A review on green approaches utilizing phytochemicals in the synthesis of vanadium nano particles and their applications

In the modern era, inorganic nanoparticles have received profound attention as they possess boundless applications in various fields. Among these, vanadium-based nanoparticles (VNPs) are highly remarkable due to their inherent physiological and biological properties with many therapeutic and other applications, such as drug delivery systems for diseases like cancer, environmental remediation, energy storage, energy conversion, and photocatalysis. Moreover, physically, and chemically synthesized VNPs are very versatile, however, these synthesis routes cause concern to health and the environment due to the highly savage reaction conditions, using highly toxic and harsh chemicals, which compel the researchers to develop an eco-friendly, greener, and sustainable route for synthesis. In this outlook, to avoid the innumerable limitations, a bio approach is used over chemical and physical methods. This present review emphasis on the role of various biological components in the synthesis, especially Phyto-molecules that acts as capping and reducing agent, and solvent system for the nanoparticles synthesis. Furthermore, the influence of various factors on the biogenic synthesized nanoparticles has also been discussed. Finally, potential applications of as-synthesized VNPs, principally as an antimicrobial agent and their role as a nanomedicine, energy applications as a supercapacitor, and photocatalytic agents, have been discussed.

How Synthesis of Algal Nanoparticles Affects Cancer Therapy? - A Complete Review of the Literature

The necessity to engineer sustainable nanomaterials for the environment and human health has recently increased. Due to their abundance, fast growth, easy cultivation, biocompatibility and richness of secondary metabolites, algae are valuable biological source for the green synthesis of nanoparticles (NPs). The aim of this review is to demonstrate the feasibility of using algal-based NPs for cancer treatment. Blue-green, brown, red and green micro- and macro-algae are the most commonly participating algae in the green synthesis of NPs. In this process, many algal bioactive compounds, such as proteins, carbohydrates, lipids, alkaloids, flavonoids and phenols, can catalyze the reduction of metal ions to NPs. In addition, many driving factors, including pH, temperature, duration, static conditions and substrate concentration, are involved to facilitate the green synthesis of algal-based NPs. Here, the biosynthesis, mechanisms and applications of algal-synthesized NPs in cancer therapy have been critically discussed. We also reviewed the effective role of algal synthesized NPs as anticancer treatment against human breast, colon and lung cancers and carcinoma.

Application of nanomaterials as potential quorum quenchers for disease: Recent advances and challenges

Chemical signal molecules are used by bacteria to interact with one another. Small hormone-like molecules known as autoinducers are produced, released, detected, and responded to during chemical communication. Quorum Sensing (QS) is the word for this procedure; it allows bacterial populations to communicate and coordinate group behavior. Several research has been conducted on using inhibitors to prevent QS and minimize the detrimental consequences. Through the enzymatic breakdown of the autoinducer component, by preventing the formation of autoinducers, or by blocking their reception by adding some compounds (inhibitors) that can mimic the autoinducers, a technique known as "quorum quenching" (QQ) disrupts microbial communication. Numerous techniques, including colorimetry, electrochemistry, bioluminescence, chemiluminescence, fluorescence, chromatography-mass spectroscopy, and many more, can be used to test QS/QQ. They all permit quantitative and qualitative measurements of QS/QQ molecules. The mechanism of QS and QQ, as well as the use of QQ in the prevention of biofilms, are all elaborated upon in this writing, along with the fundamental study of nanoparticle (NP)in QQ. Q.

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.

Biofabrication of Silver Nanoparticles Using Nostoc muscorum Lukesova 2/91: Optimization, Characterization, and Biological Applications

Purpose

The biological synthesis of nanoparticles (NPs) has become a new methodology for the eco-friendly production of NPs with high scalability and biocompatibility. Cyanobacteria are one of the most widespread microorganisms on Earth and have been proven to be successful biofactories for synthesizing NPs. It is challenging to discover new microalgae with the potential to synthesize NPs of small size with high stability.

Methods

Nostoc muscorum Lukesova 2/91 was isolated, purified, and identified morphologically and genetically using microscopy and DNA sequencing. Volatile biomolecules in aqueous algal extracts were assessed using gas chromatography-mass spectroscopy (GC-MS).

Results

Data showed that the main biomolecules were fatty acids and their esters, followed by secondary metabolites. Algal extract was used to convert silver nitrate (AgNO3) into silver NPs under various optimized parameters. 1 mM of AgNO3, 1:1 (V/V ratio of algal extract to AgNO3), 25 °C, under light illumination, for 24 h, at pH 7.4 were the optimum conditions for NP production (Nos@AgNPs). Nos@AgNPs were characterized using UV-VIS spectroscopy, FTIR, TEM, SEM, EDx, mapping, and a Zetasizer. The wavelength of Nos@AgNPs was 401.4 nm and their shapes were cubic to oval, with an average diameter of 11.8 ± 0.5 nm. FTIR spectroscopy revealed that proteins/polysaccharides could be the main reductants, whereas these molecules and/or fatty acids could be stabilizers for NP synthesis. Nos@AgNPs (86.15%) was silver and had a hydrodynamic diameter of 10.7 nm with a potential charge of -19.7 mV. Antiproliferative and antimicrobial activities of Nos@AgNPs were evaluated. Nos@AgNPs exhibited significant inhibitory activity against lung, colon, and breast cancer cells and considerable biocidal activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa.

Conclusion

N. muscorum Lukesova 2/91 is an excellent source for the biofabrication of small and stable AgNPs with potent inhibitory effects against cancer and bacterial cells.

Biogenic nanoparticles from waste fruit peels: Synthesis, applications, challenges and future perspectives

Nanotechnology is a continually growing field with a wide range of applications from food science to biotechnology and nanobiotechnology. As the current world is grappling with non-biodegradable waste, considered more challenging and expensive to dispose of than biodegradable waste, new technologies are needed today more than ever. Modern technologies, especially nanotechnology, can transform biodegradable waste into products for human use. Researchers are exploring sustainable pathways for nanotechnology by utilizing biodegradable waste as a source for preparing nanomaterials. Over the past ten years, the biogenic production of metallic nanoparticles (NPs) has become a promising alternative technique to traditional NPs synthesis due to its simplicity, eco-friendliness, and biocompatibility in nature. Fruit and vegetable waste (after industrial processing) contain various bioactives (such as flavonoids, phenols, tannins, steroids, triterpenoids, glycosides, anthocyanins, carotenoids, ellagitannins, vitamin C, and essential oils) serving as reducing and capping agents for NP synthesis and they possess antibacterial, antioxidant, and anti-inflammatory properties. This review addresses various sources of biogenic NPs including their synthesis using fruit/vegetable waste, types of biogenic NPs, extraction processes and extracted biomaterials, the pharmacological functionality of NPs, industrial aspects, and future perspectives. In this manner, this review will cover the most recent research on the biogenic synthesis of NPs from fruit/vegetable peels to transform them into therapeutic nanomedicines.

