Ultrasensitive Electrochemiluminescence Biosensor with ZIF-67@MXene as an Efficient Co-Reaction Accelerator and Plasmonic Nanozyme as a Smart Signal Amplification Probe.

Exploring novel electrochemiluminescence (ECL) co-reaction accelerators to construct ultrasensitive sensing systems is a prominent focus for developing advanced ECL sensors. However, challenges still remain in finding highly efficient accelerators and understanding their promoting mechanisms. In this paper, ZIF-67@MXene nanosheet composites, with highly conductive in-plane structure and confined-stable pore/channel, are designed to act as high-efficient co-reaction accelerators and achieve a significant enhancement in the luminol-H2O2 based ECL system. Mechanism investigation suggests that hydroxyl radicals (·OH) and singlet oxygen (1O2) can be selectively and preferentially generated on ZIF-67@MXene due to the stable and efficient absorption of ·OH and 1O2, leading to a remarkable enhancement in the ECL efficiency of luminol (830%). Finally, by designing a plasmonic NH2-MIL-88@Pd nanozyme, an "on-off" switch immunosensor is constructed for the detection of prostate-specific antigen (PSA). Based on the multiple signal amplification effect, the linear detection range for PSA is expanded by three orders of magnitude. The detection limit is also improved from 1.44 × 10-11 to 9.1 × 10-13 g mL-1. This work proposes an effective method for the preparation of highly efficient co-reaction accelerators and provides a new strategy for the sensitive detection of cancer markers.

Construction of Multi-Mode Photoelectrochemical Immunoassays for Accurate Detection of Cancer Markers: Assisted with MOF-Confined Plasmonic Nanozyme.

In clinical diagnostics, sensitive and accurate biomarker monitoring is greatly challenged by the limitations of false positive/negative errors in single-modal photoelectrochemical analysis. Herein, we propose a multimode immunoassay by integrating photoelectrochemical, colorimetric, and photothermal imaging analysis into one electrode. The immunosensors could simultaneously achieve three detection modes at one electrode, which provided a new pathway for the accurate detection of the target prostate-specific antigen (PSA) and circumvented false-positive or negative errors during the detection process. To this end, an integrated multifunctional chip (TiO2/ZIF-8/Cu(II)) was first constructed via in situ embedding of Cu(II) in the Metal-organic framework growth process. Then, an alkaline phosphatase-labeled magnetic probe was designed to achieve split-type detection for PSA. In a sodium thiophosphate solution, the in situ generated H2S could react with Cu(II) to form small-size CuS due to the nanoconfinement of ZIF-8 and thus result in the formation of p-n heterojunctions (TiO2/ZIF-8/CuS). The TiO2/ZIF-8/CuS could efficiently improve the light-harvesting ability and facilitate the charge separation efficiency, thus finally resulting in an increased photocurrent in the PEC mode. Furthermore, by constructing the portable colorimetric and photothermal sensors based on the Arduino microcontroller and photothermal imager, the TiO2/ZIF-8/CuS also provided point-of-care and visual detection modes, as the in situ-formed CuS exhibited peroxidase-mimicking activity and outstanding photothermal properties. The work had important prospects for establishing multimode immunoassays for the accurate detection of cancer markers in early disease diagnosis.

Causal effect of age first had sexual intercourse and lifetime number of sexual partners on cervical cancer.

