Magic-sized semiconductor clusters (MSCs) synthesized in organic solvents typically exhibit poor compatibility with aqueous media, which hampers electron transfer and leads to weak electrochemiluminescence (ECL), thereby limiting their biological and environmental applications. Here we report that cation-induced assembly confers aqueous stability on Cd15Se12 MSCs and simultaneously boosts their ECL efficiency. Using cysteine (Cys) as a stabilizing ligand, we prepared water-dispersible Cd15Se12-Cys MSCs and introduced multivalent metal cations (Mn+=Zn2+, Cd2+, K+, Na+, Al3+) to electrostatically bind the surface carboxylate groups, thereby driving spontaneous intercluster assembly. The assembled Cd15Se12-Cys-Mn+ MSCs exhibited a 10-fold enhancement in ECL intensity compared to unassembled counterparts, along with excellent signal stability over 1000 s of continuous operation. Mechanistic studies revealed that the cation valence critically dictates the assembly mode and ECL efficiency. Notably, Zn2+-modified assemblies functioned as highly efficient ECL emitters in a biosensing platform, enabling sensitive lactate detection in sweat with a broad linear range (0.01-50 mM). This work establishes cation-induced assembly as a general strategy to achieve aqueous-stable MSCs with enhanced ECL performance, opening new opportunities for their application in biosensing and environmental monitoring.

Electrogenerated chemiluminescence (ECL) imaging has emerged as a powerful visual analytical technique that integrates electrochemistry and optical detection, and finds extensive applications in immunosensing, single-cell analysis, and single-particle behavior investigation. Its exceptional capacity to realize in situ visual observation of microscale targets endows this method with irreplaceable practical value in frontier analytical research. Luminophores act as the core determinant of ECL imaging emission, while the limited types and inherent defects of conventional luminous materials severely restrict the further development and practical application of ECL imaging. As a newly developed class of functional materials, nanoclusters offer outstanding advantages, including low toxicity, good biocompatibility, tunable optical performance, and high structural uniformity, making them promising innovative luminophores for advanced ECL imaging. This review systematically summarizes the basic equipment of ECL imaging and comprehensively discusses the advantages and limitations of mainstream ECL luminophores. More importantly, it emphatically reviews the unique properties, photon emission-enhancing strategies, and diversified imaging applications of nanocluster-based ECL systems. Additionally, the current technical bottlenecks of nanocluster ECL imaging are discussed, and future research directions, including structure-activity relationship exploration, synergistic performance modification, application expansion, and intelligent equipment integration, are prospected. This review aims to provide a systematic and insightful reference for the rational design of high-efficiency ECL luminophores and the development of novel high-performance ECL imaging platforms for bioanalysis and environmental monitoring.

Food safety concerns are becoming increasingly critical, as trace contaminants such as antibiotic and pesticide residues, illicit additives, synthetic colorants, and heavy metal pollutants pose significant risks to human health. Developing rapid, sensitive, and cost-effective strategies for detecting these substances in complex food matrices has therefore become a pressing challenge in food safety monitoring. This review specifically focuses on food contaminants, including antibiotic and pesticide residues, illegal additives, synthetic colorants, and heavy-metal pollutants—that directly threaten food safety. Surface-enhanced Raman scattering (SERS), with its molecular fingerprinting capability and ultrahigh sensitivity, is widely regarded as a promising technique for this purpose. Nevertheless, the practical deployment of noble-metal substrates has been limited by high cost, poor stability, and reproducibility issues. In response, non-noble-metal SERS substrates have recently attracted substantial attention as viable alternatives. Their enhancement is dominated by chemical mechanisms (CM), where charge transfer (CT), defect-state modulation, and heterostructure coupling act synergistically to achieve signal amplification. Representative materials, including metal oxides, transition-metal chalcogenides, carbon-based systems, and emerging two-dimensional or hybrid structures, have exhibited distinct advantages in the trace detection of diverse food contaminants. This review systematically summarizes enhancement mechanisms, material categories, performance-optimization strategies, and recent advances in the field. It further highlights current challenges related to quantitative mechanistic understanding, substrate stability, matrix interference, and lack of standardized protocols. Finally, future directions are outlined, focusing on theory-guided material design, innovations in multimodal detection, and the development of portable sensing platforms, thereby offering systematic reference and scientific guidance for both fundamental research and practical translation.

