Marine microorganisms for synthesis of metallic nanoparticles and their biomedical applications

Biosynthesis of Zinc Nanoparticles From Actinobacterium Streptomyces Species and Their Biological Potential

BACKGROUND

In today's world, antibiotic-resistant microorganisms are a major concern. There is solid evidence that metal nanoparticles (NPs) tend to have antimicrobial properties. The most effective substitute for antibiotic resistance is the incorporation of metal NPs. The antibacterial properties of NPs are currently being explored and shown to be successful. Zinc (Zn) NPs that are biosynthesized from marine Actinobacterium proved to be more biocompatible, bioactive, and affordable.  Aim: This study aims to investigate the synthesis of ZnNPs from Actinobacterium Streptomyces species and their antimicrobial effects against gram-positive and gram-negative bacteria.

MATERIALS AND METHODS

The current study uses natural, considerably safer processes to synthesize ZnNPs from marine Actinobacteria with little to no negative side effects. It involves sample collection, identification, and isolation of Actinobacterium Streptomyces species. The isolated sample was air-dried, and extracts of ZnNPs were taken. Among the isolates from marine sediment, two Actinobacteria that generate bioactive secondary metabolites-Streptomyces species (MOSEL-ME28) and Rhodococcus rhodochrous (MOSEL-ME29)-were selected for extracellular synthesis of ZnNPs. The antimicrobial activity of the biosynthesized ZnNPs from marine Actinobacteria was analyzed against Staphylococcus (MRSA), Klebsiella pneumoniae, and Streptococcus mutans. The results were statistically analyzed and graphs were created.

RESULTS

ZnNPs obtained from Actinobacterium Streptomyces species exhibited antimicrobial effects against Staphylococcus (MRSA), Klebsiella, and Streptococcus mutans. At 280 nm wavelength, analysis of the UV spectrum showed a notable absorbance value of 1.8. The antibacterial efficacy against Staphylococcus MRSA, Klebsiella species, and Streptococcus mutans was assessed by measuring the zone of inhibition in diameter. The zones of inhibition were 8, 8, and 7 mm on the evaluation for Streptococcus mutans, S. aureus, and Klebsiella species, respectively, at a dose of 75 μg/mL. When the dosage was increased to 100 μg/mL, the inhibition zones were found to be 9.5, 9, and 7.5 mm for the respective bacterial strains.

CONCLUSION

ZnNPs are biosynthesized from marine Actinobacterium Streptomyces species in this research study. They have a significant antimicrobial activity against both gram-positive and negative bacteria. This indicates that ZnNPs have enormous antimicrobial potential and have an extensive spectrum of applications. However, clinical trials must be completed before it can be used safely on patients.

A review of physical, chemical and biological synthesis methods of bimetallic nanoparticles and applications in sensing, water treatment, biomedicine, catalysis and hydrogen storage

This article provides an in-depth analysis of various fabrication methods of bimetallic nanoparticles (BNP), including chemical, biological, and physical techniques. The review explores BNP's diverse uses, from well-known applications such as sensing water treatment and biomedical uses to less-studied areas like breath sensing for diabetes monitoring and hydrogen storage. It cites results from over 1000 researchers worldwide and >300 peer-reviewed articles. Additionally, the article discusses current trends, actionable recommendations, and the importance of synthetic analysis for industry players looking to optimize manufacturing techniques for specific applications. The article also evaluates the pros and cons of various fabrication methods, highlighting the potential of plant extract synthesis for mass production of capped BNPs. However, it warns that this method may not be suitable for certain applications requiring ligand-free surfaces. In contrast, physical methods like laser ablation offer better control and reactivity, especially for applications where ligand-free surfaces are critical. The report underscores the environmental benefits of plant extract synthesis compared to chemical methods that use hazardous chemicals and pose risks to extraction, production, and disposal. The article emphasizes the need for life cycle assessment (LCA) articles in the literature, given the growing volume of research on nanotechnology materials. This article caters to researchers at all stages and applies to various fields applying nanomaterials.

A potential paradigm in CRISPR/Cas systems delivery: at the crossroad of microalgal gene editing and algal-mediated nanoparticles

Microalgae as the photosynthetic organisms offer enormous promise in a variety of industries, such as the generation of high-value byproducts, biofuels, pharmaceuticals, environmental remediation, and others. With the rapid advancement of gene editing technology, CRISPR/Cas system has evolved into an effective tool that revolutionised the genetic engineering of microalgae due to its robustness, high target specificity, and programmability. However, due to the lack of robust delivery system, the efficacy of gene editing is significantly impaired, limiting its application in microalgae. Nanomaterials have become a potential delivery platform for CRISPR/Cas systems due to their advantages of precise targeting, high stability, safety, and improved immune system. Notably, algal-mediated nanoparticles (AMNPs), especially the microalgae-derived nanoparticles, are appealing as a sustainable delivery platform because of their biocompatibility and low toxicity in a homologous relationship. In addition, living microalgae demonstrated effective and regulated distribution into specified areas as the biohybrid microrobots. This review extensively summarised the uses of CRISPR/Cas systems in microalgae and the recent developments of nanoparticle-based CRISPR/Cas delivery systems. A systematic description of the properties and uses of AMNPs, microalgae-derived nanoparticles, and microalgae microrobots has also been discussed. Finally, this review highlights the challenges and future research directions for the development of gene-edited microalgae.

