Advances in Nanomaterial-Based Platforms to Combat COVID-19: Diagnostics, Preventions, Therapeutics, and Vaccine Developments

Potential usage of boron modified carbon nanodots as a marker candidate for coronavirus disease (COVID-19) antibody detection

The global outbreak of COVID-19 in December 2019 has highlighted rapid and accurate diagnostic tools for effective intervention. While the RT-PCR test offers 86 % sensitivity, uncertainties often require supplementary screening. This research investigates how carbon dots (CDs) can be utilized as markers for COVID-19 antibodies, taking advantage of their biocompatibility and low toxicity. CDs were synthesized using citric acid (CA) and APBA with boronic acid, enabling the detection of COVID-19 IgG antibodies with increased absorbance and fluorescence. Comprehensive analyses confirmed the successful synthesis of APBA-CDs, prompting further exploration of their impact on SARS-CoV-2 RNA. Increased absorbance levels were observed in categories K1, K2, and K3, attributed to the introduction of CDs into plasma, indicating effective binding of APBA-CDs to COVID-19 antibodies. In addition, the fluorescence tests consistently showed heightened levels across all categories, emphasizing the effective binding of APBA-CDs with COVID-19 antibodies, particularly in positive plasma samples. As a part of our analysis, we conducted a PCA test to validate the data, which revealed that APBA-CDs are specific to IgG+ antibodies. The results showed a sensitivity rate of 74 % and a specificity rate of 53 %, while, when tested for IgM antibodies, the sensitivity and specificity rates were 63 % and 27 %, respectively. These findings highlight the potential of APBA-CDs as a sensitive and specific marker for COVID-19 antibody detection, offering potential for diagnostic tool development.

Mechanistic Approach to Immunity and Immunotherapy of Alzheimer's Disease: A Review

Alzheimer's disease (AD) is a debilitating neurodegenerative condition characterized by progressive cognitive decline and memory loss, affecting millions of people worldwide. Traditional treatments, such as cholinesterase inhibitors and NMDA receptor antagonists, offer limited symptomatic relief without addressing the underlying disease mechanisms. These limitations have driven the development of more potent and effective therapies. Recent advances in immunotherapy present promising avenues for AD treatment. Immunotherapy strategies, including both active and passive approaches, harness the immune system to target and mitigate AD-related pathology. Active immunotherapy stimulates the patient's immune response to produce antibodies against AD-specific antigens, while passive immunotherapy involves administering preformed antibodies or immune cells that specifically target amyloid-β (Aβ) or tau proteins. Monoclonal antibodies, such as aducanumab and lecanemab, have shown potential in reducing Aβ plaques and slowing cognitive decline in clinical trials, despite challenges related to adverse immune responses and the need for precise targeting. This comprehensive review explores the role of the immune system in AD, evaluates the current successes and limitations of immunotherapeutic approaches, and discusses future directions for enhancing the treatment efficacy.

Influence of Physicochemical Properties of Iron Oxide Nanoparticles on Their Antibacterial Activity

The increasing occurrence of infectious diseases caused by antimicrobial resistance organisms urged the necessity to develop more potent, selective, and safe antimicrobial agents. The unique magnetic and tunable properties of iron oxide nanoparticles (IONPs) make them a promising candidate for different theragnostic applications, including antimicrobial agents. Though IONPs act as a nonspecific antimicrobial agent, their antimicrobial activities are directly or indirectly linked with their synthesis methods, synthesizing precursors, size, shapes, concentration, and surface modifications. Alteration of these parameters could accelerate or decelerate the production of reactive oxygen species (ROS). An increase in ROS role production disrupts bacterial cell walls, cell membranes, alters major biomolecules (e.g., lipids, proteins, nucleic acids), and affects metabolic processes (e.g., Krebs cycle, fatty acid synthesis, ATP synthesis, glycolysis, and mitophagy). In this review, we will investigate the antibacterial activity of bare and surface-modified IONPs and the influence of physiochemical parameters on their antibacterial activity. Additionally, we will report the potential mechanism of IONPs' action in driving this antimicrobial activity.

SARS-CoV-2 Neutralization by Cell Membrane-Coated Antifouling Nanoparticles

The global outbreak of the COVID-19 pandemic has indisputably wreaked havoc on societies worldwide, compelling the scientific community to seek urgently needed therapeutic agents with low-cost and low-side effect profiles. Numerous approaches have been investigated in the quest to prevent or treat COVID-19, but many of them exhibit unwelcome side effects, such as dysfunctional viral immune responses and inflammation. Herein, we present the preparation of solid natural human pulmonary alveolar epithelial cell (ATII) membrane-coated PLGA NPs (PLGA NPs@ATII-M), which demonstrate remarkable affinity and competitiveness to neutralize the SARS-CoV-2 S1 protein-coated NPs (SCMMA NPs-S1), which are employed as a surrogate for coronavirus particles. In addition, we first considered the antifouling properties of these types of NPs, and we found that this membrane-coated NP formulation boasts excellent antifouling capabilities, which serve to protect their neutralization properties out of shielding by protein coronas in blood circulation. Moreover, this formulation is easily prepared and stored with a low-cost profile and exhibits good specificity, high targeting efficiency, and potentially side effect avoiding, thus making it a highly promising candidate for COVID-19 treatment.

