Mussel-inspired functionalization of electrochemically exfoliated graphene: Based on self-polymerization of dopamine and its suppression effect on the fire hazards and smoke toxicity of thermoplastic polyurethane.

Exosomes are nanoscale extracellular vesicles and have proven to be an effective biomarker for early cancer diagnosis. In this work, an ECL and photothermal dual-mode biosensor was fabricated for exosomes detection by utilizing emerging materials black phosphorous quantum dots (BPQDs) and MXenes as signal amplifier. To be specific, BPQDs can catalyze the oxidization of Ru(dcbpy)32+ and was for the first time used as coreactant, the prepared self-enhanced Ru(dcbpy)32+@BPQDs ECL system can produce a strong ECL signal by reducing energy loss and shortening electron transfer distance. MXenes possess large specific surface area and outstanding conductivity, which was employed as supporter to increase the immobilization amount of Ru(dcbpy)32+ and BPQDs, further enhanced ECL signal. Furthermore, BPQDs and MXenes both have excellent photothermal effect, which were dexterously used as thermal convertor device to develop photothermal biosensor for exosomes analysis. This work innovatively employed a dual-modality probe of MXenes-BPQDs to establish biosensor, which not only enriched the application of MXenes and BPQDs in biodetection but also provided an effective and reliable method for exosomes detection.

Black phosphorus quantum dots functionalized MXenes as the enhanced dual-mode probe for exosomes sensing

Engineered nanomaterials continue to stimulate wide interest in diverse disciplines including electrochemistry. Particularly, rare-earth-metal vanadate (REVO) is widely applied in the development o...

Rational Design for the Synthesis of Europium Vanadate-Encapsulated Graphene Oxide Nanocomposite: An Excellent and Efficient Catalyst for the Electrochemical Detection of Clioquinol

Two-dimensional layered nanomaterial Ti3C2TX (a member of the MXene family) was used to immobilise enzyme sarcosine oxidase to fabricate a nanostructured biosensor. The device was applied for detection of sarcosine, a potential prostate cancer biomarker, in urine for the first time. The morphology and structures of MXene have been characterised by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrochemical measurements, SEM and AFM analysis revealed that MXene interfaced with chitosan is an excellent support for enzyme immobilisation to fabricate a sensitive biosensor exhibiting a low detection limit of 18 nM and a linear range up to 7.8 µM. The proposed biosensing method also provides a short response time of 2 s and high recovery index of 102.6% for detection of sarcosine spiked into urine sample in a clinically relevant range.

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Ultrasensitive Ti3C2TX MXene/Chitosan Nanocomposite-Based Amperometric Biosensor for Detection of Potential Prostate Cancer Marker in Urine Samples

Identifying biomolecules for disease diagnosis requires simple, accurate, and reliable analytical techniques. Multiple signal transduction pathways have promoted the development of various biological analysis systems. However, most systems are largely limited by a single mechanism or model analysis, which can easily lead to false-positive/negative results. Herein, we report a covalent organic framework (COF) (TpPa-1) functionalized with a dye (fluorescein sodium) and design this hybrid material (TpPa-1@Dye) to fabricate hydrogels for subsequent analysis with the indicator displacement assay (IDA) method. Selecting a suitable metal cation (Cr3+) for the preparation of hydrogels can reduce the background fluorescence, improve the detection sensitivity, and increase the corresponding sensing selectivity. The TpPa-1@Dye functions as an indicator in the IDA-in-COF system, and Cr3+ is a receptor of the analyte (sialic acid (SA), a biomarker for ovarian cancer diagnosis). Based on the above studies, the integrative logic operations (AND + IMP) are further established, it helps in elucidating the design rules of the IDA-in-COF approach. This work represents the first effort in designing IDA-in-COF luminescent sensors with an On-Off-On mechanism to determine biomarkers and provides a new approach for developing hybrid COF luminescent materials as analysis platforms for human health monitoring.

