Xiaonan Wang,Meiwen Wang,Yuanyuan Zhang,Xiaocao Miao,Yuanyuan Huang,Juan Zhang,Lizhou Sun
A new strategy to fabricate electrochemical biosensor is reported based on the linkage of enzyme substrate , thereby an electrochemical method to detect aldolase activity is established using pectin-thionine complex (PTC) as recognization element and signal probe . The linkage effect of fructose-1,6-bisphosphate (FBP), the substrate of aldolase, can be achieved via its strong binding to magnetic nanoparticles (MNPs)/aminophenylboronic acid (APBA) and the formation of phosphoramidate bond derived from its reaction with p -phenylenediamine (PDA) on the surface of electrode. Aldolase can reversibly catalyze the substrates into the products which have no binding capacity with MNPs/APBA, resulting in the exposure of the corresponding binding sites and its subsequent recognization on signal probe. Meanwhile, signal amplification can be accomplished by using the firstly prepared PTC which can bind with MNPs/APBA, and accuracy can be strengthened through magnetic separation. With good precision and accuracy, the established sensor may be extended to other proteins with reversible catalyzed ability.
Qian Liu,Tingyan Shi,Yong Cheng,Zuorui Wen,Caifeng Ding,Yaqi Li,Kun Wang
Developing effective analytical method for sulfadimethoxine (SDM) detection is highly desirable and vitally crucial for protecting environment safety and human health. Herein, a highly selective and sensitive photoelectrochemical (PEC) aptasensor for accurate detection of SDM was proposed, which employed zinc phthalocyanine/graphitic carbon nitride (ZnPc/CN) nanocomposite as photosensitive material. The ZnPc/CN nanocomposite was constructed by modification of CN nanosheet with visible/near-infrared light responsive photosensitizer ZnPc. The introduction of ZnPc into CN exhibited amplified PEC response, which was 5.7 and 18.3 times than pure ZnPc and CN, attributed to the enhanced light harvesting ability and improved photoelectric conversion efficiency of such nanocomposite. By using ZnPc/CN and sulfadimethoxine (SDM) aptamer as PEC response material and specific probe, a PEC aptasensor was established for SDM detection. The aptamer was connected to the surface of chitosan/ZnPc/CN/ITO through the formation of phosphoramidate bonds between the amino group of the chitosan and phosphate group of the aptamer at 5′ end. The fabricated aptasensor displayed good detection linearity of 0.1 ~ 300 nM and low detection limit of 0.03 nM (S/N = 3) under optimized conditions, and the potential applicability of the PEC aptasensor was confirmed by detecting SDM in milk powder samples.
危险品化学品经营许可证（带存储）