Oxidation of Reduced Graphene Oxide via Cellular Redox Signaling Modulates Actin-Mediated Neurotransmission

TRPA1 nanovesicle-conjugated receptonics for rapid biocide screening

Although biocides are important materials in modern society and help protect human health and the environment, increasing exposure to combined biocides can cause severe side effects in the human body, such as lung fibrosis. In this study, we developed a receptonics system to screen for biocides in combined household chemical products based on biocides. The system contains transient receptor potential ankyrin 1 (TRPA1) nanovesicles (NVs) to sense biocides based on pain receptors and a side-gated field-effect transistor (SGFET) using a single-layer graphene (SLG) micropattern channel. The binding affinities between the TRPA1 receptor and the various biocides were estimated by performing biosimulation and using a calcium ion (Ca2+) assay, and the sensitivity of the system was compared with that of TRPA1 NV receptonics systems. Based on the results of the TRPA1 NV receptonics system, the antagonistic and potentiation effects of combined biocides and household chemical products depended on the concentration. Finally, the TRPA1 NV receptonics system was applied to screen for biocides in real products, and its performance was successful. Based on these results, the TRPA1 NV receptonics system can be utilized to perform risk evaluations and identify biocides in a simple and rapid manner.

Synergistic role of MoS2 in gelation-induced fabrication of graphene oxide films

Supporting materials for electrocatalysts must exhibit relative chemical inertness to facilitate unimpeded movement of gas, and demonstrate electrical conductivity to promote efficient electron transfer to the catalyst. Conventional catalyst electrodes, such as glassy carbon, carbon cloths, or Ni foam, are commonly employed. However, the challenge lies in the limited stability observed during testing due to the relatively weak adhesion between the catalyst and the electrode. Addressing this limitation is crucial for advancing the stability and performance of catalyst-electrode systems in various applications. Here, we suggest a novel fabrication method for a freestanding conducting film, accomplished through gelation, incorporating 1T-MoS2 and graphene oxide. 1T-MoS2 nanosheets play a crucial role in promoting the reduction of graphene oxide (GO) on the Zn foil. This contribution leads to accelerated film formation and enhanced electrical conductivity in the film. The synergistic effect also enhances the film's stability as catalyst supports. This study provides insights into the effective utilization of MoS2 and graphene oxide in the creating of advanced catalyst support systems with potential applications in diverse catalytic reaction.

Preparation of PDA-GO/CS composite scaffold and its effects on the biological properties of human dental pulp stem cells

Reduced graphene oxide (rGO) is an graphene oxide (GO) derivative of graphene, which has a large specific surface area and exhibited satisfactory physicochemical characteristics. In this experiment, GO was reduced by PDA to generate PDA-GO complex, and then PDA-GO was combined with Chitosan (CS) to synthesize PDA-GO/CS composite scaffold. PDA-GO was added to CS to improve the degradation rate of CS, and it was hoped that PDA-GO/CS composite scaffolds could be used in bone tissue engineering. Physicochemical and antimicrobial properties of the different composite scaffolds were examined to find the optimal mass fraction. Besides, we examined the scaffold's biocompatibility by Phalloidin staining and Live and Dead fluorescent staining.Finally, we applied ALP staining, RT-qPCR, and Alizarin red S staining to detect the effect of PDA-GO/CS on the osteogenic differentiation of human dental pulp stem cells (hDPSCs). The results showed that PDA-GO composite was successfully prepared and PDA-GO/CS composite scaffold was synthesized by combining PDA-GO with CS. Among them, 0.3%PDA-GO/CS scaffolds improves the antibacterial activity and hydrophilicity of CS, while reducing the degradation rate. In vitro, PDA-GO/CS has superior biocompatibility and enhances the early proliferation, migration and osteogenic differentiation of hDPSCs. In conclusion, PDA-GO/CS is a new scaffold materialsuitable for cell culture and has promising application prospect as scaffold for bone tissue engineering.

