High Amplification of the Antiviral Activity of Curcumin through Transformation into Carbon Quantum Dots

Assessing the efficacy of carbon nanodots derived from curcumin on infectious diseases

INTRODUCTION

The threat of new, emerging, and multidrug-resistant microbes is increasing which has created the necessity for new antimicrobials. In this regard, nanotechnology can be an alternative for the treatment of infectious microbes. Curcumin has been used since ancient times as antimicrobials; however, it has limitations due to its less aqueous solubility, bioavailability, and biocompatibility. This problem can be solved by curcumin-derived carbon nanodots, which are emerging antimicrobials of <10 nm size, water-soluble, biocompatible, less toxic, and fluorescent.

AREAS COVERED

The review discusses the application of curcumin-derived carbon nanodots against various pathogenic microbes including bacteria and dreaded viruses like SARS-CoV-2. In addition, the role of curcumin carbon nanodots in biolabelling of pathogenic microbes, mechanism of action, bioimaging, and therapy has been critically examined.

EXPERT OPINION

Carbon nanodots play an important role in combating pathogenic microbes by early diagnosis, bioimaging, nanocarrier for antimicrobial drugs, and therapy of infectious diseases. Curcumin carbon nanodots have already demonstrated their benefits of being water soluble, bioavailable, and biocompatible. However, more thorough research is needed to understand the efficacy and safety of curcumin carbon nanodots. In the future, curcumin-derived carbon nanodots can be used as alternative antimicrobial agents to fight microbial infections including multidrug-resistant microbes.

A new strategy of using low-dose caffeic acid carbon nanodots for high resistance to poorly differentiated human papillary thyroid cancer

Thyroid cancer is one of the most common endocrine malignancies in clinical practice. Traditional surgery and radioactive iodine ablation have poor treatment results for poorly differentiated thyroid cancer, and there is a risk of metastasis and recurrence. In this study, caffeic acid, a natural herbal extract with certain biological activity, has been as precursor to prepare new caffeic acid carbon nanodots via a one-step hydrothermal method. The caffeic acid carbon nanodots retains part of the structure and biological activity of caffeic acid, and have good biocompatibility, water solubility and stability. The construction of the carbon nanodots could effectively improve their bio-absorption rate and the efficacy. In vitro cell experiments showed that low-dose caffeic acid carbon nanodots had a significant inhibitory effect on poorly differentiated papillary thyroid carcinoma BCPAP cells. At low concentrations of 16 µg/mL, the inhibition rate of human thyroid cancer cells BCPAP was ~ 79%. The anti-tumor mechanism was predicted and verified by transcriptome, real-time quantitative PCR and western blot experiments. The caffeic acid carbon nanodots showed to simultaneously downregulate the expression of KRAS, p-BRAF, p-MEK1 and p-ERK1/2, the four continuous key proteins in a MAPK classical signaling pathway. In vivo experiments further confirmed the caffeic acid carbon nanodots could significantly inhibit the tumorigenicity of xenografts in papillary thyroid carcinoma at quite low doses. This piece of work provides a new nanomedicine and therapeutic strategy for highly resistant poorly differentiated papillary thyroid carcinoma.

Dry Heating of Curcumin in the Presence of Basic Salts Yields Anti-inflammatory Dimerization Products

Curcumin exerts some of its biological effects via degradation products formed by spontaneous oxidation at physiological, i.e., weakly basic, pH. Here, we analyzed products formed by dry heating of curcumin in the presence of a basic salt (sodium bicarbonate and others). Under the dry heating conditions employed, curcumin was completely consumed, yielding products entirely different from those obtained by autoxidative degradation in buffer. Bioassay-guided fractionation of the reaction mixture was used to identify and isolate compounds with anti-inflammatory activity in a cell-based assay. This provided two dimers of curcumin, dicurmins A and B, featuring a partly saturated naphthalene core that inhibited lipopolysaccharide-induced activation of NF-κB in RAW264.7 cells. Dicurmin A and B are unusual derivatives of curcumin lacking key functional moieties yet exhibit increased anti-inflammatory activity. The process of dry heating of polyphenols in the presence of a basic salt can serve as a novel approach to generating bioactive compounds.

Augmenting Neutrophil Extracellular Traps with Carbonized Polymer Dots: A Potential Treatment for Bacterial Sepsis

Sepsis is a life-threatening condition that can progress to septic shock as the body's extreme response to pathogenesis damages its own vital organs. Staphylococcus aureus (S. aureus) accounts for 50% of nosocomial infections, which are clinically treated with antibiotics. However, methicillin-resistant strains (MRSA) have emerged and can withstand harsh antibiotic treatment. To address this problem, curcumin (CCM) is employed to prepare carbonized polymer dots (CPDs) through mild pyrolysis. Contrary to curcumin, the as-formed CCM-CPDs are highly biocompatible and soluble in aqueous solution. Most importantly, the CCM-CPDs induce the release of neutrophil extracellular traps (NETs) from the neutrophils, which entrap and eliminate microbes. In an MRSA-induced septic mouse model, it is observed that CCM-CPDs efficiently suppress bacterial colonization. Moreover, the intrinsic antioxidative, anti-inflammatory, and anticoagulation activities resulting from the preserved functional groups of the precursor molecule on the CCM-CPDs prevent progression to severe sepsis. As a result, infected mice treated with CCM-CPDs show a significant decrease in mortality even through oral administration. Histological staining indicates negligible organ damage in the MRSA-infected mice treated with CCM-CPDs. It is believed that the in vivo studies presented herein demonstrate that multifunctional therapeutic CPDs hold great potential against life-threatening infectious diseases.

Carbonization of quercetin into nanogels: a leap in anticoagulant development

Quercetin, a flavonoid abundantly found in onions, fruits, and vegetables, is recognized for its pharmacological potential, especially for its anticoagulant properties that work by inhibiting thrombin and coagulation factor Xa. However, its clinical application is limited due to poor water solubility and bioavailability. To address these limitations, we engineered carbonized nanogels derived from quercetin (CNGsQur) using controlled pyrolysis and polymerization techniques. This led to substantial improvements in its anticoagulation efficacy, water solubility, and biocompatibility. We generated a range of CNGsQur by subjecting quercetin to varying pyrolytic temperatures and then assessed their anticoagulation capacities both in vitro and in vivo. Coagulation metrics, including thrombin clotting time (TCT), activated partial thromboplastin time (aPTT), and prothrombin time (PT), along with a rat tail bleeding assay, were utilized to gauge the efficacy. CNGsQur showed a pronounced extension of coagulation time compared to uncarbonized quercetin. Specifically, CNGsQur synthesized at 270 °C (CNGsQur270) exhibited the most significant enhancement in TCT, with a binding affinity to thrombin exceeding 400 times that of quercetin. Moreover, variants synthesized at 310 °C (CNGsQur310) and 290 °C (CNGsQur290) showed the most substantial delays in PT and aPTT, respectively. Our findings indicate that the degree of carbonization significantly influences the transformation of quercetin into various CNGsQur forms, each affecting distinct coagulation pathways. Additionally, both intravenous and oral administrations of CNGsQur were found to extend rat tail bleeding times by up to fivefold. Our studies also demonstrate that CNGsQur270 effectively delays and even prevents FeCl3-induced vascular occlusion in a dose-dependent manner in mice. Thus, controlled pyrolysis offers an innovative approach for generating quercetin-derived CNGs with enhanced anticoagulation properties and water solubility, revealing the potential for synthesizing self-functional carbonized nanomaterials from other flavonoids for diverse biomedical applications.

