Detection of CREB phosphorylation via Zr (IV) ion mediated signal amplification

Three-dimensional NiO/Co3O4@C composite for high-performance non-enzymatic glucose sensor

In this study, a new enzyme-free glucose sensor was constructed using the transition metal-based composite material. The synthesis of ZIF-67 entailed the addition of NiO with high catalytic performance. Two-dimensional NiO/Co₃O₄@C heterojunctions were obtained via pyrolysis of NiO@ZIF-67 in the air at a temperature of 500 ℃. The enzyme-free glucose sensor Nafion/NiO/Co₃O₄@C/GCE was constructed by modifying NiO/Co₃O₄@C on a glassy carbon electrode (GCE). The performance of the modified electrode was tested via cyclic voltammetry (CV) and a time-current curve (i-t curve). The linear ranges of the modified electrode were 5 -1000 μM and 1.0- 4.0 mM with sensitivities of 690 and 215.4 μA mM^-1 cm^-2, respectively. The detection limit was 2.28 μΜ (S/N = 3). The recoveries were in the range of 98.9-99.7% during the detection of real samples. The prepared sensor Nafion/NiO/Co₃O₄@C/GCE showed excellent electrocatalytic properties with superb reproducibility, stability and anti-interference capability. The sensor has been successfully utilized to determine glucose in real serum samples.

Zr4+-mediated hybrid chain reaction and its application for highly sensitive electrochemical detection of protein kinase A

An electrochemical platform has been developed to detect protein kinase activity through the combined actions of Zr⁴⁺ mediated signal transition and hybridization chain reaction (HCR)-stimulated DNAzymes nanowires. First of all, protein kinase A (PKA) phosphorylates substrate peptides immobilized on gold electrode surface. Thereafter, the DNA1 containing 5'-phosphoryl ends is linked to the phosphorylated substrate peptide via the robust phosphate-Zr⁴⁺-phosphate linkages. By the introduction of molecular beacons (MBs), the DNA1 can open the hairpin structures of MBs through toehold mediated strand displacement (TMSDR), leading to an autonomous stem-opening process and subsequent assembly of G-quadruplex-containing DNA chains by HCR. After the addition of hemin, the formed HRP-mimicking DNAzymes can catalyze the hydroquinone-H₂O₂ system to generate amplified electrochemical signals. As expected, this method can achieve ultrahigh analytical performance with a low detection limit of 0.02U/mL and exhibit high cost-savings potential without the need for antibody, protease and labeling. Therefore, this method can serve as a new tool for the assay of protein kinase A and its inhibitor screening in the future.

A novel molecular probe for the detection of phosphorylated proteins

The compound ZKY-1 with a D-π-A structure was designed and synthesized in four steps. It undergoes complexation with a tetravalent zirconium ion and the complex can be used for the detection of phosphorylated proteins. The detection limit is estimated to be 100 nmin vitro. The successful detection of phosphorylated proteins in placental tissue samples indicates that this probe holds great potential for clinical diagnosis.

Organic conjugated small molecule materials based optical probe for rapid, colorimetric and UV-vis spectral detection of phosphorylated protein in placental tissue

A novel organic small molecule with D-Pi-A structure was prepared, which was found to be a promising colorimetric and ratiometric UV-vis spetral probe for detection of phosphorylated proteins with the help of tetravalent zirconium ion. Such optical probe based on chromophore WYF-1 shows a rapid response (within 10s) and high selectivity and sensitivity for phosphorylated proteins, giving distinct colorimetric and ratiometric UV-vis changes at 720 and 560nm. The detection limit for phosphorylated proteins was estimated to be 100nM. In addition, detection of phosphorylated proteins in placental tissue samples with this probe was successfully applied, which indicates that this probe holds great potential for phosphorylated proteins detection.

A simple and visible colorimetric method through Zr4+–phosphate coordination for the assay of protein tyrosine phosphatase 1B and screening of its inhibitors

Inhibitors of protein tyrosine phosphatase 1B (PTP1B) are promising agents for the treatment of type 2 diabetes and obesity, so a colorimetric method has been developed in this work for PTP1B assay and screening of its inhibitors.