Plasmonic luminescent core-shell nanocomposites-enhanced chemiluminescence arising from the decomposition of peroxomonosulfite

A chemiluminescence-based catalase assay using H2O2-sensitive CdTe quantum dots

A method is described for the chemiluminescence based determination of the activity of catalase (CAT) using H₂O₂-sensitive CdTe quantum dots (QDs). It is based on the finding that the chemiluminescence (CL) of the CdTe/H₂O₂ system is reduced due to the consumption of H₂O₂ by the catalytic action of CAT. The Michaelis constant is calculated to be 519 ± 27 mM, showing the potential of the method to accurately measure the K_m compared to the standard method. The method does not require QDs to be conjugated to biological/organic molecules and therefore is considered to be a rapid and convenient method for determination of CAT in real samples. At an incubation time of 2 s, the LOD was calculated to be 4.5 unit/mL, with a linear range from 6 to 400 unit/mL. The assay is sensitive, simple, and suitable for practical applications. Graphical abstract Schematic representation of chemiluminescence-based catalase U(CAT) assay using the CdSe QD/H₂O₂ system. The reduction of H₂O₂ is reflected by the chemiluminescence of the QDs. A mechanism is put forward based on the changes in chemiluminescence intensity of the QDs by the consumption of H₂O₂ due to the catalytic action of CAT.

Recent advances in chemiluminescence based on carbonaceous dots

Herein, a broad overview concerning the most recent progress of carbon dots (CDs) in chemiluminescence (CL) as well as the mechanisms and applications are presented. CDs have excellent optical and electronic properties and are very important advancement in the fast growing domain of nanotechnology. CDs enhance the ultraweak CL of different systems. The mechanisms and applications of these enhanced CL reactions are discussed. It is worthy to note that CDs participate in CL reactions as catalysts, energy acceptors or are directly involved in redox reactions with radicals in CL systems. Sometimes, these processes taking place simultaneously to enhance CL intensity. In this report, recent advances in CD based CL are comprehensively summarized and their applications in detection of various reagents and biological molecules are reviewed. The challenges and future prospects of this field are also discussed.

Enhanced chemiluminescence CdSe quantum dots by histidine and tryptophan

The enhancing effect of histidine and tryptophan on chemiluminescence (CL) of CdSe quantum dots (QDs)-H2O2 system was studied. This reaction is based on the catalytic effect of amino acids, causing a significant increase in the light emission, as a result of the reaction of quantum dots (QDs) with hydrogen peroxide. In the optimum conditions, this method was satisfactorily described by linear calibration curve in the range of 0.66-35.5 μM and 0.83-35.1 μM for histidine and tryptophan, respectively. The effect of various parameters such as concentration of CdSe QDs, concentration of H2O2 and concentration of imidazole on the intensity of CL system were studied. The main experimental advantage of the proposed method is it's selective to two amino acids compared with other amino acids.

A label-free DNAzyme-cleaving fluorescence method for the determination of trace Pb(2+) based on catalysis of AuPd nanoalloy on the reduction of rhodamine 6G

The substrate chain of double-stranded DNA (dsDNA) could be specifically cleaved by Pb(2+) to release single-stranded DNA (ssDNA) that adsorbs onto the AuPd nanoalloy (AuPdNP) to form a stable AuPdNP-ssDNA complex, but the dsDNA can not protect AuPdNPs in large AuPdNP aggregates (AuPdNPA) under the action of NaCl. AuPdNP-ssDNA and large AuPdNPA could be separated by centrifugation. On increasing the concentration of Pb(2+) , the amount of released ssDNA increased; AuPdNP-ssDNA increased in the centrifugation solution exhibiting a catalytic effect on the slow reaction of rhodamine 6G (Rh6G) and NaH2 PO2 , which led to fluorescence quenching at 552 nm. The decrease in fluorescence intensity (ΔF) was linear to the concentration of Pb(2+) within the range 0.33-8.00 nmol/L, with a detection limit of 0.21 nmol/L. The proposed method was applied to detect Pb(2+) in water samples, with satisfactory results.

Tuning of the near-infrared localized surface plasmon resonance of Cu2−xSe nanoparticles with lysozyme-induced selective aggregation

Poly(styrene sulfonic acid)sodium stabilized Cu_2−xSe nanoparticles (PSS–Cu_2−xSe NPs) with localized surface plasmon resonance (LSPR) absorption centered at 980 nm can be selectively aggregated by lysozyme (Lys) through the electrostatic attraction, giving rise to a red shift of the LSPR in the near-infrared (NIR) region.