Fullerene Derivatives Strongly Inhibit HIV-1 Replication by Affecting Virus Maturation without Impairing Protease Activity

Membrane modification in enhancement of virus removal: A critical review

Many waterborne diseases are related with viruses, and COVID-19 worldwide has raised the concern of virus security in water into the public horizon. Compared to other conventional water treatment processes, membrane technology can achieve satisfactory virus removal with fewer chemicals, and prevent the outbreaks of viruses to a maximal extent. Researchers developed new modification methods to improve membrane performance. This review focused on the membrane modifications that enhance the performance in virus removal. The characteristics of viruses and their removal by membrane filtration were briefly generalized, and membrane modifications were systematically discussed through different virus removal mechanisms, including size exclusion, hydrophilic and hydrophobic interactions, electronic interactions, and inactivation. Advanced functional materials for membrane modification were summarized based on their nature. Furthermore, it is suggested that membranes should be enhanced through different mechanisms mainly based on their ranks of pore size. The current review provided theoretical support regarding membrane modifications in the enhancement of virus removal and avenues for practical application.

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

Evaporable indano[60]fullerene ketone (FIDO) was converted to indano[60]fullerene thioketone (FIDS) in high yield by using Lawesson's reagent. Three compounds with different substituents in para position were successfully converted to the corresponding thioketones, showing that the reaction tolerates compounds with electron-donating and electron-withdrawing substituents. Computational studies with density functional theory revealed the unique vibrations of the thioketone group in FIDS. The molecular structure of FIDS was confirmed by single-crystal X-ray analysis. Bulk heterojunction organic solar cells using three evaporable fullerene derivatives (FIDO, FIDS, C60) as electron-acceptors were compared, and the open-circuit voltage with FIDS was 0.16 V higher than that with C60.

Nano-Enabled Antivirals for Overcoming Antibody Escaped Mutations Based SARS-CoV-2 Waves

This review discusses receptor-binding domain (RBD) mutations related to the emergence of various SARS-CoV-2 variants, which have been highlighted as a major cause of repetitive clinical waves of COVID-19. Our perusal of the literature reveals that most variants were able to escape neutralizing antibodies developed after immunization or natural exposure, pointing to the need for a sustainable technological solution to overcome this crisis. This review, therefore, focuses on nanotechnology and the development of antiviral nanomaterials with physical antagonistic features of viral replication checkpoints as such a solution. Our detailed discussion of SARS-CoV-2 replication and pathogenesis highlights four distinct checkpoints, the S protein (ACE2 receptor coupling), the RBD motif (ACE2 receptor coupling), ACE2 coupling, and the S protein cleavage site, as targets for the development of nano-enabled solutions that, for example, prevent viral attachment and fusion with the host cell by either blocking viral RBD/spike proteins or cellular ACE2 receptors. As proof of this concept, we highlight applications of several nanomaterials, such as metal and metal oxide nanoparticles, carbon-based nanoparticles, carbon nanotubes, fullerene, carbon dots, quantum dots, polymeric nanoparticles, lipid-based, polymer-based, lipid-polymer hybrid-based, surface-modified nanoparticles that have already been employed to control viral infections. These nanoparticles were developed to inhibit receptor-mediated host-virus attachments and cell fusion, the uncoating of the virus, viral gene expression, protein synthesis, the assembly of progeny viral particles, and the release of the virion. Moreover, nanomaterials have been used as antiviral drug carriers and vaccines, and nano-enabled sensors have already been shown to enable fast, sensitive, and label-free real-time diagnosis of viral infections. Nano-biosensors could, therefore, also be useful in the remote testing and tracking of patients, while nanocarriers probed with target tissue could facilitate the targeted delivery of antiviral drugs to infected cells, tissues, organs, or systems while avoiding unwanted exposure of non-target tissues. Antiviral nanoparticles can also be applied to sanitizers, clothing, facemasks, and other personal protective equipment to minimize horizontal spread. We believe that the nanotechnology-enabled solutions described in this review will enable us to control repeated SAR-CoV-2 waves caused by antibody escape mutations.

In vitro and in silico studies of the antiviral activity of polyhydrated fullerenes against influenza A (H1N1) virus

As of today, influenza viruses remain a relevant target for the development of antiviral compounds due to their rapid evolution and acquisition of the resistance to existing drugs. Fullerene derivatives have already shown the ability to successfully interact with viruses, and polyhydrated fullerenes (or fullerenols) are particularly attractive due to their compatibility with biological fluids and low toxicity. Therefore, the goal of this work was to study the effect of two batches of a mixture of polyhydrated fullerenes with a mass ratio of 78.1% C₆₀/C₇₀ and 21.9% C₇₆/C₇₈/C₈₄ on the influenza A (H1N1) virus. It was determined that the mixture of fullerenols, along with the low toxicity, showed high antiviral activity with a decrease in the viral infectious titer up to 4 orders of magnitude. In addition, studied fullerenols did not affect the hemagglutination process and did not show any significant prophylactic activity. With the help of molecular docking and molecular dynamics simulation, the likely target of fullerenols' action was determined-the binding site of the RNA primer of the viral RNA-dependent RNA polymerase. Therefore, we assume that the high antiviral effect of polyhydrated fullerenes on influenza A virus is related to their interaction with the viral RNA polymerase.

