[Ethiopia] UV-vis, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, dynamic light scattering have all been used to investigate metal oxide nanoparticles generated by algae.
Algae are wont to turn even the most prestigious of swimming pools cloudy and green but given that they contain, in common with most living things, pigments, proteins, carbohydrates, fats, nucleic acids and secondary metabolites such as alkaloids, aromatic compounds, macrolides, peptides and terpenes, this is perhaps no surprise. What may be more surprising is that members of this diverse group of organisms can act as reducing agents for metal ions in their aqueous surroundings and produce metal oxide nanoparticles. As such they could be the perfect bioengineers for making uniform nanoparticles with antimicrobial activity against gram positive and gram negative pathogenic bacteria. Critical to the successful use of these algal bioengineers might be one additional characteristic: they undertake this role without generating toxic by-products.
There have been countless methods developed to make different types of nanoparticle, some scalable, some otherwise. Some that generate almost entirely random morphologies and shapes and sizes, others that produce greater uniformity. Many that are complicated and costly others less expensive but less efficient. Some researchers have turned to other bioengineers in the form of bacteria, fungi, and viruses to assist and various proteins, amines, amino acids, phenols, sugars, ketones, and aldehydes as auxiliaries for the formation of nanoparticles. All with as many countless degrees of success. Algal species includingBifurcaria bifurcate, Chlamydomonas reinhardtii, Chlorella vulgaris, Ecklonia cava, Fucus vesiculosus, Oscillatoria willei, Pithophora oedogonia, Sargassum muticum, Sargassum wightii, Spirulina platensis, Stoechospermum marginatum have been investigated.
Algae have also been used in the same context, but it is their range of biomolecules that might make them particularly useful in guiding the formation of nanoparticles, cell wall enzymes and various functional groups with reducing qualities under ambient conditions. Writing in the journal Nanoscale Research Letters Khwaja Salahuddin Siddiqi and Azamal Husen of the Department of Biology, at the University of Gondar in Ethiopia, review the state of the art when it comes to algal production of nanoparticles. “Algae are considered as significant nanofactories and hold a huge potential as ecofriendly and cost-effective tools, avoiding toxic, harsh chemicals and the high energy demand required for physiochemical fabrication,” the pair report. They also point out that the various algal biomolecules have a dual role in reducing metal ions to lead to nanoparticle formation but also act as capping agents for the final “product”.
Siddiqi and Husen also point out just how great the potential of these metal and metal oxide nanoparticles formed and functionalised by algae could be used in the treatment of infectious diseases caused by bacteria and fungi, they might also be used in phytomining and sequestering metals from waste products. There are many other potential applications.
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