Clarification of the binding model of lead(II) with a highly sensitive and selective fluoroionophore sensor by spectroscopic and structural study

Tryptophan conjugated magnetic nanoparticles for targeting tumors overexpressing indoleamine 2,3 dioxygenase (IDO) and L-type amino acid transporter

Tryptophan is an amino acid required by all life forms for protein synthesis and other important metabolic functions. It is metabolized in the body using the kynurenine pathway which involves the enzyme indoleamine 2,3 dioxygenase (IDO) and its transport is regulated through the L-type amino acid transporters (LAT 1). IDO and LAT 1 are found to be overexpressed in many cancers i.e., ovarian, lung colorectal etc. In this study we have used this specific interaction as the basis for designing diagnostic agent based on iron oxide nanoparticles which can specifically target the IDO/LAT 1 over expressing tumors. We have conjugated tryptophan to the surface of super-paramagnetic nanoparticles chemically using 3-aminopropyltrimethoxysilane as a linker. The synthesized tryptophan conjugated magnetic nano-conjugate has been characterized using FTIR, UV-Vis, TEM for its shape size, charge and NMR and Mass for conjugation. The magnetization studies show decrease in the magnetic behavior after conjugation however the desired super-paramagnetic property is still retained as shown by the signature sigmoidal B-H curve. The nano-conjugate shows minimal cytotoxicity over 24 h as shown by the SRB assay in two cell lines A-549, MCF-7. Using 99mTc labeling the biodistribution and the blood kinetics of the magnetic nano-conjugate was evaluated. The study highlights the suitability of the designed magnetic Nano bioconjugate as a potential bimodal diagnostic agent.

Fluorescent sensor based models for the detection of environmentally-related toxic heavy metals

The quest for industrial and biotechnological revolution has been contributed in increasing environmental contamination issues, worldwide. The controlled or uncontrolled release of hazardous pollutants from various industrial sectors is one of the key problems facing humanity. Among them, adverse influences of lead, cadmium, and mercury on human health are well known to cause many disorders like reproductive, neurological, endocrine system, and cardiovascular, etc. Besides their presence at lower concentrations, most of these toxic heavy metals are posing noteworthy toxicological concerns. In this context, notable efforts from various regulatory authorities, the increase in the concentration of these toxic heavy metals in the environment is of serious concern, so real-time monitoring is urgently required. This necessitates the exploration for novel and efficient probes for recognition of these toxic agents. Among various methodologies adopted for tailoring such probes, generally the methodologies, in which changes associated with spectral properties, are preferred for the deceptive ease in the recognition process. Accordingly, a promising modality has emerged in the form of radiometric and colorimetric monitoring of these toxic agents. Herein, we review fluorescent sensor based models and their potentialities to address the detection fate of hazardous pollutants for a cleaner environment. Second, recent advances regarding small molecule and rhodamine-based fluorescent sensors, radiometric and colorimetric probes are discussed. The information is also given on the photoinduced electron transfer (PET) mechanism, chelation enhancement fluorescence (CHEF) effect and spirocyclic ring opening mechanism.

Fabrication of novel chemosensors composed of rhodamine derivative for the detection of ferric ion and mechanism studies on the interaction between sensor and ferric ion

This paper presents the design and preparation of novel fluorescence chemosensors for detection ferric ions based on rhodamine derivatives, and studies on the recognition mechanisms and interaction between probes and metal ions.