Fen-Fen Zhang

ZnS quantum dots derived a reagentless uric acid biosensor

A reagentless amperometric uric acid biosensor based on zinc sulfide (ZnS) quantum dots (QDs) was firstly developed. It could detect uric acid without the presence of an electron mediator. The carboxyl group functionalized ZnS QDs were synthesized, and they were soluble biocompatible and conductive. ZnS QDs conjugates could provide increased enzyme binding sites, which may result in higher enzyme loading. Thus, the proposed uricase/ZnS QDs/l-cys biosensor exhibited higher amperometric response compared to the one without QDs (uricase/l-cys biosensor). In addition, there was little AA interference. It showed a linear dependence on the uric acid concentration ranging from 5.0x10(-6) to 2.0x10(-3)molL(-1) with a detection limit of 2.0x10(-6)molL(-1) at 3sigma.

Biosensor Based on TTF@ SiO2 Nanoparticles as Electron Transfer Mediator for the Determination of Glucose1

Tetrathiafulvalene(TTF) was doped in an SiO 2 network and the resulting nanocomposite was used as a mediator for the selective detection of glucose. The uniform TTF-doped silica(TTF@ SiO 2 ) nanoparticles were prepared by the water-in-oil(W/O) microemulsion method, and were characterized by transmission electron microscopy(TEM). The core-shell structure TTF@ SiO 2 could prevent TTF from leaching out into an aqueous solution. Combined with chitosan(CHIT), which serves as a scaffold for glucose oxidase and nanocomposite immobilization, the GCE/TTF@ SiO 2 -CHIT-GOx biosensor was developed. Under optimal conditions, the biosensors exhibit a linear range of 1.0 × 10 −5 –5 × 10 −3 mol/L with a detection limit down to 5.0 μmol/L( S/N = 3). The excellent selectivity, sensitivity, and stability of the glucose biosensor show its potential for practical applications.

Black coral as a new environmental recorder: The lead profiles in coral skeletons over the past century

Lead (Pb) is a typical heavy metal pollutant in the environment, and most Pb contamination comes from human activities. In the present work, the Pb contents of two black coral specimens (Cirrhipathes spp.) collected from the northern South China Sea were measured by synchrotron radiation micro X-ray fluorescence (SR μ-XRF) analysis with 2.5 μm resolution. The results showed that sample SY-1 from the Sanya Bay (near the continent) exhibited higher Pb levels and greater fluctuations than sample XS-1 from the Xisha Islands (off the continent), reflecting the influence of terrestrial input and atmospheric deposition in coastal surface seawater. The present work also demonstrated that the Pb profile in black coral nearshore was highly influenced by human activities, mainly by war and economic development. Thus, black coral may serve as a new potential environmental Pb recorder with SR μ-XRF analytical technology.