<p>Recent Developments in the Facile Bio-Synthesis of Gold Nanoparticles (AuNPs) and Their Biomedical Applications</p>

Abstract

Gold nanoparticles (AuNPs) are extensively studied nanoparticles (NPs) and are known to have profound applications in medicine. There are various methods to synthesize AuNPs which are generally categorized into two main types: chemical and physical synthesis. Continuous efforts have been devoted to search for other more environmental-friendly and economical large-scale methods, such as environmentally friendly biological methods known as green synthesis. Green synthesis is especially important to minimize the harmful chemical and toxic by-products during the conventional synthesis of AuNPs. Green materials such as plants, fungi, microorganisms, enzymes and biopolymers are currently used to synthesize various NPs. Biosynthesized AuNPs are generally safer for use in biomedical applications since they come from natural materials themselves. Multiple surface functionalities of AuNPs allow them to be more robust and flexible when combined with different biological assemblies or modifications for enhanced applications. This review focuses on recent developments of green synthesized AuNPs and discusses their numerous biomedical applications. Sources of green materials with successful examples and other key parameters that determine the functionalities of AuNPs are also discussed in this review.

Hesperidin Loaded on Gold Nanoparticles as a Drug Delivery System for a Successful Biocompatible, Anti-Cancer, Anti-Inflammatory and Phagocytosis Inducer Model

“…Thus, the results show that Hsp-AuNPs were able to particularly stimulate the delivery of hesperidin to cancer cells 29 . Previous studies also reported rapid release of chemotherapeutic drug loaded on AuNPs in acidic conditions when compared to neutral conditions 30,31 .…”

Epigallocatechin-3-Gallate-Loaded Gold Nanoparticles: Preparation and Evaluation of Anticancer Efficacy in Ehrlich Tumor-Bearing Mice

“…A green synthesis approach was used for the preparation of EGCG-loaded GNPs where HAuCl 4 was reduced in aqueous solution using EGCG. This approach is eco-friendly, clean, simple, efficient, and avoids the use of hazardous man-made chemicals [25,32]. EGCG has eight orthophenolic hydroxyl groups, which form complexes with Au 3+ ions and facilitate their reduction to gold ions to form EGCG-capped GNPs [25].…”

“…The GNPs were synthesized using a "green" methodology which ensures effective use of EGCG where it serves a triple purpose; the main therapeutic agent, a reducing agent for gold chloride and a stabilizing agent for the formed GNPs. Further, this methodology avoids the use of man-made chemicals as reducing agents, which is environment-friendly, easy to scale up, and limits potentially toxic byproducts produced during GNPs synthesis [32]. EGCG-loaded GNPs were characterized for particle size and morphology, polydispersity index, drug encapsulation efficiency and drug loading capacity.…”

Recent advances in the antilung cancer activity of biosynthesized gold nanoparticles

“…Several physical, chemical, and biological methods for the synthesis and assembly of Au‐NPs have already been reported. Among these methods, the biological method, also called green or eco‐friendly synthesis, is eco‐benign, clean, less toxic, and more cost‐effective compared with other synthesis methods (Khan, Ullah, Khan, Mashwani, & Nadhman, 2019; Lee et al, 2020; Lopes, Alves, Pereira, Granjeiro, & Leite, 2019; Siddiqi & Husen, 2017). Previous studies have reported on the biological synthesis of Au‐NPs using microorganisms (bacteria, fungi, and yeasts; Narayanan & Sakthivel, 2010; Pei et al, 2017; Tripathi, Shrivastav, & Shrivastav, 2018) and natural plants ( Salix alba leaves, Sambucus nigra fruit extract, Mentha piperita leaf extracts, flower petals of Moringa oleifera , root extracts of Glycyrrhiza uralensis , Garcinia mangostana fruit peel, Panax ginseng fresh leaves, Magnolia officinalis , and Rabdosia rubescens , etc.…”