VIOLET: Visual Analytics for Explainable Quantum Neural Networks.

With the rapid development of Quantum Machine Learning, quantum neural networks (QNN) have experienced great advancement in the past few years, harnessing the advantages of quantum computing to significantly speed up classical machine learning tasks. Despite their increasing popularity, the quantum neural network is quite counter-intuitive and difficult to understand, due to their unique quantum-specific layers (e.g., data encoding and measurement) in their architecture. It prevents QNN users and researchers from effectively understanding its inner workings and exploring the model training status. To fill the research gap, we propose VIOLET, a novel visual analytics approach to improve the explainability of quantum neural networks. Guided by the design requirements distilled from the interviews with domain experts and the literature survey, we developed three visualization views: the Encoder View unveils the process of converting classical input data into quantum states, the Ansatz View reveals the temporal evolution of quantum states in the training process, and the Feature View displays the features a QNN has learned after the training process. Two novel visual designs, i.e., satellite chart and augmented heatmap, are proposed to visually explain the variational parameters and quantum circuit measurements respectively. We evaluate VIOLET through two case studies and in-depth interviews with 12 domain experts. The results demonstrate the effectiveness and usability of VIOLET in helping QNN users and developers intuitively understand and explore quantum neural networks.

Examining Effects of Technique Awareness on the Detection of Remapped Hands in Virtual Reality.

Input remapping techniques have been widely explored to allow users in virtual reality to exceed both their own physical abilities, the limitations of physical space, or to facilitate interactions with real-world objects. Often considered is how these techniques can be applied to achieve maximum utility, but still be undetectable to users to maintain a sense of immersion and presence. Existing psychophysical methods used to determine these detection thresholds have known limitations: they are highly conservative lower bounds for detection and do not account for complex usage of the technique. Our work describes and evaluates a method for estimating detection that reduces these limitations and yields meaningful upper bounds. We present the findings of our work where we apply this method to a well-explored hand motion scaling technique. In wholly unaware cases, we determined that users may detect their hand speed as abnormal at around 3.37 times the normal speed, compared to a scale factor of 1.47 that was estimated using traditional methods when users knew the motion scaling was occurring. A considerable number of participants in unaware cases (12 of 56) never detected their hand speed increasing at all, even at the maximum scale factor of 5.0. The study demonstrates just how conservative the thresholds generated by traditional psychophysical methods can be compared to detection during naive usage, and our method can be modified and applied easily to other techniques.

InkSight: Leveraging Sketch Interaction for Documenting Chart Findings in Computational Notebooks.

Computational notebooks have become increasingly popular for exploratory data analysis due to their ability to support data exploration and explanation within a single document. Effective documentation for explaining chart findings during the exploration process is essential as it helps recall and share data analysis. However, documenting chart findings remains a challenge due to its time-consuming and tedious nature. While existing automatic methods alleviate some of the burden on users, they often fail to cater to users' specific interests. In response to these limitations, we present InkSight, a mixed-initiative computational notebook plugin that generates finding documentation based on the user's intent. InkSight allows users to express their intent in specific data subsets through sketching atop visualizations intuitively. To facilitate this, we designed two types of sketches, i.e., open-path and closed-path sketch. Upon receiving a user's sketch, InkSight identifies the sketch type and corresponding selected data items. Subsequently, it filters data fact types based on the sketch and selected data items before employing existing automatic data fact recommendation algorithms to infer data facts. Using large language models (GPT-3.5), InkSight converts data facts into effective natural language documentation. Users can conveniently fine-tune the generated documentation within InkSight. A user study with 12 participants demonstrated the usability and effectiveness of InkSight in expressing user intent and facilitating chart finding documentation.

Evaluation of intracellular lipid droplets viscosity by a probe with high fluorescence quantum yield.