Theoretical Investigation of the Green-Synthesized Carbon-Based Nanomaterial Potential as Inhibitors of ACE2 for Blocking SARS-CoV-2 Binding

Since the emergence of SARS-CoV-2 in 2020, the world has faced a global pandemic, emphasizing the urgent need for effective treatments to combat COVID-19. This study explores the use of green-synthesized carbon-based nanomaterials as potential inhibitors of ACE2, a critical receptor for SARS-CoV-2 entry into host cells. Specifically, the study examines four carbon-based nanomaterials, namely, CD1, CD2, CD3, and CD4 in amino, graphitic, pyridinic, and pyrrolic forms, respectively, synthesized from curcumin, to investigate their binding affinity with ACE2. Molecular docking studies revealed that CD3 (pyridinic form) exhibited the highest binding affinity with ACE2, surpassing that of the control compound, curcumin. Notably, CD3 formed hydrophobic interactions and hydrogen bonds with key ACE2 residues, suggesting its potential to block the binding of SARS-CoV-2 to human cells. Moreover, molecular dynamics simulations demonstrated the stability of these ligand-ACE2 complexes, further supporting the promise of CD3 as an inhibitor. Quantum chemical analyses, including frontier molecular orbitals, natural bond orbital analysis, and the quantum theory of atoms in molecules, unveiled valuable insights into the reactivity and interaction strengths of these ligands. CD3 exhibited desirable chemical properties, signifying its suitability for therapeutic development. The study's findings suggest that green-synthesized carbon-based nanomaterials, particularly CD3, have the potential to serve as effective inhibitors of ACE2, offering a promising avenue for the development of treatments against COVID-19. Further experimental validation is warranted to advance these findings and establish new therapies for the ongoing global pandemic.

Carbon quantum dots of ginsenoside Rb1 for application in a mouse model of intracerebral Hemorrhage

After intracerebral hemorrhage (ICH) occurs, the overproduction of reactive oxygen species (ROS) and iron ion overload are the leading causes of secondary damage. Removing excess iron ions and ROS in the meningeal system can effectively alleviate the secondary damage after ICH. This study synthesized ginsenoside Rb1 carbon quantum dots (RBCQDs) using ginsenoside Rb1 and ethylenediamine via a hydrothermal method. RBCQDs exhibit potent capabilities in scavenging ABTS + free radicals and iron ions in solution. After intrathecal injection, the distribution of RBCQDs is predominantly localized in the subarachnoid space. RBCQDs can eliminate ROS and chelate iron ions within the meningeal system. Treatment with RBCQDs significantly improves blood flow in the meningeal system, effectively protecting dying neurons, improving neurological function, and providing a new therapeutic approach for the clinical treatment of ICH.

Current Advances in Japanese Encephalitis Virus Drug Development

Japanese encephalitis virus (JEV) belongs to the Flaviviridae family and is a representative mosquito-borne flavivirus responsible for acute encephalitis and meningitis in humans. Despite the availability of vaccines, JEV remains a major public health threat with the potential to spread globally. According to the World Health Organization (WHO), there are an estimated 69,000 cases of JE each year, and this figure is probably an underestimate. The majority of JE victims are children in endemic areas, and almost half of the surviving patients have motor or cognitive sequelae. Thus, the absence of a clinically approved drug for the treatment of JE defines an urgent medical need. Recently, several promising and potential drug candidates were reported through drug repurposing studies, high-throughput drug library screening, and de novo design. This review focuses on the historical aspects of JEV, the biology of JEV replication, targets for therapeutic strategies, a target product profile, and drug development initiatives.

Carbon quantum dots in bioimaging and biomedicines

Carbon quantum dots (CQDs) are gaining a lot more attention than traditional semiconductor quantum dots owing to their intrinsic fluorescence property, chemical inertness, biocompatibility, non-toxicity, and simple and inexpensive synthetic route of preparation. These properties allow CQDs to be utilized for a broad range of applications in various fields of scientific research including biomedical sciences, particularly in bioimaging and biomedicines. CQDs are a promising choice for advanced nanomaterials research for bioimaging and biomedicines owing to their unique chemical, physical, and optical properties. CQDs doped with hetero atom, or polymer composite materials are extremely advantageous for biochemical, biological, and biomedical applications since they are easy to prepare, biocompatible, and have beneficial properties. This type of CQD is highly useful in phototherapy, gene therapy, medication delivery, and bioimaging. This review explores the applications of CQDs in bioimaging and biomedicine, highlighting recent advancements and future possibilities to increase interest in their numerous advantages for therapeutic applications.

Multifunctional Carbon Dots for Biomedical Applications: Diagnosis, Therapy, and Theranostic

Designing suitable nanomaterials is an ideal strategy to enable early diagnosis and effective treatment of diseases. Carbon dots (CDs) are luminescent carbonaceous nanoparticles that have attracted considerable attention. Through facile synthesis, they process properties including tunable light emission, low toxicity, and light energy transformation, leading to diverse applications as optically functional materials in biomedical fields. Recently, their potentials have been further explored, such as enzyme-like activity and ability to promote osteogenic differentiation. Through refined synthesizing strategies carbon dots, a rich treasure trove for new discoveries, stand a chance to guide significant development in biomedical applications. In this review, the authors start with a brief introduction to CDs. By presenting mechanisms and examples, the authors focus on how they can be used in diagnosing and treating diseases, including bioimaging failure of tissues and cells, biosensing various pathogenic factors and biomarkers, tissue defect repair, anti-inflammation, antibacterial and antiviral, and novel oncology treatment. The introduction of the application of integrated diagnosis and treatment follows closely behind. Furthermore, the challenges and future directions of CDs are discussed. The authors hope this review will provide critical perspectives to inspire new discoveries on CDs and prompt their advances in biomedical applications.

Enhanced in vivo antiviral activity against pseudorabies virus through transforming gallic acid into graphene quantum dots with stimulation of interferon-related immune responses

With the urgent need for antiviral agents, antiviral materials with high biocompatibility and antiviral effects have attracted a lot of attention. In this study, gallic acid, a natural polyphenolic compound, was transformed into biocompatible graphene quantum dots (GAGQDs) which exhibit enhanced antiviral activity against pseudorabies virus (PRV). The as-prepared GAGQDs inhibit PRV proliferation with a 104-fold reduction in viral titers. Investigation of the antiviral mechanism revealed that GAGQDs inhibit the adsorption, invasion and replication of PRV infection. Treatment with GAGQDs regulates the expression levels of interferon-related antiviral proteins, including mitochondrial antiviral-signaling protein (MAVS), signal transducer and activator of transcription 1 (STAT1) and 2',5'-oligoadenylate synthetase 1 (OAS1), suggesting that GAGQDs can stimulate innate antiviral immune responses, resulting in enhanced antiviral effects. More importantly, GAGQD treatments alleviate clinical symptoms and reduce mortality in PRV-infected mice. Our results reveal the enhanced therapeutic effects of GAGQDs against PRV infection in vitro and in vivo, suggesting the potential of GAGQDs as a promising novel antiviral agent.

An Overview of the Potential of Food-Based Carbon Dots for Biomedical Applications

Food-based carbon dots (CDs) hold significant importance across various fields, ranging from biomedical applications to environmental and food industries. These CDs offer unique advantages over traditional carbon nanomaterials, including affordability, biodegradability, ease of operation, and multiple bioactivities. This work aims to provide a comprehensive overview of recent developments in food-based CDs, focusing on their characteristics, properties, therapeutic applications in biomedicine, and safety assessment methods. The review highlights the potential of food-based CDs in biomedical applications, including antibacterial, antifungal, antivirus, anticancer, and anti-immune hyperactivity. Furthermore, current strategies employed for evaluating the safety of food-based CDs have also been reported. In conclusion, this review offers valuable insights into their potential across diverse sectors and underscores the significance of safety assessment measures to facilitate their continued advancement and application.

