20
solution. For example, an electric eld of 25 V/µm is required to overcome the inu-
ence of PDMS insulation layer.
4. Photolithography mold method, a nano-conductive material (nano-carbon powder or
nano-silver powder) is mixed with PDMS, and the mixture is plastered to a photoli-
thography mold, and then use blade to scrape and form a pattern, which is embedded
into the PDMS microchannel [145]. Lewpiriyawong et al. prepared a thick-electrode
chip using a mixture of nano-silver powder and PDMS (AgPDMS) to achieve separa-
tion of particles and cells [146]. Based on the same processing technology, Marchalot
et al. used a mixture of nano-conductive carbon powder and PDMS (C-PDMS) to
make a thick-electrode chip to achieve cell enrichment [147]. is PDMS conductive
mixture retains the properties of PDMS, which can be easily bonded to the substrate.
e thick electrodes have high conductivity, ductility and repeatability.
1.4 RESEARCH PURPOSES AND SIGNIFICANCES
Biomanipulation based on DEP technology is currently a research hotspot in academia. In order
to overcome the limitations of 2D electrodes, the thick-electrode structures are adopted to design
single-cell operation chip, especially to solve the problem of single-cell 3D rotation. First, by con-
structing a multi-electrode structure with thick electrodes to realize single-cell 3D electro-rotation,
electrical parameter measurement and morphology imaging. is work can demonstrate the value
of thick-electrode DEP multi-electrode structure in the eld of single-cell manipulation. On this
basis, the thick-electrode DEP multi-electrode structure is expanded by opto-electronic integra-
tion, and dual optical bers are embedded in the thick electrodes, which enable the chip to rotate
and stretch single cells, achieving multi-parameter measurement of mechanical and electrical prop-
erties of single cells, extends the application of thick-electrode DEP in biological manipulation
and analysis.
1.5 MAIN CONTENT OF THE BOOK
Chapter 1: Introduction. e background and signicance of the topic. First, the background and
current situation of microuidic development are briey summarized. e materials and processing
methods of the microuidic chip were analyzed, and the typical biological manipulation mecha-
nisms are compared according to the technical means.
e research progress of single-cell manipulation by DEP is introduced. en the research
status of electrode processing in DEP technology is analyzed, and the method basis is provided
for the design of chip structure. Finally, the purpose and signicance of this research are proposed
according to the requirements of biological applications.