A novel dendritic DNA-quantum dot (QD) electrochemiluminescence (ECL) probe was developed and an ECL biosensor constructed for sensitive detection of Hg2+ in water samples by combining with enzyme-assisted multiple cycle amplification strategy. Firstly, the Y-shaped structure was formed based on the Hg2+-induced enzymatic cycle amplification technique, which improved the cutting efficiency and realized the double-amplified DNA product. Moreover, a unique dendritic DNA nanostructure loading numerous QDs was constructed, which can greatly amplify the ECL signal. After the dendritic DNA signal probe was connected to the CNT/gold nanocomposites/electrode by DNA products, the ECL biosensor was constructed for sensitive detection of Hg2+. The proposed dendritic DNA probe opens new ECL application of quantum dots. The smart design of Y-structure coupled with multiple amplification strategy greatly improves detection accuracy and sensitivity; thus, the biosensor not only can detect Hg2+ in water samples, but also has a good application prospect for other targets in environmental analysis.

Precise design of porous electrocatalysts remains a major challenge for efficient energy conversion. Here, guided by finite element simulations (FES), we have revealed that ordered mesoporous frameworks stabilized gas-liquid-solid interfaces by promoting uniform gas distribution and nanoscale liquid films on hydrophilic surfaces, enhancing mass transfer kinetics. Based on these insights, we developed a superlattice (SL) imprinting method to construct robust three-dimensional (3D) ordered mesoporous carbon (OMC) frameworks embedded with atomically dispersed Ni single atoms. This method integrated confined oxidation for thermal stabilization, ligand-carbonization to preserve SL-derived porosity, acid etching to improve hydrophilicity, hightemperature graphitization for conductivity, and in situ heteroatom doping to optimize Ni coordination. The resulting Ni-N2S2 and Ni-N3P catalysts exhibited excellent electrocatalytic activity, achieving overpotentials of 239 mV [oxygen evolution reaction (OER): 20 mA cm-2] and 90 mV [hydrogen evolution reaction (HER): 10 mA cm-2], respectively. A Ni-N2S2(+)//Ni-N3P(-) electrolyzer delivered stable overall water splitting for over 100 h. This work introduces a simulation-guided framework for tailoring triple-phase equilibria and a confined-oxidation pathway to engineer highly active and durable single-atom electrocatalysts.

Semiconductor magic-sized nanoclusters (MSCs) possess atomic-level compositional precision and ultrasmall dimensions, allowing accurate modulation of electrochemiluminescence (ECL) properties, essential for advanced bioanalytical applications. However, low intrinsic ECL intensity and poor stability in bipolar electrode (BPE)-ECL systems hinder their broader use. In this work, we addressed these limitations through doping and direct optical crosslinking strategies, achieving a 24-fold boost in the ECL signal and a fivefold stability increase for doped (CdS)34:Ag MSCs compared with original (CdS)34 MSCs. The resulting BPE-ECL biosensing platform was used for the sensitive detection of glucose with a linear detection range of 10 mu M to 1 mM and a detection limit of 3.64 mu M. This approach provides a robust strategy to enhance MSC-based ECL biosensing, paving the way for ultrasensitive, stable biosensors for clinical diagnostics and bioanalysis.

Ion exchange is an effective postsynthesis strategy for the design of colloidal nanomaterials with unique structures and properties. In contrast to the rapid development of cation exchange (CE), the study of anion exchange is still in its infancy and requires an in-depth understanding. Magic-size clusters (MSCs) are important reaction intermediates in quantum dot (QD) synthesis, and studying the ion exchange processes can provide valuable insights into the transformations of QDs. Here, we achieved anion exchange in Cd-based MSCs and elucidated the reaction pathways. We demonstrated that the anion exchange was a stepwise intermolecular transition mediated by covalent inorganic complexes (CICs). We proposed that this transition involved three essential steps: the disassembly of CdE1-MSCs into CdE1-CICs (step 1), an anion exchange reaction from CdE1-CICs to CdE2-CICs (step 2), and assembly of CdE2-CICs to CdE2-MSCs (step 3). Step 3 was the rate-determining step and followed first-order reaction kinetics (kobs = 0.01 min-1; from CdSe-MSCs to CdS-MSCs). Further studies revealed that the activity of foreign anions only affected the reaction kinetics without altering the reaction pathway. The present study provides a deeper insight into the anion exchange mechanisms of MSCs and will further shed light on the synthesis of QDs.

