Intelligent Visualization of Single Microbead Bubbling Enables Attomolar Protein Quantification

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Point-of-Care Diagnostics

Background:

• Accurate quantification of low-abundance proteins in biofluids is crucial for point-of-care testing and disease monitoring.
• Existing methods often lack portability, affordability, and the required sensitivity for early disease detection.

Purpose of the Study:

• To develop a facile, low-cost, and highly sensitive portable immunoassay platform for protein analysis.
• To enable ultrasensitive protein detection down to attomolar (aM) levels using a novel signal readout.

Main Methods:

• A cellphone-based portable immunoassay platform utilizing a single microbead (SMB) as an immunocarrier.
• Platinum nanoparticle (PtNP)-enhanced immunocomplexes on the SMB catalyze oxygen bubble formation.
• A cellphone-attached lens and image analysis algorithm for bubble imaging and quantification.

Main Results:

• The SMB bubbling visualization mechanism achieved superenrichment of target-mediated immunocomplexes, significantly boosting sensitivity.
• Ultrasensitive protein detection down to aM levels was demonstrated.
• An all-in-one cellphone application streamlined the entire detection process.

Conclusions:

• The proposed intelligent platform offers a highly sensitive and cost-effective method for critical biomarker testing.
• This technology paves a new way for cellphone-enabled portable biosensing and in-field disease screening.