Raghumani Singh Ningthoujam

A series of highly crystalline and uniform-sized monodisperse Li+ codoped NaYF4:Ho3+, Yb3+ (YHYL) nanoparticles are successfully synthesized via a thermolysis approach by varying Li+ (0–15 at %) and Yb3+ (0–20 at %) concentrations. Li+ doping not only increases the crystallite size but also enhances the luminescence intensity by 60 times. Upon excitation with a 980 nm laser, it produces a super-bright green emission. Highly water-dispersible nanoparticles are obtained by a two-step ligand exchange method with five different capping agents, which have their own characteristic features in biomedical applications. HCl-washed NaYF4:2 at % Ho3+, 20 at % Yb3+, 10 at % Li+ (YHYL-10-HCl) nanoparticles exhibit high biocompatibility in the WI-26 normal human cell line and can therefore be utilized for ex vivo imaging, anticounterfeiting, and noncontact-based optical temperature sensors under NIR excitation. After chitosan coating, YHYL-10-chitosan nanoparticles demonstrate enhanced biocompatibility in the MCF-7 cancer cell line, as well as impressive hemocompatibility in human blood. Hence, chitosan-coated YHY, YHYL-2, and YHYL-10 nanoparticles are subsequently evaluated for multiphoton in vitro imaging, including Z-stack 3D imaging, suggesting internalization of chitosan-coated nanoparticles in MCF-7 and A549 cancer cell lines under 980 nm laser excitation.

Evolution of 2 phases – cubic (CaF ₂ host) and hexagonal (CeF ₃ host) – in over-doping of Ce ³⁺ ions in CaF ₂ :Tb ³⁺ (Ce ³⁺ = 15–23 at%; Tb ³⁺ = 5 at.%) nanocrystals.

The high incidence, aggressiveness, and chemo-refractory nature of cervical and triple-negative breast cancers (TNBC) warrant the development of targeted chemotherapy strategies for improving their therapeutic outcomes. The present study reports the design and preparation of highly monodispersed, biocompatible, and hemocompatible Ce–Tb-doped core@shell NaGdF4:20Ce@NaGdF4:5Tb (CS) nanorods prepared by a thermolysis process with an aim to enhance drug accumulation and site-specific chemotherapy in two aggressive drug-resistant human cancer cell lines, namely, cervical and TNBC. The nanorods were coated with silica to impart aqueous dispersibility, followed by covalent conjugation with folic acid, enabling their application in the site-specific delivery of anticancer drug, doxorubicin hydrochloride (DOX). MTT assay suggested a dose- and time-dependent enhancement in DOX-induced cytotoxicity of DOX-loaded CS (CS@Si-NH2–FA-DOX) in folate receptor overexpressing cervical (KB) and TNBC (MDA MB-231) cells in comparison to normal human mammary epithelial cells (MCF 10A) and human lung fibroblast cells (WI26VA4). IC50 values of CS@Si-NH2–FA-DOX were found to be ∼10–40-fold lower in KB and MDA MB-231 compared to normal cell lines, corroborating highly cancer-specific chemotherapeutic efficacy. The enhanced anticancer efficacy of CS@Si-NH2–FA-DOX was further supported by ∼3–5-fold higher intracellular uptake in both KB and MDA MB-231 cells in comparison to free DOX, as investigated by flow cytometry analysis. Pertinently, confocal studies validated that CS@Si-NH2–FA-DOX are able to deliver DOX to its intracellular target, i.e., nucleus, resulting in a significant enhancement of cytotoxicity as compared to free DOX. Furthermore, pretreatment of KB cells with pan caspase inhibitor, Z-VAD-fmk, showed significantly higher (∼2-fold) rescue after treatment with CS@Si-NH2–FA-DOX as compared to free DOX, suggesting a higher induction of apoptotic cell death by CS@Si-NH2–FA-DOX. Thus, CS@Si-NH2–FA-DOX nanorods are promising to be used as a nanodelivery vehicle for targeted chemotherapy and also for circumventing the chemo-resistance associated with cervical and TNBC cancers.