specific hepatic functions and cytomorphological characteristics. A collagen gel mixture culture may be more eligible for the study of bioartificial livers.
| S-EPMC4716912 | biostudies-literature
Project description:Materials often exhibit a trade-off between stiffness and extensibility; for example, strengthening elastomers by increasing their cross-link density leads to embrittlement and decreased toughness. Inspired by cuticles of marine mussel byssi, we circumvent this inherent trade-off by incorporating sacrificial, reversible iron-catechol cross-links into a dry, loosely cross-linked epoxy network. The iron-containing network exhibits two to three orders of magnitude increases in stiffness, tensile strength, and tensile toughness compared to its iron-free precursor while gaining recoverable hysteretic energy dissipation and maintaining its original extensibility. Compared to previous realizations of this chemistry in hydrogels, the dry nature of the network enables larger property enhancement owing to the cooperative effects of both the increased cross-link density given by the reversible iron-catecholate complexes and the chain-restricting ionomeric nanodomains that they form.
| S-EPMC5676464 | biostudies-other
Project description:Origami has become an optimal methodological choice for creating complex three-dimensional (3D) structures and soft robots. The simple and low-cost origami-inspired folding assembly provides a new method for developing 3D soft robots, which is ideal for future intelligent robotic systems. Here, we present a series of materials, structural designs, and fabrication methods for developing independent, electrically controlled origami 3D soft robots for walking and soft manipulators. The 3D soft robots are based on soft actuators, which are multilayer structures with a dielectric elastomer (DE) film as the deformation layer and a laser-cut PET film as the supporting flexible frame. The triangular and rectangular design of the soft actuators allows them to be easily assembled into crawling soft robots and pyramidal- and square-shaped 3D structures. The crawling robot exhibits very stable crawling behaviors and can carry loads while walking. Inspired by origami folding, the pyramidal and square-shaped 3D soft robots exhibit programmable out-of-plane deformations and easy switching between two-dimensional (2D) and 3D structures. The electrically controllable origami deformation allows the 3D soft robots to be used as soft manipulators for grasping and precisely locking 3D objects. This work proves that origami-inspired fold-based assembly of DE actuators is a good reference for the development of soft actuators and future intelligent multifunctional soft robots.
| S-EPMC8971403 | biostudies-literature
Project description:We have characterized the induction of acyl-CoA oxidase and cytochrome P450IVA1 RNAs in a primary hepatocyte culture system in vitro, using a sensitive and specific RNAse protection assay. Hepatocytes were cultured with a maximal inducing dose of the peroxisome proliferator clofibric acid (1 mM), or vehicle control, for 4 days, and the level of RNAs compared with the level in rats which had been treated with corn oil or clofibric acid (300 mg/kg) for 4 days. The level of acyl-CoA oxidase and P450IVA1 RNAs in 4-day-old control hepatocytes was less than 2% of that in control liver. However, the level of these RNAs in RNA from treated hepatocytes was 61% of that in liver RNA from treated rats. Hepatocytes were treated with the potent peroxisome proliferator methylclofenapate (100 microM), and the induction of RNAs determined at various times after exposure. P450IVA1 RNA was significantly induced 1 h after dosing, rising to 34-fold above control after 8 h, whereas acyl-CoA oxidase RNA was not significantly induced until 4 h, increasing to 5.2-fold above control after 8 h. A similar time course of induction was seen after treatment of hepatocytes with 100 microM-nafenopin, 100 microM-methylclofenapate, 1 mM-clofibric acid or 1 mM-mono(ethylhexyl) phthalate, suggesting that the differential time course of induction of P450IVA1 and acyl-CoA oxidase RNAs is not related to the esterification, structure or potency of the peroxisome proliferator, but is intrinsic to the process of peroxisome proliferation. Hepatocytes were treated with methylclofenapate in the presence and absence of cycloheximide. P450IVA1 RNA was significantly induced by methylclofenapate in the presence of cycloheximide, rising to 17-fold above control after 8 h. However, no induction of acyl-CoA oxidase RNA was detected in the presence of cycloheximide. Therefore we characterize the induction of acyl-CoA oxidase and P450IVA1 RNAs in primary hepatocyte culture in vitro as a faithful model of the induction response in rat liver, and suggest that induction of P450IVA1 RNA is a primary event in the process of peroxisome proliferation.
| S-EPMC1130627 | biostudies-other
Project description:The structural integrity of living plant cells heavily relies on the plant cell wall containing a nanofibrous cellulose skeleton. Hence, if synthetic plant cells consist of such a cell wall, they would allow for manipulation into more complex synthetic plant structures. Herein, we have overcome the fundamental difficulties associated with assembling lipid vesicles with cellulosic nanofibers (CNFs). We prepare plantosomes with an outer shell of CNF and pectin, and beneath this, a thin layer of lipids (oleic acid and phospholipids) that surrounds a water core. By exploiting the phase behavior of the lipids, regulated by pH and Mg2+ ions, we form vesicle-crowded interiors that change the outer dimension of the plantosomes, mimicking the expansion in real plant cells during, e.g., growth. The internal pressure enables growth of lipid tubules through the plantosome cell wall, which paves the way to the development of hierarchical plant structures and advanced synthetic plant cell mimics.
