Infrared-driven pyroelectric effect in magnetoelectric sensor for suspended on-chip magnetic nanoparticles quantification

Abstract

Precise and real-time quantification of suspended magnetic nanoparticles (MNPs) is essential for augmenting the efficacy of the present MNP-based lab-on-a-chip systems. Existing MNP quantification techniques use bulky external electromagnets, which make such techniques expensive, energy-inefficient, and result in significant side effects on the surrounding healthy tissues. Here, we report on the development of an infrared-driven, Ni/lead magnesium niobate–lead titanate (PMN–PT) magnetoelectric (ME) heterostructure-based sensor that enables rapid assessment of the suspended MNPs in a fluidic environment without using an external magnetic field. The injected MNPs are captured by the generated magnetic field gradient of the Ni thin film. Subsequently, the optothermal-pyroelectric property of the underlying PMN–PT layer is utilized to quantitatively assess the MNPs' concentration. Under the incident infrared pulse at zero bias voltage, the device shows different transient photocurrent responses against varied MNP concentrations with a sensitivity of 0.29 nA mg−1 ml and a response time of less than 2 s. Such a ME device can improve the efficacy of current ME-based lab-on-a-chip systems, where a single device can capture, manipulate, as well as quantitatively assess the MNPs efficiently for critical biomedical applications such as drug delivery, drug regulation, and hyperthermia.