Chemiluminescence Emission Of Luminol Research Articles

On the chemiluminescence emission of luminol: protic and aprotic solvents and encapsulation to improve the properties in aqueous solution.

Luminol is a popular molecule that is currently gaining further interest due to its potential role for non-invasive cancer treatments. Design of more efficient derivatives in this context would benefit from a clear knowledge on the origin of the distinct intensity and spectroscopic properties in protic and aprotic solvents observed experimentally, which are still not rationalized. By efficiently combining molecular dynamics, quantum methodologies based on density functional theory and multiconfigurational quantum chemistry and hybrid approaches, and developing herein a computational approach for accurately determining "molar negative extinction (or gain) coefficients of emission", we firstly demonstrate that the amino and imino forms of the 3-aminophthalate dianion are responsible for the chemiluminescence in protic and aprotic medium, respectively. Secondly, we show that the coupling between the adjacent amino and carboxylate groups of luminol existing in aprotic solvents must be kept in aqueous solution to increase the chemiexcitation and emission intensity. Thirdly, modifications of luminol are proposed and simulated showing improved performances as compared to the parent molecule (stronger emission electronic transition and longer emission wavelengths) under the physiological conditions of relevance in biological and medical applications.

A self-powered photoelectrochemical biosensor for H2O2, and xanthine oxidase activity based on enhanced chemiluminescence resonance energy transfer through slow light effect in inverse opal TiO2

TiO2 inverse opal photonic crystals (IOPCs) were fabricated by using polystyrene template. TiO2 IOPCs based photoelectrochemical (PEC) biosensor was fabricated for the precise and stable detection of Heme without external irradiation. Then, the sensitization of TiO2 IOPCs was fulfilled with CdS quantum dots (QDs) by SILAR method to form ITO-TiO2 IOPCs–CdS:Mn electrode, which in turn was used to construct a PEC biosensor. The uniform porous structure of IOPCs with a large surface area is conducive to the excellent electronic transmission and QDs deposition. Also, the energy level matching between the conduction bands of CdS QDs and TiO2 IOPCs widened the range of light absorption, allowing for electron injection from excited CdS QDs to TiO2 upon luminol chemiluminescence, which enhanced the photocurrent. Furthermore, when the red edge of the photonic stop band of TiO2 IOPCs overlapped with the band gap of TiO2, and chemiluminescence emission of luminol, a substantial photocurrent increment was observed due in part to the slow light effect. The biosensor possesses a large linear detection range of 0.063–4 mM with a LOD of 19 μM for H2O2. Also, xanthine oxidase activity was determined with a linear measurement range of 0.01–15 mU/mL. Our strategy opens a new horizon to IOPCs based and QDs sensitized PEC sensing, which could be more sensitive, convenient and inexpensive for clinical and biological analysis. As far as we know, the largest photocurrent generation by luminol chemiluminescence was observed thanks to the use of semiconducting hybrid IOPCs material even at 0 V.

Graphitic C3N4 nanosheet and hemin/G-quadruplex DNAzyme-based label-free chemiluminescence aptasensing for biomarkers

Here we first reported that graphitic carbon nitride nanosheet (g-C3N4 NS) could effectively quench the chemiluminescence (CL) of luminol-hydrogen peroxide (H2O2) system. According to the new discovery, a label-free and homogeneous CL aptasensing platform was designed for sensitive detecting of biomarkers. In the absence of target, DNA probe containing hemin/G-quadruplex DNAzyme structure was adsorbed on the surface of g-C3N4 NS, causing the CL quenching of luminol through an electron transfer process. However, in the presence of the target, a DNA-DNA duplex was formed due to DNA hybridization reaction and target recognition effect, which could not be adsorbed onto the g-C3N4 NS surface because of its weak affinity. Thus, the electron transfer was blocked and the CL emission of luminol could be enhanced. The proposed CL aptasensor could detect carcinoembryonic antigen (CEA) with a detection limit of 63.0 pg/mL and it can also be used as a general detecting strategy for adenosinetriphosphate (ATP) detection. This aptasensing platform exhibited high sensitivity toward biomarkers and the probe need not be labeled, showing great promise for disease diagnosis.

