Stopping Membrane-Enveloped Viruses with Nanotechnology Strategies: Toward Antiviral Drug Development and Pandemic Preparedness

Advancements in Functional Nanomaterials Inspired by Viral Particles

Virus-like particles (VLPs) are nanostructures composed of one or more structural proteins, exhibiting stable and symmetrical structures. Their precise compositions and dimensions provide versatile opportunities for modifications, enhancing their functionality. Consequently, VLP-based nanomaterials have gained widespread adoption across diverse domains. This review focuses on three key aspects: the mechanisms of viral capsid protein self-assembly into VLPs, design methods for constructing multifunctional VLPs, and strategies for synthesizing multidimensional nanomaterials using VLPs. It provides a comprehensive overview of the advancements in virus-inspired functional nanomaterials, encompassing VLP assembly, functionalization, and the synthesis of multidimensional nanomaterials. Additionally, this review explores future directions, opportunities, and challenges in the field of VLP-based nanomaterials, aiming to shed light on potential advancements and prospects in this exciting area of research.

Design, synthesis, and molecular modeling studies of novel 2-quinolone-1,2,3-triazole-α-aminophosphonates hybrids as dual antiviral and antibacterial agents

With the aim to identify new antiviral agents with antibacterial properties, a series of 2-quinolone-1,2,3-triazole derivatives bearing α-aminophosphonates was synthesized and characterized by 1H NMR, 13C NMR, 31P NMR, single crystal XRD and HRMS analyses. These compounds were examined against five RNA viruses (YFV, ZIKV, CHIKV, EV71 and HRV) from three distinct families (Picornaviridae, Togaviridae and Flaviviridae) and four bacterial strains (S. aureus, E. feacalis, E. coli and P. aeruginosa). The α-aminophosphonates 4f, 4i, 4j, 4k, 4p and 4q recorded low IC50 values of 6.8-10.91 μM, along with elevated selectivity indices ranging from 2 to more than 3, particularly against YFV, CHIKV and HRV-B14. Besides, the synthesized compounds were generally more sensitive toward Gram-positive bacteria, with the majority of them displaying significant potency against E. feacalis. Specifically, an excellent anti-enterococcus activity was obtained by compound 4q with MIC and MBC values of 0.03 μmol/mL, which were 8.7 and 10 times greater than those of the reference drugs ampicillin and rifampicin, respectively. Also, compounds 4f, 4p and 4q showed potent anti-staphylococcal activity with MIC values varying between 0.11 and 0.13 μmol/mL, compared to 0.27 μmol/mL for ampicillin. The results from DFT and molecular docking simulations were in agreement with the biological assays, proving the binding capability of hybrids 4f, 4i, 4j, 4k, 4p and 4q with viral and bacterial target enzymes through hydrogen bonds and other non-covalent interactions. The in silico ADME/Tox prediction revealed that these molecules possess moderate to good drug-likeness and pharmacokinetic properties, with a minimal chance of causing liver toxicity or carcinogenic effects.

When Data Are Lacking: Physics-Based Inverse Design of Biopolymers Interacting with Complex, Fluid Phases

Biomolecular research traditionally revolves around comprehending the mechanisms through which peptides or proteins facilitate specific functions, often driven by their relevance to clinical ailments. This conventional approach assumes that unraveling mechanisms is a prerequisite for wielding control over functionality, which stands as the ultimate research goal. However, an alternative perspective emerges from physics-based inverse design, shifting the focus from mechanisms to the direct acquisition of functional control strategies. By embracing this methodology, we can uncover solutions that might not have direct parallels in natural systems, yet yield crucial insights into the isolated molecular elements dictating functionality. This provides a distinctive comprehension of the underlying mechanisms.In this context, we elucidate how physics-based inverse design, facilitated by evolutionary algorithms and coarse-grained molecular simulations, charts a promising course for innovating the reverse engineering of biopolymers interacting with intricate fluid phases such as lipid membranes and liquid protein phases. We introduce evolutionary molecular dynamics (Evo-MD) simulations, an approach that merges evolutionary algorithms with the Martini coarse-grained force field. This method directs the evolutionary process from random amino acid sequences toward peptides interacting with complex fluid phases such as biological lipid membranes, offering significant promises in the development of peptide-based sensors and drugs. This approach can be tailored to recognize or selectively target specific attributes such as membrane curvature, lipid composition, membrane phase (e.g., lipid rafts), and protein fluid phases. Although the resulting optimal solutions may not perfectly align with biological norms, physics-based inverse design excels at isolating relevant physicochemical principles and thermodynamic driving forces governing optimal biopolymer interaction within complex fluidic environments. In addition, we expound upon how physics-based evolution using the Evo-MD approach can be harnessed to extract the evolutionary optimization fingerprints of protein-lipid interactions from native proteins. Finally, we outline how such an approach is uniquely able to generate strategic training data for predictive neural network models that cover the whole relevant physicochemical domain. Exploring challenges, we address key considerations such as choosing a fitting fitness function to delineate the desired functionality. Additionally, we scrutinize assumptions tied to system setup, the targeted protein structure, and limitations posed by the utilized (coarse-grained) force fields and explore potential strategies for guiding evolution with limited experimental data. This discourse encapsulates the potential and remaining obstacles of physics-based inverse design, paving the way for an exciting frontier in biomolecular research.

Human antimicrobial peptide inactivation mechanism of enveloped viruses

HYPOTHESIS

Enveloped viruses are pivotal in causing various illnesses, including influenza and COVID-19. The antimicrobial peptide LL-37, a critical part of the human innate immune system, exhibits potential as an antiviral agent capable of thwarting these viral threats. Its mode of action involves versatile and non-specific interactions that culminate in dismantling the viral envelope, ultimately rendering the viruses inert. However, the exact mechanism of action is not yet understood.

EXPERIMENTS

Here, the mechanism of LL-37 triggered changes in the structure and function of an enveloped virus is investigated. The bacteriophage "Phi6" is used as a surrogate for pathogenic enveloped viruses. Small angle X-ray and neutron scattering combined with light scattering techniques demonstrate that LL-37 actively integrates into the virus's lipid envelope.