Objective: In this study, we aimed to investigate whether age first had sexual intercourse (AFSI) and lifetime number of sexual partners (LNSP) have a direct causal effect on cervical cancer by Mendelian randomization (MR) analysis. Methods: Four approaches were used for MR Analysis, including MR-Egger, weighted method, weighted median, and inverse variance weighted (IVW). MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) as well as MR-Egger regression analysis were conducted to detect whether there was pleiotropy between IVs and outcome, and the outlier SNPs can be detected by MR-PRESSO. The presence or absence of heterogeneity among IVs was suggested according to Cochran's Q statistic. Leave-one-out sensitivity analysis was performed to identify and remove SNPs which could independently change the results. We corrected the results using Bonferroni correction. Results: From the results of IVW, AFSI had a negative effect on cervical cancer (OR = 0.996, 95 % CI: 0.995, 0.998 P = 1.70E-07), which still persisted after Bonferroni correction. However, no causal effect of LNSP on cervical cancer was found according to the IVW results (OR = 1.003, 95 % CI: 1.000, 1.007, P = 0.071). From the results of MR-PRESSO and MR-Egger, no SNP with horizontal pleiotropy between cervical cancer was detected and no SNP was identified as an outlier SNP. Cochran's Q statistic suggested that no heterogeneity existed among IVs of AFSI and LNSP. According to Leave-one-out analysis, the results of MR did not change after excluding any single IV. Conclusion: This MR study reveals that early AFSI has a causal effect on cervical cancer.

Construction of smartphone-adapted signal visualization platform for dual-mode detection of H2S based on integrated metal-organic framework nanoprobes.

Hydrogen sulfide (H2S) is a toxic contaminant and has great influence on many physiological processes. Due to various pathophysiological roles and environmental pollution problems, it is necessary to construct and develop simple and portable monitoring sensors for the precise detection of H2S. Herein, we developed a smartphone-adapted dual-mode detection platform by integrating the colorimetric and photothermal imaging analysis into a metal-organic framework-based chip (ZIF-8/Cu). Due to the nanoconfinement effect of ZIF-8, small-sized plasmonic CuS could be in-situ formed during the detection procedure of H2S and endowed the chips with excellent photothermal properties. By constructing a smartphone-adapted photothermal imager, the metal-organic framework-based chip could achieve a portable photothermal imaging analysis of H2S. Moreover, as the formed CuS was a good peroxidase-like nanozyme, the chips could also be used to trigger the enzymic catalytic reaction toward the chromogenic reaction of 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2, thus providing another colorimetric sensing mode by using a smartphone App. In this smartphone-adapted visualization platform, the portable chemosensors could simultaneously achieve double detection modes at one electrode, which provided a new pathway for the accurate detection of H2S and circumvented the false-positive or negative errors during the detection process. Besides, by using the finite difference time domain (FDTD) simulation method, the in-depth mechanism, including the plasmonic effect and spatial electromagnetic field distribution, was explored to provide a possible reason for the excellent sensing performance of the dual-mode visualization platform. This work provides a new insight into the construction of the accurate, portable and smart sensing platform in the visual screening of H2S.

Engineering contact curved interface with high-electronic-state active sites for high-performance potassium-ion batteries.

Potassium-ion batteries (PIBs) have attracted ever-increasing interest due to the abundant potassium resources and low cost, which are considered a sustainable energy storage technology. However, the graphite anodes employed in PIBs suffer from low capacity and sluggish reaction kinetics caused by the large radius of potassium ions. Herein, we report nitrogen-doped, defect-rich hollow carbon nanospheres with contact curved interfaces (CCIs) on carbon nanotubes (CNTs), namely CCI-CNS/CNT, to boost both electron transfer and potassium-ion adsorption. Density functional theory calculations validate that engineering CCIs significantly augments the electronic state near the Fermi level, thus promoting electron transfer. In addition, the CCIs exhibit a pronounced affinity for potassium ions, promoting their adsorption and subsequently benefiting potassium storage. As a result, the rationally designed CCI-CNS/CNT anode shows remarkable cyclic stability and rate capability. This work provides a strategy for enhancing the potassium storage performance of carbonaceous materials through CCI engineering, which can be further extended to other battery systems.

Atomically Fe-anchored MOF-on-MOF nanozyme with differential signal amplification for ultrasensitive cathodic electrochemiluminescence immunoassay.

