Nanoparticles in Modern Antimicrobial and Antiviral Applications

Nanoparticles have been used as antimicrobial and antiviral materials, especially, in advanced healthcare applications. This is due to their advanced physicochemical and biomedical (size and solubility) properties. Silver (Ag) is the first material used for several medical applications in human daily life. Mainly, Ag nanoparticles can generate influential active radicals, that can easily interact with bacterial envelopes and inhibit bacterial growth. In addition, they can be used against many viruses (including COVID-19) and also for the control of the virus spread and viral infections. This chapter addresses the importance of Ag and its derivative materials against several bacteria and viruses. In addition, we highlight, briefly, the reports on the recent articles.

Gold nanoparticles (AuNPs) address several biomedical issues and they have garnered significant attention as incredibly promising materials. In recent years, many emerging infectious diseases caused by multi-resistant bacteria or viruses have given rise to some life-threatening disorders. In order to create novel medicines for the treatment of diseases and the emergence of multidrug-resistant strains, creative approaches are now necessary due to the dearth of new antibiotics. In this context, AuNPs have become a subject of interest for many research groups because of their good stability and excellent biocompatibility. According to various studies, AuNPs and gold-based compounds are very effective at killing bacteria and viruses by disrupting the cell membrane and inducing oxidative stress, apoptosis, and synergy. As an excellent drug carrier and large surface area, the antibacterial characteristics of AuNPs can be improved by altering their structure and size, or including other substances. After being modified and coupled with existing antibacterial medications, the AuNPs can play better antibacterial or antiviral activities against some novel diseases. This review focuses on AuNPs’ biological activities and their potential future biomedical applications as antiviral and antibacterial nanotheranostic agents.

Transition metals, e.g., platinum (Pt), possess unique physicochemical and biological characteristics due to the presence of half-filled d-orbitals, with which they can exhibit variable oxidation states and catalytic ability and they can form complex and colored compounds. Besides, they display exceptional surficial properties that play a vital role in automobile catalytic converters and petrochemical cracking applications. However, catalysis is versatile and pivotal among the others that attracted attention owing to its diversity, which is further categorized as homogeneous, heterogeneous, and biocatalysts in terms of their functionality. Owing to their distinctive hard complex, heavy, and less-reactive nature, Pt nanoparticles (NPs) are very good catalytic materials and their compounds attracted considerable interest in the biomedical field of applications, such as nanomedicine, photothermal therapy, radiation dose enhancement, computed tomography (CT), and X-ray. Furthermore, Pt-based materials possess excellent antioxidant, antibacterial, antiviral, and anticancer nature, enabling them as nanocarriers, nanozymes, and nanosensors for diagnostic purposes. Cancer is one of the most intensely researched fields, where Pt derivatives, such as cisplatin, carboplatin, and oxaliplatin, are widely utilized in clinical research to combat various drug-resistant bacteria and to lessen the undesirable side effects of radiation and chemotherapy. Pt-based compounds have great potential and their drugs are being examined extensively ever since their anticancer activity was discovered. They have unexplored potential for the fabrication of drugs that are useful for viral infections. As a result, several novel Pt compounds were produced, some of which have intriguing antiviral characteristics. This chapter aims to demonstrate the potential use of Pt NPs in antibacterial and antiviral applications.

SiO₂ nanoparticles have emerged as a potential solution for combating bacterial and viral infections due to their unique physicochemical properties. These nanoparticles possess a high surface area-to-volume ratio, allowing them to adsorb onto the surface of bacterial and viral cells and disrupt their membrane integrity. Additionally, SiO₂ nanoparticles can generate reactive oxygen species (ROS) upon exposure to light or heat, which can induce oxidative stress and damage to bacterial and viral cells. However, the use of SiO₂ nanoparticles as antimicrobial agents also presents certain challenges and risks, such as their potential toxicity to human cells and the environment. In this chapter, we review the latest research work, highlighting the advantages and disadvantages of SiO₂ nanoparticles and their potential applications for COVID-19 prevention, detection, and treatment. We also examine the toxicity concerns associated with SiO₂ nanoparticles and the need for further research to ensure their safe use. Overall, this chapter aims to provide a comprehensive overview of the current state-of-the-art in SiO₂ nanoparticle research for antimicrobial applications, with a focus on COVID-19 prevention and treatment.