Loss of synaptic ribbons is an early cause in ROS-induced acquired sensorineural hearing loss

Considerable evidence of reactive oxygen species (ROS) involvement in cochlear hair cell (HC) loss, leading to acquired sensorineural hearing loss (SNHL), were reported. Cochlear synaptopathy between HCs and spiral ganglion neurons has been gathering attention as a cochlear HC loss precursor not detectable by normal auditory evaluation. However, the molecular mechanisms linking ROS with HC loss, as well as the relationship between ROS and cochlear synaptopathy have not been elucidated. Here, we examined these linkages using NOX4-TG mice, which constitutively produce ROS without stimulation. mRNA levels of Piccolo 1, a major component of the synaptic ribbon (a specialized structure surrounded by synaptic vesicles in HCs), were decreased in postnatal day 6 NOX4-TG mice cochleae compared to those in WT mice; they were also decreased by noise exposure in 2-week-old WT cochleae. As noise exposure induces ROS production, this suggests that the synaptic ribbon is a target of ROS. The level of CtBP2, another synaptic ribbon component, was significantly lower in NOX4-TG cochleae of 1-month-old and 4-month-old mice compared to that in WT mice, although no significant differences were noted at 1.5- and 2-months. The decrease in CtBP2 plateaued in 4-month-old NOX4-TG, while it gradually decreased from 1 to 6 months in WT mice. Furthermore, CtBP2 level in 2-month-old NOX4-TG mice decreased significantly after exposure to cisplatin and noise compared to that in WT mice. These findings suggest that ROS lead to developmental delays and early degeneration of synaptic ribbons, which could be potential targets for novel therapeutics for ROS-induced SNHL.

Dimensional effect of graphene nanostructures on cytoskeleton-coupled anti-tumor metastasis

Interactions between inorganic materials and living systems can be strongly influenced by the dimensional property of the materials, which can in turn impact biological activities. Although the role of biomaterials at the molecular and cellular scales has been studied, research investigating the effects of biomaterials across multiple dimensional scales is relatively scarce. Herein, comparing the effectiveness of two-dimensional graphene oxide nanosheets (GOs) and three-dimensional graphene oxide quantum dots (GOQDs) (though not zero-dimensional because of their significant surface area) in cancer therapies, we have discovered that GOs, with the same mass concentration, exhibit stronger anti-cancer and anti-tumor metastasis properties than GOQDs. Our research, which employed liquid-phase atomic force microscopy, revealed that lower-dimensional GOs create a more extensive nano-bio interface that impedes actin protein polymerization into the cytoskeleton, leading to the prevention of tumor metastasis. These results help to better understand the underlying mechanisms and offer a dimensional perspective on the potential of optimizing the properties of graphene-based materials for clinical applications, e.g., cancer therapy.

Insights into the toxicological effects of nanomaterials on atherosclerosis: mechanisms involved and influence factors

Atherosclerosis is one of the most common types of cardiovascular disease and is driven by lipid accumulation and chronic inflammation in the arteries, which leads to stenosis and thrombosis. Researchers have been working to design multifunctional nanomedicines with the ability to target, diagnose, and treat atherosclerosis, but recent studies have also identified that nanomaterials can cause atherosclerosis. Therefore, this review aims to outline the molecular mechanisms and physicochemical properties of nanomaterials that promote atherosclerosis. By analyzing the toxicological effects of nanomaterials on cells involved in the pathogenesis of atherosclerosis such as vascular endothelial cells, vascular smooth muscle cells and immune cells, we aim to provide new perspectives for the prevention and treatment of atherosclerosis, and raise awareness of nanotoxicology to advance the clinical translation and sustainable development of nanomaterials.

Rational synthesis of carbon dots with phosphate ester group for direct mapping of endogenous alkaline phosphatase and polarity monitoring in living cells

Carbon dots (CDs) have been extensively employed in biomolecule imaging. However, the imaging of biological enzymes with CDs has not been reported, which greatly limits their application in biological imaging. Herein, for the first time, a new type of fluorescent CDs is elaborately designed to realize the direct mapping of alkaline phosphatase (ALP) in cells. The obtained phosphorus and nitrogen co-doped CDs (P, N-CDs) generate specific structures including xanthene oxide and phosphate ester, thereby enabling P, N-CDs to be exclusively cleaved by ALP without auxiliary media. The fluorescence intensity of P, N-CDs can be specifically turned on in the presence of ALP, making them powerful probes for sensitive sensing of ALP activity with a detection limit of 1.27 U·L^-1. Meanwhile, P, N-CDs possessing electron deficiency structure fulfill sensitive responding to polarity variations. The excellent photo-bleaching resistance and biocompatibility of the P, N-CDs are taken for directly mapping the intracellular endogenous ALP via turned-on fluorescence imaging, as well as real-time monitoring the polarity fluctuation in cells through ratiometric fluorescence imaging. The present work offers a new way to design and synthesize functional CDs for direct imaging of intracellular enzymes.

