The long-range effect induced by untying hydrogen bonds for single cell test using SECM

• The enhanced positive feedback current of SECM is observed at a large tip-substrate separation in the case of a 3-MPA SAM.
• The long-range effect is resulting from concentration increment of redox species by untying the hydrogen bonds beforehand formed between the tip redox species and the 3-MPA SAM.
• The long-range effect is applied to the single cell test using SECM which is beneficial for cell tests without affecting the natural metabolic pathway and cell morphology.

The enhanced positive feedback current of scanning electrochemical microscopy (SECM) is observed at a large separation between the tip and the substrate surface in the case of a 3-mercaptopropionic acid (3-MPA) self-assembled monolayer (SAM). The effect that induces the large separation (named the long-range effect) is confirmed by SECM and quantitatively studied by electrochemical quartz crystal microbalance (EQCM). A key finding is that the long-range effect results from untying hydrogen bonds beforehand formed between the hydroxyl group of tip redox species and the carboxyl group of 3-MPA SAM. It is found that the long-range effect is increased with the packing density of the 3-MPA SAM. On the basis of these findings, the long-range effect is applied to the nondestructive test of living cells using SECM.

Figure optionsDownload as PowerPoint slide