Metallic Nanoparticles: Their Potential Role in Breast Cancer Immunotherapy via Trained Immunity Provocation

Owing to drawbacks in the current common cancer therapies including surgery, chemotherapy and radiotherapy, the development of more reliable, low toxic, cost-effective and specific approaches such as immunotherapy is crucial. Breast cancer is among the leading causes of morbidity and mortality with a developed anticancer resistance. Accordingly, we attempted to uncover the efficacy of metallic nanoparticles (MNPs)-based breast cancer immunotherapy emphasizing trained immunity provocation or innate immunity adaptation. Due to the immunosuppressive nature of the tumor microenvironment (TME) and the poor infiltration of immune cells, the potentiation of an immune response or direct combat is a goal employing NPs as a burgeoning field. During the recent decades, the adaptation of the innate immunity responses against infectious diseases and cancer has been recognized. Although the data is in a scarcity with regard to a trained immunity function in breast cancer cells' elimination, this study introduced the potential of this arm of immunity adaptation using MNPs.

A review on nanoparticles: characteristics, synthesis, applications, and challenges

The significance of nanoparticles (NPs) in technological advancements is due to their adaptable characteristics and enhanced performance over their parent material. They are frequently synthesized by reducing metal ions into uncharged nanoparticles using hazardous reducing agents. However, there have been several initiatives in recent years to create green technology that uses natural resources instead of dangerous chemicals to produce nanoparticles. In green synthesis, biological methods are used for the synthesis of NPs because biological methods are eco-friendly, clean, safe, cost-effective, uncomplicated, and highly productive. Numerous biological organisms, such as bacteria, actinomycetes, fungi, algae, yeast, and plants, are used for the green synthesis of NPs. Additionally, this paper will discuss nanoparticles, including their types, traits, synthesis methods, applications, and prospects.

A Recent Review on Cancer Nanomedicine

Cancer is one of the most prevalent diseases globally and is the second major cause of death in the United States. Despite the continuous efforts to understand tumor mechanisms and various approaches taken for treatment over decades, no significant improvements have been observed in cancer therapy. Lack of tumor specificity, dose-related toxicity, low bioavailability, and lack of stability of chemotherapeutics are major hindrances to cancer treatment. Nanomedicine has drawn the attention of many researchers due to its potential for tumor-specific delivery while minimizing unwanted side effects. The application of these nanoparticles is not limited to just therapeutic uses; some of them have shown to have extremely promising diagnostic potential. In this review, we describe and compare various types of nanoparticles and their role in advancing cancer treatment. We further highlight various nanoformulations currently approved for cancer therapy as well as under different phases of clinical trials. Finally, we discuss the prospect of nanomedicine in cancer management.

Algal Extracts for Green Synthesis of Zinc Oxide Nanoparticles: Promising Approach for Algae Bioremediation

Zinc oxide nanoparticles (ZnO-NPs) possess unique properties, making them a popular material across various industries. However, traditional methods of synthesizing ZnO-NPs are associated with environmental and health risks due to the use of harmful chemicals. As a result, the development of eco-friendly manufacturing practices, such as green-synthesis methodologies, has gained momentum. Green synthesis of ZnO-NPs using biological substrates offers several advantages over conventional approaches, such as cost-effectiveness, simplicity of scaling up, and reduced environmental impact. While both dried dead and living biomasses can be used for synthesis, the extracellular mode is more commonly employed. Although several biological substrates have been successfully utilized for the green production of ZnO-NPs, large-scale production remains challenging due to the complexity of biological extracts. In addition, ZnO-NPs have significant potential for photocatalysis and adsorption in the remediation of industrial effluents. The ease of use, efficacy, quick oxidation, cost-effectiveness, and reduced synthesis of harmful byproducts make them a promising tool in this field. This review aims to describe the different biological substrate sources and technologies used in the green synthesis of ZnO-NPs and their impact on properties. Traditional synthesis methods using harmful chemicals limit their clinical field of use. However, the emergence of algae as a promising substrate for creating safe, biocompatible, non-toxic, economic, and ecological synthesis techniques is gaining momentum. Future research is required to explore the potential of other algae species for biogenic synthesis. Moreover, this review focuses on how green synthesis of ZnO-NPs using biological substrates offers a viable alternative to traditional methods. Moreover, the use of these nanoparticles for industrial-effluent remediation is a promising field for future research.

New aspects of lipopeptide-incorporated nanoparticle synthesis and recent advancements in biomedical and environmental sciences: a review

The toxicity of metal nanoparticles has introduced promising research in the current scenario since an enormous number of people have been potentially facing this problem in the world. The extensive attention on green nanoparticle synthesis has been focussed on as a vital step in bio-nanotechnology to improve biocompatibility, biodegradability, eco-friendliness, and huge potential utilization in various environmental and clinical assessments. Inherent influence on the study of green nanoparticles plays a key role to synthesize the controlled and surface-influenced molecule by altering the physical, chemical, and biological assets with the provision of various precursors, templating/co-templating agents, and supporting solvents. However, in this article, the dominant characteristics of several kinds of lipopeptide biosurfactants are discussed to execute a critical study of factors affecting synthesis procedure and applications. The recent approaches of metal, metal oxide, and composite nanomaterial synthesis have been deliberated as well as the elucidation of the reaction mechanism. Furthermore, this approach shows remarkable boosts in the production of nanoparticles with the very less employed harsh and hazardous processes as compared to chemical or physical method-based nanoparticle synthesis. This study also shows that the advances in strain selection for green nanoparticle production could be a worthwhile and strong economical approach in futuristic medical science research.