BACKGROUND: Lipid droplets (LDs) are an important organelle as the main energy storage site in cells. LDs viscosity controls the material and energy exchange between it and other organelles. Furthermore, the LDs metabolic abnormalities, cell dysfunction, some diseases may be attributed to the singular LDs viscosity. Currently, the fluorescent probes for sensing the variations of LDs viscosity are still scarce and expose some drawbacks of low fluorescence quantum yield, low sensitivity and LDs polarity interference. Thus, the development of high performance probes is significant to detect LDs viscosity. RESULTS: We hereby provide a lipophilic fluorescent probe (TPE-BET) with high fluorescence quantum yield (Φf, 0.91 in glycerol) for imaging LDs viscosity in living cells. With the increase of viscosity from 0.54 cp to 934 cp, the fluorescence at λex/λem = 405/520 nm and the fluorescence quantum yield of TPE-BET linearly increased by 64.9 and 128.5 folds, respectively. Meanwhile, the outstanding LDs staining capability of TPE-BET may provide a high spatial resolution for LDs imaging. The cell imaging of TPE-BET not only successfully observed the viscosity variations of LDs in cell stress models, e.g., ferroptosis, inflammation and mitophagy, but also revealed the increased viscosity and extracellular delivery of LDs in heavy metal cell injury models (Hg/As) for the first time, which may supply concrete evidence for understanding the structure and function of LDs. SIGNIFICANCE: This represents a new fluorescent probe TPE-BET with high fluorescence quantum yield for imaging LDs viscosity, which may decrease the dose of probe and excitation light intensity along with the improvement on signal noise ratio (S/N). The imaging results of TPE-BET clarified that LDs viscosity may be an appraisal index on cell differentiation, state evaluation and drug screening.

DMiner: Dashboard Design Mining and Recommendation.

Dashboards, which comprise multiple views on a single display, help analyze and communicate multiple perspectives of data simultaneously. However, creating effective and elegant dashboards is challenging since it requires careful and logical arrangement and coordination of multiple visualizations. To solve the problem, we propose a data-driven approach for mining design rules from dashboards and automating dashboard organization. Specifically, we focus on two prominent aspects of the organization: arrangement, which describes the position, size, and layout of each view in the display space; and coordination, which indicates the interaction between pairwise views. We build a new dataset containing 854 dashboards crawled online, and develop feature engineering methods for describing the single views and view-wise relationships in terms of data, encoding, layout, and interactions. Further, we identify design rules among those features and develop a recommender for dashboard design. We demonstrate the usefulness of DMiner through an expert study and a user study. The expert study shows that our extracted design rules are reasonable and conform to the design practice of experts. Moreover, a comparative user study shows that our recommender could help automate dashboard organization and reach human-level performance. In summary, our work offers a promising starting point for design mining visualizations to build recommenders.

Photoreversible DNA nanoswitch-based eluent-free strategy for the direct and effective isolation of highly-active thrombin from whole blood.

This study proposes an eluent-free isolation strategy for the direct isolation of thrombin from whole blood via tandem temperature/pH dual-responsive polyether sulfone monolith and photoreversible DNA nanoswitch-functionalized metal-organic framework (MOF) aerogel. Temperature/pH dual-responsive microgel immobilized on polyether sulfone monolith was adopted to remove the matrix complexity of blood sample via size/charge screening effect. Photoreversible DNA nanoswitches, comprising thrombin aptamer, aptamer complementary ssDNA (cDNA) and the azobenzene-modified ssDNA (control DNA), were functionalized on MOF aerogel to offer efficient capturing of thrombin under irradiation of ultraviolet light (365 nm), driven by electrostatic and hydrogen bond interactions. The release of captured thrombin was easily achieved by changing the complementary behaviors of DNA strands via blue light (450 nm) irradiation. Thrombin with purity higher than 95 % can be directly obtained from whole blood using this tandem isolation procedure. Fibrin production and substrate chromogenic tests showed that the released thrombin possessed high biological activity. The photoreversible thrombin capturing-release strategy is merited with eluent-free, avoiding the loss of activity of thrombin in chemical circumstances and undesired dilution, providing a robust guarantee for subsequent application.

Rational synthesis of carbon dots with phosphate ester group for direct mapping of endogenous alkaline phosphatase and polarity monitoring in living cells.