Indicator Displacement Assay Inside Dye-Functionalized Covalent Organic Frameworks for Ultrasensitive Monitoring of Sialic Acid, an Ovarian Cancer Biomarker.

A non-enzymatic electrochemical sensor for detection of sialic acid based on a porphine/graphene oxide modified electrode via indicator displacement assay

A Graphene Oxide‐DNA Electrochemical Sensor Based on Glassy Carbon Electrode for Sensitive Determination of Methotrexate

A simple ultrasensitive electrochemical sensor for simultaneous determination of homovanillic acid and vanillylmandelic acid in human urine based on MWCNTs-Pt nanoparticles as peroxidase mimics

A nonenzymatic electrochemical sensor is described for the prostate cancer biomarker sarcosine (Sar). Riboflavin was employed to mimic the active center of the enzyme sarcosine oxidase for constructing the biomimetic sensor. The use of riboflavon (Rf) avoids the disadvantages of an enzymatic sensor, such as high cost and poor stability. A glassy carbon electrode (GCE) was modified with a graphene-chitosan (GR) composite and further modified with gold-platinum bimetallic nanoparticles in a polypyrrole (PPy) matrix in order to enhance the catalytic activity of the enzyme mimic. Finally, Rf was electrodeposited on the surface of the AuPt-PPy/GR-modified GCE. Under optimized conditions, the GCE provided high sensitivity and selectivity for Sar at around 0.61 V. Response covers the 2.5–600 μM concentration range, and the detection limit is 0.68 μM. The method was successfully applied to the determination of Sar in spiked urine with 98.0%–103.2% recovery.

An electrochemical sarcosine sensor based on biomimetic recognition

Sulfur-containing materials with high affinity toward heavy metals have recently aroused great research enthusiasm. Yet the removal differences and mechanisms for various heavy metals remain unclear in view of rarely systematical reports. In this regard, a sulfate-loaded adsorbent ([email protected]) synthesized by precursor-calcination strategy was employed for investigating the removal differences of heavy metals (i.e., Pb(Ⅱ), Cd(Ⅱ) and Ni(Ⅱ), typical heavy metals in wastewater). As predicted, a diverse adsorption capability for metals on [email protected] was observed, following the order of Pb(Ⅱ) (631.90 mg g−1) > Cd(Ⅱ) (208.27 mg g−1) > Ni(Ⅱ) (119.02 mg g−1). Both adsorption isotherm and kinetic demonstrated that the monolayer, heterogeneous-homogeneous, and multilayer adsorption occurred in Pb(Ⅱ), Cd(Ⅱ) and Ni(Ⅱ), respectively, which were controlled by chemisorption. Furthermore, the removal differences were deeply exploded via the combination of XRD, FT-IR and XPS analyses and contribution calculation. The ion exchange was the main adsorption mechanisms for Pb (II) with 44.77%, while complexation dominated in Cd(II) and Ni(II) removal, with the proportion of 53.36% and 55.89%, respectively. Besides, the solubility constant (Ksp) of precipitate, affinity of sulfate group, as well as the self-characteristic properties contributed to various removal ability for heavy metal ions (e.g., ionic radius, electronegativity, and hard-soft-acid-base attribute) as well. 

Jincheng Chen

Papers

A non-enzymatic electrochemical sensor for detection of sialic acid based on a porphine/graphene oxide modified electrode via indicator displacement assay

A Graphene Oxide‐DNA Electrochemical Sensor Based on Glassy Carbon Electrode for Sensitive Determination of Methotrexate

A simple ultrasensitive electrochemical sensor for simultaneous determination of homovanillic acid and vanillylmandelic acid in human urine based on MWCNTs-Pt nanoparticles as peroxidase mimics

An electrochemical sarcosine sensor based on biomimetic recognition

Insight into different removal behaviors and mechanism of heavy metals via sulfate-loaded layered double oxide