DNA Framework-Based Programmable Atom-Like Nanoparticles for Non-Coding RNA Recognition and Differentiation of Cancer Cells.

The cooperative diagnosis of non-coding RNAs (ncRNAs) can accurately reflect the state of cell differentiation and classification, laying the foundation of precision medicine. However, there are still challenges in simultaneous analyses of multiple ncRNAs and the integration of biomarker data for cell typing. In this study, DNA framework-based programmable atom-like nanoparticles (PANs) are designed to develop molecular classifiers for intra-cellular imaging of multiple ncRNAs associated with cell differentiation. The PANs-based molecular classifier facilitates signal amplification through the catalytic hairpin assembly. The interaction between PAN reporters and ncRNAs enables high-fidelity conversion of ncRNAs expression level into binding events, and the assessment of in situ ncRNAs levels via measurement of the fluorescent signal changes of PAN reporters. Compared to non-amplified methods, the detection limits of PANs are reduced by four orders of magnitude. Using human gastric cancer cell lines as a model system, the PANs-based molecular classifier demonstrates its capacity to measure multiple ncRNAs in living cells and assesses the degree of cell differentiation. This approach can serve as a universal strategy for the classification of cancer cells during malignant transformation and tumor progression.

Antidiabetic Close Loop Based on Wearable DNA-Hydrogel Glucometer and Implantable Optogenetic Cells.

Diabetes mellitus and its associated secondary complications have become a pressing global healthcare issue. The current integrated theranostic plan involves a glucometer-tandem pump. However, external condition-responsive insulin delivery systems utilizing rigid glucose sensors pose challenges in on-demand, long-term insulin administration. To overcome these challenges, we present a novel model of antidiabetic management based on printable metallo-nucleotide hydrogels and optogenetic engineering. The conductive hydrogels were self-assembled by bioorthogonal chemistry using oligonucleotides, carbon nanotubes, and glucose oxidase, enabling continuous glucose monitoring in a broad range (0.5-40 mM). The optogenetically engineered cells were enabled glucose regulation in type I diabetic mice via a far-red light-induced transgenic expression of insulin with a month-long avidity. Combining with a microchip-integrated microneedle patch, a prototyped close-loop system was constructed. The glucose levels detected by the sensor were received and converted by a wireless controller to modulate far-infrared light, thereby achieving on-demand insulin expression for several weeks. This study sheds new light on developing next-generation diagnostic and therapy systems for personalized and digitalized precision medicine.

Sub-Second Electrochemiluminescence Imaging Assay of SARS-CoV-2 Nucleocapsid Protein Based on Reticulation of Endo-Coreactants.

The nonphotodriven electrochemiluminescence (ECL) imageology necessitates concentrated coreacting additives plus longtime exposures. Seeking biosafe and streamlined ensembles can help lower the bar for quality ECL bioimaging to which call the crystallized endo-coreaction in nanoreticula might provide a potent solution. Herein, an exo-coreactant-free ECL visualizer was fabricated out in one-pot, which densified the dyad triethylamine analogue: 1,4-diazabicyclo-[2.2.2]octane (DABCO) in the lamellar hive of 9,10-di(p-carboxyphenyl)anthracene (DPA)-Zn2+. This biligated non-noble metal-organic framework (m-MOF) facilitated a self-contained anodic ECL with a yield as much as 70% of Ru(bPy)32+ in blank phosphate buffered saline. Its featured two-stage emissions rendered an efficient and endurant CCD imaging at 1.0 V under mere 0.5 s swift snapshots and 0.1 s step-pulsed stimulation. Upon structural and spectral cause analyses as well as parametric set optimization, simplistic ECL-graphic immunoassay was mounted in the in situ imager to enact an ultrasensitive measurement of coronaviral N-protein in both signal-on and off modes by the privilege of straight surface amidation on m-MOFs, resulting in a wide dynamic range (10-4-10 ng/mL), a competent detection limit down to 56 fg/mL, along with nice precision and parallelism in human saliva tests. The overall work manifests a rudimentary endeavor in self-sufficient ECL visuality for brisk, biocompatible, and brilliant production of point-of-care diagnostic "Big Data".