Recent Advances in Carbon-Based Electrodes for Energy Storage and Conversion

Carbon-based nanomaterials, including graphene, fullerenes, and carbon nanotubes, are attracting significant attention as promising materials for next-generation energy storage and conversion applications. They possess unique physicochemical properties, such as structural stability and flexibility, high porosity, and tunable physicochemical features, which render them well suited in these hot research fields. Technological advances at atomic and electronic levels are crucial for developing more efficient and durable devices. This comprehensive review provides a state-of-the-art overview of these advanced carbon-based nanomaterials for various energy storage and conversion applications, focusing on supercapacitors, lithium as well as sodium-ion batteries, and hydrogen evolution reactions. Particular emphasis is placed on the strategies employed to enhance performance through nonmetallic elemental doping of N, B, S, and P in either individual doping or codoping, as well as structural modifications such as the creation of defect sites, edge functionalization, and inter-layer distance manipulation, aiming to provide the general guidelines for designing these devices by the above approaches to achieve optimal performance. Furthermore, this review delves into the challenges and future prospects for the advancement of carbon-based electrodes in energy storage and conversion.

An endophytic fungus, Penicillium simplicissimum conjugated with C60 fullerene for its potential antimitotic, anti-inflammatory, anticancer and photodegradation activities

In the present study, endophytic fungus, Penicillium simplicissimum isolated from Loranthus micranthus was used to analyze phytochemical studies by qualitative and GC-MS methods. The endophytic fungus P. simplicissimum yielded novel compound penisimplicissin identified through GC-MS studies. Further, P. simplicissimum was conjugated with C60 fullerene nanoparticles (Ps-FNPs) were verified using UV-vis spectra, XRD, FTIR, DLS, EDX and SEM. Ps-FNPs was confirmed using UV-visible spectra with a peak at 260 nm. The IR bands were recorded at 2085, 1428, 1181, 661, 652, 644, 628, and 604 cm-1. The Ps-FNPs treated cells showed a nucleolar shrinkage and cell arrest atprophase, binuclear and multinucleolar cells, a chromosomal bridge and diversion at anaphase was observed, whereas, chromosomal fragment and abnormal distribution at metaphase stage. The Ps-FNPs exhibited a noteworthy anticancer activity on lung cancer cell line H1975 through cytotoxicity. The cytotoxicity was induced by increasing caspase-3, 7, and 9 activities and also showed highest inhibition in xanthine oxidase and COX-II assay proved good anti-inflammatory activity. Ps-FNPs have been extensively studied for photocatalytic activity test against Rhodamine B, Methylene blue and nigrosine showed potential dye degradation in the presence of sunlight proved to be novel photocatalysts. With all the results recorded, Ps-FNPs also have a synergetic effect having on anti-mitotic, anticancer, anti-inflammation potential and photocatalytic degradation of dyes. Hence, the conjugated Ps-FNPs could be one of the potent nano-drug formulations in future. Thus, the present study gives a clear idea of the multifaceted therapeutic and photocatalytic applications.

Progress in Antiviral Fullerene Research

Unlike traditional small molecule drugs, fullerene is an all-carbon nanomolecule with a spherical cage structure. Fullerene exhibits high levels of antiviral activity, inhibiting virus replication in vitro and in vivo. In this review, we systematically summarize the latest research regarding the different types of fullerenes investigated in antiviral studies. We discuss the unique structural advantage of fullerenes, present diverse modification strategies based on the addition of various functional groups, assess the effect of structural differences on antiviral activity, and describe the possible antiviral mechanism. Finally, we discuss the prospective development of fullerenes as antiviral drugs.

Novel C60 Fullerenol-Gentamicin Conjugate–Physicochemical Characterization and Evaluation of Antibacterial and Cytotoxic Properties

This study aimed to develop, characterize, and evaluate antibacterial and cytotoxic properties of novel fullerene derivative composed of C₆₀ fullerenol and standard aminoglycoside antibiotic–gentamicin (C₆₀ fullerenol-gentamicin conjugate). The successful introduction of gentamicin to fullerenol was confirmed by X-ray photoelectron spectroscopy which together with thermogravimetric and spectroscopic analysis revealing the formula of the composition as C₆₀(OH)₁₂(GLYMO)₁₁(Gentamicin)_0.8. The dynamic light scattering (DLS) revealed that conjugate possessed ability to form agglomerates in water (size around 115 nm), while Zeta potential measurements demonstrated that such agglomerates possessed neutral character. In vitro biological assays indicated that obtained C₆₀ fullerenol-gentamicin conjugate possessed the same antibacterial activity as standard gentamicin against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli, which proves that combination of fullerenol with gentamicin does not cause the loss of antibacterial activity of antibiotic. Moreover, cytotoxicity assessment demonstrated that obtained fullerenol-gentamicin derivative did not decrease viability of normal human fibroblasts (model eukaryotic cells) compared to control fibroblasts. Thus, taking into account all of the results, it can be stated that this research presents effective method to fabricate C₆₀ fullerenol-gentamicin conjugate and proves that such derivative possesses desired antibacterial properties without unfavorable cytotoxic effects towards eukaryotic cells in vitro. These promising preliminary results indicate that obtained C₆₀ fullerenol-gentamicin conjugate could have biomedical potential. It may be presumed that obtained fullerenol may be used as an effective carrier for antibiotic, and developed fullerenol-gentamicin conjugate may be apply locally (i.e., at the wound site). Moreover, in future we will evaluate possibility of its applications in inter alia tissue engineering, namely as a component of wound dressings and implantable biomaterials.

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.