Recent insights into metallic nanoparticles in shelf-life extension of agrifoods: Properties, green synthesis, and major applications

Nanotechnology emerged as a revolutionary technology in various fields of applied sciences, such as biomedical engineering and food technology. The pivotal roles of nanocompounds have been explored in various fields, such as food protection, preservation, and enhancement of shelf life. In this sequence, metallic nanoparticles (MNPs) are proven to be useful in developing products with antimicrobial activity and subsequently improve the shelf life of agrifoods. The major application of MNPs has been observed in the packaging industry due to the combining ability of biopolymers with MNPs. In recent years, various metal nanoparticles have been explored to formulate various active food packaging materials. However, the method of production and the need for risk evaluation are still a topic of discussion among researchers around the world. In general, MNPs are synthesized by various chemical and physical means, which may pose variable health risks. To overcome such issues, the green synthesis of MNPs using microbial and plant extracts has been proposed by various researchers. In this review, we aimed at exploring the green synthesis of MNPs, their properties and characterization, various ways of utilizing MNPs to extend their shelf life, and, most importantly, the risk associated with these along with their quality and safety considerations.

Green Chemistry Based Gold Nanoparticles Synthesis Using the Marine Bacterium Lysinibacillus odysseyi PBCW2 and Their Multitudinous Activities

Green chemistry has paved an 'avant-garde avenue' in the production and fabrication of eco-friendly stable nanoparticles employing the utilization of biological agents. In the present study we present the first report on the potential of the marine bacterium Lysinibacillus odysseyi PBCW2 for the extracellular production of gold nanoparticles (AuNPs). Utilizing a variety of methods, AuNPs in the cell-free supernatant of L. odysseyi (CFS-LBOE) were identified and their antioxidant, antibacterial, and dye-degrading properties were examined. The visual coloring of the reaction mixture to a ruby red hue showed the production of LBOE-AuNPs; validated by means of XRD, TEM, SEM, XRD, DLS, TGA, and FT-IR analysis. Additionally, the 2,2-diphenyl-1-picrylhydrazyl technique and the well diffusion assay were used to examine their dose-dependent antioxidant and antibacterial activity. These biogenic LBOE-AuNPs showed 91% dye degradation efficiency during catalytic reduction activity on BTB dye, demonstrating their versatility as options for heterogeneous catalysis.

Marine-Bioinspired Nanoparticles as Potential Drugs for Multiple Biological Roles

The increased interest in nanomedicine and its applicability for a wide range of biological functions demands the search for raw materials to create nanomaterials. Recent trends have focused on the use of green chemistry to synthesize metal and metal-oxide nanoparticles. Bioactive chemicals have been found in a variety of marine organisms, including invertebrates, marine mammals, fish, algae, plankton, fungi, and bacteria. These marine-derived active chemicals have been widely used for various biological properties. Marine-derived materials, either whole extracts or pure components, are employed in the synthesis of nanoparticles due to their ease of availability, low cost of production, biocompatibility, and low cytotoxicity toward eukaryotic cells. These marine-derived nanomaterials have been employed to treat infectious diseases caused by bacteria, fungi, and viruses as well as treat non-infectious diseases, such as tumors, cancer, inflammatory responses, and diabetes, and support wound healing. Furthermore, several polymeric materials derived from the marine, such as chitosan and alginate, are exploited as nanocarriers in drug delivery. Moreover, a variety of pure bioactive compounds have been loaded onto polymeric nanocarriers and employed to treat infectious and non-infectious diseases. The current review is focused on a thorough overview of nanoparticle synthesis and its biological applications made from their entire extracts or pure chemicals derived from marine sources.

Design of Artificial Enzymes Bearing Several Active Centers: New Trends, Opportunities and Problems

Harnessing enzymes which possess several catalytic activities is a topic where intense research has been carried out, mainly coupled with the development of cascade reactions. This review tries to cover the different possibilities to reach this goal: enzymes with promiscuous activities, fusion enzymes, enzymes + metal catalysts (including metal nanoparticles or site-directed attached organometallic catalyst), enzymes bearing non-canonical amino acids + metal catalysts, design of enzymes bearing a second biological but artificial active center (plurizymes) by coupling enzyme modelling and directed mutagenesis and plurizymes that have been site directed modified in both or in just one active center with an irreversible inhibitor attached to an organometallic catalyst. Some examples of cascade reactions catalyzed by the enzymes bearing several catalytic activities are also described. Finally, some foreseen problems of the use of these multi-activity enzymes are described (mainly related to the balance of the catalytic activities, necessary in many instances, or the different operational stabilities of the different catalytic activities). The design of new multi-activity enzymes (e.g., plurizymes or modified plurizymes) seems to be a topic with unarguable interest, as this may link biological and non-biological activities to establish new combo-catalysis routes.

Hydrogel assisted synthesis of gold nanoparticles with enhanced microbicidal and in vivo wound healing potential

The present study reports a hydrogel-based sunlight-assisted synthesis of gold nanoparticles (Au NPs) with enhanced antimicrobial and wound healing potential. The hydrogel extracted from the seeds of Cydonia oblonga was used as a reducing and capping agent to synthesize Au NPs for the first time. The as-synthesized Au NPs were characterized for an average size, shape, surface functionalization, antimicrobial, and wound healing capabilities. The cubic and rectangular-shaped Au NPs with an average edge length of 74 ± 4.57 nm depicted a characteristic surface plasmon resonance band at 560 nm. The hydrogel-based Au NPs inhibited the growth of microorganisms in zones with 12 mm diameter. In-vitro experiments showed that a minimum inhibitory concentration of Au NPs (16 µg/mL) was sufficient to mimic the 95% growth of pathogenic microorganisms in 24 h. In vivo treatment of wounds with Au NPs in murine models revealed a 99% wound closure within 5 days. Quantitative PCR analysis performed to decipher the role of Au NPs in enhanced wound healing showed an increase in the expression levels of NANOG and CD-34 proteins.