Local and systemic adverse effects of nanoparticles incorporated in dental materials- a critical review

Introduction

Nanotechnology is the science and engineering of nanoparticles whose dimensions range from 1 to 100 nm. Nanoparticles have special characteristics like increased surface area, high reactivity, and enhanced mechanical, thermal, and optical properties that make them attractive for use in dental applications. However, the use of nanoparticles in dental materials can have toxic effects on the human body. The objective of this paper is to discuss the toxic effects of various nanoparticles in dental materials, their adverse effect on human health, and measures to overcome such effects.

Objectives

Nanoparticles are used in the diagnosis, prevention, and treatment of oral diseases like dental caries, pulpo periodontal lesions, oral cancer, denture stomatitis, and candidiasis. Exposure to nanoparticles may occur to the dental professional, and the patient during procedures like restoration, finishing, and polishing. Such exposure to nanoparticles through inhalation, and ingestion causes toxic effects in the lungs, skin, brain, liver, and kidney. Proper risk assessment methods and preventive measures may help reduce these toxic effects to some extent.

Significance

Toxic effects of nanoparticles that are released during dental procedures, their route of exposure, and the concentration at which nanoparticles can induce toxic effects on the human body are discussed in detail in this review. The paper also aims to create awareness among dental professionals, students, and patients regarding nanoparticle exposure and its adverse effects, and methods to prevent and overcome these effects. Currently, it is ignored or taken lightly by the stakeholders and this review may throw light.

A novel Nb2C MXene based aptasensor for rapid and sensitive multi-mode detection of AFB1

Rapid and accurate on-site detection of aflatoxin B1 (AFB1) is of great significance for ensuring food safety. This work developed a dual mode aptasensor and a dual channel artificial neural network (ANN) intelligent sensor detection platform for simple and convenient quantitative detection of AFB1 in food. This sensor was prepared by encoding manganese ion (Mn2+) mediated surface concave niobium carbide MXene nanomaterials (Nb2C-MNs) using fluorescent group labeled aptamers (ssDNA-FAM). Mn2+-mediated Nb2C-MNs exhibited better peroxidase-like and fluorescence quenching properties. Moreover, ssDNA-FAM as a fluorescent probe for the sensor also significantly enhanced the enzyme activity of Nb2C-MNs. When AFB1 existed, ssDNA-FAM preferentially bonded to AFB1, resulting in fluorescence signal recovery and colorimetric signal weakening. Consequently, the multimodal biosensor could achieve fluorescence/colorimetric detection without the need for material and reagent replacement. In on-site detection, both ratio fluorescence and colorimetric signals could be collected using smartphones and analyzed and modeled on the developed ANN platform, achieving visual intelligent sensing. This multimodal biosensor had a detection line as low as 0.0950 ng/mL under optimal conditions, and also had the advantages of simple operation, fast and sensitive, and high specificity, which can meet the real-time on-site detection needs of AFB1 in remote areas.

A molecularly imprinted sensor for single-molecule detection of pesticide metabolite at the amol/L level sensitized by water-soluble luminol derivative encapsulated liposome via click reaction

A novel luminol derivative, 4-[(1,4-dioxo-1,2,3,4-tetrahydrophthalazin-5-yl)amino]-4-oxobut-2-enoic acid (ALD) with electrochemiluminescence intensity and stability characteristics similar to luminol, but higher solubility in near neutral solution, was designed and synthesized in this study. Using this derivative, a molecular imprinted electrochemiluminescence sensor (MIECLS) was prepared for the sensitive and selective determination of 2-amino-5-mercapto-1,3,4-thiadiazole (AMT), a metabolite of bismerthiazol, thiediazole copper, thiazole zinc, and other pesticides. The ALD probes encapsulated in liposomes are immobilized on the molecularly imprinted film by light-triggered click reaction, and the concurrent release of multiple probes allows for highly sensitive detection. In the AMT concentration range of 1.00 × 10-18 - 5.00 × 10-13 mol/L, the relation between ECL response and log AMT concentration is linear. With a detection limit of 5.25 × 10-19 mol/L (about 4 - 6 molecules in 10 μL of the sample), the sensor allows for high sensitivity analysis of ultra-trace amounts of small organic compounds. In general, the ECL-based single-molecule detection technique proposed herein might be a promising alternative to fluorescence single-molecule detection.

High-density Au nanoshells assembled onto Fe3O4 nanoclusters for integrated enrichment and photothermal/colorimetric dual-mode detection of SARS-CoV-2 nucleocapsid protein

Traditional lateral flow immunoassays (LFIA) suffer from insufficient sensitivity, difficulty for quantitation, and susceptibility to complex substrates, limiting their practical application. Herein, we developed a polyethylenimine (PEI)-mediated approach for assembling high-density Au nanoshells onto Fe3O4 nanoclusters (MagAushell) as LFIA labels for integrated enrichment and photothermal/colorimetric dual-mode detection of SARS-CoV-2 nucleocapsid protein (N protein). PEI layer served not only as "binders" to Fe3O4 nanoclusters and Au nanoshells, but also "barriers" to ambient environment. Thus, MagAushell not only combined magnetic and photothermal properties, but also showed good stability. With MagAushell, N protein was first separated and enriched from complex samples, and then loaded to the strip for detection. By observation of the color stripes, qualitative detection was performed with naked eye, and by measuring the temperature change under laser irradiation, quantification was attained free of sophisticated instruments. The introduction of Fe3O4 nanoclusters facilitated target purification and enrichment before LFIA, which greatly improved the anti-interference ability and increased the detection sensitivity by 2 orders compared with those without enrichment. Moreover, the high loading density of Au nanoshells on one Fe3O4 nanocluster enhanced the photothermal signal of the nanoprobe significantly, which could further increase the detection sensitivity. The photothermal detection limit reached 43.64 pg/mL which was 1000 times lower than colloidal gold strips. Moreover, this method was successfully applied to real samples, showing great application potential in practice. We envision that this LFIA could serve not only for SARS-CoV-2 detection but also as a general test platform for other biotargets in clinical samples.

