Electrochemical Modulation of Carbon Monoxide-Mediated Cell Signaling

Spatiotemporal Nitric Oxide Modulation via Electrochemical Platform to Profile Tumor Cell Response

Nitric oxide (NO) is a gaseous molecule intricately implicated in oncologic processes, encompassing the modulation of angiogenesis and instigating apoptosis. Investigation of the antitumor effects of NO is currently underway, necessitating a detailed understanding of its cellular-level reactions. Regulating the behavior of radical NO species has been a significant challenge, primarily due to its instability in aqueous environments by rapid O2-induced degradation. In this study, we devised an electrochemical platform to investigate the cellular responses to reactive gaseous molecules. Our designed platform precisely controlled the NO flux and diffusion rates of NO to tumor cells. COMSOL Multiphysics calculations based on diffusion and reaction kinetics were conducted to simulate the behavior of electrochemically generated NO. We discerned that the effective radius, NO flux, and electrolysis duration are pivotal factors governing cellular response by NO.

Fe(III)-Based Fluorescent Probe for High-Performance Recognition, Test Strip Analysis, and Cell Imaging of Carbon Monoxide

Fluorescence sensing and imaging techniques are being widely studied for detecting carbon monoxide (CO) in living organisms due to their speed, sensitivity, and ease of use to biological systems. Most fluorescent probes used for this purpose are based on heavy metal ions like Pd, with a few using elements like Ru, Rh, Ir, Os, Tb, and Eu. However, these metals can be expensive and toxic to cells. There is a need for more affordable and biologically safe fluorescent probes for CO detection. Drawing inspiration from the robust affinity exhibited by heme iron toward CO, in this work, a rhodamine derivative called RBF was developed for imaging CO in living cells by binding to Fe(III) and could be used for CO sensing. A Fe(III)-based fluorescent probe for CO imaging in living cells offers advantages of cost effectiveness, low toxicity, and ease of use. The fluorescence detection using the RBF-Fe system showed a direct correlation with increasing levels of CORM-3 (LOD = 146 nM) or the exposure time of CO gas, displaying reduced fluorescence. A CO test paper based on RBF-Fe was created for simple on-site CO detection, where fluorescence would diminish in response to CO exposure, allowing rapid (2 min) visual identification. Imaging of CO in living cells was successfully conducted using the probe system, showing a decrease in fluorescence intensity as CORM-3 concentrations increased, indicating its effectiveness in monitoring CO levels accurately within living cells.

Durable immunomodulatory hierarchical patch for rotator cuff repairing

Degradable rotator cuff patches, followed over five years, have been observed to exhibit high re-tear rates exceeding 50%, which is attributed to the inability of degradable polymers alone to restore the post-rotator cuff tear (RCT) inflammatory niche. Herein, poly(ester-ferulic acid-urethane)urea (PEFUU) was developed, featuring prolonged anti-inflammatory functionality, achieved by the integration of ferulic acid (FA) into the polyurethane repeating units. PEFUU stably releases FA in vitro, reversing the inflammatory niche produced by M1 macrophages and restoring the directed differentiation of stem cells. Utilizing PEFUU, hierarchical composite nanofiber patch (HCNP) was fabricated, simulating the natural microstructure of the tendon-to-bone interface with an aligned-random alignment. The incorporation of enzymatic hydrolysate derived from decellularized Wharton jelly tissue into the random layer could further enhance cartilage regeneration at the tendon-to-bone interface. Via rat RCT repairing model, HCNP possessing prolonged anti-inflammatory properties uniquely facilitated physiological healing at the tendon-to-bone interface's microstructure. The alignment of fibers was restored, and histologically, the characteristic tripartite distribution of collagen I - collagen II - collagen I was achieved. This study offers a universal approach to the functionalization of degradable polymers and provides a foundational reference for their future applications in promoting the in vivo regeneration of musculoskeletal tissues.

