I study the mechanobiology of living organisms using biocompatible optical nanoprobes. Lanthanide doped alkaline earth based nanoparticles upconvert infrared light to the visible region, providing a robust optical signal without the background autofluorescence that plagues conventional in-vivo fluorescence measurements. By characterizing the pressure sensitivity of this upconversion signal inside live C. elegans nematode worms, I hope to provide biologists and clinicians a novel tool to study the physiology and pathology of human cells and tissue.