PAMAM-Functionalized Paper as a New Substrate for the Paper Spray Mass Spectrometry Measurement of Proteins

Area of Science:

• Analytical Chemistry
• Materials Science
• Biochemistry

Background:

• Paper spray mass spectrometry (PS-MS) is a sensitive analytical technique.
• Protein analysis in biofluids requires efficient extraction and high sensitivity.
• Polyamidoamine (PAMAM) dendrimers offer unique surface chemistry for molecular interactions.

Purpose of the Study:

• To develop and optimize PAMAM dendrimer-functionalized paper for enhanced protein analysis via PS-MS.
• To evaluate the sensitivity, linearity, and precision of the functionalized paper for protein quantification.
• To assess the potential of this method for clinical diagnosis, specifically microalbuminuria.

Main Methods:

• Surface functionalization of paper substrates with PAMAM dendrimers.
• Protein extraction from biofluids using functionalized paper strips.
• Sample preparation involving dipping in acetonitrile and drying.
• Analysis of proteins using paper spray mass spectrometry (PS-MS).
• Optimization and comparison with unmodified paper strips.

Main Results:

• PAMAM-functionalized paper showed significantly increased sensitivity for proteins: 6-fold for albumin, 11-fold for hemoglobin, 7-fold for insulin, and 2-fold for lysozyme.
• Excellent analytical performance for urinary albumin: linearity (R² > 0.99), low limit of detection (LOD) of 1.1 μg mL⁻¹, limit of quantification (LOQ) of 3.8 μg mL⁻¹, precision <10%, and recovery 70-83%.
• Successful quantification of urinary albumin in patient samples, demonstrating potential for microalbuminuria diagnosis.

Conclusions:

• PAMAM dendrimer functionalization is a highly effective strategy for enhancing protein sensitivity in PS-MS.
• The developed method offers a sensitive, precise, and reliable approach for protein quantification in biofluids.
• This technique holds significant promise for advancing clinical diagnostics through the analysis of disease-related proteins.