MXene based flexible microheater for enhanced infrared imaging of cerebral blood flow

Infrared thermography technology is a noninvasiveness and real-time imaging method, it has attracted enormous attentions for blood flow imaging. However, the implementation of infrared thermography technology is still limited by the poor imaging quality caused by the low temperature discrimination between the target blood vessel and background. Herein, we reported a flexible and low-cost MXene based photothermal microheater for enhancing the infrared imaging of blood flow. In the experiment, MXene films with specific thickness was prepared by vacuum filtering different concentrations of MXene colloidal solutions. Thereafter, the microheaters were fabricated by assembling the MXene films on the PU tape/PDMS substrate, and then sealed with another layer of pure PDMS film on the top of MXene film. The photothermal performance of the microheaters were evaluated by using an 808-nm laser as the exciting source. Experimental results show that the optimal microheater (MXene content: 17.5 ​mg) can reach a safe temperature of 41.5 ​°C with 43.9 ​s under the light irradiation of 100 ​mW·cm⁻². Moreover, it can be stabilized at the equilibrium temperate for over 25 ​min. Finally, the above optimal microheater was used to accurately heat the simulated blood vessel. It shows that temperature difference of 3.3 ​°C can be induced between the heated blood vessel and environment. As a result, it significantly enhances the quality of the infrared imaging of the blood flow in the simulated vascular network.