Amplification of an Electrochemiluminescence-Emissive Aptamer into DNA Nanotags for Sensitive Fecal Calprotectin Determination.

The precision additive manufacturing and tessellated multitasking out of the structural DNA nanotechnology enable a configurable expression of densified electrochemiluminescent (ECL) complexes, which would streamline the bioconjugation while multiplying signals. Herein, a completely DNA-scaffold ECL "polyploid" was replicated out via the living course of rolling circle amplification. The amplicon carried the aptameric sequences of ZnPPIX/TSPP porphyrin as photoreactive centers that rallied at periodical intervals of the persistent extension into a close-packed nanoflower, ZnPDFI/II. Both microscopies and electrophoresis proved the robust nesting of guests at their deployed gene loci, while multispectral comparisons among cofactor substituents pinpointed the pivotal roles of singlet seclusion and Zn2+-chelation for the sake of intensive ECL irradiation. The adversity-resilient hydrogel texture made lipoidal filmogens as porphyrinic ECL prerequisites to be of no need at all, thus not only simplifying assay flows but also inspiring an in situ labeling plan. Upon bioprocessing optimization, an enriched probe ZnPDFIII was further derived that interpolated the binding motif related to calprotectin as validated by molecular docking and affinity titration. With it being a strongly indicative marker of inflammatory bowel disease (IBD), a competitive ECL aptasensing strategy was contrived, managing a signal-on and sensitive detection in mild conditions with a subnanogram-per-milliliter limit of detection by 2 orders of magnitude lower than the standard method as well as a comparable accuracy in clinical stool sample testing. Distinct from those conventional chemophysical rebuilding routes, this de novo biosynthetic fusion demonstrated a promising alternative toward ECL-source bioengineering, which may intrigue vibrant explorations of other ECL-shedding fabrics and, accordingly, a new bioanalytic mode downstream.

Point-of-Care Diagnosis on Selenium Nutrition Based on Time-Resolved Fluorometric Glycoaffinity Chromatography.

Given the lack of timely evaluation of the well-received selenium fortification, a neat lateral-flow chromatographic solution was constructed here by using the recently identified urinary selenosugar (Sel) as a strongly indicative marker. As there are no ready-made receptors for this synthetic standard, phenylboronic acid (PBA) esterification and Dolichos biflorus agglutinin (DBA) affinity joined up to pinch and pin down the analyte into a sandwich-type glycol complex. Pilot lectin screening on homemade glycan microarrays verified such a new pairing between dual recognizers as PBA-Sel-DBA with a firm monosaccharide-binding constant. To quell the sample autofluorescence, europium nanoparticles with efficient long-life afterglow were employed as conjugating probes under 1 µs excitation. After systematic process optimizations, the prepared Sel-dipstick achieved swift and sensitive fluorometry over the physiological level of the target from 0.1 to 10 µM with a detection limit down to 0.06 µM. Further efforts were made to eliminate matrix effects from both temperature and pH via an approximate formula. Upon completion, the test strips managed to quantify the presence of Sel in not just imitated but real human urine, with comparable results to those in the references. As far as we know, this would be the first in-house prototype for user-friendly and facile diagnosis of Se nutrition with fair accuracy as well as selectivity. Future endeavors will be invested to model a more traceable Se-supplementary plan based on the rhythmic feedback of Sel excretion.

Controllable mitochondrial aggregation and fusion by a programmable DNA binder.

DNA nanodevices have been feasibly applied for various chemo-biological applications, but their functions as precise regulators of intracellular organelles are still limited. Here, we report a synthetic DNA binder that can artificially induce mitochondrial aggregation and fusion in living cells. The rationally designed DNA binder consists of a long DNA chain, which is grafted with multiple mitochondria-targeting modules. Our results indicated that the DNA binder-induced in situ self-assembly of mitochondria can be used to successfully repair ROS-stressed neuron cells. Meanwhile, this DNA binder design is highly programmable. Customized molecular switches can be easily implanted to further achieve stimuli-triggered mitochondrial aggregation and fusion inside living cells. We believe this new type of DNA regulator system will become a powerful chemo-biological tool for subcellular manipulation and precision therapy.

