A sensitive immunosensor via Pd@Au0.85Pd0.15 in situ electrocatalysis generating H2O2 for quenching electrochemiluminescence of Ir(pbi)2(acac)@Ti3C2Tx MXene-PVA

The establishment of rapid target analysis methods for cytokeratin fragment antigen 21-1 (CYFRA 21-1) is urgently needed. [Ir(pbi)2(acac)] (pbi = 2-(4-bromophenyl)-1-hydrogen -benzimidazole, acac = acetylacetonate) as traditional electrochemiluminescence (ECL) luminophores has been confined due to its non-negligible dark toxicity and poor water solubility leading to poor biocompatibility and electrical conductivity as an organic molecule. Hence, to overcome this limitation, [Ir(pbi)2(acac)] can be effectively loaded on the polyvinyl alcohol hydrogel modified Ti3C2Tx MXene surface (Ir@Ti3C2Tx-PVA) as sensing platform which can emit high ECL signals. Then, a quenching strategy was proposed to fabricate an ECL sandwich immunosensor using H2O2 as quencher molecules which can generated by Pd@Au0.85Pd0.15. Especially, the generation of O2 to H2O2 can be achieved through a two-electron (2e-) reaction pathway by Pd@Au0.85Pd0.15, to overcome the restriction that the H2O2 was virtually impossible to label or immobilize on the non-enzyme nanomaterials. The proposed ECL assay achieves a response to CYFRA 21-1 within the range of 0.1 pg/mL-100 ng/mL, with a detection limit of 8.9 fg/mL (S/N = 3). This work provided a feasible tactic to seek superior-performance ECL luminophore and quencher consequently set up a novel means to makeup ultrasensitive ECL biosensor, which extended the utilization potential of Ir(pbi)2(acac) in ECL assays.

Full Electron Delocalization across the Cluster in 1,12-bisBMes2-p-carborane Radical Anion

Conjugation between three-dimensional (3D) carboranes and the attached substituents is commonly believed to be very weak. In this paper, we report that reducing 1,12-bis(BMes2)-p-carborane (B2pCab) with one electron gives a radical anion with a centrosymmetric semiquinoidal structure. This radical anion shows extensive electron delocalization between the two boron centers over the p-carborane bridge due to the overlap of carborane lowest unoccupied molecular orbital (LUMO) and the BMes2 LUMO. Unlike dianions of other C2B10H12 carboranes, which rearrange to a nido-form, two-electron reduction of B2pCab leads to a rearrangement into a basket-shaped intermediate.

Solvent Regulation Induced Cathode Aggregation-Induced Electrochemiluminescence of Tetraphenylethylene Nanoaggregates for Ultrasensitive Zearalenone Analysis

Zearalenone (ZEN) is an extremely hazardous chemical widely existing in cereals, and its high-sensitivity detection possesses significant significance to human health. Here, the cathodic aggregation-induced electrochemiluminescence (AIECL) performance of tetraphenylethylene nanoaggregates (TPE NAs) was modulated by solvent regulation, based on which an electrochemiluminescence (ECL) aptasensor was constructed for sensitive detection of ZEN. The aggregation state and AIECL of TPE NAs were directly and simply controlled by adjusting the type of organic solvent and the fraction of water, which solved the current shortcomings of low strength and weak stability of the cathode ECL signal for TPE. Impressively, in a tetrahydrofuran-water mixed solution (volume ratio, 6:4), the relative ECL efficiency of TPE NAs reached 16.03%, which was 9.2 times that in pure water conditions, and the maximum ECL spectral wavelength was obviously red-shifted to 617 nm. In addition, "H"-shape DNA structure-mediated dual-catalyzed hairpin self-assembly (H-D-CHA) with higher efficiency by the synergistic effect between the two CHA reactions was utilized to construct a sensitive ECL aptasensor for ZEN analysis with a low detection limit of 0.362 fg/mL. In conclusion, solvent regulation was a simple and efficient method for improving the performance of AIECL materials, and the proposed ECL aptasensor had great potential for ZEN monitoring in food safety.

Anisotropic growth of gold anchors on CdSe semiconductor quantum platelets for self-assembled architectures with well-connected electronic circuits for the electrochemical detection of enrofloxacin

Anisotropic growth of nanomaterials enables advances in building diverse and complex architectures, which exhibit unique properties and enrich the choice of nano-building modules for electrochemical sensor devices. Herein, an anisotropic growth method was proposed to anchor gold nanoparticles (AuNPs) onto both ends of quasi-two-dimensional CdSe semiconductor quantum nanoplatelets (NPLs), appearing with a monodisperse and uniform nano-dumbbell shape. Then, these AuNPs were exploited as natural anchor points and further initiated self-assembly to create complex architectures via dithiol bridges. Detailed studies illustrated that the covalent Se-Au bonds facilitate effective charge transfer in the internal metal-semiconductor (M-S) electric field. The narrowed energy gap and up-shifted highest occupied molecular orbital were favored for electron removal during the electro-oxidation process. The ultrathin CdSe NPLs supplied a large specific surface area, carrying remaining holes and abundant active sites for target electro-catalysis. As a result, using the assembled complex as the electrode matrix with well-connected electronic circuits, a reliable electrochemical sensor was achieved for enrofloxacin detection. Under the optimal conditions, the current response exhibits two linear dynamic ranges, 0.01-10.0 μM and 10.0-250 μM, and the detection limit was calculated as 0.0026 μM. This work not only opens up broad application prospects for heterogeneous M-S combinations as effective electrochemical matrixes but also develops reliable antibiotic assays for food and environmental safety.

Synthesis of silica-encapsulated tetraphenylethylene with aggregation-induced electrochemiluminescence resonance energy transfer for sensitively sensing microcystin-LR

The reported organic electrochemiluminescence (ECL) luminophors for the detection of various markers often suffer from intermolecular π-π stacking-induced luminophore quenching. Herein, we demonstrate one-pot synthesis of a new aggregation-induced electrochemiluminescence (AIECL) emitter (i.e., TPE@SiO2/rGO composite) for sensitive measurement of microcystin-leucine arginine (MC-LR). The TPE@SiO2/rGO composite is constructed by embedding the silica-encapsuled 1,1,2,2-tetra(4-carboxylphenyl)ethylene (TPE) in the reduced graphene oxide. In comparison with the monomer TPE, this composite exhibit high luminescence efficiency and strong ECL emission, because the AIECL phenomenon triggered by the spatial confinement effect in the SiO2 cage induces the restriction of the internal motion and vibration of molecules. Notably, this composite has distinct advantages of easy preparation, simple functionalization, and stable luminescence. Especially, the TPE@SiO2/rGO-based ECL-RET system exhibits a high quenching efficiency (ΦET) of 69.7%. When target MC-LR is present, it triggers DNA strand displacement reaction (SDR), inducing the quenching of the ECL signal of TPE@SiO2/rGO composite due to ECL resonance energy transfer between TPE@SiO2/rGO composite and methylene blue (MB). The proposed biosensor enables highly sensitive, low-cost, and robust measurement of MC-LR with a large dynamic range of 7 orders of magnitude and a detection limit of 3.78 fg/mL, and it displays excellent detection performance in complex biological matrices, holding potential applications in food safety and water monitoring.

