Graphene-based rapid and highly-sensitive immunoassay for C-reactive protein using a smartphone-based colorimetric...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Human C-reactive protein (CRP) is a crucial biomarker for infection and inflammation.
• Existing immunoassay methods can be complex and require specialized equipment.
• There is a need for rapid, sensitive, and user-friendly CRP detection methods.

Purpose of the Study:

• To develop a novel, sensitive, and stable immunoassay for human C-reactive protein (CRP).
• To utilize graphene nanoplatelets (GNP) and smartphone-based detection for simplified CRP quantification.
• To validate the performance of the developed immunoassay in clinical samples.

Main Methods:

• Functionalization of polystyrene microtiter plates (MTP) with graphene nanoplatelets (GNP) and 3-aminopropyltriethoxysilane (APTES).
• Covalent attachment of anti-human CRP antibodies to the GNP-functionalized MTP surface.
• One-step kinetics-based sandwich immunoassay procedure monitored by a smartphone colorimetric reader.
• Detection of CRP in spiked whole blood, plasma, and clinical plasma samples.

Main Results:

• The immunoassay demonstrated high sensitivity with a limit of detection of 0.07 ng/mL and a limit of quantification of 0.9 ng/mL.
• Accurate CRP detection was achieved in diluted human whole blood, plasma, and clinical patient samples.
• Results correlated well with conventional immunosorbent assays and accredited analyzer-based methods.
• The antibody-bound GNP-functionalized MTPs showed stability for at least 6 weeks under refrigerated storage.

Conclusions:

• A novel, sensitive, and stable immunoassay for human CRP has been successfully developed.
• The integration of graphene nanoplatelets and smartphone-based detection offers a promising platform for point-of-care diagnostics.
• This method provides a reliable and efficient alternative for CRP quantification in clinical settings.