Recently, two research papers from Prof. Long Yi-Tao’s group on “Single Molecule Detection of Critical Diseases” have been published on Scientific Reports, an affiliated journal of NPG (Nature Publishing Group). These two works mainly reported on Co-enzyme Q functionalized quantum dots as fluorescent sensor for early diagnosis of Parkinson’s disease (Scientific Reports 2013, 3, doi:10.1038/srep01537) and Single molecule monitoring Host-Guest supramolecular behavior by biological nanopores, respectively (Scientific Reports 2013, 3, doi:10.1038/srep01662).

    Based on previous research of bio-mimic membrane interface system (Nature Protocols 2013, 8, 439-450), Dr. Ma Wei and Dr. Qin Li-Xia reported a biosensor of complex I using ubiquinone-terminated disulphides with different alkyl spacers as surface-capping ligands to functionalise CdSe/ZnS QDs. The enhancement or quenching of the QD bioconjugates fluorescence changes as a function of the redox state of QnNS, which could be modulated by adding NADH. This performance simulates an electron-transfer system part of the mitochondrial respiratory chain, providing an in vitro and intracellular complex I sensor. This novel QnNS-QDs system has a potential in early stage diagnosis and progression monitoring of Parkinson’s disease by tracing complex I levels in human neuroblastoma SH-SY5Y cells, since epidemiological studies suggest that Parkinson’s patients have the impaired activity of complex I in the electron-transfer chain of mitochondria.

    Meanwhile, in order to achieve single molecule detection of supramolecular interaction and sensing mechanism, a multi-stimuli responsive nanopore system based on photo-modulable host-guest system was established under the collaboration between Prof. Tian He’s group and Prof. Long Yi-Tao’s group. The open-close states of the ion channels in a living system are regulated by multiple stimuli such as ligand, pH, potential and light. Functionalizing natural channels by using synthetic chemistry would provide biological nanopores with novel properties and applications. In this research work, para-sulfonato-calix[4]arene-based host-guest supramolecular system was utilized to develop artificial gating mechanisms aiming at regulating wild-type a-HL commanded by both ligand and light stimuli. Using the gating property of a-hemolysin, the host-guest interactions between para-sulfonato-calix[4]arene and photo-responsive azobenzene derivatives was studied at the single-molecule level. Subsequently, the real-time study of light-induced molecular shuttle based on para-sulfonato-calix[4]arene and azobenzene derivatives at the single-molecule level was also carried out. This hybrid system provides a more efficient method to develop a general tool to analyze the individual motions of supramolecular systems by using commercially available a-HL nanopores. This project was successfully accomplished by Dr. Zhang Junji and Ph. D student Ying Yi-Lun under the supervision of Prof. Tian He and Prof. Long Yi-Tao, respectively. Prof. Itamar Willner of the Hebrew University of Jerusalem (Israel) also contributed to this project.

    These two research projects are supported by the National Base Research 973 Program (Basic Research on Detection of Tumor-specific Serum Marker by Molecular Sensors) and the National Science Fund for Distinguished Young Scholars of China.

    Related Linkers:

    http://www.nature.com/srep/2013/130416/srep01662/full/srep01662.html

    http://www.nature.com/srep/2013/130325/srep01537/full/srep01537.html