The successful application of electrochemiluminescence (ECL) in immunoassays for clinical diagnosis requires stable electrodes and high-efficient ECL signal amplification strategies. Herein, the authors discovered a new class of atomically dispersed peroxidase-like nanozymes with multiple active sites (CoNi-MOF@PCN-224/Fe), which significantly improved the catalytic performance and uncovered the underlying mechanism. Experimental studies and theoretical calculation results revealed that the nanozyme introduced a Fenton-like reaction into the catalytic system and the crucial synergistic effects of definite active moieties endow CoNi-MOF@PCN-224/Fe strong electron-withdrawing effect and low thermodynamic activation energy toward H2O2. Benefiting from the high peroxidase-like activity of the hybrid system, the resultant ECL electrode exhibited superior catalytic activity in the luminol-H2O2 system and resulted in an ≈17-fold increase in the ECL intensity. In addition, plasmonic Ag/Au core-satellite nanocubes (Ag/AuNCs) were designed as high-efficient co-reactant quenchers to improve the performance of the ECL immunoassay. On the basis of the differential signal amplification strategy (DSAS) proposed, the immunoassay displayed superior detection ability, with a low limit of detection (LOD) of 0.13 pg mL-1 for prostate-specific antigen (PSA). The designed atomically anchored MOF-on-MOF nanozyme and DSAS strategy provides more possibilities for the ultrasensitive detection of disease markers in clinical diagnosis.

Fabrication and nano-engineering of non-/noble metal-coupled plasmonic heterostructures for ultrasensitive photoelectrochemical immunoassays.

To achieve reliable and ultrasensitive detection for disease markers in PEC bioanalysis, constructing and nano-engineering of ideal photoelectrodes and signal transduction strategies are of vital importance. Herein, a non-/noble metal coupled plasmonic nanostructure (TiO2/r-STO/Au) was tactically designed with high-efficient PEC performance. Evidenced by the DFT and FDTD calculations, the reduced SrTiO3 (r-STO) was found to support the localized surface plasmon resonance due to the sufficiently increased and delocalized local charge in r-STO. Under the synergistic coupling of plasmonic r-STO and AuNPs, the PEC performance of TiO2/r-STO/Au was found remarkably promoted with reduced onset potential. This merit supported TiO2/r-STO/Au as a self-powered immunoassay via a proposed oxygen-evolution-reaction mediated signal transduction strategy. With the increase of the target biomolecules (PSA), the catalytic active sites of TiO2/r-STO/Au would be blocked and result in the decrease of the oxygen evaluation reaction. Under optimal conditions, the immunoassays exhibited an excellent detection performance with a LOD as low as 1.1 fg/mL. This work proposed a new type of plasmonic nanomaterial for ultrasensitive PEC bioanalysis.

Electrospun carbon-based nanomaterials for next-generation potassium batteries.

Rechargeable potassium (K) batteries that are of low cost, with high energy densities and long cycle lives have attracted tremendous interest in affordable and large-scale energy storage. However, the large size of the K-ion leads to sluggish reaction kinetics and causes a large volume variation during the ion insertion/extraction processes, thus hindering the utilization of active electrode materials, triggering a serious structural collapse, and deteriorating the cycling performance. Therefore, the exploration of suitable materials/hosts that can reversibly and sustainably accommodate K-ions and host K metals are urgently needed. Electrospun carbon-based materials have been extensively studied as electrode/host materials for rechargeable K batteries owing to their designable structures, tunable composition, hierarchical pores, high conductivity, large surface areas, and good flexibility. Here, we present the recent developments in electrospun CNF-based nanomaterials for various K batteries (e.g., K-ion batteries, K metal batteries, K-chalcogen batteries), including their fabrication methods, structural modulation, and electrochemical performance. This Feature Article is expected to offer guidelines for the rational design of novel electrospun electrodes for the next-generation K batteries.

A molecular probe carrying anti-tropomyosin 4 for early diagnosis of cerebral ischemia/reperfusion injury.

