An ultrasensitive lateral flow immunoassay (LFIA) strip has been developed based on a multifunctional photothermal contrast Fe₃O₄@Au supraparticle (Fe₃O₄@Au SP) for quantitative Ochratoxin A (OTA) detection. The Fe₃O₄@Au SP composite not only shows a better photothermal effect over Fe₃O₄ 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⁻¹ to 1μgmL⁻¹ and a limit of detection (LOD) at 0.12 pg mL⁻¹ 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.

基于多功能光热造影剂Fe ₃ O ₄ @Au超颗粒（Fe ₃ O ₄ @Au SP）开发了一种超灵敏侧向免疫测定（LFIA）试纸，用于定量检测O曲霉毒素A（OTA）。Fe ₃ O ₄ @Au SP复合材料不仅表现出比Fe ₃ O ₄更好的光热效应和金纳米颗粒，但具有磁性和直接吸附蛋白质（抗体）的出色能力。在808 nm的辐射下，通过便携式红外热像仪记录测试条的光热图像。根据与分析物浓度成正比的热变化，可以轻松实现定量分析。下的最佳条件，一个宽的线性检测范围从1微克mL⁻ ¹至1μgmL⁻ ¹在0.12微克和检测限（LOD）mL⁻ ¹OTA作为分析物的模型已经实现。通过在加标的玉米，花生和大豆提取物中检测OTA，也验证了其实际应用潜力，其总回收率在98.6％至115％之间，变异系数（CV）在6.06％至12.73％之间。仅使用便携式激光源和热像仪，光热LFIA即可提供快速，灵敏且定量的生物/化学传感平台。