Progress in Diamanes and Diamanoids Nanosystems for Emerging Technologies

New materials are the backbone of their technology-driven modern civilization and at present carbon nanostructures are the leading candidates that have attracted huge research activities. Diamanes and diamanoids are the new nanoallotropes of sp3 hybridized carbon which can be fabricated by proper functionalization, substitution, and via Birch reduction under controlled pressure using graphitic system as a precursor. These nanoallotropes exhibit outstanding electrical, thermal, optical, vibrational, and mechanical properties, which can be an asset for new technologies, especially for quantum devices, photonics, and space technologies. Moreover, the features like wide bandgap, tunable thermal conductivity, excellent thermal insulation, etc. make diamanes and diamanoids ideal candidates for nano-electrical devices, nano-resonators, optical waveguides, and the next generation thermal management systems. In this review, diamanes and diamanoids are discussed in detail in terms of its historical prospect, method of synthesis, structural features, broad properties, and cutting-edge applications. Additionally, the prospects of diamanes and diamanoids for new applications are carefully discussed. This review aims to provide a critical update with important ideas for a new generation of quantum devices based on diamanes and diamanoids which are going to be an important topic in the future of carbon nanotechnology.

Fullerene Derivatives Prevent Packaging of Viral Genomic RNA into HIV-1 Particles by Binding Nucleocapsid Protein

Fullerene derivatives with hydrophilic substituents have been shown to exhibit a range of biological activities, including antiviral ones. For a long time, the anti-HIV activity of fullerene derivatives was believed to be due to their binding into the hydrophobic pocket of HIV-1 protease, thereby blocking its activity. Recent work, however, brought new evidence of a novel, protease-independent mechanism of fullerene derivatives' action. We studied in more detail the mechanism of the anti-HIV-1 activity of N,N-dimethyl[70]fulleropyrrolidinium iodide fullerene derivatives. By using a combination of in vitro and cell-based approaches, we showed that these C₇₀ derivatives inhibited neither HIV-1 protease nor HIV-1 maturation. Instead, our data indicate effects of fullerene C₇₀ derivatives on viral genomic RNA packaging and HIV-1 cDNA synthesis during reverse transcription-without impairing reverse transcriptase activity though. Molecularly, this could be explained by a strong binding affinity of these fullerene derivatives to HIV-1 nucleocapsid domain, preventing its proper interaction with viral genomic RNA, thereby blocking reverse transcription and HIV-1 infectivity. Moreover, the fullerene derivatives' oxidative activity and fluorescence quenching, which could be one of the reasons for the inconsistency among reported anti-HIV-1 mechanisms, are discussed herein.

Past and Current Progress in the Development of Antiviral/Antimicrobial Polymer Coating towards COVID-19 Prevention: A Review

The astonishing outbreak of SARS-CoV-2 coronavirus, known as COVID-19, has attracted numerous research interests, particularly regarding fabricating antimicrobial surface coatings. This initiative is aimed at overcoming and minimizing viral and bacterial transmission to the human. When contaminated droplets from an infected individual land onto common surfaces, SARS-CoV-2 coronavirus is able to survive on various surfaces for up to 9 days. Thus, the possibility of virus transmission increases after touching or being in contact with contaminated surfaces. Herein, we aim to provide overviews of various types of antiviral and antimicrobial coating agents, such as antimicrobial polymer-based coating, metal-based coating, functional nanomaterial, and nanocomposite-based coating. The action mode for each type of antimicrobial agent against pathogens is elaborated. In addition, surface properties of the designed antiviral and antimicrobial polymer coating with their influencing factors are discussed in this review. This paper also exhibits several techniques on surface modification to improve surface properties. Various developed research on the development of antiviral/antimicrobial polymer coating to curb the COVID-19 pandemic are also presented in this review.

Biomedical Applications of Carbon Nanomaterials: Fullerenes, Quantum Dots, Nanotubes, Nanofibers, and Graphene

Carbon nanomaterials (CNMs) have received tremendous interest in the area of nanotechnology due to their unique properties and flexible dimensional structure. CNMs have excellent electrical, thermal, and optical properties that make them promising materials for drug delivery, bioimaging, biosensing, and tissue engineering applications. Currently, there are many types of CNMs, such as quantum dots, nanotubes, nanosheets, and nanoribbons; and there are many others in development that promise exciting applications in the future. The surface functionalization of CNMs modifies their chemical and physical properties, which enhances their drug loading/release capacity, their ability to target drug delivery to specific sites, and their dispersibility and suitability in biological systems. Thus, CNMs have been effectively used in different biomedical systems. This review explores the unique physical, chemical, and biological properties that allow CNMs to improve on the state of the art materials currently used in different biomedical applications. The discussion also embraces the emerging biomedical applications of CNMs, including targeted drug delivery, medical implants, tissue engineering, wound healing, biosensing, bioimaging, vaccination, and photodynamic therapy.

Antitumor efficiency of the natural alkaloid berberine complexed with C60 fullerene in Lewis lung carcinoma in vitro and in vivo

Background

Berberine (Ber) is a herbal alkaloid with pharmacological activity in general and a high anticancer potency in particular. However, due to its low bioavailability, the difficulty in reaching a target and choosing the right dose, there is a need to improve approaches of Ber use in anticancer therapy. In this study, Ber, noncovalently bound to a carbon nanostructure C60 fullerene (C60) at various molar ratios of the components, was explored against Lewis lung carcinoma (LLC).

Methods

C60–Ber noncovalent nanocomplexes were synthesized in 1:2, 1:1 and 2:1 molar ratios. Ber release from the nanocomplexes was studied after prolonged incubation at different pH with the liquid chromatography–mass spectrometry analysis of free Ber content. Biological effects of the free and C60-complaxated Ber were studied in vitro towards LLC cells with phase-contrast and fluorescence microscopy, flow cytometry, MTT reduction, caspase activity and wound closure assays. The treatment with C60–Ber nanocomplex was evaluated in vivo with the LLC-tumored C57Bl mice. The mice body weight, tumor size, tumor weight and tumor weight index were assessed for four groups, treated with saline, 15 mg C60/kg, 7.5 mg Ber/kg or 2:1 C60-Ber nanocomplex (15 mg C60/kg, 7.5 mg Ber/kg).