A fully π-conjugated covalent organic framework with dual binding sites for ultrasensitive detection and removal of divalent heavy metal ions.

Covalent organic frameworks (COFs) have become a promising candidate for the remediation of heavy metal pollution. However, researches on COF adsorbents still have challenges on maintaining good optical properties and adsorption performance under harsh conditions. Herein, a fully π-conjugated COF with dual binding sites (Bpy-sp2c-COF) is reported for rapid fluorescence recognition and enhanced adsorption towards divalent heavy metal ions. The vinylene-linkage lattice shows strong luminescence and excellent stability in both strong acidity and basicity. Bpy-sp2c-COF demonstrates not only nanomolar-scale detection of divalent heavy metal ions, but also good adsorption capacity (Hg2+ 718.48, Ni2+ 278.64, Cu2+ 260.11, and Co2+ 126.23 mg/g). Experimental and theoretical studies reveal the intramolecular charge transfer as the fluorescence quenching mechanism. Further simulation results demonstrate the cyano and bipyridine groups on the lattice can act as dual binding sites for divalent heavy metal ions. Experimental results confirmed the adsorption capacity of Bpy-sp2c-COF superior to that of COFs with either cyano groups (Hg2+ 415.34, Ni2+ 165.60, Cu2+ 160.55, and Co2+ 73.14 mg/g), or bipyridine groups (Hg2+ 369.25, Ni2+ 133.41, Cu2+ 133.32, and Co2+ 69.23 mg/g). Besides, robust regeneration of the adsorbent could be achieved over 10 cycles. The fully π-conjugated COF with dual binding sites provides a new approach for designing next-generation sensors and adsorbents with excellent performances.

Effect of divalent cations on electrochemiluminescence of metal-organic frameworks in bioassay.

The structural characteristics of electrochemiluminescent (ECL) microreticula enabled flexible designs for probing specific molecules. However, bioanalysts paid little attention to the impact of concomitant electrolytic carriers on ECL responsiveness of these grids. Our previous finding confirmed the collisional quenching of ECL radiative secondary building units from polarized Br- and I-. To further address this concern, herein typical cationic commonplaces including Na+, K+, Ca2+, … in buffer plus regular transition metals - their influences upon the ECL performance of a well-defined zinc porphyrin-organic framework (ZnPOF) were inspected in a one-by-one manner. Except for Na+/K+, a dozen of divalent metal chlorides exerted an adverse effect in the form of Stern-Volmer quenching on the ECL brightness, which was illuminated to be cation channeling in open voids of ZnPOFs and bonding with O2-reactive sites as exemplified by the model Ca2+ via systematic compositional investigation. Following this principle, a simplistic Ca2+-sensitive sensor was developed for quantitative evaluation of health-care calcium supplements with high precision. Above all, this work highlighted the non-negligible interference from those Mn + requisites to the susceptible MOF-based ECL, which should be paid extra attention in bioassays and mechanistic analyses.

Ligand-binding assay based on microfluidic chemotaxis of porphyrin receptors.

Recent studies have shown that enzymes undergo chemotaxis up substrate gradients during catalysis. One important avenue to identify the molecular level origins of this phenomenon is the ligand-protein binding that occurs even in the absence of catalytic turnover. Here, the chemotaxis of zinc porphyrin as a cofactor mimic was observed by imposing a concentration gradient of organic amines in the microfluidic device. Their axial ligations led to the directed motions of porphyrin receptors. The dissociation constant for selected recognition could be obtained by measuring the chemotactic shift as a function of ligand content, which is associated with both the binding strength and the steric hindrance of the specific ligand. Finally, a statistical thermodynamic model was derived, relating the change of Gibbs free energy (ΔG) in the binding process to the directional migration of receptors. The theoretical model agreed quantitatively with experimental results, elucidating that ΔG of reversible binding essentially drives molecular chemotaxis.

