A.K. Kumaraguru

Metallic silver nanoparticle: a therapeutic agent in combination with antifungal drug against human fungal pathogen.

Silver nanoparticles (Ag-NPs) are known to have inhibitory and fungicidal effects. Resistance against fungal infection has emerged as a major health problem in recent years, which needs great and immediate concern. Here, we report the extracellular biological synthesis of silver nanoparticles through a simple green route approach using a marine mangrove (Rhizophora mucronata) and silver nitrate. Aqueous extract of marine mangrove helped in reduction and was used as capping agent in biological synthesis. Nanoparticles were characterized using microscopy and spectroscopy techniques such as HRTEM, UV–Vis absorption spectroscopy and FTIR spectroscopy. X-ray diffraction analysis showed that the nanoparticles had face centered cubic structure with crystalline nature. FTIR spectroscopy showed the presence of different functional groups, such as hydroxyl and carbonyl, involved in the synthesis of nanoparticles. The antifungal activity of fluconazole and itraconazole was enhanced against the tested pathogenic fungi in the presence of Ag-NP and confirmed from increase in fold area of inhibition. This environmentally friendly method of biological synthesis can be easily integrated for various medical applications.

Drug Delivery System for Controlled Cancer Therapy Using Physico-Chemically Stabilized Bioconjugated Gold Nanoparticles Synthesized from Marine Macroalgae, Padina Gymnospora

Gold nanoparticles (AuNPs) have always been considered as superior tools for biosystem applications owing to their characteristic optical properties in form of surface plasmon resonance and amperometric properties with very low or no immediate toxicity. Biosystem application based tools have been designed based on many studies with gold nanoparticles but the reduction of bulk material to nanosized particle in conjugation with biomolecules in a physicochemical environment is an area requiring deeper investigation. In the present study complementary high resolution imaging techniques on different length scale are applied to elucidate morphology of gold nanoparticles. The biomolecules involved in conjugation and reduction were further characterized. The impact of macroalgae broth concentration on formation of AuNPs (8-21 nm) were further studied to determine the functional and molecular mechanism of cell death on Liver cancer (HepG2) cell line and Lung cancer (A549) cell line. We report AuNPs-induced death response in human carcinoma liver cell line HepG2 in contrast to lung cancer cell line which remained little affected. The induction specificity for death response in lung cells clarifies that AuNPs do not universally target all cell types. Altered DNA fragmentation and cell staining in different cancer cell suggests a potential for in vivo applications of gold nanomaterials and demands the need of the time for studies evaluating the interactions of nanomaterials with biomolecules and cellular components for controlled cancer therapy.

Cancerous cell targeting and destruction using pH stabilized amperometric bioconjugated gold nanoparticles from marine macroalgae, Padina gymnospora

Abstract The main aim of this study was, using biomechanistic approach, to synthesize and characterize amperometric stable gold nanoparticles (AuNPs) under different pH conditions using UV Spec, dynamic light scattering and TEM with energy dispersive X-ray analysis. The biomolecules involved in conjugation and reduction were further characterized by Fourier transform infrared analysis. The pH stabilized nanoparticles were studied to determine the functional and molecular mechanism of cell death on liver cancer (HepG2) cell line and gastric cancer (YCC3) cell line. The zeta potential and TEM imaging demonstrated that AuNPs were spherical in nature and can pass through the cellular membrane because of their intrinsic properties of AuNPs to bind to carbon-bonded sulfhydryl (–C–SH or R–SH) group and, therefore, could interact with intracellular components of the cell which was confirmed through phase contrast microscopy. Altered molecular mechanism and cellular effects in different cancer cell suggest a potential for in vivo applications of gold nanomaterials.

Rapid biomimetic synthesis of silver nanoparticles from asiatic mangrove (Rhizopora mucronata) and its antimicrobial activity against clinically isolated pathogens

In the present study, a facile and ecofriendly method has been developed for the synthesis of silver nanoparticles from silver nitrate using Asiatic mangrove (Rhizopora mucronata) a natural biopolymer, as a reducing and stabilizing agent. The Influence of different parameters such as pH, temperature and reaction time on the synthesis of nanoparticles was studied. The results recorded from UV-vis spectrum, scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) support the biosynthesis and characterization of silver nanoparticles. Biosynthesis of silver nanoparticles and activity on clinically isolated human pathogens viz., Gram positive and Gram negative bacteria and fungi were investigated. The synthesized silver nanoparticles had significant antibacterial action on both the classes of bacteria. As the silver nanoparticles are encapsulated with functional group rich mangrove, they can be easily integrated for various medical applications.

The cytotoxicity and cellular stress by temperature-fabricated polyshaped gold nanoparticles using marine macroalgae, Padina gymnospora

Bioreduction of metal ions for the synthesis of stable nanoparticles (NPs) in physiological environment has been a great challenge in the field of nanotechnology and its application. In the present study, well‐defined biofunctionalized gold nanoparticles (AuNPs) were developed following a biomimetic approach for an enhanced anticancer activity. The fucoxanthins‐capped crystalline AuNPs showed a particle size of 14 nm. The temperature‐mediated biosynthesized NPs were characterized by UV–vis, dynamic light scattering, high‐resolution transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. The cytotoxicity of the NPs was analyzed on liver (HepG2) and lung (A549) cancerous cells. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay infers that the biofunctionalized polyshaped AuNPs synthesized with an aqueous macroalgae extract showed a satisfactory anticancer effect on the cell lines, as evaluated by changes in cell morphology, cell viability, and metabolic activity. An altered cellular function and the morphology of cancer cell lines suggest a potential for in vivo application of AuNPs and the need to understand the interactions between nanomaterials, biomolecules, and cellular components. With continued improvements, these NPs may prove to be potential drug delivery vehicles for cancer therapy.