Label-Free Protein Analysis Using Liquid Chromatography with Gravimetric Detection

Area of Science:

• Analytical Bioscience
• Biophysics
• Analytical Chemistry

Background:

• Label-free detection of native proteins in solution is crucial for bioscience.
• Existing methods often require labels or lack analyte selectivity.
• Mechanical resonators offer label-free sensitivity but struggle with selectivity in liquid phases.

Purpose of the Study:

• To develop a label-free analytical strategy for protein mixtures.
• To overcome selectivity limitations in dry mass sensing approaches.
• To enable quantitative protein analysis under physiological conditions.

Main Methods:

• Coupling liquid chromatography with a quartz crystal microbalance (QCM) platform.
• Utilizing a microfluidic spray dryer for sample preparation.
• Employing size exclusion chromatography for protein separation, desalting, and spray-drying onto QCM.

Main Results:

• Achieved simultaneous protein mass detection and sample fractionation.
• Demonstrated a limit of detection down to 100 μg/mL.
• Established a continuous flow interface between chromatography and spray device via a flow splitter.

Conclusions:

• The developed approach enables quantitative, label-free analysis of protein mixtures.
• This method overcomes selectivity issues by integrating chromatography with QCM.
• Offers potential for detecting protein species under native physiological conditions.