Impact of Diverse Parameters on the Physicochemical Characteristics of Green-Synthesized Zinc Oxide-Copper Oxide Nanocomposites Derived from an Aqueous Extract of Garcinia mangostana L. Leaf

Compared to conventional metal oxide nanoparticles, metal oxide nanocomposites have demonstrated significantly enhanced efficiency in various applications. In this study, we aimed to synthesize zinc oxide-copper oxide nanocomposites (ZnO-CuO NCs) using a green synthesis approach. The synthesis involved mixing 4 g of Zn(NO3)2·6H2O with different concentrations of mangosteen (G. mangostana) leaf extract (0.02, 0.03, 0.04 and 0.05 g/mL) and 2 or 4 g of Cu(NO3)2·3H2O, followed by calcination at temperatures of 300, 400 and 500 °C. The synthesized ZnO-CuO NCs were characterized using various techniques, including a UV-Visible spectrometer (UV-Vis), photoluminescence (PL) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD) analysis and Field Emission Scanning Electron Microscope (FE-SEM) with an Energy Dispersive X-ray (EDX) analyzer. Based on the results of this study, the optical, structural and morphological properties of ZnO-CuO NCs were found to be influenced by the concentration of the mangosteen leaf extract, the calcination temperature and the amount of Cu(NO3)2·3H2O used. Among the tested conditions, ZnO-CuO NCs derived from 0.05 g/mL of mangosteen leaf extract, 4 g of Zn(NO3)2·6H2O and 2 g of Cu(NO3)2·3H2O, calcinated at 500 °C exhibited the following characteristics: the lowest energy bandgap (2.57 eV), well-defined Zn-O and Cu-O bands, the smallest particle size of 39.10 nm with highest surface area-to-volume ratio and crystalline size of 18.17 nm. In conclusion, we successfully synthesized ZnO-CuO NCs using a green synthesis approach with mangosteen leaf extract. The properties of the nanocomposites were significantly influenced by the concentration of the plant extract, the calcination temperature and the amount of precursor used. These findings provide valuable insights for researchers seeking innovative methods for the production and utilization of nanocomposite materials.

Updates on Biogenic Metallic and Metal Oxide Nanoparticles: Therapy, Drug Delivery and Cytotoxicity

The ambition to combat the issues affecting the environment and human health triggers the development of biosynthesis that incorporates the production of natural compounds by living organisms via eco-friendly nano assembly. Biosynthesized nanoparticles (NPs) have various pharmaceutical applications, such as tumoricidal, anti-inflammatory, antimicrobials, antiviral, etc. When combined, bio-nanotechnology and drug delivery give rise to the development of various pharmaceutics with site-specific biomedical applications. In this review, we have attempted to summarize in brief the types of renewable biological systems used for the biosynthesis of metallic and metal oxide NPs and the vital contribution of biogenic NPs as pharmaceutics and drug carriers simultaneously. The biosystem used for nano assembly further affects the morphology, size, shape, and structure of the produced nanomaterial. The toxicity of the biogenic NPs, because of their pharmacokinetic behavior in vitro and in vivo, is also discussed, together with some recent achievements towards enhanced biocompatibility, bioavailability, and reduced side effects. Because of the large biodiversity, the potential biomedical application of metal NPs produced via natural extracts in biogenic nanomedicine is yet to be explored.

Biosynthesis, Characterization, and Antifungal Activity of Novel Trimetallic Copper Oxide-Selenium-Zinc Oxide Nanoparticles against Some Mucorales Fungi

Metal nanoparticles are assumed to be a new generation of biologically active materials. The integrations between more than one metal are synergetic multifunctional features. In the current study, trimetallic copper-selenium-zinc oxide nanoparticles (Tri-CSZ NPs) were successfully mycosynthesized using Aspergillus niger through an ecofriendly method for the first time. The biosynthesis of the particles was characterized using physiochemical and topographical analysis. The physiochemical analysis included Fourier transform infrared spectroscopy (FTIR), which affirmed that the biosynthesis of Tri-CSZ NPs relies on the functional groups of fungal filtrates. Additionally, the UV-visible and X-ray diffraction patterns were proposed for the formation of Tri-CSZ NPs; moreover, topography analysis confirmed that the micromorphology of the nanoparticles were similar to a stick, with ends having a tetragonal pyramid shape, and with an average nanosize of about 26.3 ± 5.4 nm. Cytotoxicity results reveled that the Tri-CSZ NPs have no cytotoxicity on the human normal cell line Wi 38 at low concentrations, where the IC50 was 521 µg/mL. Furthermore, the antifungal activity of the Tri-CSZ NPs was evaluated. The antifungal results revealed that the Tri-CSZ NPs have promising antifungal activity against Mucor racemosus, Rhizopus microsporus, Lichtheimia corymbifera, and Syncephalastrum racemosum, where the minimum inhibitory concentrations (MICs) were 1.95, 7.81, 62.5, and 3.9 µg/mL, and the minimum fungicidal concentrations (MFCs) were 250, 62.5, 125, and 1000 µg/mL, respectively. In conclusion, Tri-CSZ NPs were successfully mycosynthesized using A. niger, which have a promising antifungal activity against fungi causing mucormycosis.

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.

Macroalgae as biofactories of metal nanoparticles; biosynthesis and food applications

Nanotechnology has opened a new frontier in recent years, capable of providing new ways of controlling and structuring products with greater market value and offering significant opportunities for the development of innovative applications in food processing, preservation, and packaging. Macroalgae (MAG) are the major photoautotrophic group of living beings known as a potential source of secondary metabolites, namely phenolic compounds, pigments, and polysaccharides. Biosynthesis based on the abilities of MAG as "nanobiofactories" targets the use of algal secondary metabolites as reducing agents to stabilize nanoparticles (NPs). Nowadays, most of the studies are focused on the use of metal (Ag, Au) and metal-oxide (CuO, ZnO) NPs derived from algae. The eco-friendly biosynthesis of metal NPs reduces the cost and production time and increases their biocompatibility, due to the presence of bioactive compounds in MAG, making them suitable for a wide variety of applications. These compounds have been attributed to the antimicrobial and antioxidant properties responsible for their application through innovative technologies such as nanoencapsulation, nanocomposites, or biosensors in the food industry. Nevertheless, toxicity is a key factor that should be considered, so the applicable regulation needs to guarantee the safe use of metal NPs. Consequently, the aim of this review will be to compile the available information on MAG-mediated metal NPs, their biosynthesis, and potential food applications.