Results

Ber release from C60–Ber nanocomplexes was promoted with medium acidification. LLC cells treatment with C60–Ber nanocomplexes was followed by enhanced Ber intracellular uptake as compared to free Ber. The cytotoxicity of the studied agents followed the order: free Ber < 1:2 < 1:1 < 2:1 C60–Ber nanocomplex. The potency of cytotoxic effect of 2:1 C60–Ber nanocomplex was confirmed by 21.3-fold decrease of IC50 value (0.8 ± 0.3 µM) compared to IC50 for free Ber (17 ± 2 µM). C60–Ber nanocomplexes induced caspase 3/7 activation and suppressed the migration activity of LLC cells. The therapeutic potency of 2:1 C60–Ber nanocomplex was confirmed in a mouse model of LLC. The tumor growth in the group treated with 2:1 C60–Ber nanocomplex is suppressed by approximately 50% at the end of experiment, while in the tumor-bearing group treated with free Ber no therapeutic effect was detected.

Conclusions

This study indicates that complexation of natural alkaloid Ber with C60 may be a novel therapeutic strategy against lung carcinoma.

Graphical abstract

Use of nanotechnology in combating coronavirus

Recent COVID-19 pandemic situation caused due to the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affected global health as well as economics. There is global attention on prevention, diagnosis as well as treatment of COVID-19 infection which would help in easing the current situation. The use of nanotechnology and nanomedicine has been considered to be promising due to its excellent potential in managing various medical issues such as viruses which is a major threat. Nanoparticles have shown great potential in various biomedical applications and can prove to be of great use in antiviral therapy, especially over other conventional antiviral agents. This review focusses on the pathophysiology of SARS-CoV-2 and the progression of the COVID-19 disease followed by currently available treatments for the same. Use of nanotechnology has been elaborated by exploiting various nanoparticles like metal and metal oxide nanoparticles, carbon-based nanoparticles, quantum dots, polymeric nanoparticles as well as lipid-based nanoparticles along with its mechanism of action against viruses which can prove to be beneficial in COVID-19 therapeutics. However, it needs to be considered that use of these nanotechnology-based approaches in COVID-19 therapeutics only aids the human immunity in fighting the infection. The main function is performed by the immune system in combatting any infection.

Antiviral Nanomaterials for Designing Mixed Matrix Membranes

Membranes are helpful tools to prevent airborne and waterborne pathogenic microorganisms, including viruses and bacteria. A membrane filter can physically separate pathogens from air or water. Moreover, incorporating antiviral and antibacterial nanoparticles into the matrix of membrane filters can render composite structures capable of killing pathogenic viruses and bacteria. Such membranes incorporated with antiviral and antibacterial nanoparticles have a great potential for being applied in various application scenarios. Therefore, in this perspective article, we attempt to explore the fundamental mechanisms and recent progress of designing antiviral membrane filters, challenges to be addressed, and outlook.

Multivalent Tryptophan- and Tyrosine-Containing [60]Fullerene Hexa-Adducts as Dual HIV and Enterovirus A71 Entry Inhibitors

Unprecedented 3D hexa‐adducts of [60]fullerene peripherally decorated with twelve tryptophan (Trp) or tyrosine (Tyr) residues have been synthesized. Studies on the antiviral activity of these novel compounds against HIV and EV71 reveal that they are much more potent against HIV and equally active against EV71 than the previously described dendrimer prototypes AL‐385 and AL‐463, which possess the same number of Trp/Tyr residues on the periphery but attached to a smaller and more flexible pentaerythritol core. These results demonstrate the relevance of the globular 3D presentation of the peripheral groups (Trp/Tyr) as well as the length of the spacer connecting them to the central core to interact with the viral envelopes, particularly in the case of HIV, and support the hypothesis that [60]fullerene can be an alternative and attractive biocompatible carbon‐based scaffold for this type of highly symmetrical dendrimers. In addition, the functionalized fullerenes here described, which display twelve peripheral negatively charged indole moieties on their globular surface, define a new and versatile class of compounds with a promising potential in biomedical applications.

Nanotechnology-based antiviral therapeutics

The host immune system is highly compromised in case of viral infections and relapses are very common. The capacity of the virus to destroy the host cell by liberating its own DNA or RNA and replicating inside the host cell poses challenges in the development of antiviral therapeutics. In recent years, many new technologies have been explored for diagnosis, prevention, and treatment of viral infections. Nanotechnology has emerged as one of the most promising technologies on account of its ability to deal with viral diseases in an effective manner, addressing the limitations of traditional antiviral medicines. It has not only helped us to overcome problems related to solubility and toxicity of drugs, but also imparted unique properties to drugs, which in turn has increased their potency and selectivity toward viral cells against the host cells. The initial part of the paper focuses on some important proteins of influenza, Ebola, HIV, herpes, Zika, dengue, and corona virus and those of the host cells important for their entry and replication into the host cells. This is followed by different types of nanomaterials which have served as delivery vehicles for the antiviral drugs. It includes various lipid-based, polymer-based, lipid-polymer hybrid-based, carbon-based, inorganic metal-based, surface-modified, and stimuli-sensitive nanomaterials and their application in antiviral therapeutics. The authors also highlight newer promising treatment approaches like nanotraps, nanorobots, nanobubbles, nanofibers, nanodiamonds, nanovaccines, and mathematical modeling for the future. The paper has been updated with the recent developments in nanotechnology-based approaches in view of the ongoing pandemic of COVID-19.Graphical abstract.