FINDINGS

LL-37 addition to Phi6 leads to curvature modification in the lipid bilayer, ultimately separating the envelope from the nucleocapsid. Additional biological assays confirm the loss of virus infectivity in the presence of LL-37, which coincides with the structural transformations. The results provide a fundamental understanding of the structure-activity relationship related to enveloped viruses. The knowledge of peptide-virus interactions can guide the design of future peptide-based antiviral drugs and therapies.

Glycerol Monolaurate Inhibits Wild-Type African Swine Fever Virus Infection in Porcine Macrophages

Naturally abundant antimicrobial lipids, such as fatty acids and monoglycerides, that disrupt membrane-enveloped viruses are promising mitigants to inhibit African swine fever virus (ASFV). Among mitigant candidates in this class, glycerol monolaurate (GML) has demonstrated particularly high antiviral activity against laboratory-adapted ASFV strains. However, there is an outstanding need to further determine the effects of GML on wild-type ASFV strains, which can have different virulence levels and sensitivities to membrane-disrupting compounds as compared to laboratory-adapted strains. Herein, we investigated the antiviral effects of GML on a highly virulent strain of a wild-type ASFV isolate (Armenia/07) in an in vitro porcine macrophage model. GML treatment caused a concentration-dependent reduction in viral infectivity, and there was a sharp transition between inactive and active GML concentrations. Low GML concentrations had negligible effect on viral infectivity, whereas sufficiently high GML concentrations caused a >99% decrease in viral infectivity. The concentration onset of antiviral activity matched the critical micelle concentration (CMC) value of GML, reinforcing that GML micelles play a critical role in enabling anti-ASFV activity. These findings validate that GML can potently inhibit wild-type ASFV infection of porcine macrophages and support a biophysical explanation to guide antimicrobial lipid performance optimization for pathogen mitigation applications.

Entangling of Peptide Nanofibers Reduces the Invasiveness of SARS-CoV-2

The viral spike (S) protein on the surface of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to angiotensin-converting enzyme 2 (ACE2) receptors on the host cells, facilitating its entry and infection. Here, functionalized nanofibers targeting the S protein with peptide sequences of IRQFFKK, WVHFYHK and NSGGSVH, which are screened from a high-throughput one-bead one-compound screening strategy, are designed and prepared. The flexible nanofibers support multiple binding sites and efficiently entangle SARS-CoV-2, forming a nanofibrous network that blocks the interaction between the S protein of SARS-CoV-2 and the ACE2 on host cells, and efficiently reduce the invasiveness of SARS-CoV-2. In summary, nanofibers entangling represents a smart nanomedicine for the prevention of SARS-CoV-2.

Dietary Supplementation of Aspirin Promotes Drosophila Defense against Viral Infection

Aspirin, also known as acetylsalicylic acid, is widely consumed as a pain reliever and an anti-inflammatory as well as anti-platelet agent. Recently, our studies using the animal model of Drosophila demonstrated that the dietary supplementation of aspirin renovates age-onset intestinal dysfunction and delays organismal aging. Nevertheless, it remains probable that aspirin plays functional roles in other biological activities, for instance antiviral defense reactions. Intriguingly, we observed that the replications of several types of viruses were drastically antagonized in Drosophila macrophage-like S2 cells with the addition of aspirin. Further in vivo experimental approaches illustrate that adult flies consuming aspirin harbor higher resistances to viral infections with respect to flies without aspirin treatment. Mechanistically, aspirin positively contributes to the Drosophila antiviral defense largely through mediating the STING (stimulator of interferon genes) but not the IMD (immune deficiency) signaling pathway. Collectively, our studies uncover a novel biological function of aspirin in modulating Drosophila antiviral immunity and provide theoretical bases for exploring new antiviral treatments in clinical trials.

Recent development in antiviral surfaces: Impact of topography and environmental conditions

The transmission of viruses is largely dependent on contact with contaminated virus-laden communal surfaces. While frequent surface disinfection and antiviral coating techniques are put forth by researchers as a plan of action to tackle transmission in dire situations like the Covid-19 pandemic caused by SARS-CoV-2 virus, these procedures are often laborious, time-consuming, cost-intensive, and toxic. Hence, surface topography-mediated antiviral surfaces have been gaining more attention in recent times. Although bioinspired hydrophobic antibacterial nanopatterned surfaces mimicking the natural sources is a very prevalent and successful strategy, the antiviral prospect of these surfaces is yet to be explored. Few recent studies have explored the potential of nanopatterned antiviral surfaces. In this review, we highlighted surface properties that have an impact on virus attachment and persistence, particularly focusing and emphasizing on the prospect of the nanotextured surface with enhanced properties to be used as antiviral surface. In addition, recent developments in surface nanopatterning techniques depending on the nano-scaled dimensions have been discussed. The impacts of environments and surface topology on virus inactivation have also been reviewed.

Physics-based generative model of curvature sensing peptides; distinguishing sensors from binders

Proteins can specifically bind to curved membranes through curvature-induced hydrophobic lipid packing defects. The chemical diversity among such curvature "sensors" challenges our understanding of how they differ from general membrane "binders" that bind without curvature selectivity. Here, we combine an evolutionary algorithm with coarse-grained molecular dynamics simulations (Evo-MD) to resolve the peptide sequences that optimally recognize the curvature of lipid membranes. We subsequently demonstrate how a synergy between Evo-MD and a neural network (NN) can enhance the identification and discovery of curvature sensing peptides and proteins. To this aim, we benchmark a physics-trained NN model against experimental data and show that we can correctly identify known sensors and binders. We illustrate that sensing and binding are phenomena that lie on the same thermodynamic continuum, with only subtle but explainable differences in membrane binding free energy, consistent with the serendipitous discovery of sensors.