Carbon dots (CDs) have been extensively employed in biomolecule imaging. However, the imaging of biological enzymes with CDs has not been reported, which greatly limits their application in biological imaging. Herein, for the first time, a new type of fluorescent CDs is elaborately designed to realize the direct mapping of alkaline phosphatase (ALP) in cells. The obtained phosphorus and nitrogen co-doped CDs (P, N-CDs) generate specific structures including xanthene oxide and phosphate ester, thereby enabling P, N-CDs to be exclusively cleaved by ALP without auxiliary media. The fluorescence intensity of P, N-CDs can be specifically turned on in the presence of ALP, making them powerful probes for sensitive sensing of ALP activity with a detection limit of 1.27 U·L-1. Meanwhile, P, N-CDs possessing electron deficiency structure fulfill sensitive responding to polarity variations. The excellent photo-bleaching resistance and biocompatibility of the P, N-CDs are taken for directly mapping the intracellular endogenous ALP via turned-on fluorescence imaging, as well as real-time monitoring the polarity fluctuation in cells through ratiometric fluorescence imaging. The present work offers a new way to design and synthesize functional CDs for direct imaging of intracellular enzymes.

VBridge: Connecting the Dots Between Features and Data to Explain Healthcare Models.

Machine learning (ML) is increasingly applied to Electronic Health Records (EHRs) to solve clinical prediction tasks. Although many ML models perform promisingly, issues with model transparency and interpretability limit their adoption in clinical practice. Directly using existing explainable ML techniques in clinical settings can be challenging. Through literature surveys and collaborations with six clinicians with an average of 17 years of clinical experience, we identified three key challenges, including clinicians' unfamiliarity with ML features, lack of contextual information, and the need for cohort-level evidence. Following an iterative design process, we further designed and developed VBridge, a visual analytics tool that seamlessly incorporates ML explanations into clinicians' decision-making workflow. The system includes a novel hierarchical display of contribution-based feature explanations and enriched interactions that connect the dots between ML features, explanations, and data. We demonstrated the effectiveness of VBridge through two case studies and expert interviews with four clinicians, showing that visually associating model explanations with patients' situational records can help clinicians better interpret and use model predictions when making clinician decisions. We further derived a list of design implications for developing future explainable ML tools to support clinical decision-making.

Functionalized polyoxometalate microspheres ensure selective adsorption of phosphoproteins and glycoproteins.

Lacunary polyoxometalate (POM), [PW9O34]9-, grafts with a boronic acid group attached via an organosilane bridge assemble into microspheres, PW9-Si-APBA. The oxygen-rich and hydrophilic surface of POM facilitates the binding of phosphate groups in phosphoproteins and glycans in glycoproteins. While the metal-oxo in POM provides π-π interactions with the phosphate groups of phosphoproteins, the boronic acid group specifically binds to glycoproteins via the cis-diols of glycans. Therefore, these multi-driving forces ensure the selective adsorption of phosphoproteins and glycoproteins by PW9-Si-APBA microspheres in biological sample matrixes, even in the presence of very high protein abundance, i.e., BSA, at mass ratio of ß-ca/IgG/OVA/BSA = 1 : 1 : 1 : 200.

Composition and Configuration Patterns in Multiple-View Visualizations.

Multiple-view visualization (MV) is a layout design technique often employed to help users see a large number of data attributes and values in a single cohesive representation. Because of its generalizability, the MV design has been widely adopted by the visualization community to help users examine and interact with large, complex, and high-dimensional data. However, although ubiquitous, there has been little work to categorize and analyze MVs in order to better understand its design space. As a result, there has been little to no guideline in how to use the MV design effectively. In this paper, we present an in-depth study of how MVs are designed in practice. We focus on two fundamental measures of multiple-view patterns: composition, which quantifies what view types and how many are there; and configuration, which characterizes spatial arrangement of view layouts in the display space. We build a new dataset containing 360 images of MVs collected from IEEE VIS, EuroVis, and PacificVis publications 2011 to 2019, and make fine-grained annotations of view types and layouts for these visualization images. From this data we conduct composition and configuration analyses using quantitative metrics of term frequency and layout topology. We identify common practices around MVs, including relationship of view types, popular view layouts, and correlation between view types and layouts. We combine the findings into a MV recommendation system, providing interactive tools to explore the design space, and support example-based design.