Nanotechnology-based approaches for emerging and re-emerging viruses: Special emphasis on COVID-19

In recent decades, the major concern of emerging and re-emerging viral diseases has become an increasingly important area of public health concern, and it is of significance to anticipate future pandemic that would inevitably threaten human lives. The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly emerged virus that causes mild to severe pneumonia. Coronavirus disease (COVID-19) became a very much concerned issue worldwide after its super-spread across the globe and emerging viral diseases have not got specific and reliable diagnostic and treatments. As the COVID-19 pandemic brings about a massive life-loss across the globe, there is an unmet need to discover a promising and typically effective diagnosis and treatment to prevent super-spreading and mortality from being decreased or even eliminated. This study was carried out to overview nanotechnology-based diagnostic and treatment approaches for emerging and re-emerging viruses with the current treatment of the disease and shed light on nanotechnology's remarkable potential to provide more effective treatment and prevention to a special focus on recently emerged coronavirus.

Synthesis, Characterization, Cellular Uptake, and In Vitro Anticancer Activity of Fullerenol-Doxorubicin Conjugates

Doxorubicin (DOX) is one of the most commonly used chemotherapeutic agents for treating human cancer. However, its clinical use has been limited by DOX-induced cardiotoxicity as well as other side effects. In the present study, we designed and synthesized the fullerenol (FU)-DOX conjugates and folic acid (FA)-grafted FU-DOX conjugates for improving the selectivity and activity of DOX in cancer cells. We further characterized the physicochemical properties and examined the release kinetics, cellular uptake, and in vitro anticancer activities of FU-DOX and FA-FU-DOX. The results showed that FU-DOX and FA-FU-DOX had a mean diameter of <200 nm and a low polydispersity. Both FU-DOX and FA-FU-DOX exhibited pH sensitivity and their DOX release rates were higher at pH 5.9 vs. pH 7.4. The cellular uptake studies indicated that FU conjugation enhanced the intracellular accumulation of DOX in human hepatocellular carcinoma (HCC) cell lines (BEL-7402 and HepG2) and the immortalized normal human hepatocytes (L02). The conjugation of FA to FU-DOX further promoted the drug internalization in an FR-dependent manner and enhanced the cytotoxicity against HCC cells. In conclusion, the newly prepared FA-FU-DOX conjugates can optimize the safety and efficacy profile of DOX.

Nano-based approaches in the development of antiviral agents and vaccines

Outbreaks and the rapid transmission of viruses, such as coronaviruses and influenza viruses, are serious threats to human health. A major challenge in combating infectious diseases caused by viruses is the lack of effective methods for prevention and treatment. Nanotechnology has provided a basis for the development of novel antiviral strategies. Owing to their large modifiable surfaces that can be functionalized with multiple molecules to realize sophisticated designs, nanomaterials have been developed as nanodrugs, nanocarriers, and nano-based vaccines to effectively induce sufficient immunologic memory. From this perspective, we introduce various nanomaterials with diverse antiviral mechanisms and summarize how nano-based antiviral agents protect against viral infection at the molecular, cellular, and organismal levels. We summarize the applications of nanomaterials for defense against emerging viruses by trapping and inactivating viruses and inhibiting viral entry and replication. We also discuss recent progress in nano-based vaccines with a focus on the mechanisms by which nanomaterials contribute to immunogenicity. We further describe how nanotechnology may improve vaccine efficacy by delivering large amounts of antigens to target immune cells and enhancing the immune response by mimicking viral structures and activating dendritic cells. Finally, we provide an overview of future prospects for nano-based antiviral agents and vaccines.

Hard Nanomaterials in Time of Viral Pandemics

The SARS-Cov-2 pandemic has spread worldwide during 2020, setting up an uncertain start of this decade. The measures to contain infection taken by many governments have been extremely severe by imposing home lockdown and industrial production shutdown, making this the biggest crisis since the second world war. Additionally, the continuous colonization of wild natural lands may touch unknown virus reservoirs, causing the spread of epidemics. Apart from SARS-Cov-2, the recent history has seen the spread of several viral pandemics such as H2N2 and H3N3 flu, HIV, and SARS, while MERS and Ebola viruses are considered still in a prepandemic phase. Hard nanomaterials (HNMs) have been recently used as antimicrobial agents, potentially being next-generation drugs to fight viral infections. HNMs can block infection at early (disinfection, entrance inhibition) and middle (inside the host cells) stages and are also able to mitigate the immune response. This review is focused on the application of HNMs as antiviral agents. In particular, mechanisms of actions, biological outputs, and limitations for each HNM will be systematically presented and analyzed from a material chemistry point-of-view. The antiviral activity will be discussed in the context of the different pandemic viruses. We acknowledge that HNM antiviral research is still at its early stage, however, we believe that this field will rapidly blossom in the next period.

Advances in Antiviral Material Development

The rise in human pandemics demands prudent approaches in antiviral material development for disease prevention and treatment via effective protective equipment and therapeutic strategy. However, the current state of the antiviral materials research is predominantly aligned towards drug development and its related areas, catering to the field of pharmaceutical technology. This review distinguishes the research advances in terms of innovative materials exhibiting antiviral activities that take advantage of fast-developing nanotechnology and biopolymer technology. Essential concepts of antiviral principles and underlying mechanisms are illustrated, followed with detailed descriptions of novel antiviral materials including inorganic nanomaterials, organic nanomaterials and biopolymers. The biomedical applications of the antiviral materials are also elaborated based on the specific categorization. Challenges and future prospects are discussed to facilitate the research and development of protective solutions and curative treatments.

