Nanozymes in Point-of-Care Diagnosis: An Emerging Futuristic Approach for Biosensing

Multifunctional nanozymatic biosensors: Awareness, regulation and pathogenic bacteria detection

It is estimated that approximately 700,000 fatalities occur annually due to infections attributed to various pathogens, which are capable of dissemination via multiple environmental vectors, including air, water, and soil. Consequently, there is an urgent need to enhance and refine rapid detection technologies for pathogens to prevent and control the spread of associated diseases. This review focuses on applying nanozymes in constructing biosensors, particularly their advancement in detecting pathogenic bacteria. Nanozymes, which are nanomaterials exhibiting enzyme-like activity, combine unique magnetic, optical, and electronic properties with structural diversity. This blend of characteristics makes them highly appealing for use in biocatalytic applications. Moreover, their nanoscale dimensions facilitate effective contact with pathogenic bacteria, leading to efficient detection and antibacterial effects. This article briefly summarizes the development, classification, and strategies for regulating the catalytic activity of nanozymes. It primarily focuses on recent advancements in constructing biosensors that utilize nanozymes as probes for sensitively detecting pathogenic bacteria. The discussion covers the development of various optical and electrochemical biosensors, including colorimetric, fluorescence, surface-enhanced Raman scattering (SERS), and electrochemical methods. These approaches provide a reliable solution for the sensitive detection of pathogenic bacteria. Finally, the challenges and future development directions of nanozymes in pathogen detection are discussed.

Emerging trends of biomedical nanotechnology in nutrition, health monitoring and disease diagnosis

The transdisciplinary nature of nanotechnology has facilitated its application across various fields, especially in biological sciences. The primary aim of this review is to consolidate the many facets of nanomedicine, theranostics, and nanotechnology in food preservation into a unified framework and to underscore established research methodologies in the medical domain. Nanoparticles serve a crucial function in improving the bioavailability of orally delivered bioactive substances. This review demonstrated that nanoparticles can enhance the bioavailability of micronutrients, such as vitamin B12, vitamin A, folic acid, and iron. New advances in nanotechnology have made big differences in finding pathogens and killing them specifically, helping people to get better health through medication delivery and imaging, improving food packaging better so it lasts longer, and making foods healthier overall. Nanotechnology currently enhances the safety of delivering highly hazardous medicines through the use of nanozymes that exhibit antioxidant and antibacterial characteristics. Moreover, wearable devices can identify significant alterations in vital signs, medical problems, and infections occurring within the body. We anticipate that these technologies will provide physicians with enhanced direct access to crucial information about the causes of changes in vital signs or diseases, as they are directly connected to the source of the problem. This review paper thoroughly examines the latest developments in nanomaterials and nanozymes as antimicrobial agents in food science and nutrition, wound healing, illness diagnostics, imaging, and potential future uses. The paper presents a concise and structured report on nanotechnology, which will be beneficial to researchers and scientists for future research opportunities.

Development of a Zr/Fe-MIL nanozyme sensor integrated with a user-friendly colorimetric device for glyphosate monitoring

Timely and efficient analysis of glyphosate (GLP) in agriculture and environment is critical for food safety and public health. Herein, a paper-based enzyme sensor integrated with a portable device for GLP monitoring was developed. First, zirconium ions were doped into a typical iron-based MOF (Fe-MIL) via a simple solvothermal method, yielding a Zr/Fe-MIL composite that exhibits remarkable peroxidase-like activity. Zr/Fe-MIL had the capability to sensitively detect GLP, and the sensing mechanism was attributed to the coordination, hydrogen bonding and electrostatic interactions between Zr/Fe-MIL and GLP. Subsequently, a test strip combined with a portable device was designed to integrate automatic extraction, collection, and processing of colorimetric signals, enabling rapid signal analysis and direct concentration output. This system achieved linear ranges of 0.1-1 μg mL-1 and 1-10 μg mL-1, with a low limit of detection (LOD) of 29.1 ng mL-1. The proposed strategy could also be applied to water and food samples (sorghum and soybean) with the recovery rates of 98.53-112.94%. This work provides an effective strategy for the development of portable and user-friendly methods for monitoring GLP.

Ocular drug delivery systems based on nanotechnology: a comprehensive review for the treatment of eye diseases

Ocular drug delivery is a significant challenge due to the intricate anatomy of the eye and the various physiological barriers. Conventional therapeutic approaches, while effective to some extent, often fall short in effectively targeting ocular diseases, resulting in suboptimal therapeutic outcomes due to factors such as poor ocular bioavailability, frequent dosing requirements, systemic side effects, and limited penetration through ocular barriers. This review elucidates the eye's intricate anatomy and physiology, prevalent ocular diseases, traditional therapeutic modalities, and the inherent pharmacokinetic and pharmacodynamic limitations associated with these modalities. Subsequently, it delves into nanotechnology-based solutions, presenting breakthroughs in nanoformulations such as nanocrystals, liposomes, dendrimers, and nanoemulsions that have demonstrated enhanced drug stability, controlled release, and deeper ocular penetration. Additionally, it explores a range of nanosized carriers, including nano-structured lipid carriers, hydrogels, nanogels, nanoenzymes, microparticles, conjugates, exosomes, nanosuspensions, viral vectors, and polymeric nanoparticles, and their applications. Unique insights include emerging innovations such as nanowafers and transcorneal iontophoresis, which indicate paradigm shifts in non-invasive ocular drug delivery. Furthermore, it sheds light on the advantages and limitations of these nanotechnology-based platforms in addressing the challenges of ocular drug delivery. Though nano-based drug delivery systems are drawing increasing attention due to their potential to enhance bioavailability and therapeutic efficacy, the review ends up emphasizing the imperative need for further research to drive innovation and improve patient outcomes in ophthalmology.

In Situ Generation of Porous Ag-Hollandite/Polypyrrole 2D Mats at the Water/Chloroform Interface for Dual Applications in Energy Storage and Electrochemical Sensing

A facile in situ method of the liquid/liquid (L/L) polymerization strategy for synthesizing silver-doped hollandite manganese oxide (Ag-HMO) on polypyrrole (PPy) support is reported for the first time. The highly innovative synthetic method involves producing α-MnO2 attached to PPy oligomers under low-temperature conditions. Subsequently, Ag+ ions are in situ intercalated into the 2 × 2 tunnels in α-MnO2 to generate Ag-HMO-incorporated PPy. Calculations based on density functional theory (DFT) yield negative formation energies, suggesting that Ag-HMO can be formed through the tunnel doping of Ag+ in α-MnO2. Highly crystalline 2D composite mats of Ag-HMO/PPy (PAgMn) with interconnected Ag-HMO nanorod networks with a thickness of ≈1 nm are demonstrated by electron and atomic force microscopy images. Electrochemical detection of formaldehyde on PAgMn-modified screen-printed electrodes opens new prospects for real-time food adulterant sensors. PAgMn is also utilized as electrodes for supercapacitors with a high specific capacitance of 601 mF cm-2. An all-solid-state asymmetric supercapacitor device assembled with PAgMn and activated carbon as negative and positive electrodes demonstrates outstanding energy storage capability with a remarkable energy density of 6.16 mWh cm-2 at a power density of 6300 mW cm-2.

Prospects for the use of nanozyme-based electrochemical and colorimetric sensors for antibiotic detection

Rapid and accurate monitoring of residual antibiotic concentrations is of great importance in environmental monitoring. Therefore, research is active to develop new methods for analyzing antibiotics. Biosensors, including those based on nanozymes, are very successful for antibiotic analysis. Nanozymes (nanomaterials with enzymelike activity) have emerged as a promising solution offering improved stability, cost-effectiveness, and versatility, as compared with natural enzymes. The use of nanozyme-based electrochemical and colorimetric sensors for detecting antibiotics remains underexplored. This review presents the main prospects for the use of electrochemical and colorimetric nanozyme sensor systems to detect antibiotics. It identifies major shortcomings of these platforms and ways to deal with them. Finally, it highlights the advantages of these sensors over other systems and explains the main mechanisms of signal generation for antibiotic detection.

