A Deep Dive into the Green Synthesis of Nanoparticles

A Deep Dive into the Green Synthesis of Nanoparticles

Introduction

Nanotechnology offers revolutionary tools for medicine and science, but traditional methods for creating these tiny particles often involve harsh, toxic chemicals. This research excerpt explores a groundbreaking alternative: the green synthesis of nanoparticles. It details how scientists are harnessing the natural power of medicinal plant extracts to forge gold and silver nanoparticles in a way that is simple, cost-effective, and environmentally friendly. Dive in to understand the science behind this innovative process and its immense potential for the future of medicine and technology.

Original Excerpt: The Science of Green Synthesis

An Introduction to Nanotechnology

Nanotechnology is the science of manipulation, creation, and utilization of novel materials at the nano-scale, including nanoparticles (NPs). During the last few decades, nanoparticles have intrigued the attention of researchers from different disciplines. NPs can generally be defined as particulate materials with at least one dimension of less than 100 nanometers (nm). This growing interdisciplinary field connects the chemical, physical, engineering, and biological sciences.

Different types of nanomaterials—like selenium, tellurium, silver, gold, zinc, and copper—have been used to make nanoparticles from many plants and their extracts. Owing to their smaller particle size and increased surface area, NPs exhibit properties exceptionally different from the parent materials and serve as interesting candidates in numerous applications, including biomedical science, especially in pharmaceutical and biological applications.

Why is the Green Synthesis of Nanoparticles Necessary?

Bottom-up and top-down are commonly used approaches for NP synthesis. Different protocols have been established to synthesize NPs by chemical, physical, and biological methods. However, the maintenance of high pressure, temperature, and energy is a limiting factor during NP synthesis by physical methods. In chemical methods, the involvement of potentially hazardous and toxic compounds as solvents, starting materials, and reactants—along with the generation of toxic by-products—poses a risk not only to biological systems but also to the environment.

This has led to an increasing demand to develop a sustainable and environmentally friendly process for the green synthesis of nanoparticles without using harsh and toxic chemicals. To achieve such an objective, the exploitation of biological natural resources is a promising approach. This biosynthetic approach that utilizes plants or plant extracts for NP fabrication is a single-step technique that has emerged as a viable, simple, and efficient alternative process because of its economical, eco-friendly, and rapid nature.

The Role of Plants in the Green Synthesis of Nanoparticles

Medicinal plants are an ample bio-resource of compounds for modern medicines, pharmaceutical intermediates, and chemical compounds for synthetic drugs. These plants synthesize a variety of compounds with important and diverse biological properties. Using these natural compounds for the green synthesis of nanoparticles is a key application for human health.

Medicinal herbs produce various metabolites and are thus considered a chemical factory. These chemical compounds, specifically plant secondary metabolites, are responsible for the medicinal effects of plants. This includes glycosides, resins, saponins, and alkaloids. These therapeutic actions are attributed to plant pigments and secondary metabolites which can be refined to synthesize plant-based drugs.

The Process: A Case Study in the Green Synthesis of Nanoparticles

How Plant Extracts Enable the Green Synthesis of Gold Nanoparticles (AuNPs)

Bioinspired gold nanoparticles (AuNPs) were synthesized using methanolic crude extract solutions of different parts of A. jacquemontii, H. nepalensis, and V. jatamansi to reduce a 0.1mM Gold Chloride (AuCl₃) solution. The preliminary observation of the green synthesis of nanoparticles was carried out by visual monitoring and confirmation of a color change. When the plant extract was treated with the AuCl₃ solution, upon shaking, the color of the resulting solution changed from very light yellow to pink and then dark purple later on.

This color change was so obvious that it could be seen through the naked eye. The appearance of purple color represented the formation of AuNPs. During the experiment, it was generally observed that an increase in the ratio of the AuCl₃ solution and plant extract resulted in a denser solution, thus boosting the color intensity and referring to the formation of larger amounts of AuNPs.

Confirmation and Characterization in the Green Synthesis of Nanoparticles

The green synthesis of nanoparticles was further confirmed by UV-vis Spectrophotometric analysis. Free electrons present in AuNPs produce Surface Plasmon Resonance (SPR). The vibrations of free electrons of AuNPs with a light wave create a resonance resulting in the absorption of light. A UV-Vis spectrophotometer detects this absorption and gives an AuNPs characteristic peak in the 500nm-600nm range, with intensity depending upon the concentration of AuNPs.

Characterization of AuNPs was carried out by XRD, FTIR, and SEM analysis. XRD analysis was used to determine the nanocrystallite size and crystalline nature of the nanoparticles. FTIR analysis investigated the possible functional groups involved in the reduction of the gold. Further SEM analysis reported the size and shape of the synthesized nanoparticles. The stability of the AuNPs was evaluated at different temperatures and salt concentrations.

This eco-friendly process demonstrates a viable alternative to chemical methods. The data regarding the antioxidant activity of Gold nanoparticles (AuNPs) synthesized from methanolic crude extracts revealed that the AuNPs showed activity at all the tested concentrations. Generally, an increase in AuNPs concentration yielded higher activity, while decreased AuNPs concentration reported decreased antioxidant activity. Comparatively, among all the extracts of all the test plant species, n-butanol and ethyl acetate extract showed better antioxidant activity.

Conclusion

The green synthesis of nanoparticles represents a vital and innovative shift in the field of nanotechnology. By leveraging the inherent biochemical properties of medicinal plants, researchers can create functional gold and silver nanoparticles without the environmental and health risks associated with conventional chemical methods. As this thesis excerpt demonstrates, this plant-mediated approach is not only effective but also opens the door to developing new, sustainable technologies for medicine and beyond.

Source Citation

• Researcher: Madiha Iqbal
• Thesis Title: BIOGENIC SYNTHESIS, CHARACTERIZATION AND PHARMACOLOGICAL EVALUATION OF NANO-PARTICLES PREPARED BY USING THE EXTRACTS OF Arisaema jacquemontii, Hedera nepalensis AND Valeriana jatamansi
• Guide: Prof. Dr. Jehan Bakht (Chairman, Supervisory Committee)
• University: The University of Agriculture, Peshawar, Pakistan
• Completion Date: August, 2017
• Excerpt Source Pages: 1-4, 174-175, 181-182.

Disclaimer

Disclaimer: Some sentences have been lightly edited for SEO and readability. For the complete and original research, please refer to the full thesis PDF above.

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