A "chemical nose" biosensor for detecting proteins in complex mixtures

Area of Science:

• Biomolecular analysis
• Nanotechnology applications
• Medical diagnostics

Background:

• Proteins play a crucial role in disease pathogenesis.
• Conventional protein assays (ELISA, mass spectrometry) are costly and complex.
• There is a need for accessible, quantitative protein detection methods.

Purpose of the Study:

• To develop and apply a "chemical nose" colorimetric sensor for protein analysis.
• To detect, quantify, and identify single proteins, mixtures, and proteins in human serum.
• To demonstrate a cost-effective and simplified alternative to existing protein assays.

Main Methods:

• Utilized a mixture of spherical and branched gold nanoparticles.
• Investigated interactions with six model proteins (BSA, HSA, IgG, fibrinogen, lysozyme, hemoglobin).
• Analyzed colorimetric changes (absorption spectra) for protein detection and quantification.

Main Results:

• Generated distinguishable, concentration-dependent absorption spectra for proteins at nanomolar levels.
• Demonstrated sensitivity to the relative abundance of proteins in mixtures.
• Successfully differentiated human serum samples with and without elevated immunoglobulin G (IgG).

Conclusions:

• The gold nanoparticle sensor provides a sensitive and specific method for protein analysis.
• This approach simplifies complex protein quantification in biological samples.
• The technology holds promise for accessible clinical diagnostics and research applications.