The abnormal levels of pH and oxygen (O-2) in the wound microenvironment impeded wound healing, and their regulation remains a challenge. Thus, a wound dressing with pH and O-2-regulating capacity is urgently desired....
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The abnormal levels of pH and oxygen (O-2) in the wound microenvironment impeded wound healing, and their regulation remains a challenge. Thus, a wound dressing with pH and O-2-regulating capacity is urgently desired. Here, we designed and prepared a fluorinated peptide hydrogel wound dressing to regulate the pH and O-2 microenvironment of the wound site. Fluorinated peptides with the (naphthalene-2-ly)-Gly-(5f)Phe-(5f)Phe-Tyr-Arg-Gly-Asp sequence (F-5-Pep) could self-assemble to a nanofiber network in a weak acidic buffer (pH = 6.0), which is similar to the pH of human skin. The F-5-Pep hydrogel can maintain pH levels at 6.0-7.3 for 24 h and continuously release O-2 for 4 h. The blood coagulation and hemostasis assay showed that the F-5-Pep hydrogel significantly accelerated blood clotting speed in vitro and rapidly controlled hemorrhage in a mouse liver hemorrhage model. In vitro cell migration assays and in vivo animal experiments confirmed that the F-5-Pep hydrogel can promote cell migration and wound healing. In summary, this work might provide an effective treatment strategy for wounds and develop advanced wound-healing materials.
oxygen levels in vivo are autonomously regulated by a supply-demand balance, which can be altered in disease states. However, the oxygen levels of in vitro cell culture systems, particularly microscale cell culture, a...
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oxygen levels in vivo are autonomously regulated by a supply-demand balance, which can be altered in disease states. However, the oxygen levels of in vitro cell culture systems, particularly microscale cell culture, are typically dominated by either supply or demand. Further, the oxygen microenvironment in these systems is rarely monitored or reported. Here, a method to establish and dynamically monitor autonomously regulated oxygen microenvironments (AROM) using an oil overlay in an open microscale cell culture system is presented. Using this method, the oxygen microenvironment is dynamically regulated via the supply-demand balance of the system. Numerical simulation and experimental validation of oxygen transport within multi-liquid-phase, microscale culture systems involving a variety of cell types, including mammalian, fungal, and bacterial cells are presented. Finally, AROM is applied to establish a coculture between cells with disparate oxygen demands-primary intestinal epithelial cells (oxygen consuming) and Bacteroides uniformis (an anaerobic species prevalent in the human gut).
Background Culturing neuronal cells in vitro , especially at smaller scales with reduced media volumes, has been challenging due to the limited proliferation of mature neurons and the inherent high sensitivity of neur...
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Background Culturing neuronal cells in vitro , especially at smaller scales with reduced media volumes, has been challenging due to the limited proliferation of mature neurons and the inherent high sensitivity of neuronal cells to environmental fluctuations. New method In this study, we report a neuronal cell culture method that leverages oil overlay and an autonomously regulated oxygen microenvironment (AROM), in which primary rat cortical cells and human neural progenitor cells (NPCs) were cultured in standard well plates with an oil overlay on top of the media layer. The oil overlay prevents evaporation and achieves in vivo -like oxygen concentrations without the use of glove boxes or hypoxic chambers. Results This oil overlay method achieved >95% yield of viable replicates after up to 30 days. Human NPCs cultured under the oil overlay for 15 days exhibited sustained viability without requiring media change. Additionally, oil overlays create a modulated oxygen microenvironment (i.e., AROM) that mimics in vivo conditions, capable of maintaining and restoring optimal oxygen concentrations after disturbances. Comparison with existing method In contrast, existing method (no-oil controls) resulted in <20% yield, low viability for human NPCs (11% versus 89% with oil overlay), and oxygen concentrations that returns to ambient levels (21% oxygen). Conclusion Overall, these results support the oil overlay method as a robust small-scale neuronal cell culture system, offering improved stability and higher yield. The results also underscore the critical role of the oxygen microenvironment in supporting neuronal cell viability, maintenance, and growth.
oxygen participates in numbers of cellular activities and behaviors in both normal and pathological tissues. In physiological microenvironment, oxygen tension is generally below 21 % and varies in different species, s...
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oxygen participates in numbers of cellular activities and behaviors in both normal and pathological tissues. In physiological microenvironment, oxygen tension is generally below 21 % and varies in different species, states and regions of organs. However, present studies of cellular behavior in vitro are performed in an ambient level, which is not conformity to the reality in vivo. In this study, a microfluidic device was developed to generate controllable oxygen tensions on a multiple-channel array chip for high-throughput drug screening. Controlling various concentrations of chemical reagents with confined flow rate, specific oxygen tensions can be established from 1.6 to 21 %, where the oxygen tension of each channel can be modulated in demand. When the concentrations of pyrogallol change from 100 to 700 mu g/mL with the flow rate of 5 mu L/min, oxygen tensions in cell chambers range from 12.5 to 3.87 %. Pyrogallol with the concentration of 0 mu g/mL is used as the control group to obtain 20.9 % oxygen condition. The developed microfluidic chip was used to investigate the cytotoxicity of TPZ and cisplatin, and the results demonstrate different manners of two oxygen-sensitive anti-tumor drugs in oxygen-dependent cytotoxic responses. Due to its character, the microfluidic device is believed to establish any desired and measurable oxygen tension distribution for pharmacology development, which is promising to improve efficiency and reduce tedious operation for pharmaceutical studies.
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