Pristine C60 Fullerene Nanoparticles Ameliorate Hyperglycemia-Induced Disturbances via Modulation of Apoptosis and Autophagy Flux

Diabetes mellitus is a prevalent metabolic disorder associated with multiple complications including neuropathy, memory loss and cognitive decline. Despite a long history of studies on diabetic complications, there are no effective therapeutic strategies for neuroprotection in diabetes. Hyperglycemia-induced imbalance in programmed cell death could initiate a decline in neural tissue cells viability. Various nanomaterials can induce either cell death or cell survival dependent on the type and surface features. Pristine C₆₀ fullerene is a nontoxic nanomaterial, which exhibits antioxidant and cytoprotective properties. However, the precise molecular mechanism with which the C₆₀ nanoparticle exerts cytoprotective effect in diabetic subjects has not yet been fully addressed. Thus, this study aimed to determine whether C₆₀ fullerene prevents oxidative stress impairment and to explore the effects of C₆₀ fullerene on apoptosis and autophagy in diabetes mellitus to clarify its potential mechanisms. These effects have been examined for olive oil extracted C₆₀ fullerene on the hippocampus of STZ diabetic rats. Up-regulation of Caspase-3, Beclin-1 and oxidative stress indexes and down-regulation of Bcl-2 were observed in the brain of STZ-diabetic rats. The exposure to C₆₀ fullerene for a period of 12 weeks ameliorate redox imbalance, hyperglycemia-induced disturbances in apoptosis and autophagy flux via modulation of Caspase-3, Bcl-2, Beclin-1 and LC3I/II contents. Furthermore, C₆₀ fullerene ameliorated the LC3I/II ratio and prevented extremely increased autophagy flux. Contrarily, pristine C₆₀ fullerene had no modulatory effect on all studied apoptotic and autophagy markers in non-diabetic groups. Therefore, oil extracted C₆₀ fullerene exhibits cytoprotective effect in hyperglycemia-stressed hippocampal cells. The presented results confirm that pristine C₆₀ fullerene nanoparticles can protect hippocampal cells against hyperglycemic stress via anti-oxidant, anti-apoptotic effects and amelioration of autophagy flux. Moreover, C₆₀ fullerene regulates a balance of autophagy via BCL-2/Beclin-1 reciprocal expression that could prevent functional disturbances in hippocampus.

Carbon-based antiviral nanomaterials: graphene, C-dots, and fullerenes. A perspective

The appearance of new and lethal viruses and their potential threat urgently requires innovative antiviral systems. In addition to the most common and proven pharmacological methods, nanomaterials can represent alternative resources to fight viruses at different stages of infection, by selective action or in a broad spectrum. A fundamental requirement is non-toxicity. However, biocompatible nanomaterials have very often little or no antiviral activity, preventing their practical use. Carbon-based nanomaterials have displayed encouraging results and can present the required mix of biocompatibility and antiviral properties. In the present review, the main candidates for future carbon nanometric antiviral systems, namely graphene, carbon dots and fullerenes, have been critically analysed. In general, different carbon nanostructures allow several strategies to be applied. Some of the materials have peculiar antiviral properties, such as singlet oxygen emission, or the capacity to interfere with virus enzymes. In other cases, nanomaterials have been used as a platform for functional molecules able to capture and inhibit viral activity. The use of carbon-based biocompatible nanomaterials as antivirals is still an almost unexplored field, while the published results show promising prospects.

Inactivation of HIV-1 Infection through Integrative Blocking with Amino Phenylboronic Acid Attributed Carbon Dots

Current antiretroviral HIV therapies continue to have problems related to procedural complications, toxicity, and uncontrolled side effects. In this study, amino phenylboronic acid-modified carbon dots (APBA-CDs) were introduced as a new nanoparticle-based on gp120 targeting that inhibits HIV-1 entry processes. Prolonged by simple pyrolysis for preparing carbon dots, this report further explores attributing amino phenylboronic acid on carbon dots, which prove the formation of graphene-like structures on carbon dots and boronic acid sites, thereby enabling the enhancement of positive optical properties through photoluminescent detection. Aside from performing well in terms of biocompatibility and low cytotoxicity (the CC₅₀ reach up to 11.2 mg/mL), APBA-CDs exhibited superior capabilities in terms of prohibiting HIV-1 entry onto targeted MOLT-4 cells recognized by the delimitations of syncitia formation and higher ATP signal rather than bare carbon dots. The modified carbon dots also promote dual-action on HIV-1 treatment by both intracellularly and extracellularly viral blocking by combining with the Duviral drug, along with compressing p24 antigen signals that are better than APBA-CDs and Duviral itself.

Fullerene Derivatives as Lung Cancer Cell Inhibitors: Investigation of Potential Descriptors Using QSAR Approaches

Background

Nanotechnology-based strategies in the treatment of cancer have potential advantages because of the favorable delivery of nanoparticles into tumors through porous vasculature.

Materials and Methods

In the current study, we synthesized a series of water-soluble fullerene derivatives and observed their anti-tumor effects on human lung carcinoma A549 cell lines. The quantitative structure–activity relationship (QSAR) modeling was employed to investigate the relationship between anticancer effects and descriptors relevant to peculiarities of molecular structures of fullerene derivatives.

