Microwave-induced activation of phase-change nanodroplets using a directional ultrawideband microstrip antenna
Phys. Rev. Applied 26, 014010 – Published 6 July, 2026
DOI: https://doi.org/10.1103/vr64-pkdh
Abstract
Phase-change nanodroplets (PCNDs) are stimuli-responsive agents with growing relevance in applications ranging from materials science and smart systems to microfluidics, decontamination, and biomedical diagnostics and therapy. Targeted activation of PCNDs, where the liquid core transitions into a gas phase to form microbubbles, can be achieved by using external energy sources. While ultrasound and laser-based modalities are typically used for PCND activation, their limited penetration depth in many complex materials and structures poses challenges for deeper targets. In this study, a new microwave-induced nanodroplet activation mechanism is proposed, and its feasibility is demonstrated using an ultrawideband microwave antenna. The experiments were designed to evaluate the effect of microwave exposure on lipid-shell perfluoropentane nanodroplets across a temperature range of 20–70 °C and at varying microwave exposure durations. Findings of this study show that longer duration microwave exposure results in a higher number of PCND activations at lower temperatures without any bulk temperature increase, where statistically significant differences () are observed for the 5-min microwave exposure group in comparison with the control group at 50 °C. This statistical significance implies that the microwave exposure reduces the activation threshold of PCNDs, offering a promising approach for noncontact, controlled, and targeted PCND activation in settings where conventional energy-delivery methods are limited.