Vanadium single-atoms coordinated artificial peroxidases as biocatalyst-linked immunosorbent assay for highly-sensitive carcinoembryonic antigen immunoassay

In medical and biomedical fields, enzyme-mimetic nanomaterials have garnered significant interest as efficacious signal enhancers for biocatalyst-linked immunosorbent assays (BLISA). Despite the burgeoning enthusiasm, engineering artificial biocatalysts that exhibit both exceptional catalytic proficiency and pronounced colorimetric signal output remains a formidable challenge. Inspired by the heme structures and biocatalytic activities of horseradish peroxidase, we introduce the synthesis of vanadium single-atoms (SAV) coordinated artificial peroxidases as BLISA for highly sensitive and selective carcinoembryonic antigen (CEA) immunoassay. Our synthesized SAV exhibits peroxidase (POD)-like activity that is both efficacious and highly specific, surpassing the performance of many other single-atom-structured materials. The SAV-linked immunoassay demonstrates an ultrasensitive response to the target antigen (CEA), with a linear detection range spanning 0.03-10 ng/mL and an impressively low detection limit of 0.335 ng/mL. This straightforward and robust immunoassay technique not only achieves superior signal amplification compared to traditional natural enzymes but also boasts high precision, commendable reproducibility, and remarkable specificity, aligning closely with conventional enzyme-linked immunosorbent assay for CEA detection in serum samples. This study offers a blueprint for designing artificial peroxidase-based colorimetric nanosystems, promoting the evolution of ultrasensitive BLISA applications for the early diagnosis and intervention of cancer.

Nanozymes in biomedicine: Unraveling trends, research foci, and future trajectories via bibliometric insights (from 2007 to 2024)

Nanozymes, a new generation of artificial enzymes, have attracted significant attention in biomedical applications due to their multifunctional properties, multi-enzyme mimicking abilities, cost-effectiveness, and high stability. Leveraging these diverse catalytic activities, an increasing number of nanozyme-based therapeutic strategies have been developed for the treatment of various diseases. Despite substantial research efforts, a significant gap remains in comprehensive studies examining the progression, key areas, current trends, and future directions in this field. This study provides a comprehensive overview of nanozyme applications in biomedical research over the past 17 years, utilizing data from the Web of Science Core Collection, covering the period from January 1, 2007, to October 8, 2024. Advanced bibliometric and visualization tools were employed to facilitate a comprehensive analysis. The results highlight China's dominant role in this field, accounting for 76.83 % of total publications, significantly influencing the evolution of research in this area. Key contributions were made by institutions such as the Chinese Academy of Sciences, the University of Chinese Academy of Sciences, and the University of Science and Technology of China, with Qu Xiaogang as the leading author. The journal ACS Applied Materials & Interfaces has become the most prolific publisher in this field. Keyword analysis indicates that since 2022, research hotspots in this field have increasingly focused on areas such as photothermal therapy, chemodynamic therapy, and ferroptosis. Challenges such as obstacles to clinical translation, limitations in recyclability, and insufficient targeting ability were addressed. The potential applications of emerging interdisciplinary technologies, such as artificial intelligence, machine learning, and organoids, in advancing nanozyme development were explored. This study offers a data-driven roadmap for researchers to navigate the evolving landscape of nanozyme innovation, emphasizing interdisciplinary collaboration in impactful biomedical applications.

Intervening with nanozymes in aging-related diseases: Strategies for restoring mitochondrial function

The decline in mitochondrial function has been identified as one of the central pathological mechanisms underlying a variety of aging-related diseases. Nanozymes are nanomaterials with intrinsic enzyme-like properties and are important alternatives to natural enzymes. As emerging biocatalysts, nanozymes exhibit significant potential in mimicking the activity of natural enzymes, enhancing mitochondrial function, and offering novel therapeutic strategies for aging-related conditions. This review provides an overview of various approaches to modulate the catalytic activity of nanozymes, considering factors such as particle size, shape, surface modifications, and constituent elements. It then examines the role of nanozymes in mitigating aging-related diseases by preserving mitochondrial health, with a particular focus on their ability to regulate three critical aspects: mitochondrial energy metabolism, quality control, and antioxidant capacity. By improving mitochondrial energy generation, supporting mitochondrial integrity, and eliminating excess reactive oxygen species (ROS), nanozymes offer new therapeutic possibilities for neurodegenerative diseases, bone-related disorders, and diabetes. Finally, this article discusses the major challenges faced in this field, including issues such as the scalability, biocompatibility, and targeting ability of nanozymes. It also emphasizes that future research should focus on enhancing clinical translation to ensure that nanozymes can play an effective role in practical therapeutic applications.

Multifunctional cerium nanolabels in electrochemical immunosensing with improved robustness and performance: determination of TIM-1 in colorectal cancer scenarios as a case study

A multifunctional cerium oxide nanoparticles (CeO2NPs)-based nanolabel is exploited to implement an electrochemical sandwich-type immunoplatform for the determination of T-cell immunoglobulin and mucin domain 1 (TIM-1) biomarker, a mucin-like class I membrane glycoprotein associated with cancer angiogenesis. The immunoplatform is constructed using screen-printed electrodes where capture antibody is immobilized through the chemistry of diazonium salts. CeO2NPs exhibit robust pseudo-peroxidase activity even at high substrate concentrations. They are covalently functionalized in a simple manner after carboxylation with a detector antibody (dAb), acting dually as a nanozyme and nanocarrier for sensing bioreceptors. This allows the development of immunoplatforms with improved robustness and performance (in terms of a moderate enhancement in sensitivity, a significant expansion in the linear range, and a reduction in the background current) compared with the immunoplatforms prepared using nanolabels also decorated with the natural enzyme (horseradish peroxidase, HRP) or the conventional enzymatic labeling involving the dAb and an HRP-secondary antibody. Under the optimized experimental conditions, the developed electrochemical immunoplatform allows the highly sensitive detection of the TIM-1 glycoprotein, with a detection limit of 9.9 pg mL-1 and a linear working range of 33-600 pg mL-1. This performance permits biomarker quantification within clinically relevant ranges. This innovative configuration enables the precise diagnosis and stratification of colorectal cancer patients by analyzing plasma samples without pretreatment beyond a sample dilution and allows establishment of the first cut-off values reported for this purpose.

Construction of a CuO2@PDA Nanozyme with Switchable Dual Enzyme-Mimic Activities for Colorimetric Sensing of Catechol and Hydroquinone

The development of metal-based redox nanozymes represents a new frontier in pollutant sensing. In this field, designing highly active nanozymes and precisely regulating their enzymatic activity are key challenges. In this work, we report the construction of a copper peroxide@polydopamine (CuO2@PDA) nanozyme with dual enzyme-like activity, mimicking the active centers of laccase and peroxidase. Here, CuO2 acts as the catalytic center, while PDA serves as a carrier to prevent CuO2 aggregation and promotes conversion of CuII/CuI active sites via the reduction effect of its surface catechol groups to complete the catalytic cycle. As expected, the obtained CuO2@PDA nanozyme exhibits significant laccase- and peroxidase-mimetic activities. Moreover, its dual enzymatic activity can be systematically switched by adjusting pH and temperature. Specifically, laccase activity dominates near neutral pH, while CuO2 decomposition into Cu ions and H2O2 at acidic pH triggers peroxidase activity. Similarly, CuO2@PDA exhibits temperature-dependent dual enzymatic activity with peroxidase activity prevailing at low temperatures and laccase activity at high temperatures. According to enzymatic performance and XPS results, a possible catalytic mechanism of the dual enzymatic activity of CuO2@PDA has been proposed. Then, based on the pH-dependent dual enzymatic activity of CuO2@PDA, we constructed a detection system for the isomers of organic pollutants, catechol (CC) and hydroquinone (HQ). The laccase-like activity of CuO2@PDA enables direct oxidation of CC into yellow o-benzoquinone, while HQ discolors the preoxidized substrate generated via the peroxidase-like activity of CuO2@PDA. Moreover, selective sensing for CC and HQ with high sensitivity was achieved in real water samples. This approach can guide the design of nanozymes with multienzymatic activity and unveil their potential uses in environmental pollutant discrimination.

