All-in-one device for mapping the interactive effects of photodynamic therapy dosimetry in tumor gaseous microenvironment

Photodynamic therapy (PDT) elicits cell death, vascular damage, or/and anti-tumor host immune response upon activating the administered photosensitive drug by an appropriate light source. Because PDT is heavily depen-dent on tissue oxygen (O2) in essence, the concentration-dependent impact of O2 on tailoring cellular response to PDT remains an in-depth investigation. As a multifaceted modality, optimal combinations of photosensitizer (PS) concentration, light dose, and O2 delivery are critical to achieve ideal therapeutic outcomes. We herein present a fully integrated all-in-one device for the in vitro assessment of PDT efficacy synchronizing the quantitative control of three PDT disciplines simultaneously, aiming at 1) identifying the influence of varying gaseous microenvi-ronments on PDT; and 2) determining the contribution of each PDT factor and estimating the strength of their synergic effect. The gas-gradient-generating unit for contactless headspace O2 delivery and spatial light control filtering layer in our device could either work as a stand-alone module or combine to screen a range of exper-imental PDT parameters. By sweeping a total of 128 conditions over four 5-aminolevulinic acid (5-ALA) con-centrations, four light dosages, and eight O2 levels in one single experiment, we determined the main effects of the three key PDT agents and highlighted the interactive effect between 5-ALA and light after full-factorial statistical analysis. Our device is not only a versatile tool for predicting PDT efficacy during the translational study but also provides valuable multidimensional information for the interrelation between key PDT factors, which may expedite clinical PDT dosimetry and furnish new insights for the fundamental understanding of photobiological processes.