Carbonized polymer dots derived from metformin and L-arginine for tumor cell membrane- and mitochondria-dual targeting therapy

Metformin has demonstrated antitumor potential in clinical studies; however, achieving optimal antitumor effects requires administering an extremely safe medication dose. To enhance the efficacy and reduce dosage requirements, we propose the creation of large-molecule drugs through the combination of small-molecule drugs. In this study, we developed novel polymer dots, referred to as MA-dots, with sizes of approximately 5 nm, featuring dual targeting capabilities for tumor cell membranes and mitochondria. MA-dots were synthesized using metformin and L-arginine via a rapid microwave-assisted method. Notably, the resulting MA-dots (with a half maximal inhibitory concentration (IC50) of 93.60 μg mL-1) exhibited more than a 12-fold increase in antitumor activity compared to the raw metformin material (IC50 = 1159.00 μg mL-1) over a 24-hour period. In addition, our MA-dots outperformed most metformin-derived nanodrugs in terms of antitumor efficacy. Furthermore, oral gavage treatment with MA-dots led to the suppression of A549 (lung cancer cell lines) tumor growth in vivo. Mechanistic investigations revealed that MA-dots bound to the large neutral amino acid transporter 1 (LAT1) proteins, which are overexpressed in malignant tumor cell membranes. Moreover, these MA-dots accumulated within the mitochondria, leading to increased production of reactive oxygen species (ROS), mitochondrial damage, and disruption of energy metabolism by modulating the 5'-adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway in tumor cells. This cascade of events triggers cell-cycle arrest and apoptosis. In summary, this study presented a rapid method for fabricating a novel nanoderivative, MA-dots, capable of both tumor targeting and exerting tumor-suppressive effects.

Carbon Dots Derived from Traditional Chinese Medicines with Bioactivities: A Rising Star in Clinical Treatment

In the field of carbon nanomaterials, carbon dots (CDs) have become a preferable choice in biomedical applications. Based on the concept of green chemistry, CDs derived from traditional Chinese medicines (TCMs) have attracted extensive attention, including TCM charcoal drugs, TCM extracts, and TCM small molecules. The design and preparation of CDs from TCMs (TCMs-CDs) can improve the inherent characteristics of TCMs, such as solubility, particle size distribution, and so on. Compared with other precursor materials, TCMs-CDs have outstanding intrinsic bioactivities and potential pharmacological effects. However, the research of TCMs-CDs in biomedicine is not comprehensive, and their mechanisms have not been understood deeply either. In this review, we will provide concise insights into the recent development of TCMs-CDs, with a major focus on their preparation, formation, precursors, and bioactivities. Then we will discuss the perfect transformation from TCMs to TCMs-CDs. Finally, we discuss the opportunities and challenges for the application of TCMs-CDs in clinical treatment.

The shape-dependent inhibitory effect of rhein/silver nanocomposites on porcine reproductive and respiratory syndrome virus

Traditional Chinese medicines (TCMs)/nanopreparations as viral antagonists exhibited a structure-function correlation, i.e., the differences in surface area/volume ratio caused by the variations in shape and size could result in different biochemical properties and biological activities, suggesting an important impact of morphology and structure on the antiviral activity of TCM-based nanoparticles. However, few studies paid attention to this aspect. Here, the effect of TCM-based nanoparticles with different morphologies on their antiviral activity was explored by synthesizing rhein/silver nanocomposites (Rhe@AgNPs) with spherical (S-Rhe/Ag) and linear (L-Rhe/Ag) morphologies, using rhein (an active TCM ingredient) as a reducing agent and taking its self-assembly advantage. Using porcine reproductive and respiratory syndrome virus (PRRSV) as a model virus, the inhibitory effects of S-Rhe/Ag and L-Rhe/Ag on PRRSV were compared. Results showed that the product morphology could be regulated by varying pH values, and both S- and L-Rhe/Ag exhibited good dispersion and stability, but with a smaller size for L-Rhe/Ag. Antiviral experiments revealed that Rhe@AgNPs could effectively inhibit PRRSV infection, but the antiviral effect was morphology-dependent. Compared with L-Rhe/Ag, S-Rhe/Ag could more effectively inactivate PRRSV in vitro and antagonize its adsorption, invasion, replication, and release stages. Mechanistic studies indicated that Rhe@AgNPs could reduce the production of reactive oxygen species (ROS) induced by PRRSV infection, and S-Rhe/Ag also had stronger ROS inhibitory effect. This work confirmed the inhibitory effect of Rhe@AgNPs with different morphologies on PRRSV and provided useful information for treating PRRSV infection with metal nanoparticles synthesized from TCM ingredients.

Porphyrin-derived carbon dots for an enhanced antiviral activity targeting the CTD of SARS-CoV-2 nucleocapsid

BACKGROUND

Since effective antiviral drugs for COVID-19 are still limited in number, the exploration of compounds that have antiviral activity against SARS-CoV-2 is in high demand. Porphyrin is potentially developed as a COVID-19 antiviral drug. However, its low solubility in water restricts its clinical application. Reconstruction of porphyrin into carbon dots is expected to possess better solubility and bioavailability as well as lower biotoxicity.

METHODS AND RESULTS

In this study, we investigated the antiviral activity of porphyrin and porphyrin-derived carbon dots against SARS-CoV-2. Through the in silico analysis and assessment using a novel drug screening platform, namely dimer-based screening system, we demonstrated the capability of the antivirus candidates in inhibiting the dimerization of the C-terminal domain of SARS-CoV-2 Nucleocapsid. It was shown that porphyrin-derived carbon dots possessed lower cytotoxicity on Vero E6 cells than porphyrin. Furthermore, we also assessed their antiviral activity on the SARS-CoV-2-infected Vero E6 cells. The transformation of porphyrin into carbon dots substantially augmented its performance in disrupting SARS-CoV-2 propagation in vitro.

CONCLUSIONS

Therefore, this study comprehensively demonstrated the potential of porphyrin-derived carbon dots to be developed further as a promisingly safe and effective COVID-19 antiviral drug.

Theranostics applications of quantum dots in regenerative medicine, cancer medicine, and infectious diseases

Quantum dots (QDs) have attracted attention for their application and commercialization in all industrial fields, including communications, displays, and solar cells, due to their excellent optical properties based on the quantum size effect. In recent years, the development of QDs that do not contain cadmium which is toxic to cells and living organisms, has progressed, and they have attracted considerable attention in the bio-imaging field for targeting molecules and cells. Furthermore, recently, the need for diagnostics and treatment at the single molecule and single cell level in the medical field has been increasing, and the application of QDs in the medical field is also accelerating. Therefore, this paper outlines the frontiers of diagnostic and therapeutic applications (theranostics) of QDs, especially in advanced medical fields such as regenerative medicine, oncology, and infectious diseases.

Curcumin-derived carbon-dots as a potential COVID-19 antiviral drug

Even entering the third year of the COVID-19 pandemic, only a small number of COVID-19 antiviral drugs are approved. Curcumin has previously shown antiviral activity against SARS-CoV-2 nucleocapsid, but its poor bioavailability limits its clinical uses. Utilizing nanotechnology structures, curcumin-derived carbon-dots (cur-CDs) were synthesized to increase low bioavailability of curcumin. In-silico analyses were performed using molecular docking, inhibition of SARS-CoV-2 nucleocapsid C-terminal domain (N-CTD) and antiviral activity were assessed in dimer-based screening system (DBSS) and in vitro respectively. Curcumin bound with the N-CTD at ΔG = -7.6 kcal/mol, however modifications into cur-CDs significantly improved the binding affinity and %interaction. Cur-CDs also significantly increased protection against SARS-CoV-2 in both DBSS and in vitro at MOI = 0.1. This study demonstrated the effect of post-infection treatment of curcumin and novel curcumin-derived carbon-dots on SARS-CoV-2 N-CTD dimerization. Further investigation on pre-infection and in-vivo treatment of curcumin and cur-CDs are required for a comprehensive understanding on the carbon-dots enhanced antiviral activity of curcumin against SARS-CoV-2.

Carbon nanodots constructed by ginsenosides and their high inhibitory effect on neuroblastoma

BACKGROUND

Neuroblastoma is one of the common extracranial tumors in children (infants to 2 years), accounting for 8 ~ 10% of all malignant tumors. Few special drugs have been used for clinical treatment currently.