Nanozyme-Enabled Biomedical Diagnosis: Advances, Trends, and Challenges

As nanoscale materials with the function of catalyzing substrates through enzymatic kinetics, nanozymes are regarded as potential alternatives to natural enzymes. Compared to protein-based enzymes, nanozymes exhibit attractive characteristics of low preparation cost, robust activity, flexible performance adjustment, and versatile functionalization. These advantages endow them with wide use from biochemical sensing and environmental remediation to medical theranostics. Especially in biomedical diagnosis, the feature of catalytic signal amplification provided by nanozymes makes them function as emerging labels for the detection of biomarkers and diseases, with rapid developments observed in recent years. To provide a comprehensive overview of recent progress made in this dynamic field, here an overview of biomedical diagnosis enabled by nanozymes is provided. This review first summarizes the synthesis of nanozyme materials and then discusses the main strategies applied to enhance their catalytic activity and specificity. Subsequently, representative utilization of nanozymes combined with biological elements in disease diagnosis is reviewed, including the detection of biomarkers related to metabolic, cardiovascular, nervous, and digestive diseases as well as cancers. Finally, some development trends in nanozyme-enabled biomedical diagnosis are highlighted, and corresponding challenges are also pointed out, aiming to inspire future efforts to further advance this promising field.

Recent Advances in Nanoenzymes Based Therapies for Glioblastoma: Overcoming Barriers and Enhancing Targeted Treatment

Glioblastoma multiforme (GBM) is a highly aggressive and malignant brain tumor originating from glial cells, characterized by high recurrence rates and poor patient prognosis. The heterogeneity and complex biology of GBM, coupled with the protective nature of the blood-brain barrier (BBB), significantly limit the efficacy of traditional therapies. The rapid development of nanoenzyme technology presents a promising therapeutic paradigm for the rational and targeted treatment of GBM. In this review, the underlying mechanisms of GBM pathogenesis are comprehensively discussed, emphasizing the impact of the BBB on treatment strategies. Recent advances in nanoenzyme-based approaches for GBM therapy are explored, highlighting how these nanoenzymes enhance various treatment modalities through their multifunctional capabilities and potential for precise drug delivery. Finally, the challenges and therapeutic prospects of translating nanoenzymes from laboratory research to clinical application, including issues of stability, targeting efficiency, safety, and regulatory hurdles are critically analyzed. By providing a thorough understanding of both the opportunities and obstacles associated with nanoenzyme-based therapies, future research directions are aimed to be informed and contribute to the development of more effective treatments for GBM.

Nanozyme-based wearable biosensors for application in healthcare

Recent years have witnessed tremendous advances in wearable sensors, which play an essential role in personalized healthcare for their ability for real-time sensing and detection of human health information. Nanozymes, capable of mimicking the functions of natural enzymes and addressing their limitations, possess unique advantages such as structural stability, low cost, and ease of mass production, making them particularly beneficial for constructing recognition units in wearable biosensors. In this review, we aim to delineate the latest advancements in nanozymes for the development of wearable biosensors, focusing on key developments in nanozyme immobilization strategies, detection technologies, and biomedical applications. The review also highlights the current challenges and future perspectives. Ultimately, it aims to provide insights for future research endeavors in this rapidly evolving area.

New horizons for the therapeutic application of nanozymes in cancer treatment

The advent of nanozymes has revolutionized approaches to cancer diagnosis and therapy, introducing innovative strategies that address the limitations of conventional treatments. Nanozyme nanostructures with enzyme-mimicking catalytic abilities exhibit exceptional stability, biocompatibility, and customizable functions, positioning them as promising tools for cancer theranostics. By emulating natural enzyme reactions, nanozymes can selectively target and eradicate cancer cells, minimizing harm to adjacent healthy tissues. Nanozymes can also be functionalized with specific targeting ligands, allowing for the precise delivery and regulated release of therapeutic agents, improving treatment effectiveness and reducing adverse effects. However, issues such as biocompatibility, selectivity, and regulatory compliance remain critical challenges for the clinical application of nanozymes. This review provides an overview of nanozymes, highlighting their unique properties, various classifications, catalytic activities, and diverse applications in cancer treatments. The strategic oncological deployment of nanozymes could profoundly impact future advancements in personalized medicine, highlighting recent progress and prospective directions in enzyme-mimetic approaches for cancer treatment. This review summarizes an overview of nanozymes, highlighting their unique properties, various classifications, catalytic activities, and diverse applications in cancer treatments.

Dual-Mode Immunosensor for Antibody Detection: Harnessing the Versatility of Antibody-Based Nanozymes across Optical and Electrochemical Platforms

In the early years of the 21st century, numerous viral infectious diseases have proliferated, prompting intensified efforts to devise more effective diagnostic methods. In response, various biosensors have emerged with the aim of overcoming the constraints of conventional diagnostic techniques. Nanomaterial-based biosensors have revolutionized conventional approaches, significantly enhancing biosensor performance and effectively tackling these challenges. A diverse array of nanoparticles and nanomaterials has been systematically synthesized, engineered, and employed to augment the functionalities of biosensors. This work capitalizes on the properties of gold-platinum bimetallic nanoclusters (NCs) embedded in the structure of an immunoglobulin (IgG) (Au/Pt NCs-IgG), unveiling a novel double strategy for the detection of antibodies that leverages both their catalytic NC scaffold and the biorecognition element. The detection mechanism revealed the unique oxidase-like properties of Au/Pt NCs-IgG. This distinctive property, in addition to previously reported peroxidase-like activity, positions Au/Pt NCs-IgG as an effective probe in both optical and electrochemical sandwich enzyme-linked immunosorbent assays, facilitating their incorporation in different sensor frameworks and their utilization across various applications. As a study case, anti-SARS-CoV-2 antibodies (anti-RBD IgG antibodies) were employed as the target analyte. A linear detection range was found between 0.5 and 100 ng/mL for optical immunosensors and 50-300 ng/mL for electrochemical immunosensors. The validation of the immunosensor in clinical samples demonstrated its promising diagnostic value. The significantly differential signal obtained between positive and negative clinical samples underscores the suitability of both sensors for point-of-care diagnostic applications.

Nanozyme-based aptasensors for the detection of tumor biomarkers

A nanozyme-based aptasensor combines the unique properties of nanozymes with the specificity of aptamers for the detection of various biomolecules. Nanozymes are nanomaterials that possess enzyme-like properties, demonstrating substantial potential for enhancing the sensing capabilities of biosensors. In recent years, the incorporation of nanozymes into biosensors has opened new avenues for the detection of tumor biomarkers. The unique attributes of nanozymes and aptamers lead to biosensors characterized by high sensitivity, specificity, reproducibility and accuracy in analytical performance. This article reviews the research progress of nanozyme-based aptasensors in tumor biomarker detection over the past decade. We categorize these sensors based on their sensing modes and target types, and examine the properties and applications of the nanozymes employed in these devices, providing a thorough discussion of the strengths and weaknesses associated with each sensor type. Finally, the review highlights the strengths and challenges associated with nanozyme-based biosensors and envisions future developments and applications in this field. The objective is to provide insights for improving biosensor performance in tumor biomarker detection, thereby contributing to advancements in precision cancer diagnosis and treatment.

Inside out: Exploring edible biocatalytic biosensors for health monitoring

Edible biosensors can measure a wide range of physiological and biochemical parameters, including temperature, pH, gases, gastrointestinal biomarkers, enzymes, hormones, glucose, and drug levels, providing real-time data. Edible biocatalytic biosensors represent a new frontier within healthcare technology available for remote medical diagnosis. The main challenges to develop edible biosensors are: i) finding edible materials (i.e. redox mediators, conductive materials, binders and biorecognition elements such as enzymes) complying with Food and Drug Administration (FDA), European Food Safety Authority (EFSA) and European Medicines Agency (EMEA) regulations; ii) developing bioelectronics able to operate in extreme working conditions such as low pH (∼pH 1.5 gastric fluids etc.), body temperature (between 37 °C and 40 °C) and highly viscous bodily fluids that may cause surface biofouling issues. Nowadays, advanced printing techniques can revolutionize the design and manufacturing of edible biocatalytic biosensors. This review outlines recent research on biomaterials suitable for creating edible biocatalytic biosensors, focusing on their electrochemical properties such as electrical conductivity and redox potential. It also examines biomaterials as substrates for printing and discusses various printing methods, highlighting challenges and perspectives for edible biocatalytic biosensors.

