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|Title: ||Biological applications of functional micro-/nano-structures|
|Other Titles: ||Wei na mi jie gou de gou jian ji qi sheng wu xue ying yong|
|Authors: ||Zhang, Wenjun (張文軍)|
|Department: ||Department of Physics and Materials Science|
|Degree: ||Doctor of Philosophy|
|Issue Date: ||2010|
|Publisher: ||City University of Hong Kong|
|Notes: ||CityU Call Number: TP248.25.N35 Z45 2010|
xix, 169 leaves : ill. 30 cm.
Thesis (Ph.D.)--City University of Hong Kong, 2010.
Includes bibliographical references.
|Abstract: ||With shrinking dimensions, materials possess very different properties compared to
their bulk counterparts. This provides the incentives to scientific researchers to
investigate their properties and develop novel applications. Owing to the proven
excellent performance of micro/nano- structures such as controllable release of ions
from buried nano-scaled thin layers, cell response to micro-scaled morphological
changes of substrates, enhanced sensitivity rendered by electrodes with sizes less than
10 micrometers, and dramatically increased electromagnetic field from local surface
plasmon resonance of nanostructures, there is plenty of room for researches to develop
such micro/nano- structures, especially in the challenging biological field.
The objectives of the research work described in this thesis are as follows: (1) to modify
the surface of transparent materials or to fabricate two dimensional micro-structures on
transparent materials to observe cell behaviors and to attempt to figure out the key
factors that control cell behaviors, (2) to produce micro-scaled and even nano-scaled
electrodes for the high spatial-temporal detection of chemical reactions and biological
phenomena, (3) to synthesize nano-structured materials using chemical routes for
surface enhanced Raman spectroscopy (SERS) detection, and (4) to prepare
nanostructures using the template approach for large SERS substrates. The goal is
integration of micro-devices for biological applications.
This thesis is composed of five main parts. Firstly, fabrication of buried nano-scaled
layers and micro-structures on transparent substrates for cell manipulation is described.
The quartz is treated by plasma immersion ion implantation (PIII) to regulate the cell
pattern and polydimethylsiloxane (PDMS) is modified by soft lithography to control
cell behaviors. The results suggest that ions released from the buried layer can affect
the attached neural cells and even control their behavior. The quartz modified by PIII
exhibits stable performance that may be used in lab-on-a-chip devices. The versatility
of modified PDMS also renders itself a promising candidate in integrated biological
Secondly, a method to fabricate electrodes on the ultramicro- and nano- scales routinely
is discussed. The as-prepared carbon fiber electordes are utilized to monitor the
secreting behavior of neurons. The intrinsic properties of micro- and nano- electrodes
make high spatial-temporal resolution detection a reality. The Kiss and Run (K&R)
mechanism is shown to be the preferred mode of neural exocytosis.
Thirdly, a wet chemical approach to prepare nanostructures on SERS substrate is
described. The convenient self-selective electroless plating technique is demonstrated
to yield silver dendritic nanostructures based on the diffusion-limited aggregation
process. Such nano-scaled fractals have great potential as excellent SERS substrates for
Fourthly, two nanostructures fabricated by the anodic aluminum oxide (AAO) template
are described. The silver nanorods are formed in the AAO holes by drying and
decomposition of absorbed silver nitrate at high temperature. The silver nanorod arrays are used to detect fluorescent molecules at trace levels. The silver nanocaps on the
hexagonal structures of the AAO are prepared by direct current magnetron sputtering.
The nanocap arrays have large potential with regard to bio-molecule detection. The
nano-structures produced by the template approach are normally clean and uniform and
cover a large area, thereby making them high performance SERS substrates.
Finally, possible future work based on this thesis is proposed. One direction is to
integrate the modified substrates and as-prepared electrodes into a lab-on-a-chip system.
This will facilitate researchers to probe cell behaviors and mechanisms. Another
possibility is to develop optimized SERS substrates for quantitative analysis of
biological molecules. The latter will broaden the applications of Raman spectroscopy.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b3947666|
|Appears in Collections:||AP - Doctor of Philosophy |
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