RESULTS

In this work, herbal extract ginsenosides were used to synthesize fluorescent ginsenosides carbon nanodots via a one-step hydrothermal method. At a low cocultured concentration (50 µg·mL^- 1) of ginsenosides carbon nanodots, the inhibition rate and apoptosis rate of SH-SY5Y cells reached ~ 45.00% and ~ 59.66%. The in vivo experiments showed tumor volume and weight of mice in ginsenosides carbon nanodots group were ~ 49.81% and ~ 34.14% to mice in model group. Since ginsenosides were used as sole reactant, ginsenosides carbon nanodots showed low toxicity and good animal response.

CONCLUSION

Low-cost ginsenosides carbon nanodots as a new type of nanomedicine with good curative effect and little toxicity show application prospects for clinical treatment of neuroblastoma. It is proposed a new design for nanomedicine based on bioactive carbon nanodots, which used natural bioactive molecules as sole source.

In Vitro and Silico Studies on the N-Doped Carbon Dots Potential in ACE2 Expression Modulation

The alteration of ACE2 expression level, which has been studied in many diseases, makes the topic of ACE2 inducer potential crucial to be explored. The ACE2 inducer could further be designed to control the ACE2 expression level, which is appropriate to a specific case. An in vitro study of well-characterized carbon dots (CDs), made from citric acid and urea, was performed to determine their ability to modulate the ACE2 receptor. Gene expression of ACE2 was quantified using concentrations adjusted for IC50 results from CDs viability assays in HEK 293 and A549 cell lines. RT-qPCR was used to assess the expression of the ACE2 gene and its induction effect in normal cell lines (HEK-293A). According to the results of the tests, ACE2 is expressed in HEK-293A cell lines, and diminazene aceturate can increase ACE2 expression. The effect of CDs on ACE2 gene expression was further examined on the cell lines that had previously been induced with diminazene aceturate, which resulted in upregulation of the ACE2 expression level. An in silico study has been done by using a molecular docking approach. The molecular docking results show that CDs can make strong interactions with ACE2 amino acid residues through hydrophobic interaction, π-π interaction, π-cation interaction, and ionic interaction.

Glycyrrhizic Acid-Based Carbonized Dots Boost Antiviral Activity against Influenza A Virus via Multisite Inhibition Mechanisms

Influenza A virus (IVA) has been continuously causing pandemics in several animal hosts and has become a worldwide public health threat. Currently, antiviral drugs have become associated with a lot of side effects and limited activity against emerging drug-resistant influenza viruses. Therefore, the development of novel antiviral drugs is of great importance. In this study, we synthesized a kind of carbon dots (CDs) with high dispersibility from glycyrrhizic acid (GA) using a simple dry heating method. Compared with glycyrrhizic acid alone, GA-CDs exhibit superior solubility and significantly improve the antiviral property against IVA. Investigation of the mechanism revealed that GA-CDs act against IVA mainly by inhibiting viral internalization, replication of the viral genome, neuraminidase activity, and host inflammatory responses. More importantly, in a mouse model, GA-CDs can significantly alleviate the clinical symptoms and decrease mortality and lung viral titers. In vitro and in vivo experiments demonstrate that GA-CDs possess extraordinary therapeutic effects; therefore, we propose that GA-CDs may be a promising alternative therapy for IVA infection.

Structure-Property-Activity Relationships in Carbon Dots

Carbon dots (CDs) are one of the most versatile nanomaterials discovered in the 21st century. They possess many properties and thus hold potentials in diverse applications. While an increasing amount of attention has been given to these novel nanoparticles, the broad scientific community is actively engaged in exploring their limits. Recent studies on the fractionalization and assembly of CDs further push the limits beyond just CDs and demonstrate that CDs are both a mixture of heterogeneous fractions and promising building blocks for assembly of large carbon-based materials. With CDs moving forward toward both microscopic and macroscopic levels, a good understanding of the structure-property-activity relationships is essential to forecasting the future of CDs. Hence, in this Perspective, structure-property-activity relationships are highlighted based on the repeatedly verified findings in CDs. In addition, studies on CD fractionalization and assembly are briefly summarized in this Perspective. Eventually, these structure-property-activity relationships and controllability are essential for the development of CDs with desired properties for various applications especially in photochemistry, electrochemistry, nanomedicine, and surface chemistry. In summary, in our opinion, since 2004 until the present, history has witnessed a great development of CDs although there is still some room for more studies. Also, considering many attractive properties, structure-property-activity relationships, and the building block nature of CDs, a variety of carbon-based materials of interest can be constructed from CDs with control. They can help reduce blind trials in the development of carbon-based materials, which is of great significance in materials science, chemistry, and any fields related to the applications.

Carrier-free nanoplatforms from natural plants for enhanced bioactivity

BACKGROUND

Natural plants as well as traditional Chinese medicine have made outstanding contributions to the health and reproduction of human beings and remain the basis and major resource for drug innovation. Carrier-free nanoplatforms completely self-assembled by pure molecules or therapeutic components have attracted increasing attention due to their advantages of improved pharmacodynamics/pharmacokinetics, reduced toxicity, and high drug loading. In recent years, carrier-free nanoplatforms produced by self-assembly from natural plants have contributed to progress in a variety of therapeutic modalities. Notably, these nanoplatforms based on the interactions of components from different natural plants improve efficiency and depress toxicity.

AIM OF REVIEW

In this review, different types of self-assembled nanoplatforms are first summarized, mainly including nanoassemblies of pure small molecules isolated from different plants, extracellular vesicles separated from fresh plants, charcoal nanocomponents obtained from charred plants, and nanoaggregates from plants formulae decoctions. Key Scientific Concepts of Review: We mainly focus on composition, self-assembly mechanisms, biological activity and modes of action. Finally, a future perspective of existing challenges with respect to the clinical application of plant-based carrier-free nanoplatforms is discussed, which may be instructive to further develop effective carrier-free nanoplatforms from natural plants in the future.

Progress on Applying Carbon Dots for Inhibition of RNA Virus Infection

Viral infection is a globally leading health issue. Annually, new lethal RNA viruses unexpectedly emerged and mutated threatening health and safety. Meanwhile, it is urgent to explore novel antiviral agents, which, however, takes years to be clinically available. Nonetheless, the development of carbon dots (CDs) in the past 20 years has exhibited their vast application potentials and revealed their promising capacity as future antiviral agents considering their versatile properties and significant antiviral responses. Thus, CDs have been widely investigated as an alternative of traditional chemotherapy for inhibiting viral infection and replication in vitro. Meanwhile, attempts to apply CDs to in vivo systems are in high demand. In this review, recent developments of CDs-based antiviral therapies are systematically summarized. Furthermore, the role of CDs in photodynamic inactivation to kill viruses or bacteria is briefly discussed.

Carbon dots for multicolor cell imaging and ultra-sensitive detection of multiple ions in living cells: One Stone for multiple Birds

Given the significant impact of ions on environment pollution and human health, it is urgently needed to establish effective and convenient ion detection approaches, particularly in living cells. In this paper, we constructed multicolor N-doped-carbon dots (mPD-CDs) by facile one-step hydrothermal carbonization of m-phenylenediamine (mPD). mPD-CDs were successfully deployed for multicolor cellular imaging for animal cells, fungi, and bacteria in a wash-free way with high photostability and satisfactory biocompability. Moreover, mPD-CDs can be used as a fluorescent sensing probe for ultrasensitive detection of both iodide ion (I^-) and typical heavy metals such as cadmium (Cd²⁺), copper (Cu²⁺), mercury (Hg²⁺), gadolinium (Gd³⁺), ferrous ion (Fe²⁺), Zinc (Zn²⁺), and ferric ion (Fe³⁺). This is the first report using CDs as optical sensing probe for the detection of Gd³⁺, and for detection of Fe³⁺ with fluorescence "turn on". More significantly, with these versatile and fascinating properties, we applied mPD-CDs for intracellular ion detection in living cells like Hep G2 and S. cerevisiae, and zebra fish. Altogether, mPD-CDs displayed great potential for multicolor cell imaging and the multiple ion detection in vitro and in vivo, presenting a promising strategy for in-situ ultrasensitive sensing of multiple metal ions in the environment and the biological systems.

