Colloidally stable silver-lignin hybrid nanoparticles hold many prospective applications such as sensory materials. Herein we used Ag-HLNP for the detection of hydrogen peroxide (Movie S1). These particles offer a facile means to quantify hydrogen peroxide with concentration as low as 0.05 mM in colloidal state using UV-Vis spectroscopy (Figure ). There are not many prior studies combining lignin and silver nanoparticles for sensors. Among those, lignin has merely been used as a reducing and capping agent, i.e., not as a spherical nanoparticle template.