Chapters authored
Mn-Doped ZnSe Quantum Dots as Fluorimetric Mercury Sensor
Quantum dots (QDs), because of their exciting optical properties, have been explored as alternative fluorescent sensors to conventional organic fluorophores which are routinely employed for the detection of various analytes via fluorometry. QD probes can detect toxic metal ions, anions, organic molecules with good selectivity and sensitivity. This chapter investigates the synthesis of Mn-doped ZnSe QDs using nucleation-doping strategy. The as-synthesized QDs were characterized by various analytical tools such as ultraviolet-visible (UV-vis) absorption, photoluminescence (PL) spectroscopy, X-ray diffractometry (XRD) and transmission electron microscopy (TEM). It was found that Mn doping of QDs significantly increases the PL intensity. The PL of the resulting QDs was examined in the presence of different metal ions to check its selective response. Among the various metal ions, Hg2+ exhibits a drastic quenching of the QD’s emission intensity. A Stern-Volmer plot of [Hg2+] sensing using the as-synthesized QDs showed linearity in the range of 0–30 × 10−6 ML−1 with the regression coefficient R2 = 0.99. The detection limit was found to be 6.63 × 10−7 ML−1. Thus, the present Mn-doped ZnSe QDs represent a simple, non-toxic fluorescent probe for the qualitative and quantitative detection of mercury ions in aqueous samples.
Part of the book: Nonmagnetic and Magnetic Quantum Dots
Application of Quantum Dots in Lateral Flow Immunoassays: Non-Communicable and Communicable Diseases
Quantum Dots (QDs) are ideal fluorescent labels for lateral flow assays (LFA) due to their unique optical properties and resistance to chemical and photo-degradation. Lateral flow assay, known as immunochromatography test, is a diagnostic strip test that uses paper or membrane-based devices to detect the presence/absence of an analyte with the pregnancy test, the most known LFA. Diagnostic tools for non-communicable (NCDs) and communicable diseases (CDs) are available. However, other NCDs and CDs do not have LFAs as first-line diagnosis/point-of-care. QDs are promising fluorescent labels as they improve the LFA’s colourimetric sensitivity and fluorescence stability. This chapter discusses the tailoring and application of QDs in LFA. Particular focus on the applications of QDs in LFA for detecting or screening NCDs (i.e. cancers etc.) and CDs (i.e. SARS-CoV-2, HIV/AIDs etc.). The book chapter concludes by discussing different challenges and perspectives of QDs in LFA.
Part of the book: Quantum Dots