Protease-responsive hydrogel, cross-linked with bioactive curcumin-derived carbon dots, encourage faster wound closure

The pharmacological effects of curcumin can be ascribed to its dose-dependent activity. Therapeutic application of curcumin is hindered by its poor solubility and low bioavailability. Carbon dots are gaining attention in biomedical applications in view of their unique photo-physical properties. Some carbon dots derived from bioactive molecules have shown superior activity than the parent compound. With an aim to address the limitations of curcumin, herein we compared the wound healing activity of curcumin-derived carbon dots (CurCD) with curcumin. The improved solubility and stability of CurCD, combined with its superior proliferative, proangiogenic and anti-bacterial activity suggested that CurCD would be more beneficial than curcumin in wound healing. To enable the sustained release of CurCD at the wound site, a protease-responsive hydrogel (GHCD) was prepared with CurCD acting as a cross-linker. A comparative study using a skin excision model revealed that GHCD supported faster wound closure with improved angiogenesis and complete restoration of the epithelium. Apart from the establishment of CurCD as a wound healing agent, the study provides a novel carbon dot based approach for molecules with limitations of solubility and bioavailability.

Reconnoitering the Therapeutic Role of Curcumin in Disease Prevention and Treatment: Lessons Learnt and Future Directions

Turmeric is a plant with a very long history of medicinal use across different cultures. Curcumin is the active part of turmeric, which has exhibited various beneficial physiological and pharmacological effects. This review aims to critically appraise the corpus of literature associated with the above pharmacological properties of curcumin, with a specific focus on antioxidant, anti-inflammatory, anticancer and antimicrobial properties. We have also reviewed the different extraction strategies currently in practice, highlighting the strengths and drawbacks of each technique. Further, our review also summarizes the clinical trials that have been conducted with curcumin, which will allow the reader to get a quick insight into the disease/patient population of interest with the outcome that was investigated. Lastly, we have also highlighted the research areas that need to be further scrutinized to better grasp curcumin’s beneficial physiological and medicinal properties, which can then be translated to facilitate the design of better bioactive therapeutic leads.

Quantum dots against SARS-CoV-2: diagnostic and therapeutic potentials

The application of quantum dots (QDs) for detecting and treating various types of coronaviruses is very promising, as their low toxicity and high surface performance make them superior among other nanomaterials; in conjugation with fluorescent probes they are promising semiconductor nanomaterials for the detection of various cellular processes and viral infections. In view of the successful results for inhibiting SARS-CoV-2, functional QDs could serve eminent role in the growth of safe nanotherapy for the cure of viral infections in the near future; their large surface areas help bind numerous molecules post-synthetically. Functionalized QDs with high functionality, targeted selectivity, stability and less cytotoxicity can be employed for highly sensitive co-delivery and imaging/diagnosis. Besides, due to the importance of safety and toxicity issues, QDs prepared from plant sources (e.g. curcumin) are much more attractive, as they provide good biocompatibility and low toxicity. In this review, the recent developments pertaining to the diagnostic and inhibitory potentials of QDs against SARS-CoV-2 are deliberated including important challenges and future outlooks. © 2022 Society of Chemical Industry (SCI).

Curcumin and Its Analogs as a Therapeutic Strategy in Infections Caused by RNA Genome Viruses

The use of natural resources for the prevention and treatment of diseases considered fatal to humanity has evolved. Several medicinal plants have nutritional and pharmacological potential in the prevention and treatment of viral infections, among them, turmeric, which is recognized for its biological properties associated with curcuminoids, mainly represented by curcumin, and found mostly in rhizomes. The purpose of this review was to compile the pharmacological activities of curcumin and its analogs, aiming at stimulating their use as a therapeutic strategy to treat infections caused by RNA genome viruses. We revisited its historical application as an anti-inflammatory, antioxidant, and antiviral agent that combined with low toxicity, motivated research against viruses affecting the population for decades. Most findings concentrate particularly on arboviruses, HIV, and the recent SARS-CoV-2. As one of the main conclusions, associating curcuminoids with nanomaterials increases solubility, bioavailability, and antiviral effects, characterized by blocking the entry of the virus into the cell or by inhibiting key enzymes in viral replication and transcription.

Antiviral Biodegradable Food Packaging and Edible Coating Materials in the COVID-19 Era: A Mini-Review

With the onset of the COVID-19 pandemic in late 2019, and the catastrophe faced by the world in 2020, the food industry was one of the most affected industries. On the one hand, the pandemic-induced fear and lockdown in several countries increased the online delivery of food products, resulting in a drastic increase in single-use plastic packaging waste. On the other hand, several reports revealed the spread of the viral infection through food products and packaging. This significantly affected consumer behavior, which directly influenced the market dynamics of the food industry. Still, a complete recovery from this situation seems a while away, and there is a need to focus on a potential solution that can address both of these issues. Several biomaterials that possess antiviral activities, in addition to being natural and biodegradable, are being studied for food packaging applications. However, the research community has been ignorant of this aspect, as the focus has mainly been on antibacterial and antifungal activities for the enhancement of food shelf life. This review aims to cover the different perspectives of antiviral food packaging materials using established technology. It focuses on the basic principles of antiviral activity and its mechanisms. Furthermore, the antiviral activities of several nanomaterials, biopolymers, natural oils and extracts, polyphenolic compounds, etc., are discussed.

Recent advances in carbon quantum dots for virus detection, as well as inhibition and treatment of viral infection

In the last decade, carbon quantum dots (CQDs), as a novel class of carbon-based nanomaterials, have received increasing attention due to their distinct properties. CQDs are ultimately small nanoparticles with an average size below 10 nm, possessing high water solubility, alluring photoluminescence, photostability, excellent biocompatibility, low/none toxicity, environmental friendliness, and high sustainability, etc. In history, there are intermittent threats from viruses to humans, animals and plants worldwide, resulting in enormous crises and impacts on our life, environment, economy and society. Some recent studies have unveiled that certain types of CQDs exhibited high and potent antiviral activities against various viruses such as human coronavirus, arterivirus, norovirus and herpesvirus. Moreover, they have been successfully explored and developed for different virus detections including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This article exclusively overviews and discusses the recent progress of designing, synthesizing, modifying/functionalizing and developing CQDs towards effective virus detection as well as the inhibition and treatment of viral infection. Their mechanisms and applications against various pathogenic viruses are addressed. The latest outcomes for combating the coronavirus disease 2019 (COVID-19) utilizing CQDs are also highlighted. It can be envisaged that CQDs could further benefit the development of virus detectors and antiviral agents with added broad-spectrum activity and cost-effective production.

Vinblastine Loaded On Graphene Quantum Dots And Its Anticancer Applications

AIMS

The aim of our work is to load Vinblastine drug loaded on graphene quantum dots to improve its cytotoxicity on cancer cells and reduce it on normal cell in the composites. Moreover, GQDs-Vin composite significantly inhibited the tumor growth in animals.

METHODS

GQDs-Vin composites were prepared by homogenization of GQDs and Vin solutions. The loading of Vin on GQDs in the composites were characterized by FTIR, PL, UV-vis spectra, and TEM. The cytotoxicity of GQDs, Vin, and GQDs-Vin composites was investigated on the Hela, HGC-27, A549, MCF-7, CCF-STTG1 cells and Vero by in vitro and in vivo methods. The difference in cellular structure and organelles in mice's livers in comparison between control group and GQDs-Vin (1:5) groups was characterized by TEM.

RESULTS

The diameter of the nanoparticles of GQDs-Vin composites in weight ratios 1:1, 1:3 and 1:5 w/w of 50-70 nm, 100-150 nm and ∼500nm, respectively, is larger than that of GQDs of 10-50nm. The in vitro results showed that GQDs not only improved the cytotoxicity of Vin to cancer cells, but also decreased its cytotoxicity towards normal cells in the composites. The GQDs-Vin (1:5) composite exhibited a stronger tumor inhibition effect than Vin alone. The morphology of mice's livers showed the absence GQDs-Vin nanoparticles in the mice's livers suggests the lack of storage and the leakage from the liver without any toxicity.