Nanoparticles (NPs) exhibit superior antimicrobial activity because of their distinct structural morphology (particle size and shape). However, the antimicrobial performance of most NPs is associated with several shortcomings, which limit their practical applications. Various synthetic approaches have been employed to evaluate the correlation between controlled particle size and antimicrobial properties of NPs. This chapter focuses on the utilization of CuO nanoparticles in antimicrobial and antiviral applications. It explores the various synthesis methods for producing CuO nanoparticles. The chapter also discusses the toxicity of CuO nanoparticles toward normal and other cells, considering factors, such as: size, shape, and concentration. Furthermore, the chapter delves into the mechanism of action of CuO nanoparticles, which involves the generation of reactive oxygen species (ROS), upon interaction with microorganisms. It covers the characterization techniques employed to study the properties of CuO nanoparticles. The chapter reviews the recent literature on the application of CuO nanoparticles in antimicrobial and antiviral fields (COVID-19). It highlights their effectiveness in inhibiting the growth of bacteria, fungi, and viruses. Finally, the chapter will highlight the challenges and future directions in the field of CuO nanoparticles for antimicrobial and antiviral applications.

Zinc oxide (ZnO) nanoparticles are promising nanotherapeutics used in several biomedical applications. Some of the unique features of ZnO nanoparticles are good optical, piezoelectric, and semiconducting properties together with good biodegradability and low toxicity. The zinc ion is also an important trace element crucial for adults for metabolism. ZnO nanoparticles are known to exhibit excellent anticancer, antibacterial, antiviral, and antifungal activities. The aforementioned biological activities are attributed to their capability to induce apoptosis and generate reactive oxygen species. ZnO nanoparticles have also been explored as drug nanocarriers and bioactive agents for targeted drug delivery with reduced side effects and synergistic effects. Some available data have shown the risk associated with the uncontrollable use of nanoformulations of zinc. The increasing use of ZnO nanoparticles offers great benefits biomedically, but its toxic effects over a prolonged period need to be studied. The design of ZnO nanoparticles for biomedical applications has a promising capability to flourish with the potential of clinical translation. This chapter reports a summary of the recent advances in the synthesis of ZnO nanoparticles and platforms loaded with ZnO nanoparticles with antimicrobial activities—antibacterial, antifungal, antiviral, and antiparasitic, and toxicity effects.

Titanium dioxide, which is nontoxic and abundant in nature, has excellent optical and physicochemical properties. Hence, titanium dioxide nanoparticles (TiO₂NPs) are generally applied as photocatalysts because of their non-toxicity, chemical stability, resistance to corrosion, and low-cost requirement for production. However, recent studies on the biogenic synthesis of TiO₂NPs reported its potential antimicrobial activities. Thus, this chapter explains the application of TiO₂NPs to inhibit various bacterial and fungal pathogens. Certain bacteria such as Acinetobacter baumannii S1, Acinetobacter seohaensis N3, Aeromonas hydrophila, Bacillus cereus A1, Bacillus mycoides, Rummeliibacillus pycnus M1, and Streptomyces sp. HC1 are reported to synthesize mostly spherical TiO₂NPs that can vary from 20 to 80 nm in size. Likewise, fungi such as Aspergillus flavus, Fomes fomentarius, Fomitopsis pinicola, and Trichoderma citrinoviride can also synthesize therapeutically active TiO₂NPs. Medicinal plants have rich phytochemistry that has been exploited for the synthesis of TiO₂NPs. Certain plants such as Azadirachta indica, Ledebouria revoluta, Luffa acutangula, Mentha arvensis, Ocimum americanum, Piper betel, Prunus yedoensis, and Trigonella foenum-graecum can also synthesize TiO₂NPs where extracts of different plant parts are used. The biogenic TiO₂NPs are reported to inhibit pathogenic bacteria such as Bacillus cereus, Clostridium perfringens, Clostridium tetani, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella paratyphi, Salmonella typhi, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Vibrio cholerae, and Yersinia enterocolitica. Similarly, biologically fabricated TiO₂NPs can effectively inhibit pathogenic fungi such as Aspergillus niger and Candida albicans. Hence, a further in-depth understanding of the mechanism of action of TiO₂NPs against all these bacterial and fungal pathogens can help to develop broad-spectrum novel nanomedicine in future. Furthermore, there is a great scope in future for exploring the antiviral properties of the biogenic TiO₂NPs.