In this work, an electrochemiluminescence (ECL) biosensor based on dual ECL quenching effects of silver nanoclusters (Ag NCs) and multiple cycling amplification was designed to achieve ultrasensitive detection of ATP. The specific recognition of target ATP to aptamer initiated multiple cycling amplification, and a small amount of target was converted into a large number of DNA product chains (S1) by amplification. After S1 opened hairpin DNA 2 (HP2), Ag NCs approached the surface of CdS quantum dots (QDs) modified-electrode by complementary DNA, resulting in a significant decrease of ECL intensity from CdS QDs. The quenching principle is as follows. Firstly, the absorption spectrum of Ag NCs overlaps well with the ECL emission spectrum of CdS QDs, leading to effective ECL resonance energy transfer (ECL-RET); Secondly, Ag NCs could catalyze electrochemical reduction of K2S2O8, leading to consumption of ECL co-reactant and reducing ECL of QDs. The double-ECL quenching achieved ultrasensitive biosensing detection of ATP with a wide range from 1 aM to 1 pM. This present work reported new principle of double-quenching QDs ECL by Ag NCs, and developed a novel ECL biosensor by combining with multiple cycle amplification technique, which has great contribution to the development of QDs ECL and biosensing applications.

Phase changes in colloidal semiconductor nanocrystals (NCs) are essential in material design and device applications. However, the transition pathways have yet to be sufficiently studied, and a better understanding of the underlying mechanisms is needed. In this work, a complete ligand-assisted phase transition from zinc blende (ZB) to wurtzite (WZ) is observed in CdSe nanoplatelets (NPLs). By monitoring with in situ absorption spectra along with electrospray ionization mass spectrometry (ESI-MS), we demonstrated that the transition process is a ligand-assisted covalent inorganic complex (CIC)-mediated phase transition pathway, which involves three steps, ligand exchange on ZB CdSe NPLs (Step 1), dissolution of NPLs to form CICs (Step 2), and conversion of CdSe–CIC assemblies to WZ CdSe NPLs (Step 3). In particular, CICs can be directly anisotropically grown to WZ CdSe NPL without other intermediates, following pseudo-first-order kinetics (kobs = 9.17 × 10−5 s−1). Furthermore, we demonstrated that CICs are also present and play an essential role in the phase transition of ZnS NPLs from WZ to ZB structure. This study proposes a new crystal transformation pathway and elucidates a general phase-transition mechanism, facilitating precise functional nanomaterial design.

All-inorganic nanocrystals (NCs) are of great importance in a range of electronic devices. However, current all-inorganic NCs suffer from limitations in their optical properties, such as low fluorescence efficiencies. Here, we develop a general surface treatment strategy to obtain intensely luminescent all-inorganic NCs (ILANs) by using designed metal salts with noncoordinating anions that play a dual role in the surface treatment process: (i) removing the original organic ligands and (ii) binding to unpassivated Lewis basic sites to preserve the photoluminescent (PL) properties of the NCs. The absolute photoluminescence quantum yields (PLQYs) of red-emitting CdSe/ZnS NCs, green-emitting CdSe/CdZnSeS/ZnS NCs and blue-emitting CdZnS/ZnS NCs in polar solvents are 97%, 80% and 72%, respectively. Further study reveals that the passivated Lewis basic sites of ILANs by metal cations boost the efficiency of radiative recombination of electron-hole pairs. While the passivation of Lewis basic sites leads to a high PLQY of ILANs, the exposed Lewis acidic sites provide the possibility for in situ tuning of the functions of NCs, creating opportunities for direct optical patterning of functional NCs with high resolution.

In this review, we briefly overview the syntheses, compositions, growth mechanisms, and performance improvement strategies of typical II–VI MSCs. Recent advances on the application of II–VI MSCs in photocatalytic CO 2 reduction are introduced.

