The evolution of photoelectrochemical (PEC) bioanalysis has resulted in substantial progress in its analytical performance and biodetection applications. The aim of this review is to provide a ...panoramic snapshot of the state of the art in this dynamically developing field, with special emphasis on PEC DNA analysis, immunoassay, enzymatic biosensing and cell-related detection. The future prospects in this area are also evaluated and discussed. This work will serve as a useful source to inform the interested audience of the latest developments and applications in the field of PEC bioanalysis.
Electrogenerated chemiluminescence, also known as electrochemiluminescence (ECL), is an electrochemically induced production of light by excited luminophores generated during redox reactions. It can ...be used to sense the charge transfer and related processes at electrodes
via
a simple visual readout; hence, ECL is an outstanding tool in analytical sensing. The traditional ECL approach measures averaged electrochemical quantities of a large ensemble of individual entities, including molecules, microstructures and ions. However, as a real system is usually heterogeneous, the study of single entities holds great potential in elucidating new truths of nature which are averaged out in ensemble assays or hidden in complex systems. We would like to review the development of ECL intensity and imaging based single entity detection and place emphasis on the assays of small entities including single molecules, micro/nanoparticles and cells. The current challenges for and perspectives on ECL detection of single entities are also discussed.
We summarize the history and recent development that has been made in the ECL detection of single entities.
Photoelectrochemical DNA Biosensors Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan
Chemical reviews,
08/2014, Volume:
114, Issue:
15
Journal Article
Peer reviewed
Zhao et al explore photoelectrochemical (PEC) DNA biosensors, focusing on topics such as transducers, probe immobilization, DNA interactions, and PEC transduction of DNA interactions.
Wu et al explore electrochemically generated versus photoexcited luminescence from semiconductor nanomaterials. They focus on the fundamentals of the electrochemical luminescence and photoexcited ...luminescence, as well as their analytical applications.
The aggregation‐induced electrochemiluminescence (AIECL) of carboranyl carbazoles in aqueous media was investigated for the first time. Quantum yields, morphologies, and particle sizes were observed ...to determine the electrochemiluminescence (ECL) performance of these aggregated organic dots (ODs). All compounds exhibit much higher ECL stability and intensity than the carborane‐free compound, demonstrating the essential role of the carboranyl motif. Moreover, the results of cyclic voltammetry (CV) suggest that oxidation/reduction reactions take place at the carboranyl motif. The excited states of ODs were proposed to be generated by the mechanism of surface state transitions. More importantly, these compounds show a reductive–oxidative mechanism in contrast to other organic materials that show oxidative–reductive mechanisms. Our experiments and data have established the relation between AIE organic structures and ECL properties that has a strong potential for biological and diagnostic applications.
Carborane‐based AIEgens: The reductive–oxidative aggregation‐induced electrochemiluminescence (AIECL) of carboranyl carbazoles in air‐saturated aqueous media was investigated. Mechanistic studies indicate that the carboranyl motif plays vital role in the high ECL intensity and stability of the aggregates.
We report a photodynamic therapy driven by electrochemiluminescence (ECL). The luminescence generated by Ru(bpy)32+ and co‐reactant tripropylamine (TPA) pair acts as both optical readout for ECL ...imaging, and light source for the excitation of photosensitizer to produce reactive oxygen species (ROS) in photodynamic therapy (PDT) system. The ECL‐driven PDT (ECL‐PDT) relies on the effective energy transfer from ECL emission to photosensitizer chlorin e6 (Ce6), which sensitizes the surrounding O2 into ROS. The dynamic process of gradual morphological changes, the variation of cell‐matrix adhesions, as well as the increase of cell membrane permeability in the process of ECL‐PDT were monitored under ECL microscopy (ECLM) with good spatiotemporal resolution. Combining real‐time imaging with ECL‐PDT, this new strategy provides not only new insights into dynamic cellular processes, but also promising potential of ECL in clinical applications.
A system for photodynamic therapy driven by electrochemiluminescence (ECL) is reported. The ECL generated by the Ru(bpy)32+/TPA pair acts as both the optical readout for the monitoring of the dynamic cellular processes and the light source for the excitation of a photosensitizer to produce cytotoxic ROS.
Cuproptosis is a new form of programmed cell death and exhibits enormous potential in cancer treatment. However, reducing the undesirable Cu ion release in normal tissue and maximizing the ...copper‐induced therapeutic effect in cancer sites are two main challenges. In this study, we constructed a photothermally triggered nanoplatform (Au@MSN‐Cu/PEG/DSF) to realize on‐demand delivery for synergistic therapy. The released disulfiram (DSF) chelated with Cu2+ in situ to generate highly cytotoxic bis(diethyldithiocarbamate)copper (CuET), causing cell apoptosis, and the formed Cu+ species promoted toxic mitochondrial protein aggregation, leading to cell cuproptosis. Synergistic with photothermal therapy, Au@MSN‐Cu/PEG/DSF could effectively kill tumor cells and inhibit tumor growth (inhibition rate up to 80.1 %). These results provide a promising perspective for potential cancer treatment based on cuproptosis, and may also inspire the design of advanced nano‐therapeutic platforms.
