Biosynthesis of zerovalent iron nanoparticles for catalytic reduction of 4-nitrophenol and decoloration of textile dyes

Recent development on nanomaterial-based biosensors for identifying thyroid tumor biomarkers

The incidence of thyroid tumors has been increasing yearly over the past decade, making it the fourth highest tumor in women. This places various biological burdens on those affected. Currently, thyroid tumors are primarily diagnosed using percutaneous fine needle aspiration and ultrasound. However, these methods are complex, expensive, and less accurate, and they may fail to detect some thyroid nodules. As an alternative, researchers are focusing on blood-based biomarkers in addition to the traditional diagnostic methods, assisted predominantly by nanomaterials. Early identification of thyroid cancer is crucial as it is highly treatable. Various sensing systems have been developed using nanomaterial-mediated approaches to enhance the detection system. Nanomaterials are effectively applied in biosensors for surface functionalization and are conjugated with biomolecules to improve the interaction with the target analyte. This review discusses nanomaterial-assisted thyroid tumor detection, with a special focus on nanomaterial-based biosensors.

Zero-valent Iron Nanoparticles: Biogenic Synthesis and their Medical Applications; Existing Challenges and Future Prospects

OBJECTIVES

In the last decade, nanobiotechnology is emerging as a keen prudence area owing to its widespread applications in the medical field. In this context, zero-valent iron nanoparticles (nZVI) have garnered tremendous attention attributed to their cheap, non-toxic, excellent paramagnetic nature, extremely reactive surface, and dual oxidation state that makes them excellent antioxidants and free-radical scavengers. Facile biogenic synthesis, in which a biological source is used as a template for the synthesis of NPs, is presumably dominant among other physical and chemical synthetic procedures. The purpose of this review is to elucidate plant-mediated synthesis of nZVI, although they have been successfully fabricated by microbes and other biological entities (such as starch, chitosan, alginate, cashew nut shell, etc.) as well.

METHODS

The methodology of the study involved keyword searches of electronic databases, including ScienceDirect, NCBI, and Google Scholar (2008-2023). Search terms of the review included 'biogenic synthesis of nZVI', 'plant-mediated synthesis of nZVI', 'medical applications of nZVI', and 'Recent advancements and future prospects of nZVI'.

RESULTS

Various articles were identified and reviewed for biogenic fabrication of stable nZVI with the vast majority of studies reporting positive findings. The resultant nanomaterial found great interest for biomedical purposes such as their use as biocompatible anticancer, antimicrobial, antioxidant, and albumin binding agents that have not been adequately accessed in previous studies.

CONCLUSION

This review shows that there are potential cost savings applications to be made when using biogenic nZVI for medical purposes. However, the encountering challenges concluded later, along with the prospects for sustainable future development.

Study on Biogenic Spindle-Shaped Iron-Oxide Nanoparticles by Pseudostaurosira trainorii in Field of Laser Desorption/Ionization Applications

Nanostructures-assisted laser desorption/ionization mass spectrometry (NALDI-MS) is gaining attention for the analysis of a wide range of molecules. In this present investigation, Pseudostaurosira trainorii mediated biosynthesized iron-oxide nanoparticles (IONPs) have been utilized as nanostructures assisting ionization and desorption for laser desorption/ionization mass spectrometry (LDI-MS). The chain forming diatom, P. trainorii showed efficiency in the production of IONPs against 0.01 M Fe+3 (pH 2) aqueous solution at the intracellular and extracellular level. The whole biomass and external media turned dark orange in color after 3 days of reaction with Fe3+ solution. Scanning electron microscopic (SEM) images illustrated that the surface of Fe3+ exposed frustules of P. trainorii were entirely covered by synthesized nanostructures contrasting with the natural surface ornamentation of control cells. The IONPs loaded frustules also exhibited catalytic properties by decolorizing yellow colored nitrophenol after 3 h of reaction. Transmission electron microscopic (TEM) images confirmed that the produced particles are spindle-shaped with ~50–70 nm length and ~10–30 nm width. The biogenic IONPs were utilized as an inorganic matrix in LDI-MS and showed high sensitivity towards small molecules as glucose, alanine and triacylglycerols at nano- and picomolar level per spot, respectively. The presented biocompatible technique offers new perspectives in nanobiotechnology for the production of spindle-shaped IONPs that can be applied in future for the preparation of NALDI plates.