Breaking the Base Barrier: Cu(II)-Mediated C-H Heteroarylation of o-Carboranes with Base-Sensitive Heteroaryl Halides

While cage C-arylation reactions using strong bases are among the most frequently used transformations in carborane chemistry, there has been no general solution to allow for the use of weak bases in the reaction. Moreover, base-metal-promoted C-H heteroarylation with base-sensitive heteroaryl halides remained elusive. Herein, copper-mediated cage C-H (hetero)arylation has been achieved without the need for strong bases, leading to the facile synthesis of a wide range of C-(hetero)arylated carboranes in good to excellent yields with a broad substrate scope and good functional group compatibility.

Timescale correlation of shallow trap states increases electrochemiluminescence efficiency in carbon nitrides

Highly efficient interconversion of different types of energy plays a crucial role in both science and technology. Among them, electrochemiluminescence, an emission of light excited by electrochemical reactions, has drawn attention as a powerful tool for bioassays. Nonetheless, the large differences in timescale among diverse charge-transfer pathways from picoseconds to seconds significantly limit the electrochemiluminescence efficiency and hamper their broad applications. Here, we report a timescale coordination strategy to improve the electrochemiluminescence efficiency of carbon nitrides by engineering shallow electron trap states via Au-N bond functionalization. Quantitative electrochemiluminescence kinetics measurements and theoretic calculations jointly disclose that Au-N bonds endow shallow electron trap states, which coordinate the timescale of the fast electron transfer in the bulk emitter and the slow redox reaction of co-reagent at diffusion layers. The shallow electron trap states ultimately accelerate the rate and kinetics of emissive electron-hole recombination, setting a new cathodic electrochemiluminescence efficiency record of carbon nitrides, and empowering a visual electrochemiluminescence sensor for nitrite ion, a typical environmental contaminant, with superior detection range and limit.

Optically induced charge-transfer in donor-acceptor-substituted p- and m- C2B10H12 carboranes

Icosahedral carboranes, C2B10H12, have long been considered to be aromatic but the extent of conjugation between these clusters and their substituents is still being debated. m- and p-Carboranes are compared with m- and p-phenylenes as conjugated bridges in optical functional chromophores with a donor and an acceptor as substituents here. The absorption and fluorescence data for both carboranes from experimental techniques (including femtosecond transient absorption, time-resolved fluorescence and broadband fluorescence upconversion) show that the absorption and emission processes involve strong intramolecular charge transfer between the donor and acceptor substituents via the carborane cluster. From quantum chemical calculations on these carborane systems, the charge transfer process depends on the relative torsional angles of the donor and acceptor groups where an overlap between the two frontier orbitals exists in the bridging carborane cluster.

Self-Assembled Tetraphenylethene-Based Nanoaggregates with Tunable Electrochemiluminescence for the Ultrasensitive Detection of E. coli

As an effective ECL emitter, tetraphenylethene (TPE)-based molecules have recently been reported with aggregation-induced electrochemiluminescence (AIECL) property, while it is still a big challenge to control its aggregation states and obtain uniform aggregates with intense ECL emission. In this study, we develop three TPE derivatives carrying a pyridinium group, an alkyl chain, and a quaternary ammonium group via the Menschutkin reaction. The resulting molecules exhibit significantly red-shifted FL and enhanced ECL emissions due to the tunable reduction of the energy gap between the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs). More importantly, the amphiphilicity of the as-developed molecules enables their spontaneous self-assembly into well-controlled spherical nanoaggregates, and the ECL intensity of nanoaggregates with 3 -CH2- (named as C3) is 17.0-fold higher compared to that of the original 4-(4-(1,2,2-triphenylvinyl)phenyl)pyridine (TPP) molecule. These cationic nanoaggregates demonstrate a high affinity toward bacteria, and an ECL sensor for the profiling of Escherichia coli (E. coli) was developed with a broad linear range and good selectivity in the presence of an E. coli-specific aptamer. This study provides an effective way to enhance the ECL emission of TPE molecules through their derivatization and a simple way to prepare well-controlled AIECL nanoaggregates for ECL application.

Molecular engineering of AIE-active boron clustoluminogens for enhanced boron neutron capture therapy

The development of boron delivery agents bearing an imaging capability is crucial for boron neutron capture therapy (BNCT), yet it has been rarely explored. Here we present a new type of boron delivery agent that integrates aggregation-induced emission (AIE)-active imaging and a carborane cluster for the first time. In doing so, the new boron delivery agents have been rationally designed by incorporating a high boron content unit of a carborane cluster, an erlotinib targeting unit towards lung cancer cells, and a donor-acceptor type AIE unit bearing naphthalimide. The new boron delivery agents demonstrate both excellent AIE properties for imaging purposes and highly selective accumulation in tumors. For example, at a boron delivery agent dose of 15 mg kg-1, the boron amount reaches over 20 μg g-1, and both tumor/blood (T/B) and tumor/normal cell (T/N) ratios reach 20-30 times higher than those required by BNCT. The neutron irradiation experiments demonstrate highly efficient tumor growth suppression without any observable physical tissue damage and abnormal behavior in vivo. This study not only expands the application scopes of both AIE-active molecules and boron clusters, but also provides a new molecular engineering strategy for a deep-penetrating cancer therapeutic protocol based on BNCT.

Ortho-Carborane Decorated Multi-Resonance TADF Emitters: Preserving Local Excited State and High Efficiency in OLEDs

A novel class of o-carboranyl luminophores, 2CB-BuDABNA (1) and 3CB-BuDABNA (2) is reported, in which o-carborane moieties are incorporated at the periphery of the B,N-doped multi-resonance thermally activated delayed fluorescence (MR-TADF) core. Both compounds maintain the inherent local emission characteristics of their MR-emitting core, exhibiting intense MR-TADF with high photoluminescence quantum yields in toluene and rigid states. In contrast, the presence of the dark lowest-energy charge transfer state, induced by cage rotation in THF, is suggested to be responsible for emission quenching in a polar solvent. Despite the different arrangement of the cage on the DABNA core, both 1 and 2 show red-shifted emissions compared to the parent compound BuDABNA (3). By utilizing 1 as the emitter, high-efficiency blue organic light-emitting diodes (OLEDs) are achieved with a remarkable maximum external quantum efficiency of 25%, representing the highest reported efficiency for OLEDs employing an o-carboranyl luminophore as the emitter.