Biofabrication of nanoparticles: sources, synthesis, and biomedical applications

Nanotechnology is an emerging applied science delivering crucial human interventions. Biogenic nanoparticles produced from natural sources have received attraction in recent times due to their positive attributes in both health and the environment. It is possible to produce nanoparticles using various microorganisms, plants, and marine sources. The bioreduction mechanism is generally employed for intra/extracellular synthesis of biogenic nanoparticles. Various biogenic sources have tremendous bioreduction potential, and capping agents impart stability. The obtained nanoparticles are typically characterized by conventional physical and chemical analysis techniques. Various process parameters, such as sources, ions, and temperature incubation periods, affect the production process. Unit operations such as filtration, purification, and drying play a role in the scale-up setup. Biogenic nanoparticles have extensive biomedical and healthcare applications. In this review, we summarized various sources, synthetic processes, and biomedical applications of metal nanoparticles produced by biogenic synthesis. We highlighted some of the patented inventions and their applications. The applications range from drug delivery to biosensing in various therapeutics and diagnostics. Although biogenic nanoparticles appear to be superior to their counterparts, the molecular mechanism degradation pathways, kinetics, and biodistribution are often missing in the published literature, and scientists should focus more on these aspects to move them from the bench side to clinics.

Algal-Derived Synthesis of Silver Nanoparticles Using the Unicellular ulvophyte sp. MBIC10591: Optimisation, Characterisation, and Biological Activities

Algal-mediated synthesis of nanoparticles (NPs) is an eco-friendly alternative for producing NPs with potent physicochemical and biological properties. Microalgae represent an ideal bio-nanofactory because they contain several biomolecules acting as passivation and stabilising agents during the biogenesis of NPs. Herein, a novel microalgae sp. was isolated, purified, and identified using light and electron microscopy and 18s rRNA sequencing. The chemical components of their watery extract were assessed using GC-MS. Their dried biomass was used to synthesise silver (Ag) NPs with different optimisation parameters. Ag-NPs were physiochemically characterised, and their anticancer and antibacterial effects were examined. The data showed that the isolated strain was 99% similar to the unicellular ulvophyte sp. MBIC10591; it was ellipsoidal to spherical and had a large cup-shaped spongiomorph chloroplast. The optimum parameters for synthesising Ag-NPs by unicellular ulvophyte sp. MBIC10591 (Uv@Ag-NPs) were as follows: mixture of 1 mM of AgNO₃ with an equal volume of algal extract, 100 °C for 1 h, and pH of 7 under illumination for 24 h. TEM, HRTEM, and SEM revealed that Uv@Ag-NPs are cubic to spherical, with an average nanosize of 12.1 ± 1.2 nm. EDx and mapping analysis showed that the sample had 79% of Ag, while FTIR revealed the existence of several functional groups on the NP surface derivatives from the algal extract. The Uv@Ag-NPs had a hydrodynamic diameter of 178.1 nm and a potential charge of -26.7 mV and showed marked antiproliferative activity against PC3, MDA-MB-231, T47D, and MCF-7, with IC₅₀ values of 27.4, 20.3, 23.8, and 40 µg/mL, respectively, and moderate toxicity against HFs (IC₅₀ of 13.3 µg/mL). Uv@Ag-NPs also showed marked biocidal activity against Gram-negative bacteria. Escherichia coli was the most sensitive bacteria to the NPs with an inhibition zone of 18.9 ± 0.03 mm. The current study reports, for the first time, the morphological appearance of the novel unicellular ulvophyte sp., MBIC10591, and its chemical composition and potential to synthesise Uv@Ag-NPs with smaller sizes and high stability to act as anti-tumour and microbial agents.

Effect of Calcination Temperature on Structural, Morphological and Optical Properties of Copper Oxide Nanostructures Derived from Garcinia mangostana L. Leaf Extract

Synthesis of copper oxide (CuO) nanostructures via biological approach has gained attention to reduce the harmful effects of chemical synthesis. The CuO nanostructures were synthesized through a green approach using the Garcinia mangostana L. leaf extract and copper (II) nitrate trihydrate as a precursor at varying calcination temperatures (200-600 °C). The effect of calcination temperatures on the structural, morphological and optical properties of CuO nanostructures was studied. The red shifting of the green-synthesized CuO nanoparticles' absorption peak was observed in UV-visible spectrum, and the optical energy bandgap was found to decrease from 3.41 eV to 3.19 eV as the calcination temperatures increased. The PL analysis shown that synthesized CuO NPs calcinated at 500 °C has the maximum charge carriers separation. A peak located at 504-536 cm^-1 was shown in FTIR spectrum that indicated the presence of a copper-oxygen vibration band and become sharper and more intense when increasing the calcination temperature. The XRD studies revealed that the CuO nanoparticles' crystalline size was found to increase from 12.78 nm to 28.17 nm, and dislocation density decreased from 61.26 × 10¹⁴ cm^-1 to 12.60 × 10¹⁴ cm^-1, while micro strain decreased from 3.40 × 10^-4 to 1.26 × 10^-4. From the XPS measurement, only CuO single phase without impurities was detected for the green-mediated NPs calcinated at 500 °C. The morphologies of CuO nanostructures were examined using FESEM and became more spherical in shape at elevated calcination temperature. More or less spherical nanostructure of green-mediated CuO calcinated at 500 °C were also observed using TEM. The purity of the green-synthesized CuO nanoparticles was evaluated by EDX analysis, and results showed that increasing calcination temperature increases the purity of CuO nanoparticles.

Smart and Multi-Functional Magnetic Nanoparticles for Cancer Treatment Applications: Clinical Challenges and Future Prospects

Iron oxide nanoparticle (IONPs) have become a subject of interest in various biomedical fields due to their magnetism and biocompatibility. They can be utilized as heat mediators in magnetic hyperthermia (MHT) or as contrast media in magnetic resonance imaging (MRI), and ultrasound (US). In addition, their high drug-loading capacity enabled them to be therapeutic agent transporters for malignancy treatment. Hence, smartening them allows for an intelligent controlled drug release (CDR) and targeted drug delivery (TDD). Smart magnetic nanoparticles (SMNPs) can overcome the impediments faced by classical chemo-treatment strategies, since they can be navigated and release drug via external or internal stimuli. Recently, they have been synchronized with other modalities, e.g., MRI, MHT, US, and for dual/multimodal theranostic applications in a single platform. Herein, we provide an overview of the attributes of MNPs for cancer theranostic application, fabrication procedures, surface coatings, targeting approaches, and recent advancement of SMNPs. Even though MNPs feature numerous privileges over chemotherapy agents, obstacles remain in clinical usage. This review in particular covers the clinical predicaments faced by SMNPs and future research scopes in the field of SMNPs for cancer theranostics.