Facile green synthesis of non-genotoxic, non-hemolytic organometallic silver nanoparticles using extract of crushed, wasted, and spent Humulus lupulus (hops): Characterization, anti-bacterial, and anti-cancer studies

Since the last few decades, the green synthesis of metal nanoparticles was one of the most thrust areas due to its widespread application. The study proposed using wasted and unusable Humulus lupulus (Hops) extract to synthesize silver nanoparticles for biomedical application. The environment around us gives us many scopes to use the waste from environmental sources and turn it into something valuable. The spent Hops extract was used to synthesize silver nanoparticles (AgNP@HOPs), and the synthesized product exhibited an excellent therapeutic effect in terms of anti-bacterial and anti-cancer agents. The synthesis was optimized considering different factors like time and the concentration of AgNO₃. The silver nanoparticles were characterized in detail using different characterization techniques XRD, DLS, TEM, BET, XPS, Raman Spectroscopy, SEM, EDAX, AFM, which revealed the uniqueness of the silver nanoparticles. The average hydrodynamic size was found to be 92.42 ± 2.41 with a low polydispersity index. The presence of Ag-C and Ag-O bonds in the AgNP@HOPs indicated that it is composed of organo-silver and silver oxides. The nanoparticles were found to be spherical with an average size of 17.40 nm. The AgNPs were lethal to both E. coli and S. aureus with a MIC-50 of 201.881 μg/mL and 213.189 μg/mL, respectively. The AgNP@HOPs also exhibited an anti-cancer effect with an IC-50 of 147.175. The AgNP@HOPs exhibited less cytotoxicity and genotoxicity against normal cells and exhibited superior haemocompatibility (major criteria for drug selection). There are indeed various reports on the synthesis of silver nanoparticles, but this study proposes a green method for producing non-genotoxic, non-hemolytic organometallic silver nanoparticles using waste material with considerable therapeutic index from the environmental source with potential application in the medical industry. This work could be taken forward for in-vivo studies and for pre clinical studies.

Enhanced Anticancer Activity of Nedaplatin Loaded onto Copper Nanoparticles Synthesized Using Red Algae

Marine algae are a rich source of biologically active compounds that can be utilized in various food and pharmaceutical applications. In this study, ultrasound-assisted extraction (UAE) was optimized to maximize yield and total carbohydrate content extracted from the red algae, Pterocladia capillacea. The extract was shown to possess potent antioxidant activity of up to ~70%, and was successfully used as a reducing and capping agent in the green synthesis of copper nanoparticles, which were characterized by UV-spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS). Primarily, CuO nanoparticles with an average size of 62 nm were produced. FTIR spectra for the extract and algal-mediated CuO nanoparticles showed characteristic polysaccharide peaks. The synthesized CuO nanoparticles were subsequently loaded with nedaplatin where UV data suggested a complex formation. Nedaplatin release profiles showed a sustained release that reached a maximum at 120 h. The formulation was shown to have greater cytotoxicity relative to nedaplatin on hepatocellular carcinoma, breast cancer and ovarian cancer cell lines with IC₅₀ values of 0.40 ± 0.08, 1.50 ± 0.12, and 0.70 ± 0.09 µg/mL, respectively. Loading nedaplatin onto CuO nanoparticles synthesized using red algae extract, greatly enhances its anticancer effect.

Aggregatimonas sangjinii gen. nov., sp. nov., a novel silver nanoparticle synthesizing bacterium belonging to the family Flavobacteriaceae

Microbially synthesized nanoparticles has received increasing attentions owing to the broad applications in biology and medicine. In this study, we report a novel bacterium that biologically generates silver nanoparticles (AgNPs). This bacterium, designated strain F202Z8^T, was isolated from a rusty iron plate found in the intertidal region of Taean, South Korea. The morphological, biochemical and molecular characteristics predicted that strain F202Z8^T belongs to the family Flavobacteriaceae. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain F202Z8^T forms a distinct lineage with closely related genera Maribacter, Pelagihabitans, Pseudozobellia, Zobellia, Pricia, and Costertonia and showed the highest similarity to Maribacter aestuarii GY20^T (94.5%). The digital DNA-DNA hybridization and average nucleotide identity values calculated from the whole genome-sequence comparison between strain F202Z8^T and other members of the family Flavobacteriaceae were in the ranges of 12.7%-16.9% and 70.3%-74.4%, respectively, suggesting that strain F202Z8^T represented a novel genus. The complete genome sequence of strain F202Z8^T is 4,723,614 bp, with 43.26% G + C content. Based on the COG, GO, KEGG, NR, and Swiss-Prot databases, the genomic analysis of F202Z8^T revealed the presence of 17 putative genes responsible for the synthesis of AgNPs. Our polyphasic taxonomic results suggested that this strain represents a novel species of a novel genus in the family Flavobacteriaceae, for which the name Aggregatimonas sangjinii gen. nov., sp. nov. is proposed. The type strain of Aggregatimonas sangjinii is F202Z8^T (= KCCM 43411^T = LMG 31494^T). Overall, our data provide fundamental information to potentially utilize this novel bacterium for synthesis of nanoparticles.

