Sensitive Detection of Exosomal Biomarkers via a Drop-Shaped Porous Microfluidic Chip for Potential Diagnosis of Alzheimer's Disease.

Alzheimer's disease (AD), a progressive and irreversible neurodegenerative disorder, underscores the critical need for developing noninvasive early diagnostic methods. In recent years, blood-exosome-based diagnostics have emerged as a promising approach, as exosomes carry disease-specific biomarkers. However, sensitive detection of AD biomarkers in serum exosomes remains technically challenging due to the low abundance of target molecules and the complexity of biological samples. To address this limitation, we developed an integrated platform combining a novel drop-shaped porous microfluidic chip for exosome enrichment with a rolling circle amplification (RCA)-based immunomagnetic bead detection system. The microfluidic chip, designed with a unique architecture and enriched with abundant binding sites, enables the selective capture and enrichment of exosomes from complex serum samples, significantly improving the recovery rate and purity of exosomes. Meanwhile, the RCA-based detection system allows precise quantification of exosomal proteins (Aβ42 and p-Tau181), converting biomarker levels into measurable fluorescence signals. This strategy achieves highly sensitive and specific detection of AD biomarkers, facilitating the effective differentiation of AD patients. Our platform offers a noninvasive, scalable solution for early AD diagnosis, holding significant potential for clinical applications and timely intervention.