CONCLUSIONS

Results of the improved cytotoxicity of GQDs-Vin composite on cancer cells, its reduced cytotoxicity on normal cell and the significant inhibition on tumor growth of GQDs-Vin composite compared with Vin and GQDs alone may indicate a synergistic effect of Vin and GQDs in their composites for anticancer application.

Orange-red to NIR emissive carbon dots for antimicrobial, bioimaging and bacteria diagnosis

Antimicrobial photodynamic therapy (aPDT) has become a popular technology for the treatment of bacterial infections. The development of antimicrobial agents combining diagnosis and treatment remains a major challenge. Herein, curcumin carbon quantum dots (Cur-NRCQDs) with antibacterial and imaging effects were synthesized using a hydrothermal method. The fluorescence absorption range of the Cur-NRCQDs in aqueous solution was 555 to 850 nm, showing orange-red to near infrared (NIR) fluorescence, and its maximum emission wavelength was 635 nm. At the same time, Cur-NRCQDs improved the efficiency of Cur as the photosensitizer (PS), showed good storage and light stability, and enhanced the efficiency of reactive oxygen (ROS) generation and antibacterial activity. Under the irradiation of a xenon lamp, Cur-NRCQDs inactivated 100% Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) at concentrations of 10 and 15 μM, respectively. The possible reason for this was that under PDT, the ROS produced by the Cur-NRCQDs destroyed the integrity of the cell membrane, resulting in leakage of the contents. In addition, the Cur-NRCQDs showed good cell compatibility, as they can also enter bacteria and cells for imaging, so they can be employed for the detection of bacteria and cell tissues. Therefore, Cur-NRCQDs are an ideal candidate material for aPDT treatment and fluorescent bioimaging.

Curcumin assists anti-EV71 activity of IFN-α by inhibiting IFNAR1 reduction in SH-SY5Y cells

Background and aim

Enterovirus 71(EV71) can cause severe hand, foot, and mouth disease (HFMD) with brain tissue involvement. Few effective anti-EV71 drugs are presently available in clinical practice. Interferon-α (IFN-α) was ineffective while Curcumin was effective in restricting EV71 replication in non-neuronal cells. Ubiquitin–proteasome-mediated degradation of interferon-alpha receptor 1 (IFNAR1) protein contributes to IFN-α resistance. Current study aimed to determine synergistic inhibition of EV71 by Curcumin and IFN-α in human neuroblastoma SH-SY5Y cells.

Methods

SH-SY5Y cells were infected with mock-/Curcumin-pre-incubated EV71 or transfected with plasmid containing interferon-stimulated response element (ISRE) or mRNA containing viral internal ribosomal entry site (IRES) following by post-treatment with Curcumin with or without IFN-α. Supernatant IFN-α/β was detected by ELISA. ISRE, IRSE, proteasome and deubiquitinating activity were measured by luciferase assay. EV71 RNA and viral protein or IFNAR1 were determined by qPCR and western blot, respectively.

Results

EV71 flailed to completely block IFN-α/β production but inhibited IFN-α signal. Curcumin only slightly inhibited EV71 proliferation without modulating virus attachment and internalization. However, Curcumin addition restored IFN-α-mediated ISRE activity thus significantly inhibiting EV71 replication. Furthermore, EV71 also reduced IFNAR1 protein with proteasome-dependence in SH-SY5Y cells, which can be reversed by Curcumin addition with the evidence that it lowered proteasome activity.

Conclusion

These data demonstrate that Curcumin assists anti-EV71 activity of IFN-α by inhibiting IFNAR1 reduction via ubiquitin–proteasome disruption in SH-SY5Y cells.

Phytochemically Derived Zingerone Nanoparticles Inhibit Cell Proliferation, Invasion and Metastasis in Human Oral Squamous Cell Carcinoma

Due to its aggressiveness and high mortality rate, oral cancer still represents a tough challenge for current cancer therapeutics. Similar to other carcinomas, cancerous invasion and metastasis are the most important prognostic factors and the main obstacles to therapy for human oral squamous cell carcinoma (OSCC). Fortunately, with the rise of the nanotechnical era and innovative nanomaterial fabrication, nanomaterials are widely used in biomedicine, cancer therapeutics, and chemoprevention. Recently, phytochemical substances have attracted increasing interest as adjuvants to conventional cancer therapy. The ginger phenolic compound zingerone, a multitarget pharmacological and bioactive phytochemical, possesses potent anti-inflammatory, antioxidant, and anticancer activities. In our previous study, we generated phytochemically derived zingerone nanoparticles (NPs), and documented their superior antitumorigenic effect on human hepatoma cells. In the present study, we further investigated the effects of zingerone NPs on inhibiting the invasiveness and metastasis of human OSCC cell lines. Zingerone NPs elicited significant cytotoxicity in three OSCC cell lines compared to zingerone. Moreover, the lower dose of zingerone NPs (25 µM) markedly inhibited colony formation and colony survival by at least five-fold compared to zingerone treatment. Additionally, zingerone NPs significantly attenuated cell motility and invasiveness. In terms of the signaling mechanism, we determined that the zingerone NP-mediated downregulation of Akt signaling played an important role in the inhibition of cell viability and cell motility. Zingerone NPs inhibited matrix metalloproteinase (MMP) activity, which was highly correlated with the attenuation of cell migration and cell invasion. By further detecting the roles of zingerone NPs in epithelial-mesenchymal transition (EMT), we observed that zingerone NPs substantially altered the levels of EMT-related markers by decreasing the levels of the mesenchymal markers, N-cadherin and vimentin, rather than the epithelial proteins, ZO-1 and E-cadherin, compared with zingerone. In conclusion, as novel and efficient phytochemically derived nanoparticles, zingerone NPs may serve as a potent adjuvant to protect against cell invasion and metastasis, which will provide a beneficial strategy for future applications in chemoprevention and conventional therapeutics in OSCC treatment.

Protective Effects of Carbon Dots Derived from Armeniacae Semen Amarum Carbonisata Against Acute Lung Injury Induced by Lipopolysaccharides in Rats

Introduction

The charcoal processed product of Armeniacae Semen Amarum (ASA), ASA Carbonisata (ASAC), has long been used for its anti-inflammatory effects. However, the material basis and mechanism of action of ASAC remain unclear.

Aim

To explore the anti-inflammatory effects of Armeniacae Semen Amarum Carbonisata-derived carbon dots (ASAC-CDs).

Methods

The physicochemical properties of ASAC-CDs including morphology, optical properties, functional groups were characterized by a series of methods, mainly including electron microscopy, optical technology and X-ray photoelectron spectroscopy. The anti-inflammatory effect of ASAC-CDs was evaluated and confirmed using acute lung injury (ALI) induced by lipopolysaccharides (LPS) in rats.

Results

The ASAC-CDs ranged from 1.5 to 5.5 nm in diameter, with a quantum yield of 3.17%. ASAC-CDs alleviated LPS-induced inflammation, as demonstrated by reducing the levels of IL-6, IL-1β and TNF-α and increasing the contents of IL-10 in rat serum. More interestingly, ASAC-CDs reduce the content of MDA and MPO and increase the activity of SOD and the content of GSH, indicating the antioxidant activity of ASAC-CDs.

Conclusion

These results demonstrate the remarkable anti-inflammatory effects of ASAC-CDs against ALI induced by LPS, which provide an important basis for the application of ASAC-CDs in clinical anti-pneumonia, and lay an experimental foundation for the research and development of novel nano-drugs.