Dual-microRNA-Controlled Electrochemiluminescence Biosensor for Breast Cancer Diagnosis and Supplemental Identification of Breast Cancer Metastasis

Breast cancer remains the most frequently diagnosed cancer globally, and the metastasis of this malignancy is the primary cause of mortality in breast cancer patients. Hence, prompt diagnosis and timely detection of metastatic breast cancer are critical for effective therapeutic intervention. Both progression and metastasis of this malignancy are closely associated with aberrant expression of specific microRNAs (miRNAs) and enzymes. To facilitate breast cancer diagnosis and concomitant identification of metastatic breast cancer, we have engineered an innovative electrochemiluminescence (ECL)-based sensing platform integrated with enzyme-free DNA amplification circuits for dual functionality. Specifically, microRNA-21 (miR-21) is employed as a biomarker for breast cancer, and miR-21 induces the quenching of the ECL signal from luminophores via a strategically designed catalytic three-hairpin assembly (CTHA) circuit. Subsequently, miR-105 levels are measured via toehold-mediated strand displacement reactions (TSDR). Here, miR-105 restores the initially quenched ECL signal, enabling the assessment of the metastatic propensity. Our experimental data demonstrate that the devised ECL biosensor offers broad linear detection ranges and low detection limits for both miR-21 and miR-105. Importantly, our novel platform was also successfully validated by using cellular and serum samples. This biosensor not only discriminates breast cancer cell lines MCF-7 and MDA-MB-231 from nonbreast cancer cells like HepG2, TPC-1, and HeLa, but it also distinguishes between malignant MCF-7 and metastatic MDA-MB-231 cells. Consequently, our novel approach holds significant promise for clinical applications and precise cancer screening.

Palladium-Catalyzed Regioselective B(3,5)-Dialkenylation and B(4)-Alkenylation of o-Carboranes

Picolyl group directed B(3,5)-dialkenylation and B(4)-monoalkenylation of o-carboranes has been developed with a very low palladium catalyst loading. The degree of substitution is determined by the cage C(2)-substituents due to steric reasons. On the basis of experimental results, a plausible mechanism is proposed including electrophilic palladation and alkyne insertion followed by protonation.

Ternary electrochemiluminescence quenching effects of CuFe2O4@PDA-MB towards self-enhanced Ru(dcbpy)32+ functionalized 2D metal-organic layer and application in carcinoembryonic antigen immunosensing

BACKGROUND

Carcinoembryonic antigen (CEA) is a significant glycosylated protein, and the unusual expression of CEA in human serum is used as a tumor marker in the clinical diagnosis of many cancers. Although scientists have reported many ways to detect CEA in recent years, such as electrochemistry, photoelectrochemistry, and fluorescence, their operation is complex and sensitivity is average. Therefore, finding a convenient method to accurately detect CEA is significance for the prevention of malignant tumors. With high sensitivity, quick reaction, and low background, electrochemiluminescence (ECL) has emerged as an essential method for the detection of tumor markers in blood.

RESULTS

In this work, a "signal on-off" ECL immunosensor for sensitive analysis of CEA ground on the ternary extinction effects of CuFe2O4@PDA-MB towards a self-enhanced Ru(dcbpy)32+ functionalized metal-organic layer [(Hf)MOL-Ru-PEI-Pd] was prepared. The high ECL efficiency of (Hf)MOL-Ru-PEI-Pd originated from the dual intramolecular self-catalysis, including intramolecular co-reaction between polyethylenimine (PEI) and Ru(dcbpy)32+. At the same time, loading Pd NPs onto (Hf)MOL-Ru-PEI could not only improve the electron transfer ability of (Hf)MOL-Ru-PEI, but also provide more active sites for the reaction of Ru(dcbpy)32+ and PEI. In the presence of CEA, CuFe2O4@PDA-MB-Ab2 efficiently quenches the excited states of (Hf)MOL-Ru-PEI-Pd by PDA, Cu2+, and methylene blue (MB) via energy and electron transfer, leading to an ECL signal decrease. Under optimal conditions, the proposed CEA sensing strategy showed satisfactory properties ranging from 0.1 pg mL-1 to 100 ng mL-1 with a detection limit of 20 fg mL-1.

SIGNIFICANCE

The (Hf)MOL-Ru-PEI-Pd and CuFe2O4@PDA-MB were prepared in this work might open up innovative directions to synthesize luminescence-functionalized MOLs and effective quencher. Besides, the ECL quenching mechanism of Ru(dcbpy)32+ by MB was successfully explained by the inner filter effect (ECL-IFE). At last, the proposed immunosensor exhibits excellent repeatability, stability, and selectivity, and may provide an attractive way for CEA and other disease markers determination.

Bifunctional TiO2 Nanoflower-Induced H4TCBPE Aggregation Enhanced Electrochemiluminescence for an Ultrasensitive Assay of Organophosphorus

In this work, the aggregation-induced emission ligand 1,1,2,2-tetra(4-carboxylbiphenyl)ethylene (H4TCBPE) was rigidified in the Ti-O network to form novel electrochemiluminescence (ECL) emitter H4TCBPE-TiO2 nanospheres, which acted as an effective ECL emitter to construct an "on-off" ECL biosensor for ultrasensitive detection of malathion (Mal). H4TCBPE-TiO2 exhibited excellent ECL responses due to the Ti-O network that can restrict the intramolecular free motions within H4TCBPE and then reduce the nonradiative relaxation. Moreover, TiO2 can act as an ECL co-reaction accelerator to promote the generation of sulfate radical anion (SO4•-), which interacts with H4TCBPE in the Ti-O network to produce enhanced ECL response. In the presence of Mal, numerous ligated probes (probe 1 to probe 2, P1-P2) were formed and released by copper-free click nucleic acid ligation reaction, which then hybridized with hairpin probe 1 (H1)-modified H4TCBPE-TiO2-based electrode surface. The P1-P2 probes can initiate the target-assisted terminal deoxynucleoside transferase (TdTase) extended reaction to produce long tails of deoxyadenine with abundant biotin, which can load numerous streptavidin-functionalized ferrocenedicarboxylic acid polymer (SA-PFc), causing quenching of the ECL signal. Thus, the ultrasensitive ECL biosensor based on H4TCBPE-TiO2 ECL emitter and click chemistry-actuated TdTase amplification strategy presents a desirable range from 0.001 to 100 ng/mL and a detection limit low to 9.9 fg/mL. Overall, this work has paved an avenue for the development of novel ECL emitters, which has opened up new prospects for ECL biosensing.