Silver nanoparticles synthesized from the seaweed Sargassum polycystum and screening for their biological potential

World-wide antimicrobial resistant is biggest threat in global health. It requires the urgent need of multisectoral action for the scientific community to achieve the sustainable development Goals. Due to their antimicrobial properties, silver nanoparticles are potential activates to pathogens, which explains their potential for multiple applications in various fields. In the present studies, we evaluate the antimicrobial properties of a Sargassum polycystum algal extract, an unrivaled green synthetic method for producing -defined shaped seaweed silver nanoparticles. To confirm their structure and size, some characterization techniques are used, such as Absorption spectrophotometer (UV-VIS), Fourier transforms infrared spectroscopy (FTIR), Scanning electron Microscope (SEM), Transmission electron microscopy (TEM) and X-Ray diffraction (XRD). Evaluate the antibacterial and anti-mycobacterial activity using silver nanoparticles. The toxicity study of this silver nanoparticle has been done with the help of zebrafish larva. The biological nanoparticle having good antimicrobial activity against Staphylococcus aureus, Micrococcus luteus, Pseudomonas fluorescens and Candida albicans and also it shows potent activity against MTB H37Rv, SHRE sensitive MTB Rifampicin resistant MTB around 98%. Seaweed nanoparticles had lower toxicity for the survival of the fish larvae. In comparison, other dosages will arrest the cell cycle and leads to death. The present finding revealed that these seaweeds nanoparticles have potential anti-mycobacterial activity against pathogens at low concentrations. This makes them a potent source of antibacterial and anti-TB agents.

Biogenic Synthesis of ZnO Nanoparticles and Their Application as Bioactive Agents: A Critical Overview

Zinc oxide is a safe material for humans, with high biocompatibility and negligible cytotoxicity. Interestingly, it shows exceptional antimicrobial activity against bacteria, viruses, fungi, etc., especially when reduced to the nanometer size. As it is easily understandable, thanks to its properties, it is at the forefront of safe antimicrobials in this pandemic era. Besides, in the view of the 2022 European Green Deal announced by the European Commission, even science and nanotechnology are moving towards “greener” approaches to the synthesis of nanoparticles. Among them, biogenic ZnO nanoparticles have been extensively studied for their biological applications and environmental remediation. Plants, algae, fungi, yeast, etc., (which are composed of naturally occurring biomolecules) play, in biogenic processes, an active role in the formation of nanoparticles with distinct shapes and sizes. The present review targets the biogenic synthesis of ZnO nanoparticles, with a specific focus on their bioactive properties and antimicrobial application.

Phyco-Synthesized Zinc Oxide Nanoparticles Using Marine Macroalgae, Ulva fasciata Delile, Characterization, Antibacterial Activity, Photocatalysis, and Tanning Wastewater Treatment

The aqueous extract of marine green macroalgae, Ulva fasciata Delile, was harnessed for the synthesis of zinc oxide nanoparticles (ZnO-NPs). The conversion to ZnO-NPs was characterized by color change, UV–vis spectroscopy, FT-IR, TEM, SEM-EDX, and XRD. Data showed the formation of spherical and crystalline ZnO-NPs with a size range of 3–33 nm. SEM-EDX revealed the presence of Zn and O in weight percentages of 45.3 and 31.62%, respectively. The phyco-synthesized ZnO-NPs exhibited an effective antibacterial activity against the pathogenic Gram-positive and Gram-negative bacteria. The bacterial clear zones ranged from 21.7 ± 0.6 to 14.7 ± 0.6 mm with MIC values of 50–6.25 µg mL−1. The catalytic activity of our product was investigated in dark and visible light conditions, using the methylene blue (MB) dye. The maximum dye removal (84.9 ± 1.2%) was achieved after 140 min in the presence of 1.0 mg mL−1 of our nanocatalyst under the visible light at a pH of 7 and a temperature of 35 °C. This percentage was decreased to 53.4 ± 0.7% under the dark conditions. This nanocatalyst showed a high reusability with a decreasing percentage of ~5.2% after six successive cycles. Under the optimum conditions, ZnO-NPs showed a high efficacy in decolorizing the tanning wastewater with a percentage of 96.1 ± 1.7%. Moreover, the parameters of the COD, BOD, TSS, and conductivity were decreased with percentages of 88.8, 88.5, 96.9, and 91.5%, respectively. Moreover, nano-ZnO had a high efficacy in decreasing the content of the tanning wastewater Cr (VI) from 864.3 ± 5.8 to 57.3 ± 4.1 mg L−1 with a removal percentage of 93.4%.

Green Synthesis of Metal Oxides Semiconductors for Gas Sensing Applications

During recent decades, metal oxide semiconductors (MOS) have sparked more attention in various applications and industries due to their excellent sensing characteristics, thermal stability, abundance, and ease of synthesis. They are reliable and accurate for measuring and monitoring environmentally important toxic gases, such as NO₂, NO, N₂O, H₂S, CO, NH₃, CH₄, SO₂, and CO₂. Compared to other sensing technologies, MOS sensors are lightweight, relatively inexpensive, robust, and have high material sensitivity with fast response times. Green nanotechnology is a developing branch of nanotechnology and aims to decrease the negative effects of the production and application of nanomaterials. For this purpose, organic solvents and chemical reagents are not used to prepare metal nanoparticles. On the contrary, the synthesis of metal or metal oxide nanoparticles is done by microorganisms, either from plant extracts or fungi, yeast, algae, and bacteria. Thus, this review aims at illustrating the possible green synthesis of different metal oxides such as ZnO, TiO₂, CeO₂, SnO₂, In₂O₃, CuO, NiO, WO_3, and Fe₃O₄, as well as metallic nanoparticles doping.

Anticancer and Antimicrobial Activity of Red Sea Seaweeds Extracts-Mediated Gold Nanoparticles