Achieving nanoconfinement-controlled synthesis of nanoplatelets (NPLs) via solution process under ambient condition remains a challenge. In this work, we developed a general ligand-induced strategy to synthesize colloidal stable all-inorganic semiconductor NPLs with controllable lateral dimensions. By introducing certain metal salts (cations: Zn 2+ and In 3+ , anions: NO 3 − , BF 4 − , or triflate OTf − ), wurtzite-structured (WZ-) CdS, CdSe, CdTe, and alloy Cd 1− x Zn x Se NPLs were directly synthesized in solution through the controlled diffusion of magic-size clusters (MSCs) at room temperature. Mechanism studies revealed that destabilization of MSCs and nanoconfined growth in templates facilitated the formation of NPLs. The present study not only provides a new synthetic route for the preparation of NPLs but also helps to provide insight into their probable formation mechanism and presents an important advance toward the rational design of functional nanomaterials.

Abstract All-inorganic nanocrystals (NCs) are of great importance in a range of electronic devices. However, current all-inorganic NCs suffer from limitations in their optical properties, such as low fluorescence efficiencies. Here, we developed a general surface treatment strategy to obtain intensely luminescent all-inorganic NCs (ILANs). The absolute photoluminescence quantum yields (PLQYs) of red-, green- and blue-emitting ILANs in polar solvents are 97%, 80% and 72%, respectively, which are the highest among inorganically functionalized NCs. Further study revealed that the passivated Lewis basic sites of ILANs by metal cations boosts the efficiency of radiative recombination of electron-hole pairs. While the passivation of Lewis basic sites leads to a high PLQY of ILANs, the exposed Lewis acidic sites provide the opportunities for directly optically patterning of functional NCs with high-resolution. Our studies provide a new surface engineering approach to design functional NCs and create a versatile platform for patterning NCs.

Surface engineering is a critical step in the functionalization of nanomaterials to improve their optical and electrochemical properties. However, this process remains a challenge in II-VI magic-size clusters (MSCs) due to their high sensitivity to the environment. Herein, we developed a general surface modification strategy to design all-inorganic MSCs by using certain metal salts (cation = Zn2+, In3+; Anion = Cl-, NO3 -, OTf-) and stabilized (CdS)34, (CdSe)34 and (ZnSe)34 MSCs in polar solvents. We further investigated the surface states of II-VI MSCs using electrochemiluminescence (ECL). The mechanism study revealed that the ECL emission was attributed to . Two ECL emissions at 556 nm and 530 nm demonstrated two surface passivation modes on (CdS)34 MSCs, which can be tuned by the surface ligands. The achievement of surface engineering opens a new design space for functional MSC compounds.

Luminescent nanoclusters (NCs), with their easy preparation, ultrafine size, low toxicity, and excellent photostability have recently emerged as novel electrochemiluminescence (ECL) emitters. However, relatively low quantum yield (QY) in both aqueous and organic media has impeded their application in ECL emitter evolution. In this mini-review, we discuss the recent development of NCs in ECL with particular focus on their optical properties. We first classify the NCs according to composition and structure, and then summarize four aspects that affect QY, including environment effects, construction, valence state effects and aggregation-induced ECL. The ECL mechanisms based on NCs are elucidated as well. Finally, we briefly discuss the potential applications of NCs in tumor markers test, immunoassay and serum test. This review aims to provide a comprehensive summary of the progress of NCs in ECL, which will motivate researchers to develop NC chemistry and explore their future applications in ECL.

A novel biosensing platform based on the Ag(i) ion-enhanced or Ag nanocluster (NC)-quenched electrochemiluminescence (ECL) of CdSe quantum dots (QDs) was designed for versatile "on-off" assays of thrombin (TB) and miRNA, in which bipedal molecular machine (BMM)-triggered surface programmatic chain reaction (SPCR) coupled with mesoporous silica nanoparticle (MSN) multiple amplification is used to introduce plentiful QDs and Ag+ ions to significantly improve the ECL signal.