A Facile Method to Coat Nanoparticles with Lipid Bilayer Membrane: Hybrid Silica Nanoparticles Disguised as Biomembrane Vesicles by Particle Penetration of Concentrated Lipid Layers

Natural membrane vesicles, including extracellular vesicles and enveloped viruses, participate in various events in vivo. To study and manipulate these events, biomembrane-coated nanoparticles inspired by natural membrane vesicles are developed. Herein, an efficient method is presented to prepare organic-inorganic hybrid materials in high yields that can accommodate various lipid compositions and particle sizes. To demonstrate this method, silica nanoparticles are passed through concentrated lipid layers prepared using density gradient centrifugation, followed by purification, to obtain lipid membrane-coated nanoparticles. Various lipids, including neutral, anionic, and cationic lipids, are used to prepare concentrated lipid layers. Single-particle analysis by imaging flow cytometry determines that silica nanoparticles are uniformly coated with a single lipid bilayer. Moreover, cellular uptake of silica nanoparticles is enhanced when covered with a lipid membrane containing cationic lipids. Finally, cell-free protein expression is applied to embed a membrane protein, namely the Spike protein of severe acute respiratory syndrome coronavirus 2, into the coating of the nanoparticles, with the correct orientation. Therefore, this method can be used to develop organic-inorganic hybrid nanomaterials with an inorganic core and a virus-like coating, serving as carriers for targeted delivery of cargos such as proteins, DNA, and drugs.

A DNA-Micropatterned Surface for Propagating Biomolecular Signals by Positional on-off Assembly of Catalytic Nanocompartments

Signal transduction is pivotal for the transfer of information between and within living cells. The composition and spatial organization of specified compartments are key to propagating soluble signals. Here, a high-throughput platform mimicking multistep signal transduction which is based on a geometrically defined array of immobilized catalytic nanocompartments (CNCs) that consist of distinct polymeric nanoassemblies encapsulating enzymes and DNA or enzymes alone is presented. The dual role of single entities or tandem CNCs in providing confined but communicating spaces for complex metabolic reactions and in protecting encapsulated compounds from denaturation is explored. To support a controlled spatial organization of CNCs, CNCs are patterned by means of DNA hybridization to a microprinted glass surface. Specifically, CNC-functionalized DNA microarrays are produced where individual reaction compartments are kept in close proximity by a distinct geometrical arrangement to promote effective communication. Besides a remarkable versatility and robustness, the most prominent feature of this platform is the reversibility of DNA-mediated CNC-anchoring which renders it reusable. Micropatterns of polymer-based nanocompartment assemblies offer an ideal scaffold for the development of the next generation responsive and communicative soft-matter analytical devices for applications in catalysis and medicine.

Affinity Exploration of SARS-CoV-2 RBD Variants to mAb-Functionalized Plasmonic Metasurfaces for Label-Free Immunoassay Boosting

Plasmonic metasurfaces (PMs) functionalized with the monoclonal antibody (mAb) are promising biophotonic sensors for biomolecular interaction analysis and convenient immunoassay of various biomarkers, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. Previous PM biosensing suffers from the slow affinity detection rate and lack of sufficient immunoassay studies on various SARS-CoV-2 variants. Here, we develop a high-efficiency affinity testing method based on label-free PM sensors with mAbs and demonstrate their binding characteristics to 12 spike receptor binding domain (RBD) variants of SARS-CoV-2. In addition to the research of plasmonic near-field influence on surface biomolecule sensing, we provide a comprehensive report about the Langmuir binding equilibrium of molecular kinetics between 12 SARS-CoV-2 RBD variants and mAb-functionalized PMs, which plays a crucial role in label-free immunosensing. A high-affinity mAb can be combined with the highly sensitive propagating plasmonic mode to boost the detection of SARS-CoV-2 variants. Owing to a better understanding of molecular dynamics on PMs, we develop an ultrasensitive biosensor of the SARS-CoV-2 Omicron variant. The experiments show great distinguishment of P < 0.0001 from respiratory diseases induced by other viruses, and the limit of detection is 2 orders smaller than the commercial colloidal gold immunoassay. Our study shows the label-free biosensing by low-cost wafer-scale PMs, which will provide essential information on biomolecular interaction and facilitate high-precision point-of-care testing for emerging SARS-CoV-2 variants in the future.

Cell-Free Synthesis Goes Electric: Dual Optical and Electronic Biosensor via Direct Channel Integration into a Supported Membrane Electrode

Assembling transmembrane proteins on organic electronic materials is one promising approach to couple biological functions to electrical readouts. A biosensing device produced in such a way would enable both the monitoring and regulation of physiological processes and the development of new analytical tools to identify drug targets and new protein functionalities. While transmembrane proteins can be interfaced with bioelectronics through supported lipid bilayers (SLBs), incorporating functional and oriented transmembrane proteins into these structures remains challenging. Here, we demonstrate that cell-free expression systems allow for the one-step integration of an ion channel into SLBs assembled on an organic conducting polymer, poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS). Using the large conductance mechanosensitive channel (MscL) as a model ion channel, we demonstrate that MscL adopts the correct orientation, remains mobile in the SLB, and is active on the polyelectrolyte surface using optical and electrical readouts. This work serves as an important illustration of a rapidly assembled bioelectronic platform with a diverse array of downstream applications, including electrochemical sensing, physiological regulation, and screening of transmembrane protein modulators.

Lipid Membrane Interface Viewpoint: From Viral Entry to Antiviral and Vaccine Development

Membrane-enveloped viruses are responsible for most viral pandemics in history, and more effort is needed to advance broadly applicable countermeasures to mitigate the impact of future outbreaks. In this Perspective, we discuss how biosensing techniques associated with lipid model membrane platforms are contributing to improving our mechanistic knowledge of membrane fusion and destabilization that is closely linked to viral entry as well as vaccine and antiviral drug development. A key benefit of these platforms is the simplicity of interpreting the results which can be complemented by other techniques to decipher more complicated biological observations and evaluate the biophysical functionalities that can be correlated to biological activities. Then, we introduce exciting application examples of membrane-targeting antivirals that have been refined over time and will continue to improve based on biophysical insights. Two ways to abrogate the function of viral membranes are introduced here: (1) selective disruption of the viral membrane structure and (2) alteration of the membrane component. While both methods are suitable for broadly useful antivirals, the latter also has the potential to produce an inactivated vaccine. Collectively, we emphasize how biosensing tools based on membrane interfacial science can provide valuable information that could be translated into biomedicines and improve their selectivity and performance.

