Development of a highly sensitive chemiluminescent assay for hydrogen peroxide under neutral conditions using acridinium ester and its application to an enzyme immunoassay

What Other Than Acridinium Esters? Computational Search for New Acridinium-Based Chemiluminogens

The rapid increase in disease prevalence in the world makes it extremely important to search for new or develop existing diagnostic methods, for example, chemiluminescent labeling used in immunodiagnostics. At present, acridinium esters are willingly used as chemiluminogenic fragments of labels. However, the search for new chemiluminogens that are particularly efficient is the main task of our studies. The density functional theory (DFT) and time-dependent (TD) DFT methods were used to obtain thermodynamic and kinetic results concerning the chemiluminescence and competitive dark reactions, which indicated whether some of the scrutinized derivatives have better characteristics than the chemiluminogens used so far. Synthesis of these candidates for efficient chemiluminogens, followed by studies of their chemiluminescent properties, and ultimately in chemiluminescent labeling, are further steps to confirm their potential applicability in immunodiagnostics.

Recent Advances in Nanomaterial-Based Chemiluminescence Probes for Biosensing and Imaging of Reactive Oxygen Species

Reactive oxygen species (ROS) play important roles in organisms and are closely related to various physiological and pathological processes. Due to the short lifetime and easy transformation of ROS, the determination of ROS content in biosystem has always been a challenging task. Chemiluminescence (CL) analysis has been widely used in the detection of ROS due to its advantages of high sensitivity, good selectivity and no background signal, among which nanomaterial-related CL probes are rapidly developing. In this review, the roles of nanomaterials in CL systems are summarized, mainly including their roles as catalysts, emitters, and carriers. The nanomaterial-based CL probes for biosensing and bioimaging of ROS developed in the past five years are reviewed. We expect that this review will provide guidance for the design and development of nanomaterial-based CL probes and facilitate the wider application of CL analysis in ROS sensing and imaging in biological systems.

Solvent effect on chemiluminescence of acridinium thioester: a computational study

Chemiluminescent labelling, which is one of the promising procedures of modern immunodiagnostics, is increasingly carried out using acridinium derivatives, oxidant and alkaline aqueous environment. However, the efficiency of chemiluminescence of luminol or acridinium esters is higher in non-aqueous solvents such as DMSO or acetonitrile. Therefore, the search for a new environment of chemiluminescence reaction, especially this characterized by the higher quantum yield of chemiluminescence, is one of the aims of the research undertaken. Using computational methods (DFT and TD DFT with PCM model of solvent), we examined thermodynamic and kinetic data concerning the chemiluminescence and competitive dark pathways. Our results suggest that better characteristics of chemiluminescence reaction of acridinium thioester are observed in nonpolar solvents, such as methylcyclohexane, n-hexane and n-pentane, than in aqueous media used so far. Further experimental verification is necessary to confirm the possible application of proposed nonpolar solvents in chemiluminescent labelling and hence in immunodiagnostics.

Acridinium Ester Chemiluminescence: Methyl Substitution on the Acridine Moiety

Methyl groups were introduced on the acridine moiety in chemiluminescent acridinium esters that have electron-withdrawing groups (trifluoromethyl, cyano, nitro, ethoxycarbonyl) at the 4-position on the phenyl ester. The introduction of methyl groups at the 2-, 2,7-, and 2,3,6,7-positions on the acridine moiety shifted the optimal pH that gave relatively strong chemiluminescence intensity from neutral conditions to alkaline conditions. 4-(Ethoxycarbonyl)phenyl 2,3,6,7,10-pentamethyl-10λ⁴-acridine-9-carboxylate, trifluoromethanesulfonate salt showed long-lasting chemiluminescence under alkaline conditions. Acridinium esters to determine hydrogen peroxide concentration at pH 7-10 were newly developed.

Computational Insights on the Mechanism of the Chemiluminescence Reaction of New Group of Chemiluminogens-10-Methyl-9-thiophenoxycarbonylacridinium Cations

Immunodiagnostics, in which one of the promising procedures is the chemiluminescent labelling, is essential to facilitate the detection of infections in a human organism. One of the standards commonly used in luminometric assays is luminol, which characterized by low quantum yield in aqueous environments. Acridinium esters have better characteristics in this topic. Therefore, the search for new derivatives, especially those characterized by the higher quantum yield of chemiluminescence, is one of the aims of the research undertaken. Using the proposed mechanism of chemiluminescence, we examined the effect of replacing a single atom within a center of reaction on the efficient transformation of substrates into electronically excited products. The density functional theory (DFT) and time dependent (TD) DFT calculated thermodynamic and kinetic data concerning the chemiluminescence and competitive dark pathways suggests that some of the scrutinized derivatives have better characteristics than the chemiluminogens used so far. Synthesis of these candidates for efficient chemiluminogens, followed by studies of their chemiluminescent properties, and ultimately in chemiluminescent labelling, are further steps to confirm their potential applicability in immunodiagnostics.

Aggregation-induced emission luminogens for RONS sensing

The development of AIE bioprobes for RONS sensing in living systems is now summarized. We discuss some representative examples of AIEgen based bioprobes in terms of their molecular design, sensing mechanism and sensitive sensing in vitro and in vivo.