Tunable multi-enzyme activities of platinum nanoclusters for enhanced specificity and sensitivity in biosensing

Nanozymes have gained prominence for their utility in biosensing and disease diagnostics. However, challenges arise from complex sample matrices and nonspecific enzyme activities that contribute to false signals. This study introduces multifunctional platinum nanoclusters (Pt NCs) exhibiting peroxidase-like (POD-like), oxidase-like (OXD-like), and laccase-like activities tailored for enhanced biosensing capabilities. By adjusting pH, we optimized the conditions to achieve distinct POD-like and OXD-like responses, thereby reducing background signals and improving detection accuracy. The addition of ATP further amplified the POD-like activity while minimizing interference from OXD-like activity. This combined strategy substantially enhanced biomarker detection selectivity, demonstrated through glucose detection in human serum samples. Moreover, thiol inhibition of laccase-like activity in Pt NCs was leveraged for thiol-based antioxidant assessment, revealing their application in quantifying total antioxidant capacity (TAC) in human liver cancer cells, accounting for 44 % of TAC. The Pt NCs demonstrated robust sensitivity and reusability, offering a novel multi-enzyme nanomaterial with potential for precise and interference-free biosensing applications. These findings contribute to the development of advanced nanozyme-based biosensors, addressing specificity regulation challenges and expanding their practical application in biosensing and disease diagnostics.

A Self-Powered Enzymatic Glucose Sensor Utilizing Bimetallic Nanoparticle Composites Modified Pencil Graphite Electrodes as Cathode

Enzymatic biofuel cells (EBFC) are promising sources of green energy owing to the benefits of using renewable biofuels, eco-friendly biocatalysts, and moderate operating conditions. In this study, a simple and effective EBFC was presented using an enzymatic composite material-based anode and a nonenzymatic bimetallic nanoparticle-based cathode respectively. The anode was constructed from a glassy carbon electrode (GCE) modified with a multi-walled carbon nanotube (MWCNT) and ferrocene (Fc) as a conductive layer coupled with the enzyme glucose oxidase (GOx) as a sensitive detection layer for glucose. A chitosan layer was also applied to the electrode as a protective layer to complete the composite anode. Chronoamperometry (CA) results show that the MWCNT-Fc-GOx/GCE electrode has a linear relationship between current and glucose concentration, which varied from 1 to 10 mM. The LOD and LOQ were calculated for anode as 0.26 mM and 0.87 mM glucose, respectively. Also the sensitivity of the proposed sensor was calculated as 25.71 μ A/mM. Moreover, the studies of some potential interferants show that there is no significant interference for anode in the determination of glucose except ascorbic acid (AA), uric acid (UA), and dopamine (DA). On the other hand, the cathode consisted of a disposable pencil graphite electrode (PGE) modified with platinum-palladium bimetallic nanoparticles (Nps) which exhibit excellent conductivity and electron transfer rate for the oxygen reduction reaction (ORR). The constructed EBFC was optimized and characterized using various electroanalytical techniques. The EBFC consisting of MWCNT-Fc-GOx/GCE anode and Pt-PdNps/PGE cathode exhibits an open circuit potential of 285.0 mV and a maximum power density of 32.25 µW cm-2 under optimized conditions. The results show that the proposed EBFC consisting of an enzymatic composite-based anode and bimetallic nanozyme-based cathode is a unique design and a promising candidate for detecting glucose while harvesting power from glucose-containing natural or artificial fluids.

A Cross-talk between Nanomedicines and Cardiac Complications: Comprehensive View

Background:

Cardiovascular Diseases (CVDs) are the leading cause of global morbidity and mortality, necessitating innovative approaches for both therapeutics and diagnostics. Nanoscience has emerged as a promising frontier in addressing the complexities of CVDs.

Objective:

This study aims to explorethe interaction of CVDs and Nanomedicine (NMs), focusing on applications in therapeutics and diagnostics.

Observations:

In the realm of therapeutics, nanosized drug delivery systems exhibit unique advantages, such as enhanced drug bioavailability, targeted delivery, and controlled release. NMs platform, including liposomes, nanoparticles, and carriers, allows the precise drug targeting to the affected cardiovascular tissues with minimum adverse effects and maximum therapeutic efficacy. Moreover, nanomaterial (NM) enables the integration of multifunctional components, such as therapeutic agents and target ligands, into a single system for comprehensive CVD management. Diagnostic fronts of NMs offer innovative solutions for early detection and monitoring of CVDs. Nanoparticles and nanosensors enable highly sensitive and specific detection of Cardiac biomarkers, providing valuable insights into a disease state, its progression, therapeutic outputs, etc. Further, nano-based technology via imaging modalities offers high high-resolution imaging, aiding in the vascularization of cardiovascular structures and abnormalities. Nanotechnology-based imaging modalities offer high-resolution imaging and aid in the visualization of cardiovascular structures and abnormalities.

Conclusion:

The cross-talk of CVDs and NMs holds tremendous potential for revolutionizing cardiovascular healthcare by providing targeted and efficient therapeutic interventions, as well as sensitive and early detection for the improvement of patient health if integrated with Artificial Intelligence (AI).

POD-like nanozyme constructed from perspective of charge transfer engineering for biosensing of magnetic separation treated Listeria monocytogenes

For foodborne pathogens pose a serious threat to public health, a magnetic separation strategy and a nanozyme-based biosensor are proposed for biosensing of Listeria monocytogenes (L. monocytogenes). In this work, doripenem is selected as a recognized molecule for the modification of magnetic beads to capture L.monocytogenes in food and environmental samples. Furthermore, the POD-like MXene-Hemin-Au is constructed from perspective of charge transfer engineering which provides a vivid example to rational design of nanozymes. Finally, the captured L.monocytogenes is labeled with MXene-Hemin-Au@mAb, forming the sandwich complexes for quantitative determination. The current signals that generated by the complexes exhibit a good linear relationship with a limit of detection of 2.3 × 101 CFU/mL. The biosensor shows a satisfactory applicability in real samples with recoveries of 91.19% to 102.98%. Overall, the biosensor with integrated magnetic separation strategy presents a potential approach for high sensitivity biosensing of foodborne pathogens.

Probiotics Bi-Enzymatic Cascade Repair System for Editing the Inflammatory Microenvironment to Boost Probiotic Therapy in Inflammatory Bowel Disease

Inflammatory bowel disease presents significant treatment challenges owing to its complex pathology. Although probiotics have shown promise as a therapeutic option, their effectiveness is often limited by low concentrations at sites of inflammation, exacerbated by excessive reactive oxygen species and inflammatory triggers. To address this, an innovative cascade repair system is developed to enhance probiotic therapeutic impact by modulating the intestinal microenvironment. This system uses iMXene's catalytic properties to neutralize reactive oxygen species in the gut and its capacity to deliver the CRISPR/dCas9 gene editing system to activate the NLR family pyrin domain containing 12 genes, helping suppress inflammation. By promoting the colonization of Lactobacillus rhamnosus, the system inhibits inflammation pathways and supports the restoration of a balanced intestinal flora through a cascade repair mechanism. These findings demonstrate significant therapeutic benefits in experimental models, with improvements in the overall well-being of treated mice and effective repair of intestinal inflammation damage. This pioneering approach holds promise for inflammatory bowel disease treatment and opens new avenues for managing other inflammatory conditions, offering valuable insights and guidance for future research into inflammatory diseases.

A Cross-talk between Nanomedicines and Cardiac Complications: Comprehensive View

BACKGROUND

Cardiovascular Diseases (CVDs) are the leading cause of global morbidity and mortality, necessitating innovative approaches for both therapeutics and diagnostics. Nanoscience has emerged as a promising frontier in addressing the complexities of CVDs.

OBJECTIVE

This study aims to explore the interaction of CVDs and Nanomedicine (NMs), focusing on applications in therapeutics and diagnostics.