Molekulare Pinzetten als Breitbandinhibitor viraler Infektionen

The SARS-CoV-2 pandemic once again highlighted the constant threat posed by viruses. Specific therapeutics are highly warranted, but their development is time consuming and cost intensive. Broad-spectrum antivirals provide a promising option for fast application to treat circulating or newly emerged viruses. Here, we introduce molecular tweezers as broad-spectrum antivirals, which abrogate viral infection by directly targeting the viral membrane. Furthermore, we discuss the current stage of tweezer development to fight SARS-CoV-2 and other respiratory viruses.

Nanotechnology-Driven Delivery Systems in Inoculation Therapies

Nanotechnology and genomics are the newest allies of inoculation design. In recent years, nucleic acids have been targeted as sources of therapeutics to stimulate immune responses, to both fight disease and create memory to trigger further responses to threat. A myriad of promising findings in cancer research and virology has been reported in the current literature. Nanosystems are demonstrating their capabilities as efficient carriers, improving the efficacy of drug delivery, including nucleic acids as therapeutics, at focal sites, in living systems. This chapter approaches major elements involved in the successful use of nanotechnology as delivery platforms to optimise the efficacy of nucleic acids-driven therapeutics, particularly mRNA vectors as coding engines for targeted viral proteins. Latest findings in nanotechnological design are highlighted, key discoveries associated with the success of nanodelivery platforms are presented, and key characteristics of nanodelivery systems in nucleic acids-based vaccine technology are discussed, to illustrate their distinct advantages and disadvantages.

Strong anti-viral nano biocide based on Ag/ZnO modified by amodiaquine as an antibacterial and antiviral composite

In this paper, we synthesized Ag/ZnO composite colloidal nanoparticles and the surface of nanoparticles was improved by amodiaquine ligand. The synthesized nanoparticles were characterized using the XRD diffraction pattern, FT-IR Spectroscopy, TEM image, and UV-Vis spectroscopy. The antibacterial, antifungal, and antiviral effects of the synthesized colloid were examined on E.coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus hirae bacteria, and Candida Albicans and form spore aspergillus fungi, also influenza, herpes simplex, and covid 19 viruses. The results indicate more than 7 log removal of the bacteria, fungi, and viruses by synthesized colloid with a concentration of 15 μg/L (Ag)/50 µg/ml (ZnO). This removal for covid 19 virus is from 3.2 × 10⁸ numbers to 21 viruses within 30 s. Also, irritation and toxicity tests of the synthesized colloid show harmless effects on human cells and tissues. These colloidal nanoparticles were used as mouthwash solution and their clinical tests were done on 500 people infected by the coronavirus. The results indicate that by washing their mouth and nose three times on day all patients got healthy at different times depending on the depth of the disease. Almost all people with no signs of infection and using this solution as a mouthwash didn't infect by the virus during the study.

State-of-art high-performance Nano-systems for mutated coronavirus infection management: From Lab to Clinic

The emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants made emerging novel coronavirus diseases (COVID-19) pandemic/endemic/or both more severe and difficult to manage due to increased worry about the efficacy and efficiency of present preventative, therapeutic, and sensing measures. To deal with these unexpected circumstances, the development of novel nano-systems with tuneable optical, electrical, magnetic, and morphological properties can lead to novel research needed for (1) COVID-19 infection (anti-microbial systems against SARS-CoV-2), (2) early detection of mutated SARS-CoV-2, and (3) targeted delivery of therapeutics using nano-systems, i.e., nanomedicine. However, there is a knowledge gap in understanding all these nano-biotechnology potentials for managing mutated SARS-CoV-2 on a single platform. To bring up the aspects of nanotechnology to tackle SARS-CoV-2 variants related COVID-19 pandemic, this article emphasizes improvements in the high-performance of nano-systems to combat SARS-CoV-2 strains/variants with a goal of managing COVID-19 infection via trapping, eradication, detection/sensing, and treatment of virus. The potential of state-of-the-art nano-assisted approaches has been demonstrated as an efficient drug delivery systems, viral disinfectants, vaccine productive cargos, anti-viral activity, and biosensors suitable for point-of-care (POC) diagnostics. Furthermore, the process linked with the efficacy of nanosystems to neutralize and eliminate SARS-CoV-2 is extensively highligthed in this report. The challenges and opportunities associated with managing COVID-19 using nanotechnology as part of regulations are also well-covered. The outcomes of this review will help researchers to design, investigate, and develop an appropriate nano system to manage COVID-19 infection, with a focus on the detection and eradication of SARS-CoV-2 and its variants. This article is unique in that it discusses every aspect of high-performance nanotechnology for ideal COVID pandemic management.

Antimicrobial monoglycerides for swine and poultry applications

The development of natural, broadly acting antimicrobial solutions to combat viral and bacterial pathogens is a high priority for the livestock industry. Herein, we cover the latest progress in utilizing lipid-based monoglycerides as feed additives to address some of the biggest challenges in animal agriculture. The current industry needs for effective antimicrobial strategies are introduced before discussing why medium-chain monoglycerides are a promising solution due to attractive molecular features and biological functions. We then critically analyze recent application examples in which case monoglycerides demonstrated superior activity to prevent feed transmission of viruses in swine and to mitigate bacterial infections in poultry along with gut microbiome modulation capabilities. Future innovation strategies are also suggested to expand the range of application possibilities and to enable new monoglyceride delivery options.