Results

In the QSAR regression model, the evaluation results revealed that the determination coefficient r² and leave-one-out cross-validation q² for the recommended QSAR model were 0.9966 and 0.9246, respectively, indicating the reliability of the results. The molecular modeling showed that the lack of chlorine atom and a lower number of aliphatic single bonds in saturated hydrocarbon chains may be positively correlated with the lung cancer cytotoxicity of fullerene derivatives. Synthesized water-soluble fullerene derivatives have potential functional groups to inhibit the proliferation of lung cancer cells.

Conclusion

The guidelines obtained from the QSAR model might strongly facilitate the rational design of potential fullerene-based drug candidates for lung cancer therapy in the future.

Thiophene-based water-soluble fullerene derivatives as highly potent antiherpetic pharmaceuticals

Here we report the Friedel-Crafts arylation of chlorofullerenes C60Cl6 and C70Cl8 with thiophene-based methyl esters. While C60Cl6 formed expected Cs-C60R5Cl products, C70Cl8 demonstrated a tendency for both substitution of chlorine atoms and addition of an extra thiophene unit, thus forming Cs-C70R8 and C1-C70R9H compounds. The synthesized water-soluble C60 and C70 fullerene derivatives with thiophene-based addends demonstrated high activity against a broad range of viruses, including human immunodeficiency virus, influenza virus, cytomegalovirus, and herpes simplex virus. The record activity of C70 fullerene derivatives against herpes simplex virus together with low toxicity in mice makes them promising candidates for the development of novel non-nucleoside antiherpetic drugs.

Nano-based approach to combat emerging viral (NIPAH virus) infection

Emergence of new virus and their heterogeneity are growing at an alarming rate. Sudden outburst of Nipah virus (NiV) has raised serious question about their instant management using conventional medication and diagnostic measures. A coherent strategy with versatility and comprehensive perspective to confront the rising distress could perhaps be effectuated by implementation of nanotechnology. But in concurrent to resourceful and precise execution of nano-based medication, there is an ultimate need of concrete understanding of the NIV pathogenesis. Moreover, to amplify the effectiveness of nano-based approach in a conquest against NiV, a list of developed nanosystem with antiviral activity is also a prerequisite. Therefore the present review provides a meticulous cognizance of cellular and molecular pathogenesis of NiV. Conventional as well several nano-based diagnosis experimentations against viruses have been discussed. Lastly, potential efficacy of different forms of nano-based systems as convenient means to shield mankind against NiV has also been introduced.

Complexation with C60 Fullerene Increases Doxorubicin Efficiency against Leukemic Cells In Vitro

Conventional anticancer chemotherapy is limited because of severe side effects as well as a quickly evolving multidrug resistance of the tumor cells. To address this problem, we have explored a C₆₀ fullerene-based nanosized system as a carrier for anticancer drugs for an optimized drug delivery to leukemic cells.Here, we studied the physicochemical properties and anticancer activity of C₆₀ fullerene noncovalent complexes with the commonly used anticancer drug doxorubicin. C₆₀-Doxorubicin complexes in a ratio 1:1 and 2:1 were characterized with UV/Vis spectrometry, dynamic light scattering, and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The obtained analytical data indicated that the 140-nm complexes were stable and could be used for biological applications. In leukemic cell lines (CCRF-CEM, Jurkat, THP1 and Molt-16), the nanocomplexes revealed ≤ 3.5 higher cytotoxic potential in comparison with the free drug in a range of nanomolar concentrations. Also, the intracellular drug's level evidenced C₆₀ fullerene considerable nanocarrier function.The results of this study indicated that C₆₀ fullerene-based delivery nanocomplexes had a potential value for optimization of doxorubicin efficiency against leukemic cells.

A new family of fullerene derivatives: Fullerene-curcumin conjugates for biological and photovoltaic applications

The synthesis and characterization of a family of [60]fullerocurcuminoids obtained via Bingel reactions is reported. The new C60 derivatives include curcumin and curcuminoids with a variety of end groups. Preliminary biological experiments show the potential activity of the compound containing a curcumin addend, which exhibits moderate anti-HIV-1 and radical scavenger properties, but no anti-cancer activity. In addition, the new fullerocurcuminoids exhibit HOMO/LUMO energy levels that are reasonably matched with those of perovskites and when they were tested in perovskite solar cells (PSCs) as the electron transporting material (ETM), photoconversion efficiencies ranging from 14.04%-14.95% were obtained, whereas a value of 16.23% was obtained for [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) based devices.

Harnessing nanostructured systems for improved treatment and prevention of HIV disease

Combination antiretroviral therapy effectively controls human immunodeficiency virus (HIV) viral replication, delaying the progression to acquired immune deficiency syndrome and improving and extending quality of life of patients. However, the inability of antiretroviral therapeutics to target latent virus and their poor penetration of viral reserve tissues result in the need for continued treatment for the life of the patient. Side effects from long-term antiretroviral use and the development of drug resistance due to patient noncompliance are also continuing problems. Nanostructured systems of antiretroviral therapeutics have the potential to improve targeted delivery to viral reservoirs, reduce drug toxicity, and increase dosing intervals, thereby improving treatment outcomes and enhancing patient adherence. Despite these advantages, very few nanostructured antiretroviral delivery systems have made it to clinical trials due to challenges in preclinical and clinical development. In this context, we review the current challenges in HIV disease management, and the recent progress in leveraging the unique performance of nanostructured systems in therapeutic delivery for improved treatment and prevention of this incurable human disease.