OBSERVATIONS

In the realm of therapeutics, nanosized drug delivery systems exhibit unique advantages, such as enhanced drug bioavailability, targeted delivery, and controlled release. NMs platform, including liposomes, nanoparticles, and carriers, allows the precise drug targeting to the affected cardiovascular tissues with minimum adverse effects and maximum therapeutic efficacy. Moreover, Nanomaterial (NM) enables the integration of multifunctional components, such as therapeutic agents and target ligands, into a single system for comprehensive CVD management. Diagnostic fronts of NMs offer innovative solutions for early detection and monitoring of CVDs. Nanoparticles and nanosensors enable highly sensitive and specific detection of Cardiac biomarkers, providing valuable insights into a disease state, its progression, therapeutic outputs, etc. Further, nano-based technology via imaging modalities offers high high-resolution imaging, aiding in the vascularization of cardiovascular structures and abnormalities. Nanotechnology-based imaging modalities offer high-resolution imaging and aid in the visualization of cardiovascular structures and abnormalities.

CONCLUSION

The cross-talk of CVDs and NMs holds tremendous potential for revolutionizing cardiovascular healthcare by providing targeted and efficient therapeutic interventions, as well as sensitive and early detection for the improvement of patient health if integrated with Artificial Intelligence (AI).

Tailoring metal oxide nanozymes for biomedical applications: trends, limitations, and perceptions

Nanomaterials with enzyme-like properties are known as 'nanozymes'. Nanozymes are preferred over natural enzymes due to their nanoscale characteristics and ease of tailoring of their physicochemical properties such as size, structure, composition, surface chemistry, crystal planes, oxygen vacancy, and surface valence state. Interestingly, nanozymes can be precisely controlled to improve their catalytic ability, stability, and specificity which is unattainable by natural enzymes. Therefore, tailor-made nanozymes are being favored over natural enzymes for a range of potential applications and better prospects. In this context, metal oxide nanoparticles with nanozyme-mimicking characteristics are exclusively being used in biomedical sectors and opening new avenues for future nanomedicine. Realising the importance of this emerging area, here, we discuss the mechanistic actions of metal oxide nanozymes along with their key characteristics which affect their enzymatic actions. Further, in this critical review, the recent progress towards the development of point-of-care (POC) diagnostic devices, cancer therapy, drug delivery, advanced antimicrobials/antibiofilm, dental caries, neurodegenerative diseases, and wound healing potential of metal oxide nanozymes is deliberated. The advantages of employing metal oxide nanozymes, their potential limitations in terms of nanotoxicity, and possible prospects for biomedical applications are also discussed with future recommendations.

Advances in machine learning-enhanced nanozymes

Nanozymes, synthetic nanomaterials that mimic the catalytic functions of natural enzymes, have emerged as transformative technologies for biosensing, diagnostics, and environmental monitoring. Since their introduction, nanozymes have rapidly evolved with significant advancements in their design and applications, particularly through the integration of machine learning (ML). Machine learning (ML) has optimized nanozyme efficiency by predicting ideal size, shape, and surface chemistry, reducing experimental time and resources. This review explores the rapid advancements in nanozyme technology, highlighting the role of ML in improving performance across various bioapplications, including real-time monitoring and the development of chemiluminescent, electrochemical and colorimetric sensors. We discuss the evolution of different types of nanozymes, their catalytic mechanisms, and the impact of ML on their property optimization. Furthermore, this review addresses challenges related to data quality, scalability, and standardization, while highlighting future directions for ML-driven nanozyme development. By examining recent innovations, this review highlights the potential of combining nanozymes with ML to drive the development of next-generation diagnostic and detection technologies.

The Exploration of Nanozymes for Biosensing of Pathological States Tailored to Clinical Theranostics

The nanozymes (NZs) are the artificial catalyst deployed for biosensing with their uniqueness (high robustness, surface tenability, inexpensive, and stability) for obtaining a better response/miniaturization of the varied sensors than their traditional ancestors. Nowadays, nanomaterials with their broadened scale such as metal-organic frameworks (MOFs), and metals/metal oxides are widely engaged in generating NZ-based biosensors (BS). Diverse strategies like fluorescent, colorimetric, surface-enhanced Raman scattering (SERS), and electrochemical sensing principles were implemented for signal transduction of NZs. Despite broad advantages, numerous encounters (like specificity, feasibility, stability, and issues in scale-up) are affecting the potentialities of NZs-based BS, and thus need prior attention for a promising exploration for a revolutionary outcome in advanced theranostics. This review includes different types of NZs, and the progress of numerous NZs tailored bio-sensing techniques in detecting abundant bio analytes for theranostic purposes. Further, the discussion highlighted some recent challenges along with their progressive way of possibly overcoming followed by commercial outbreaks.

Synergistic Role of the AuAg-Fe3O4 Nanoenzyme for Ultrasensitive Immunoassay of Dengue Virus

A combination of magnetic and noble metal nanoparticles (NPs) has recently emerged as a potential substance for rapid and sensitive immunosorbent assays. However, to make the assay an alternative method for Enzyme-linked immunosorbent assay, the individual role of each nanoparticle must be explored properly. In this work, an immunoassay has been proposed using two antibody-conjugated iron oxide nanoparticles (Fe3O4NPs) and gold-silver bimetallic nanoparticles (AuAgNPs) to enhance the sensitivity of virus detection by colorimetric TMB/H2O2 signal amplification. A synergistic effect is monitored between Fe3O4NPs and AuAgNPs, which is explored for colorimetric virus detection. The sensor exploits the synergistic effect between the nanoparticles to successfully detect a wide range of dengue virus-like particle (DENV-LP) concentrations ranging from 10 to 100 pg/mL with a detection limit of up to 2.6 fg/mL. In the presence of a target DENV-LP, a sandwich-like structure is formed, which restricts the electron transfer and the associated synergistic effect between the nanoparticles, restricting the TMB oxidation process. Therefore, the synergistic effect is the key to the present work, which accounts for the enhanced rate of the enzymatic reaction on TMB and makes the current method of virus detection more sensitive and reliable compared to the others.

Exploring Nanozymes for Organic Substrates: Building Nano-organelles

Since the discovery of the first peroxidase nanozyme (Fe3O4), numerous nanomaterials have been reported to exhibit intrinsic enzyme-like activity toward inorganic oxygen species, such as H2O2, oxygen, and O2 -. However, the exploration of nanozymes targeting organic compounds holds transformative potential in the realm of industrial synthesis. This review provides a comprehensive overview of the diverse types of nanozymes that catalyze reactions involving organic substrates and discusses their catalytic mechanisms, structure-activity relationships, and methodological paradigms for discovering new nanozymes. Additionally, we propose a forward-looking perspective on designing nanozyme formulations to mimic subcellular organelles, such as chloroplasts, termed "nano-organelles". Finally, we analyze the challenges encountered in nanozyme synthesis, characterization, nano-organelle construction and applications while suggesting directions to overcome these obstacles and enhance nanozyme research in the future. Through this review, our goal is to inspire further research efforts and catalyze advancements in the field of nanozymes, fostering new insights and opportunities in chemical synthesis.

Lattice expansion in ruthenium nanozymes improves catalytic activity and electro-responsiveness for boosting cancer therapy

Nanozymes have been attracting widespread interest for the past decade, especially in the field of cancer therapy, due to their intrinsic catalytic activities, strong stability, and ease of synthesis. However, enhancing their catalytic activity in the tumor microenvironment (TME) remains a major challenge. Herein, we manipulate catalytic activities of Ru nanozymes via modulating lattice spacing in Ru nanocrystals supported on nitrogen-doped carbon support, to achieve improvement in multiple enzyme-like activities that can form cascade catalytic reactions to boost cancer cell killing. In addition, the lattice expansion in Ru nanocrystals improve the responsiveness of the nanozymes to self-powered electric field, achieving maximized cancer therapeutic outcome. Under the electrical stimulation provided by a human self-propelled triboelectric device, the Ru-based nanozyme (Ru1000) with a lattice expansion of 5.99% realizes optimal catalytic performance and cancer therapeutic outcome of breast cancer in female tumor-bearing mice. Through theoretical calculations, we uncover that the lattice expansion and electrical stimulation promote the catalytic reaction, simultaneously, by reducing the electron density and shifting the d-band center of Ru active sites. This work provides opportunities for improving the development of nanozymes.