Nanotechnology-based strategies against SARS-CoV-2 variants

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has already infected more than 500 million people globally (as of May 2022), creating the coronavirus disease 2019 (COVID-19) pandemic. Nanotechnology has played a pivotal role in the fight against SARS-CoV-2 in various aspects, with the successful development of the two highly effective nanotechnology-based messenger RNA vaccines being the most profound. Despite the remarkable efficacy of mRNA vaccines against the original SARS-CoV-2 strain, hopes for quickly ending this pandemic have been dampened by the emerging SARS-CoV-2 variants, which have brought several new pandemic waves. Thus, novel strategies should be proposed to tackle the crisis presented by existing and emerging SARS-CoV-2 variants. Here, we discuss the SARS-CoV-2 variants from biological and immunological perspectives, and the rational design and development of novel and potential nanotechnology-based strategies to combat existing and possible future SARS-CoV-2 variants. The lessons learnt and design strategies developed from this battle against SARS-CoV-2 variants could also inspire innovation in the development of nanotechnology-based strategies for tackling other global infectious diseases and their future variants.

Advanced Molecular Tweezers with Lipid Anchors against SARS-CoV-2 and Other Respiratory Viruses

The COVID-19 pandemic caused by SARS-CoV-2 presents a global health emergency. Therapeutic options against SARS-CoV-2 are still very limited but urgently required. Molecular tweezers are supramolecular agents that destabilize the envelope of viruses resulting in a loss of viral infectivity. Here, we show that first-generation tweezers, CLR01 and CLR05, disrupt the SARS-CoV-2 envelope and abrogate viral infectivity. To increase the antiviral activity, a series of 34 advanced molecular tweezers were synthesized by insertion of aliphatic or aromatic ester groups on the phosphate moieties of the parent molecule CLR01. A structure-activity relationship study enabled the identification of tweezers with a markedly enhanced ability to destroy lipid bilayers and to suppress SARS-CoV-2 infection. Selected tweezer derivatives retain activity in airway mucus and inactivate the SARS-CoV-2 wildtype and variants of concern as well as respiratory syncytial, influenza, and measles viruses. Moreover, inhibitory activity of advanced tweezers against respiratory syncytial virus and SARS-CoV-2 was confirmed in mice. Thus, potentiated tweezers are broad-spectrum antiviral agents with great prospects for clinical development to combat highly pathogenic viruses.

Metal and metal oxide-based antiviral nanoparticles: Properties, mechanisms of action, and applications

Certain types of metal-based nanoparticles are effective antiviral agents when used in their original form ("bare") or after their surfaces have been functionalized ("modified"), including those comprised of metals (e.g., silver) and metal oxides (e.g., zinc oxide, titanium dioxide, or iron dioxide). These nanoparticles can be prepared with different sizes, morphologies, surface chemistries, and charges, which leads to different antiviral activities. They can be used as aqueous dispersions or incorporated into composite materials, such as coatings or packaging materials. In this review, we provide an overview of the design, preparation, and characterization of metal-based nanoparticles. We then discuss their potential mechanisms of action against various kinds of viruses. Finally, the applications of some of the most common metal and metal oxide nanoparticles are discussed, including those fabricated from silver, zinc oxide, iron oxide, and titanium dioxide. In general, the major antiviral mechanisms of metal and metal oxide nanoparticles have been observed to be 1) attachment of nanoparticles to surface moieties of viral particles like spike glycoproteins, that disrupt viral attachment and uncoating in host cells; 2) generation of reactive oxygen species (ROS) that denature viral macromolecules such as nucleic acids, capsid proteins, and/or lipid envelopes; and 3) inactivation of viral glycoproteins by the disruption of the disulfide bonds of viral proteins. Several physicochemical properties of metal and metal oxide nanoparticles including size, shape, zeta potential, stability in physiological conditions, surface modification, and porosity can all impact the antiviral efficacy of the nanoparticles.

Bomidin: An Optimized Antimicrobial Peptide With Broad Antiviral Activity Against Enveloped Viruses

The rapid evolution of highly infectious pathogens is a major threat to global public health. In the front line of defense against bacteria, fungi, and viruses, antimicrobial peptides (AMPs) are naturally produced by all living organisms and offer new possibilities for next-generation antibiotic development. However, the low yields and difficulties in the extraction and purification of AMPs have hindered their industry and scientific research applications. To overcome these barriers, we enabled high expression of bomidin, a commercial recombinant AMP based upon bovine myeloid antimicrobial peptide-27. This novel AMP, which can be expressed in Escherichia coli by adding methionine to the bomidin sequence, can be produced in bulk and is more biologically active than chemically synthesized AMPs. We verified the function of bomidin against a variety of bacteria and enveloped viruses, including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), herpes simplex virus (HSV), dengue virus (DENV), and chikungunya virus (CHIKV). Furthermore, based on the molecular modeling of bomidin and membrane lipids, we elucidated the possible mechanism by which bomidin disrupts bacterial and viral membranes. Thus, we obtained a novel AMP with an optimized, efficient heterologous expression system for potential therapeutic application against a wide range of life-threatening pathogens.

A Gradient pH-Sensitive Polymer-Based Antiviral Strategy via Viroporin-Induced Membrane Acidification

Lipid-membrane-targeting strategies hold great promise to develop broad-spectrum antivirals. However, it remains a big challenge to identify novel membrane-based targets of viruses and virus-infected cells for development of precision targeted approaches. Here, it is discovered that viroporins, viral-encoded ion channels, which have been reported to mediate release of hydrogen ions, trigger membrane acidification of virus-infected cells. Through development of a fine-scale library of gradient pH-sensitive (GPS) polymeric nanoprobes, the cellular membrane pH transitions are measured from pH 6.8-7.1 (uninfection) to pH 6.5-6.8 (virus-infection). In response to the subtle pH alterations, the GPS polymer with sharp response at pH 6.8 (GPS_6.8 ) selectively binds to virus-infected cell membranes or the viral envelope, and even completely disrupts the viral envelope. Accordingly, GPS_6.8 treatment exerts suppressive effects on a wide variety of viruses including SARS-CoV-2 through triggering viral-envelope lysis rather than affecting immune pathway or viability of host cells. Murine viral-infection models exhibit that supplementation of GPS_6.8 decreases viral titers and ameliorates inflammatory damage. Thus, the gradient pH-sensitive nanotechnology offers a promising strategy for accurate detection of biological pH environments and robust interference with viruses.