Computational Biomaterials: Computational Simulations for Biomedicine

With the flourishing development of material simulation methods (quantum chemistry methods, molecular dynamics, Monte Carlo, phase field, etc.), extensive adoption of computing technologies (high-throughput, artificial intelligence, machine learning, etc.), and the invention of high-performance computing equipment, computational simulation tools have sparked the fundamental mechanism-level explorations to predict the diverse physicochemical properties and biological effects of biomaterials and investigate their enormous application potential for disease prevention, diagnostics, and therapeutics. Herein, the term "computational biomaterials" is proposed and the computational methods currently used to explore the inherent properties of biomaterials, such as optical, magnetic, electronic, and acoustic properties, and the elucidation of corresponding biological behaviors/effects in the biomedical field are summarized/discussed. The theoretical calculation of the physiochemical properties/biological performance of biomaterials applied in disease diagnosis, drug delivery, disease therapeutics, and specific paradigms such as biomimetic biomaterials is discussed. Additionally, the biosafety evaluation applications of theoretical simulations of biomaterials are presented. Finally, the challenges and future prospects of such computational simulations for biomaterials development are clarified. It is anticipated that these simulations would offer various methodologies for facilitating the development and future clinical translations/utilization of versatile biomaterials.

GLX351322, a Novel NADPH Oxidase 4 Inhibitor, Attenuates TMJ Osteoarthritis by Inhibiting the ROS/MAPK/NF-κB Signaling Pathways

As a degenerative disease in joints, temporomandibular joint osteoarthritis (TMJOA) is characterized by progressive cartilage degradation, subchondral bone remodeling, and chronic synovitis, severely undermining functions and quality of life in patients. NADPH oxidase 4 (NOX4) contributes to reactive oxygen species (ROS) production and inflammatory pathway activation in osteoarthritis, which has attracted increasing attention in research in recent years. GLX351322 (GLX), a novel NOX4 inhibitor, exerts a protective effect on chondrocytes. However, whether it has a therapeutic effect on ROS production and inflammatory responses in synovial macrophages remains to be evaluated. In this study, we examined the effect of GLX on LPS-induced ROS production and inflammatory responses in vitro and on complete Freund's adjuvant (CFA)-induced TMJ inflammation in vivo. We found that GLX could depress LPS-induced intracellular ROS production and inflammatory response without cytotoxicity by inhibiting the ROS/MAPK/NF-κB signaling pathways. In line with in vitro observations, GLX markedly attenuated the synovial inflammatory reaction in the TMJ, thus protecting the condylar structure from severe damage. Taken together, our results suggest that GLX intervention or NOX4 inhibition is a promising curative strategy for TMJOA and other inflammatory diseases.

How Nanoparticles Open the Paracellular Route of Biological Barriers: Mechanisms, Applications, and Prospects

Biological barriers are essential physiological protective systems and obstacles to drug delivery. Nanoparticles (NPs) can access the paracellular route of biological barriers, either causing adverse health impacts on humans or producing therapeutic opportunities. This Review introduces the structural and functional influences of NPs on the key components that govern the paracellular route, mainly tight junctions, adherens junctions, and cytoskeletons. Furthermore, we evaluate their interaction mechanisms and address the influencing factors that determine the ability of NPs to open the paracellular route, which provides a better knowledge of how NPs can open the paracellular route in a safer and more controllable way. Finally, we summarize limitations in the research models and methodologies of the existing research in the field and provide future research direction. This Review demonstrates the in-depth causes for the reversible opening or destruction of the integrity of barriers generated by NPs; more importantly, it contributes insights into the design of NP-based medications to boost paracellular drug delivery efficiency.

Precise Design Strategies of Nanotechnologies for Controlled Drug Delivery

Rapid advances in nanotechnologies are driving the revolution in controlled drug delivery. However, heterogeneous barriers, such as blood circulation and cellular barriers, prevent the drug from reaching the cellular target in complex physiologic environments. In this review, we discuss the precise design of nanotechnologies to enhance the efficacy, quality, and durability of drug delivery. For drug delivery in vivo, drugs loaded in nanoplatforms target particular sites in a spatial- and temporal-dependent manner. Advances in stimuli-responsive nanoparticles and carbon-based drug delivery platforms are summarized. For transdermal drug delivery systems, specific strategies including microneedles and hydrogel lead to a sustained release efficacy. Moreover, we highlight the current limitations of clinical translation and an incentive for the future development of nanotechnology-based drug delivery.