Advances of Electrochemical and Electrochemiluminescent Sensors Based on Covalent Organic Frameworks

Covalent organic frameworks (COFs), a rapidly developing category of crystalline conjugated organic polymers, possess highly ordered structures, large specific surface areas, stable chemical properties, and tunable pore microenvironments. Since the first report of boroxine/boronate ester-linked COFs in 2005, COFs have rapidly gained popularity, showing important application prospects in various fields, such as sensing, catalysis, separation, and energy storage. Among them, COFs-based electrochemical (EC) sensors with upgraded analytical performance are arousing extensive interest. In this review, therefore, we summarize the basic properties and the general synthesis methods of COFs used in the field of electroanalytical chemistry, with special emphasis on their usages in the fabrication of chemical sensors, ions sensors, immunosensors, and aptasensors. Notably, the emerged COFs in the electrochemiluminescence (ECL) realm are thoroughly covered along with their preliminary applications. Additionally, final conclusions on state-of-the-art COFs are provided in terms of EC and ECL sensors, as well as challenges and prospects for extending and improving the research and applications of COFs in electroanalytical chemistry.

Aggregation-induced electrochemiluminescence enhancement of Ag-MOG for amyloid β 42 sensing

This study aimed to introduce an immunosensor for measuring amyloid β 42 (Aβ42) levels by aggregation-induced enhanced electrochemiluminescence (ECL). Metal-organic gels (MOGs) are novel soft materials with advantages such as high gel stability, good light-emitting properties, and easy preparation. This study used silver nanoparticle metal-organic gel (Ag-MOG) as a substrate to connect Aβ42-Ab2 and the cathodoluminescent probe. Potassium persulfate was used as a co-reactant that could emit a high ECL signal. CuS@Au had the benefits of a relatively large surface area with excellent carrier function; therefore, it was used as a substrate to load a large amount of Aβ42-Ab1, significantly improving the immunosensor sensitivity. The ECL intensity of Aβ42 was linear in the range of 0.01 pg/mL to 250 ng/mL with a detection limit of 2.2 fg/mL (S/N = 3) under optimized detection conditions. This ECL immunosensor has been successfully applied to detect Aβ42 in human serum with the advantages of excellent stability and high selectivity. This method not only expands the potential applications of ECL immunosensors based on biological testing and clinical diagnosis but also provides a viable approach to basic clinical testing.

Reaction of 4-Bpin-o-Carborane with Ketones: Sequential Carbon Vertex Alkylation and B-B Bond Activation

Diboron compounds are important reagents in a series of transition metal catalyzed or metal-free borylation reactions. We describe herein a unique reactivity of 4-Bpin-o-carborane with ketones under basic conditions, leading to sequential cage carbon alkylation, B-B bond activation and unexpected O-migration. The reaction was compatible with a good substrate scope including dialkyl or alkyl aryl ketones. The reaction mechanism is also proposed, involving cage CH deprotonation, nucleophilic attack of ketone, and O-migration along with B-B bond cleavage.

Facile preparation of poly-(styrene-co-maleic anhydride) encapsulated Iridium(III) complexes as highly efficient electrochemiluminescence indicators for sensitive immunoassay of CYFRA 21-1

Exploring facile strategy for developing highly efficient emitters using water-insoluble luminophores has become a vital topic in electrochemiluminescence (ECL) immunoassay. In this work, an ECL-active and water-dispersive iridium(III) complex-based polymer dots (IrPdots) was fabricated by encapsulating water-insoluble tris[1-phenylisoquinolinato-C2, N] iridium(III) complexes [Ir(piq)₃] into poly-(styrene-co-maleic anhydride) (PSMA) matrix by a controllable nanoprecipitation process. The obtained IrPdots generated strong ECL signals in the presence of tri-n-propylamine (TPrA) and were used to label detection antibody (Ab₂) to act as ECL probes to indicate the signal changes when analyzing target antigen. To construct a sandwich immunosensor, Pd nanoparticles (NPs) decorated MoS₂/Ti₃C₂T_x MXene nanocomposites (MoS₂/Ti₃C₂T_x MXene/Pd) were fabricated as substrates to bind capture antibody (Ab₁), which could further amplify ECL signals via a coreaction-accelerating pathway to improve the detection sensitivity. When the cytokeratin 19 fragment 21-1 (CYFRA 21-1) was chosen as model analyte, the developed immunosensor displayed a good linear relationship ranging from 0.1 pg/mL to 50 ng/mL with a low detection limit of 95 fg/mL (S/N = 3) was achieved as well. This research proposed a facile and effective method of fabricating IrPdots as ECL probes for immunoassay using water-insoluble iridium complexes, which expanded the application scope of those water-insoluble luminophores for aqueous bioanalysis.

Materials for Electrochemiluminescence: TADF, Hydrogen-Bonding, and Aggregation- and Crystallization-Induced Emission Luminophores

Electrochemiluminescence (ECL) is a rapidly growing discipline with many analytical applications from immunoassays to single-molecule detection. At the forefront of ECL research is materials chemistry, which looks at engineering new materials and compounds exhibiting enhanced ECL efficiencies compared to conventional fluorescent materials. In this review, we summarize recent molecular design strategies that lead to high efficiency ECL. In particular, we feature recent advances in the use of thermally activated delayed fluorescence (TADF) emitters to produce enhanced electrochemiluminescence. We also document how hydrogen bonding, aggregation, and crystallization can each be recruited in the design of materials showing enhanced electrochemiluminescence.

Iridium(III)-Catalyzed Regioselective B(4)-H Amination of o-Carboranes with Sufilimines

Iridium(III)-catalyzed regioselective B(4)-H amination is developed from the reaction of o-carborane acids with sulfilimines without any oxidants under mild conditions, which leads to a wide range of B(4)-H aminated o-carboranes in good yields with a broad substrate scope. Moreover, the selective B(3,6)-diamination reaction of the o-carborane acid was achieved. The present reaction is attractive from a practical point of view because dibenzothiophene is quantitatively recovered and reused.