Development of antiviral carbon quantum dots that target the Japanese encephalitis virus envelope protein

Japanese encephalitis is a mosquito-borne disease caused by the Japanese encephalitis virus (JEV) that is prevalent in Asia and the Western Pacific. Currently, there is no effective treatment for Japanese encephalitis. Curcumin (Cur) is a compound extracted from the roots of Curcuma longa, and many studies have reported its antiviral and anti-inflammatory activities. However, the high cytotoxicity and very low solubility of Cur limit its biomedical applications. In this study, Cur carbon quantum dots (Cur-CQDs) were synthesized by mild pyrolysis-induced polymerization and carbonization, leading to higher water solubility and lower cytotoxicity, as well as superior antiviral activity against JEV infection. We found that Cur-CQDs effectively bound to the E protein of JEV, preventing viral entry into the host cells. In addition, after continued treatment of JEV with Cur-CQDs, a mutant strain of JEV was evolved that did not support binding of Cur-CQDs to the JEV envelope. Using transmission electron microscopy, biolayer interferometry, and molecular docking analysis, we revealed that the S123R and K312R mutations in the E protein play a key role in binding Cur-CQDs. The S123 and K312 residues are located in structural domains II and III of the E protein, respectively, and are responsible for binding to receptors on and fusing with the cell membrane. Taken together, our results suggest that the E protein of flaviviruses represents a potential target for the development of CQD-based inhibitors to prevent or treat viral infections.

Effect of Membrane Curvature Nanoarchitectonics on Membrane-Disruptive Interactions of Antimicrobial Lipids and Surfactants

Single-chain lipid amphiphiles such as fatty acids and monoglycerides along with structurally related surfactants have received significant attention as membrane-disrupting antimicrobials to inhibit bacteria and viruses. Such promise has motivated deeper exploration of how these compounds disrupt phospholipid membranes, and the membrane-mimicking, supported lipid bilayer (SLB) platform has provided a useful model system to evaluate corresponding mechanisms of action and potency levels. Even so, it remains largely unknown how biologically relevant membrane properties, such as sub-100 nm membrane curvature, might affect these membrane-disruptive interactions, especially from a nanoarchitectonics perspective. Herein, using the quartz crystal microbalance-dissipation (QCM-D) technique, we fabricated intact vesicle adlayers composed of different-size vesicles (70 or 120 nm diameter) with varying degrees of membrane curvature on a titanium oxide surface and tracked changes in vesicle adlayer properties upon adding lauric acid (LA), glycerol monolaurate (GML), or sodium dodecyl sulfate (SDS). Above their critical micelle concentration (CMC) values, LA and GML caused QCM-D measurement shifts associated with tubule- and bud-like formation, respectively, and both compounds interacted similarly with small (high curvature) and large (low curvature) vesicles. In marked contrast, SDS exhibited distinct interactions with small and large vesicles. For large vesicles, SDS caused nearly complete membrane solubilization in a CMC-independent manner, whereas SDS was largely ineffective at solubilizing small vesicles at all tested concentrations. We rationalize these experimental observations by taking into account the interplay of the headgroup properties of LA, GML, and SDS and curvature-induced membrane geometry, and our findings demonstrate that membrane curvature nanoarchitectonics can strongly influence the membrane interaction profiles of antimicrobial lipids and surfactants.

Antibacterial and antiviral high-performance nanosystems to mitigate new SARS-CoV-2 variants of concern

The increased severity of the COVID-19 infection due to new SARS-CoV-2 variants has resonated pandemic impact which made health experts to re-evaluate the effectiveness of pandemic management strategies. This becomes critical owing to the infection in large population and shortcomings in the existing global healthcare system worldwide. The designing of high-performance nanosystems (NS) with tunable performances seems to be the most efficient method to tackle infectious SARS-CoV-2 variants including recently emerged omicron mutation. In this direction, experts projects the versatile functionalized NS and their capabilities to mitigate SARS-CoV-2 propagation pathways by sensitization, antipathogenicity, photocatalysis, photothermal effects, immune response, developing efficient diagnostics assays or associated, selective biomarkers detection, and targeted drug delivery systems. To achieve these tasks, this opinion article project the importance of the fabrication of nano-enabled protective gear, masks, gloves, sheets, filtration units, nano-emulsified disinfectants, antiviral/bacterial paints, and therangostics to facilitate quarantine strategies via protection, detection, and treatment needed to manage COVID-19 pandemic in personalized manners. These functional protective high-performance antibacterial and antiviral NS can efficiently tackle the SARS-CoV-2 variants transmission through respiratory fluids and pollutants within water droplets, aerosols, air, and particulates along with their severe infection via neutralizing or eradicating the virus.

Inhibitory effect and mechanism of gelatin stabilized ferrous sulfide nanoparticles on porcine reproductive and respiratory syndrome virus

Background

The infection and spread of porcine reproductive and respiratory syndrome virus (PRRSV) pose a serious threat to the global pig industry, and inhibiting the viral infection process is a promising treatment strategy. Nanomaterials can interact with viruses and have attracted much attention due to their large specific surface area and unique physicochemical properties. Ferrous sulfide nanoparticles (FeS NPs) with the characteristics of high reactivity, large specific surface area, and low cost are widely applied to environmental remediation, catalysis, energy storage and medicine. However, there is no report on the application of FeS NPs in the antiviral field. In this study, gelatin stabilized FeS nanoparticles (Gel-FeS NPs) were large-scale synthesized rapidly by the one-pot method of co-precipitation of Fe²⁺ and S^2‒.

Results

The prepared Gel-FeS NPs exhibited good stability and dispersibility with an average diameter of 47.3 nm. Additionally, they were characterized with good biocompatibility and high antiviral activity against PRRSV proliferation in the stages of adsorption, invasion, and replication.

Conclusions

We reported for the first time the virucidal and antiviral activity of Gel-FeS NPs. The synthesized Gel-FeS NPs exhibited good dispersibility and biocompatibility as well as effective inhibition on PRRSV proliferation. Moreover, the Fe²⁺ released from degraded Gel-FeS NPs still displayed an antiviral effect, demonstrating the advantage of Gel-FeS NPs as an antiviral nanomaterial compared to other nanomaterials. This work highlighted the antiviral effect of Gel-FeS NPs and provided a new strategy for ferrous-based nanoparticles against PRRSV.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01281-4.

