The green synthesis of nanoparticles (NPs) using living cells is a promising and novelty tool in bionanotechnology. Chemical and physical methods are used to synthesize NPs; however, biological methods are preferred due to its eco-friendly, clean, safe, cost-effective, easy, and effective sources for high productivity and purity. High pressure or temperature is not required for the green synthesis of NPs, and the use of toxic and hazardous substances and the addition of external reducing, stabilizing, or capping agents are avoided. Intra- or extracellular biosynthesis of NPs can be achieved by numerous biological entities including bacteria, fungi, yeast, algae, actinomycetes, and plant extracts. Recently, numerous methods are used to increase the productivity of nanoparticles with variable size, shape, and stability. The different mechanical, optical, magnetic, and chemical properties of NPs have been related to their shape, size, surface charge, and surface area. Detection and characterization of biosynthesized NPs are conducted using different techniques such as UV-vis spectroscopy, FT-IR, TEM, SEM, AFM, DLS, XRD, zeta potential analyses, etc. NPs synthesized by the green approach can be incorporated into different biotechnological fields as antimicrobial, antitumor, and antioxidant agents; as a control for phytopathogens; and as bioremediative factors, and they are also used in the food and textile industries, in smart agriculture, and in wastewater treatment. This review will address biological entities that can be used for the green synthesis of NPs and their prospects for biotechnological applications.

Green Synthesis of Metallic Nanoparticles and Their Prospective Biotechnological Applications: an Overview

Gold nanoparticles (GNPs) have generated keen interest among researchers in recent years due to their excellent physicochemical properties. In general, GNPs are biocompatible, amenable to desired functionalization, non-corroding, and exhibit size and shape dependent optical and electronic properties. These excellent properties of GNPs exhibit their tremendous potential for use in diverse biomedical applications. Herein, we have evaluated the recent advancements of GNPs to highlight their exceptional potential in the biomedical field. Special focus has been given to emerging biomedical applications including bio-imaging, site specific drug/gene delivery, nano-sensing, diagnostics, photon induced therapeutics, and theranostics. We have also elaborated on the basics, presented a historical preview, and discussed the synthesis strategies, functionalization methods, stabilization techniques, and key properties of GNPs. Lastly, we have concluded this article with key findings and unaddressed challenges. Overall, this review is a complete package to understand the importance and achievements of GNPs in the biomedical field.

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Role of gold nanoparticles in advanced biomedical applications

Chitosan is mainly derived from seafood by-products and the thereof chitosan nanoparticles (CNPs) are known as nontoxic, biocompatible, biodegradable and functionalized nanostructures. CNPs, as green fillers, showed an appropriate potential in reinforcement of various biodegradable composites for food packaging and biomedical applications. After evaluation of different fabrication approaches and characterization techniques of CNPs, the changes in physical, mechanical, thermal, structural, morphological, and antimicrobial attributes of nanobiocomposites as a result of CNPs addition are discussed. The influence of bioactive loaded-CNPs and hybrid CNPs with metal nanoparticles, graphene, and montmorillonite in nanocomposites is also presented. Finally, the safety aspects of CNPs-loaded structures are highlighted to evaluate their implementation in food packaging and biomedical systems. It can be concluded that regardless of a few drawbacks, CNPs are promising nanomaterials to improve various operational, structural and antimicrobial properties of biocomposites for various applications in food packaging, delivery systems and biomedical uses.

A comprehensive review on the nanocomposites loaded with chitosan nanoparticles for food packaging.

Chitosan is a cationic natural polysaccharide, which has emerged as an increasingly interesting biomaterialover the past few years. It constitutes a novel perspective in drug delivery systems and nanocarriers' formulations due to its beneficial properties, including biocompatibility, biodegradability and low toxicity. The potentiality of chemical or enzymatic modifications of the biopolymer, as well as its complementary use with other polymers, further attract the scientific community, offering improved and combined properties in the final materials. As a result, chitosan has been extensively used as a matrix for the encapsulation of several valuable compounds. In this review article, the advantageous character of chitosan as a matrix for nanosystemsis presented, focusing on the encapsulation of natural products. A five-year literature review is attempted covering the use of chitosan and modified chitosan as matrices and coatings for the encapsulation of natural extracts, essential oils or pure naturally occurring bioactive compounds are discussed.

https://www.mdpi.com/1999-4923/12/7/669/pdf

Nanosystems for the Encapsulation of Natural Products: The Case of Chitosan Biopolymer as a Matrix

