Multifunctional Fe 3 O 4 @Au supraparticle as a promising thermal contrast for an ultrasensitive lateral flow immunoassay

• Published in: Talanta (Oxford) 2021-01, Vol.222, p.121478
• Main Authors: Zhang, Ting, Lei, Lingli, Tian, Meiling, Ren, Junjie, Lu, Zhisong, Liu, Yang, Liu, Yingshuai
• Format: Article
• Language: English
• Subjects: Antibodies; Gold; Immunoassay; Limit of Detection; Magnetite Nanoparticles
• ISSN: 1873-3573

An ultrasensitive lateral flow immunoassay (LFIA) strip has been developed based on a multifunctional photothermal contrast Fe O @Au supraparticle (Fe O @Au SP) for quantitative Ochratoxin A (OTA) detection. The Fe O @Au SP composite not only shows a better photothermal effect over Fe O and gold nanoparticles, but possesses magnetic property and excellent ability to directly adsorb protein (antibody). Under 808 nm irradiation, photothermal images of the test strips are recorded by a portable Infrared thermal camera. A quantitative analysis is easily achieved based on the thermal changes, which are proportional to the concentrations of analytes. Under an optimal condition, a wide linear detection range from 1 pg mL⁻ to 1μgmL⁻ and a limit of detection (LOD) at 0.12 pg mL⁻ have been achieved with OTA as a model analytes. The practical application potential has also been validated by detection of OTA in spiked corn, peanut, and soybean extractives with overall recoveries ranging from 98.6% to 115% and coefficient of variations (CVs) between 6.06% and 12.73%. The photothermal LFIA renders a rapid, sensitive, and quantitative bio-/chemo-sensing platform with only a portable laser source and a thermal camera.