Green synthesis of ZrO2 nanoparticles and nanocomposites for biomedical and environmental applications: a review

Pollution and diseases such as the coronavirus pandemic (COVID-19) are major issues that may be solved partly by nanotechnology. Here we review the synthesis of ZrO₂ nanoparticles and their nanocomposites using compounds from bacteria, fungi, microalgae, and plants. For instance, bacteria, microalgae, and fungi secret bioactive metabolites such as fucoidans, digestive enzymes, and proteins, while plant tissues are rich in reducing sugars, polyphenols, flavonoids, saponins, and amino acids. These compounds allow reducing, capping, chelating, and stabilizing during the transformation of Zr⁴⁺ into ZrO₂ nanoparticles. Green ZrO₂ nanoparticles display unique properties such as a nanoscale size of 5-50 nm, diverse morphologies, e.g. nanospheres, nanorods and nanochains, and wide bandgap energy of 3.7-5.5 eV. Their high stability and biocompatibility are suitable biomedical and environmental applications, such as pathogen and cancer inactivation, and pollutant removal. Emerging applications of green ZrO₂-based nanocomposites include water treatment, catalytic reduction, nanoelectronic devices, and anti-biofilms.

Innovative Approaches of Engineering Tumor-Targeting Bacteria with Different Therapeutic Payloads to Fight Cancer: A Smart Strategy of Disease Management

Conventional therapies for cancer eradication like surgery, radiotherapy, and chemotherapy, even though most widely used, still suffer from some disappointing outcomes. The limitations of these therapies during cancer recurrence and metastasis demonstrate the need for better alternatives. Some bacteria preferentially colonize and proliferate inside tumor mass; thus these bacteria can be used as ideal candidates to deliver antitumor therapeutic agents. The bacteria like Bacillus spp., Clostridium spp., E. coli, Listeria spp., and Salmonella spp. can be reprogrammed to produce, transport, and deliver anticancer agents, eg, cytotoxic agents, prodrug converting enzymes, immunomodulators, tumor stroma targeting agents, siRNA, and drug-loaded nanoformulations based on clinical requirements. In addition, these bacteria can be genetically modified to express various functional proteins and targeting ligands that can enhance the targeting approach and controlled drug-delivery. Low tumor-targeting and weak penetration power deep inside the tumor mass limits the use of anticancer drug-nanoformulations. By using anticancer drug nanoformulations and other therapeutic payloads in combination with antitumor bacteria, it makes a synergistic effect against cancer by overcoming the individual limitations. The tumor-targeting bacteria can be either used as a monotherapy or in addition with other anticancer therapies like photothermal therapy, photodynamic therapy, and magnetic field therapy to accomplish better clinical outcomes. The toxicity issues on normal tissues is the main concern regarding the use of engineered antitumor bacteria, which requires deeper research. In this article, the mechanism by which bacteria sense tumor microenvironment, role of some anticancer agents, and the recent advancement of engineering bacteria with different therapeutic payloads to combat cancers has been reviewed. In addition, future prospective and some clinical trials are also discussed.

Marine Macroalgae Display Bioreductant Efficacy for Fabricating Metallic Nanoparticles: Intra/Extracellular Mechanism and Potential Biomedical Applications

The application of hazardous chemicals during nanoparticle (NP) synthesis has raised alarming concerns pertaining to their biocompatibility and equally to the environmental harmlessness. In the recent decade, nanotechnological research has made a gigantic shift in order to include the natural resources to produce biogenic NPs. Within this approach, researchers have utilized marine resources such as macroalgae and microalgae, land plants, bacteria, fungi, yeast, actinomycetes, and viruses to synthesize NPs. Marine macroalgae (brown, red, and green) are rich in polysaccharides including alginates, fucose-containing sulfated polysaccharides (FCSPs), galactans, agars or carrageenans, semicrystalline cellulose, ulvans, and hemicelluloses. Phytochemicals are abundant in phenols, tannins, alkaloids, terpenoids, and vitamins. However, microorganisms have an abundance of active compounds ranging from sugar molecules, enzymes, canonical membrane proteins, reductase enzymes (NADH and NADPH), membrane proteins to many more. The prime reason for using the aforesaid entities in the metallic NPs synthesis is based on their intrinsic properties to act as bioreductants, having the capability to reduce and cap the metal ions into stabilized NPs. Several green NPs have been verified for their biocompatibility in human cells. Bioactive constituents from the above resources have been found on the green metallic NPs, which has demonstrated their efficacies as prospective antibiotics and anti-cancer agents against a range of human pathogens and cancer cells. Moreover, these NPs can be characterized for the size, shapes, functional groups, surface properties, porosity, hydrodynamic stability, and surface charge using different characterization techniques. The novelty and originality of this review is that we provide recent research compilations on green synthesis of NPs by marine macroalgae and other biological sources (plant, bacteria, fungi, actinomycetes, yeast, and virus). Besides, we elaborated on the detailed intra- and extracellular mechanisms of NPs synthesis by marine macroalgae. The application of green NPs as anti-bacterial, anti-cancer, and popular methods of NPs characterization techniques has also been critically reviewed.

