Integrating Particle Motion Tracking into Thermal Gel Electrophoresis for Label-Free Sugar Sensing

Area of Science:

• Bioanalytical Chemistry
• Analytical Separations
• Microfluidics

Background:

• Bioanalytical sensors offer high sensitivity but limited multiplexing.
• Analytical separations provide multiplexing but often require analyte labeling for sensitivity.
• A need exists for sensitive, label-free quantification of unlabeled analytes in complex matrices.

Purpose of the Study:

• To develop a separation-based sensor for sensitive, label-free polysaccharide quantification.
• To utilize particle motion tracking within a microfluidic electrophoresis platform.
• To overcome limitations of existing bioanalytical sensors and separation techniques.

Main Methods:

• Developed a microfluidic electrophoresis platform using Pluronic thermal gel.
• Incorporated fluorescent nanoparticles (200 nm diameter) for motion tracking.
• Tracked particle displacement induced by concentrated polysaccharide bands (20 kDa carboxymethyl dextran) under voltage.

Main Results:

• Established optimal operating conditions (gel concentration, temperature) for analysis.
• Optimized data processing strategies (exposure intervals, particle averaging, motion directionality) for sensitivity.
• Achieved a detection limit of 520 pM for 20 kDa sugar, a 10^6-fold improvement over UV-Vis absorbance.

Conclusions:

• Successfully integrated particle sensing with thermal gel electrophoresis for label-free polysaccharide quantitation.
• Demonstrated superior sensitivity and a broad quantitative range (0.5-5000 nM).
• Confirmed sensitivity dependence on polysaccharide molecular weight, with larger sugars yielding greater responses.