BME Frontiers / 2021 / Article / Fig 4

Research Article

Bioresorbable Multilayer Photonic Cavities as Temporary Implants for Tether-Free Measurements of Regional Tissue Temperatures

Figure 4

Bioresorption characteristics: (a) height profiles and AFM topographical images of a multilayer photonic cavity patterned into a square pad with sloping sidewalls, measured at various times after immersion in phosphate-buffered saline (PBS) () at 37°C; (b) 3D-rendered computed tomography (CT) images of mice collected over 2 weeks after implantation of a device, showing gradual disappearance of W coatings on the bioresorbable photonic cavity, as an approximate representation of the bioresorption of the device; (c) measured reflection spectra of a multilayer photonic cavity during its immersion in PBS solution () at 37°C; (d) in vivo biodistribution of tungsten (W) coatings from a bioresorbable photonic cavity. Here, the device consists of a multilayer photonic cavity structure (, ) supported on a 10 μm thick PLGA film. Implantation was in the subcutaneous region near the flank region ( biologically independent mice), with comparisons to control animals ( biologically independent mice). Euthanizing three experimental mice ( biologically independent mice) at weeks 1, 2, 3, and 5 enabled analysis of biodistribution of implanted bioresorbable photonic cavities. Inductively coupled plasma mass spectrometry (ICP-MS) defines the concentrations of W, in blood and organs (brain, heart, kidney, liver, lung, muscle, and spleen) explanted at 1, 2, 3, and 5 weeks after implantation.