Effects of Metallic and Carbon-Based Nanomaterials on Human Pancreatic Cancer Cell Lines AsPC-1 and BxPC-3

Pancreatic cancer, due to its asymptomatic development and drug-resistance, is difficult to cure. As many metallic and carbon-based nanomaterials have shown anticancer properties, we decided to investigate their potential use as anticancer agents against human pancreatic adenocarcinoma. The objective of the study was to evaluate the toxic properties of the following nanomaterials: silver (Ag), gold (Au), platinum (Pt), graphene oxide (GO), diamond (ND), and fullerenol (C₆₀(OH)₄₀) against the cell lines BxPC-3, AsPC-1, HFFF-2, and HS-5. The potential cytotoxic properties were evaluated by the assessment of the cell morphology, cell viability, and cell membrane damage. The cancer cell responses to GO and ND were analysed by determination of changes in the levels of 40 different pro-inflammatory proteins. Our studies revealed that the highest cytotoxicity was obtained after the ND treatment. Moreover, BxPC-3 cells were more sensitive to ND than AsPC-1 cells due to the ND-induced ROS production. Furthermore, in both of the cancer cell lines, ND caused an increased level of IL-8 and a decreased level of TIMP-2, whereas GO caused only decreased levels of TIMP-2 and ICAM-1 proteins. This work provides important data on the toxicity of various nanoparticles against pancreatic adenocarcinoma cell lines.

High Stability Au NPs: From Design to Application in Nanomedicine

In recent years, Au-based nanomaterials are widely used in nanomedicine and biosensors due to their excellent physical and chemical properties. However, these applications require Au NPs to have excellent stability in different environments, such as extreme pH, high temperature, high concentration ions, and various biomatrix. To meet the requirement of multiple applications, many synthetic substances and natural products are used to prepare highly stable Au NPs. Because of this, we aim at offering an update comprehensive summary of preparation high stability Au NPs. In addition, we discuss its application in nanomedicine. The contents of this review are based on a balanced combination of our studies and selected research studies done by worldwide academic groups. First, we address some critical methods for preparing highly stable Au NPs using polymers, including heterocyclic substances, polyethylene glycols, amines, and thiol, then pay attention to natural product progress Au NPs. Then, we sum up the stability of various Au NPs in different stored times, ions solution, pH, temperature, and biomatrix. Finally, the application of Au NPs in nanomedicine, such as drug delivery, bioimaging, photothermal therapy (PTT), clinical diagnosis, nanozyme, and radiotherapy (RT), was addressed concentratedly.

Silver nanoparticles biosynthesized from secondary metabolite producing marine actinobacteria and evaluation of their biomedical potential

Biosynthesis of silver nanoparticles (AgNPs) from marine actinobacteria offers a promising avenue for exploring bacterial extracts as reducing and stabilizing agents. We report extracellular extracts of Rhodococcus rhodochrous (MOSEL-ME29) and Streptomyces sp. (MOSEL-ME28), identified by 16S rRNA gene sequencing for synthesis of AgNPs. Ultrafine silver nanoparticles were biosynthesized using the extracts of R. rhodochrous and Streptomyces sp. and their possible therapeutic applications were studied. The physicochemical properties of nanoparticles were established by HR-SEM/TEM, SAED, UV-Vis, EDS, XRD, and FTIR. UV-Vis spectra displayed characteristic absorption at 430 nm and 412 nm for AgNPs from Streptomyces sp. (S-AgNPs) and Rhodococcus sp. (R-AgNPs), respectively. HR-SEM/TEM, XRD, EDS analysis confirmed the spherical shape, crystalline nature, and elemental formation of silver. Crystallite or grain size was deduced as 5.52 nm for R-AgNPs and 35 nm for S-AgNPs. Zeta-potential indicated electrostatic negative charge for AgNPs, while FTIR revealed the presence of diverse functional groups. Disc diffusion assay indicated the broad-spectrum antibacterial potential of S-AgNPs with the maximum inhibition of B. subtilis while R-AgNPs revealed potency against P. aeruginosa at 10 µg/mL concentration. Biogenic AgNPs revealed antileishmanial activity and the IC₅₀ was calculated as 164 µg/mL and 184 µg/mL for R-AgNPs and S-AgNPs respectively. Similarly, the R-AgNPs and S-AgNPs revealed anti-cancer potential against HepG2 and the IC₅₀ was calculated as 49 µg/mL and 69 µg/mL for R-AgNPs and S-AgNPs, respectively. Moreover, the antioxidant activity showed significant results. MTT assay on RD cells, L20B cells, and Hep-2C indicated intensification in viability by reducing the concentration of R-AgNPs and S-AgNPs. The R-AgNPs and S-AgNPs inhibited sabin-like poliovirus (1TCID₅₀ infection in RD cells). Furthermore, hemocompatibility at low concentrations has been confirmed. Hence, it is concluded that biogenic-AgNPs has the potential to be used in diverse biological applications and that the marine actinobacteria are an excellent resource for fabrication of AgNPs.

Bacteria compete with hematite nanoparticles during their uptake by the ciliate Tetrahymena thermophila

Bacterial accumulation of engineered nanoparticles (NPs) result in their transfer along the food chain. However, there are a lot of NPs not associated with bacteria. Whether bacteria, as representative biotic particles, influence the biological uptake of these non-associated NPs in aquatic ecosystems is unclear. In the present study, we examined the effects of four bacterial species on the uptake kinetics of polyacrylate-coated hematite nanoparticles (HemNPs) by the ciliate Tetrahymena thermophila. The HemNPs were well dispersed. Their adsorption on the bacteria was low with negligible uptake by T. thermophila through bacterial ingestion. This result demonstrated the feasibility of examining the effects of bacteria on the uptake of non-associated HemNPs. Our study further showed that all four bacterial species inhibited the uptake of HemNPs by T. thermophila; however, the effects of the bacterial cells on the physiological activities of the ciliate with respect to its uptake of HemNPs were negligible. In the absence of phagocytosis by T. thermophila, none of the bacteria inhibited HemNP uptake. This observation suggested that bacterial cells competed with the HemNPs for uptake via phagocytosis. Therefore, in evaluations of the environmental risks of NPs, their competition with biotic particles should be taken into account.