Biosynthesis of gold nanoparticles (AuNPs) is emerging as a better alternative to traditional chemical-based techniques. During this study, extracts of different marine algae species Ulva rigida (green algae), Cystoseira myrica (brown Algae), and Gracilaria foliifera (red Algae) were utilized as reducing and capping agents to synthesize AuNPs. AuNPs capped by U. rigida, C. myrica, and G. foliifera were confirmed by the appearance of surface plasmonic bands at 528, 540, and 543 nm, respectively. Transmission electron microscopy revealed mostly spherical shapes of AuNPs having a size of about 9 nm, 11 nm, and 13 nm for C. myrica, and G. foliifera extracts, respectively. Fourier transform-infrared spectroscopy (FTIR) illustrated the major chemical constituents of U. rigida, C. myrica, and G. foliifera. LC50 values of the biosynthesized AuNPs against Artemia salina nauplii were calculated at a range of concentrations (5-188 μg ml−1) after 16 to 24h. AuNPs concentration-dependent lethality was noted and U. rigida extracts-mediated AuNPs presented the lowest cytotoxicity. The biosynthesized AuNPs exhibited significant anticancer activity (86.83%) against MCF-7 cell lines (human breast adenocarcinoma cell lines) at 188 µg/ml concentration. G. foliifera demonstrated the highest anticancer value (92.13%) followed by C. myrica (89.82%), and U. rigida (86.83%), respectively. The AuNPs synthesized by different algal extracts showed variable antimicrobial activity against the tested pathogenic microorganisms. AuNPs of U. rigida extracts showed significant antimicrobial activity against dermatophytic fungi Trichosporon cataneum (30 mm) followed by Trichophyton mantigrophytes (25 mm). Furthermore, it also exhibited mild activity against Escherichia coli (17 mm), Cryptococcus neoformans (15 mm), Candida albicans (13 mm), and Staphylococcus aureus (11mm), respectively whereas no effects were observed against Bacillus cereus. To conclude, AuNPs can be effectively synthesized by marine algal species, and particularly U. rigida extracts could be effective reducing agents for the green AuNPs synthesis. These AuNPs could potentially serve as efficient alternative anticancer agents against human breast adenocarcinoma and anti-dermatophytes associated with skin infections.

Synthesis, Characterization and Biomedical Application of Silver Nanoparticles

Silver nanoparticles (AgNPs) have been employed in various fields of biotechnology due to their proven properties as an antibacterial, antiviral and antifungal agent. AgNPs are generally synthesized through chemical, physical and biological approaches involving a myriad of methods. As each approach confers unique advantages and challenges, a trends analysis of literature for the AgNPs synthesis using different types of synthesis were also reviewed through a bibliometric approach. A sum of 10,278 publications were analyzed on the annual numbers of publication relating to AgNPs and biological, chemical or physical synthesis from 2010 to 2020 using Microsoft Excel applied to the Scopus publication database. Furthermore, another bibliometric clustering and mapping software were used to study the occurrences of author keywords on the biomedical applications of biosynthesized AgNPs and a total collection of 224 documents were found, sourced from articles, reviews, book chapters, conference papers and reviews. AgNPs provides an excellent, dependable, and effective solution for seven major concerns: as antibacterial, antiviral, anticancer, bone healing, bone cement, dental applications and wound healing. In recent years, AgNPs have been employed in biomedical sector due to their antibacterial, antiviral and anticancer properties. This review discussed on the types of synthesis, how AgNPs are characterized and their applications in biomedical field.

Evaluation of algal active compounds as potent antibiofilm agent

Biofilm is the syntrophic association of microbial colonies that remain adhered to the biotic and abiotic surfaces with the help of self-secreted polymeric substances also termed extracellular polymeric substances. Chronic pathogenicity caused by biofilm-associated pathogenic microorganisms becomes a significant threat in biomedical research. An extensive search is being made for the antibiofilm agents made from natural sources or their biogenic derivatives due to their effectivity and nontoxicity. Algae being the producer of various biogenic substances are found capable of disintegrating biofilm matrix and eradication of biofilm without exerting any deterrent effect on other biotas in the ecosystem. The current trend in phycological studies includes the exploration of antifouling efficacy among various algal groups. The extracts prepared from about 225 microalgae and cyanobacteria species are found to have antibiofilm activity. Polyunsaturated fatty acids are the most important component in the algal extract with antibacterial and antibiofilm properties. The antibiofilm activity of the sulfated polysaccharides extracted from a marine alga could be effectively used to remove dental biofilm. Algal extracts are also being used for the preparation of different biogenically synthesized nanoparticles, which are being used as potent antibiofilm agents. Genome editing of algal species by CRISPR/Cas9 may make precise modifications in the algal DNA for improving the algal strains and production of a more effective antibiofouling agent.

Sustainable and green trends in using plant extracts for the synthesis of biogenic metal nanoparticles toward environmental and pharmaceutical advances: A review

Conventionally utilized physical and chemical routes for constructing nanoparticles are not eco-friendly. They are associated with many shortcomings like the requirement of specially designed equipment, templates, extremely high temperature, and pressure. Biosynthesis seems to be drawn unequivocal attention owing to its upsurge of applications in different fields like; energy, nutrition, pharmaceutical, and medicinal sciences. To harness the biological sources, the present review describes an environment-friendly route to generate biogenic nanoparticles from the natural plant extracts and the followed mechanisms for their synthesis, growth, and stabilization. The present review summarizes the recent trends involved in the photosynthesis of metallic nanoparticles and their effective use in controlling malaria, hepatitis, cancer, like various endemic diseases. Also, various characterization approaches, such as UV-visible spectrophotometry, Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy, are discussed here examine the properties of as-fabricated nanoparticles. Various plant parts like leaves, stems, barks, fruit, and flowers are rich in flavonoids, phenols, steroids, terpenoids, enzymes, and alkaloids, thereby playing an essential role in reducing metal ions that generate metallic nanoparticles. Herein, the uniqueness of phytofabricated nanoparticles along with their distinctive antibacterial, antioxidant, cytotoxic, and drug delivery properties are featured. Lastly, this work highlights the various challenges and future perspectives to further synthesize biogenic metal nanoparticles toward environmental and pharmaceutical advances in the coming years.

Zinc phosphate nanoparticles: A review on physical, chemical, and biological synthesis and their applications

Nanotechnology is considered one of the emerging fields of science that has influenced diverse applications, including food, biomedicine, and cosmetics. The production and usage of materials with nanoscale dimensions like nanoparticles are attractive parts of nanotechnology. Among different nanoparticles, zinc phosphate nanoparticles have attracted attention due to their biocompatibility, biosafety, non-toxicity, and environmental compatibility. These nanoparticles could be employed in various applications like anticorrosion, antibacterial, dental cement, glass ceramics, tissue engineering, and drug delivery. A variety of physical, chemical, and green synthesis methods have been used to synthesize zinc phosphate nanoparticles. All these methods have some limitations along with certain advantages. Chemical approaches may cause health risks and environmental problems due to the toxicity of hazardous chemicals used in these techniques. Moreover, physical methods require high amounts of energy as well as expensive instruments. However, biological methods are free of chemical contaminants and eco-friendly. This review is aimed to explore different methods for the synthesis of zinc phosphate nanoparticles, including physical, chemical, and more recently, biological approaches (using various sources such as plants, algae, and microorganisms). Also, it summarizes the practicable applications of zinc phosphate nanoparticles as anticorrosion pigment, dental cement, and drug delivery agents.

