Analysis and management of thermal loads generated in vivo by miniaturized optoelectronic implantable devices.

Miniaturized implantable optoelectronic technologies for in vivo biomedical applications are gaining interest, but require strict thermal management for safe operation. Here, we introduce a comprehensive framework combining analytical solutions and numerical modeling to estimate and manage thermal effects of optoelectronic devices. We propose Green's functions to analytically solve temperature distributions in tissue from a point source with coupled thermal-optical power, capturing the influence of critical tissue properties and spatiotemporal parameters. Integrating the Green's function derives temperature distributions for sources with definable geometry. Numerical modeling defines scaling factors to account for variations in radiation patterns and material designs, enabling direct performance comparisons across systems. Guided by this framework, iterative optimization of a filamentary optogenetic probe for deep brain stimulation significantly reduces thermal loads while preserving typical behaviors in freely moving mice. Experimental validation through in vitro and in vivo characterization demonstrates scalable strategies to overcome thermal challenges in advanced bio-optoelectronic systems.