Nanoparticles from the Cosmetics and Medical Industries in Legal and Environmental Aspects

This paper presents the application and role of nanomaterials, with particular emphasis on the cosmetics and medical industries. Methods of obtaining materials at the nanoscale and their characteristic structure, which determines their attractiveness and risk, especially in recent years, have been described. The subject of the work was to indicate the hazards and risks that are associated with the properties of nanomaterials; dimension, and high chemical and physical activity, thus making ways to capture and monitor them difficult. Legal and environmental aspects were taken into account, and the involvement of the European Commission in this subject and the activities carried out in a few European countries as well as in Japan, the USA and Canada were analyzed.

Nanoparticles as a Tool for Broadening Antifungal Activities

Fungal infections are diseases that are considered neglected although their infection rates have increased worldwide in the last decades. Thus, since the antifungal arsenal is restricted and many strains have shown resistance, new therapeutic alternatives are necessary. Nanoparticles are considered important alternatives to promote drug delivery. In this sense, the objective of the present study was to evaluate the contributions of newly developed nanoparticles to the treatment of fungal infections. Studies have shown that nanoparticles generally improve the biopharmaceutical and pharmacokinetic characteristics of antifungals, which is reflected in a greater pharmacodynamic potential and lower toxicity, as well as the possibility of prolonged action. It also offers the proposition of new routes of administration. Nanotechnology is known to contribute to a new drug delivery system, not only for the control of infectious diseases but for various other diseases as well. In recent years, several studies have emphasized its application in infectious diseases, presenting better alternatives for the treatment of fungal infections.

Microbial Fabricated Nanosystems: Applications in Drug Delivery and Targeting

The emergence of nanosystems for different biomedical and drug delivery applications has drawn the attention of researchers worldwide. The likeness of microorganisms including bacteria, yeast, algae, fungi, and even viruses toward metals is well-known. Higher tolerance to toxic metals has opened up new avenues of designing microbial fabricated nanomaterials. Their synthesis, characterization and applications in bioremediation, biomineralization, and as a chelating agent has been well-documented and reviewed. Further, these materials, due to their ability to get functionalized, can also be used as theranostics i.e., both therapeutic as well as diagnostic agents in a single unit. Current article attempts to focus particularly on the application of such microbially derived nanoformulations as a drug delivery and targeting agent. Besides metal-based nanoparticles, there is enough evidence wherein nanoparticles have been formulated using only the organic component of microorganisms. Enzymes, peptides, polysaccharides, polyhydroxyalkanoate (PHA), poly-(amino acids) are amongst the most used biomolecules for guiding crystal growth and as a capping/reducing agent in the fabrication of nanoparticles. This has promulgated the idea of complete green chemistry biosynthesis of nano-organics that are most sought after in terms of their biocompatibility and bioavailability.

Micro- and Nanosized Substances Cause Different Autophagy-Related Responses

With rapid industrialization, humans produce an increasing number of products. The composition of these products is usually decomposed. However, some substances are not easily broken down and gradually become environmental pollutants. In addition, these substances may cause bioaccumulation, since the substances can be fragmented into micro- and nanoparticles. These particles or their interactions with other toxic matter circulate in humans via the food chain or air. Whether these micro- and nanoparticles interfere with extracellular vesicles (EVs) due to their similar sizes is unclear. Micro- and nanoparticles (MSs and NSs) induce several cell responses and are engulfed by cells depending on their size, for example, particulate matter with a diameter ≤2.5 μm (PM2.5). Autophagy is a mechanism by which pathogens are destroyed in cells. Some artificial materials are not easily decomposed in organisms. How do these cells or tissues respond? In addition, autophagy operates through two pathways (increasing cell death or cell survival) in tumorigenesis. Many MSs and NSs have been found that induce autophagy in various cells and tissues. As a result, this review focuses on how these particles interfere with cells and tissues. Here, we review MSs, NSs, and PM2.5, which result in different autophagy-related responses in various tissues or cells.

Algal magnetic nickel oxide nanocatalyst in accelerated synthesis of pyridopyrimidine derivatives

This research presents a novel biological route for the biosynthesis of nickel oxide nanoparticles (NiO NPs) using marine macroalgae extract as a reducing and coating agent under optimized synthesis conditions. XRD and TEM analyses revealed that phytosynthesized NiO NPs are crystalline in nature with a spherical shape having a mean particle size of 32.64 nm. TGA results indicated the presence of marine-derived organic constituents on the surface of NiO NPs. It is found that biogenic NiO NPs with BET surface area of 45.59 m²g^-1 is a highly efficient catalyst for benign one-pot preparation of pyridopyrimidine derivatives using aqueous reaction conditions. This environmentally friendly procedure takes considerable advantages of shorter reaction times, excellent product yields (up to 96%), magnetically viable nanocatalyst (7 runs), low catalyst loadings, and free toxic chemical reagents.

