Continuous detection of extracellular ATP on living cells by using atomic force microscopy

Area of Science:

• Biophysics
• Cell Biology
• Nanotechnology

Background:

• Atomic force microscopy (AFM) is crucial for studying living cell surfaces under physiological conditions.
• AFM resolution is often limited by cell softness and tip-sample interactions.
• Detecting specific biomolecules on cell surfaces remains a challenge.

Purpose of the Study:

• To develop and validate a novel AFM-based method for detecting adenosine triphosphate (ATP) on living cells.
• To explore the use of myosin-functionalized cantilevers as biosensors for ATP.
• To assess the feasibility of simultaneous topographical and biochemical analysis of cell surfaces.

Main Methods:

• Utilized atomic force microscopy (AFM) with myosin-functionalized scanning tips (cantilevers).
• Scanned the surface of CFTR+ cells (S9 cell line) to detect basal ATP concentrations.
• Compared results using enzymatically active tips with noncoated and heat-inactivated enzyme-coated tips.

Main Results:

• Atomic force microscopy successfully detected basal adenosine triphosphate (ATP) concentrations on the surface of living CFTR+ cells.
• ATP-dependent signals were absent when using noncoated or inactivated enzyme-coated tips, confirming specificity.
• The study demonstrated the potential for functionalized AFM tips to act as biosensors.

Conclusions:

• Myosin-functionalized AFM cantilevers can serve as effective biosensors for detecting ATP on living cell surfaces.
• This approach advances the development of AFM-based biosensors for simultaneous topographical and biochemical analysis.
• Future applications include real-time monitoring of biologically important compounds in the cellular microenvironment.