Novel Iron(III)-Based Metal-Organic Gels with Superior Catalytic Performance toward Luminol Chemiluminescence.

Novel metal-organic gels (MOGs) consisting of iron (Fe3+) as the central ion and 1,10-phenanthroline-2,9-dicarboxylic acid (PDA) as the ligand were synthesized by a mild facile strategy. The Fe(III)-containing metal-organic xerogels (Fe-MOXs), obtained after removing the solvents in MOGs, were found to exhibit outstanding performance in the catalysis of luminol chemiluminescence (CL) for the first time even in the absence of extra oxidants such as hydrogen peroxide. The possible CL mechanism was discussed according to the electro/optical measurements, including electron paramagnetic resonance (EPR), UV-vis absorption, and CL spectra, as well as the effects of radical scavengers on Fe-MOXs-catalyzed luminol CL system, suggesting that the CL emission of luminol might originate from the intrinsic oxidase-like catalytic activity of Fe-MOXs on the decomposition of dissolved oxygen. Additionally, the potential practical application of the resulting luminol-Fe-MOXs system was evaluated by the quantitative analysis of dopamine. Good linearity over the range from 0.05 to 0.6 μM was obtained with the limit of detection (LOD, 3σ) of 20.4 nM and acceptable recoveries ranging from 98.6 to 105.4% in human urine. These results may open up the promising application of novel metal-organic gels as highly effective catalysts in the field of chemiluminescence.

CdS/MoS2 heterojunction-based photoelectrochemical DNA biosensor via enhanced chemiluminescence excitation.

This work developed a CdS/MoS2 heterojunction-based photoelectrochemical biosensor for sensitive detection of DNA under the enhanced chemiluminescence excitation of luminol catalyzed by hemin-DNA complex. The CdS/MoS2 photocathode was prepared by the stepwise assembly of MoS2 and CdS quantum dots (QDs) on indium tin oxide (ITO), and achieved about 280% increasing of photocurrent compared to pure CdS QDs electrode due to the formation of heterostructure. High photoconversion efficiency in the photoelectrochemical system was identified to be the rapid spatial charge separation of electron-hole pairs by the extension of electron transport time and electron lifetime. In the presence of target DNA, the catalytic hairpin assembly was triggered, and simultaneously the dual hemin-labeled DNA probe was introduced to capture DNA/CdS/MoS2 modified ITO electrode. Thus the chemiluminescence emission of luminol was enhanced via hemin-induced mimetic catalysis, leading to the physical light-free photoelectrochemical strategy. Under optimized conditions, the resulting photoelectrode was proportional to the logarithm of target DNA concentration in the range from 1 fM to 100 pM with a detection limit of 0.39 fM. Moreover, the cascade amplification biosensor demonstrated high selectivity, desirable stability and good reproducibility, showing great prospect in molecular diagnosis and bioanalysis.

Flow injection chemiluminescence detection and solvent extraction for human skin ointment dexamethasone acetate absorption analysis and the reaction mechanism study

A flow-injection chemiluminescence (CL) method coupled with solvent extraction for the determination of dexamethasone acetate (DA) in ointment was presented in this paper. It was based on the enhancing effect of the studied drug on CL emission of luminol–K 3Fe(CN) 6 system. This method has the advantages of simple sample treatment, cheap instrumentation and rapid detection. Under the optimum conditions, relative CL intensities were proportional to DA concentrations in the 0.044–4.4 μg ml −1 range. The limit of detection was 0.01 μg ml −1 (3 σ) for DA. The method was applied to DA quantification in commercial DA ointment pharmaceutical and to human skin DA absorption analysis. Experiments were performed to evaluate the nature of DA enhanced luminol–K 3Fe(CN) 6 CL reaction. Based on the experimental results, it was suggested that in this CL system, DA was oxidized by K 3Fe(CN) 6 to form a medium product (DAox), DAox oxidized luminol with a faster kinetic step comparing with K 3Fe(CN) 6 oxidized luminol to an active form. As a result, DA speed the luminol CL reaction, and finally intensified the CL signal.