Is Graphene Shortening the Path toward Spinal Cord Regeneration?

Along with the development of the next generation of biomedical platforms, the inclusion of graphene-based materials (GBMs) into therapeutics for spinal cord injury (SCI) has potential to nourish topmost neuroprotective and neuroregenerative strategies for enhancing neural structural and physiological recovery. In the context of SCI, contemplated as one of the most convoluted challenges of modern medicine, this review first provides an overview of its characteristics and pathophysiological features. Then, the most relevant ongoing clinical trials targeting SCI, including pharmaceutical, robotics/neuromodulation, and scaffolding approaches, are introduced and discussed in sequence with the most important insights brought by GBMs into each particular topic. The current role of these nanomaterials on restoring the spinal cord microenvironment after injury is critically contextualized, while proposing future concepts and desirable outputs for graphene-based technologies aiming to reach clinical significance for SCI.

A sensitive ratiometric biosensor for determination cardiac troponin I of myocardial infarction markers based on N, Zn-GQDs

A sensitive unlabeled ratiometric biosensor was developed to the detection of cardiac troponin I (cTnI). This biosensor was established by using the glassy carbon electrode coated with graphene oxide to form a platform bonded with N, Zn co-doped graphene quantum dots (N, Zn-GQDs). The N, Zn-GQDs was successfully prepared as the raw materials of graphite powder and characterized. Antibodies of cTnI were bonded to the surface of N, Zn-GQDs as the nanoprobe by amide bonds. The signals of electrochemiluminescence (ECL) and differential pulse voltammetry (DPV) were exposed to decrease in the presence of cTnI, which caused the signal substance to move farther away from the electrode. It was found that the immune complex layer attenuated the intensity of ECL and DPV which could be used as the good overall signal for determining concentration of cTnI. The ratiometric biosensor had a good response to cTnI with the detection limit is 4.59 pg L^-1 in the concentration range of 10-10⁶ pg L^-1. The developed method was evaluated for the detection of cTnI in human serum, and the obtained results were consistent compared to the reference values obtained by hospital standard enzyme linked immunoassay (ELISA) with 9.09%-11.1% of RSD. Our findings suggested that this ratiometric biosensor could be used to the detection of cTnI in human serum with lower cost and higher sensitivity, it also might be better potential application prospect based on N, Zn-GQDs to detect other biomarkers.

Nano-graphene oxide depresses neurotransmission by blocking retrograde transport of mitochondria

The application of graphene-family nanomaterials (GFNs) in neuromedicine has recently gained increased attention, but the associated exposure risk for synaptic function and the underlying mechanism remains obscure. The results of this study utilizing nanosized graphene oxide (nGO) suggest that they exert depressive effects on neurotransmission, mainly due to energy deficiency at synaptic contacts. Mitophagy is activated but fails to renew mitochondria and maintain mitochondrial-mediated energy metabolism because of blockage of autophagosome transport through the microtubule system from the axonal terminal to the soma. Further investigation of the underlying mechanism indicates that nGO increases the level of microtubule detyrosination, which restrains loading of the dynactin-dynein motor complex onto microtubules and subsequently inhibits the efficacy of the retrograde transport route. Thus, our study reveals the underlying mechanism by which nGO depresses neurotransmission, and contributes to our understanding of the neurobiological effects of GFNs.