A chemiluminescence assay for determination of lysozyme based on the use of magnetic alginate-aptamer composition and hemin@HKUST-1.

Lysozyme aptamer-functionalized magnetic alginate hydrogel was prepared for separation and enrichment of lysozyme. Luminol-labeled aptamer was used as a signal tag, and the signal tag was adsorbed on magnetic carboxylated carbon nanotubes based on the π-interaction. When lysozyme was added, the aptamer specifically binds to the lysozyme, causing the signal tag to detach from the magnetic carboxylated carbon nanotubes. When the aptamer/lysozyme complex bound to the complementary single strand of aptamer on the hemin@HKUST-1, lysozyme was released. The released lysozyme can be recombined with the signal tag adsorbed on the magnetic carboxylated carbon nanotube, allowing more signal tag to be dispersed into the solution. Determination of lysozyme was achieved by releasing the luminol-labeled aptamer to generate a chemiluminescence signal at a wavelength of 425 nm. It was proved by experiments that the synthesized hemin@HKUST-1 had a strong catalytic effect on the luminol-NaOH-H2O2 system. The chemiluminescence signal was increased nearly 100 times. The complementary pairing allowed the luminol to be immobilized on the surface of hemin@HKUST-1. The generation and consumption of short-lived reactive oxygen species were concentrated on the surface of the MOFs, which improves the chemiluminescence efficiency. The introduction of hemin@HKUST-1 and DNA solved the defects of chemiluminescence analysis. The chemiluminescence assay was able to detect lysozyme with linear range of 1.05 × 10-6 U∙mg-1 (6.00 × 10-13 mol∙L-1)-1.25 × 10-2 U∙mg-1 (7.14 × 10-9 mol∙L-1); the detection limit was 3.50 × 10-7 U∙mg-1 (2.00 × 10-13 mol∙L-1) (R2 = 0.99). The recovery of lysozyme in spiked saliva samples was 97.4-102.8%. Graphical abstract Schematic presentation of chemiluminescence assay. Lysozyme (Lys) was captured by aptamer-modified magnetic sodium alginate (M-Alg-Apt); Glycine (pH = 2) as eluent for Lys. Luminol-modified Apt (Apt-luminol) as signal tag; magnetic carbon nanotubes (MCNTs) as adsorption matrix; cDNA was complementary to Apt; hemin@HKUST-1 as catalyst.

A "signal-on" chemiluminescence biosensor for thrombin detection based on DNA functionalized magnetic sodium alginate hydrogel and metalloporphyrinic metal-organic framework nanosheets.

A "signal-on" chemiluminescence biosensor was established for detecting thrombin. The thrombin aptamer1-functionalized magnetic sodium alginate (Malg-Apt1) hydrogel was synthesized by physical interaction between sodium alginate and Ca2+, and it was used in the biosensor for separating and enriching thrombin. Ethylenediamine tetraacetic acid (EDTA) was used to chelate with Ca2+ to dissolve the hydrogel and release thrombin. A metalloporphyrinic metal-organic framework nanosheet, named as Cu-TCPP(Co) MOFs, was prepared as signal amplification strategy. Cu-TCPP(Co) MOFs/Au-ssDNA (ssDNA: single-strand DNA) was synthesized for controllable further amplification of chemiluminescent signal. The thrombin aptamer2-functionalized magnetic carbon nanotubes (MCNTs-Apt2) were used as a matrix, and Cu-TCPP(Co) MOFs/Au-ssDNA was adsorbed on the MCNTs by the complementary pairing of the partial bases between ssDNA and Apt2. Compared with ssDNA, Apt2 has a stronger interaction with thrombin. Therefore, thrombin can trigger the release of Cu-TCPP(Co) MOFs/Au-ssDNA to achieve signal amplification. Under the optimal conditions, the biosensor could detect thrombin as low as 2.178 × 10-13 mol/L with the range from 8.934 × 10-13 to 5.956 × 10-10 mol/L and exhibited excellent selectively. Moreover, the "signal-on" chemiluminescence biosensor showed potential application for the detection of thrombin in body fluids.