Gold nanoparticles: synthesis, physiochemical properties and therapeutic applications in cancer

Gold nanoparticles (AuNPs) have been shown to be useful as carriers of various anticancer drugs as well as diagnosis platforms. In this review, we discuss the synthesis and physiochemical properties of AuNPs. We also highlight the photothermal and photodynamic properties of AuNPs and relevant applications in therapeutic studies. Furthermore, we review the applications of AuNPs in cancer treatment as and their underlying anticancer mechanisms in multiple types of cancer.

A review on biosynthesis of metal nanoparticles and its environmental applications

Nanotechnology has become one of the emerging multi-disciplinary fields receiving universal attention and playing a substantial role in agriculture, environment and pharmacology. In spite of various techniques employed for nanoparticle synthesis such as laser ablation, mechanical milling, spinning and chemical deposition, usage of hazardous chemicals and expensiveness of the process makes it unsuitable for the continuous production. Hence the necessity of sustainable, economic and environment friendly approach development have increased in recent years. Microbial synthesis of nanoparticles connecting microbiology and nanotechnology is one of the green techniques employed for sustainable production. Gold, silver and other metal nanoparticles like platinum, palladium, molybdenum nanoparticles biosynthesis by bacteria, fungi, yeast and algae have been reported in the present review. On account of microbial rich community, several microbes have been explored for the production of nanoparticles. Nanoparticles are also employed for environmental remediation processes such as pollutant removal and detection of contaminants. Lack of monodispersity and prolonged duration of synthesis are the limitations of bio-synthesis process which can be overcome by optimization of methods of microbial cultivation and its extraction techniques. The current review describes the different microbes involved in the synthesis of nanoparticles and its environmental applications.

Biosynthesized Silica Nanosuspension as Thermal Fluid in Parabolic Solar Panels

In this work, the production of biologically synthesized silica nanoparticles was proposed to prepare a nanosuspension as a thermal fluid in parabolic solar panels at the laboratory level. Silica nanoparticles were produced from construction sand in two stages. Biosynthesis broth was produced by Aspergillus niger aerated fermentation in a 1 L bioreactor for 9 days. Each supernatant was contacted with 18% construction sand in a 500 L reactor with mechanical agitation, at a temperature of 25 °C, and a contact time of 30 min. Subsequently, the separation process was carried out. For day 9, a pH value of 1.71 was obtained as well as acid concentrations of 15.78 g/L for citrus and 4.16 g/L for malic. The metal extraction efficiency of Si nanoparticles was 19%. The vibration peaks in the FTIR were characteristic of the presence of silica nanoparticles in wavenumbers 1020 cm⁻¹ and 1150 cm⁻¹. Finally, a prototype solar radiation test bench for parabolic systems was built and provided with a radiation source that falls on a translucent pipe that transports the nanoparticles, which has a pump and a series of thermocouples. The heat capacity of the biotechnologically produced silica nanoparticle suspension was 0.72 ± 0.05 kJ/kgK, using material and energy balances in the flow circuit.

Pterocladiella capillacea-stabilized silver nanoparticles as a green approach toward antibacterial biomaterials

Eco-friendly synthesis of AgNPs using P. capillacea extracts for antibacterial materials.

A newly isolated Bacillus amyloliquefaciens SRB04 for the synthesis of selenium nanoparticles with potential antibacterial properties

The aim of this study was to isolate and characterize marine bacterial strains capable of converting selenite to elemental selenium with the formation of Se nanoparticles (SeNPs). For the first time, a novel marine strain belonging to Bacillus amyloliquefaciens (GenBank accession no. MK392020) was isolated from the coast of the Caspian Sea and characterized based on its ability for transformation of selenite to SeNPs under aerobic conditions. The preliminary formation of SeNPs was confirmed via color changes and the products characterized by UV-Vis spectroscopy. The field-emission scanning electron microscopy (FESEM) together with energy-dispersive X-ray (EDX) analysis showed the presence of the spherical SeNPs on both the surface of the bacterial biomass and in the supernatant solution. Dynamic light scattering (DLS) analysis showed the SeNPs to have an average particle size (Z-average) around 45.4-68.3 nm. The X-ray diffraction (XRD) studies substantiated the amorphous nature of the biosynthesized SeNPs. Fourier-transform infrared spectroscopic (FTIR) studies of the SeNPs indicated typical proteinaceous and lipid-related bands as capping agents on the SeNPs. Different effective parameters corresponding the yield of SeNPs by B. amyloliquefaciens strain SRB04 were optimized under resting cell strategy. Results showed that the optimal process conditions for SeNP production were 2 mM of selenite oxyanion, 20 g/L of cell biomass, and 60 h reaction time. The synthesized SeNPs had a remarkable antibacterial activity on Staphylococcus aureus compared with chloramphenicol as a broad-spectrum antibiotic.

Microbe-Mediated Extracellular and Intracellular Mineralization: Environmental, Industrial, and Biotechnological Applications

Microbe-mediated mineralization is ubiquitous in nature, involving bacteria, fungi, viruses, and algae. These mineralization processes comprise calcification, silicification, and iron mineralization. The mechanisms for mineral formation include extracellular and intracellular biomineralization. The mineral precipitating capability of microbes is often harnessed for green synthesis of metal nanoparticles, which are relatively less toxic compared with those synthesized through physical or chemical methods. Microbe-mediated mineralization has important applications ranging from pollutant removal and nonreactive carriers, to other industrial and biomedical applications. Herein, the different types of microbe-mediated biomineralization that occur in nature, their mechanisms, as well as their applications are elucidated to create a backdrop for future research.