Nanomedicine and graphene-based materials: advanced technologies for potential treatments of diseases in the developing nervous system

The interest in graphene-based nanomaterials (GBNs) application in nanomedicine, in particular in neurology, steadily increased in the last decades. GBNs peculiar physical-chemical properties allow the design of innovative therapeutic tools able to manipulate biological structures with subcellular resolution. In this review, we report GBNs applications to the central nervous system (CNS) when these nanomaterials are engineered as potential therapeutics to treat brain pathologies, with a focus on those of the pediatric age. We revise the state-of-the art studies addressing the impact of GBNs in the CNS, showing that the design of GBNs with different dimensions and chemical compositions or the use of specific administration routes and doses can limit unwanted side effects, exploiting GBNs efficacy in therapeutic approaches. These features favor the development of GBNs-based multifunctional devices that may find applications in the field of precision medicine for the treatment of disorders in the developing CNS. In this framework, we address the suitability of GBNs to become successful therapeutic tools, such as drug nano-delivery vectors when being chemically decorated with pharmaceutical agents and/or other molecules to obtain a high specific targeting of the diseased area and to achieve a controlled release of active molecules. IMPACT: The translational potential of graphene-based nanomaterials (GBNs) can be used for the design of novel therapeutic approaches to treat pathologies affecting the brain with a focus on the pediatric age. GBNs can be chemically decorated with pharmaceutical agents and molecules to obtain a highly specific targeting of the diseased site and a controlled drug release. The type of GBNs, the selected functionalization, the dose, and the way of administration are factors that should be considered to potentiate the therapeutic efficacy of GBNs, limiting possible side effects. GBNs-based multifunctional devices might find applications in the precision medicine and theranostics fields.

GO-based antibacterial composites: Application and design strategies

Graphene oxide (GO), for its unique structure with high biocompatibility and designability, is widely used in the antibacterial field. Various strategies have been designed to fabricate GO-based composites with antibacterial properties. This review summarized these strategies, divided them into three types and interpreted their antibacterial mechanisms: (i) "GO*/non-GO" type in which GO acts as the single antibacterial core, (ii) "GO*/non-GO*" type in which GO and non-GO components function synergistically as dual antibacterial cores, (iii) "GO/non-GO*" type in which non-GO acts as the single antibacterial core, while GO component plays a supportive, not a dominant role in antibiosis. Besides, the fields suiting their applications and factors influencing their antibacterial properties were analyzed. Finally, the limitations and prospects in the current researches were discussed. In summary, GO-based composites have revolutionized antibacterial strategies. This review may serve as a reference to inspire further research on GO-based antibacterial composites.

Tuning the Reduction of Graphene Oxide Nanoflakes Differently Affects Neuronal Networks in the Zebrafish

The increasing engineering of biomedical devices and the design of drug-delivery platforms enriched by graphene-based components demand careful investigations of the impact of graphene-related materials (GRMs) on the nervous system. In addition, the enhanced diffusion of GRM-based products and technologies that might favor the dispersion in the environment of GRMs nanoparticles urgently requires the potential neurotoxicity of these compounds to be addressed. One of the challenges in providing definite evidence supporting the harmful or safe use of GRMs is addressing the variety of this family of materials, with GRMs differing for size and chemistry. Such a diversity impairs reaching a unique and predictive picture of the effects of GRMs on the nervous system. Here, by exploiting the thermal reduction of graphene oxide nanoflakes (GO) to generate materials with different oxygen/carbon ratios, we used a high-throughput analysis of early-stage zebrafish locomotor behavior to investigate if modifications of a specific GRM chemical property influenced how these nanomaterials affect vertebrate sensory-motor neurophysiology-exposing zebrafish to GO downregulated their swimming performance. Conversely, reduced GO (rGO) treatments boosted locomotor activity. We concluded that the tuning of single GRM chemical properties is sufficient to produce differential effects on nervous system physiology, likely interfering with different signaling pathways.

Graphene oxide disrupted mitochondrial homeostasis through inducing intracellular redox deviation and autophagy-lysosomal network dysfunction in SH-SY5Y cells

Graphene oxide (GO) nanomaterials have significant advantages for drug delivery and electrode materials in neural science, however, their exposure risks to the central nervous system (CNS) and toxicity concerns are also increased. The current studies of GO-induced neurotoxicity remain still ambiguous, let alone the mechanism of how complicated GO chemistry affects its biological behavior with neural cells. In this study, we characterized the commercially available GO in detail and investigated its biological adverse effects using cultured SH-SY5Y cells. We found that ultrasonic processing in medium changed the oxidation status and surface reactivity on the planar surface of GO due to its hydration activity, causing lipid peroxidation and cell membrane damage. Subsequently, ROS-disrupted mitochondrial homeostasis, resulting from the activation of NOX2 signaling, was observed following GO internalization. The autophagy-lysosomal network was initiated as a defensive reaction to obliterate oxidative damaged mitochondria and foreign nanomaterials, which was ineffective due to reduced lysosomal degradation capacity. These sequential cellular responses exacerbated mitochondrial stress, leading to apoptotic cell death. These data highlight the importance of the structure-related activity of GO on its biological properties and provide an in-depth understanding of how GO-derived cellular redox signaling induces mitochondrion-related cascades that modulate cell functionality and survival.

