Fe 3 O 4 -Au Core–Satellite Nanoparticles as Direct Colorimetric Reporters in a Smartphone-Quantified Lateral Flow Immunoassay for Prostate-Specific Antigen
This study demonstrates that Fe₃O₄/Au core–satellite magnetic particles, optimized for intermediate extinction to balance signal intensity and dynamic range, serve as high-contrast direct colorimetric reporters enabling a rapid, smartphone-quantified lateral flow immunoassay for prostate-specific antigen in undiluted human serum without requiring external excitation or signal amplification.