Intranasal mRNA Delivery via Customized RNA-Polyplex Nanoparticles Enhancing Gene Expression through Photochemical Mechanisms

Achieving effective mRNA expression in vivo requires careful selection of an appropriate delivery vehicle and route of administration. Among the various routes of administration, intranasal administration has received considerable attention due to its ability to induce potent immune responses. In this context, we designed a specialized cationic polymer tailored for delivery of mRNA into the nasal cavity. These polymers are designed with varying degrees of substitution in different amine groups to allow for identification of the most suitable amine moiety for effective mRNA delivery. We also incorporated a photosensitizer within the polymer structure that can trigger the generation of reactive oxygen species when exposed to light. The synthesized cationic polymer is complexed with anionic mRNA to form a polyplex. Illuminating these polyplexes with laser light enhances their escape from intracellular endosomes, stimulating mRNA translocation into the cytoplasm, followed by increased mRNA expression at the cellular level. Through intranasal administration to C57BL/6 mice, it was confirmed that these photoactive polyplexes effectively induce mRNA expression and activate immune responses in vivo using photochemical effects. This innovative design of a photoactivated cationic polymer presents a promising and reliable strategy to achieve efficient intranasal mRNA delivery. This approach has potential applications in the development of mRNA-based vaccines for both prophylactic and therapeutic purposes.

CRISPR Cas12a-mediated amplification-free digital DNA assay improves the diagnosis and surveillance of Nasopharyngeal carcinoma

Sensitive and accurate cell-free plasma Epstein-Barr virus (EBV) DNA measurement is essential in the routine diagnosis, monitoring and treatment of Nasopharyngeal Carcinoma (NPC). This measurement in commercial and in-house assay are commonly based on real-time quantitative PCR (qPCR) method, which requires reference materials for standardization and lack quantitative precision due to amplification bias or cross-contamination. To address these issues, we developed a CRISPR/Cas12a-mediated amplification-free digital DNA assay, which targets the repetitive sequences of EBV DNA and utilizes the cis-cleavage activity of CRISPR-Cas12a prior to droplet generation. By this mean, more activated Cas12a-crRNA duplexes could be produced for subsequent target detection and counting, thus improving the performance in detecting low EBV DNA load. We demonstrated that it was more robust than conventional qPCR for detecting plasma EBV DNA in a case-control study of 208 participants, especially when the target concentrations were around the diagnostic cut-off value for NPC. More importantly, this assay allowed a more accurate diagnosis of early-stage NPC, with an area under the curve (AUC) of 0.9883 (versus 0.7682 for qPCR). Furthermore, its absolute quantification capability enabled dynamic monitoring of EBV load in NPC patients during initial diagnosis, treatment, and recurrence, thereby potentially improving disease management and prognosis. Taken together, our results demonstrate that this amplification-free digital assay has the potential to be a robust tool to improve the diagnosis and surveillance of NPC.

Therapeutic Copolymer from Salicylic Acid and l-Phenylalanine as a Nanosized Drug Carrier for Orthotopic Breast Cancer with Lung Metastasis

Nanoparticle (NP)-mediated drug delivery systems are promising for treating various diseases. However, clinical translation has been delayed by a variety of limitations, such as weak drug loading, nonspecific drug leakage, lack of bioactivity, and short blood circulation. These issues are in part due to the unsatisfactory function of biomaterials for nanocarriers. In addition, the synthesis procedures of drug carrier materials, especially polymers, were usually complicated and led to high cost. In this report, a bioactive copolymer of hydroxy acid and amino acid, poly(salicylic acid-co-phenylalanine) (PSP), was developed for the first time via a one-step rapid and facile synthesis strategy. The PSP could self-assemble into NPs (PSP-NPs) to co-load relatively hydrophilic sphingosine kinase 1 inhibitor (PF543 in HCl salt format) and highly hydrophobic paclitaxel (PTX) to form PF543/PTX@PSP-NPs with efficient dual drug loading. Encouragingly, PF543/PTX@PSP-NPs showed long blood circulation, good stability, and high tumor accumulation, leading to significantly enhanced therapeutic effects on breast cancer. Furthermore, PF543/PTX@PSP-NPs could additionally suppress the lung metastasis of breast cancer, and more importantly, the PSP-NPs themselves as therapeutic nanocarriers also showed an anti-breast cancer effect. With these combined advantages, this new polymer and corresponding NPs will provide valuable insights into the development of new functional polymers and nanomedicines for important diseases.

