Micheva Maria, Baluschev Stanislav, Landfester Katharina
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Faculty of Physics, Sofia University "St. Kliment Ohridski", 5 James Bourchier Blvd., 1164 Sofa, Bulgaria.
Nanomaterials (Basel). 2025 Jan 16;15(2):123. doi: 10.3390/nano15020123.
Environmental changes, such as applied medication, nutrient depletion, and accumulation of metabolic residues, affect cell culture activity. The combination of these factors reflects on the local temperature distribution and local oxygen concentration towards the cell culture scaffold. However, determining the temporal variation of local temperature, independent of local oxygen concentration changes in biological specimens, remains a significant technological challenge. The process of triplet-triplet annihilation upconversion (TTA-UC), performed in a nanoconfined environment with a continuous aqueous phase, appears to be a possible solution to these severe sensing problems. This process generates two optical signals (delayed emitter fluorescence (dF) and residual sensitizer phosphorescence (rPh)) in response to a single external stimulus (local temperature), allowing the application of the ratiometric-type sensing procedure. The ability to incorporate large amounts of sacrificial singlet oxygen scavenging materials, without altering the temperature sensitivity, allows long-term protection against photo-oxidative damage to the sensing moieties. Translucent agarose/silk fibroin hydrogels embedding non-ionic micellar systems containing energetically optimized annihilation couples simultaneously fulfill two critical functions: first, to serve as mechanical support (for further application as a cell culture scaffold); second, to allow tuning of the material response window to achieve a maximum temperature sensitivity better than 0.5 K for the physiologically important region around 36 °C.
环境变化，如应用药物、营养物质消耗和代谢残留物积累，会影响细胞培养活性。这些因素的组合会反映在细胞培养支架的局部温度分布和局部氧浓度上。然而，在不考虑生物样本中局部氧浓度变化的情况下确定局部温度的时间变化，仍然是一项重大的技术挑战。在具有连续水相的纳米受限环境中进行的三重态-三重态湮灭上转换（TTA-UC）过程，似乎是解决这些严峻传感问题的一种可能方案。该过程响应单一外部刺激（局部温度）产生两个光信号（延迟发射体荧光（dF）和残余敏化剂磷光（rPh）），从而允许应用比率型传感程序。在不改变温度敏感性的情况下掺入大量牺牲性单线态氧清除材料的能力，可长期保护传感部分免受光氧化损伤。嵌入含有能量优化湮灭对的非离子胶束系统的半透明琼脂糖/丝素蛋白水凝胶同时实现两个关键功能：第一，作为机械支撑（进一步用作细胞培养支架）；第二，允许调节材料响应窗口，以在36°C左右的生理重要区域实现优于0.5 K的最大温度敏感性。
