Fig. 2: Bioengineering and characterization of PMCs.
From: Engineering micro oxygen factories to slow tumour progression via hyperoxic microenvironments
a Imaging of constructed PMCs. The empty MCs, MCs containing algal cells (e-S. sp. 6803@MCs) and fully constructed PMCs were subjected to imaging by upconversion luminescence microscopy at 980 nm. The edge of MCs is described by white outline. b A heatmap presenting O2 production by PMCs with different formulations. Algal cells at 107–1011 cell/mL, UCNPs at 0–100 mg/mL, and 1 mL of alginate sodium were mixed together to prepare different formulations of PMCs by an electrostatic droplet generation system. The resulting PMCs were exposed to 900 mW/cm2 NIR radiation for 20 min to measure O2 levels by a portable dissolved oxygen metre. c Visualization of synthesized oxygen species in PMCs by DCFH staining. PMCs, e-S. sp. 6803@MCs and UCNP@MCs cultured in the dark for 12 h were incubated with 10 μg/mL DCFH for 10 min and then exposed to 300 mW/cm2 980 nm NIR radiation for 0, 1, 3 and 10 min. The treated microspheres were immediately visualized by confocal microscopy at 488 nm excitation. The edge of MCs is described by white outline. d Schematic image to show pO2 detection in tumours. e Measurements of the partial pressures of oxygen (pO2) in the cores of tumours at different time points. Data are presented as means ± SD derived from three tumours. f visual display of pO2 in tumours. A Clark oxygen electrode was used to measure pO2 in mouse breast tumours received saline, PMC, NIR, hyperbaric oxygen (60%) and NIR-PMC treatments. The pO2 values were recorded in tumours at 5 mm depths for 7 days or different depths of tumours at 1 h post NIR-PMC treatments. The pO2 values at the largest cross-section of tumours were integrated by Python for constructions of the heatmaps. The edge of tumour is described by black outline. Source data are provided as a Source data file.