In vivo imaging of cerebral ischemia/reperfusion injury remains an important challenge. We injected porous Ag/Au@SiO2 bimetallic hollow nanoshells carrying anti-tropomyosin 4 as a molecular probe into mice with cerebral ischemia/reperfusion injury and observed microvascular changes in the brain using photoacoustic imaging with ultrasonography. At each measured time point, the total photoacoustic signal was significantly higher on the affected side than on the healthy side. Twelve hours after reperfusion, cerebral perfusion on the affected side increased, cerebrovascular injury worsened, and anti-tropomyosin 4 expression increased. Twenty-four hours after reperfusion and later, perfusion on the affected side declined slowly and stabilized after 1 week; brain injury was also alleviated. Histopathological and immunohistochemical examinations confirmed the brain injury tissue changes. The nanoshell molecular probe carrying anti-tropomyosin 4 has potential for use in early diagnosis of cerebral ischemia/reperfusion injury and evaluating its progression.

Ion-Exchange Reaction-Mediated Hierarchical Dual Z-Scheme Heterojunction for Split-Type Photoelectrochemical Immunoassays.

Photoelectrochemical (PEC) immunoassays with ultrasensitive detection abilities are highly desirable for in vitro PEC diagnosis and biological detection. In this paper, dual Z-scheme PEC immunoassays with hierarchical nanostructures (TiO2@NH2-MIL-125@CdS) are synthesized through epitaxial growth of MOF-on-MOF and further in situ derivatization. The dual Z-scheme configuration not only extends the light absorption range but also increases the redox ability due to the interface structure nanoengineering, which synergistically suppresses bulk carrier recombination and promotes the charge transfer efficiency at the electron level. Furthermore, a smart MOF-derived labeling probe (CuO@ZnO nanocube) is designed to develop a split-type PEC biosensor by using prostate-specific antigen (PSA) as a target biomarker. In the presence of PSA, the Ab2-labeled CuO@ZnO would specifically bond to the dual Z-scheme electrode. Then, the MOF-derived CuO@ZnO is dissolved by hydrochloric acid to release Cu2+, which could replace Cd2+ via an ion-exchange reaction, thus leading to the decrease of the photocurrent due to the destruction of the dual Z-scheme configuration. In typical applications, the split-type PEC immunoassay exhibits an excellent detection performance for PSA with a LOD as low as 0.025 pg·mL-1.

Do reverse total shoulder replacements have better clinical and functional outcomes than hemiarthroplasty for patients undergoing proximal humeral tumor resection using devitalized autograft composite reconstruction: a case-control study.

OBJECTIVE: To compare the efficacy and prognosis of reverse total shoulder arthroplasty (rTSA) with shoulder hemiarthroplasty (SHA) using devitalized autograft or allograft composite reconstruction after proximal humeral tumor resection. METHODS: We retrospectively reviewed patients who underwent SHA (32) and rTSA (20) for tumor resections of the proximal humerus from January 2014 to July 2020. The clinical results included duration of the operation, intraoperative blood loss, bone union, visual analog scale (VAS) score, shoulder range of motion (ROM), American Shoulder and Elbow Surgeons (ASES) shoulder score, recurrence, and overall survival. RESULTS: Fifty-two patients were followed up for a mean of 30 months. Thirty-two patients were SHA with allograft-prosthetic composite (APC) reconstructions, while other 20 were rTSA with devitalized autograft-prosthetic composite reconstructions. At the end of the follow-up, 2 recurrence, 3 postoperative infections, and 4 subluxations occurred among the SHA patients. Two patients in the rTSA group had postoperative anterior dislocation and underwent revision surgery with surgical mesh, and 2 (2/20) had grade II scapular notching. The mean VAS score of the shoulder was 1.5 ± 0.8 in the rTSA group and 2.3 ± 1.2 in the SHA group (p < 0.05). The mean active forward flexion of the shoulder joint was 50.6 ± 6.0 in the SHA group and 100 ± 7.6 in the rTSA group (p < 0.05). The ASES shoulder score was 78 ± 3.0 in the rTSA group and 52 ± 5.6 in the SHA group (p < 0.05). The overall 3-year survival rate of all patients was 60.0%, and patients in the rTSA group showed better survival in terms of the mean 3-year OS than patients in the SHA group (p = 0.04). CONCLUSION: rTSA with devitalized autograft-prosthetic composite can offer a reasonable reconstruction of the shoulder joint after Malawer type I tumor resection. Compared with patients who underwent SHA, patients who underwent rTSA present good outcomes, a better range of motion, better bone union, and no increase in instability rate in the mid-term.

