Progress in Laser Ablation and Biological Synthesis Processes: “Top-Down” and “Bottom-Up” Approaches for the Green Synthesis of Au/Ag Nanoparticles

Abstract

Because of their small size and large specific surface area, nanoparticles (NPs) have special properties that are different from bulk materials. In particular, Au/Ag NPs have been intensively studied for a long time, especially for biomedical applications. Thereafter, they played a significant role in the fields of biology, medical testing, optical imaging, energy and catalysis, MRI contrast agents, tumor diagnosis and treatment, environmental protection, and so on. When synthesizing Au/Ag NPs, the laser ablation and biosynthesis methods are very promising green processes. Therefore, this review focuses on the progress in the laser ablation and biological synthesis processes for Au/Ag NP generation, especially in their fabrication fundamentals and potential applications. First, the fundamentals of the laser ablation method are critically reviewed, including the laser ablation mechanism for Au/Ag NPs and the controlling of their size and shape during fabrication using laser ablation. Second, the fundamentals of the biological method are comprehensively discussed, involving the synthesis principle and the process of controlling the size and shape and preparing Au/Ag NPs using biological methods. Third, the applications in biology, tumor diagnosis and treatment, and other fields are reviewed to demonstrate the potential value of Au/Ag NPs. Finally, a discussion surrounding three aspects (similarity, individuality, and complementarity) of the two green synthesis processes is presented, and the necessary outlook, including the current limitations and challenges, is suggested, which provides a reference for the low-cost and sustainable production of Au/Ag NPs in the future.

In Vivo Biosynthesis of Au and Ag NPs Using Two Medicago sativa L. Genotypes

“…As the demand for NPs increases, they are being synthesised in larger quantities [2]. Physical and chemical methods make NP synthesis faster and more easily performed on a large scale but often involve the use of chemical solvents that can further increase the toxicity of NPs [7]. Currently, one of the biggest challenges and urgent goals is to find a method of NP synthesis that is as efficient as possible but healthier for the environment and people [11,12].…”

“…The physical approach is a top-down method in which NPs are made by mechanical breakdown [6]. The most popular methods for physical synthesis of Ag or Au NPs include laser ablation, ultrasonic machining, and ball milling [7]. The chemical approach is a bottom-up method in which NPs are made using a nucleation process with water-soluble cations as a precursor that triggers their reduction to metal monomers.…”

Exploring synthesis and applications of green nanoparticles and the role of nanotechnology in wastewater treatment

“…Adaptation of several practical methods to produce nanoparticles by varying their shapes, sizes, and chemical composition has been an attractive area of research [42] . The results of various multidimensional 1-D, 2-D, and 3-D meso‑structures is also caused by the interaction of nanoparticles with organic molecules, which stimulates shared behavior and sparks inquiries.…”

The impact of silver nanoparticles on the growth of plants: The agriculture applications

“…With the development of science, researchers have focused on the need of developing efficient techniques that synthesized environmentally friendly and non-toxic biocompatible nanoparticles [ 35 ]. Plants harbor several bioactive chemicals such as Flavonoids, aldehydes, phenols, amino-acids, vitamins and ketones, that are present in plants, which can reduce valuable metal ions [ 36 ]. Plant-mediated synthesis is recognized as a less costly, environmentally-friendly, and easily up-scalable method of synthesizing nanoparticles.…”