Sorting and Screening of Quaternary Ammonium Lipoids for Membrane-Binding Assays Based on Electrochemiluminescent Cocrystalline Nanosheets.

Being synthetic supplements to natural lipids, lipoids now play an increasingly significant role in nanopore sequencing, olfactory sensing, and nanoimpact electrochemistry. Yet, systematic comparisons to sort and screen qualified lipoids are lacking for specific scenario applications. Here, taking the merits of electrochemiluminescence (ECL) in probing biointerfacial events, a new metric was proposed for the evaluation of substrate candidacy in the pool of hyamine bromides (ABs), that are used to cohere with electron-rich porphyrins for deep eutectics-like ECL matrices. Using a state-of-the-art framework emitter, the cocrystalline nanosheet of C70 and zinc meso-tetraphenylporphine (ZnTPP) via simple liquid-liquid interfacial deposition, 6 out of 20 ABs were inspected and identified as not only amenable filmogens but excitonic sensitizers in key terms of ECL strength as well as voltammetric characteristics. Among them, the methyltrioctyl (MTOAB) headgroup stood out; while the ECL activity at ZnTPP-C70@MTOAB was proven to be dictated by ionophoresis across multilamellar lipoidal layers. Thus, target-induced membrane deformation would let coreactant scavengers in to quench ECL, which enabled assays on two less visited bioprocesses regarding (1) the lipid solubility of ipratropium bromide, an aerosol medication for rhinitis treatment; and (2) the resorption of selenosugar as the central metabolite of Se-proteins on kidney glomerular basement barrier. Both resulted in nice membrane-binding measurements with comparable dissociation constants to reported microfluidic ELISA methods. By and large, though still being rudimentary, such parametrization of ECL-able biofilm would set up a basic ECL toolbox for archiving and resourcing multilipoidal even lipid-lipoid combos to handle the realistic (sub)cytomembrane processes in the future.

Electrochemiluminescent Ion-Channeling Framework for Membrane Binding and Transmembrane Activity Assays.

Recent upgrades in the electrochemiluminescence (ECL) technique showcased its brilliant knack in probing microscopic biointerfacial events, many of which were actually underlain by the ionotropic membrane processes, yet not being ostensive. Here, by modeling an artificial lipoid-supported porin ensemble, we explore and establish the ECL potency in profiling ion-channel activities. A lipophilic hollowed construct dubbed ZnPC was made out of the dynamic covalent chemistry, and its unique geometry was characterized that configured stoichiometric ECL-emissive units in a cubic stance; while the aliphatic vertices of ZnPC helped it safely snorkel and steadily irradiate in a biofilm fusion. After expounding basic ECL properties, the brightness was traced out in response to halogen contents that was lit up by F-/Cl- but down by Br-/I-. The overall pattern fitted the Langmuir isotherm, from which the membrane-binding strengths of the four were analyzed, compared, and collaterally examined in impedimetrics. On the other hand, one could derive anionic transmembrane kinetics from the time-dependent ECL statistics that pinpointed the ECL signaling via the nanocage-directed mass-transfer pathway. More data mining unveiled an ECL-featured Hofmeister series and the thermodynamic governing force behind all scenes. Finally, combining with halide-selective fluorometry, the synthetic conduit was identified as an ECL symporter. In short, this work develops a novel ECL model for the evaluation of life-mimicking membrane permeation. It might intrigue the outreach of ECL applications in the measurement of diverse surface-confined transient scenarios, e.g., in vitro gated ion or molecule trafficking, which used to be handled by nanopore and electrofluorochromic assays.

Bipolar Aggregation-Induced Electrochemiluminescence of Thiophene-Fused Conjugated Microporous Polymers.