Antiviral peptide engineering for targeting membrane-enveloped viruses: Recent progress and future directions

Membrane-enveloped viruses are a major cause of global health challenges, including recent epidemics and pandemics. This mini-review covers the latest efforts to develop membrane-targeting antiviral peptides that inhibit enveloped viruses by 1) preventing virus-cell fusion or 2) disrupting the viral membrane envelope. The corresponding mechanisms of antiviral activity are discussed along with peptide engineering strategies to modulate membrane-peptide interactions in terms of potency and selectivity. Application examples are presented demonstrating how membrane-targeting antiviral peptides are useful therapeutics and prophylactics in animal models, while a stronger emphasis on biophysical concepts is proposed to refine mechanistic understanding and support potential clinical translation.

Supported Lipid Bilayer Platform for Characterizing the Membrane-Disruptive Behaviors of Triton X-100 and Potential Detergent Replacements

Triton X-100 (TX-100) is a widely used detergent to prevent viral contamination of manufactured biologicals and biopharmaceuticals, and acts by disrupting membrane-enveloped virus particles. However, environmental concerns about ecotoxic byproducts are leading to TX-100 phase out and there is an outstanding need to identify functionally equivalent detergents that can potentially replace TX-100. To date, a few detergent candidates have been identified based on viral inactivation studies, while direct mechanistic comparison of TX-100 and potential replacements from a biophysical interaction perspective is warranted. Herein, we employed a supported lipid bilayer (SLB) platform to comparatively evaluate the membrane-disruptive properties of TX-100 and a potential replacement, Simulsol SL 11W (SL-11W), and identified key mechanistic differences in terms of how the two detergents interact with phospholipid membranes. Quartz crystal microbalance-dissipation (QCM-D) measurements revealed that TX-100 was more potent and induced rapid, irreversible, and complete membrane solubilization, whereas SL-11W caused more gradual, reversible membrane budding and did not induce extensive membrane solubilization. The results further demonstrated that TX-100 and SL-11W both exhibit concentration-dependent interaction behaviors and were only active at or above their respective critical micelle concentration (CMC) values. Collectively, our findings demonstrate that TX-100 and SL-11W have distinct membrane-disruptive effects in terms of potency, mechanism of action, and interaction kinetics, and the SLB platform approach can support the development of biophysical assays to efficiently test potential TX-100 replacements.

Broad Spectrum Algae Compounds Against Viruses

The pharmaceutical industry is currently trying to develop new bioactive compounds to inactivate both enveloped and non-enveloped viruses for therapeutic purposes. Consequently, microalgal and macroalgal bioactive compounds are being explored by pharmaceutical, as well as biotechnology and food industries. In this review, we show how compounds produced by algae include important candidates for viral control applications. We discuss their mechanisms of action and activity against enveloped and non-enveloped viruses, including those causing infections by enteric, parenteral, and respiratory routes. Indeed, algal products have potential in human and animal medicine.

Role of Membrane Stretch in Adsorption of Antiviral Peptides onto Lipid Membranes and Membrane Pore Formation

Many medically important viruses are enveloped viruses, which are surrounded by a structurally conserved, host-derived lipid membrane coating. Agents that target and disrupt this membrane coating could potentially function as broad-spectrum antiviral drugs. The amphipathic α-helical (AH) peptide derived from the N-terminus of the hepatitis C virus NS5A protein is one such candidate and has been demonstrated to be able to selectively rupture lipid vesicles in the size range of viruses (<160 nm diameter). However, the mechanism underlying this membrane curvature selectivity remains elusive. In this study, we have performed molecular dynamics simulations to study the binding of the AH peptide to model membranes that are stretched to resemble the looser lipid headgroup packing present on highly curved outer membranes of nanoscale vesicles. We found that the AH peptide binds more favorably to membranes that are stretched. In addition, a tetrameric placement of peptides across the membrane induced stable pore formation in the stretched membrane. Thus, our results suggest that the AH peptide senses the high curvature of nanoscale vesicles via the enhanced exposure of lipid packing defects induced by membrane area strain.

Surfactants - Compounds for inactivation of SARS-CoV-2 and other enveloped viruses

We provide here a general view on the interactions of surfactants with viruses, with a particular emphasis on how such interactions can be controlled and employed for inhibiting the infectivity of enveloped viruses, including coronaviruses. The aim is to provide to interested scientists from different fields, including chemistry, physics, biochemistry, and medicine, an overview of the basic properties of surfactants and (corona)viruses, which are relevant to understanding the interactions between the two. Various types of interactions between surfactant and virus are important, and they act on different components of a virus such as the lipid envelope, membrane (envelope) proteins and nucleocapsid proteins. Accordingly, this cannot be a detailed account of all relevant aspects but instead a summary that bridges between the different disciplines. We describe concepts and cover a selection of the relevant literature as an incentive for diving deeper into the relevant material. Our focus is on more recent developments around the COVID-19 pandemic caused by SARS-CoV-2, applications of surfactants against the virus, and on the potential future use of surfactants for pandemic relief. We also cover the most important aspects of the historical development of using surfactants in combatting virus infections. We conclude that surfactants are already playing very important roles in various directions of defence against viruses, either directly, as in disinfection, or as carrier components of drug delivery systems for prophylaxis or treatment. By designing tailor-made surfactants, and consequently, advanced formulations, one can expect more and more effective use of surfactants, either directly as antiviral compounds or as part of more complex formulations.