Phytofabricated zinc oxide nanoparticles as a nanofungicide for management of Alternaria blight of Brassica

Plant pathogens resistant to the commercially available fungicides and bactericides even at higher concentrations are the biggest challenge for the farmers to control the losses due to plant diseases. The antibacterial and antifungal potential of nanomaterials makes them a suitable candidate for the control of plant diseases. Thus, the present study reports the phytofabricated zinc oxide nanoparticles (ZnO Np's) using aqueous plant leaf extract of Terminalia bellerica (Baheda). Characterization of ZnO nanoparticles was done by ultraviolet-visible (UV-Vis) studies, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infra-red (FT-IR) analysis, and transmission electron microscopy (TEM). The presence of pure hexagonal wurtzite crystalline structure of ZnO nanoparticles was confirmed by XRD analysis. The TEM images revealed the spherical to hexagonal shaped ZnO nanoparticles with sizes ranging from 20 to 30 nm. The stabilization of synthesized ZnO nanoparticles through the interactions of terpenoids, steroids, phenylpropanoids, flavonoids, phenolic acids, and enzymes present in the leaf extract was suggested by FTIR analysis. The mechanism of the formation of ZnO nanoparticles using Terminalia bellerica (Baheda) (Tb-ZnO Np's) as a bioactive compound is proposed. These phytofabricated ZnO nanoparticles (Tb-ZnO Np's) have shown significant antifungal potential against Alternaria brassicae the causal agent of Alternaria blight disease/leaf spot disease in Brassica species. The microscopic results confirm the changes in mycelium morphology and reduction in the number of spore germination at 0.2 mg/mL concentration Tb-ZnO Np's.

Marine Algae-Derived Bioactive Compounds: A New Wave of Nanodrugs?

Marine algae are rich in bioactive nutraceuticals (e.g., carbohydrates, proteins, minerals, fatty acids, antioxidants, and pigments). Biotic (e.g., plants, microorganisms) and abiotic factors (e.g., temperature, pH, salinity, light intensity) contribute to the production of primary and secondary metabolites by algae. Easy, profitable, and sustainable recovery methods include novel solid-liquid and liquid-liquid extraction techniques (e.g., supercritical, high pressure, microwave, ultrasound, enzymatic). The spectacular findings of algal-mediated synthesis of nanotheranostics has attracted further interest because of the availability of microalgae-based natural bioactive therapeutic compounds and the cost-effective commercialization of stable microalgal drugs. Algal extracts can serve as stabilizing/capping and reducing agents for the synthesis of thermodynamically stable nanoparticles (NPs). Different types of nanotherapeutics have been synthesized using physical, chemical, and biological methods. Marine algae are a fascinating source of lead theranostics compounds, and the development of nanotheranostics has been linked to enhanced drug efficacy and safety. Indeed, algae are remarkable nanobiofactories, and their pragmatic properties reside in their (i) ease of handling; (ii) capacity to absorb/accumulate inorganic metallic ions; (iii) cost-effectiveness; and (iv) capacity of eco-friendly, rapid, and healthier synthesis of NPs. Preclinical and clinical trials shall enable to really define effective algal-based nanotherapies. This review aims to provide an overview of the main algal compounds that are nutraceuticals and that can be extracted and purified for nanotheranostic purposes.

A Review of Green Synthesis of Metal Nanoparticles Using Algae

The ability of algae to accumulate metals and reduce metal ions make them a superior contender for the biosynthesis of nanoparticles and hence they are called bio-nano factories as both the live and dead dried biomass are used for the synthesis of metallic nanoparticles. Microalgae, forming a substantial part of the planet's biodiversity, are usually single-celled colony-forming or filamentous photosynthetic microorganisms, including several legal divisions like Chlorophyta, Charophyta, and Bacillariophyta. Whole cells of Plectonema boryanum (filamentous cyanobacteria) proved efficient in promoting the production of Au, Ag, and Pt nanoparticles. The cyanobacterial strains of Anabaena flos-aquae and Calothrix pulvinate were used to implement the biosynthesis of Au, Ag, and Pt nanoparticles. Once synthesized within the cells, the nanoparticles were released into the culture media where they formed stable colloids easing their recovery. Lyngbya majuscule and Chlorella vulgaris have been reported to be used as a cost-effective method for Ag nanoparticle synthesis. Dried edible algae (Spirulina platensis) was reported to be used for the extracellular synthesis of Au, Ag, and Au/Ag bimetallic nanoparticles. Synthesis of extracellular metal bio-nanoparticles using Sargassum wightii and Kappaphycus alvarezi has also been reported. Bioreduction of Au (III)-Au (0) using the biomass of brown alga, Fucus vesiculosus, and biosynthesis of Au nanoparticles using red algal (Chondrus crispus) and green algal (Spyrogira insignis) biomass have also been reported. Algae are relatively convenient to handle, less toxic, and less harmful to the environment; synthesis can be carried out at ambient temperature and pressure and in simple aqueous media at a normal pH value. Therefore, the study of algae-mediated biosynthesis of metallic nanoparticles can be taken toward a new branch, termed phyco-nanotechnology.

Green Synthesis, Structural Characterization and Photocatalytic Applications of ZnO Nanoconjugates Using Heliotropium indicum

In recent years, biosynthesized zinc oxide nanoparticles (ZnO NPs) have been gaining importance due to their unique properties and tremendous applications. This study aimed to fabricate ZnO NPs by using extracts from various parts of the traditional medicinal plant Heliotropium indicum (H. indicum) and evaluate their photocatalytic activity. Further, their potential in photoluminescence and fluorescence resonance energy transfer (FRET) was assessed. The Ultraviolet-Visible spectrum exhibited a hypsochromic shifted absorption band between 350–380 nm. Transmission electron microscopy (TEM) analysis revealed spherical NPs, while X-ray diffraction (XRD) data revealed wurtzite, hexagonal and crystalline nature. The TEM and XRD consistently determined an average particle size range from 19 to 53 nm. The photocatalytic degradation reaches a maximum of 95% for biogenic ZnO NPs by monitoring spectrophotometrically the degradation of methylene blue dye (λmax = 662.8 nm) under solar irradiation. Photoluminescence analysis revealed differentiated spectra with high-intensity emission peaks for biogenic ZnO NPs compared with chemically synthesized ZnO NPs. Eventually, the highest efficiency of FRET (80%) was found in ZnO NPs synthesized from the leaves. This remains the first report highlighting the multifunctional ZnO NPs capabilities mediated by using H. indicum, which could lead to important potential environmental and biomedical applications.

