A portable device with low-power consumption for monitoring mouse vital signs during in vivo photoacoustic imaging and photothermal therapy

Abstract

Objective: The aim of this study was to monitor the physiological changes and cytotoxic effects of exogenous contrast agents during photoacoustic imaging (PAI) and photothermal therapy (PTT). In this paper, a low-power telemetric device for mouse vital signs monitoring was designed and demonstrated. Approach: The power consumption was optimized through hardware and software co-design with a 17% increased operating time compared with typical operation. To demonstrate the feasibility of the monitoring device, PAI and PTT experiments with chitosan-polypyrrole nanocomposites (CS-PPy NCs) as exogenous contrast agents were conducted. Herein, the physiological variation in groups of mice with different CS-PPy NC concentrations was observed and analyzed. Main results: The experimental results indicated the influence of CS-PPy NCs and anesthesia on mouse vital signs in PAI and PTT. Additionally, the association between core temperature, heart rate, and saturation of peripheral oxygen (SpO2) during PAI and PTT was shown. The strong near-infrared absorbance of exogenous contrast agents could account for the increase in mouse core temperature and tumor temperature in this study. Furthermore, high cross-correlation values between core temperature, heart rate, and SpO2 were demonstrated to explain the fluctuation of mouse vital signs during PAI and PTT. Significance: A design of a vital signs monitoring device, with low power consumption, was introduced in this study. A high cross correlation coefficient of mouse vital signs and the effects of CS-PPy NCs were observed, which explained the mouse physiological variation during the PAI and PTT experiments.