Label-free biomarker detection from whole blood

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Diagnostics

Background:

• Label-free nanosensors offer potential for low-cost, rapid, specific, and sensitive point-of-care disease diagnosis.
• Detecting biomarkers in complex physiological fluids like blood is challenging due to biofouling and non-specific binding, often requiring purified buffers that reduce clinical relevance.

Purpose of the Study:

• To overcome limitations of nanosensor detection in physiological fluids by integrating sample purification with sensing.
• To develop a two-stage approach for isolating nanosensors from complex sample matrices and enhancing biomarker detection.

Main Methods:

• A microfluidic purification chip was designed to capture multiple biomarkers from blood samples.
• Captured biomarkers were washed and released into a purified buffer for detection by a silicon nanoribbon detector.
• This integrated system performed both purification and label-free detection.

Main Results:

• The two-stage approach successfully isolated the silicon nanoribbon detector from the complex whole blood environment.
• Biomarker pre-concentration by the purification chip reduced the minimum required sensitivity for detection.
• Specific and quantitative detection of two model cancer antigens was achieved from a 10 microliter whole blood sample in under 20 minutes.

Conclusions:

• This study demonstrates the first successful use of label-free nanosensors with unprocessed physiological solutions.
• The integrated purification and detection system significantly enhances the clinical applicability of nanosensor technology.
• This technology is positioned for rapid translation to clinical settings for point-of-care diagnostics.