Highly efficient carbon supported Co-Ir nanozyme for the determination of total antioxidant capacity in foods

Nanozyme-based colorimetric assays have aroused extensive attention in biosensing due to quick response, low cost and simplicity. However, their practical applications are limited by the unsatisfactory stability and catalytic activity of nanozymes in complex detection environments. Herein, using the one-pot chemical vapor deposition method, we successfully prepare a highly efficient and stable carbon supported Co-Ir nanozyme (termed as Co-Ir/C nanozyme) for the determination of total antioxidant capacity (TAC) in food samples. The Co-Ir/C nanozyme shows excellent durability under extensive pH ranges, high temperature and high salt concentration due to the protection of carbon supporter. It can be recycled by simple magnetic separation, and its catalytic activity remains stable after long-term operation and storage. Taking full advantage of the superior peroxidase-like activity of Co-Ir/C nanozyme, it is used for colorimetric detection of ascorbic acid (or known as vitamin C), an important vitamin to adjust body's normal physiological function, with results showing higher sensitivity (detection limit of 0.27 μM) than most of the recently published works. Moreover, the determination of TAC in vitamin C tablets and fruits are further achieved, which are in good agreement with those of commercial colorimetric test kits. This study helps guide the rational preparation of versatile and highly stable nanozymes, and develops a robust TAC determination platform for future food quality monitoring.

Imaging intracellular metabolite and protein changes in live mammalian cells with bright fluorescent RNA-based genetically encoded sensors

Fluorescent RNA (FR)-based genetically encoded sensors have been engineered to detect various essential metabolites in living systems. However, the unfavorable characteristics of FR impede sensor applications. Here, we describe a strategy for converting Pepper fluorescent RNA into a series of fluorescent sensors to detect their cognate targets both in vitro and in live cells. Compared to previously developed FR-based sensors, Pepper-based sensors exhibited expanded emission of up to 620 nm and markedly improved cellular brightness, allowing robust and real-time monitoring of the pharmacologic-triggered dynamics changes in the intracellular level of S-adenosylmethionine (SAM) and the optogenetic manipulated protein translocation in live mammalian cells. Furthermore, signal amplification in fluorescence imaging of the target was achieved using the CRISPR-display strategy by incorporating a Pepper-based sensor into the sgRNA scaffold. Together, these results demonstrate that Pepper can be readily developed into high-performance FR-based sensors to detect various cellular targets.

MICaFVi: A Novel Magnetic Immuno-Capture Flow Virometry Nano-Based Diagnostic Tool for Detection of Coronaviruses

COVID-19 has resulted in a pandemic that aggravated the world's healthcare systems, economies, and education, and caused millions of global deaths. Until now, there has been no specific, reliable, and effective treatment to combat the virus and its variants. The current standard tedious PCR-based tests have limitations in terms of sensitivity, specificity, turnaround time, and false negative results. Thus, an alternative, rapid, accurate, and sensitive diagnostic tool that can detect viral particles, without the need for amplification or viral replication, is central to infectious disease surveillance. Here, we report MICaFVi (Magnetic Immuno-Capture Flow Virometry), a novel precise nano-biosensor diagnostic assay for coronavirus detection which combines the MNP-based immuno-capture of viruses for enrichment followed by flow-virometry analysis, enabling the sensitive detection of viral particles and pseudoviruses. As proof of concept, virus-mimicking spike-protein-coated silica particles (VM-SPs) were captured using anti-spike-antibody-conjugated MNPs (AS-MNPs) followed by detection using flow cytometry. Our results showed that MICaFVi can successfully detect viral MERS-CoV/SARS-CoV-2-mimicking particles as well as MERS-CoV pseudoviral particles (MERSpp) with high specificity and sensitivity, where a limit of detection (LOD) of 3.9 µg/mL (20 pmol/mL) was achieved. The proposed method has great potential for designing practical, specific, and point-of-care testing for rapid and sensitive diagnoses of coronavirus and other infectious diseases.

Hollow SnO2/CdS QDs/CdCO3 heterostructured nanocubes coupled with hollow PtPd/MnCo-CeO2 nanozyme-mediated synergistic amplification for ultrasensitive PEC immunoanalysis of lung cancer biomarker

Nowadays, lung cancer is one of the most dangerous cancers threatening human life all over the world. As a crucial biomarker, cytokeratin 19 fragment 21-1 (CYFRA 21-1) is extraordinary important for diagnosis of non-small cell lung cancer (NSCLC). In this work, we synthesized hollow SnO₂/CdS QDs/CdCO₃ heterostructured nanocubes with high and stable photocurrents, which applied to construction of a sandwich-typed photoelectrochemical (PEC) immunosensor for detection of CYFRA 21-1, integrated by in-situ catalytic precipitation strategy with home-built PtPd alloy anchored MnCo-CeO₂ (PtPd/MnCo-CeO₂) nanozyme for synergistic amplification. The interfacial electron transfer mechanism upon visible-light irradiation was investigated in details. Further, the PEC responses were seriously quenched by the specific immunoreaction and precipitation catalyzed by the PtPd/MnCo-CeO₂ nanozyme. The established biosensor showed a wider linear range of 0.001-200 ng mL^-1 and a lower limit of detection (LOD = 0.2 pg mL^-1, S/N = 3), coupled by exploring such analysis even in diluted human serum sample. This work opens a constructive avenue to develop ultrasensitive PEC sensing platforms for detecting diverse cancer biomarkers in clinic.

