Controlled antibody release from gelatin for on-chip sample preparation.

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• On-chip sample preparation is crucial for point-of-care diagnostics.
• Controlled reagent release from microfluidic devices is essential for diagnostic applications.

Purpose of the Study:

• To investigate the release kinetics of fluorophore-conjugated antibodies from gelatin layers.
• To identify methods for controlling reagent release times in microfluidic chips.

Main Methods:

• Studied antibody release from varying thicknesses of gelatin layers (0.25–1.5 μm).
• Analyzed release kinetics using a diffusion model.
• Investigated the impact of preparation conditions (drying temperature/humidity), antibody size, and ionic strength on release rates.

Main Results:

• Antibody release followed a diffusion model with diffusivity of 0.65 μm²/s.
• Release times ranged from approximately 20 s to 650 s.
• Release kinetics were tunable by modifying gelatin preparation, antibody size, and ionic strength.

Conclusions:

• Gelatin layers offer controllable reagent release for microfluidic diagnostic devices.
• Understanding release kinetics allows for optimized reagent distribution, as demonstrated in cell counting chambers for homogeneous cell staining.