Rapid fabrication of electrode for the detection of alpha fetoprotein based on MnO2 functionalized mesoporous carbon hollow sphere.

The concentration of alpha-fetoprotein (AFP) rises greatly in patients with liver cancer and it is a challenge to construct a sensitive AFP detection method with wide range. Therefore, an easy and label-free sensing electrochemical platform for AFP detection with wide concentration range had been designed in this work. Firstly, MnO2 functionalized mesoporous carbon hollow sphere (MCHS@MnO2) with optimal performance was synthesized by regulating experimental conditions and characterized by scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV), etc. Then, it was immobilized on glassy carbon electrode (MCHS@MnO2/GCE) to build an immunosensor for the detection of AFP. The MCHS@MnO2/GCE can catalyze decomposition of H2O2 to generate electrochemical signal, and the signal will decrease after capturing AFP. Due to good electrocatalytic activity of MCHS@MnO2 to H2O2, the immunosensor achieved indirect detection of AFP with wide sensing range from 0.10 ng mL-1 to 420 ng mL-1 and a detection limit of 0.03 ng mL-1. Furthermore, the method had been proven to be satisfactory selectivity and reproducibility, and it was successfully applied to determine the content of AFP in human serum samples with satisfactory results. This method is expected to be used for early diagnosis and prognosis examination of liver cancer patients.

A highly selective and sensitive detection of insulin with chemiluminescence biosensor based on aptamer and oligonucleotide-AuNPs functionalized nanosilica @ graphene oxide aerogel.

A novel, highly selective and sensitive chemiluminescence (CL) biosensor for insulin (INS) detection was proposed based on aptamer and oligonucleotide-gold nanoparticles functionalized nanosilica @ graphene oxide aerogel. Initially, nanosilica functionalized graphene oxide aerogel (SiO2@GOAG) was successfully prepared and the composite showed rich pore distribution, large specific surface area and good biocompatibility. Insulin aptamer (IGA3) was used as a biorecognition element and oligonucleotide functionalized gold nanoparticles (ssDNA-AuNPs) was used as CL signal amplification materials, which were functionalized on the surface of SiO2@GOAG. The multi-functionalized composite - ssDNA-AuNPs/IGA3/SiO2@ GOAG was obtained and used to construct the CL biosensor for insulin detection. When insulin is present in a sample, the insulin will bind to the IGA3, which will result in the release of ssDNA-AuNPs. The released ssDNA-AuNPs would catalyze the luminescence of luminol and H2O2. The linear range of the CL biosensor for insulin detection was 7.5 × 10-12 to 5.0 × 10-9 moL/L and the detection limit was 1.6 × 10-12 moL/L (S/N = 3). The selectivity and stability of the CL biosensor were also studied and the results showed that the biosensor exhibited high selectivity and good stability due to the introduction of ssDNA-AuNPs/IGA3/SiO2@GOAG. The CL biosensor was finally used for recombinant human insulin detection in recombinant human insulin injection and the results were satisfactory.

A chemiluminescence biosensor for lysozyme detection based on aptamers and hemin/G-quadruplex DNAzyme modified sandwich-rod carbon fiber composite.

In our work, aptamers and hemin/G-quadruplex DNAzyme modified sandwich-rod graphene quantum dots @ graphene oxide @ carbon fiber composite (DNAzyme/L-Apt/GQDs@GO@CF) was successfully prepared for sensitive and selective chemiluminescence (CL) detection of lysozyme (LZM). Initially, GQDs@GO@CF was successfully prepared and characterized. Lysozyme aptamers (L-Apt) as a recognition element and hemin/G-quadruplex DNAzyme (DNAzyme) as a catalyst of luminal - H2O2 were modified on the surface of GQDs@GO@CF, sequentially. The immobilization properties of GQDs@GO@CF to L-Apt and the adsorption properties of L-Apt/GQDs@GO@CF to DNAzyme were also researched, respectively. Then, the modified sandwich-rod carbon fiber composite was applied to the construction of CL biosensor for LZM detection. When LZM existed, DNAzyme would be released from the surface of L-Apt/GQDs@GO@CF and catalyzed the reaction of luminal - H2O2. Under optimized conditions, the CL biosensor for LZM detection showed wide linear range of 2.64 × 10-10 to 6.6 × 10-8 g/L and low detection limit of 1.25 × 10-11 g/L (3δ). Finally, the CL biosensor was successfully used for LZM detection in human urine samples and illustrated the potential application in pratical samples.

