A simple and cost-effective solid-phase protein nano-assay using polyacrylamide-coated glass plates

Area of Science:

• Biochemistry
• Analytical Chemistry
• Proteomics

Background:

• Accurate protein quantification is crucial for various biological and chemical analyses.
• Existing protein assays often involve trade-offs between sensitivity, cost, and ease of documentation.
• Solid-phase assays offer potential for simplified sample handling and analysis.

Purpose of the Study:

• To develop a simple, sensitive, and cost-effective solid-phase protein nano-assay.
• To combine the advantages of "on-membrane" and "in-gel" protein staining techniques.
• To establish a reliable method for protein estimation in small sample volumes.

Main Methods:

• Utilized inexpensive, transparent polyacrylamide gel (PAAG)-coated glass plates as a solid support.
• Adapted conventional "on-filter" assay principles to the PAAG plate format.
• Developed and employed a low-cost colloidal Coomassie brilliant blue G-250 (CBB G-250) staining protocol.

Main Results:

• The PAAG plate assay allows for sensitive protein estimation using only 1 μl of sample.
• The assay is compatible with standard laboratory gel documentation systems.
• The colloidal CBB G-250 protocol achieved a detection limit of up to 2 ng of protein, even with basic imaging equipment.

Conclusions:

• The PAAG plate assay provides a versatile, sensitive, and cost-effective solid-phase method for protein quantification.
• This assay is particularly suitable for proteomic applications and scenarios requiring rapid, easily documented protein analysis.
• The developed assay offers a practical alternative to conventional protein estimation techniques.