Cerium oxide nanoparticles (CeO₂ NPs) have garnered significant attention in the realm of biomedical applications due to their unique properties and versatile potential. The chapter provides a comprehensive overview of the multifaceted landscape surrounding the utilization of CeO₂ NPs in biomedicine and highlighting their remarkable catalytic and redox properties. These attributes have positioned them as promising candidates for diverse biomedical roles. The advantages and disadvantages section explores the dual nature of CeO₂ NPs. Their antioxidative behavior, stemming from their ability to switch between Ce³⁺ and Ce⁴⁺ oxidation states, is a notable advantage, making them potential candidates for therapeutic interventions in oxidative stress-related diseases. However, their redox capability also raises concerns regarding potential pro-oxidant effects, emphasizing the need for meticulous evaluation. The toxicity aspect underscores the importance of understanding the potential risks associated with CeO₂ NPs utilization. Addressing their interactions with biological systems, including cells and tissues, is imperative. While CeO₂ NPs’ antioxidant properties are promising, there are also concerns regarding their potential to induce oxidative stress and inflammation. The antimicrobial application section highlights the emerging role of CeO₂ NPs in combating microbial infections. Their ability to mitigate bacterial growth, biofilm formation, and even antibiotic-resistant strains underscores their potential to revolutionize infection control strategies. The role of CeO₂ NPs in the context of the COVID-19 pandemic with recent research has explored their potential in antiviral applications, including as inhibitors of viral enzymes and agents for sanitizing surfaces. Their contribution to mitigating the impact of COVID-19 underscores their relevance in contemporary healthcare challenges. This chapter culminates with an exploration of recent advancements in CeO₂ NPs research. As a dynamic field, ongoing studies are unraveling novel aspects of their behavior, interactions, and applications. These insights pave the way for innovative therapeutic strategies and personalized medical interventions. In summary, this chapter provides an encompassing glimpse into the multifaceted world of CeO₂ NPs for biomedical applications. Their advantages, disadvantages, toxicity considerations, antimicrobial potential, and recent contributions in battling COVID-19 collectively underscore their significance in shaping the future of healthcare and medicine.

Metal oxide nanoparticles, such as MgO nanoparticles (NPs), possess various beneficial properties like antibacterial, antiviral, antifungal, and antibiofilm effects. However, traditional chemical synthesis methods for producing MgO NPs have two issues: poor biocompatibility and the formation of harmful substances that can harm the environment. To address these concerns, there has been a growing interest in eco-friendly techniques, employing greener chemistry to produce nanoparticles through alternative routes. Four distinct approaches are used by plants, fungi, bacteria, and algae to generate MgO nanoparticles. These methods utilize the metabolites produced by biological materials and their extracts to stabilize and cap the particles, leading to nanoparticle formation. Factors like pH, extraction ratio, and temperature significantly impact the size, stability, shape, and surface area of the resulting MgO nanoparticles. The use of green methods or biomethods to synthesize nanoparticles offers several advantages, such as being eco-friendly and nontoxic to living organisms, making them well-suited for various biological applications. The synthesized MgO nanoparticles have demonstrated promising potential as effective agents against pathogens, particularly in biomedical fields, due to their biocompatibility and eco-friendliness. Their antibacterial properties primarily result from the disruption of cell walls or membranes and the generation of reactive oxygen species (ROS). However, there remain gaps in our understanding of the long-term toxicity, diffusion, absorption, and excretion mechanisms of these nanoparticles. To further explore their potential uses, additional research is required, either in laboratory settings (in vitro) or within living organisms (in vivo). By genetically modifying plant sources, it becomes feasible to control the configuration, uniformity, and resilience of the nanoparticles. Conducting thorough assessments of the antioxidant potential of biogenic MgO NPs will provide valuable insights into their practical applications. In conclusion, eco-friendly synthesis methods for MgO nanoparticles hold great promise for industrial and biological uses. Their inherent biocompatibility and environmentally friendly nature make them valuable candidates for a wide range of applications, especially in combating pathogens. However, further research is necessary to fully realize their potential benefits and explore their contributions to societal betterment.