Charge Transfer Complex-Enabled Synthesis of (Hetero)arylated m-Carboranes from m-Carborane Phosphonium Salts

A photoinduced charge transfer complex (CTC)-enabled photoreduction of carborane phosphonium salts for the cage carbon (hetero)arylation of carboranes was developed. It offers a convenient approach for introducing a wide range of aryl and heteroaryl groups, such as pyrroles, thiophenes, indoles, thianaphthenes, benzofurans, pyridines, and benzenes, into carboranes. This strategy offers operational simplicity, mild reaction conditions, and a broad substrate scope, making it highly advantageous.

Impact of the metal core on the electrochemiluminescence of a pair of atomically precise Au20 nanocluster isomers

Although the electrochemiluminescence (ECL) of metal nanoclusters has been reported, revealing the correlation between structure and ECL at an atomic level is highly challenging. Here, we reported the impact of the metal core of Au₂₀(SAdm)₁₂(CHT)₄ (Au₂₀-AC for short; SAdm = 1-adamantanethiolate; CHT= cyclohexanethiol) and its isomer Au₂₀(TBBT)₁₆ (TBBT = 4-tert-butylthiophenol) on their solution-state and solid-state electrochemiluminescence. In self-annihilation ECL experiments, Au₂₀-AC showed a strong cathodic ECL but a weak anodic ECL, while the ECL signal of Au₂₀(TBBT)₁₆ was weak and barely detectable. Density functional theory (DFT) calculations showed that the Au₇ kernel of [Au₂₀-AC]^- is metastable, weakening its anodic ECL. Au₂₀-AC in solution-state displayed an intense co-reactant ECL in the near-infrared region, which is 7 times higher than that of standard Ru(bpy)₃²⁺. The strongest solid-state ECL emissions of Au₂₀-AC and Au₂₀(TBBT)₁₆ were at 860 and 770 nm, respectively - 15 nm red-shifted for Au₂₀-AC and 20 nm blue-shifted for Au₂₀(TBBT)₁₆, compared to their corresponding solid-state photoluminescence (PL) emissions. This work shows that ECL is significantly affected by the subtle differences of the metal core, and offers a potential basis for sensing and immunoassay platforms based on atomically precise emissive metal nanoclusters.

High-Contrast Visualization Chemiluminescence Based on AIE-Active and Base-Sensitive Emitters

Peroxyoxalate chemiluminescence (PO-CL) is one of the most popular cold light sources, yet the drawback of aggregation-caused quenching limits their use. Here, we report a new kind of efficient bifunctional emitter derived from salicylic acid, which not only exhibits typical aggregation-induced emission (AIE) character but also has the ability to catalyze the CL process under basic conditions based on base sensitivity. By taking advantage of these unique features, we successfully confine the CL process on the surface of solid bases and provide a high-contrast visualization of CL emission. This method allows most of the common basic salts like sodium carbonate to be invisible encryption information ink and PO-CL solution to be a decryption tool to visualize the hidden information. The current study opens up an appealing way for the development of multifunction CL emitters for information encryption and decryption applications.

Dual-quenching mechanisms in electrochemiluminescence immunoassay based on zinc-based MOFs of ruthenium hybrid for D-dimer detection

The successful application of electrochemiluminescence (ECL) in immunoassay for clinical diagnosis requires improving sensitivity and accuracy. Herein was reported an ECL analytical model based zinc-based metal-organic frameworks of ruthenium hybrid (RuZn MOFs) as the signal emitter. To enlarge the output difference, the quenching effect of three different noble metal nanoparticles included palladium seeds (Pd_seeds), palladium octahedrons (Pd_oct), and Pt-based palladium (Pd@Pt_oct) core-shell were researched. Among them, Pd@Pt_oct core-shell possessed higher activity and improved durability than Pd-only (NPs), they could load more protein macromolecules amicably and stabilized in the analysis system. Furthermore, since the charge redistribution owing to the hybridization of the Pt and Pd atoms in Pd@Pt_oct, it could generate the electron flow maximumly from the emitter RuZn MOFs to Pd@Pt_oct and result in the enhancement of quenching ECL. And the UV absorption of noble metal nanoparticles overlapped with the ECL emission of RuZn MOFs to varying degrees, which caused the behavior of resonance energy transfer (RET) reaction at the same time. This would greatly promote the sensitivity of this ECL system compared with the traditional single quenching mechanism. Based on this, a signal-off immunsensor was constructed to sensitive detection of D-dimer with linearity range from 0.001 to 200 ng mL^-1, limit of detection (LOD) was 0.20 pg mL^-1 and provide a further theoretical basis for the clinical application of ECL technology.

Aggregation-Induced Electrochemiluminescence Based on a Zinc-Based Metal-Organic Framework and a Double Quencher Au@UiO-66-NH2 for the Sensitive Detection of Amyloid β 42 via Resonance Energy Transfer

A novel sandwich electrochemiluminescence (ECL) biosensor based on aggregation-induced electrochemiluminescence resonance energy transfer (AIECL-RET) was designed for the sensitive detection of amyloid β42 (Aβ42). The synthesized silver nanoparticle-functionalized zinc metal-organic framework (Ag@ZnPTC) and gold nanoparticle-functionalized zirconium organic framework (Au@UiO-66-NH₂) were used as the ECL donor and acceptor, respectively. AgNPs were generated in situ on the surface of ZnPTC, which further improved the ECL intensity and the loading of antibody 1 (Ab1). Under the optimized experimental conditions, the linear detection range of Aβ42 concentration was 10 fg/mL to 100 ng/mL, and the detection limit was 2.4 fg/mL (S/N = 3). The recoveries of Aβ42 were 99.5-104%. The method has good stability, repeatability, and specificity. Ag@ZnPTC/Au@UiO-66-NH₂ provides an assay for the sensitive detection of disease biomarkers.

B(9)-OH-o-Carboranes: Synthesis, Mechanism, and Property Exploration

Herein, we present a chemically robust and efficient synthesis route for B(9)-OH-o-carboranes by the oxidation of o-carboranes with commercially available 68% HNO₃ under the assistance of trifluoromethanesulfonic acid (HOTf) and hexafluoroisopropanol (HFIP). The reaction is highly efficient with a wide scope of carboranes, and the selectivity of B(9)/B(8) is up to 98:2. The success of this transformation relies on the strong electrophilicity and oxidizability of HNO₃, promoted through hydrogen bonds of the Brønsted acid HOTf and the solvent HFIP. Mechanism studies reveal that the oxidation of o-carborane involves an initial electrophilic attack of HNO₃ to the hydrogen atom at the most electronegative B(9) of o-carborane. In this transformation, the hydrogen atom of the B-H bond is the nucleophilic site, which is different from the electrophilic substitution reaction, where the boron atom is the nucleophilic site. Therefore, this is an oxidation-reduction reaction of o-carborane under mild conditions in which N(V) → N(III) and H(-I) → H(I). The derivatization of 9-OH-o-carborane was further examined, and the carboranyl group was successfully introduced to an amino acid, polyethylene glycol, biotin, deoxyuridine, and saccharide. Undoubtedly, this approach provides a selective way for the rapid incorporation of carborane moieties into small molecules for application in boron neutron capture therapy, which requires the targeted delivery of boron-rich groups.

