A graphene aptasensor for biomarker detection in human serum

Area of Science:

• Nanotechnology
• Biosensing
• Materials Science

Background:

• Biomarker detection in human serum is crucial for diagnostics.
• Existing methods often require sample dilution or desalting, complicating analysis.
• Graphene-based field-effect transistors offer potential for sensitive biosensing.

Purpose of the Study:

• To develop an affinity graphene nanosensor for label-free biomarker detection in undiluted, non-desalted human serum.
• To achieve specific and sensitive detection of biomarkers using aptamer functionalization.
• To demonstrate the nanosensor's capability using human immunoglobulin E (IgE) as a model biomarker.

Main Methods:

• Fabrication of a field-effect transistor using graphene as the conducting channel.
• Functionalization of the graphene surface with polyethylene glycol (PEG) and a biomarker-specific aptamer.
• Detection of biomarker binding via changes in graphene conductivity in an optimized buffer.
• Utilizing the PEG layer to minimize nonspecific adsorption and enhance aptamer accessibility.

Main Results:

• The graphene nanosensor specifically detected human immunoglobulin E (IgE) in serum.
• Detection was achieved in undiluted and non-desalted serum samples.
• The sensor demonstrated a high sensitivity with a resolution of 14.5 pM and a limit of detection of 47 pM for IgE.
• The device operated within a concentration range of 50 pM to 250 nM for IgE.

Conclusions:

• The developed affinity graphene nanosensor enables sensitive and specific label-free biomarker detection in complex biological samples like human serum.
• The integration of PEG and aptamers on graphene is an effective strategy for enhancing biosensor performance.
• This technology holds promise for simplified and efficient diagnostic applications.