Magnetic Nanoparticles as Label-Free Dual-Function Nanoheaters and Nanothermometers

TL;DR

This paper introduces cobalt ferrite magnetic nanoparticles that can simultaneously generate heat and provide real-time temperature measurements at the nanoscale without additional labels, advancing thermal therapy techniques.

Contribution

The study presents a novel, label-free nanoplatform that combines dual-functionality of heating and thermometry using magnetic nanoflowers, simplifying implementation for thermal therapies.

Findings

Magnetization cycles vary with temperature, enabling nanothermometry.

Nanoparticles maintain thermometric function after surface functionalization.

Cobalt ferrite nanoparticles effectively generate heat under near-infrared irradiation.

Abstract

Heat generation and temperature reading at the nanoscale have attracted increasing attention due to their direct relevance in thermal therapeutic approaches. Consequently, huge progress has been made toward the design of dual-function nanoplatforms that integrate heating and thermometry capabilities at the nanoscale. However, in most cases, dual nanoheater nanothermometer platforms rely either on specifically engineered materials or on complex readout schemes, which limits translational potential due to complex implementation procedures. To overcome these challenges, we present a methodology for directly extracting temperature information based on dynamical magnetization measurements of cobalt ferrite magnetic nanoflowers. We demonstrate that these nanocrystals monitor temperature changes through variations in their magnetization cycles measured under alternating magnetic fields. Importantly, this thermometric functionality is preserved after surface functionalization and under chemical variations in the nanoparticle environment. Interestingly, we show that we can simultaneously generate heat and report temperature changes within the same agent. This is thanks to the photothermal conversion of cobalt ferrite nanoparticles subjected to near infrared irradiation and the tight reported relationship between magnetization dynamics and Brownian relaxation. Together, these results establish cobalt ferrite magnetic nanoparticles as a label-free platform for simultaneous heat generation and intrinsic temperature readout, enabling real-time nanoscale thermal control.