A Simple Separation Method of the Protein and Polystyrene Bead-Labeled Protein for Enhancing the Performance of...

Area of Science:

• Biotechnology
• Microfluidics
• Biosensing

Background:

• Bead-based fluorescent sensors are crucial for diagnostics.
• Amyloid beta 42 protein is a key biomarker for neurodegenerative diseases.
• Efficient separation of target molecules and beads is vital for sensor accuracy.

Purpose of the Study:

• To demonstrate a dielectrophoresis (DEP)-based method for separating amyloid beta 42 protein from polystyrene (PS) beads.
• To enhance the performance of bead-based fluorescent sensors.
• To optimize microhole dimensions and DEP conditions for effective separation.

Main Methods:

• Simulated microhole diameters of 3 μm and 15 μm for DEP separation.
• Fabricated microholes using microelectromechanical systems (MEMS).
• Measured average fluorescence intensity (AIF) under varying voltage and time conditions to optimize PS bead allocation into the 15 μm hole.

Main Results:

• Optimized conditions for PS bead allocation into the 15 μm hole were 80 mV and 15 min, yielding a relative AIF of approximately 4.908 ± 0.299.
• Achieved effective separation of 2 nm protein and 30 nm PS beads in 3 μm and 15 μm microholes using DEP force.
• Demonstrated distinct AIF values for protein and PS beads in each microhole, confirming successful separation.

Conclusions:

• The DEP-based method effectively separates amyloid beta 42 protein and PS beads in microholes.
• This technique is applicable for verifying labeling efficiency in bead-based fluorescent sensors.
• The study highlights the potential of microfluidic DEP for improving biosensor performance and reliability.