Speakers - 2024

Biography

Dr. Farhat Afrin received her Ph.D. from Jadavpur University in India and pursued postdoctoral research at NIAID, NIH, USA, and the University of York, UK. She has also served the Department of Biotechnology, Hamdard University, New Delhi and the Department of Medical Laboratory Technology, Taibah University, Saudi Arabia.

Dr. Afrin is a recipient of several honors, including the American Association of Immunologists Young Faculty Travel Grant, the Commonwealth Academic Staff Fellowship, the International Association of Advanced Materials Scientist Award, the Department of Biotechnology Overseas Associateship, the Indian Council of Medical Research International fellowship, besides several research grants-in-aid. Her research interests are immunotherapeutics, epigenetics, herbal and nano-medicines for leishmaniasis, cancer, and diabetes. She has published over 62 papers in International journals with a cumulative impact factor of 229, an H index of 33, and a citation record of 2588 as per the Scopus database. And is an Associate Editor of several Journals and books. 

Abstract

The current therapeutic armory for visceral leishmaniasis (VL) caused by Leishmania donovani complex is inadequate, coupled with severe limitations and complications of post-kala-azar dermal leishmaniasis, HIV-coinfections and spread to non-endemic zones. Since the parasites reside mainly in phagolysosomal vacuoles within the macrophages, monotherapy using present antiparasitics is difficult. Combination therapy has proved ineffective due to mounting resistance. Searching for safe and effective drugs is desirable in the absence of any vaccine. There is a surge of interest in the application of nanoparticles for the therapeutic effectiveness of leishmaniasis. Aimed in this direction, we assessed the antileishmanial effect of gold nanoparticles (GNPs) against L. donovani. GNPs were synthesized by microwave-assisted heating and characterized for particle size by dynamic light scattering, atomic force microscopy (AFM), and optical properties by UV-visible spectroscopy. The MTT proliferation assay measured the cytotoxicity of GNPs. The antileishmanial activity of the nanoparticles was evaluated against L. donovani promastigotes in vitro and macrophage-infected amastigotes ex vivo. GNPs showed a strong surface plasmon resonance (SPR) peak at 520 nm and mean particle size, polydispersity index (PDI), and zeta potential of 56.0 ± 10 nm, 0.3 ± 0.1 and −27.0 ± 3 mV, respectively. The GNPs were smooth and spherical with a mean particle diameter of 20 ± 5 nm. Nanoparticles [1.2–100 μM] did not reveal cytotoxicity on RAW 264.7 murine macrophage cell line but showed pronounced antileishmanial activity with deformed morphology of L. donovani promastigotes. Growth reversibility analysis showed the least number of surviving parasites. GNPs exerted significant dose- and time-dependent activity against both the promastigote and amastigote stages of L. donovani with 50% inhibitory concentration (IC₅₀) of 18.4 ± 0.4 μM and 5.0 ± 0.3 μM, respectively. The enhanced activity of GNPs towards amastigotes compared to promastigotes may be due to more interaction of GNPs with the cell surface receptors of amastigotes. It was also observed that macrophages exposed to GNPs did not generate nitric oxide, the major microbicidal molecule. The reactive oxygen species (ROS)-independent antileishmanial activity of GNPs may have been mediated via parasite membrane disruption and/or apoptosis, which needs to be explored. GNPs may provide a platform to conjugate antileishmanial drugs onto the surface of nanoparticles to enhance their therapeutic effectiveness against VL. Further work is warranted, involving more in-depth mechanistic studies and in vivo investigations to develop safe and effective nanomedicines.