The biomedical applications of nanozymes in orthopaedics based on regulating reactive oxygen species

Nanozymes, a category of nanomaterials with enzyme-like activity, have garnered growing interest in various biomedical contexts. Notably, nanozymes that are capable of regulating reactive oxygen species levels by emulating antioxidant or prooxidant enzymes within cells hold significant therapeutic potential for a range of disorders. Herein, we overview the catalytic mechanisms of four exemplary nanozymes within the orthopedic domain. Subsequently, we emphasize recent groundbreaking advancements in nanozyme applications in orthopaedics, encompassing osteoarthritis, osteoporosis, intervertebral disc degeneration, bone defects, spinal cord injury, gout, rheumatoid arthritis, osteosarcoma and bone infection. Furthermore, we discuss the emerging area's future prospects and several noteworthy challenges in biomedical application. This review not only fosters the ongoing development of nanozyme research but also fosters the emergence of more potent nanozymes for the treatment of orthopaedical diseases in the future.

Visual and colorimetric detection of microRNA in clinical samples based on strand displacement amplification and nanozyme-mediated CRISPR-Cas12a system

The sensitive and accurate detection of target microRNA is especially important for the diagnosis, staging, and treatment of hepatocellular carcinoma (HCC). Herein, we report a simple strand displacement and CRISPR-Cas12a amplification strategy with nanozymes as a signal reporter for the binary visual and colorimetric detection of the HCC related microRNA. Pt@Au nanozymes with excellent peroxidase enzyme activity were prepared and linked to magnetic beads via a single-stranded DNA (ssDNA) linker. The target microRNA was designed to trigger strand displacement amplification and release a DNA promoter to activate the CRISPR-Cas12a system. The activated CRISPR-Cas12a system efficiently cleaved the linker ssDNA and released Pt@Au nanozymes from magnetic beads to induce the colorimetric reaction of 3,3',5,5'-tetramethylbenzidine. The strand displacement amplification converted the single microRNA input into abundant DNA promoter output, which improved the detection sensitivity by over two orders of magnitude. Through integration of strand displacement amplification and the nanozyme-mediated CRISPR-Cas12a system, limits of detection of 0.5 pM and 10 pM for miRNA-21 were achieved with colorimetric and visual readouts, respectively. The proposed strategy can achieve accurate quantitative detection of miRNA-21 in the range from 1 pM to 500 pM. The detection results for miRNA-21 using both colorimetric and visual readouts were validated in 40 clinical serum samples. Significantly, the proposed strategy achieved visual HCC diagnosis with the naked eye and could distinguish distinct Barcelona clinical HCC stages by colorimetric detection, showing good application prospects for sensitive and facile point-of-care testing for HCC.

Smart Nanozymes for Diagnosis of Bacterial Infection: The Next Frontier from Laboratory to Bedside Testing

The global spread of infectious diseases caused by pathogenic bacteria significantly poses public health concerns, and methods for sensitive, selective, and facile diagnosis of bacteria can efficiently prevent deterioration and further spreading of the infections. The advent of nanozymes has broadened the spectrum of alternatives for diagnosing bacterial infections. Compared to natural enzymes, nanozymes exhibit the same enzymatic characteristics but offer greater economic efficiency, enhanced durability, and adjustable dimensions. The importance of early diagnosis of bacterial infection and conventional diagnostic approaches is introduced. Subsequently, the review elucidates the definition, properties, and catalytic mechanism of nanozymes. Eventually, the detailed application of nanozymes in detecting bacteria is explored, highlighting their utilization as biosensors that allow for accelerated and highly sensitive identification of bacterial infections and reflecting on the potential of nanozyme-based bacterial detection as a point-of-care testing (POCT) tool. A brief summary of obstacles and future perspectives in this field is presented at the conclusion of this review.

Light-Controlled Regulation of Dual-Enzyme Properties in YbGd-Carbon Quantum Dots Nano-Hybrid for Advanced Biosensing

Compared to nanozymes with single enzyme activity, those with multiple enzyme activities possess broader application potential due to their diversified enzymatic functionalities. However, the multienzyme nanozymes currently face challenges of interference among different enzymatic activities during practical applications. In this study, we report the synthesis of a light-responsive YbGd-carbon quantum dots nano-hybrid, termed YbGd-CDs, which exhibits controllable enzyme-mimicking activities. This light-responsive behavior enables selective control of the enzymatic activities. Under visible light irradiation, YbGd-CDs demonstrate robust oxidase-like activity. Conversely, under dark conditions, they primarily exhibit peroxidase-like activity. Leveraging the dual-enzyme-mimicking capabilities of YbGd-CDs, we developed colorimetric assays for sensitive detection of total antioxidant capacity (TAC) in both normal and cancer cells as well as d-amino acids in human saliva. This study not only advances the synthesis of carbon-based nanozymes but also highlights their potential in biosensing applications.

Bifunctional oxidase-peroxidase mimicking Fe-Ce MOF on paper-based analytical devices to intensify luminol chemiluminescence: Application for measuring different sugars with a smartphone readout

This study presents a potent paper-based analytical device (PAD) for quantifying various sugars using an innovative bi-nanozyme made from a 2-dimensional Fe/Ce metal-organic framework (FeCe-BTC). The MOF showed excellent bifunctional peroxidase-oxidase activities, efficiently catalyzing luminol's chemiluminescence (CL) reaction. As a peroxidase-like nanozyme, FeCe-BTC could facilitate the dissociation of hydrogen peroxide (H2O2) into hydroxyl radicals, which then oxidize luminol. Additionally, it was also discovered that when reacting with H2O2, the MOF turns into a mixed-valence MOF, and acts as an oxidase nanozyme. This activity is caused by the generated Ce4+ ions in the structure of MOF that can directly oxidize luminol. The MOF was directly synthesized on the PAD and cascaded with specific natural enzymes to establish simple, rapid, and selective CL sensors for the measurement of different sugars. A cell phone was also used to record light intensities, which were then correlated to the analyte concentration. The designed PAD showed a wide linear range of 0.1-10 mM for glucose, fructose, and sucrose, with detection limits of 0.03, 0.04, and 0.04 mM, respectively. It showed satisfactory results in food and biological samples with recovery values ranging from 95.8 to 102.4 %, which makes it a promising candidate for point-of-care (POC) testing for food control and medicinal purposes.

The potential use of nanozyme in aging and age-related diseases

The effects of an increasingly elderly population are among the most far-reaching in 21st-century society. The growing healthcare expense is mainly attributable to the increased incidence of chronic illnesses that accompany longer life expectancies. Different ideas have been put up to explain aging, but it is widely accepted that oxidative damage to proteins, lipids, and nucleic acids contributes to the aging process. Increases in life expectancy in all contemporary industrialized cultures are accompanied by sharp increases in the prevalence of age-related diseases such as cardiovascular and neurological conditions, type 2 diabetes, osteoporosis, and cancer. Therefore, academic and public health authorities should prioritize the development of therapies to increase health span. Nanozyme (NZ)-like activity in nanomaterials has been identified as promising anti-aging nanomedicines. More than that, nanomaterials displaying catalytic activities have evolved as artificial enzymes with high structural stability, variable catalytic activity, and functional diversity for use in a wide range of biological settings, including those dealing with age-related disorders. Due to their inherent enzyme-mimicking qualities, enzymes have attracted significant interest in treating diseases associated with reactive oxygen species (ROS). The effects of NZs on aging and age-related disorders are summarized in this article. Finally, prospects and threats to enzyme research and use in aging and age-related disorders are offered.

Toward Sensitive and Reliable Immunoassays of Marine Biotoxins: From Rational Design to Food Analysis

Marine biotoxins are metabolites produced by algae that can accumulate in shellfish or fish and enter organisms through the food chain, posing a serious threat to biological health. Therefore, accurate and rapid detection is an urgent requirement for food safety. Although various detection methods, including the mouse bioassay, liquid chromatography-mass spectrometry, and cell detection methods, and protein phosphatase inhibition assays have been developed in the past decades, the current detection methods cannot fully meet these demands. Among these methods, the outstanding immunoassay virtues of high sensitivity, reliability, and low cost are highly advantageous for marine biotoxin detection in complex samples. In this work, we review the recent 5-year progress in marine biotoxin immunodetection technologies such as optical immunoassays, electrochemical immunoassays, and piezoelectric immunoassays. With the assistance of immunoassays, the detection of food-related marine biotoxins can be implemented for ensuring public health and preventing food poisoning. In addition, the immunodetection technique platforms including lateral flow chips and microfluidic chips are also discussed. We carefully investigate the advantages and disadvantages for each immunoassay, which are compared to demonstrate the guidance for selecting appropriate immunoassays and platforms for the detection of marine biotoxins. It is expected that this review will provide insights for the further development of immunoassays and promote the rapid progress and successful translation of advanced immunoassays with food safety detection.

