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Research

Summary
The motivation of the Biomedical Science and Nanotechnology laboratory directed by Dr. Mihri Ozkan is the development of bio-assisted assembly methods for future nanoelectronics, synthesis and application of novel hybrid, multi-functional and complex nanoscale systems for fabrication of better displays, development of solar cells, and development of cancer therapeutics. Our group members come from highly interdisciplinary backgrounds including electrical engineering, chemical engineering, chemistry, biochemistry and cellular biology. This multi-disciplinary environment offers both graduate and undergraduate students training in multi-disciplinary fields including biology and engineering.

List of Current  Research Activities

Bionanoelectronics

In order to produce low power, high-speed complex electronics, we use self-assembly to built functional nanostructures. We synthesize and test assemblies of carbon nanotube, nanowire and nanocrystals using DNA, PNA or peptides as “super glue”. For the first time, we have demonstrated:

•        Negative resistance characteristics of nanotube-DNA-nanotube junctions (X. Wang et al. Small 2006, K. Singh et al. Carbon 2006) .

•        Bi-stable behavior of CPMV icosahedral plant virus-nanocrystal memories and assemblies of carbon nanotubes (N. Portney et al Langmuir 2005, N.Portney et al. ACS Nano 2008, N. Portney et al APL 2007).

•        Heterojunctions of nanocrystals and nanotubes ( S. Ravindran et al. Nanoletters 2003, S. Chaudhary et al. Nanoletters 2004, B.Pan J. Phys. Chem. C 2008)

•        Integration of nanowires on Si-CMOS ( E. Akin et al, Techcon 2007)

•        Errorless assembly with engineered DNA sequences (J. Huan et al. NIST 2007)

•        Encode digital information in DNA based on partial restriction digest (N.Portney et al Langmuir, 2008)

•        Numerical addition and subtraction using DNA-SiCMOS as a hybrid computer

Our work on DNA-nanoarchitectonics  is featured on the cover of the National Academy of Engineering The Bridge (2009) and our related article is published in this journal.

Below is a gallery of samples of our related work.

 

Hybrid Organic Inorganic Solar Technology

To produce affordable and efficient solar energy harvesting devices we have been focusing on the architecture, materials and interface aspects of hybrid photovoltaics. We have demonstrated:

•        Alternative better performing hole collection contacts using single walled carbon nanotubes in P3HT-PCBM photovoltaics ( S. Chaudhary et al Nano Letters 2007)

•        Trilayer architecture for the active layer in LEDs ( S. Chaudhary et al APL 2004)

•        Effect of processing conditions on the performance of P3HT-PCBM photovoltaics (H. Lu et al JNO 2007)

•        Enhanced charge injection and collection at the contacts using nanoparticles of ITO (O. Yilmaz et al Nanotechnology 2006)

•        Enhanced charge transport between PbS nanocrystal and P3HT after surface modification of PbS nanocrystals with pyridine (H. Lu et al and L. Wang et al)

Below is a gallery of samples of our related work.

Bionanotechnology and Imaging

Our achievements in this category includes:

•        Image enhancement nanoparticles such as iron oxide nanocrystals are used with different surface functional groups. Cellular uptake are studied with our model system human healthy and tumor breast  cell lines ( Y. Zhang et al Biomedical Microdevices 2008, Y. Zhang et al Biotechnology Progress 2009).

•        Virus hybrids of iron oxide nanocrystals are demonstrated for improved magnetic imaging in nano-oncology applications ( A. Martinez et al Advanced Materials 2008, N.Portney et al Anal. Bioanal.Chem, 2006, M.Ozkan Drug Discovery today 2004).

•        We built a custom hybrid near-field-scanning-optical system with confocal fluorescent imaging capacity. Human breast tissue samples are imaged and their nucleus are labeled. Our work aims to early detection of tumor cells at single cell resolution. (Y.Zhang et al MRS Proceedings 2008)

•        Together with our collaborators in UCSD microfluidic chips are integrated with optical manipulation capability for high throughput screening of cells. ( M.Ozkan et al Optics Letters 2000, M.Ozkan et al IEEE-EMB 2001, M.Ozkan et al Biomedical Microdevices 2003, A. Birkbeck Biomedical Microdevices 2003, M.Ozkan et al Langmuir 2003, R. Flynn et al Biosensors and Bioelectronics 2006, B. Shao et al Optics Letters 2006, B. Shao Biomedical Microdevices 2007)

•        Neuron based micro-array sensors are developed for detection of potential chemical environmental changes (i.e. toxins) (S. Prasad et al Biosensors and Bioelectronics 2006, S. Prasad et al Electrophoresis 2004, S. Prasad et al Biosensors and Bioelectronics 2004, S. Prasad et al J. of Neuroscience Methods 2004, M.Yang et al Sensors Letters 2004)

Below is a gallery of samples of our related work.