Herein, we synthesize the thiophene tetraphenylethene-based conjugated microporous polymer (ThT-CMP) using the tetraphenylethylene derivative [i.e., 1,1,2,2-tetrakis(4-bromophenyl)ethane (TPBE)] and 2,5-thiophenediboronic acid as the precursors. The aggregation of TPBE in the ThT-CMP can induce a strong dual-band bipolar electrochemiluminescence (AIECL) emission at 554 nm (anodic) and 559 nm (cathodic) with tri-n-propylamine (TPrA) and S2O82- as the coreactants, respectively. The anodic and cathodic ECL efficiencies are measured to be 11.49 and 3.82% with respect to the standard of the Ru(bpy)32+/TPrA system, respectively. We further develop a dipolar ECL sensor to sensitively detect rhodamine B (RhB) based on resonance energy transfer. This ECL sensor possesses a large dynamic range and high sensitivity. This research provides a new avenue of designing organic structures with the characteristic of bipolar AIECL for the development of luminescent devices.

Zippering DNA Tetrahedral Hyperlink for Ultrasensitive Electrochemical MicroRNA Detection.

Pluripotency of a DNA tetrahedron (DNATT) has made the iconic framework a compelling keystone in biosensors and biodevices. Herein, distinct from the well-tapped applications in substrate fabrication, we focus on exploring their tracing and signaling potentials. A homologous family of four isostructural DNATT, i.e., DNATTα/ß/γ/δ, was engineered to form a sensor circuitry, in which a target-specific monolayer of thiolated DNATTγ pinned down the analyte jointly with the reciprocal DNATTδ into a sandwich complex; the latter further rallied an in situ interdigital relay of biotinylated DNATTα/ß into a microsized hyperlink dubbed polyDNATT. Its scale and growth factors were illuminated rudimentarily in transmission electron microscopy and confocal laser scanning microscopy. Using a nonsmall-cell lung cancer-related microRNA (hsa-miR-193a-3p) as the subject, a compound DNA-backboned construct was synthesized, fusing all building blocks together. Its superb tacticity and stereochemical conformality avail the templating of a horseradish peroxidase train, which boosted the paralleled catalytic surge of proton donors, resulting in an attomolar detection limit and a broad calibration range of more than seven orders of magnitude. Such oligomerization bested the conventional hybridization chain reaction laddering at both biomechanical stability and stoichiometric congruency. More significantly, it demonstrates the flexibility of DNA architectures and their multitasking ability in biosensing.

Electrochemiluminescence-Repurposed Abiological Catalysts in Full Protein Tag for Ultrasensitive Immunoassay.

Being announced as one of the "2019 Top Ten Emerging Technologies in Chemistry" by IUPAC, the directed evolution of artificial metalloenzymes has led to a broad scope of abiotic processes. Here, inspired by those key proteins in bioluminescence, a rudimentary expression of bio-electrochemiluminescent (ECL) macromolecules was achieved via the complexation of zinc proto-porphyrin IX (ZnPPIX) within apo-hemoglobin (apo-Hb). A high-yield monochromic irradiation at 644 nm could be provoked potentiostatically from the reconstituted holo-HbZnPPIX in solutions. Its secondary structure integrity was elucidated by UV and circular dichroism spectrometry, while voltammetry-hyphenated surface plasmon resonance authenticated its ligation conservativeness in electrical fields. Further conjugation with streptavidin rendered a homogeneous Janus fusion of both receptor and reporter domains, enabling a new abiological catalyst-linked ECL bioassay. On the other hand, singular ZnPPIX inside each tetrameric subunit of Hb accomplished an overall signal amplification without the bother of luminogenic heterojunctions. This pH-tolerant and non-photobleaching optics was essentialized to be the unique configuration interaction between Zn and O2, by which the direct electrochemistry of proteins catalyzed the transient progression of O2 → O2·- → O2* + hυ selectively. Such principle was implemented as a signal-on strategy for the determination of a characteristic cancer biomarker, the vascular endothelial growth factor, resulting in competent performance at a low detection limit of 0.6 pg·mL-1 and a wide calibration range along with good stability and reliability in real practices. This simple mutation repurposed the O2-transport Hb in the erythrocytes of almost all vertebrates into a cluster of oxidoreductases with intrinsic ECL activity, which would enrich the chromophore library. More importantly, its genetically engineered variants may come in handy in biomedical diagnosis and visual electrophysiology.