Aggregation-Induced Electrochemiluminescence and Nitric Oxide Recognition by Halogen Bonding with a Ruthenium(II) Complex

In this study, a new strategy for NO detection based on the aggregation-induced electrochemical luminescence (AIECL) of a ruthenium-based complex and the halogen bonding effect was developed. First, [Ru(phen)₂ (phen-Br₂ )]²⁺ (phen : 1,10-phenanthroline, phen-Br₂  : 3,8-dibromo-1,10-phenanthroline) was synthesized and exhibited aggregation-induced emission (AIE) and AIECL properties in a poor solvent (H₂ O). [Ru(phen)₂ (phen-Br₂ )]²⁺ exhibited greatly enhanced AIECL properties compared to its AIE intensity. When the volume fraction of water (f_w , v %) in the H₂ O-acetonitrile (MeCN) system was increased from 30 to 90 %, the photoluminescence and electrochemiluminescence (ECL) intensities were three- and 800-fold that of the pure MeCN system, respectively. Dynamic light scattering and scanning electron microscopy results indicated that [Ru(phen)₂ (phen-Br₂ )]²⁺ aggregated into nanoparticles. AIECL is sensitive to NO because of its halogen bonding effect. The C-Br⋅⋅⋅N bond between [Ru(phen)₂ (phen-Br₂ )]²⁺ and NO increased the distance of complex molecules, resulting in ECL quenching. A detection limit of 2 nM was obtained with 5 orders of magnitude linear range. The combination of the AIECL system and the halogen bond effect expands the theoretical research and applications in biomolecular detection, molecular sensors, and stages of medical diagnosis.

Advances in electrochemiluminescence luminophores based on small organic molecules for biosensing

Electrochemiluminescence (ECL) has several advantages, such as a near-zero background signal, high sensitivity, wide dynamic range, simplicity, and is widely used for sensing, imaging, and single cell analysis. ECL luminophores are the key factors in the performance of various applications. Among various luminophores, small organic luminophores exhibit many intriguing features including good biocompatibility, facile modification, well-defined molecular structure, and sustainable raw materials, making small organic luminophores attractive for the use in the ECL field. Although many great achievements have been made in the synthesis of new small organic luminophores, solving various challenges, and expanding new applications, there are almost no comprehensive reviews on small organic ECL luminophores. In this review, we briefly introduce the advantages and emission mechanisms of small organic ECL luminophores, summarize the main types, molecular characteristics, and ECL properties of most existing small organic ECL luminophores, and present the important applications and design principles in sensors, imaging, single cell analysis, sterilization, and other fields. Finally, the challenges and outlook of organic ECL luminophores to be popularized in biosensing applications are also discussed.

Hexagon AgNCs/PVP Crystallization Induced Cathode Electrochemiluminescence Enhancement for miRNA221 Biosensing

Aggredation-induced electrochemiluminescence (AIECL) promises an efficient strategy for synthesize highly luminescent emitter and co-reactant for ECL analysis, however, rational control of electrogenerated emission intensity is still challenging. The low electroconductivity and amorphous molecular configuration are intrinsic bottleneck. This work reveals the impact of polyvinyl pyrrolidone backbone regulated silver nanocrystallines (AgNCs/PVP) on the cathode AIECL properties in near infrared region, by employing the Box-Behnken designed response surface computation model to modulate crystal aggregates. Electron paramagnetic resonance spectroscopy discovered hydrogen radical (HO^• ) dominant reductive-oxidative (R-O) ECL mechanism with AgNCs acting as the co-reaction accelerator in graphene oxide/persulfate system (GO/S₂ O₈ ^2- ). Both theoretical calculation and experimental measurement testified that the ECL of AgNCs in GO/S₂ O₈ ^2- dependent on the concentration of in situ electrochemical oxidized Ag⁺ . The high efficiency of crystallization-induced enhanced ECL (CIECL) originates from 1) the effective electron transfer of Ag⁺ accelerated HO^• produce to notable promote radioactive transition, and 2) twisted intramolecular charge transfer from the electron-rich donor of PVP to electron-deficient receptor of Ag⁰ to restrict nonradioactive transition. The AgNCs/PVP with CIECL effect are applied to construct an ultrasensitive platform for miR-221 assay with a lower detection limit of 7.47 × 10³  copies mL^-1 than typical qPCR method.

Iridium-catalyzed regioselective B(3,6)-dialkenylation or B(4)-alkenylation of o-carboranes via B-H activation and 1,2-carbon migration of alkynes

An efficient Ir-catalyzed cage boron alkenylation of 1-(2'-picolyl)-o-carboranes with diarylacetylenes has been developed, leading to a wide variety of B-H geminal addition products via 1,2-carbon migration of alkynes. The steric effect of cage carbon substituents has a great impact on the regioselectivity of such alkenylation reactions.

A Method for Highly Selective Halogenation of o-Carboranes and m-Carboranes

A facile halogenation method for highly selective synthesis of 9-X-o-carboranes, 9,12-X₂-o-carboranes, 9-X-12-X'-o-carboranes, 9-X-m-carboranes, 9,10-X₂-m-carboranes, and 9-X-10-X'-m-carboranes (X, X' = Cl, Br, I) has been developed on the basis of our previous work. The success of this transformation relies on the usage of trifluoromethanesulfonic acid (HOTf), the easily available strong Brønsted acid. The addition of HOTf greatly increases the electrophilicity of N-haloamides through hydrogen bonding interaction, resulting in the low loading of N-haloamides, short reaction time, and mild reaction conditions. Additionally, the solvent 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) is also essential to further increase the acidity of HOTf.