Multidrug-resistant (MDR) bacteria (gram-positive and gram-negative) and viruses (COVID-19) have contributed to an increase in health-related issues worldwide. Clinical complications caused by MDR strains are rapidly deteriorating. Simultaneously, cancers are the primary reason for mortality and morbidity worldwide, behind cardiovascular disease. Chemotherapy is a common treatment for cancer. However, it has serious health consequences, such as suppression of bone marrow, hair loss, and gastrointestinal issues, because it eliminates all rapidly dividing cells, including normal and tumor cells. As nanoscience and technology have expanded the opportunities to investigate antibacterial, antiviral, and anticancer nanomaterials, they are becoming increasingly highly significant as drug alternatives for the treatment of antibacterial, antiviral, and anticancer activities. Biocidal activity and biocompatibility of nanomaterials (NMs) are critical for healthcare applications.

NMs can overcome the blood-brain barrier, reach the pulmonary system, and adsorb through endothelial cells as they have enhanced colloidal stability and increased bioavailability. It may be intensely dependent on the production of reactive oxygen species (ROS) in NMs, due to their size, large surface areas, oxygen vacancies, ion release, and diffusion ability. The photocatalytic effects of metal oxide nanomaterials are promising for microbial, viral, and cancer cell inactivation. However, antibacterial, antiviral, and anticancer activities are strongly related to the generation of ROS in nanomaterials. On the other hand, the surfaces of metal oxide NMs, in contact with light, cause oxidative stress in cells, eventually leading to the death of bacterial, viral, and cancer cells. Tin oxide (SnO₂) NMs are a potential contender for catalysis, medicine, pollution management, and energy storage due to their large band gap (3.6–3.8 eV), good thermal and chemical stability, and excellent transparency. Electron-hole pairs are formed when a metal oxide photocatalyst is exposed to light with an energy higher than its band gap. SnO₂ NMs have a large surface area and can be an ideal photocatalyst. The SnO₂ NMs have a positive charge, and the microbial cell surface has a negative charge due to electrostatic interaction between microbes and nanomaterials. It was used to bind and trap microbes before they could enter the host cell. They cling to the microbe particle limit for microbial entrance, replication, and cell-to-cell fusion. This chapter is focused on investigating SnO₂ NMs and to emphasize their medical applications, particularly antibacterial, antiviral, and anticancer therapies.

The use of nanotechnology in medical applications is increasing day by day. Thanks to their unique physical, chemical, mechanical, electronic, and magnetic properties, nanoparticles are successfully used in the diagnosis, treatment, and prevention of many diseases. Today, metallic nanoparticles constitute one of the most important instruments of nanotechnological approaches. It has been proven by previous studies that metallic nanoparticles show extremely strong antibacterial, antiviral, and anticancer activity. It is known that the presence of microorganisms and cancer cells that are resistant to current conventional drug applications is one of the biggest obstacles in preventing the spread of diseases in large geographies and their development in the human body. For this reason, there is a great need to develop new-generation treatment applications. The fact that metallic nanoparticles are effective on drug-resistant microorganisms and show a much higher inhibitory activity than current treatment applications has increased the importance of these agents in the field of medicine. However, the biggest obstacle to the application of metallic nanoparticles on living things is the toxicity of these agents. Today, various methods are being developed to reduce the toxicity of metallic nanoparticles and to apply them to humans. The biological production of nanoparticles by green synthesis method instead of chemical synthesis is the most important of these advanced methods. Within the scope of this review, different production methods of nickel oxide (NiO) nanoparticles, the importance of which has been increasing in recent years, and the factors that change the efficiency of the produced nanoparticles in biological applications are discussed, and recent studies on antimicrobial applications of NiO nanoparticles have been brought together.