Cellular Metabolism: A Fundamental Component of Degeneration in the Nervous System

It is estimated that, at minimum, 500 million individuals suffer from cellular metabolic dysfunction, such as diabetes mellitus (DM), throughout the world. Even more concerning is the knowledge that metabolic disease is intimately tied to neurodegenerative disorders, affecting both the central and peripheral nervous systems as well as leading to dementia, the seventh leading cause of death. New and innovative therapeutic strategies that address cellular metabolism, apoptosis, autophagy, and pyroptosis, the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), growth factor signaling with erythropoietin (EPO), and risk factors such as the apolipoprotein E (APOE-ε4) gene and coronavirus disease 2019 (COVID-19) can offer valuable insights for the clinical care and treatment of neurodegenerative disorders impacted by cellular metabolic disease. Critical insight into and modulation of these complex pathways are required since mTOR signaling pathways, such as AMPK activation, can improve memory retention in Alzheimer's disease (AD) and DM, promote healthy aging, facilitate clearance of β-amyloid (Aß) and tau in the brain, and control inflammation, but also may lead to cognitive loss and long-COVID syndrome through mechanisms that can include oxidative stress, mitochondrial dysfunction, cytokine release, and APOE-ε4 if pathways such as autophagy and other mechanisms of programmed cell death are left unchecked.

Ultra-sensitive and specific detection of pathogenic nucleic acids using composite-excited hyperfine plasma spectroscopy combs sensitized by Au nanoarrays functionalized with 2D Ta2C-MXene

Accurate and rapid screening techniques on a population scale are crucial for preventing and managing epidemics like COVID-19. The standard gold test for nucleic acids in pathogenic infections is primarily the reverse transcription polymerase chain reaction (RT-PCR). However, this method is not suitable for widespread screening due to its reliance on large-scale equipment and time-consuming extraction and amplification processes. Here, we developed a collaborative system that combines high-load hybridization probes targeting N and OFR1a with Au NPs@Ta₂C-M modified gold-coated tilted fiber Bragg grating (TFBG) sensors to enable direct nucleic acid detection. Multiple activation sites of SARS-CoV-2 were saturable modified on the surface of a homogeneous arrayed AuNPs@Ta₂C-M/Au structure based on a segmental modification approach. The combination of hybrid probe synergy and composite polarisation response in the excitation structure results in highly specific hybridization analysis and excellent signal transduction of trace target sequences. The system demonstrates excellent trace specificity, with a limit of detection of 0.2 pg/mL, and achieves a rapid response time of 1.5 min for clinical samples without amplification. The results showed high agreement with the RT-PCR test (Kappa index = 1). And the gradient-based detection of 10-in-1 mixed samples exhibits high-intensity interference immunity and excellent trace identification. Therefore, the proposed synergistic detection platform has a good tendency to curb the global spread of epidemics such as COVID-19.

The SpACE-CCM: A facile and versatile cell culture medium-based biosensor for detection of SARS-CoV-2 spike-ACE2 interaction

The COVID-19 pandemic is an ongoing global public health threat. COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and binding of the SARS-CoV-2 spike to its receptor, angiotensin-converting enzyme 2 (ACE2), on host cells is critical for viral infection. Here, we developed a luminescent biosensor that readily detects interactions of the spike receptor-binding domain (RBD) and ACE2 in cell culture medium ('SpACE-CCM'), which was based on bimolecular complementation of the split nanoluciferase-fused spike RBD and ectodomain of ACE2 and further engineered to be efficiently secreted from cells by adding a heterologous secretory signal peptide (SSP). Screening of various SSPs identified 'interferon-α+alanine-aspartate' as the SSP that induced the highest activity. The SpACE-CCM biosensor was validated by observing a marked reduction of the activity caused by interaction-defective mutations or in the presence of neutralizing antibodies, recombinant decoy proteins, or peptides. Importantly, the SpACE-CCM biosensor responded well in assay-validating conditions compared with conventional cell lysate-based NanoLuc Binary Technology, indicating its advantage. We further demonstrated the biosensor's versatility by quantitatively detecting neutralizing activity in blood samples from COVID-19 patients and vaccinated individuals, discovering a small molecule interfering with the spike RBD-ACE2 interaction through high-throughput screening, and assessing the cross-reactivity of neutralizing antibodies against SARS-CoV-2 variants. Because the SpACE-CCM is a facile and rapid one-step reaction biosensor that aptly recapitulates the native spike-ACE2 interaction, it would be advantageous in many experimental and clinical applications associated with this interaction.

Modification with Conventional Surfactants to Improve a Lipid-Based Ionic-Liquid-Associated Transcutaneous Anticancer Vaccine

Transcutaneous vaccination is one of the successful, affordable, and patient-friendly advanced immunization approaches because of the presence of multiple immune-responsive cell types in the skin. However, in the absence of a preferable facilitator, the skin’s outer layer is a strong impediment to delivering biologically active foreign particles. Lipid-based biocompatible ionic-liquid-mediated nanodrug carriers represent an expedient and distinct strategy to permit transdermal drug delivery; with acceptable surfactants, the performance of drug formulations might be further enhanced. For this purpose, we formulated a lipid-based nanovaccine using a conventional (cationic/anionic/nonionic) surfactant loaded with an antigenic protein and immunomodulator in its core to promote drug delivery by penetrating the skin and boosting drug delivery and immunogenic cell activity. In a follow-up investigation, a freeze–dry emulsification process was used to prepare the nanovaccine, and its transdermal delivery, pharmacokinetic parameters, and ability to activate autoimmune cells in the tumor microenvironment were studied in a tumor-budding C57BL/6N mouse model. These analyses were performed using ELISA, nuclei and HE staining, flow cytometry, and other biological techniques. The immunomodulator-containing nanovaccine significantly (p < 0.001) increased transdermal drug delivery and anticancer immune responses (IgG, IgG1, IgG2, CD8+, CD207+, and CD103+ expression) without causing cellular or biological toxicity. Using a nanovaccination approach, it is possible to create a more targeted and efficient delivery system for cancer antigens, thereby stimulating a stronger immune response compared with conventional aqueous formulations. This might lead to more effective therapeutic and preventative outcomes for patients with cancer.

