Green Plant Extract-Based Synthesis of Multifunctional Nanoparticles and their Biological Activities

 The emerging properties of noble metal nanoparticles (NPs) are attracting huge interest from the translational scientific community and have led to an unprecedented expansion of research and exploration of applications in biotechnology and biomedicine. An array of physical, chemical and biological methods has been used to synthesize nanomaterials. In order to synthesize noble metal NPs of particular shapes and sizes, specific methodologies have been formulated. Although ultraviolet irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques have been used successfully to produce NPs, they remain expensive and involve hazardous chemicals. Therefore, there is a growing concern about developing environment-friendly and sustainable methods. Since the synthesis of nanoparticles of different compositions, sizes, shapes and controlled dispersity is an important aspect of nanotechnology, new cost-effective procedures are being developed. Microbial synthesis of NPs is a green chemistry approach that interconnects nanotechnology and microbial biotechnology. Biosynthesis of gold, silver, gold–silver alloy, selenium, tellurium, platinum, palladium, silica, titania, zirconia, quantum dots, magnetite, and uraninite nanoparticles by bacteria, actinomycetes, fungi, yeasts, and viruses have been reported. However, despite stability, biological NPs are not monodispersed, and the rate of synthesis is slow. To overcome these problems, several factors, such as microbial cultivation methods and extraction techniques, have to be optimized, and the combinatorial approach, such as photobiological methods, may be used. Cellular, biochemical and molecular mechanisms that mediate the synthesis of biological NPs should be studied in detail to increase the rate of synthesis and improve the properties of NPs. 

A new class of diagnostic and therapeutic tools for various diseases has been made possible by advancements in polymeric nanoparticles as innovative nanomedicines. Although there are many benchtop studies in the nanoworld, their application to already marketed goods is still in its infancy. Problems with nanomedicine characterization cause this lack of transference, among other things. Three nanoscale characterization approaches may be distinguished: physicochemical property characterization, biological interactions of nanomaterials, and analytical characterization and purification procedures. Physical qualities may be assessed using a variety of methods in many situations. Choosing the best appropriate method is made more difficult by many advantages and disadvantages of each methodology; frequently, a combinatorial characterization approach is required. Scientists from many domains must find answers to the difficulties in reliable characterization of the nanomaterials after their fabrication and various systematic stages.

The new scientific innovation of engineering nanoparticles (NPs) at the atomic scale (diameter<100nm) has led to numerous novel and useful wide applications in electronics, chemicals, environmental protection, medical imaging, disease diagnoses, drug delivery, cancer treatment, gene therapy, etc. The manufacturers and consumers of nanoparticle-related industrial products, however, are likely to be exposed to these engineered nanomaterials, which have various physical and chemical properties at levels far beyond ambient concentrations. These nanosized particles are likely to increase unnecessary infinite toxicological effects on animals and the environment, although their toxicological effects associated with human exposure are still unknown. These ultrafine particles can enter the body through skin pores, debilitated tissues, injection, olfactory, respiratory, and intestinal tracts. These uptake routes of NPs may be intentional or unintentional. Their entry may lead to various diversified adverse biological effects. Until a clearer picture emerges, the limited data available suggest that caution must be exercised when potential exposures to NPs are encountered. Some methods have been used to determine the portal routes of nanoscale materials on experimental animals. They include pharyngeal instillation, injection, inhalation, cell culture lines and gavage exposures. 

Large surface area, small size, strong optical properties, controllable structural features, variety of bioconjugation chemistries, and biocompatibility make many different types of nanoparticles (NPs), such as gold NPs, useful for many biological applications, such as biosensing, cellular imaging, disease diagnostics, drug delivery, and therapeutics. Recently, interactions between proteins and NPs have been extensively studied to understand, control, and utilize the interactions involved in biomedical applications of NPs and several biological processes, such as protein aggregation, for many diseases, including Alzheimer's. These studies also offer fundamental knowledge on changes in protein structure, protein aggregation mechanisms, and ways to unravel the roles and fates of NPs within the human body.

Nanoparticles (NPs) have the potential to produce deleterious effects on organ, tissue, cellular, subcellular, and protein levels due to their peculiar physicochemical features. Metal NPs are gaining prominence and are being used in a variety of medicinal, consumer, industrial, and military applications. Furthermore, as particle size falls, some metal-based NPs become increasingly poisonous, despite the fact that the same substance is rather innocuous in its bulk form. NPs can also interact with proteins and enzymes within human cells, causing reactive oxygen species to be produced, an inflammatory response to be initiated, and mitochondrial disruption and destruction, ending in apoptosis or necrosis. As a result, deciding whether the advantages of NPs outweigh the hazards presents various challenges.

 Environmental deterioration is currently a major problem for both emerging and wealthy nations. Extensive industrialization and intensive agricultural activity are the main causes of land, water, and air contamination. There are numerous conventional treatments for various environmental contaminants, but each has drawbacks. As a result, a different approach is necessary, one that is efficient, less harmful, and produces better results. In terms of cleaning up the environment, nanomaterials have garnered much interest. Nanomaterials outperform more traditional methods for environmental remediation due to their enormous surface area and strong reactivity. For particular applications, they can be altered to include new functionalities. Nanoscale materials can be very reactive due to the high surface-areato-volume ratio and a greater number of reactive sites. These traits enable greater contaminant interaction, which prompts a rapid decrease in pollutant concentration. In order to remove toxins from diverse environmental media (e.g., soil, water, and air), environmental remediation primarily uses various methods.