Voltammetric Study and Modeling of the Electrochemical Oxidation Process and the Adsorption Effects of Luminol and Luminol Derivatives on Glassy Carbon Electrodes

Luminol is one of the most widely used electrochemiluminescence (ECL) reagents, yet the detailed mechanism and kinetics of the electrochemical oxidation of luminol remain unclear. We propose a model that describes the electrochemical oxidation of luminol as multiple electron transfer reactions followed by an irreversible chemical reaction, and we applied a finite element method simulation to analyze the electron transfer kinetics in alkaline solutions. Although negligible at higher pH values, the adsorption of luminol on the glassy carbon electrode became noticeable in a solution with pH = 12. Additionally, various types of adsorption behaviors were observed for luminol derivatives and analogues, indicating that the molecular structure affected not only the oxidation but also the adsorption process. The adsorption effect was analyzed through a model with a Langmuir isotherm to show that the saturated surface concentration as well as the reaction kinetics increased with decreasing pH, suggesting a competition for the active sites between the molecule and OH^-. Moreover, we show that the ECL intensity could be boosted through the adsorption effect by collecting the ECL intensity generated through the electrochemical oxidation of luminol and a luminol analogue, L012, in a solution with pH = 13. In contrast with luminol, a significant adsorption effect was observed for L012 at pH = 13, and the ECL intensity was enhanced by the adsorbed species, especially at higher scan rates. The magnitude of the enhancement of the ECL intensity matched well with the simulation using our model.

Study on the Electrochemiluminescence of Pentaphenylpyrrole in the Aqueous Phase Based on Structure-Regulated Strategy

Heterocyclic nitrogen compounds play a vital role in luminescent materials, but most of them face the challenges of aggregation-caused quenching (ACQ) and poor water solubility. In this work, we present the nitrogen heterocyclic pentaphenylpyrrole (PentaPP) with an excellent aggregation-induced electrochemiluminescence (AIE-ECL) performance in the aqueous phase through the comparison of the elegant ECL luminophore 5,10,15,20-tetraphenylporphyrin (TPP). Further studies suggest that such unique AIE-ECL arises from its propeller-like noncoplanar structure and the large conjugation from the phenyl groups on the ring. In addition, the new ECL analysis could feature some advantages of AIE characteristic, water compatibility, and strong signal and finally achieve the ultrasensitive detection toward the explosive 2,4,6-trinitrophenol (TNP) with a lower detection limit (1.1 nM). This study does not only benefit to solve the two key problems mentioned before but also enriches the fundamentals and applications for ECL and pyrrole research.

Studies on Annihilation and Coreactant Electrochemiluminescence of Thermally Activated Delayed Fluorescent Molecules in Organic Medium

Very recently, there is a great research interest in electrochemiluminescence (ECL) featuring thermally activated delayed fluorescence (TADF) properties, i.e., TADF-ECL. It is appealing since the earlier reports in this topic well-confirmed that this strategy has a great potential in achieving all-exciton-harvesting ECL efficiency under electrochemical excitation, which is a breakthrough in the topic of organic ECL. However, organic phase electrochemistry and ECL studies surrounding TADF-ECL are still extremely rare. Especially, the ECL spectra of previous reported TADF emitters are still very different from their PL spectra. In this work, we systematically measure and discuss the liquid electrochemistry and ECL behavior of two typical TADF molecules in organic medium. Most importantly, we verify for the first time that the ECL spectra of them (coreactant ECL mode) are identical to their PL spectra counterparts, which confirms the effectiveness of TADF photophysical properties in the coreactant ECL mode in practice.

Electrochemiluminescence resonance energy transfer biosensing platform between g-C3N4 nanosheet and Ru-SiO2@FA for dual-wavelength ratiometric detection of SARS-CoV-2 RdRp gene

Rational detection of syndrome coronavirus 2 (SARS-CoV-2) is crucial to prevention, control, and treatment of disease. Herein, a dual-wavelength ratiometric electrochemiluminescence (ECL) biosensor based on resonance energy transfer (RET) between g-C₃N₄ nanosheets and Ru-SiO₂@folic acid (FA) nanomaterials was designed to realize ultrasensitive detection of SARS-CoV-2 virus (RdRp gene). Firstly, the unique g-C₃N₄ nanosheets displayed very intense and stable ECL at 460 nm, then the triple helix DNA was stably and vertically bound to g-C₃N₄ on electrode by high binding affinity between ssDNA and g-C₃N₄. Meanwhile, trace amounts of target genes were converted to a large number of output by three-dimensional (3D) DNA walker multiple amplification, and the output bridged a multifunctional probe Ru-SiO₂@FA to electrode. Ru-SiO₂@FA not only showed high ECL at 620 nm, but also effectively quenched g-C₃N₄ ECL. As a result, ECL decreased at 460 nm and increased at 620 nm, which was used to design a rational ECL biosensor for detection of SARS gene. The results show that the biosensor has excellent detection sensitivity for RdRp gene with a dynamic detection range of 1 fM to 10 nM and a limit of detection (LOD) of 0.18 fM. The dual-wavelength ratio ECL biosensor has inestimable value and application prospects in the fields of biosensing and clinical diagnosis.

Rigid Enhanced Electrochemiluminescence of 1,2,3-Triaryl Indenes as an Ultrasensitive Sensor for D2O in H2O

The intriguing aggregation-induced emission has recently been applied in the electrochemiluminescence, called aggregation-induced electrochemiluminescence (AIE-ECL), which is conducive to solving the water insolubility and aggregation-caused quenching for most organic luminescence probes. However, AIE-ECL still has the problems of low luminous efficiency and limited practical application. In this work, we disclosed the AIE-ECL properties of 1,2,3-triaryl-substituted indenes containing rigid structures. Experimental and theoretical investigations demonstrated that such a rigid structure could significantly enhance the aromaticity and stability and thereby the luminescence performance of these indenes. Moreover, according to the finding of hydrogen/deuterium exchange for active hydrogen in indene under electrical excitation, ultrasensitive detection for D₂O in H₂O was realized by such an indene-based AIE-ECL system. Our research not only provided an attractive strategy to enhance the luminescence property for an AIE-active luminophore but also established a superior sensor toward D₂O.

Construction of an aggregation-induced electrochemiluminescent sensor based on an aminal-linked covalent organic framework for sensitive detection of glutathione in human serum

We demonstrate the construction of an aggregation-induced electrochemiluminescent (AIECL) sensor for glutathione (GSH) assay by integrating an aminal-linked covalent organic framework (A-COF) with manganese dioxide (MnO₂) nanosheets. The AIECL of the A-COF is quenched by the MnO₂ nanosheets via electrochemiluminescent resonance energy transfer (ERET) from the excited A-COF to MnO₂. The presence of GSH can reduce the MnO₂ nanosheets into Mn²⁺, restoring the AIECL emission of the A-COF. This AIECL sensor has the characteristics of fast response, high sensitivity, and good selectivity toward GSH, and it can accurately measure GSH in human serum.