Plasmon-enhanced unidirectional charge transfer for efficient solar water oxidation.

Precise modulation and nano-engineering of photoelectrochemical (PEC) materials, with high-speed charge separation efficiency and broad spectral response, are of significant importance in improving the PEC catalytic activities. Herein, by rational design of material structures, 3D-coaxial plasmonic hetero-nanostructures (carbon cloth@TiO2@SrTiO3-Au, CC@TiO2@SrTiO3-Au) are tactfully fabricated, which exhibit superior solar energy conversion efficiency in PEC water splitting with a current density reaching up to 23.56 mA cm-2 (1.23 V vs. RHE). More specific research and in-depth simulations reveal that the enhanced PEC performance should be attributed to the high-speed charge transfer channels of CC@TiO2@SrTiO3 and excellent light utilization ability stemming from the surface plasmon resonance and strong light-scattering of the 3D-coaxial frameworks. This study provides new strategies for the design of plasmon-enhanced PEC nanocatalysts and will benefit the development of photoelectric energy conversion.

Effects of Qingshen Granules on Immune Function in Patients with Comorbid Chronic Renal Failure and Damp-Heat Syndrome: A Multicenter, Randomized, Controlled Trial.

OBJECTIVE: The current study sought to compare the effects of the addition of Qingshen granules to conventional Western medicine on immune function in patients with comorbid chronic renal failure and damp-heat syndrome and to explore the possible mechanisms responsible for any differences observed. METHODS: Through a multicenter, randomized, controlled study, a total of 282 eligible patients were divided into experimental (n = 136) and control groups (n = 146). All of the patients were treated with conventional Western medical therapy. The experimental group also received Qingshen granules three times daily for 12 weeks. Clinical efficacy was observed in the two groups. Peripheral blood levels of CD4+ T cells, CD8+ T cells, Th17 cells, nuclear factor-κB p65 (NF-κB p65) activity, serum interleukin-17 (IL-17), serum interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), tumor necrosis factor receptor-associated factor 6 (TRAF6), fibronectin (FN), and type IV collagen (Col-IV) were detected in both groups. RESULTS: The total clinical curative effective rate was significantly higher (p < 0.05) in the experimental group (79.41%) than in the control group (67.12%). Before treatment, there were no significant differences in CD4+/CD8+ T cell ratio, Th17 cell level, NF-κB p65 activity, serum IL-17, IL-6, TNF-α, TRAF6, FN, and Col-IV between the experimental and control groups (p > 0.05); however, all of the measures were significantly higher than those observed in a healthy comparison group (p < 0.05 or p < 0.01). After treatment, the above indexes in the experimental group were significantly lower than those before treatment (p < 0.05 or p < 0.01). Similarly, NF-κB p65 activity, serum IL-17, TNF-α, TRAF6, FN, and Col-IV in the control group were significantly lower than the levels observed prior to treatment (p < 0.05 or p < 0.01); however, while all of the other indexes were lower than those observed before treatment, the differences were not statistically significant (p > 0.05). CONCLUSION: Qingshen granules adjust immune dysfunction, improve immunity mediated inflammatory response, and attenuate renal fibrosis in patients with comorbid chronic renal failure and damp-heat syndrome.

Anionic metal-organic framework as a unique turn-on fluorescent chemical sensor for ultra-sensitive detection of antibiotics.

