Reusable Microfluidic Chambers for Single-Molecule Microscopy.

Area of Science:

• Biophysics
• Surface Chemistry
• Microfluidics

Background:

• Single-molecule experiments require consistent microfluidic chamber environments.
• Surface passivation and cleaning are laborious and often lead to variations in nonspecific binding and background signals.
• Reusing chambers without surface degradation is crucial for practical and fundamental advancements.

Purpose of the Study:

• To develop an effective and non-damaging method for resetting microfluidic chambers for single-molecule studies.
• To enable repeated reuse of chambers by efficiently removing surface-bound molecules.
• To validate the surface integrity and functionality after multiple recycling cycles.

Main Methods:

• Utilized photocleavable biotin (PC-biotin) for attaching molecules like DNA, proteins, lipids, and nanoparticles to chamber surfaces.
• Exposed chambers to specific wavelength UV light for 5 minutes to cleave PC-biotin and remove bound molecules.
• Assessed surface quality by measuring nonspecific binding of fluorescently labeled DNA and proteins and evaluating DNA secondary structure and protein activity recovery.

Main Results:

• Demonstrated successful resetting and recycling of microfluidic chambers at least 10 times using PC-biotin and UV light.
• Confirmed that a 5-minute UV exposure at a specific wavelength effectively removes all bound molecules without harsh chemicals.
• Showed no detectable degradation of surface quality, with consistent performance in subsequent experiments.

Conclusions:

• Photocleavable biotin combined with UV light offers an efficient, cost-effective, and non-damaging method for resetting microfluidic chambers.
• This approach significantly simplifies chamber preparation and enhances the reproducibility of single-molecule experiments.
• The method's adaptability and compatibility with widespread biotin-streptavidin chemistries make it broadly applicable to various single-molecule research areas.