Ultrasmall CuMn-His Nanozymes with Multienzyme Activity at Neutral pH: Construction of a Colorimetric Sensing Array for Biothiol Detection and Disease Identification

Biothiol assays offer vital insights into health assessment and facilitate the early detection of potential health issues, thereby enabling timely and effective interventions. In this study, we developed ultrasmall CuMn-Histidine (His) nanozymes with multiple enzymatic activities. CuMn-His enhanced peroxidase (POD)-like activity at neutral pH was achieved through hydrogen bonding and electrostatic effects. In addition, CuMn-His possesses laccase (LAC)-like and superoxide dismutase (SOD)-like activities at neutral pH. Based on three different enzyme mimetic activities of CuMn-His at neutral pH, the colorimetric sensing array without changing the buffer solution was successfully constructed. The array was successfully used for the identification of three biothiols, glutathione (GSH), cysteine (Cys), and homocysteine (Hcy). Subsequently, excellent application results were shown in complex serum and cellular level analyses. This study provides an innovative strategy for the development of ultrasmall bimetallic nanozymes with multiple enzymatic activities and the construction of colorimetric sensing arrays.

The Future of Nanotechnology-Driven Electrochemical and Electrical Point-of-Care Devices and Diagnostic Tests

Point-of-care (POC) devices have become rising stars in the biosensing field, aiming at prognosis and diagnosis of diseases with a positive impact on the patient but also on healthcare and social care systems. Putting the patient at the center of interest requires the implementation of noninvasive technologies for collecting biofluids and the development of wearable platforms with integrated artificial intelligence-based tools for improved analytical accuracy and wireless readout technologies. Many electrical and electrochemical transducer technologies have been proposed for POC-based sensing, but several necessitate further development before being widely deployable. This review focuses on recent innovations in electrochemical and electrical biosensors and their growth opportunities for nanotechnology-driven multidisciplinary approaches. With a focus on analytical aspects to pave the way for future electrical/electrochemical diagnostics tests, current limitations and drawbacks as well as directions for future developments are highlighted.

Sensitive, Semiquantitative, and Portable Nucleic Acid Detection of Rabies Virus Using a Personal Glucose Meter

Rabies is a zoonotic infection with the potential to infect all mammals and poses a significant threat to mortality. Although enzyme-linked immunosorbent tests and real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR) have been established for rabies virus (RABV) detection, they require skilled staff. Here, we introduce a personal glucose meter (PGM)-based nucleic acid (NA-PGM) detection method to diagnose RABV. This method ensures sensitive and convenient RABV diagnosis through hybridization of reverse transcription-recombinase aided amplification (RT-RAA) amplicons with probes labeled with sucrose-converting enzymes, reaching a detection level as low as 6.3 copies/μL equivalent to 12.26 copies. NA-PGM allows for the differentiation of RABV from other closely related viruses. In addition, NA-PGM showed excellent performance on 65 clinical samples with a 100% accuracy rate compared with the widely adopted RT-qPCR method. Thus, our developed NA-PGM method stands out as sensitive, semiquantitative, and portable for RABV detection, showcasing promise as a versatile platform for a wide range of pathogens.

Nanoenzymes: A Radiant Hope for the Early Diagnosis and Effective Treatment of Breast and Ovarian Cancers

Breast and ovarian cancers, despite having chemotherapy and surgical treatment, still have the lowest survival rate. Experimental stages using nanoenzymes/nanozymes for ovarian cancer diagnosis and treatment are being carried out, and correspondingly the current treatment approaches to treat breast cancer have a lot of adverse side effects, which is the reason why researchers and scientists are looking for new strategies with less side effects. Nanoenzymes have intrinsic enzyme-like activities and can reduce the shortcomings of naturally occurring enzymes due to the ease of storage, high stability, less expensive, and enhanced efficiency. In this review, we have discussed various ways in which nanoenzymes are being used to diagnose and treat breast and ovarian cancer. For breast cancer, nanoenzymes and their multi-enzymatic properties can control the level of reactive oxygen species (ROS) in cells or tissues, for example, oxidase (OXD) and peroxidase (POD) activity can be used to generate ROS, while catalase (CAT) or superoxide dismutase (SOD) activity can scavenge ROS. In the case of ovarian cancer, most commonly nanoceria is being investigated, and also when folic acid is combined with nanoceria there are additional advantages like inhibition of beta galactosidase. Nanocarriers are also used to deliver small interfering RNA that are effective in cancer treatment. Studies have shown that iron oxide nanoparticles are actively being used for drug delivery, similarly ferritin carriers are used for the delivery of nanozymes. Hypoxia is a major factor in ovarian cancer, therefore MnO2-based nanozymes are being used as a therapy. For cancer diagnosis and screening, nanozymes are being used in sonodynamic cancer therapy for cancer diagnosis and screening, whereas biomedical imaging and folic acid gold particles are also being used for image guided treatments. Nanozyme biosensors have been developed to detect ovarian cancer. This review article summarizes a detailed insight into breast and ovarian cancers in light of nanozymes-based diagnostic and therapeutic approaches.

An Au bipyramids@CuZn MOF core-shell nanozyme enables universal SERS and a colorimetric dual-model bioassay

In this study, a new type of gold nano-bipyramids@CuZn bimetallic organic framework (AuNBPs@CuZn MOF) nanozyme with high peroxidase (POD)-like activity and surface enhanced Raman scattering (SERS) activity was constructed with a special core-shell structure, which can catalyze the oxidation of TMB (colourless and Raman-inactive) into ox-TMB (blue and Raman-active). An AuNBPs@CuZn MOF-enabling universal SERS and colorimetric dual-model bioassay was thus developed for biomolecules with excellent performance, and has promising application prospects in the biosensing fields.

Bioinspired and Green Synthesis of Silver Nanoparticles for Medical Applications: A Green Perspective

Silver nanoparticles (AgNPs) possess unmatched chemical, biological, and physical properties that make them unique compounds as antimicrobial, antifungal, antiviral, and anticancer agents. With the increasing drug resistance, AgNPs serve as promising entities for targeted drug therapy against several bacterial, fungal, and viral components. In addition, AgNPs also serve as successful anticancer agents against several cancers, including breast, prostate, and lung cancers. Several works in recent years have been done towards the development of AgNPs by using plant extracts like flowers, leaves, bark, root, stem, and whole plant parts. The green method of AgNP synthesis thus has several advantages over chemical and physical methods, especially the low cost of synthesis, no toxic byproducts, eco-friendly production pathways, can be easily regenerated, and the bio-reducing potential of plant derived nanoparticles. Furthermore, AgNPs are biocompatible and do not harm normally functioning human or host cells. This review provides an exhaustive overview and potential of green synthesized AgNPs that can be used as antimicrobial, antifungal, antiviral, and anticancer agents. After a brief introduction, we discussed the recent studies on the development of AgNPs from different plant extracts, including leaf parts, seeds, flowers, stems, bark, root, and whole plants. In the following section, we highlighted the different therapeutic actions of AgNPs against various bacteria, fungi, viruses, and cancers, including breast, prostate, and lung cancers. We then highlighted the general mechanism of action of AgNPs. The advantages of the green synthesis method over chemical and physical methods were then discussed in the article. Finally, we concluded the review by providing future perspectives on this promising field in nanotechnology.

Integrating of analytical techniques with enzyme-mimicking nanomaterials for the fabrication of microfluidic systems for biomedical analysis

Bioanalysis faces challenges in achieving fast, reliable, and point-of-care (POC) determination methods for timely diagnosis and prognosis of diseases. POC devices often display lower sensitivity compared to laboratory-based methods, limiting their ability to quantify low concentrations of target analytes. To enhance sensitivity, the synthesis of new materials and improvement of the efficiency of the analytical strategies are necessary. Enzyme-mimicking materials have revolutionized the field of the fabrication of new high-throughput sensing devices. The integration of microfluidic chips with analytical techniques offers several benefits, such as easy miniaturization, need for low biological sample volume, etc., while also enhancing the sensitivity of the probe. The use enzyme-like nanomaterials in microfluidic systems can offer portable strategies for real-time and reliable detection of biological agents. Colorimetry and electrochemical methods are commonly utilized in the fabrication of nanozyme-based microfluidic systems. The review summarizes recent developments in enzyme-mimicking materials-integrated microfluidic analytical methods in biomedical analysis and discusses the current challenges, advantages, and potential future directions.