Injury to the axillary artery and brachial plexus caused by a closed floating shoulder injury: A case report.

BACKGROUND: A floating shoulder may be associated with catastrophic neurovascular injury and requires a multidisciplinary approach for its management. To maximize the likelihood of good patient outcomes, this unique injury pattern should be recognized in patients as early as possible. This can be difficult to achieve, however, as there are currently few reports of floating shoulder in the literature, meaning that associated neurovascular injuries may be overlooked. CASE SUMMARY: We present here a rare case of floating shoulder with axillary artery injury in a 34-year-old woman. The patient complained of pain and numbness of her left upper limb after losing control of her motorcycle on a highway and falling from the vehicle 2 h ago. No blood pressure reading could be obtained from her left upper limb and no blood oxygen readings could be obtained from any of her left fingers. Computed tomography angiography and duplex ultrasonography revealed interruption of blood flow through the axillary artery, with distal flow being maintained through collateral arteries. The clinical diagnosis including fracture of the left proximal humerus, the left clavicle, and the left scapula, left axillary artery rupture, and left brachial plexus injury. We successfully performed open reduction and internal fixation of the fracture and vascular repair. The patient showed satisfactory recovery that was observed during 4-mo follow-up. CONCLUSION: Emergency surgery can be an effective therapeutic option for the closed floating shoulder with catastrophic axillary artery injury.

A chemiluminescence aptasensor for thrombin detection based on aptamer-conjugated and hemin/G-quadruplex DNAzyme signal-amplified carbon fiber composite.

In this work, a highly sensitive and selective chemiluminescence (CL) aptasensor was prepared for thrombin (THR) detection based on aptamer-conjugated and hemin/G-quadruplex DNAzyme signal-amplified carbon fiber composite (HG-DNAzyme/T-Apt/SiO2@GO@CF). Initially, SiO2@GO@CF was successfully prepared and characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Thrombin aptamer (T-Apt) as an identification element and simulated enzyme - hemin/G-quadruplex DNAzyme (HG-DNAzyme) as a signal-amplified material, were applied in the CL aptasensor. Then, the immobilization properties of SiO2@GO@CF and adsorption properties of T-Apt/SiO2@GO@CF were studied. Lastly, HG-DNAzyme/T-Apt/SiO2@GO@CF was applied in construction of the CL aptasensor. When THR existed, HG-DNAzyme was desorbed from the surface of T-Apt/SiO2@GO@CF and catalyzed the CL system of luminol-H2O2. Under optimized CL conditions, THR was measured with the linear concentration range of 1.5 × 10-14 to 2.5 × 10-11 moL/L and the detection limit of 6.3 × 10-15 moL/L (3δ). The proposed CL aptasensor was used to the determination of THR in human serum samples and recoveries ranged from 99.0% to 102.4%. Those satisfactory results illustrated the CL aptasensor could achieve highly sensitive and selective detection of THR and revealed potential application in practical samples.

Highly selective and sensitive chemiluminescence biosensor for adenosine detection based on carbon quantum dots catalyzing luminescence released from aptamers functionalized graphene@magnetic ß-cyclodextrin polymers.

