Marine Macroalgae Display Bioreductant Efficacy for Fabricating Metallic Nanoparticles: Intra/Extracellular Mechanism and Potential Biomedical Applications

Abstract

The application of hazardous chemicals during nanoparticle (NP) synthesis has raised alarming concerns pertaining to their biocompatibility and equally to the environmental harmlessness. In the recent decade, nanotechnological research has made a gigantic shift in order to include the natural resources to produce biogenic NPs. Within this approach, researchers have utilized marine resources such as macroalgae and microalgae, land plants, bacteria, fungi, yeast, actinomycetes, and viruses to synthesize NPs. Marine macroalgae (brown, red, and green) are rich in polysaccharides including alginates, fucose-containing sulfated polysaccharides (FCSPs), galactans, agars or carrageenans, semicrystalline cellulose, ulvans, and hemicelluloses. Phytochemicals are abundant in phenols, tannins, alkaloids, terpenoids, and vitamins. However, microorganisms have an abundance of active compounds ranging from sugar molecules, enzymes, canonical membrane proteins, reductase enzymes (NADH and NADPH), membrane proteins to many more. The prime reason for using the aforesaid entities in the metallic NPs synthesis is based on their intrinsic properties to act as bioreductants, having the capability to reduce and cap the metal ions into stabilized NPs. Several green NPs have been verified for their biocompatibility in human cells. Bioactive constituents from the above resources have been found on the green metallic NPs, which has demonstrated their efficacies as prospective antibiotics and anti-cancer agents against a range of human pathogens and cancer cells. Moreover, these NPs can be characterized for the size, shapes, functional groups, surface properties, porosity, hydrodynamic stability, and surface charge using different characterization techniques. The novelty and originality of this review is that we provide recent research compilations on green synthesis of NPs by marine macroalgae and other biological sources (plant, bacteria, fungi, actinomycetes, yeast, and virus). Besides, we elaborated on the detailed intra- and extracellular mechanisms of NPs synthesis by marine macroalgae. The application of green NPs as anti-bacterial, anti-cancer, and popular methods of NPs characterization techniques has also been critically reviewed.

Microalgae as a potential natural source for the green synthesis of nanoparticles

“…32 Macroalgae, referred to as seaweeds, are multicellular, structurally complex and can be counted with the naked eye (sizes of up to 60 m in length), while a microscope is needed to observe microalgae (measuring about 3-20 mm), which are single-celled (unicellular) or form single colonies and may be prokaryotic or eukaryotic types. 33,34 Although both algae can be harvested several times in the same year, microalgae are easy to handle and cultivate, grow fast, and are rich sources of nutrients, biomolecules, and bioactive compounds. 34 Live and dead dry microalgae-based biomass may be used for the biosynthesis of NPs.…”

“…Thus, -NH 2 groups play a protective role by coating the NPs, providing stabilization, and preventing agglomeration in intracellular and extracellular processes. 33,48,49 Using Fourier transform infrared spectroscopy (FTIR), Arya A. et al (2020) 50 compared and identified the main functional groups present in an algal extract from B. braunii that could reduce and stabilize palladium and platinum NPs, and revealed the role of protein amides as a capping agent. As another example, Mahajan A. et al (2019) 51 demonstrated the ability of the aqueous extract of C. vulgaris to reduce silver ions in AgNPs, which was also accompanied by its subsequent stabilization.…”

Metal Ions in Cancer Prevention and Treatment with Traditional Chinese Medicine

“…Despite the excellent antibacterial and anti-cancer efficacy of green-synthesized Ag and AuNPs, the mechanism regarding algal metal NPs remains unclear. Furthermore, extensive studies must be conducted to determine the role of specific biomolecules in the production of metal NPs mediated by algae [100] .…”

Marine-Bioinspired Nanoparticles as Potential Drugs for Multiple Biological Roles

“…Nanoparticles have a wide range of applications, including the medicinal, diagnostic, drug discovery, biological sensor, and reagent industries [ 28 ]. These biologically active nanoparticles are produced by employing various biological fluids as reducing agents for metal and non-metal ions, such as gold, silver, copper, zinc oxide, platinum, and titanium oxide [ 29 ]. The diverse therapeutic applications of nanoparticles, as well as the outbreak of several infectious diseases, motivate this research [ 30 ].…”

“…Fungi, bacteria, plants, and algae from the marine have been found to produce nanoparticles [ 12 ]. Green synthetic nanoparticles can be easily decomposed using enzymes included in the nanoparticles, making them more environmentally benign than conventional agents [ 29 ]. The reduction of metal ions by reducing agents found in the organism is essential for the synthesis of metal nanoparticles [ 32 ].…”