Cationic polymer-based plasmonic sensor array that discriminates proteins

Area of Science:

• Analytical Chemistry
• Materials Science
• Biotechnology

Background:

• Traditional sensing methods often rely on specific interactions, limiting their scope.
• Nonspecific interactions offer a promising avenue for developing versatile sensing platforms.
• Gold nanoparticles (Au NPs) are widely used in colorimetric sensing due to their distinct optical properties.

Purpose of the Study:

• To develop a colorimetric sensor array for protein discrimination.
• To overcome the limitations of lock-and-key sensing strategies.
• To utilize diverse interactions between cationic polymers and proteins for sensing.

Main Methods:

• A sensor array was constructed using three cationic polymers: polydiallyl dimethylammonium chloride (PDDA), chitosan (CTS), and cetyltrimethylammonium bromide (CTAB).
• Gold nanoparticles (Au NPs) were employed as the signaling element, with their aggregation behavior modulated by interactions with the polymers and proteins.
• Colorimetric changes and absorbance shifts of Au NPs were analyzed.
• Linear discrimination analysis (LDA) was used for data interpretation and protein identification.

Main Results:

• The sensor array demonstrated diverse colorimetric responses based on the interactions between cationic polymers and proteins.
• Seven different proteins were successfully discriminated visually at a concentration of 20 nM.
• The array's practicality was validated through the identification of proteins in human serum samples without overlap.

Conclusions:

• The developed colorimetric sensor array offers a robust method for protein discrimination.
• Nonspecific interactions with cationic polymers provide a powerful tool for sensing applications.
• This approach has potential for practical applications in biological fluid analysis.