Virus-like particle-based nanocarriers as an emerging platform for drug delivery

New nanocarrier technologies are emerging, and they have great potential for improving drug delivery, targeting efficiency, and bioavailability. Virus-like particles (VLPs) are natural nanoparticles from animal and plant viruses and bacteriophages. Hence, VLPs present several great advantages, such as morphological uniformity, biocompatibility, reduced toxicity, and easy functionalisation. VLPs can deliver many active ingredients to the target tissue and have great potential as a nanocarrier to overcome the limitations associated with other nanoparticles. This review will focus primarily on the construction and applications of VLPs, particularly as a novel nanocarrier to deliver active ingredients. Herein, the main methods for the construction, purification, and characterisation of VLPs, as well as various VLP-based materials used in delivery systems are summarised. The biological distribution of VLPs in drug delivery, phagocyte-mediated clearance, and toxicity are also discussed.

MOF/COF heterostructure hybrid composite-based molecularly imprinted photoelectrochemical sensing platform for determination of dibutyl phthalate: A further expansion for MOF/COF application

A novel metal-organic framework (MOF)/covalent-organic framework (COF) heterostructure hybrid composite (NH₂-UiO-66/TpPa-1-COF) with excellent photoactivity was developed, which further acted as the photoelectrochemical sensitized layer of a molecularly imprinted photoelectrochemical (MIP-PEC) sensor for extremely sensitive and selective determination of dibutyl phthalate (DBP). The NH₂-UiO-66/TpPa-1-COF was synthesized using a simple one-step solvothermal method, which showed improved photocurrent response owing to heterojunction formation, favorable energy-band configuration and strong light absorption capacity. To improve the sensing performance, molecularly imprinted polymer (MIP) was developed by sol-gel polymerization method as the recognition component of PEC sensor. The specific binding of imprinting sites towards DBP could block the electron transfer, causing decreased photocurrent response of the MIP-PEC sensor. The MIP-PEC sensor showed a wide detection range from 0.1 nmol L^-1 to 100 μmol L^-1 with a limit of detection of 3.0 × 10^-11 mol L^-1 under optimal conditions. Meanwhile, the proposed MIP-PEC sensor showed good stability, selectivity, reproducibility, and applicability in real samples. This is the first attempt to apply MOF/COF heterostructure hybrid composite for MIP-PEC sensor construction, providing new insight into the potential applications of microporous crystalline framework heterostructure hybrid composite in the sensing field.

Harnessing enhanced CRISPR/Cas12a trans-cleavage activity with extended reporters and reductants for early diagnosis of Helicobacter pylori, the causative agent of peptic ulcers and stomach cancer

Developing rapid and non-invasive diagnostics for Helicobacter pylori (HP) is imperative to prevent associated diseases such as stomach gastritis, ulcers, and cancers. Owing to HP strain heterogeneity, not all HP-infected individuals incur side effects. Cytotoxin-associated gene A (CagA), and vacuolating cytotoxin A (VacA) genes predominantly drive HP pathogenicity. Therefore, diagnosing CagA and VacA genotypes could alert active infection and decide suitable therapeutics. We report an enhanced LbCas12a trans-cleavage activity with extended reporters and reductants (CEXTRAR) for early detection of HP. We demonstrate that extended ssDNA reporter acts as an excellent signal amplifier, making it a potential alternative substrate for LbCas12a collateral activity. Through a systematic investigation of various buffer components, we demonstrate that reductants improve LbCas12a trans-cleavage activity. Overall, our novel reporter and optimal buffer increased the trans-cleavage activity to an order of 16-fold, achieving picomolar sensitivity (171 pM) without target pre-amplification. Integrated with loop-mediated isothermal amplification (LAMP), CEXTRAR successfully attained attomolar sensitivity for HP detection using real-time fluorescence (43 and 96 aM), in-tube fluorescence readouts (430 and 960 aM), and lateral flow (4.3 and 9.6 aM) for CagA and VacA, respectively. We also demonstrate a rapid 2-min Triton X-100 lysis for clinical sample analysis, which could provide clinicians with actionable information for rapid diagnosis. CEXTRAR could potentially spot the ¹³C urea breath test false-negatives. For the first time, our study unveils an experimental outlook to manipulate reporters and reconsider precise cysteine substitution via protein engineering for Cas variants with enhanced catalytic activities for use in diagnostics and genetic engineering.