Chemical design principles of next-generation antiviral surface coatings

The ongoing coronavirus disease 2019 (COVID-19) pandemic has accelerated efforts to develop high-performance antiviral surface coatings while highlighting the need to build a strong mechanistic understanding of the chemical design principles that underpin antiviral surface coatings. Herein, we critically summarize the latest efforts to develop antiviral surface coatings that exhibit virus-inactivating functions through disrupting lipid envelopes or protein capsids. Particular attention is focused on how cutting-edge advances in material science are being applied to engineer antiviral surface coatings with tailored molecular-level properties to inhibit membrane-enveloped and non-enveloped viruses. Key topics covered include surfaces functionalized with organic and inorganic compounds and nanoparticles to inhibit viruses, and self-cleaning surfaces that incorporate photocatalysts and triplet photosensitizers. Application examples to stop COVID-19 are also introduced and demonstrate how the integration of chemical design principles and advanced material fabrication strategies are leading to next-generation surface coatings that can help thwart viral pandemics and other infectious disease threats.

Lipid Nanoparticle Technology for Delivering Biologically Active Fatty Acids and Monoglycerides

There is enormous interest in utilizing biologically active fatty acids and monoglycerides to treat phospholipid membrane-related medical diseases, especially with the global health importance of membrane-enveloped viruses and bacteria. However, it is difficult to practically deliver lipophilic fatty acids and monoglycerides for therapeutic applications, which has led to the emergence of lipid nanoparticle platforms that support molecular encapsulation and functional presentation. Herein, we introduce various classes of lipid nanoparticle technology and critically examine the latest progress in utilizing lipid nanoparticles to deliver fatty acids and monoglycerides in order to treat medical diseases related to infectious pathogens, cancer, and inflammation. Particular emphasis is placed on understanding how nanoparticle structure is related to biological function in terms of mechanism, potency, selectivity, and targeting. We also discuss translational opportunities and regulatory needs for utilizing lipid nanoparticles to deliver fatty acids and monoglycerides, including unmet clinical opportunities.

Biophysical Measurement Strategies for Antiviral Drug Development: Recent Progress in Virus-Mimetic Platforms Down to the Single Particle Level

The rapid growth in the global human population has increased the prevalence of emerging infectious diseases, which poses a major risk to public health. In search of effective clinical solutions, the acquisition of knowledge and understanding of biomolecular processes associated with viral pathogens represents a prerequisite. In this context, biophysical engineering approaches are particularly promising since they can resolve biomolecular interactions systematically by circumventing the complexities associated with experiments involving natural biological systems. The engineering approaches encompass the design and construction of biomimetic platforms that simulate the physiological system. This approach enables us to characterize, measure, and quantitatively analyze biomolecular interactions.In this Account, we summarize biophysical measurements that our group has successfully adopted to develop broad-spectrum antiviral drugs based on the lipid envelope antiviral disruption (LEAD) strategy, targeting the structural integrity of the outer viral membrane to abrogate viral infectivity. We particularly focus on the engineering aspects related to the design and construction of the tethered lipid vesicle platform, which closely mimics the viral membrane. We first outline the development of the LEAD agents screening platform that integrates soft matter design components with biomaterials and surface functionalization strategies to facilitate parallel measurements tracking peptide-induced destabilization of nanoscale, virus-mimicking vesicles with tunable size and composition. Then, we describe how this platform can be effectively employed to gain insights into the membrane curvature dependency of certain peptides. The fundamental knowledge acquired through this systematic process is crucial in the identification and subsequent development of antiviral drug candidates. In particular, we highlight the development of curvature-sensitive α-helical (AH) peptides as a broad-spectrum antiviral agent that has been demonstrated as an effective therapeutic treatment against multiple enveloped viruses. Also, we introduce a tethered cluster of vesicles to mimic clusters of enveloped viruses, exhibiting higher infectivity levels in the biological system. Then, we discuss key considerations, including experimental artifacts, namely dye leakage and imaging-related photobleaching, and corresponding corrective measures to improve the accuracy of quantitative interpretation. With the ongoing development and application of the tethered lipid vesicle platform, there is a compelling opportunity to explore fundamental biointerfacial science and develop a new class of broad-spectrum antiviral agents to prepare for the future membrane-enveloped viral pandemics.

Cyclodextrin-based Pickering emulsions: functional properties and drug delivery applications

Cyclodextrins (CDs) are biocompatible, cyclic oligosaccharides that are widely used in various industrial applications and have intriguing interfacial science properties. While CD molecules typically have low surface activity, they are capable of stabilizing emulsions by inclusion complexation of oil-phase components at the oil/water interface, which results in Pickering emulsion formation. Such surfactant-free formulations have gained considerable attention in recent years, owing to their enhanced physical stability, improved tolerability, and superior environmental compatibility compared to conventional, surfactant-based emulsions. In this review, we critically describe the latest insights into the molecular mechanisms involved in CD stabilization of Pickering emulsions, including covering practical aspects such as methods to prepare CD-based Pickering emulsions, lipid encapsulation, and relevant stability issues. In addition, the rheological and textural features of CD-based Pickering emulsions are discussed and particular attention is focused on promising examples for drug delivery, cosmetic, and nutraceutical applications. The functionality of currently developed CD-based Pickering emulsions is also summarised, including examples such as antifungal uses, and we close by discussing emerging possibilities to utilize the molecular encapsulation of CD-based emulsions for translational medicine applications in the antiviral and antibacterial spaces.

Photosensitizing Antivirals

Antiviral action of various photosensitizers is already summarized in several comprehensive reviews, and various mechanisms have been proposed for it. However, a critical consideration of the matter of the area is complicated, since the exact mechanisms are very difficult to explore and clarify, and most publications are of an empirical and "phenomenological" nature, reporting a dependence of the antiviral action on illumination, or a correlation of activity with the photophysical properties of the substances. Of particular interest is substance-assisted photogeneration of highly reactive singlet oxygen (1O2). The damaging action of 1O2 on the lipids of the viral envelope can probably lead to a loss of the ability of the lipid bilayer of enveloped viruses to fuse with the lipid membrane of the host cell. Thus, lipid bilayer-affine 1O2 photosensitizers have prospects as broad-spectrum antivirals against enveloped viruses. In this short review, we want to point out the main types of antiviral photosensitizers with potential affinity to the lipid bilayer and summarize the data on new compounds over the past three years. Further understanding of the data in the field will spur a targeted search for substances with antiviral activity against enveloped viruses among photosensitizers able to bind to the lipid membranes.