Terminal-conjugated non-aggregated constraints of gold nanoparticles on lateral flow strips for mobile phone readouts of enrofloxacin.

Antibiotics abuse now poses a global threat to public health. Monitoring their residual levels as well as metabolites are of great importance, still challenges remain in in situ tracing during the circulation. Herein, taking the typical antibacterial Enrofloxacin (ENR) as a subject, a paper-based aptasensor was tailored by manipulating a duo of aptameric moieties to "sandwich" the target in a lateral-flow regime. To visualize the tight-binding sandwich motif more vividly, an irregular yet robust DNA-bridged gold nanoparticles (AuNPs) proximity strategy was developed with recourse to terminal deoxynucleotidyl transferase, of which the nonaggregate constraining feature was unveiled via optical absorption and scanning probe topography. This complex performed exceptionally better in the test strip context than single-particle tags, leading to an enhanced on-chip focusing. Rather than qualitative color developing, further efforts were taken to visualize the readouts in a quantitative manner by exploiting the smartphone camera for pattern recognition along with data processing in a professional App. Overall, this prototyped contraption realized a rapid and ultrasensitive quantification of ENR down to 0.1 µg/L along with a broad linear range over 5 orders of magnitude, plus excellent selectivity and precision even for real samples. Such innovative fusion across DNA-structured nanomanufacturing and intelligent perception provides a prospective and invigorating solution to point-of-care inspection.

Tetraphenylenthene-Based Conjugated Microporous Polymer for Aggregation-Induced Electrochemiluminescence.

We demonstrate the aggregation-induced electrochemiluminescence (AIECL) generated by 1,1,2,2-tetrakis(4-bromophenyl)ethane (TBPE)-based conjugated microporous polymers (TBPE-CMPs) and its biosensing application. We synthesized three TBPE-CMPs (i.e., TBPE-CMP-1, -2, -3) using three different molecules including tris(4-ethynylphenyl)amine (TEPA), 4,4'-diethynylbiphenyl (DEP), and 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine (TEPT). The TBPE-CMPs can act as electrochemiluminescence (ECL) emitters to generate AIECL. Among them, TBPE-CMP-1 exhibits the highest ECL efficiency (1.72%) due to the improved electron-hole recombination efficiency and efficient suppression of nonradiative transition. Moreover, the ECL properties of TBPE-CMPs can be tuned by the introduction of different conjugated molecules that can decrease the energy gap to facilitate the injection of an electron into the conjugated polymer backbone. Importantly, TBPE-CMP-1 can be used to construct an ECL sensor for the detection of dopamine, whose electro-oxidation products (e.g., leucodopaminechrome (LDC), dopaminechrome (DC), 5,6-dihydroxyindole (DHI), and 5,6-indolequinone (IDQ)) may function as energy acceptors to quench the ECL emission of TBPE-CMP-1. This ECL sensor exhibits high sensitivity and good anti-interference capability against ascorbic acid and uric acid.

Porphyrin Trio-Pendant fullerene guest as an In situ universal probe of high ECL efficiency for sensitive miRNA detection.

In this work, pyrrolidyl C60 derivative was recruited as an unadulterated and congruent nano-hub to converge three zinc porphyrins on its monopole. Such peculiar assembly was convinced via micro-imaging and spectrophotometry. Making the best of fullerenyl proficiency in catalytic singlet O2 generation and excited-state preservation, a multiplied electrochemiluminescence (ECL) emission bursted out from the porphyrin trinity in a synergistic manner. Without any prebio-conjugation, this orderly ECL-active individual turned to anchor in the toroid of a peripherally modified gamma-cyclodextrin in a good shape match. From the facile direct mounting of the latter derives a universal bio-probing technique based upon such host-guest inclusion. Its binding pattern and the concomitant effects on interfacial properties were revealed by systematic process characterizations. Taking advantages of this uniform ensemble in both size and stoichiometry, an in situ terminal labelling strategy during the recognition-induced allosteric event came into being, which managed a neat signal enhancement for the detection of model miRNA marker. Even in real samples, the developed sensing approach could achieve high precision, comparable sensitivity and satisfactory selectivity. The adaptation of macrocyclic chemistry for refined biotransducers and efficient ECL amplifiers would offer a generic and potent alternative to the analyte-specified ECL indicator-receptor build in bioassays.