Application of magnetism in tissue regeneration: recent progress and future prospects

Tissue regeneration is a hot topic in the field of biomedical research in this century. Material composition, surface topology, light, ultrasonic, electric field and magnetic fields (MFs) all have important effects on the regeneration process. Among them, MFs can provide nearly non-invasive signal transmission within biological tissues, and magnetic materials can convert MFs into a series of signals related to biological processes, such as mechanical force, magnetic heat, drug release, etc. By adjusting the MFs and magnetic materials, desired cellular or molecular-level responses can be achieved to promote better tissue regeneration. This review summarizes the definition, classification and latest progress of MFs and magnetic materials in tissue engineering. It also explores the differences and potential applications of MFs in different tissue cells, aiming to connect the applications of magnetism in various subfields of tissue engineering and provide new insights for the use of magnetism in tissue regeneration.

Membrane-Bound Redox Enzyme Cytochrome bd-I Promotes Carbon Monoxide-Resistant Escherichia coli Growth and Respiration

The terminal oxidases of bacterial aerobic respiratory chains are redox-active electrogenic enzymes that catalyze the four-electron reduction of O2 to 2H2O taking out electrons from quinol or cytochrome c. Living bacteria often deal with carbon monoxide (CO) which can act as both a signaling molecule and a poison. Bacterial terminal oxidases contain hemes; therefore, they are potential targets for CO. However, our knowledge of this issue is limited and contradictory. Here, we investigated the effect of CO on the cell growth and aerobic respiration of three different Escherichia coli mutants, each expressing only one terminal quinol oxidase: cytochrome bd-I, cytochrome bd-II, or cytochrome bo3. We found that following the addition of CO to bd-I-only cells, a minimal effect on growth was observed, whereas the growth of both bd-II-only and bo3-only strains was severely impaired. Consistently, the degree of resistance of aerobic respiration of bd-I-only cells to CO is high, as opposed to high CO sensitivity displayed by bd-II-only and bo3-only cells consuming O2. Such a difference between the oxidases in sensitivity to CO was also observed with isolated membranes of the mutants. Accordingly, O2 consumption of wild-type cells showed relatively low CO sensitivity under conditions favoring the expression of a bd-type oxidase.

New Opportunities of Electrochemistry for Monitoring, Modulating, and Mimicking the Brain Signals

In vivo electrochemistry is a powerful key for unlocking the chemical consequences in neural networks of the brain. The past half-century has witnessed the technology revolutionization in this field along with innovations in electrochemical concepts, principles, methods, and devices. Present applications of electrochemical approaches have extended from measuring neurochemical concentrations to modulating and mimicking brain signals. In this Perspective, newly reported strategies for tackling long-standing challenges of in vivo electrochemical brain monitoring (i.e., basal level measurement, electroactivity dependence, in vivo stability, neuron compatibility, multiplexity, and implantable device fabrication) are highlighted. Moreover, recent progress on neuromodulation tools and neuromorphic devices in electrochemical frameworks is introduced. A glimpse of future opportunities for electrochemistry in brain research is offered at last.

Stretchable One-Dimensional Conductors for Wearable Applications

Continuous, one-dimensional (1D) stretchable conductors have attracted significant attention for the development of wearables and soft-matter electronics. Through the use of advanced spinning, printing, and textile technologies, 1D stretchable conductors in the forms of fibers, wires, and yarns can be designed and engineered to meet the demanding requirements for different wearable applications. Several crucial parameters, such as microarchitecture, conductivity, stretchability, and scalability, play essential roles in designing and developing wearable devices and intelligent textiles. Methodologies and fabrication processes have successfully realized 1D conductors that are highly conductive, strong, lightweight, stretchable, and conformable and can be readily integrated with common fabrics and soft matter. This review summarizes the latest advances in continuous, 1D stretchable conductors and emphasizes recent developments in materials, methodologies, fabrication processes, and strategies geared toward applications in electrical interconnects, mechanical sensors, actuators, and heaters. This review classifies 1D conductors into three categories on the basis of their electrical responses: (1) rigid 1D conductors, (2) piezoresistive 1D conductors, and (3) resistance-stable 1D conductors. This review also evaluates the present challenges in these areas and presents perspectives for improving the performance of stretchable 1D conductors for wearable textile and flexible electronic applications.

