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Reduced graphene oxide decorated with gold nanoparticle as signal amplification element on ultra-sensitive electrochemiluminescence determination of caspase-3 activity and apoptosis using peptide based biosensor
摘要： Introduction: Growing demands for ultrasensitive biosensing have led to the development of numerous signal amplification strategies. In this report, a novel electrochemiluminescence (ECL) method was developed for the detection and determination of caspase-3 activity based on reduced graphene oxide sheets decorated by gold nanoparticles as signal amplification element and horseradish peroxidase enzyme (HRP) as ECL intensity enhancing agent. Methods: The ECL intensity of the luminol was improved by using the streptavidin coated magnetic beads and HRP in the presence of hydrogen peroxide. The cleavage behavior of caspase-3 was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques using biotinylated peptide (DEVD containing peptide) which was coated on reduced graphene oxide decorated with gold nanoparticle. The surface modification of graphene oxide was successfully confirmed by FTIR, UV-vis and x-ray spectroscopy. Results: ECL based biosensor showed that the linear dynamic range (LDR) and the lower limit of quantification (LLOQ) were 0.5-100 and 0.5 femtomolar (fM), respectively. Finally, the performance of the engineered peptide based biosensor was validated in the A549 cell line as real samples. Conclusion: The prepared peptide based biosensor could be considered as an excellent candidate for early detection of apoptosis, cell turnover, and cancer related diseases.
关键词： DEVD-peptide,Electrochemiluminescence,Apoptosis,Reduced graphene oxide,Caspase-3,Gold nanoparticle
更新于2025-09-04 15:30:14
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Dual?Wavelength Ratiometric Electrochemiluminescence Immunosensor for Cardiac Troponin I Detection
摘要： Ratiometric electrochemiluminescence (ECL) has attracted special focus in biological analysis field because it could eliminate the environmental interference to gain precise measurement. Herein, a dual?wavelength ratiometric ECL biosensor was designed for detection of cardiac troponin I (cTnI), where (4,4’?dicarboxylicacid?2,2’?bipyridyl) ruthenium(II) (Ru(dcbpy)3 2+) and Au nanoparticles loaded graphene oxide/polyethyleneimine (GPRu?Au) nanomaterial acts as an acceptor, and Au nanoparticles modified graphitic phase carbon nitride nanosheets composite (Au?CNN) acts as donor. Au?CNN shows high and steady ECL signal centered at 455 nm, which is well matched with the adsorption of GPRu?Au, thereby a high efficient electrochemiluminescent resonance energy transfer (ECL?RET) sensing platform is designed. AuNPs facilitate the immobilization of antibody on the nanomaterials through Au?N bond. The high surface area of graphene oxide/polyethyleneimine allows a large number of Ru(dcbpy)3 2+ to be loaded, which immensely amplify the ECL signal. This sensing platform exhibits outstanding analytical performance toward cTnI with a detection limit of 3.94 fg/mL (S/N=3). The high reliability, selectivity and sensitivity of this ratiometric ECL biosensor provides a versatile sensing platform for the bioanalysis.
关键词： carbon nitride nanosheets,ECL biosensor,graphene oxide,Ratiometric electrochemiluminescence,cardiac troponin I,Au nanoparticles
更新于2025-09-04 15:30:14