Multifunctional carbonized nanogels to treat lethal acute hepatopancreatic necrosis disease

Background

Shrimp aquaculture has suffered huge economic losses over the past decade due to the outbreak of acute hepatopancreatic necrosis disease (AHPND), which is mainly caused by the bacteria Vibrio parahaemolyticus (V. parahaemolyticus) with the virulence pVA1 plasmid, which encodes a secretory photorhabdus insect-related (Pir) toxin composed of PirA and PirB proteins. The Pir toxin mainly attacks the hepatopancreas, a major metabolic organ in shrimp, thereby causing necrosis and loss of function. The pandemic of antibiotic-resistant strains makes the impact worse.

Methods

Mild pyrolysis of a mixture of polysaccharide dextran 70 and the crosslinker 1,8-diaminooctane at 180 ℃ for 3 h to form carbonized nanogels (DAO/DEX-CNGs) through controlled cross-linking and carbonization. The multifunctional therapeutic CNGs inherit nanogel-like structures and functional groups from their precursor molecules.

Results

DAO/DEX-CNGs manifest broad-spectrum antibacterial activity against Vibrio parahaemolyticus responsible for AHPND and even multiple drug-resistant strains. The polymer-like structures and functional groups on graphitic-carbon within the CNGs exhibit multiple treatment effects, including disruption of bacterial membranes, elevating bacterial oxidative stress, and neutralization of PirAB toxins. The inhibition of Vibrio in the midgut of infected shrimp, protection of hepatopancreas tissue from Pir toxin, and suppressing overstimulation of the immune system in severe V. parahaemolyticus infection, revealing that CNGs can effectively guard shrimp from Vibrio invasion. Moreover, shrimps fed with DAO/DEX-CNGs were carefully examined, such as the expression of the immune-related genes, hepatopancreas biopsy, and intestinal microbiota. Few adverse effects on shrimps were observed.

Conclusion

Our work proposes brand-new applications of multifunctional carbon-based nanomaterials as efficient anti-Vibrio agents in the aquatic industry that hold great potential as feed additives to reduce antibiotic overuse in aquaculture.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01194-8.

Antiproliferative and ROS Regulation Activity of Photoluminescent Curcumin-Derived Nanodots

Recently, various types of nanomaterials have been employed to design delivery vehicles for curcumin to address the problems of poor bioavailability, low aqueous solubility, and rapid metabolism. The present study focuses on a direct one-pot synthesis of curcumin-derived nanoparticles and exploits their potential therapeutic properties in cancer cells in vitro without additional delivery vehicles. The nanoparticles, named E-Curc-dots, are synthesized using three precursor molecules, ethylenediamine (EDA), curcumin, and citric acid. The structure, composition, and physichemical properties of the nanodots are characterized and identified by employing spectroscopic and microscopic techniques. The as-synthesized E-Curc-dots exhibit bright blue photoluminescence due to the incorporation of nitrogen from the EDA precursor molecule. The characterization studies show a uniform distribution of dots with an average size of 4.6 ± 1.7 nm and, notably, that the dots retain some of the major characteristics of native curcumin with much improved water solubility and bioavailability. The E-Curc-dots show antioxidation activity at low concentrations (<0.08 mg/mL) with low levels of reactive oxygen species (ROS) generation, i.e., 82% of the ROS level in cells without treatment for A549 cells; however, at high concentrations, the nanodots exhibit a pro-oxidant effect on both the cancer cells (A549) and normal cells (EA.hy926) by inducing more ROS generation and dose-dependent cytotoxicity. The E-Curc-dots demonstrate higher cytotoxicity toward cancer cells compared to native curcumin at a lower concentration. The results indicate the efficacy of E-Curc-dots as an antiproliferative and ROS regulator with the ability of cellular bioimaging.

Carbon dots for virus detection and therapy

Recent experience with the COVID-19 pandemic should be a lesson learnt with respect to the effort we have to invest in the development of new strategies for the treatment of viral diseases, along with their cheap, easy, sensitive, and selective detection. Since we live in a globalized world where just hours can play a crucial role in the spread of a virus, its detection must be as quick as possible. Thanks to their chemical stability, photostability, and superior biocompatibility, carbon dots are a kind of nanomaterial showing great potential in both the detection of various virus strains and a broad-spectrum antiviral therapy. The biosensing and antiviral properties of carbon dots can be tuned by the selection of synthesis precursors as well as by easy post-synthetic functionalization. In this review, we will first summarize current options of virus detection utilizing carbon dots by either electrochemical or optical biosensing approaches. Secondly, we will cover and share the up-to-date knowledge of carbon dots' antiviral properties, which showed promising activity against various types of viruses including SARS-CoV-2. The mechanisms of their antiviral actions will be further adressed as well. Finally, we will discuss the advantages and distadvantages of the use of carbon dots in the tangled battle against viral infections in order to provide valuable informations for further research and development of new virus biosensors and antiviral therapeutics.

Role of nanotechnology in facing SARS-CoV-2 pandemic: Solving crux of the matter with a hopeful arrow in the quiver

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a positive-sense single-stranded RNA virus species with a zoonotic origin and responsible for the coronavirus disease 2019(COVID-19). This novel virus has an extremely high infectious rate, which occurs through the contact of contaminated surfaces and also by cough, sneeze, hand-to-mouth-to-eye contact with an affected person. The progression of infection, which goes beyond complications of pneumonia to affecting other physiological functions which cause gastrointestinal, Renal, and neurological complication makes this a life threatening condition. Intense efforts are going across the scientific community in elucidating various aspects of this virus, such as understanding the pathophysiology of the disease, molecular biology, and cellular pathways of viral replication. We hope that nanotechnology and material science can provide a significant contribution to tackle this problem through both diagnostic and therapeutic strategies. But the area is still in the budding phase, which needs urgent and significant attention. This review provides a brief idea regarding the various nanotechnological approaches reported for managing COVID-19 infection. The nanomaterials recently said to have good antiviral activities like Carbon nanotubes (CNTs) and quantum dots (QDs) were also discussed since they are also in the emerging stage of attaining research interest regarding antiviral applications.

Synthesis of carbon dots with antiphage activity using caffeic acid

Recent studies on preservation properties in the field of materials science suggest that a newly synthesized material can retain the biological properties of the raw material. Still, further study is necessary since these features critically influence research at the intersection of materials science and biology, and could provide a unique research direction for the synthesis of new materials. Thus, caffeic acid (CA) is used as a raw material to synthesize novel carbon quantum dots (CA-CDs) using a simple and rapid hydrothermal method. CA-CDs exhibit antiphage and antibacterial activities. Using three types of phages as models, it is confirmed that CA-CDs inhibit phage proliferation. The viral titres decline by 4, 5, or 6 orders of magnitude, and CA-CDs display potential universal antiphage ability; the mechanism suggests that the CA-CDs could change the protein structure of these phages and impact the phage adsorption stage leading to loss of infectivity. Meanwhile, the antibacterial activity is retained in CA-CDs, significantly inhibiting the growth of Gram-positive bacteria; this also reveals the preservation properties of CA-CDs. CA-CDs synthesized from CA, does not only expand the range of antiviral activity but also increases its many unique optical properties as a carbon dot material. This finding is meaningful in order to promote the development of new CDs with remarkable biological activity and acts as a basis for future scientific research on novel and alternative antiviral treatments.

Bioenzyme-responsive L-arginine-based carbon dots: the replenishment of nitric oxide for nonpharmaceutical therapy

Nitric oxide (NO) is a short-lived, bioactive gas that has been found to have affinitive effects on cardiovascular diseases as well as cancer biology, while NO deficiency may cause serious pathological responses. The existing chemically-synthesized NO donors have inevitable systemic toxicity and cannot be released adaptively. Hence, L-arginine, an endogenous NO precursor, merits investigation as a natural efficient NO donor. Herein, we designed amino acid-doped L-arginine CDs-based bioenzyme-responsive NO donors, which could adaptively replenish NO/ONOO^- in response to different microenvironments. Our results indicated the mechanism of the NO/ONOO^- supplementation of L-arginine-based CDs and their potential for nonpharmaceutical gas-involving theranostics for the first time.