A multifunctional DNA nanocage containing CdTe quantum dots (QDs) was prepared. It was applied to the fluorometric detection of human 8-oxoG DNA glycosylase 1 (hOGG1) by exonuclease-assisted cycling amplification technique. When loaded with the cancer drug doxorubicin (Dox), the nanocage is also a versatile probe for fluorescence imaging of cancer cells, and drug delivery to them. The presence of hOGG1 leads to the division of DNA HP1 (containing 8-oxo-dG) and formation of DNA fragments 1 and 2. Then, HP2 is added to hybridize with DNA 1 and produced lots of trigger DNA (containing nucleolin aptamer) by Exo III-aided cycling amplification. The DNA nanocage was fabricated by linking the trigger DNA to multiple specific DNA strands, and the fluorescent CdTe QDs were further conjugated to the DNA nanocage for sensitive detection of hOGG1 activity. After Dox is incorporated into the DNA nanocage, the fluorescence of Dox is turned off. Once the DNA nanocage enters the MCF-7 cells, the Dox is released and its fluorescence (measured at excitation/emission wavelengths of 480/560 nm) is turned on. The DNA nanocage containing fluorescent QDs and Dox was successfully applied to the fluorometric detection of hOGG1, fluorescence imaging, and therapy of cancer cells, which has great promise in clinical application and treatment of cancer.

Herein, a new multifunctional DNA nanotube (DNANT) was self-assembled and used to load Ru(phen)32+ and methylene blue (MB) as amplified signal probes for versatile electrochemiluminescence (ECL) and electrochemical (EC) "on-off" assays of Dam methylase (MTase) and aflatoxin B1 (AFB1). The DNA nanotube as a carrier could immobilize numerous MB or Ru(phen)32+ species in the double-stranded DNA (dsDNA) to significantly amplify signals, which enabled highly sensitive ECL and electrochemical detection of dual targets. The target Dam MTase first catalyzed the methylation of hairpin DNA (H1), and then the methylated DNA was cleaved by endonuclease DpnI to expose a single-strand DNA. After the Ru(phen)32+-DNANT or MB-DNANT signal probes were assembled to the electrode by hybridization, remarkable "signal on" states for amplified ECL or EC assays of MTase were obtained. Furthermore, in the presence of the target AFB1, the structure of DNANTs collapsed due to the specific binding of AFB1 to aptamer S2 in NTs, which led to the release of signal probes (Ru(phen)32+ or MB) from the electrode to achieve "signal off" state for dual detection of AFB1. Taking advantage of the multifunctional DNANT amplification signal probes, the versatile biosensors showed good analytical performance with very wide linear ranges (0.001-100 U mL-1 and 0.0001-100 ng mL-1 for MTase and AFB1 assay by DPV) and lower detection limits (2.1 × 10-4 U mL-1 and 0.018 pg mL-1 for MTase and AFB1 by DPV). This is the first time that ECL and EC "on-off" methods have been achieved separately for dual target assays, which opens a new avenue of DNANT-based signal amplification strategyies for the versatile design of biosensors in various biological detections.

In this work, a new 3D DNA nanosphere was ingeniously designed and fabricated, which was used to combine with multiple enzyme-free amplification strategy to develop a photoelectrochemical (PEC) biosensing platform for ultrasensitive detection of carcinoembryonic antigen (CEA). The 3D DNA nanostructure was self-assembled by base complementary pairing in a few minutes and rolling circle amplification (RCA) reaction. The intense photocurrent derived from Au NPs/ZnSe QDs can be effectively decreased by 3D DNA nanospheres assembled on the electrode, making photoelectric signal present “off” state. The specific binding of target CEA with its hairpin (HP1) aptamer opens HP1 structure, which initiated multiple enzyme-free strand displacement amplification (SDA) reaction and generated a large number of single strands DNA S1. Then S1 competitively binds to capture DNA on the electrode to release 3D DNA nanospheres, thus the photocurrent signal became “on” state for achieving amplified assay of target CEA. The proposed PEC biosensor exhibits excellent performance with a wide linear range of 1.0 fg/mL to 10 ng/mL and a low detection limit of 0.12 fg/mL for CEA, which was successfully applied for the assay of real serum samples with good precision. The reported strategy opens a new simple way for PEC biosensor using DNA nanostructure, showing huge potential in clinical application research.

A novel DNA hydrogel-amplified versatile fluorescence platform combined with hybridization chain reaction (HCR) and DNA walking multiple amplification was developed for ultrasensitive detection of miRNA. The DNA hydrogel was loaded with large amounts of SYBR Green (SG) I dyes or CdTe quantum dots (QDs) to assemble versatile signal probes.