Inorganic/organic hybrid nanosystems have been increasingly developed for their versatility and efficacy at overcoming obstacles not readily surmounted by nonhybridized counterparts. Currently, hybrid nanosystems are implemented for gene therapy, drug delivery, and phototherapy in addition to tissue regeneration, vaccines, antibacterials, biomolecule detection, imaging probes, and theranostics. Though diverse, these nanosystems can be classified according to foundational inorganic/organic components, accessory moieties, and architecture of hybridization. Within this Review, we begin by providing a historical context for the development of biomedical hybrid nanosystems before describing the properties, synthesis, and characterization of their component building blocks. Afterward, we introduce the architectures of hybridization and highlight recent biomedical nanosystem developments by area of application, emphasizing hybrids of distinctive utility and innovation. Finally, we draw attention to ongoing clinical trials before recapping our discussion of hybrid nanosystems and providing a perspective on the future of the field.

Hybrid Nanosystems for Biomedical Applications.

Preparation and characterization of hybrid chitosan-silver nanoparticles (Chi-Ag NPs); A potential antibacterial agent.

In this present research, the Gold nanoparticles (GA-AuNPs) produced from Gelidiella acerosa, marine algae using green synthesis method was evaluated for its antidiabetic, antibacterial and antioxidant activity. Well-developed GA-AuNPs were effectively characterized using advanced analytical instruments like HRTEM, UV–visible, SEM and XRD. This analysis exposed GA-AuNPs to be present with spherical, hexagonal structure and crystalline nature. The average size of GA-AuNPs particles was estimated to lie between 5.81 nm to 117.59 nm by using Debye–Scherer equation. The enzyme inhibitory property of (IC50) of G. acerosa aqueous extract and synthesized gold nanoparticles from G. acerosa against α amylase and α- glucosidase enzyme was found to be 2.1 ± 0.01, 3.7 ± 0.01 µg/mL and 2.8 ± 0.02, 4.1 ± 0.01, respectively. Further antioxidant assessment of GA-AuNPs were examined using DPPH and FRAP assays, the results exhibited that the strong antioxidant activity were observed in all the concentrations when compared with standard. Finally antibacterial activity was evaluated the GA-AuNPs against gram positive and gram negative bacteria, the strong antibacterial activity was observed in both the bacterial strains when compared with standard antibiotic. The GA-AuNPs from marine algae was exhibited to be strong inhibitory activity against alpha amylase and alpha glucosidase enzyme, antioxidant activity and antibacterial activity, these GA-AuNPs are projected to have potential biological applications.

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Facile green synthesis of gold nanoparticles from marine algae Gelidiella acerosa and evaluation of its biological Potential

Enhalus acoroides (Linnaeus f.) Royle belongs to the Family: Hydrocharitaceae is an abundantly growing seagrass in coastal areas of Gulf of Mannar. Sea grasses contain very good potent therapeutic properties for challenging diseases. The current investigation is to green synthesis Ag-NPs from Enhalus acoroides and characterize silver nanoparticles (Ag-NPs) and evaluated α-glucosidase inhibition activity. Furthermore, the characterization of the same using ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray (EDX), and followed by Transmission Electron Microscopy (TEM). Surface Plasmon resonance exhibited the development of Ag-NPs in UV–Visible spectra at 419 nm. The FTIR examination was done to find and read the moiety accountable aimed at the bioconversion of silver ions. The crystalline form was observed in the XRD examination. The synthesized Ag-NPs were polydispersed spherical Ag-NPs as confirmed by EDAX and stabilized in the solution with the spherical shapes further confirmed by TEM analysis designate in the reading of 2–100 nm. The findings of the study shown that Ag-NPs of promisingly proved have strong α-glucosidase inhibitory activity by which Ag-NPs with an IC50 47 µg/ml. This current research report is first to account on the green synthesis of silver nanoparticles from seagrass E. acoroides, because there is no literature survey and investigations on Enhalus acoroides. Hence, we suggest that Ag-NPs synthesized from E. acoroides might be a significant resource of α-glucosidase inhibitors preparation that may benefit diabetes treatment.

https://link.springer.com/content/pdf/10.1007%2Fs40097-016-0200-7.pdf

B. Sudhagar

Papers

Preparation and characterization of hybrid chitosan-silver nanoparticles (Chi-Ag NPs); A potential antibacterial agent.

Facile green synthesis of gold nanoparticles from marine algae Gelidiella acerosa and evaluation of its biological Potential

Seagrass-mediated silver nanoparticles synthesis by Enhalus acoroides and its α-glucosidase inhibitory activity from the Gulf of Mannar

Hydrothermal assisted Eichhornia crassipes mediated synthesis of magnetite nanoparticles (E-Fe3O4) and its antibiofilm activity