Understanding the interactions between inorganic-based nanomaterials and biological membranes

The interactions between inorganic-based nanomaterials (NMs) and biological membranes are among the most important phenomena for developing NM-based therapeutics and resolving nanotoxicology. Herein, we introduce the structural and functional effects of inorganic-based NMs on biological membranes, mainly the plasma membrane and the endomembrane system, with an emphasis on the interface, which involves highly complex networks between NMs and biomolecules (such as membrane proteins and lipids). Significant efforts have been devoted to categorizing and analyzing the interaction mechanisms in terms of the physicochemical characteristics and biological effects of NMs, which can directly or indirectly influence the effects of NMs on membranes. Importantly, we summarize that the biological membranes act as platforms and thereby mediate NMs-immune system contacts. In this overview, the existing challenges and potential applications in the areas are addressed. A strong understanding of the discussed concepts will promote therapeutic NM designs for drug delivery systems by leveraging the NMs-membrane interactions and their functions.

The influence of reduced graphene oxide on stem cells: a perspective in peripheral nerve regeneration

Graphene and its derivatives are fascinating materials for their extraordinary electrochemical and mechanical properties. In recent decades, many researchers explored their applications in tissue engineering and regenerative medicine. Reduced graphene oxide (rGO) possesses remarkable structural and functional resemblance to graphene, although some residual oxygen-containing groups and defects exist in the structure. Such structure holds great potential since the remnant-oxygenated groups can further be functionalized or modified. Moreover, oxygen-containing groups can improve the dispersion of rGO in organic or aqueous media. Therefore, it is preferable to utilize rGO in the production of composite materials. The rGO composite scaffolds provide favorable extracellular microenvironment and affect the cellular behavior of cultured cells in the peripheral nerve regeneration. On the one hand, rGO impacts on Schwann cells and neurons which are major components of peripheral nerves. On the other hand, rGO-incorporated composite scaffolds promote the neurogenic differentiation of several stem cells, including embryonic stem cells, mesenchymal stem cells, adipose-derived stem cells and neural stem cells. This review will briefly introduce the production and major properties of rGO, and its potential in modulating the cellular behaviors of specific stem cells. Finally, we present its emerging roles in the production of composite scaffolds for nerve tissue engineering.

Nano-peroxidase a Promising Anti-inflammatory and Antibacterial Agent Against Bacteria and Inflammation Related to Colorectal Cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most common causes of cancer death in the world. Although genes are considered the most importantcauses that contribute to CRC, the intestinal microorganisms are an important player. Recently, various studies ensured the role of microbial infection and the ensuing inflammation in colon cancer initiation and progression. This present study tries to introduce a cheap nano-peroxidase (an antioxidant enzyme) produced from natural sources as efficient and safe antibacterial and anti-inflammatory agent against bacteria and inflammation related to colorectal cancer.

METHODS

Silica nanoparticles were prepared from rice straw. Peroxidase extracted from the dry onion scales was then immobilized on the prepared nanosilica (nano-peroxidase). The antibacterial activity of the prepared nano-peroxidase was tested against the four horsemen bacteria in CRC, Fusobacterium nucleatum, Escherichia coli, Bacteroides fragilis, and Salmonella enterica. The in vitro anti-inflammatory activity of the prepared nano-peroxidase also tests through performing inhibition of albumin denaturation test.

RESULTS

The prepared nano-peroxidase showed high antibacterial activity against the tested bacteria in presence of very low concentration of H2O2. Immobilization increased the peroxidase stability and protected it from hydrolysis enzymes produced by the bacteria. The prepared nano-peroxidase interestingly showed significant higher anti-inflammatory activity than that of the standard (Aspirin).

CONCLUSION

Nano-peroxidase can be considered a promising safe anti-inflammatory and antibacterial agent against bacteria and inflammation related to colorectal cancer.

