Digital SERS bioanalysis of single-enzyme biomarkers

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Spectroscopy

Background:

• Digital bioanalysis offers single-molecule detection but conventional fluorescence methods have limitations in molecular selectivity and multiplexing.
• Existing techniques struggle to simultaneously analyze multiple targets and differentiate closely related biomolecules.

Purpose of the Study:

• To develop a novel digital bioanalysis platform using surface-enhanced Raman scattering (SERS) for highly selective and multiplexed detection of enzyme biomarkers.
• To overcome the limitations of fluorescence-based methods in terms of molecular selectivity and simultaneous multi-target analysis.

Main Methods:

• Development of a digital bioanalysis platform integrating SERS spectroscopy with microchamber arrays functionalized with silver nanoparticles.
• Utilizing SERS for million-fold signal amplification of single-enzyme reaction products.
• Leveraging distinct Raman spectral signatures for precise digital counting and multiplexed quantification.

Main Results:

• The SERS-based platform achieved a million-fold signal amplification, enabling precise digital counting of enzyme biomarkers.
• Demonstrated high molecular selectivity and multiplexing capability by detecting and distinguishing acetylcholinesterase (AChE) and butyrylcholinesterase.
• Achieved femtomolar-level sensitivity for multiplexed biomarker quantification and successfully quantified AChE in human cerebrospinal fluid within 8.5 minutes.

Conclusions:

• The developed SERS digital bioanalysis platform provides enhanced molecular selectivity and multiplexing capability, serving as a valuable alternative to fluorescence-based methods.
• The platform demonstrates significant potential for clinical diagnostics, particularly in differentiating dementia types through precise enzyme level quantification in complex biological samples.
• This study expands the scope of digital bioanalysis, enabling high-precision quantification of multiple biomarkers in complex matrices.