Herein, an anionic metal-organic framework, formulated as {[Zn3(OH)(bmipia)(H2O)3]4·[Zn(H2O)6.5]2}n (FCS-3), was prepared from zinc ions and semi-rigid carboxylate ligands of 5-[N,N-bis(5-methylisophthalic acid)amion] isophthalic acid (H6bmipia) and was employed as a unique fluorescence turn-on chemical sensor for the ultra-sensitive detection of various antibiotics in the aqueous phase.

Plasmonic SERS Au Nanosunflowers for Sensitive and Label-Free Diagnosis of DNA Base Damage in Stimulus-Induced Cell Apoptosis.

Molecular diagnosis and accurate damage analysis of complex genomic DNAs in tumor cells are crucial to the theranostics of cancers but still a huge challenge. Herein, by designed preparation of a uniform plasmonic sunflower-like assembly gold (Au) nanostructure that is capable of efficient DNA capture and providing high-density gap-plasmon "hot spots" for adequate surface-enhanced Raman spectroscopy (SERS) enhancement, we succeeded in sensitive and reliable label-free SERS detection of DNA damage in electrostimulus-induced apoptotic cancer cells at the DNA base level for the first time. The SERS results showed that the external electrostimulus (at 1.2 V, for 5 min) was almost harmless to normal healthy cells, but it caused pronounced double strand break and adenine base damage in cancer cell DNAs, which effectively destroyed the reproduction and transcription of DNAs and ultimately induced cell apoptosis. The developed sensing platform and method are promising for cell study of genetically related diseases.

Programmable Organic-Free Negative Differential Resistance Memristor Based on Plasmonic Tunnel Junction.

A novel negative differential resistance (NDR) phenomenon is reported herein based on planar plasmonic tunnel junction, resulting from plasmon-assisted long-range electron tunneling (P-tunneling) and electronic caching effect of Au@SiO2 nanoparticles. The tunnel junction is made of shell-insulated Au@SiO2 nanoparticle nanomembrane, in which SiO2 shells act as a tunable tunneling barrier, while the Au core not only support the plasmonic effect to enable P-tunneling, but also act as electronic caches to render NDR responses. The NDR peak voltage and current can be programmably controlled by varying the thickness of SiO2 shell and the size of Au core to tune barrier level for electron transport. In addition, light induced plasmonic effect can be further managed to regulate the NDR behavior by fine-tuning P-tunneling. The phenomenon is exploited for robust use as memristors. The work provides a new mechanism for the generation of NDR effect and may open a way for the development of robust and new conceptual nanoelectronic devices.

Quasi-Photonic Crystal Light-Scattering Signal Amplification of SiO2-Nanomembrane for Ultrasensitive Electrochemiluminescence Detection of Cardiac Troponin I.

Signal amplification for electrochemiluminescence (ECL) plays a significant role in ultrasensitive detection of disease biomarkers. We report herein a new signal amplification strategy-quasi-photonic crystal nanomembrane-based light scattering enhancement for ECL signal amplification, via fabricating a novel close-packed monolayered SiO2-nanomembrane as solid-state ECL electrodes. In the system, the quasi-photonic crystal structure of the monolayered SiO2-nanomembrane led to intense light scattering within the nanofilm, which significantly increases the photon flux and then definitely improves the excitation number of the luminescent molecules (Ru(bpy)32+). Reinforced by the nanostructured electrode surface of the nanomembrane, the as-prepared ECL electrode exhibited significant ECL enhancement, ∼77-fold enhancement in the classic Ru(bpy)32+-TPrA system. We further constructed a sandwich-type SiO2-nanomembrane based solid-state ECL immunobiosensor for ultrasensitive detection of cardiac troponin I (cTnI). Under optimal conditions, the immunobiosensor exhibited a very low limit of detection (LOD) of 5.6 fg mL-1 for cTnI. Due to the cheap and easy availability of the materials, this study and findings not only provide an efficient way to improve the ECL intensity but also benefit the design of novel ECL electrodes for various biomarker detections.

