Shiping Song obtained his PhD in Inorganic Chemistry at Shanghai Institute of Applied Physics, Chinese Academy of Sciences (CAS), in 2004. He currently holds position as Professor in the Division of Physical Biology at Shanghai Advanced Research Institute, CAS and is a Humboldt Scholar in the Institute of Inorganic Chemistry at the University of Cologne. His expertise is in the field of nanomaterials, microscale structures and biological analysis, with a special focus on nano-based biosensors and biochips. He has co-authored more than 140 articles and chapters. He is an ad hoc reviewer for more than 20 international journals, as well as for several granting agencies.
Statement of the Problem: Biosensors and biochips have greatly promoted the development of the fields of genomics, proteomics, and clinical assays because of their remarkably rapid and high-throughput assay capability. Immobilization strategies for biomolecules on a solid support surface play a crucial role in the fabrication of high-performance biosensors and biochips. Methodology: Rationally designed DNA tetrahedra carrying three thiol/amino groups and one single-stranded DNA extension were synthesized by the selfassembly of four oligonucleotides, followed by high-performance liquid chromatography purification. We fabricated DNA tetrahedron-based biosensing chips by covalently coupling the DNA tetrahedron onto gold/silicon/carbon substrates. After their biorecognition capability was evaluated, DNA tetrahedron biosensing interfaces were utilized for the analysis of different types of bioactive molecules. The gap hybridization strategy, the sandwich configuration, and the engineering aptamer strategy were employed for the assay of miRNA biomarkers, protein cancer biomarkers, and small molecules, respectively. Findings: The arrays showed good capability to anchor capture biomolecules for improving biorecognition. Addressable and high-throughput analysis with improved sensitivity and specificity had been achieved. More importantly, we demonstrated that the biosensing platform worked well with clinical serum samples and showed good relativity with conventional bioassays. Conclusion & Significance: We have developed a novel approach for the fabrication of DNA tetrahedron-based biosensing chips and a universal DNA tetrahedron-based biosensing platform for the detection of different types of bioactive molecules. The biosensing platform shows great potential for practical clinical diagnosis.
“Ray” Duanghathaipornsuk received the BS degree in industrial chemistry from Chiang Mai University, Thailand. Currently, he is a Chemical Engineering PhD candidate in the University of Toledo, has been working on free radical sensor development for three years and has played a critical role in developing the sensor for hydroxyl radical detection. He is interested in the research area of using inorganic nanocatalyst for developing a sensor array.
Free radicals are recognized as essential molecules for upholding the function of normal cells. The immune systems such as eliminating bacteria and inactivating virus are the example for the crucial role of free radicals in cells. Even though free radicals have benefits on human cells, the optimum production is the key to maintain their advantages. High concentrations of free radicals in a human body may cause cancer, Alzheimer’s disease or Parkinson’s disease. Among several free radical species, hydroxyl radicals (•OH) are the highest reactive and the most dangerous free radical. •OH is also one of the biomarkers that are identified during an initial stage of severe disease development. Thus, to diagnose the developing of those diseases, a very sensitive analytical sensor is needed for •OH detection at low concentrations. The integration of an electrochemical technique with a sensing system is regarded as a promising method for •OH detection due to a rapid and direct measurement without the pretreatment of samples. Thus, in this study, a glassy carbon electrode (GCE) was modified with Vulcan carbon/cerium oxide nanoparticles (CeO2 NPs) composite to be used as a sensing device for •OH. The composite of Vulcan carbon/CeO2 NPs was synthesized through the controlled surface reaction. X-ray powder diffraction (XRD) helped to confirm the composition of the Vulcan carbon/CeO2 NPs composite. Transmission electron microscopy (TEM) was used to determine the average size of CeO2 NPs in the composite. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were implemented to characterize the interaction of the composite sensor with •OH. The GCE modified with Vulcan carbon/CeO2 NPs composite was used to detect •OH in Fenton reaction compared to bare GCE. As expected, there is no oxidation current response occurring from the bare GCE. The modified GCE, however, showed a significant increase in oxidation current response. Moreover, it demonstrated the linear relationship between oxidation current response and •OH concentration in the range of 0.1 mM to 10 mM. From the preliminary result, it is suggested that the Vulcan carbon/CeO2 NPs composite can be used to modify the sensor for •OH detection.