Selective layer-free blood serum ionogram based on ion-specific interactions with a nanotransistor

Area of Science:

• Nanotechnology
• Surface Chemistry
• Biomedical Diagnostics

Background:

• Ion-specific effects of electrolytes present challenges in chemistry and biology.
• Limited understanding of ion-specific surface interactions hinders development of (bio-)chemical sensors.
• Need for advanced materials for sensitive and selective ion detection.

Purpose of the Study:

• To investigate ion-specific surface interactions using scaled-down silicon nanotransistors.
• To develop a sensor platform highly sensitive to cations and inert to pH.
• To enable selective measurement of target ion concentrations in complex solutions.

Main Methods:

• Fabrication of silicon nanotransistor sensors with dimensions of approximately 25 nm.
• Utilizing molecular dynamics simulations to understand ion-surface interactions and overscreening effects.
• Characterizing sensor response to various cations and multi-ion solutions.

Main Results:

• Demonstrated unprecedented sensitivity to Na+ and divalent ions due to an overscreening effect.
• Showed that surface potential in multi-ion solutions is predictable by summing individual cation electrochemical potentials.
• Achieved selective ion concentration measurements without needing selective organic layers.

Conclusions:

• Scaled silicon nanotransistors offer a unique platform for understanding and exploiting ion-specific surface interactions.
• The developed sensor technology enables selective cation detection, crucial for diagnostic applications.
• Successfully constructed a blood serum ionogram (Na+, K+, Ca2+, Mg2+), advancing towards versatile diagnostic tools.