| S-EPMC7031234 | biostudies-literature
Project description:ObjectivesCorneal endothelial cell (CEC) isolation and harvest aim to produce engineered grafts to solve donor corneal tissue shortage. To yield high amounts of CEC maintaining morphological and molecular characteristics, several isolation and culture conditions are reported. Here, we combined direct explant culture, with three different coating conditions and a two-step media approach to compare confluence efficiency, morphology, and specific molecular markers expression.Data descriptionConfluence was reached after 2 weeks in the three coating conditions (Matrigel, collagen I, and in uncoated plates) using a two-step approach (proliferative medium without pituitary extract, followed by stabilizer basal medium). Na/K-ATPase and GPC4 markers were detected by immunocytochemistry while GPC4, CD200, and TJP1 by RT-PCR in the three CEC coating culture conditions. CEC in proliferative medium showed spindle morphology in the three conditions. Polygonal morphology was seen in CEC cultures using basal medium under uncoated and collagen I coated plates. CEC cultured in Matrigel-coated plates remained with spindle morphology in basal medium.
| S-EPMC5774048 | biostudies-literature
Project description:The present study was set up to investigate the effects of Trichostatin A (TSA), a prototypical epigenetic modifier, on the expression and activity of hepatic drug uptake transporters in primary cultured rat hepatocytes. To this end, the expression of the sinusoidal transporters sodium-dependent taurocholate cotransporting polypeptide (Ntcp) and organic anion transporting polypeptide 4 (Oatp4) was monitored by real-time quantitative reverse transcriptase polymerase chain reaction analysis and immunoblotting. The activity of the uptake transporters was analyzed using radiolabeled substrates and chemical inhibitors. Downregulation of the expression and activity of Oatp4 and Ntcp was observed as a function of the cultivation time and could not be counteracted by TSA. In conclusion, the epigenetic modifier TSA does not seem to exert a positive effect on the expression and activity of the investigated uptake transporters in primary rat hepatocyte cultures.
| S-EPMC4669911 | biostudies-literature
Project description:Elastomers are essential for stretchable electronics, which have become more and more important in bio-integrated devices. To ensure high compliance with the application environment, elastomers are expected to resist, and even self-repair, mechanical damage, while being friendly to the human body. Herein, inspired by peptidoglycan, we designed the first room-temperature autonomous self-healing biodegradable and biocompatible elastomers, poly(sebacoyl 1,6-hexamethylenedicarbamate diglyceride) (PSeHCD) elastomers. The unique structure including alternating ester-urethane moieties and bionic hybrid crosslinking endowed PSeHCD elastomers superior properties including ultrafast self-healing, tunable biomimetic mechanical properties, facile reprocessability, as well as good biocompatibility and biodegradability. The potential of the PSeHCD elastomers was demonstrated as a super-fast self-healing stretchable conductor (21 s) and motion sensor (2 min). This work provides a new design and synthetic principle of elastomers for applications in bio-integrated electronics.
| S-EPMC8288426 | biostudies-literature
Project description:The study was performed using primary rat hepatocyte in culture from 4 adult male Sprague-Dawley rats to investigate the changes in gene expression under low dose (4μM) and short exposure (3hrs) of cadmium chloride. By comparing the gene expression profiles of control and cadmium-treated cells, the most dramatic and significant changes were for those genes associated with transcriptional regulation, antioxidant response and control of protein integrity. Changes in other genes involved in cellular physiological responses such as inflammation, growth and apoptosis were also observed. Results were further confirmed by quantitative real time polymerase chain reaction (qRT-PCR). Experiment Overall Design: Primary hepatocytes from four rats were isolated using the collagenase-hyaluronidase perfusion and digestion method. The cells of greater than 85% viability were used in this study. The cells were plated at 90% confluency on culture dishes coated with collagen and maintained in Waymouth's medium containing BSA for 4hrs prior to an overnight incubation with BSA free Waymouth's medium. Control samples and cadmium-treated samples from individual rats were hybridized to RAE 230A arrays (n=4 and 8 microarrays); data were generated and analyzed.
2009-03-07 | E-GEOD-8013 | biostudies-arrayexpress
Project description:While study in the field of polymer mechanochemistry has yielded mechanophores that perform various chemical reactions in response to mechanical stimuli, there is not yet a triggering method compatible with biological systems. Applications such as using mechanoluminescence to generate localized photon flux in vivo for optogenetics would greatly benefit from such an approach. Here we introduce a method of triggering mechanophores by using high-intensity focused ultrasound (HIFU) as a remote energy source to drive the spatially and temporally resolved mechanical-to-chemical transduction of mechanoresponsive polymers. A HIFU setup capable of controlling the excitation pressure, spatial location, and duration of exposure is employed to activate mechanochemical reactions in a cross-linked elastomeric polymer in a noninvasive fashion. One reaction is the chromogenic isomerization of a naphthopyran mechanophore embedded in a polydimethylsiloxane (PDMS) network. Under HIFU irradiation evidence of the mechanochemical transduction is the observation of a reversible color change as expected for the isomerization. The elastomer exhibits this distinguishable color change at the focal spot, depending on ultrasonic exposure conditions. A second reaction is the demonstration that HIFU irradiation successfully triggers a luminescent dioxetane, resulting in localized generation of visible blue light at the focal spot. In contrast to conventional stimuli such as UV light, heat, and uniaxial compression/tension testing, HIFU irradiation provides spatiotemporal control of the mechanochemical activation through targeted but noninvasive ultrasonic energy deposition. Targeted, remote light generation is potentially useful in biomedical applications such as optogenetics where a light source is used to trigger a cellular response.
| S-EPMC6534979 | biostudies-literature