Cucurbit[n]uril (n = 6, 7) Based Carbon-Gold Hybrids with Peroxidase-Like Activity

Nanocomposite of Peroxidase-Like Cucurbit[6]uril with Enzyme-Encapsulated ZIF-8 and Application for Colorimetric Biosensing

In this work, cucurbiturils (CBs), a class of macrocyclic supramolecules, were observed to have an interesting peroxidase-like activity, which is metal-free, substrate-specific, thermophilic, acidophilic, and insensitive to ionic strength. By coating CBs on enzyme-encapsulated zeolitic imidazolate framework-8 (ZIF-8), a composite nanozyme was constructed, which retains the catalytic ability of CBs and enzymes and makes them cascade. On addition of the substrate, i.e., the detection target, a highly efficient cascade catalysis can be launched in all the spatial directions to generate sensitive and visible signals. Convenient detection of glucose and cholesterol as models is thereby achieved. More importantly, we have also successfully constructed a composite nanozyme-based sensor array (6 × 8 wells) and thereby achieved simultaneous colorimetric analysis of multiple samples. The concept and successful practice of the construction of the unique core-shell supramolecule/biomolecule@nanomaterial architecture provide the possibility to fabricate next-generation multifunctional materials and create new applications by integrating their unique functions.

One-Pot Hydrothermal Synthesis of Carbon Quantum Dots with Excellent Photoluminescent Properties and Catalytic Activity from Coke Powders

Water-soluble, high quantum yield, green color carbon quantum dots (CQDs) are prepared by acid reflux with the use of coke powders as a carbon source. The CQDs are characterized by UV-Vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscope, fourier transform infrared spectrophotometer and x-ray diffraction. The analysis includes the evaluation of key variables with effect in the synthetic process of the quantum yield (QY) of CQDs: the reaction temperature and time, the volume of mixed acid (concentrated H₂SO₄ and HNO₃) and the pH value on the structure and properties of as-prepared CQDs. The results revealed that the optimal hydrothermal synthesis conditions for obtaining CQDs are reaction at 100 °C for 8 h, with the volume of mixed acid is 16 mL, at pH value 9. The prepared CQDs have the activity of peroxidase-like and that quantum yield(QY)reached 34.27%.