In this work, a highly selective and sensitive chemiluminescence (CL) biosensor was prepared for adenosine (AD) detection based on carbon quantum dots (CQDs) catalyzing the CL system of luminol-H2O2 under alkaline environment and CQDs was released from the surface of AD aptamers functionalized graphene @ magnetic ß-cyclodextrin polymers (GO@Fe3O4@ß-CD@A-Apt). Firstly, GO@Fe3O4@ß-CD and CQDs were prepared and characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), UV-Vis absorption spectra (UV), fluorescence spectra (FL), fourier transform infrared (FTIR) and X-ray powder diffraction (XRD). For GO@Fe3O4@ß-CD, Fe3O4 was easy to separate, GO had good biocompatibility and large specific surface area, and ß-CD further increased the specific surface area of the adenosine polymers (A-Apt) to provided larger binding sites to A-Apt. Then, A-Apt was modified on the surface of GO@Fe3O4@ß-CD while CQDs was modified by ssDNA (a single stranded DNA partially complementary to A-Apt). The immobilization property (GO@Fe3O4@ß-CD to A-Apt) and the adsorption property (GO@Fe3O4@ß-CD@A-Apt to CQDs-ssDNA) were sequentially researched. The base-supported chain-like polymers - GO@Fe3O4@ß-CD@A-Apt/CQDs-ssDNA was successfully obtained. When AD existed, CQDs-ssDNA was released from the surface of GO@Fe3O4@ß-CD@A-Apt and catalyzed CL. After that, under optimized CL conditions, AD could be measured with the linear concentration range of 5.0 × 10-13-5.0 × 10-9 mol/L and the detection limit of 2.1 × 10-13 mol/L (3δ) while the relative standard deviation (RSD) was 1.4%. Finally, the GO@Fe3O4@ß-CD@A-Apt/CQDs-ssDNA-CL biosensor was used for the determination of AD in urine samples and recoveries ranged from 98.6% to 101.0%. Those satisfactory results illustrated the proposed CL biosensor could achieve highly selective, sensitive and reliable detection of AD and revealed potential application for AD detection in monitoring and diagnosis of human cancers.

Morphology-dependent electrochemical behavior of 18-facet Cu7S4 nanocrystals based electrochemical sensing platform for hydrogen peroxide and prostate specific antigen.

18-facet polyhedron Cu7S4 nanocrystal and CuS sphere were prepared from Cu2O precursor, and CuS flower was synthesized through a simple solvothermal approach. Their electrochemical performances were investigated towards H2O2 and it was interesting to discover that Cu7S4 nanocrystal had the best electrochemical catalysis compared with CuS sphere and CuS flower. It can deduce that the special structure of Cu7S4 nanocrystal endowed it more exposed active points, higher surface area and higher Cu/S ratio. Therefore, Cu7S4 nanocrystal was firstly employed to prepare a nonenzymatic biosensor for H2O2. Satisfactory results were obtained. In addition, a label-free sensing platform for prostate specific antigen (PSA) was constructed based on electrochemical catalysis towards H2O2 of Cu7S4 nanocrystal. The label-free immunosenosr offered accurate PSA in the range of 0.001-15 ng/mL with the detection limit of 0.001 ng/mL. Besides, the immunosensor possessed good sensitivity, selectivity and stability and could detect PSA in real sample. More importantly, this work demonstrated that Cu7S4 nanocrystal hold great promising application in electrochemical sensors.

A turn-on chemiluminescence biosensor for selective and sensitive detection of adenosine based on HKUST-1 and QDs-luminol-aptamer conjugates.

In this work, HKUST-1 and QDs-luminol-aptamer conjugates were prepared. The QDs-luminol-aptamer conjugates can be adsorbed by graphene oxide through π-π conjugation. When the adenosine was added, the QDs-luminol-aptamer conjugates were released from magnetic graphene oxide (MGO), the chemiluminescent switch was turned on. It was reported that HKUST-1 can catalyze the chemiluminescence reaction of luminol-H2O2 system in an alkaline medium, and improve the chemiluminescence resonance energy transfer (CRET) between chemiluminescence and QDs indirectly. Thus, the adenosine can be detected sensitively. Based on this phenomenon, the excellent platform for detection of adenosine was established. Under the optimized conditions, the linear detection range for adenosine was 1.0 × 10-12-2.2 × 10-10 mol/L with a detection limit of 2.1 × 10-13 mol/L. The proposed method was successfully used for adenosine detection in biological samples.