A gold‐nanorod‐based, copper‐doped, and disulfiram (DSF)‐loaded multifunctional therapeutic nanoplatform (Au@MSN‐Cu/PEG/DSF) was fabricated to deliver DSF and Cu2+ into cancer cells efficiently. A photothermal effect triggered on‐command payload release remotely to form cytotoxic bis(diethyldithiocarbamate)copper (CuET) and Cu+ in situ. This cuproptosis‐based strategy offers synergistic therapeutic modalities.
The emergence of the rising alliance between aggregation‐induced emission (AIE) and electrochemiluminescence (ECL) is defined as aggregation‐induced electrochemiluminescence (AIECL). The booming ...science of AIE has proved to be not only distinguished in luminescent materials but could also inject new possibility into ECL analysis. Especially in the aqueous phase and solid state for hydrophobic materials, AIE helps ECL circumvent the dilemma between substantial emission intensity and biocompatible media. The wide range of analytes makes ECL an overwhelmingly interesting analytical technique. Therefore, AIECL has gained potential in clinical diagnostics, environmental assays, and biomarker detections. This review will focus on introduction of the novel concept of AIECL, current applied luminophores, and related applications developed in recent years.
Coupling AIE and ECL: This Minireview highlights the recent advances in principles, mechanisms, luminophore structures, and applications of aggregation‐induced electrochemiluminescence (AIECL) in order to promote rapid development of this area.
We report here a tumor‐pretargted theranostic approach for multimodality imaging‐guided synergistic cancer PDT by cascade alkaline phosphatase (ALP)‐mediated in situ self‐assembly and bioorthogonal ...inverse electron demand Diels–Alder (IEDDA) reaction. Using the enzymatic catalysis of ALP that continuously catalyses the dephosphorylation and self‐assembly of trans‐cyclooctene (TCO)‐bearing P‐FFGd‐TCO, a high density of fluorescent and magnetic TCO‐containing nanoparticles (FMNPs‐TCO) can be synthesized and retained on the membrane of tumor cells. They can act as ‘artificial antigens’ amenable to concurrently capture lately administrated tetrazine (Tz)‐decorated PS (775NP‐Tz) and carbonic anhydrase (CA) inhibitor (SA‐Tz) via the fast IEDDA reaction. This two‐step pretargeting process can further induce FMNPs‐TCO regrowth into microparticles (FMNPs‐775/SA) directly on tumor cell membranes, which is analyzed by bio‐SEM and fluorescence imaging. Thus, efficient enrichment of both SA‐Tz and 775NP‐Tz in tumors can be achieved, allowing to alleviate hypoxia by continuously inhibiting CA activity and improving PDT of tumors. Findings show that subcutaneous HeLa tumors could be completely eradicated and no tumor recurred after irradiation with an 808 nm laser (0.33 W cm−2, 10 min). This pretargeted approach may be applied to enrich other therapeutic agents in tumors to improve targeted therapy.
A two‐step tumor‐pretargeted approach for multimodal imaging‐guided cancer theranostics via cascade alkaline phosphatase (ALP)‐mediated in situ self‐assembly and bioorthogonal inverse electron demand Diels–Alder (IEDDA) reaction enhances the accumulation of carbonic anhydrase inhibitors (SA‐Tz) and photosensitizers (775NP‐Tz) at the tumor site, efficiently alleviating hypoxic tumors and augmenting synergistic PDT efficacy in vivo.
Ionic current rectification (ICR) based nanopipettes allow accurate monitoring of cellular behavior in single living cells. Herein, we proposed a 30 nm nanopipette functionalized with G‐quadruplex ...DNAzyme as an efficient biomimetic recognizer for ROS generation at subcellular level via the changes of current–voltage relationship. Taking advantages of the ultra‐small tip, the nanopipette could penetrate into a single living cell repeatedly or keep measuring for a long time without compromising the cellular functions. Coupled with precision nanopositioning system, generation of ROS in mitochondria in response to cell inflammation was determined with high spatial resolution. Meanwhile, the changes of aerobic metabolism in different cell lines under drug‐induced oxidative stress were monitored continuously. We believe that the ICR‐nanopipette could be developed as a powerful approach for the study of cellular activities via electrochemical imaging in living cells.
Electrochemical imaging: An ionic current rectification (ICR) based nanopipette with a 30 nm nanotip was fabricated for continuous monitoring of aerobic metabolism processes in single living cells at subcellular level. The cells produced reactive oxygen species (ROS) in mitochondria. The inner surface of the nanopipette was functionalized with G‐quadruplex DNAzyme.
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