Highly Efficient Aggregation-Induced Electrochemiluminescence of Al(III)-Cbatpy Metal-Organic Gels Obtained by Ultrarapid Self-Assembly for a Biosensing Application

Aggregation-induced electrochemiluminescence (AIECL) has attracted extensive interest due to the significant increase in ECL response by restricting free intramolecular rotation and torsion, but traditional AIECL emitters suffer from limited ECL efficiency, high cost, and complex synthetic steps, dramatically limiting their applications. Herein, novel Al(III)-Cbatpy metal-organic gels (Al(III)-Cbatpy-MOGs) with nanofiber morphology and ultrarapid coordination of Al³⁺ and 4'-carboxylic acid-2,2':6',2″-terpyridine (Cbatpy) are developed, which demonstrates an excellent AIECL enhancement behavior far beyond that reported in ECL supramolecular gels. In view of the strong affinity of N and O atoms in Cbatpy toward Al³⁺, Al(III)-Cbatpy-MOGs with high viscosity and stability can be assembled in one step within about 15 s, easily conquering the main predicaments of current AIECL emitters: complicated synthesis steps and poor film formation. Impressively, the ECL efficiency of Al(III)-Cbatpy-MOGs with superemission is about 20 times higher than that of individual Cbatpy molecules, which is attributed to the aggregation of the organic ligand Cbatpy restricting intramolecular rotation and torsion to reduce nonradiative relaxation. Furthermore, compared with traditional metal complexes, Al(III)-Cbatpy-MOGs show the benefits of remarkable biocompatibility and low cost without the involvement of any organic solvents, noble metals, and rare metals. As proof, a "signal-off" sensing platform based on an Al(III)-Cbatpy-MOGs/S₂O₈^2- system was constructed for the sensitive detection of dopamine (DA) with a low detection limit of 0.34 nM. This strategy provides a novel method to prepare cheap metal-organic gels as a highly efficient AIECL emitter, which is promising as a luminescent molecular device and biosensor for clinical diagnostic applications.

Two 1D Anderson-Type Polyoxometalate-Based Metal-Organic Complexes as Bifunctional Heterogeneous Catalysts for CO2 Photoreduction and Sulfur Oxidation

Sulfur oxides from the combustion of petrol and excessive emissions of carbon dioxide (CO₂) are currently the main causes of environmental pollution. Considerable interest has been paid to solving the challenge, and catalytic reactions seem to be the desired choice. Due to the high density of Lewis acid active sites, polyoxometalates are considered to be the ideal choice for these catalytic reactions. Herein, two captivating polyoxometalate-based metal-organic complexes, formulated as [Co(H₂O)₂DABT]₂[CrMo₆(OH)₅O₁₉] ({Co-CrMo₆}) and [Zn(H₂O)₂DABT]₂[CrMo₆(OH)₅O₁₉] ({Zn-CrMo₆}) (DABT = 3,3'-diamino-5,5'-bis(1H-1,2,4-triazole)) were successfully obtained under hydrothermal conditions. The structural analysis demonstrates that {Co-CrMo₆} and {Zn-CrMo₆} are isostructural with two different transition metal (Co/Zn) ions based on quadridentate Anderson-type [CrMo₆(OH)₅O₁₉]^4- polyanions. A fan-shaped unit of {Co-CrMo₆}/{Zn-CrMo₆} is linked to generate a one-dimensional (1D) ladder-like structure. Intriguingly, benefitting from rich Co centers with a suitable energy band structure, {Co-CrMo₆} displays better photocatalytic activity than {Zn-CrMo₆} for converting CO₂ into CO, endowing the CO formation of 1935.3 μmol g^-1 h^-1 with high selectivity. Meanwhile, {Co-CrMo₆} also exhibits a satisfactory removal rate of 99% for oxidizing dibenzothiophene at 50 °C, which suggests that {Co-CrMo₆} may be utilized as a potential dual functional material with immense prospects in photocatalytic CO₂ reduction and sulfur oxidation for the first time.

Polythionine-mediated AgNWs-AuNPs aggregation conductive network: Fabrication of molecularly imprinted electrochemiluminescence sensors for selective capture of kanamycin

A molecularly imprinted electrochemiluminescence (ECL) sensor was developed for the specific detection of kanamycin in food using silver nanowires-gold nanoparticles (AgNWs-AuNPs) as a luminophore. Polythionine (pThi), another key component of the luminescent layer, can be used as an accelerator of the coreactant and can promote the formation of the AgNWs-AuNPs conductive network. In addition, molecularly imprinted polymers (MIPs) were polymerized on the AgNWs-AuNPs/pThi conductive network, which laid the foundation for the specific capture of kanamycin. The preparation and testing conditions of the sensor were optimized, and the performance was characterized. Under optimal conditions, the ECL intensity of AgNWs-AuNPs/pThi/MIP/GCE showed a good linear relationship (R² = 0.9956) with kanamycin concentration (1 × 10^-10-1 × 10^-6 M) and a low detection limit (3.14 × 10^-11 M, S/N = 3), showing satisfactory selectivity and stability. As proof, AgNWs-AuNPs/pThi/MIP/GCE was successfully used to detect kanamycin in actual samples with satisfactory recovery (83.27-94.13%), which was in good agreement with the results of HPLC-MS/MS (82.26-95.82%). The successful preparation of AgNWs-AuNPs/pThi/MIP/GCE in this experiment provided a new pathway for designing ECL components and constructing an ultrasensitive sensing platform in the field of hazardous substance detection.

Carboranes in drug discovery, chemical biology and molecular imaging

There exists a paucity of structural innovation and limited molecular diversity associated with molecular frameworks in drug discovery and biomolecular imaging/chemical probe design. The discovery and exploitation of new molecular entities for medical and biological applications will necessarily involve voyaging into previously unexplored regions of chemical space. Boron clusters, notably the carboranes, offer an alternative to conventional (poly)cyclic organic frameworks that may address some of the limitations associated with the use of novel molecular frameworks in chemical biology or medicine. The high thermal stability, unique 3D structure and aromaticity, kinetic inertness to metabolism and ability to engage in unusual types of intermolecular interactions, such as dihydrogen bonds, with biological receptors make carboranes exquisite frameworks in the design of probes for chemical biology, novel drug candidates and biomolecular imaging agents. This Review highlights the key developments of carborane derivatives made over the last decade as new design tools in medicinal chemistry and chemical biology, showcasing the versatility of this unique family of boron compounds.