Advanced Nanomaterials for Preparedness Against (Re-)Emerging Viral Diseases

While the coronavirus disease (COVID-19) accounts for the current global pandemic, the emergence of other unknown pathogens, named "Disease X," remains a serious concern in the future. Emerging or re-emerging pathogens continue to pose significant challenges to global public health. In response, the scientific community has been urged to create advanced platform technologies to meet the ever-increasing needs presented by these devastating diseases with pandemic potential. This review aims to bring new insights to allow for the application of advanced nanomaterials in future diagnostics, vaccines, and antiviral therapies, thereby addressing the challenges associated with the current preparedness strategies in clinical settings against viruses. The application of nanomaterials has advanced medicine and provided cutting-edge solutions for unmet needs. Herein, an overview of the currently available nanotechnologies is presented, highlighting the significant features that enable them to control infectious diseases, and identifying the challenges that remain to be addressed for the commercial production of nano-based products is presented. Finally, to conclude, the development of a nanomaterial-based system using a "One Health" approach is suggested. This strategy would require a transdisciplinary collaboration and communication between all stakeholders throughout the entire process spanning across research and development, as well as the preclinical, clinical, and manufacturing phases.

Application of Nanomaterials as an Advanced Strategy for the Diagnosis, Prevention, and Treatment of Viral Diseases

The coronavirus disease (COVID-19) pandemic poses serious global health concerns with the continued emergence of new variants. The periodic outbreak of novel emerging and re-emerging infectious pathogens has elevated concerns and challenges for the future. To develop mitigation strategies against infectious diseases, nano-based approaches are being increasingly applied in diagnostic systems, prophylactic vaccines, and therapeutics. This review presents the properties of various nanoplatforms and discusses their role in the development of sensors, vectors, delivery agents, intrinsic immunostimulants, and viral inhibitors. Advanced nanomedical applications for infectious diseases have been highlighted. Moreover, physicochemical properties that confer physiological advantages and contribute to the control and inhibition of infectious diseases have been discussed. Safety concerns limit the commercial production and clinical use of these technologies in humans; however, overcoming these limitations may enable the use of nanomaterials to resolve current infection control issues via application of nanomaterials as a platform for the diagnosis, prevention, and treatment of viral diseases.

Hesperidin and Chlorogenic Acid Synergistically Inhibit the Growth of Breast Cancer Cells via Estrogen Receptor/Mitochondrial Pathway

Breast cancer is the most common cancer in women worldwide. Hesperidin (Hes) and chlorogenic acid (CA) are traditional medicinal molecules that abundantly exist in natural plants or foods. These compounds have been shown to prevent and suppress various cancers and therefore can be utilized as adjunctive therapies to aid cancer treatment. Here, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays show a greater synergistic inhibitory effect on the growth of breast cancer cells, MCF-7, but not normal breast cells, MCF-10A, than hesperidin or chlorogenic acid alone. We present the possible molecular signaling pathways in MCF-7 cells with or without herbal molecule treatments via proteomic approaches. The data were further analyzed by Ingenuity Pathway Analysis (IPA) and confirmed by quantifying mRNA associated with the estrogen-receptor signaling pathway and mitochondrial functions. We demonstrated that the expression of CYC1, TFAM, ATP5PB, mtATP6, mtDNA, and NRF-1 were decreased upon 12 h treatment, and subsequent ATP production was also significantly decreased at 24 h. These results identified a synergistic effect induced by combinational treatment with hesperidin and chlorogenic acid, which can regulate mitochondria and ATP production through the estrogen receptor pathway in MCF-7 cells. However, none of the treatments induced the generation of reactive oxygen species (ROS), suggesting that ROS likely plays no role in the observed pharmacological activities. Overall, our study sheds light on the adequacy of hesperidin and chlorogenic acid to serve as an adjunctive therapy when co-administrated with chemotherapy drugs in breast cancer patients.

Nanoscience and quantum science-led biocidal and antiviral strategies

The severe acute respiratory syndrome coronavirus (SARS-CoV-2) caused the COVID-19 pandemic. According to the World Health Organization, this pandemic continues to be a serious threat to public health due to the worldwide spread of variants and their higher rate of transmissibility. A range of measures are necessary to slow the pandemic and save lives, which include constant evaluation and the careful adjustment of public-health responses augmented by medical treatments, vaccines and protective gear. It is hypothesized that nanostructured particulates underpinned by nanoscience and quantum science yield high-performing antiviral strategies, which can be applied in preventive, diagnostic, and therapeutic applications such as face masks, respirators, COVID test kits, vaccines, and drugs. This review is aimed at providing comprehensive and cohesive perspectives on various nanostructures that are suited to intensifying and amplifying the effectiveness of antiviral strategies. Growing scientific literature over the past eighteen months indicates that quantum dots, iron oxide, silicon oxide, polymeric and metallic nanoparticles have been employed in COVID-19 diagnostic assays, vaccines, and personal protective equipment (PPE). Quantum dots have displayed their suitability as more sensitive imaging probes in diagnostics and prognostics, and as controlled drug-release carriers that target the virus. Nanoscience and quantum science have assisted the design of advanced vaccine delivery since nanostructured materials are suited for antigen delivery, as mimics of viral structures and as adjuvants. Furthermore, the quantum science- and nanoscience-supported tailored functionalization of nanostructured materials offers insight and pathways to deal with future pandemics. This review seeks to illustrate several examples, and to explain the underpinning quantum science and nanoscience phenomena, which include wave functions, electrostatic interactions, van der Waals forces, thermal and electrodynamic fluctuations, dispersion forces, local field-enhancement effects, and the generation of reactive oxygen species (ROS). This review discusses how nanostructured materials are helpful in the detection, prevention, and treatment of the SARS-CoV-2 infection, other known viral infection diseases, and future pandemics.

Precursor-dependent structural diversity in luminescent carbonized polymer dots (CPDs): the nomenclature

Carbon dots (CDs) have received immense attention in the last decade because they are easy-to-prepare, nontoxic, and tailorable carbon-based fluorescent nanomaterials. CDs can be categorized into three subgroups based on their morphology and chemical structure: graphene quantum dots (GQDs), carbon quantum dots (CQDs), and carbonized polymer dots (CPDs). The detailed structures of the materials can vary significantly, even within the same category. This property is particularly predominant in chemically synthesized CPDs, as their formation proceeds via the polymerization-carbonization of molecules or polymer precursors. Abundant precursors endow CPDs with versatile structures and properties. A wide variety of carbon nanomaterials can be grouped under the category of CPDs because of their observed diversity. It is important to understand the precursor-dependent structural diversity observed in CPDs. Appropriate nomenclature for all classes and types of CPDs is proposed for the better utilization of these emerging materials.

Antimicrobial Activity of Curcumin in Nanoformulations: A Comprehensive Review

Curcumin (CUR) is a natural substance extracted from turmeric that has antimicrobial properties. Due to its ability to absorb light in the blue spectrum, CUR is also used as a photosensitizer (PS) in antimicrobial Photodynamic Therapy (aPDT). However, CUR is hydrophobic, unstable in solutions, and has low bioavailability, which hinders its clinical use. To circumvent these drawbacks, drug delivery systems (DDSs) have been used. In this review, we summarize the DDSs used to carry CUR and their antimicrobial effect against viruses, bacteria, and fungi, including drug-resistant strains and emergent pathogens such as SARS-CoV-2. The reviewed DDSs include colloidal (micelles, liposomes, nanoemulsions, cyclodextrins, chitosan, and other polymeric nanoparticles), metallic, and mesoporous particles, as well as graphene, quantum dots, and hybrid nanosystems such as films and hydrogels. Free (non-encapsulated) CUR and CUR loaded in DDSs have a broad-spectrum antimicrobial action when used alone or as a PS in aPDT. They also show low cytotoxicity, in vivo biocompatibility, and improved wound healing. Although there are several in vitro and some in vivo investigations describing the nanotechnological aspects and the potential antimicrobial application of CUR-loaded DDSs, clinical trials are not reported and further studies should translate this evidence to the clinical scenarios of infections.