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Effects of electrode surface modification with chlorotoxin on patterning single glioma cells
Fareid Asphahani1, Xiaohao Zheng, Omid Veiseh
1Department of Materials Science & Engineering, University of Washington, Seattle, WA 98195, USA.
Abstract:
A microchip patterned with arrays of single cancer cells can be an effective platform for the study of tumor biology, medical diagnostics, and drug screening. However, patterning and retaining viable single cancer cells on defined sites of the microarray can be challenging. In this study we used a tumor cell-specific peptide, chlorotoxin (CTX), to mediate glioma cell adhesion on arrays of gold microelectrodes and investigated the effects of three surface modification schemes for conjugation of CTX to the microelectrodes on single cell patterning, which include physical adsorption, covalent bonding mediated by N-hydroxysuccinimide (NHS), and covalent bonding via crosslinking succinimidyl iodoacetate and Traut's (SIA-Traut) reagents. The CTX immobilization to microelectrodes was confirmed by high-resolution X-ray photoelectron spectroscopy. Physically adsorbed CTX showed better support for cell adhesion and is more effective in confining adhered cells on the electrodes than covalently-bound CTX. Furthermore, cell adhesion and spreading on microelectrodes were quantified in real-time by impedance measurements, which revealed an impedance signal from physically adsorbed CTX electrodes four times greater than the signal from covalently-bound CTX electrodes.
Insights
This study demonstrates that physically adsorbed chlorotoxin (CTX) on microelectrodes enhances single cancer cell adhesion and patterning on microarrays. This method is more effective for tumor biology research and diagnostics than covalent CTX binding.
Area of Science:
- Biomedical Engineering
- Cancer Research
- Materials Science
Background:
- Microarrays patterned with single cancer cells are valuable for tumor biology, diagnostics, and drug screening.
- Challenges exist in patterning and maintaining viable single cancer cells on microarrays.
Purpose of the Study:
- To investigate surface modification schemes for conjugating chlorotoxin (CTX) to gold microelectrodes for glioma cell adhesion.
- To compare physical adsorption versus covalent bonding methods for CTX immobilization.
- To assess the impact of these methods on single cell patterning and adhesion.
Main Methods:
- Utilized chlorotoxin (CTX), a tumor cell-specific peptide, to mediate glioma cell adhesion.
- Investigated three CTX conjugation methods: physical adsorption, NHS-mediated covalent bonding, and SIA-Traut mediated covalent bonding.
- Confirmed CTX immobilization using X-ray photoelectron spectroscopy.
- Quantified cell adhesion and spreading in real-time using impedance measurements.
Main Results:
- Physically adsorbed CTX demonstrated superior support for cell adhesion and more effective confinement of adhered cells compared to covalently-bound CTX.
- Impedance measurements revealed a four-fold greater signal from physically adsorbed CTX electrodes, indicating enhanced cell adhesion and spreading.
- CTX immobilization was successfully confirmed on microelectrodes.
Conclusions:
- Physical adsorption is a more effective strategy than covalent bonding for immobilizing CTX on microelectrodes to achieve robust single cancer cell patterning.
- This approach offers a promising platform for advancing cancer research, diagnostics, and drug screening applications.