Ultrasensitive and Highly Selective Detection of Staphylococcus aureus at the Single-Cell Level Using Bacteria-Imprinted Polymer and Vancomycin-Conjugated MnO2 Nanozyme

Pathogenic bacterial infections, even at extremely low concentrations, pose significant threats to human health. However, the challenge persists in achieving high-sensitivity bacterial detection, particularly in complex samples. Herein, we present a novel sandwich-type electrochemical sensor utilizing bacteria-imprinted polymer (BIP) coupled with vancomycin-conjugated MnO2 nanozyme (Van@BSA-MnO2) for the ultrasensitive detection of pathogenic bacteria, exemplified by Staphylococcus aureus (S. aureus). The BIP, in situ prepared on the electrode surface, acts as a highly specific capture probe by replicating the surface features of S. aureus. Vancomycin (Van), known for its affinity to bacterial cell walls, is conjugated with a Bovine serum albumin (BSA)-templated MnO2 nanozyme through EDC/NHS chemistry. The resulting Van@BSA-MnO2 complex, serving as a detection probe, provides an efficient catalytic platform for signal amplification. Upon binding with the captured S. aureus, the Van@BSA-MnO2 complex catalyzes a substrate reaction, generating a current signal proportional to the target bacterial concentration. The sensor displays remarkable sensitivity, capable of detecting a single bacterial cell in a phosphate buffer solution. Even in complex milk matrices, it maintains outstanding performance, identifying S. aureus at concentrations as low as 10 CFU mL-1 without requiring intricate sample pretreatment. Moreover, the sensor demonstrates excellent selectivity, particularly in distinguishing target S. aureus from interfering bacteria of the same genus at concentrations 100-fold higher. This innovative method, employing entirely synthetic materials, provides a versatile and low-cost detection platform for Gram-positive bacteria. In comparison to existing nanozyme-based bacterial sensors with biological recognition materials, our assay offers distinct advantages, including enhanced sensitivity, ease of preparation, and cost-effectiveness, thereby holding significant promise for applications in food safety and environmental monitoring.

Single-Atom-Based Nanoenzyme in Tissue Repair

Since the discovery of ferromagnetic nanoparticles Fe3O4 that exhibit enzyme-like activity in 2007, the research on nanoenzymes has made significant progress. With the in-depth study of various nanoenzymes and the rapid development of related nanotechnology, nanoenzymes have emerged as a promising alternative to natural enzymes. Within nanozymes, there is a category of metal-based single-atom nanozymes that has been rapidly developed due to low cast, convenient preparation, long storage, less immunogenicity, and especially higher efficiency. More importantly, single-atom nanozymes possess the capacity to scavenge reactive oxygen species through various mechanisms, which is beneficial in the tissue repair process. Herein, this paper systemically highlights the types of metal single-atom nanozymes, their catalytic mechanisms, and their recent applications in tissue repair. The existing challenges are identified and the prospects of future research on nanozymes composed of metallic nanomaterials are proposed. We hope this review will illuminate the potential of single-atom nanozymes in tissue repair, encouraging their sequential clinical translation.

Metal oxide nanomaterials based electrochemical and optical biosensors for biomedical applications: Recent advances and future prospectives

The amalgamation of nanostructures with modern electrochemical and optical techniques gave rise to interesting devices, so-called biosensors. A biosensor is an analytical tool that incorporates various biomolecules with an appropriate physicochemical transducer. Over the past few years, metal oxide nanomaterials (MONMs) have significantly stimulated biosensing research due to their desired functionalities, versatile chemical stability, and low cost along with their unique optical, catalytic, electrical, and adsorption properties that provide an attractive platform for linking the biomolecules, for example, antibodies, nucleic acids, enzymes, and receptor proteins as sensing elements with the transducer for the detection of signals or signal amplifications. The signals to be measured are in direct proportionate to the concentration of the bioanalyte. Because of their simplicity, cost-effectiveness, portability, quick analysis, higher sensitivity, and selectivity against a broad range of biosamples, MONMs-based electrochemical and optical biosensing platforms are exhaustively explored as powerful early-diagnosis tools for point of care applications. Herein, we made a bibliometric analysis of past twenty years (2004-2023) on the application of MONMs as electrochemical and optical biosensing units using Web of Science database and the results of which clearly reveal the increasing number of publications since 2004. Geographical area distribution analysis of these publications shows that China tops the list followed by the United States of America and India. In this review, we first describe the electrochemical and optical properties of MONMs that are crucial for the creation of extremely stable, specific, and sensitive sensors with desirable characteristics. Then, the biomedical applications of MONMs-based bare and hybrid electrochemical and optical biosensing frameworks are highlighted in the light of recent literature. Finally, current limitations and future challenges in the field of biosensing technology are addressed.

Enhanced "Electronic Tongue" for Dental Bacterial Discrimination and Elimination Based on a DNA-Encoded Nanozyme Sensor Array

Bacterial infections are the second leading cause of death around the world, especially those caused by delayed treatment and misdiagnosis. Therefore, rapid discrimination and effective elimination of multiple bacteria are of great importance for improving the survival rate in clinic. Herein, a novel colorimetric sensor array for bacterial discrimination and elimination is constructed using programmable DNA-encoded iron oxide nanoparticles (IONPs) as sensing elements. Utilizing differential interactions of bacteria on DNA-encoded IONPs, 11 kinds of dental bacteria and 6 kinds of proteins have been successfully identified by linear discriminant analysis (LDA). Moreover, the developed sensing system also performs well in the quantitative determination of individual bacteria and identification of bacterial mixtures. More importantly, the practicability of this sensing strategy is further verified by precise differentiation of blind and artificial saliva samples. Furthermore, the sensor array is used for efficiently killing multiple bacteria, demonstrating great potential in clinical prophylaxis and therapy.

The Nanozyme Revolution: Enhancing the Performance of Medical Biosensing Platforms

Nanozymes represent a class of nanosized materials that exhibit innate catalytic properties similar to biological enzymes. The unique features of these materials have positioned them as promising candidates for applications in clinical sensing devices, specifically those employed at the point-of-care. They notably have found use as a means to amplify signals in nanosensor-based platforms and thereby improve sensor detection limits. Recent developments in the understanding of the fundamental chemistries underpinning these materials have enabled the development of highly effective nanozymes capable of sensing clinically relevant biomarkers at detection limits that compete with "gold-standard" techniques. However, there remain considerable hurdles that need to be overcome before these nanozyme-based sensors can be utilized in a platform ready for clinical use. An overview of the current understandings of nanozymes for disease diagnostics and biosensing applications and the unmet challenges that must be considered prior to their translation in clinical diagnostic tests is provided.

Bioinspired FeN5 Sites with Enhanced Peroxidase-like Activity Enable Colorimetric Sensing of Uranyl Ions in Seawater

Nanozymes with peroxidase (POD)-like activity have garnered significant attention due to their exceptional performance in colorimetric assays. However, nanozymes often possess oxidase (OD) and POD-like activity simultaneously, which affects the accuracy and sensitivity of the detection results. To address this issue, inspired by the catalytic pocket of natural POD, a single-atom nanozyme with FeN5 configuration is designed, exhibiting enhanced POD-like activity in comparison with a single-atom nanozyme with FeN4 configuration. The axial N atom in FeN5 highly mimics the amino acid residues in natural POD to optimize the electronic structure of the metal active center Fe, realizing the efficient activation of H2O2. In addition, in the presence of both H2O2 and O2, FeN5 enhances the activation of H2O2, effectively avoiding the interference of dissolved oxygen in colorimetric sensing. As a proof-of-concept application, a colorimetric detection platform for uranyl ions (UO22+) in seawater is successfully constructed, demonstrating satisfactory sensitivity and specificity.