Heinrich Ernesta, Avlasevich Yuri, Landfester Katharina, Baluschev Stanislav
Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Sofia University "St. Kliment Ochridski", 5 James Bourchier Blvd, 1164 Sofia, Bulgaria.
ACS Omega. 2021 Jul 16;6(29):18860-18867. doi: 10.1021/acsomega.1c02057. eCollection 2021 Jul 27.
Penetration and emanation of light into tissue are limited by the strong interaction of light with the tissue components, especially oxygenated hemoglobin and white adipose tissue. This limits the possibilities for all-optical minimal invasive sensing. In order to minimize the optical losses of light in and out of the tissue, only a narrow optical window between 630 and 900 nm is available. In this work, we realized for the first time all-optical temperature sensing within the narrow optical window for tissue by using the process of triplet-triplet annihilation photon energy upconversion (TTA-UC) as a sensing tool. For this, we apply the asymmetrical benzo-fused BODIPY dye as an optimal emitter and mixed palladium benzo-naphtho-porphyrins as an optimal sensitizer. The TTA-UC sensing system is excited with λ = 658 nm with an extremely low intensity of 1 mW × cm and is factual-protected for a time period longer than 100 s against oxygen-stimulated damage, allowing a stable demonstration of this T-sensing system also in an oxygen-rich environment without losing sensitivity. The sensing dyes we embed in the natural wax/natural matrix, which is intrinsically biocompatible, are approved by the FDA as food additives. The demonstrated temperature sensitivity is higher than Δ = 200 mK placed around the physiologically relevant temperature of = 36 °C.
光进入组织的穿透和发射受到光与组织成分，特别是氧合血红蛋白和白色脂肪组织之间强烈相互作用的限制。这限制了全光学微创传感的可能性。为了使光在组织内外的光学损失最小化，只有630至900纳米之间的一个狭窄光学窗口可用。在这项工作中，我们首次通过使用三重态-三重态湮灭光子能量上转换（TTA-UC）过程作为传感工具，在组织的狭窄光学窗口内实现了全光学温度传感。为此，我们应用不对称苯并稠合硼二吡咯染料作为最佳发射体，并将混合钯苯并萘卟啉作为最佳敏化剂。TTA-UC传感系统用波长λ = 658纳米、强度极低为1毫瓦×平方厘米的光激发，并且在超过100秒的时间段内实际受到保护，免受氧刺激损伤，从而能够在富氧环境中稳定展示这种温度传感系统而不丧失灵敏度。我们嵌入天然蜡/天然基质中的传感染料本质上具有生物相容性，已被美国食品药品监督管理局批准为食品添加剂。所展示的温度灵敏度高于在生理相关温度约36°C附近的200毫开尔文。
