Bode Phase Angle Signaling of a TB Disease Biomarker.

Tuberculosis (TB) is a worldwide burden whose total control and eradication remains a challenge due to factors including false positive/negative diagnoses associated with the poor sensitivity of the current diagnostics in immune-compromised and post-vaccinated individuals. As these factors complicate both diagnosis and treatment, the early diagnosis of TB is of pivotal importance towards reaching the universal vision of a TB-free world. Here, an aptasensor for signaling an interferon gamma (IFN-γ) TB biomarker at low levels is reported. The aptasensor was assembled through gold-thiol interactions between poly(3,4-propylenedioxythiophene), gold nanoparticles, and a thiol-modified DNA aptamer specific to IFN-γ. The aptasensor sensitively detected IFN-γ in spiked pleural fluid samples with a detection limit of 0.09 pg/mL within a linear range from 0.2 pg/mL to 1.2 pg/mL. The good performance of the reported aptasensor indicates that it holds the potential for application in the early diagnosis of, in addition to TB, various diseases associated with IFN-γ release in clinical samples.

A review on I-III-VI ternary quantum dots for fluorescence detection of heavy metals ions in water: optical properties, synthesis and application.

Heavy metal contamination remains a major threat to the environment. Evaluating the concentrations of heavy metals in water environments is a crucial step towards a viable treatment strategy. Non-cadmium photo-luminescent I-III-VI ternary QDs have attracted increasing attention due to their low toxicity and extraordinary optical properties, which have made them popular in biological applications. Recently, ternary I-III-VI-QDs have gained growing interest as fluorescent detectors of heavy metal ions in water. Here, we review the research progress of ternary I-III-VI QDs for the fluorescence detection of heavy metal ions in water. First, we summarize the optical properties and synthesis methodologies of ternary I-III-VI QDs. Then, we present various detection mechanisms involved in the fluorescence detection of heavy metal ions, which are mostly attributed to direct interaction between these unique QDs and the metal ions, seen in the form of fluorescence quenching and fluorescence enhancement. We also display the potential applications in environmental remediation such as water treatment and associated challenges of I-III-VI QDs in the fluorescence detection of Cu2+ and other metal ions.

Core-Shell Palladium Telluride Quantum Dot-Hemethiolate Cytochrome Based Biosensor for Detecting Indinavir Drug.

Indinavir is a first-generation HIV protease inhibitor anti-retroviral (ARV) drug. Due to interindividual differences in the rate of indinavir metabolism, clinicians and pharmacologists have expressed urgent need for sensor devices that will enable real time determination of appropriate dosage. In this study, an indinavir biosensor was developed by the functionalization of a cysteamine-modified gold (Cyst|Au) electrode with biocompatible core-shell 3-mercaptopropionic acid (3-MPA)-capped palladium telluride quantum dot (PdTeQD) and the heme-thiolate cytochrome P450-3A4 (CYP3A4) enzyme. The PdTeQD was capped with 3-mercaptopropionic acid (3-MPA) to improve its reactivity, biocompatibility and thermal stability. Small angle X-ray scattering (SAXS) studies revealed that the 3-MPA-PdTeQD particles formed core-shells with diameters of 4.7 nm. Fourier transformed infrared spectroscopy (FTIR) experiments confirmed the formation of 3-MPA-PdTeQD by the presence of specific COOH and CH2 FTIR signature bands. Ultraviolet-visible (UV-Vis) spectrophotometric analysis of the quantum dot, exhibited a broad characteristic band at ~320 nm, corresponding to a band gap energy (Eg) value of 3.87 eV, indicating that the QD is a semiconducting material. Cyclic voltammetry (CV) responses of the biosensor (i.e., CYP3A4|3-MPA-PdTeQD|Cyst|Au) indicated that 0.26 V was the suitable potential for measuring indinavir metabolism. The biosensor has a sensitivity, dynamic linear range (DLR) and limit of detection (LOD) values of 0.0218 µA/nM, 0.0004-0.01 nM (i.e., 3×10-7 -7×10-6 mg L-1) and 0.023×10-7 mg L-1, respectively, for indinavir. The LOD value was lower than the maximum plasma concentration (Cmax) value (0.13-8.6 mg L-1) of indinavir which is normally measure 8 h after intake. The low DLR value makes the biosensor suitable for application at point-of-care, where indinavir concentration is expected to be in ng L-1 level in physiological samples within a few minutes of the drug administration.