A bifunctionalized NiCo2O4-Au composite: Intrinsic peroxidase and oxidase catalytic activities for killing bacteria and disinfecting wound

A NiCo₂O₄-Au composite was fabricated following the calcination-reduction method and testified to exhibit the intrinsic high peroxidase- and oxidase-like activities. The composite could activate a low level of H₂O₂ (100 μM) to kill E. coli and S. aureus. NiCo₂O₄-Au composite could be easily separated by an external magnet from the media and reused several times. NiCo₂O₄-Au composite could also effectively damage the existing biofilms and prevent the formation of new biofilms. The electron spin resonance tests showed that NiCo₂O₄-Au composite catalyzed H₂O₂ into reactive oxygen species (ROS), mainly including OH, O₂^-, and ¹O₂; while the oxidase-like activity of NiCo₂O₄-Au also stemmed from the ROS formation in the absence of H₂O₂. The radical trapping experiment confirmed that OH and ¹O₂ were the main radicals in the antibacterial process for NiCo₂O₄-Au in the presence of H₂O₂. A NiCo₂O₄-Au based Band-Aid was also designed, which exhibited high anti-infective and wound-healing properties. This study has demonstrated that NiCo₂O₄-Au composite can be a promising antibacterial agent in environmental and clinical applications.

Intracerebral Injection of Graphene Oxide Nanosheets Mitigates Microglial Activation Without Inducing Acute Neurotoxicity: A Pilot Comparison to Other Nanomaterials

Carbon-based nanomaterials (CNMs) are being explored for neurological applications. However, systematic in vivo studies investigating the effects of CNM nanocarriers in the brain and how brain cells respond to such nanomaterials are scarce. To address this, functionalized multiwalled carbon nanotubes and graphene oxide (GO) sheets are injected in mice brain and compared with charged liposomes. The induction of acute neuroinflammatory and neurotoxic effects locally and in brain structures distant from the injection site are assessed up to 1 week postadministration. While significant neuronal cell loss and sustained microglial cell activation are observed after injection of cationic liposomes, none of the tested CNMs induces either neurodegeneration or microglial activation. Among the candidate nanocarriers tested, GO sheets appear to elicit the least deleterious neuroinflammatory profile. At molecular level, GO induces moderate activation of proinflammatory markers compared to vehicle control. At histological level, brain response to GO is lower than after vehicle control injection, suggesting some capacity for GO to reduce the impact of stereotactic injection on brain. While these findings are encouraging and valuable in the selection and design of nanomaterial-based brain delivery systems, they warrant further investigations to better understand the mechanisms underlying GO immunomodulatory properties in brain.

Nanomaterial-mediated autophagy: coexisting hazard and health benefits in biomedicine

BACKGROUND

Widespread biomedical applications of nanomaterials (NMs) bring about increased human exposure risk due to their unique physicochemical properties. Autophagy, which is of great importance for regulating the physiological or pathological activities of the body, has been reported to play a key role in NM-driven biological effects both in vivo and in vitro. The coexisting hazard and health benefits of NM-mediated autophagy in biomedicine are nonnegligible and require our particular concerns.

MAIN BODY

We collected research on the toxic effects related to NM-mediated autophagy both in vivo and in vitro. Generally, NMs can be delivered into animal models through different administration routes, or internalized by cells through different uptake pathways, exerting varying degrees of damage in tissues, organs, cells, and organelles, eventually being deposited in or excreted from the body. In addition, other biological effects of NMs, such as oxidative stress, inflammation, necroptosis, pyroptosis, and ferroptosis, have been associated with autophagy and cooperate to regulate body activities. We therefore highlight that NM-mediated autophagy serves as a double-edged sword, which could be utilized in the treatment of certain diseases related to autophagy dysfunction, such as cancer, neurodegenerative disease, and cardiovascular disease. Challenges and suggestions for further investigations of NM-mediated autophagy are proposed with the purpose to improve their biosafety evaluation and facilitate their wide application. Databases such as PubMed and Web of Science were utilized to search for relevant literature, which included all published, Epub ahead of print, in-process, and non-indexed citations.

CONCLUSION

In this review, we focus on the dual effect of NM-mediated autophagy in the biomedical field. It has become a trend to use the benefits of NM-mediated autophagy to treat clinical diseases such as cancer and neurodegenerative diseases. Understanding the regulatory mechanism of NM-mediated autophagy in biomedicine is also helpful for reducing the toxic effects of NMs as much as possible.