In situ terminus-regulated DNA hydrogelation for ultrasensitive on-chip microRNA assay.

In this work, a dynamic terminus-regulated fabric of DNA hydrogel was invented in debt to the reiterative catalysis of terminal deoxynucleotidyl transferase (TdT). It extended free 3'-OH end to an overhang of homopolymeric adenosine base pair, and alternated with branching from the frayed complementary seed oligo T20G5. The cycle of this template-independent and isothermal amplification resulted in a microscale dendritic DNA fractal at first, which then gelatinized into a cohesive and intricate 3D network. Details of the complex were elucidated with gel electrophoresis, confocal and atomic force microscopy. Its well hydrated inner space could further provide plenty of biocompatible chambers for enzymatic transducers fused along the elongation. Taking merits of this neat and flexible setup, an in situ hydrogelation strategy was developed and utilized in the signal cascade of a miRNA biomarker detector on an electrode microarray, thus accomplished an ultrasensitive, selective and high-throughput sensing even for real samples. This collective manipulation of DNA-protein hydrogel ensemble on interface demonstrates its potency as a general scheme of sensitization in bioanalytical applications.

Chitosan Derived Carbon Matrix Encapsulated CuP2 Nanoparticles for Sodium-Ion Storage.

Sodium-ion batteries (SIBs) are more feasible for grid-scale applications than their lithium-ion counterparts when abundant sodium resources with an even geographic distribution are taken into consideration. However, developing an anode presents a major challenge since the standard graphite anode shows a limited Na-ion storage capacity. Here we report a CuCl2/chitosan monolith derived CuP2/C composite where CuP2 nanoparticles are uniformly embedded in the carbon matrix. The strong chemical bonding between electron rich groups in chitosan and the heavy metal ion (Cu2+) plays a key role for the synthesis of the homogeneous monolithic composite, and chitosan derived carbon prevents Cu and CuP2 particles from aggregation upon the following thermal reduction and phosphorization. Benefiting from the synergistic effect of small particle size and conductive carbon matrix, the CuP2/C composite, as an anode for SIBs, delivers a high reversible capacity of 630 mAh/g at a current density of 100 mA/g and a capacity retention ratio of 91% after 200 cycles, while bare CuP2 shows a rapid capacity decay within 50 cycles.

Enhanced electrochemiluminescent brightness and stability of porphyrins by supramolecular pinning and pinching for sensitive zinc detection.

Ultrasensitive electrochemiluminescence (ECL) detection can benefit substantially from the rational configuration of emitter-enhancer stereochemistry. Here, using zinc(II) meso-5,10,15,20-tetra(4-sulfonatophenyl)porphyrin (ZnTSPP) as a model, we demonstrate that both the ECL intensity and the photostability of this emitter were significantly improved when it was trapped in pyridyl-bridged ß-cyclodextrin dimer (Py(CD)2); a synthetic enhancer that is ECL inactive. Through NMR characterization, we confirmed that ZnTSPP formed a clam-like inclusion complex involving pinning and pinching forces from the biocompatible container Py(CD)2. Up to a threefold increase in the ECL brightness of ZnTSPP was witnessed when it was encapsulated in ß-CD. Absorption and emission spectroscopic data revealed that both the extended excitation lifetime and the restricted mobility of the guest contributed to the observed improvement in signal transduction within the host molecule. This bioinspired entrapment also led to a marked boost in ECL stability. With the aid of the newly identified coreactant H2O2, the hollow TSPP@Py(CD)2 system was employed to create a Zn2+-selective probe that was capable of sensitive and accurate zinc detection. The observed increase in ECL conversion and enhanced photophysical properties of this compact supramolecular assembly render it a novel template for enhancing ECL in analytical applications. Graphical abstract ᅟ.