Lantern-like Hollow Nanoparticles with High-Efficiency Photothermal Property for the Point-of-care Detection of Illegal Additive

The detection of illegal additives in food or health products is of importance, as the excessive consumption of such products has detrimental effects on human health. Surface-enhanced Raman spectroscopy and liquid chromatograph-tandem mass spectrometry are widely employed for the detection of hazardous substances in food, however, their applicability for point-of-care test (POCT) is limited. In this work, a novel photothermal material, PdCu@Cu2O, was synthesized using polyhedron Cu2O as template and then doping with Pd nanoparticles by in-situ reduction. PdCu@Cu2O had a lantern-like hollow nanocage morphology with a core-shell structure that improved the refractive index of incident light, while the symmetric structure facilitated the strong absorption resonance, thus PdCu@Cu2O exhibited a high photothermal conversion efficiency of 46.4 %. Finally, a photothermal immunosensor was developed for the sensitive detection of aminopyrine in a range of 5×10−5-1×10−1 μg/mL, which can realize facile photothermal recognition using a miniaturized near-infrared lamp and handheld thermal imaging device. This portable device can easily transform the temperature signal to achieve target concentration, thus providing an effective way to visualize POCT detection in resource-limited areas.