Programmable Plasmonic Hydrogel Thermometers Actuated by DNA Breathing

Nanothermometry explores the use of temperature-dependent properties of materials for remote and sensitive thermal readout at the nanoscale. The currently established nanothermometers are largely limited by uncontrollable nanoparticle flocculation, complex experimental setup, and narrow working temperature range. Here it is shown that gold nanoparticles (e.g., spheres, rods) embedded in a hydrogel can afford sensitive, durable, and range-tunable temperature sensing via the terminal breathing of the nanoparticle surface-grafted DNA. The realization of the plasmonic hydrogel thermometer with a thermal sensitivity of ≤2 °C relies on the dynamically modulable interparticle spacing by thermo-responsive terminal base pairing/unpairing of the surface DNA. By altering the alcoholic ratio of the hydrogel, the temperature-response range can be continuously regulated based on solvent-mediated DNA base pairing. Compared with the colloidal counterpart, importantly, the hydrogel thermometer exhibits greatly improved thermal sensing capability (e.g., repeatability ≥50 times) while possessing excellent durability. Given the excellent durability, high sensitivity, and programmable temperature response range, the thermometers actuated by DNA breathing for advanced uses in human sensing and optoelectronics are within reach.