Conducting polymers with the capability of photothermal conversion extend the application of near-infrared light (NIR), satisfying the demands of less toxicity, easy availability, and high flexibility for NIR-sensitive materials. The improvement of light use efficiency is still urgent and challenging. In this work, an ultra-NIR-sensitive biocompatible porous particle composed of a polylactic acid matrix and polypyrrole nanoparticles is prepared via a one-step double-emulsion method. It is revealed that the light absorption of polyprryole is effectively improved within the porous structure. This particle is exploited as a cost-effective sensing material in terms of its conductivity change for preparing paper-based NIR light sensors. Moreover, the microspheres act as a guardian to encapsulate and lock excess nucleic acids which is useful for preventing inflammatory diseases.