Modulating cell signalling in vivo with magnetic nanotransducers

Weak magnetic fields offer nearly lossless transmission of signals within biological tissue. Magnetic nanomaterials are capable of transducing magnetic fields into a range of biologically relevant signals in vitro and in vivo. These nanotransducers have recently enabled magnetic control of cellular processes, from neuronal firing and gene expression to programmed apoptosis. Effective implementation of magnetically controlled cellular signalling relies on careful tailoring of magnetic nanotransducers and magnetic fields to the responses of the intended molecular targets. This primer discusses the versatility of magnetic modulation modalities and offers practical guidelines for selection of appropriate materials and field parameters, with a particular focus on applications in neuroscience. With recent developments in magnetic instrumentation and nanoparticle chemistries, including those that are commercially available, magnetic approaches promise to empower research aimed at connecting molecular and cellular signalling to physiology and behaviour in untethered moving subjects.

Carbon Monoxide Signaling: Examining Its Engagement with Various Molecular Targets in the Context of Binding Affinity, Concentration, and Biologic Response

Carbon monoxide (CO) has been firmly established as an endogenous signaling molecule with a variety of pathophysiological and pharmacological functions, including immunomodulation, organ protection, and circadian clock regulation, among many others. In terms of its molecular mechanism(s) of action, CO is known to bind to a large number of hemoproteins with at least 25 identified targets, including hemoglobin, myoglobin, neuroglobin, cytochrome c oxidase, cytochrome P450, soluble guanylyl cyclase, myeloperoxidase, and some ion channels with dissociation constant values spanning the range of sub-nM to high μM. Although CO's binding affinity with a large number of targets has been extensively studied and firmly established, there is a pressing need to incorporate such binding information into the analysis of CO's biologic response in the context of affinity and dosage. Especially important is to understand the reservoir role of hemoglobin in CO storage, transport, distribution, and transfer. We critically review the literature and inject a sense of quantitative assessment into our analyses of the various relationships among binding affinity, CO concentration, target occupancy level, and anticipated pharmacological actions. We hope that this review presents a picture of the overall landscape of CO's engagement with various targets, stimulates additional research, and helps to move the CO field in the direction of examining individual targets in the context of all of the targets and the concentration of available CO. We believe that such work will help the further understanding of the relationship of CO concentration and its pathophysiological functions and the eventual development of CO-based therapeutics. SIGNIFICANCE STATEMENT: The further development of carbon monoxide (CO) as a therapeutic agent will significantly rely on the understanding of CO's engagement with therapeutically relevant targets of varying affinity. This review critically examines the literature by quantitatively analyzing the intricate relationships among targets, target affinity for CO, CO level, and the affinity state of carboxyhemoglobin and provide a holistic approach to examining the molecular mechanism(s) of action for CO.

The Advancement of Gas-Generating Nanoplatforms in Biomedical Fields: Current Frontiers and Future Perspectives

Diverse gases (NO, CO, H₂ S, H₂ , etc.) have been widely applied in the medical intervention of various diseases, including cancer, cardiovascular disease, ischemia-reperfusion injury, bacterial infection, etc., attributing to their inherent biomedical activities. Although many gases have many biomedical activities, their clinical use is still limited due to the rapid and free diffusion behavior of these gases molecules, which may cause potential side effects and/or ineffective treatment. Gas-generating nanoplatforms (GGNs) are effective strategies to address the aforementioned challenges of gas therapy by preventing gas production or release at nonspecific sites, enhancing GGNs accumulation at targeted sites, and controlling gas release in response to exogenous (UV, NIR, US, etc.) or endogenous (H₂ O₂ , GSH, pH, etc.) stimuli at the lesion site, further maintaining gas concentration within the effective range and achieving the purpose of disease treatment. This review comprehensively summarizes the advancements of "state-of-the-art" GGNs in the recent three years, with emphasis on the composition, structure, preparation process, and gas release mechanism of the nanocarriers. Furthermore, the therapeutic effects and limitations of GGNs in preclinical studies using cell/animal models are discussed. Overall, this review enlightens the further development of this field and promotes the clinical transformation of gas therapy.