research associate professor
Ph.D., Huazhong University of Science and Technology, China
Fields of Interest
Nano-biotechnology with nanomaterials, especially carbon nanotubes and metallic nanoparticles, incorporated devicing.
Nanotechnology emerges from the physical, chemical, biological, and engineering sciences, where novel techniques are being developed to probe and manipulate single atoms and molecules. The studies have impacted manufacturing processes of a wide range of materials and devices, resulting in substantial improvements of existing technology as well as entirely new technological innovations. While significant progress has been made in material science, it is apparent that nanoscience and nanotechnology-based approaches are poised to revolutionize research in biology and medicine. Nanotechnology can be used to design diagnostic systems that not only define early stage changes or progression to a disease state, but also allow the identification of unique biological molecules, chemicals and structures not addressable by current assays. In addition, nanotechnology and nanoscience offer new opportunities in the treatment and management of diseases and traumatic injuries. Nanoscale multifunctional materials also allow targeted delivery of molecular therapeutics with enhanced efficacy.
My research can be identified in several major areas:
1) Nanomaterial facilitated biomolecule delivery. The structural size in the range less than 100 nm gives the nanomaterials advantages to transport across cell membranes. It holds promises in the development of molecular vehicles. The carbon nanotube, nanowire, and dendrimer are used for this purpose. Nanospearing, for example, is developed to conduct highly efficient transfection in difficult-to-transfect cells. In this technique, we employed the magnetic responsive carbon nanotube to carry surface condensed biomolecules across cell membrane with the magnetic force. In addition, nano- electroporations are also in developing by utilizing the conductive one-dimensional nanomaterials such as carbon nanotube and nanowire to enhance electrical fields. Such methods are speculated to revolutionize the techniques in drug delivery and vaccination.
2) Nano-biosensor. Nanomaterials can offer the molecular level interaction with protein, DNA and RNAs etc, thereby open avenues to investigate the deviations of molecules due to the bio- processes of interest. In our mediator-free electrochemical detection, nanotube, nanoparticle and redox enzymes are assembled together to carry out highly sensitive detection based on the direct electron transfer between the redox enzymes and the electrode. With the advanced nanofabrication technique, we can identically produce nano- coaxial arrays that can offer extreme sensitive biosensing at the single molecule level based on impedance spectroscopy and time domain spectroscopy. Such a biosensor holds promise for early stage diagnosis, bio-warfare detection, environmental monitoring, narcotic and explosive detections.
3) Nano-biointerface. It is been revealed that nanoscale structures are preferential to the growth of adherent cells in culture. Also, the nanomaterial interface with biomolecule modifications demonstrated extraordinary advantages to promote cell proliferation or differentiation. In a collaborative research, carbon nanotube was decorated with specific biofunctional proteins and deposit as a monolayer on the culture surface to manipulate the stem cell differentiation.
4) Biocompatibility of nanomaterials. Nanomaterials have raised significant concerns over the public health and environmental problems. Carbon nanotube, for example, was found to produce carcinogenic effected in animal pulmonary tissues. In vitro study also revealed cytotoxicity due to the oxidant stress correlated to the carbon nanotubes. Our research demonstrated that, if properly functionalized and decorated with other groups and molecules, carbon nanotube can be biocompatible to mammalian humoral immune cells. This study will help to eliminate one of the primary obstacles for the biomedical applications of nanomaterials.
The techniques required to carry out the multidisciplinary studies include:
• Chemical vapor deposition, plasma enhanced chemical vapor deposition, magnetron sputtering deposition, electron beam evaporation, thermal vapor deposition, polystyrene sphere masking, photolithography, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, fluorescence microscopy, UV spectrometry, Raman spectrometry, organic synthesis, electrochemistry (voltammetry, amperometry, electrochemical impedance spectrometry), and broadband impedance spectrometry.
• Cell culture, DNA/RNA purification, protein purification, RT-PCR, real time PCR, western blot, agar gel electrophoresis, SDS-PAGE electrophoresis, flow cytometry, lipofectamine transfection, electroporation, cationic polymer based transfection, plasmid amplification, immunofluorescence staining, and bioconjugation chemistry.
Yu, Y., Cimeno, A., Lan, Y.C., Rybczynski, J., Wang, D.Z., Paudel, T., Ren, Z.F, Wagner, D.J., Qiu, M. Q., Chiles, T.C., and Cai, D. 2009. Assembly of multi-functional nanocomponents on periodic nanotube array for biosensors. Micro & Nano Letters 4: 27–33.
Cai, D., Blair, D., Dufort, F.J., Gumina, M.R., Huang, Z., Hong, G., Wagner, D., Canahan, D., Kempa, K., Ren, Z.F., and Chiles, T. C. 2008. Interaction between carbon nanotubes and mammalian cells: characterization by flow cytometry and application. Nanotechnology 19: 345102–12.
Cai, D., Kempa, K., Ren, Z., Carnahan, D., and Chiles, T.C. 2007. Nanospearing — the biomolecule delivery and its biocompatibility. In Nanomaterials for Application in medicine and Biology (Eds.: Giersig, M. and Khomutov, G.B.), Springer, Dordrecht, the Netherlands.
Cai, D., Yu, Y., Lan, Y., Xiong, G., Paudel, T., Ren, Z.F, Wagner, D.J., and Chiles, T.C. 2007. Glucose sensors made of novel carbon nanotube-gold nanoparticle composites. BioFactors 30: 271–277.
Cai, D., Doughty, C. A., Potocky, T. B., Dufort, F.J., Huang, Z., Blair, D., Kempa, K., Ren, Z. F., and Chiles, T.C. 2007. Carbon nanotube-mediated delivery of nucleic acids does not result in non-specific activation of B lymphocytes. Nanotechnology 18: 365101.
Rybczynski, J., Kempa, K., Herczynski, A., Wang, Y., Naughton, M. J., Ren, Z. F., Huang, Z. P., Cai, D., and Giersig, M. 2007. Subwavelength waveguide for visible light. Applied Physics Letters 90: 021104.
Cai, D., Mataraza, J. M., Qin, Z.-H., Huang, Z., Huang, J., Chiles, T.C., Carnahan, D., Kempa, K., and Ren, Z. 2005. Highly efficient molecular delivery into mammalian cells using carbon nanotube spearing. Nature Methods 6: 449–454.