Aluminum oxide nanoparticles (Al₂O₃ NPs) have attracted significant attention to various scientific and industrial fields due to their unique bio−/physicochemical properties: high surface area, high hardness, thermal stability, biocompatibility, surface functionalization, and electrical insulation. This chapter exposes the key aspects of Al₂O₃ NPs synthesis that include sol-gel, hydrothermal, combustion, and green methods. Each method provides control over the particle size, shape, and chemical surface, enabling tailored nanoparticles for specific applications. In catalysis, Al₂O₃ NPs serve as efficient catalyst supports, enhancing reaction rates and selectivity. Additionally, their remarkable dielectric properties make them valuable for electronic and optoelectronic devices. Moreover, Al₂O₃ NPs have demonstrated promising results in biomedical applications, including drug delivery systems, biomedical imaging, biosensing, and tissue engineering. Furthermore, recent studies have shown that Al₂O₃ NPs have potent antimicrobial and antiviral properties. Due to their small size, they can penetrate bacterial and viral cells more effectively, increasing the efficacy of their action. Al₂O₃ NPs can be incorporated into coatings for medical devices and hospital surfaces, helping prevent bacterial adhesion and biofilm formation, thereby reducing the risk of infections. In addition, Al₂O₃ NPs have demonstrated potent adjuvant activity for several vaccines throughout history, targeting and neutralizing a wide range of microorganisms. In the future, Al₂O₃ NPs hold great promise as key components in a wide range of advanced materials and applications, like advanced coatings, energy storage systems, catalysis, biomedical applications, environmental remediation, optoelectronics, photonics, and personal care products.

Iron oxide nanoparticles are the most studied material approved by the Food and Drug Administration. At specific diameters (from 15 nm and no more than 100 nm), magnetic iron oxide, which is made up of magnetite, is used as drug delivery vehicles and for thermal-based therapeutics. This material can be efficiently used in biomedical applications such as diagnostics, imaging, and photothermal therapies. Properties such as biocompatibility and stability of nanoparticles fill the niche of applications that require properties unattainable by organic materials. The application of superparamagnetic iron oxide nanoparticles (SPIONs) acts as an advanced platform for antimicrobial, drug delivery, contrast agent in image diagnostics and hyperthermia treatment for cancer applications. Iron oxide nanoparticles are attributed to their exceptional properties, such as size, shape, magnetism, and biocompatibility. Iron oxide nanoparticles hold potent antibacterial activity against various gram-positive and gram-negative bacteria. In this chapter, iron oxide nanoparticles are exploited in different model organisms ranging from prokaryotes to eukaryotes, elucidating their cellular functions relative to their antibacterial activity, drug delivery, and toxicity. Current knowledge reveals that the comprehensive research can provide significant study parameters and recent developments in the nanomedicine field. Magnetic nanoparticles for biological applications are seeing a significant increase in research and development in recent years.

The rise of antibiotic-resistant bacteria is a major concern for public health. To address this issue, there is a need to develop innovative antimicrobial materials. MXene-based nanomaterials have emerged as promising candidates for healthcare applications. These materials are two-dimensional transition metal carbides, nitrides, or carbonitrides with unique properties, such as high electrical conductivity, mechanical strength, and large surface area. By incorporating MXenes into nanocomposites, their antimicrobial properties can be enhanced. Through various synthesis approaches and microstructure examination, researchers have gained fundamental insights into the properties of these materials. MXenes possess abundant active sites that allow for diverse modifications. For instance, constructing heterojunctions has proven effective in delaying the recombination of electrons and holes, thereby enhancing the generation of ROS. Numerous innovative and intricate designs have been developed in the context of antimicrobial applications and related fields, highlighting the potential of MXenes in a post-antibiotic era. The alarming spread of harmful bacterial growth and the emergence of highly resistant bacteria have posed significant public health risks, prompting researchers to devise strategies that do not rely on antibiotics to combat these microorganisms. This chapter provides an overview of the synthesis and antimicrobial performance of MXene-based nanocomposites. The antimicrobial performance of MXene-based nanocomposites against a wide range of bacteria is evaluated. Additionally, the potential applications of MXene-based nanocomposites in various fields and the potential applications of MXene-based materials in fighting COVID-19 are discussed.