Unprecedented efficient electron transport across Au nanoparticles with up to 25-nm insulating SiO2-shells.

Quantum tunneling is the basis of molecular electronics, but often its electron transport range is too short to overcome technical defects caused by downscaling of electronic devices, which limits the development of molecular-/nano-electronics. Marrying electronics with plasmonics may well present a revolutionary way to meet this challenge as it can manipulate electron flow with plasmonics at the nanoscale. Here we report on unusually efficient temperature-independent electron transport, with some photoconductivity, across a new type of junction with active plasmonics. The junction is made by assembly of SiO2 shell-insulated Au nanoparticles (Au@SiO2 NPs) into dense nanomembranes of a few Au@SiO2 layers thick and transport is measured across these membranes. We propose that the mechanism is plasmon-enabled transport, possibly tunneling (as it is temperature-independent). Unprecedentedly ultra-long-range transport across one, up to even three layers of Au@SiO2 in the junction, with a cumulative insulating (silica) gap up to 29 nm/NP layer was achieved, well beyond the measurable limit for normal quantum mechanical tunneling across insulators (~2.5 nm at 0.5-1 V). This finding opens up a new interdisciplinary field of exploration in nanoelectronics with wide potential impact on such areas as electronic information transfer.

Efficient Electrogenerated Chemiluminescence of Tris(2,2'-bipyridine)ruthenium(II) with N-Hydroxysulfosuccinimide as a Coreactant for Selective and Sensitive Detection of l-Proline and Mercury(II).

Developing rapid, specific, and low-cost electrogenerated chemiluminescence (ECL) systems remains a compelling goal for many applications including environmental analysis, clinical diagnostics, and food safety. In this study, N-hydroxysuccinimide (NHS) esters, especially N-hydroxysulfosuccinimide (NHSS), was exploited for the first time as an efficient coreactant for anodic Ru(bpy)32+ ECL in neutral medium. Among the three tested NHS esters (NHS, NHSS, NHPI), the NHSS exhibited much higher ECL intensity and stability than the sulfonate-free esters, suggesting the essential role of both the N-hydroxy (NOH) and sulfonate (SO3H) moieties in the developed Ru(bpy)32+ ECL system. The ECL generation process is rather straightforward, not requiring time-consuming fabrication/modification steps of electrodes. The anodic Ru(bpy)32+-NHSS system achieved ECL detections with high selectivity and sensitivity toward l-proline (LOD = 50 nM) and Hg2+ (LOD = 10 nM), with a linear range of 0.5-200 µM and 0.1-25 µM, respectively. The method showed good recoveries (95.2-104.8%) for l-proline and Hg2+ detection in real samples. This study is a successful step toward the development of new coreactants and may open new avenues for the applications of N-hydroxy compounds in ECL sensing.

Nanoengineered Metasurface Immunosensor with over 1000-Fold Electrochemiluminescence Enhancement for Ultra-sensitive Bioassay.

Enhancing electrochemiluminescence (ECL) with plasmonic materials is promising but still a long-standing barrier to improve its sensitivity for ultrasensitive bioassays, due to the lack of comprehensive understanding and effective strategies to fully utilize plasmonic effects for ECL enhancement. Herein, by insulating gold nanoparticles with silica shells (Au@SiO2 NPs), and finely tuning their core/shell sizes and controlling interparticle spacing via assembling them into a dense nanomembrane, we develop a novel 2D metasurface. Due to well-controlled high density "hot spots" and 2D ordered arrangement of the unit NPs in the nanomembrane, the metasurfaced ECL electrode shows over 1,000-fold plasmonic ECL enhancement for the classical Ru(bpy)32+-tripropylamine system, which is two orders of magnitude higher than ever reported (<30-fold). Such fabricated ECL biosensor demonstrates superior detection performance for prostate-specific antigen with a detection limit of 3 fg mL-1. Our results provide understanding of plasmonic effects for ECL enhancement and will benefit for biosensor construction for ultrasensitive bioassays.