Abstract
Measurement methods of therapeutic polymer nanoparticles in the blood stream pre-sent issues regarding adequate selectivity and appropriate safety in complex environ-ments with high absorption coefficients, such as proteins and cells in the blood. In light absorption, the energy of photons can be converted into heat by the photothermal effect and re-emitted through luminescence as autofluorescence. In this study, we developed a microfluidic model to investigate the role of the photothermal effect and autofluores-cence in the measurement of fluorescence from polymer nanoparticles in the blood. The increase in blood temperature owing to the photothermal effect was observed using the laser induced fluorescence (LIF) spectroscopy technique. The detection limit of fluo-rescent polylactic acid (PLA) nanoparticles in whole blood was established 21 μg/mL based on the 3σ value. Polymer nanoparticle sensing in the blood is expected to support monitoring of therapeutic drug concentrations inside the body.