Over the past 10 years, significant advancements have been made in exploring the potential uses of materials based on MXenes in areas related to antibacterial properties. Through various approaches to synthesis and the examination of microstructures, fundamental insights into the properties of these captivating materials have been obtained. The abundant active sites present in MXenes allow for diverse modifications. For example, the construction of heterojunctions has proven effective in delaying the recombination of electrons and holes, thus enhancing the generation of reactive oxygen species. So far, numerous innovative and intricate designs have been applied in the context of antibacterial applications and related fields, underscoring the promising potential of MXenes in a post-antibiotic era. The alarming spread of harmful bacterial growth and the emergence of highly resistant bacteria have posed significant public health risks, prompting researchers to devise strategies devoid of antibiotics to combat these formidable microorganisms.

Microbial infections, such as multidrug-resistant infections that represent a serious risk to public health, have drastically increased on a global scale. Therefore, the development of novel antimicrobial agents is urgently needed for the treatment of these infections. Nowadays, nanotechnology offers advances in science across a wide range of industries, including medicine, genetics, and infectious diseases. The interaction of nanomaterials with microorganisms is quickly transforming the field of bioengineering by providing benefits for both therapeutic and diagnostic uses. Different organic and inorganic nanoparticles have special physical characteristics that are advantageous for the development of various antiviral and antibacterial agents. Especially, organic nanomaterials have a greater advantage over others due to their biodegradability and biocompatibility. Carbon nanomaterials, such as graphene/graphene oxide, fullerenes, carbon nanotubes, and their nanocomposites, have antibacterial properties. However, their antibacterial properties depend on their structure, functional groups, and some other factors. Considering their potent antiviral and antibacterial properties, functionalized carbon nanotubes show considerable potential in the combat against microbial infections. Carbon nanotubes can play a significant role in the deactivation of microorganisms because of their small size and the ability to pierce bacterial cell walls. They can be single-walled and multi-walled, depending on their number of carbon layers. On the other hand, functionalized carbon nanotubes showed better antimicrobial properties. The recent developments in the antimicrobial and antiviral effects of carbon nanotubes and their nanocomposites are examined in the present chapter. Thereby, in order to shed light on the potential of these nanostructures, we summarize the most significant immunological aspects of diverse viral and microbial infections and discuss key developments and difficulties while using carbon nanotubes for prevention, diagnosis, and treatment of these infections.

Despite the rapid development of science and technology, infection threatens human’s life. Infections are caused by the growing global population and increasing contamination of water and air. Antibiotics are generally prescribed to treat microbial infections. However, many microorganisms have mutated and developed resistance against antibiotics. Nanomaterials have been presently studied to use as an alternative to antibiotics, due to their advantageous properties and unique mechanisms of action towards microbes. Among various nanomaterials, carbon dots have attracted huge interest due to their unique physical, chemical, electrical, and biological properties. This book chapter explicitly targets the applications of carbon dots as antimicrobial agents and their toxicity effects in humans. In this chapter, various synthesis methods to control the physiochemical properties of carbon dots have been discussed. In addition, the antimicrobial and antiviral properties of carbon dots have been discussed. Notably, their mechanism of actions against various microbes has been discussed in detail. I believe this chapter will provide insights to readers on developing carbon dots for various biomedical applications.

Graphene oxide (GO) is a nanomaterial with immense potential in the field of antibacterial and antiviral applications. This chapter discusses toxicity concerns, advantages, and disadvantages of GO, as well as its applications as biosensors and its effectiveness against bacteria, viruses (including COVID-19), and recent research developments. The chapter concludes by emphasizing the need for further research to fully understand the capabilities and limitations of GO in biomedical applications.