Microbe-Mediated Biosynthesis of Nanoparticles: Applications and Future Prospects

Nanotechnology is the science of nano-sized particles/structures (~100 nm) having a high surface-to-volume ratio that can modulate the physical, chemical and biological properties of the chemical compositions. In last few decades, nanoscience has attracted the attention of the scientific community worldwide due to its potential uses in the pharmacy, medical diagnostics and disease treatment, energy, electronics, agriculture, chemical and space industries. The properties of nanoparticles (NPs) are size and shape dependent. These characteristic features of nanoparticles can be explored for various other applications such as computer transistors, chemical sensors, electrometers, memory schemes, reusable catalysts, biosensing, antimicrobial activity, nanocomposites, medical imaging, tumor detection and drug delivery. Therefore, synthesizing nanoparticles of desired size, structure, monodispersity and morphology is crucial for the aforementioned applications. Recent advancements in nanotechnology aim at the synthesis of nanoparticles/materials using reliable, innoxious and novel ecofriendly techniques. In contrast to the traditional methods, the biosynthesis of nanoparticles of a desired nature and structure using the microbial machinery is not only quicker and safer but more environmentally friendly. Various microbes, including bacteria, actinobacteria, fungi, yeast, microalgae and viruses, have recently been explored for the synthesis of metal, metal oxide and other important NPs through intracellular and extracellular processes. Some bacteria and microalgae possess specific potential to fabricate distinctive nanomaterials such as exopolysaccharides, nanocellulose, nanoplates and nanowires. Moreover, their ability to synthesize nanoparticles can be enhanced using genetic engineering approaches. Thus, the use of microorganisms for synthesis of nanoparticles is unique and has a promising future. The present review provides explicit information on different strategies for the synthesis of nanoparticles using microbial cells; their applications in bioremediation, agriculture, medicine and diagnostics; and their future prospects.

Al-Suhaimi E, Hussain M, Yousuf Bari M, Mehmood Ali S, Al-Jameel SS, Slimani Y, Khan FA, Baykal A. Ultrasonic Synthesis and Biomedical Application of Mn0.5Zn0.5ErxYxFe2-2xO4 Nanoparticles

In the present study, biocompatible manganese nanoparticles have been linked with zinc and iron molecules to prepare different derivatives of Mn_0.5Zn_0.5Er_xY_xFe_2-2xO₄ NPs (x = 0.02, 0.04, 0.06, 0.08, 0.10), using an ultrasonication approach. The structure, surface morphology, and chemical compositions of Mn_0.5Zn_0.5Er_xY_xFe_2-2xO₄ NPs were elucidated by X-ray diffractometer (XRD), High-resolution transmission electron microscopy (HR-TEM), scanning electron microscope (SEM), and Energy Dispersive X-Ray Analysis (EDX) techniques. The bioactivity of Mn_0.5Zn_0.5Er_xY_xFe_2-2xO₄ NPs on normal (HEK-293) and (HCT-116) colon cancer cell line was evaluated. The Mn_0.5Zn_0.5Er_xY_xFe_2-2xO₄ NPs treatment post 48 h resulted in a significant reduction in cells (via MTT assay, having an IC₅₀ value between 0.88 µg/mL and 2.40 µg/mL). The specificity of Mn_0.5Zn_0.5Er_xY_xFe_2-2xO₄ NPs were studied by treating them on normal cells line (HEK-293). The results showed that Mn_0.5Zn_0.5Er_xY_xFe_2-2xO₄ NPs did not incur any effect on HEK-293, which suggests that Mn_0.5Zn_0.5Er_xY_xFe_2-2xO₄ NPs selectively targeted the colon cancerous cells. Using Candida albicans, antifungal activity was also studied by evaluating minimum inhibitory/fungicidal concentration (MIC/MFC) and the effect of nanomaterial on the germ tube formation, which exhibited that NPs significantly inhibited the growth and germ tube formation. The obtained results hold the potential to design nanoparticles that lead to efficient bioactivity.

Biogenic Nanoparticles: Synthesis, Characterisation and Applications

Nanotechnology plays a big part in our modern daily lives, ranging from the biomedical sector to the energy sector. There are different physicochemical and biological methods to synthesise nanoparticles towards multiple applications. Biogenic production of nanoparticles through the utilisation of microorganisms provides great advantages over other techniques and is increasingly being explored. This review examines the process of the biogenic synthesis of nanoparticles mediated by microorganisms such as bacteria, fungi and algae, and their applications. Microorganisms offer a disparate environment for nanoparticle synthesis. Optimum production and minimum time to obtain the desired size and shape, to improve the stability of nanoparticles and to optimise specific microorganisms for specific applications are the challenges to address, however. Numerous applications of biogenic nanoparticles in medicine, environment, drug delivery and biochemical sensors are discussed.

Synergistic effects of combinatorial chitosan and polyphenol biomolecules on enhanced antibacterial activity of biofunctionalaized silver nanoparticles

The present study reports the synergistic antibacterial activity of biosynthesized silver nanoparticles (AgNPs) with the aid of a combination of chitosan and seaweed-derived polyphenols as a green synthetic route. Under optimum synthesis conditions, the rapid color change from yellowish to dark brown and UV-visible absorption peak at 425 confirmed the initial formation of AgNPs. DLS, TEM, XRD, and EDX analyses revealed the spherical shape of pure biogenic AgNPs with a mean diameter size of 12 nm ± 1.5 nm, and a face-centered cubic crystal structure, respectively. FTIR and TGA results indicated the significant contribution of chitosan and polyphenol components into silver ions bioreduction and thermal stability of freshly formed AgNPs. Long-term colloidal stability of AgNPs was obtained after 6-month storage at room temperature. The bio-prepared AgNPs possessed a negative surface charge with a zeta potential value of - 27 mV. In contrast to naked chemical silver nanoparticles, the green Ag nanosamples demonstrated the distinct synergistic antibacterial in vitro toward all selected human pathogens presumably due to the presence of high content of biomolecules on their surface. The results show that synergy between chitosan and polyphenol results in the enhancement of bactericidal properties of biogenic AgNPs. We also highlighted the underlying mechanism involved in AgNPs formation based on nucleophile-electrophile interaction.

An Overview of the Algae-Mediated Biosynthesis of Nanoparticles and Their Biomedical Applications

Algae have long been exploited commercially and industrially as food, feed, additives, cosmetics, pharmaceuticals, and fertilizer, but now the trend is shifting towards the algae-mediated green synthesis of nanoparticles (NPs). This trend is increasing day by day, as algae are a rich source of secondary metabolites, easy to cultivate, have fast growth, and are scalable. In recent era, green synthesis of NPs has gained widespread attention as a safe, simple, sustainable, cost-effective, and eco-friendly protocol. The secondary metabolites from algae reduce, cap, and stabilize the metal precursors to form metal, metal oxide, or bimetallic NPs. The NPs synthesis could either be intracellular or extracellular depending on the location of NPs synthesis and reducing agents. Among the diverse range of algae, the most widely investigated algae for the biosynthesis of NPs documented are brown, red, blue-green, micro and macro green algae. Due to the biocompatibility, safety and unique physico-chemical properties of NPs, the algal biosynthesized NPs have also been studied for their biomedical applications, which include anti-bacterial, anti-fungal, anti-cancerous, anti-fouling, bioremediation, and biosensing activities. In this review, the rationale behind the algal-mediated biosynthesis of metallic, metallic oxide, and bimetallic NPs from various algae have been reviewed. Furthermore, an insight into the mechanism of biosynthesis of NPs from algae and their biomedical applications has been reviewed critically.

