Label-Free, Real-Time Phospholipase-A Isoform Assay.

Area of Science:

• Biotechnology and Biosensing
• Enzyme Activity Monitoring
• Medical Diagnostics

Background:

• Phospholipase A (PLA) enzymes are crucial in biological processes and disease states like pancreatitis.
• Existing PLA sensors face limitations including assay preparation time, reliance on fluorescent labels, and strict pH requirements.
• Distinguishing between PLA1 and PLA2 isoforms is important for accurate analysis.

Purpose of the Study:

• To develop a rapid, real-time impedance sensor array for detecting PLA activity.
• To enable selective detection and differentiation of phospholipase A1 (PLA1) and phospholipase A2 (PLA2) isoforms.
• To overcome limitations of current PLA sensing technologies.

Main Methods:

• Utilized a tethered bilayer lipid membrane (tBLM) impedance sensor array.
• Employed swept-frequency electrical impedance spectroscopy for real-time measurements.
• Tested tBLMs composed of ether, ester, or ether-ester phospholipids to differentiate isoforms.

Main Results:

• The tBLM sensor array successfully detected and differentiated PLA1 and PLA2 isoforms.
• Identified calcium-dependent PLA2 activity in bullet ant venom (1 μg/mL) with specificity confirmed by mass spectrometry.
• Detected PLA1 activity as low as 0.06 U/mL, demonstrating high sensitivity across various buffers.

Conclusions:

• The tBLM impedance sensor array provides rapid, reliable, and selective detection of PLA activity.
• This sensor technology offers a significant advancement over existing methods for enzyme analysis.
• Potential applications include venom studies, lipase bioreactors, and point-of-care diagnostic devices.