A Nanosensor Platform for Biologging in Marine Animals.

Biologging has significantly advanced ecological biology by enabling the collection of data from free-roaming animals in their natural habitats. Traditionally, these measurements have largely been limited to temperature, pressure, and movement. Incorporating physiological data of animal biomarkers could yield valuable orthogonal data sets, providing a more nuanced understanding of organisms in the context of their environments and behaviors. Despite this potential, successful collection of such biochemical information remains absent and thus motivates new sensor platforms. Toward this end, we explore the hardware and nanosensor optimization of animal implantable sensors for tracking hormone levels in marine animals. The transducer element is based on polymer-wrapped single-walled carbon nanotubes that act as nanosensors embedded within a biocompatible poly(ethylene glycol) diacrylate hydrogel. This work investigates the performance of the nanosensor hydrogel under various temperatures, illumination conditions, and nanoparticle concentrations in the hydrogel. We further prototype a miniaturized fluorescent system for integration into existing, commercially available acoustic tags widely used in marine biology studies. We demonstrate a baseline of 100 nM for the detection limit of progesterone as an example of an important hormone in marine animals using the integrated nanosensor hydrogel in this platform. Further improvement is possible with optimization of the signal-to-noise ratio via hardware development. This developed form-factor will complement the presently collected data by providing insights into the physiological state of the animals in the context of their behavior and environments.