Targeted delivery and anticancer effects of Chrysin-loaded chitosan-folic acid coated solid lipid nanoparticles in pancreatic malignant cells

The aim of this survey was to load Chrysin (CHY) on solid lipid nanoparticles (SLNs) and decorate the nanoparticles with folate-bound chitosan to increase the effectiveness of the treatment. CHY-SCF-NPs were synthesized by homogenizing and sonication methods and characterized. FA binding and encapsulation efficiency (HPLC), antioxidant capacity (ABTS and DPPH), cell viability assay (MTT), programmed cell death analysis (fluorescence staining, flow cytometry, and qPCR), and angiogenesis (CAM and molecular analysis) assay were done for assessment of therapeutic efficiency of CHY-SCF-NPs. Increases in size and change in surface charge of CHY-SLNs (PS: 84.3 nm and ZP: -18 mV) were reported after coating with folate-bound chitosan (PS: 125 nm and ZP: +34.9 mV). CHY-SCF-NPs inhibited PANC, MCF-7, A2780, and HepG2 as malignant cells and HFF as normal cells with IC₅₀∼53, 55, 249, and >250 µg/mL, respectively. Also, CHY-SCF-NPs scavenged ABTS (IC₅₀: 123.73 µg/mL), and DPPH (IC₅₀: 108.7 µg/mL) free radicals and suppressed angiogenesis in the CAM and qPCR assays. Up-regulation of Bax and caspase 9 genes as well as the fluorescence staining and cell cycle results confirmed the pro-apoptotic properties of CHY-SCF-NPs. CHY-SCF-NPs can be considered a promising anti-cancer candidate for preclinical and clinical studies of pancreatic cancer.

Label-Free Analysis of Binding and Inhibition of SARS-Cov-19 Spike Proteins to ACE2 Receptor with ACE2-Derived Peptides by Surface Plasmon Resonance

SARS-CoV-2 has been shown to enter and infect human cells via interactions between spike protein (S glycoprotein) and angiotensin-converting enzyme 2 (ACE2). As such, it may be possible to suppress the infection of the virus via the blocking of this binding interaction through the use of specific peptides that can mimic the human ACE 2 peptidase domain (PD) α 1-helix. Herein, we report the use of competitive assays along with surface plasmon resonance (SPR) to investigate the effect of peptide sequence and length on spike protein inhibition. The characterization of these binding interactions helps us understand the mechanisms behind peptide-based viral blockage and develop SPR methodologies to quickly screen disease inhibitors. This work not only helps further our understanding of the important biological interactions involved in viral inhibition but will also aid in future studies that focus on the development of therapeutics and drug options. Two peptides of different sequence lengths, [30-42] and [22-44], based on the α 1-helix of ACE2 PD were selected for this fundamental investigation. In addition to characterizing their inhibitory behavior, we also identified the critical amino acid residues of the RBD/ACE2-derived peptides by combining experimental results and molecular docking modeling. While both investigated peptides were found to effectively block the RBD residues known to bind to ACE2 PD, our investigation showed that the shorter peptide was able to reach a maximal inhibition at lower concentrations. These inhibition results matched with molecular docking models and indicated that peptide length and composition are key in the development of an effective peptide for inhibiting biophysical interactions. The work presented here emphasizes the importance of inhibition screening and modeling, as longer peptides are not always more effective.

The Patrol Yeast: A new biosensor armed with antibody-receptor chimera detecting a range of toxic substances associated with food poisoning

Baker's yeast is an attractive host with established safety and stability characteristics. Many yeast-based biosensors have been developed, but transmembrane signal transduction has not been used to detect membrane-impermeable substances using antigen-antibody interactions. Therefore, we created Patrol Yeast, a novel yeast-based immunosensor of various targets, particularly toxic substances in food. A membrane-based yeast two-hybrid system using split-ubiquitin was successfully used to detect practically important concentration ranges of caffeine and aflatoxins using separated variable regions of an antibody. Moreover, enterohemorrhagic Escherichia coli O157 was detected using a specific single-chain antibody, in which Zymolyase was added to partially destroy the cell wall. The incorporation of secreted Cypridina luciferase reporter further simplified the signal detection procedures without cell lysis. The methodology is more cost-effective and faster than using mammalian cells. The ability to detect various targets renders Patrol Yeast a valuable tool for ensuring food and beverage safety and addressing other environmental and technological issues.

Structural, optical, magnetic, and enhanced antibacterial properties of hydrothermally synthesized Sm-incorporating α-MoO3 2D-layered nanoplates

In this study, we have synthesized pristine and [0.5,1.5, and 2.5] M% samarium (Sm)-incorporating α-MoO₃ 2D-layered nanoplates utilizing a facile hydrothermal process, and investigated the physical properties along with antibacterial effectiveness. X-ray diffraction (XRD) patterns confirmed the single-phase, stable orthorhombic polycrystalline structure of the as-prepared samples. The crystallite size, lattice strain, and dislocation density were measured using both Debye-Scherrer (D-S) and Williamson-Hall (W-H) techniques. Both pristine and Sm-incorporating α-MoO₃ samples showed two-dimensional (2D) layered nanoplate-type surface morphology, revealed by field emission scanning electron microscopy (FE-SEM) images. Energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Sm contents in the α-MoO₃ matrix. After Sm incorporation in α-MoO₃, the different functional groups as well as vibrational groups were observed by Fourier-transform infrared (FTIR) spectroscopy and Raman spectroscopy analyses, respectively. The optical band gaps were measured from UV-vis diffuse reflectance spectroscopy (DRS) by employing the Kubelka-Munk formula and interestingly it is found that the bandgap energy (E _g) gradually decreased from 2.96 to 2.83 eV with the increment of Sm content. When compared to pristine α-MoO₃, the Sm-incorporating samples experienced a steady improvement in room temperature ferromagnetic (RTFM) behavior as Sm content increased, as measured by hysteresis loops. The antibacterial activities of both samples were assessed against Gram-positive: Staphylococcus aureus (S. aureus), and Gram-negative: Escherichia coli (E. coli) and Salmonella enteritidis (S. enteritidis) bacteria by the agar well diffusion method and enhanced antibacterial activity was observed as the Sm concentration increased, compared to pristine nanoplates. The obtained results suggest that the synthesized Sm-incorporating α-MoO₃ 2D-layered nanoplate could be a potential antibacterial agent.