Carbon-based hybrid nanogels: a synergistic nanoplatform for combined biosensing, bioimaging, and responsive drug delivery

Nanosized crosslinked polymer networks, named as nanogels, are playing an increasingly important role in a diverse range of applications by virtue of their porous structures, large surface area, good biocompatibility and responsiveness to internal and/or external chemico-physical stimuli. Recently, a variety of carbon nanomaterials, such as carbon quantum dots, graphene/graphene oxide nanosheets, fullerenes, carbon nanotubes, and nanodiamonds, have been embedded into responsive polymer nanogels, in order to integrate the unique electro-optical properties of carbon nanomaterials with the merits of nanogels into a single hybrid nanogel system for improvement of their applications in nanomedicine. A vast number of studies have been pursued to explore the applications of carbon-based hybrid nanogels in biomedical areas for biosensing, bioimaging, and smart drug carriers with combinatorial therapies and/or theranostic ability. New synthetic methods and structures have been developed to prepare carbon-based hybrid nanogels with versatile properties and functions. In this review, we summarize the latest developments and applications and address the future perspectives of these carbon-based hybrid nanogels in the biomedical field.

Interactions of Fullerene-Polyglycerol Sulfates at Viral and Cellular Interfaces

Understanding the mechanism of interactions of nanomaterials at biointerfaces is a crucial issue to develop new antimicrobial vectors. In this work, a series of water-soluble fullerene-polyglycerol sulfates (FPS) with different fullerene/polymer weight ratios and varying numbers of polyglycerol sulfate branches are synthesized, characterized, and their interactions with two distinct surfaces displaying proteins involved in target cell recognition are investigated. The combination of polyanionic branches with a solvent exposed variable hydrophobic core in FPS proves to be superior to analogs possessing only one of these features in preventing interaction of vesicular stomatitis virus coat glycoprotein (VSV-G) with baby hamster kidney cells serving as a model of host cell. Interference with L-selectin-ligand binding is dominated by the negative charge, which is studied by two assays: a competitive surface plasmon resonance (SPR)-based inhibition assay and the leukocyte cell (NALM-6) rolling on ligands under flow conditions. Due to possible intrinsic hydrophobic and electrostatic effects of synthesized compounds, pico- to nanomolar half maximal inhibitory concentrations (IC₅₀ ) are achieved. With their highly antiviral and anti-inflammatory properties, together with good biocompatibility, FPS are promising candidates for the future development towards biomedical applications.

Design, synthesis and biological evaluation of water-soluble per-O-methylated cyclodextrin-C60 conjugates as anti-influenza virus agents

The most common fullerene member C₆₀ displays many biological applications, such as, anticancer, human immunodeficiency virus and hepatitis C virus inhibitors, O₂ uptake inhibitor and vectors for drug and DNA. Nevertheless, the innate hydrophobicity of C₆₀ constrains its further development. We introduced cyclodextrins to enhance the water-solubility of C₆₀. Nine cyclodextrin-C₆₀ conjugates, including seven α-cyclodextrin-C₆₀ conjugates and two γ-cyclodextrin-C₆₀ conjugates, were designed and synthesized. All of these conjugates did not show obvious cytotoxicity. The anti-influenza virus activity of nine conjugates was assessed. Two γ-cyclodextrin-C₆₀ conjugates, which were relatively more water-soluble, exerted higher inhibition with IC₅₀ values of 87.73 μM and 75.06 μM, respectively, than seven α-cyclodextrin-C₆₀ conjugates.

Fullerenes in Biology and Medicine

Fullerenes and related carbon based derivatives have shown a growing relevance in biology and medicine, mainly due to the unique electronic and structural properties that make them excellent candidates for multiple functionalization. This review focuses on the most recent developments of fullerene derivatives for different biological applications.

Fullerene Polyglycerol Amphiphiles as Unimolecular Transporters

Due to their unique structure and properties, water-soluble fullerene derivatives are of great interest for various biomedical purposes. In this work, solution behavior, encapsulation and release properties, biocompatibility, and cellular uptake pathways of fullerene-polyglycerol amphiphiles (FPAs) with defined structures are investigated. The number of polyglycerol branches attached to the surface of fullerene affects the physicochemical properties of FPAs dramatically but not their cellular uptake. Release of encapsulated hydrophobic dyes from FPAs strongly depends on the number of their branches. Conjugation of a pH-sensitive dye to the FPAs as a probe showed that their self-assemblies are taken up through endocytotic pathways. It was observed that FPAs are able to transfer small molecules into cells both above and below their critical aggregation concentration. Taking advantage of the water solubility, biocompatibility, and transfer-ability of FPAs, they might find use as unimolecular carriers for future biomedical applications.

Characterization of New Cationic N,N-Dimethyl[70]fulleropyrrolidinium Iodide Derivatives as Potent HIV-1 Maturation Inhibitors

HIV-1 maturation can be impaired by altering protease (PR) activity, the structure of the Gag-Pol substrate, or the molecular interactions of viral structural proteins. Here we report the synthesis and characterization of new cationic N,N-dimethyl[70]fulleropyrrolidinium iodide derivatives that inhibit more than 99% of HIV-1 infectivity at low micromolar concentrations. Analysis of the HIV-1 life cycle indicated that these compounds inhibit viral maturation by impairing Gag and Gag-Pol processing. Importantly, fullerene derivatives 2a-c did not inhibit in vitro PR activity and strongly interacted with HIV immature capsid protein in pull-down experiments. Furthermore, these compounds potently blocked infectivity of viruses harboring mutant PR that are resistant to multiple PR inhibitors or mutant Gag proteins that confer resistance to the maturation inhibitor Bevirimat. Collectively, our studies indicate fullerene derivatives 2a-c as potent and novel HIV-1 maturation inhibitors.