Natural Metallic Nanoparticles for Application in Nano-Oncology

Here, the various types of naturally synthesized metallic nanoparticles, which are essentially composed of Ce, Ag, Au, Pt, Pd, Cu, Ni, Se, Fe, or their oxides, are presented, based on a literature analysis. The synthesis methods used to obtain them most often involve the reduction of metallic ions by biological materials or organisms, i.e., essentially plant extracts, yeasts, fungus, and bacteria. The anti-tumor activity of these nanoparticles has been demonstrated on different cancer lines. They rely on various mechanisms of action, such as the release of chemotherapeutic drugs under a pH variation, nanoparticle excitation by radiation, or apoptotic tumor cell death. Among these natural metallic nanoparticles, one type, which consists of iron oxide nanoparticles produced by magnetotactic bacteria called magnetosomes, has been purified to remove endotoxins and abide by pharmacological regulations. It has been tested in vivo for anti-tumor efficacy. For that, purified and stabilized magnetosomes were injected in intracranial mouse glioblastoma tumors and repeatedly heated under the application of an alternating magnetic field, leading to the full disappearance of these tumors. As a whole, the results presented in the literature form a strong basis for pursuing the efforts towards the use of natural metallic nanoparticles for cancer treatment first pre-clinically and then clinically.

Fruit and Vegetable Peels: Utilization of High Value Horticultural Waste in Novel Industrial Applications

Fruits and vegetables are the highly used food products amongst the horticultural crops. These items are consumed uncooked, nominally cooked or fully cooked, according to their nature and cooking process. With the change in diet habits and rising population, the production, as well as the processing of horticultural crops, has exponentially improved to meet its increasing demand. A large amount of peel waste is generated from fruit and vegetable-based industries and household kitchen and has led to a big nutritional and economic loss and environmental problems. Processing of fruits and vegetables alone generates a significant waste, which amounts to 25-30% of the total product. Most common wastes include pomace, peels, rind and seeds, which are highly rich in valuable bioactive compounds such as carotenoids, enzymes, polyphenols, oils, vitamins and many other compounds. These bioactive compounds show their application in various industries such as food to develop edible films, food industries for probiotics and other industries for valuable products. The utilization of these low-cost waste horticultural wastes for producing the value-added product is a novel step in its sustainable utilization. The present review intends to summarize the different types of waste originating from fruits as well as vegetables peels and highlight their potential in developing edible films, probiotics, nanoparticles, carbon dots, microbial media, biochar and biosorbents.

Surface Functionalization of Bioactive Glasses with Polyphenols from Padina pavonica Algae and In Situ Reduction of Silver Ions: Physico-Chemical Characterization and Biological Response

Bioactive glasses (BGs) are attractive materials for bone replacement due to their tailorable chemical composition that is able to promote bone healing and repair. Accordingly, many attempts have been introduced to further improve BGs’ biological behavior and to protect them from bacterial infection, which is nowadays the primary reason for implant failure. Polyphenols from natural products have been proposed as a novel source of antibacterial agents, whereas silver is a well-known antibacterial agent largely employed due to its broad-ranged activity. Based on these premises, the surface of a bioactive glass (CEL2) was functionalized with polyphenols extracted from the Egyptian algae Padina pavonica and enriched with silver nanoparticles (AgNPs) using an in situ reduction technique only using algae extract. We analyzed the composite’s morphological and physical-chemical characteristics using FE-SEM, EDS, XPS and Folin–Ciocalteau; all analyses confirmed that both algae polyphenols and AgNPs were successfully loaded together onto the CEL2 surface. Antibacterial analysis revealed that the presence of polyphenols and AgNPs significantly reduced the metabolic activity (>50%) of Staphylococcus aureus biofilm in comparison with bare CEL2 controls. Finally, we verified the composite’s cytocompatibility with human osteoblasts progenitors that were selected as representative cells for bone healing advancement.

Algae-based metallic nanoparticles: Synthesis, characterization and applications

Nanomaterials (NMs) tailored via conventional physicochemical routes play havoc with the environment that has led to the evolution of competent green routes for the actualization of a circular economy on an industrial-scale. Algae belonging to the class Cyanophyceae, Chlorophyceae, Phaeophyceae and Rhodophyceae have been harnessed as nano-machineries through intracellular and extracellular synthesis of gold (Au), silver (Ag) and several other metallic nanoparticles. Algae are an appealing platform for the production of diverse NMs, primarily due to the presence of bioactive compounds such as pigments and antioxidants in their cell extracts that act as biocompatible reductants. Chlorella spp. and Sargassum spp. have been extensively explored for the synthesis of nanoparticles having antimicrobial properties, which can potentially substitute conventional antibiotics. Characterization of nanoparticles (NPs) synthesised from algae has been done using advanced spectroscopic, diffractographic and microscopic techniques such as UV-Vis FT-IR, DLS, XPS, XRD, SEM, TEM, AFM, HR-TEM, and EDAX. The present paper reviews the information available on algae-mediated biosynthesis of various NPs, their characterization and applications in different domains.

Phycosynthesis and Enhanced Photocatalytic Activity of Zinc Oxide Nanoparticles Toward Organosulfur Pollutants

A novel eco-friendly procedure was developed to produce safer, stable and highly pure zinc oxide nanoparticles (ZnO NPs) using microalgae Chlorella extract. The ZnO NPs were synthesized simply using zinc nitrate and microalgae Chlorella extract which conducted at ambient conditions. In this recipe, microalgae Chlorella extract acted as the reducing agent and a stabilizing layer on fresh ZnO NPs. UV–visible spectrum was confirmed the formation of ZnO NPs showing an absorption peak at 362 nm. XRD results demonstrated that prepared ZnO NPs has a high-crystalline hexagonal (Wurtzite) structure, with average size about 19.44 nm in diameter. FT-IR spectral analysis indicated an active contribution of algae-derived biomolecules in zinc ions bioreduction. According to SEM and TEM observations, ZnO NPs are well dispersed and has a hexagonal shape with the average size of 20 ± 2.2 nm, respectively. Based on gas chromatography analyses, the optimum 0.01 g/L dosage of ZnO catalyst revealed an effective photocatalytic activity toward the degradation (97%) of Dibenzothiophene (DBT) contaminant as an organosulfur model in the neutral pH at the mild condition. Rapid separation and facile recyclability at five consecutive runs were demonstrated high efficiency and durability of green ZnO nanophotocatalyst. The possible mechanisms of green ZnO NPs formation and the photo-desulfurization of DBT were also proposed.