Galectin-3 binding protein stimulated IL-6 expression is impeded by antibody intervention in SARS-CoV-2 susceptible cell lines

COVID-19 is the global pandemic that affected our population in the past 2 years. Considerable research has been done to better understand the pathophysiology of this disease and to identify new therapeutic targets, especially for severe cases. Galectin-3 (Gal-3) is a receptor present at the surface of different cell types, namely epithelial and inflammatory cells, which has been described as a severity marker in COVID-19. The activation of Gal-3 through its binding protein (Gal-3BP) is directly linked to the production of pro-inflammatory cytokines that contribute for the cytokine storm (CS) observed in severe COVID-19 patients. Here, we show that D2, a recombinant fragment of the lectin-binding region of Gal-3BP was able to stimulate the expression of IL-6 in colon and lung epithelial cell lines in β-galactoside dependent manner. We further show that D2-induced IL-6 augmentation was reduced by the anti-Gal-3BP monoclonal antibody 1959. Our data confirm and extend prior findings of Gal-3BP mediated IL-6 induction, enlightening the potential of its antibody-mediated s blockage for the prevention and treatment of CS and severe disease in COVID-19 patients.

Human ACE2 Peptide-Attached Plasmonic-Magnetic Heterostructure for Magnetic Separation, Surface Enhanced Raman Spectroscopy Identification, and Inhibition of Different Variants of SARS-CoV-2 Infections

The emergence of Alpha, Beta, Gamma, Delta, and Omicron variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for several million deaths up to now. Because of the huge amount of vaccine escape mutations in the spike (S) protein for different variants, the design of material for combating SARS-CoV-2 is very important for our society. Herein, we report on the design of a human angiotensin converting enzyme 2 (ACE2) peptide-conjugated plasmonic-magnetic heterostructure, which has the capability for magnetic separation, identification via surface enhanced Raman spectroscopy (SERS), and inhibition of different variant SARS-CoV-2 infections. In this work, plasmonic-magnetic heterostructures were developed using the initial synthesis of polyethylenimine (PEI)-coated Fe3O4-based magnetic nanoparticles, and then gold nanoparticles (GNPs) were grown onto the surface of the magnetic nanoparticles. Experimental binding data between ACE2-conjugated plasmonic-magnetic heterostructures and spike-receptor-binding domain (RBD) show that the Omicron variant has maximum binding ability, and it follows Alpha < Beta < Gamma < Delta < Omicron. Our finding shows that, due to the high magnetic moment (specific magnetization 40 emu/g), bioconjugated heterostructures are capable of effective magnetic separation of pseudotyped SARS-CoV-2 bearing the Delta variant spike from an infected artificial nasal mucus fluid sample using a simple bar magnet. Experimental data show that due to the formation of huge "hot spots" in the presence of SARS-CoV-2, Raman intensity for the 4-aminothiolphenol (4-ATP) Raman reporter was enhanced sharply, which has been used for the identification of separated virus. Theoretical calculations using finite-difference time-domain (FDTD) simulation indicate that, due to the "hot spots" formation, a six orders of magnitude Raman enhancement can be observed. A concentration-dependent inhibition efficiency investigation using a HEK293T-human cell line indicates that ACE2 peptide-conjugated plasmonic-magnetic heterostructures have the capability of complete inhibition of entry of different variants and original SARS-CoV-2 pseudovirions into host cells.

Graphene-Based Field-Effect Transistor for Ultrasensitive Immunosensing of SARS-CoV-2 Spike S1 Antigen

Coronavirus disease (COVID-19) is an infectious disease that has posed a global health challenge caused by the SARS-CoV-2 virus. Early management and diagnosis of SARS-CoV-2 are crucial for the timely treatment, traceability, and reduction of viral spread. We have developed a rapid method using a Graphene-based Field-Effect Transistor (Gr-FET) for the ultrasensitive detection of SARS-CoV-2 Spike S1 antigen (S1-Ag). The in-house developed antispike S1 antibody (S1-Ab) was covalently immobilized on the surface of a carboxy functionalized graphene channel using carbodiimide chemistry. Ultraviolet-visible spectroscopy, Fourier-Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), Optical Microscopy, Raman Spectroscopy, Scanning Electron Microscopy (SEM), Enzyme-Linked Immunosorbent Assays (ELISA), and device stability studies were conducted to characterize the bioconjugation and fabrication process of Gr-FET. In addition, the electrical response of the device was evaluated by monitoring the change in resistance caused by Ag-Ab interaction in real time. For S1-Ag, our Gr-FET devices were tested in the range of 1 fM to 1 μM with a limit of detection of 10 fM in the standard buffer. The fabricated devices are highly sensitive, specific, and capable of detecting low levels of S1-Ag.