TY - JOUR
T1 - Real-time optoacoustic temperature determination on cell cultures during heat exposure
T2 - a feasibility study
AU - Miura, Yoko
AU - Seifert, Eric
AU - Rehra, Josua
AU - Kern, Katharina
AU - Theisen-Kunde, Dirk
AU - Denton, Michael
AU - Brinkmann, Ralf
PY - 2019/3/28
Y1 - 2019/3/28
N2 - Objective/Purpose: In order to study the effects of hyperthermia and other temperature-related effects on cells and tissues, determining the precise time/temperature course is crucial. Here we present a non-contact optoacoustic technique, which provides temperatures during heating of cultured cells with scalable temporal and spatial resolution. Methods: A thulium laser (1.94 µm) with a maximum power of 15 W quickly and efficiently heats cells in a culture dish because of low penetration depth (1/e penetration depths of 78 µm) of the radiation in water. A repetitively Q-switched holmium laser (2.1 µm) is used simultaneously to probe temperatures at different locations in the dish by using the photoacoustic effect. Due to thermoelastic expansion of water, pressure waves are emitted and measured with an ultrasonic hydrophone at the side of the dish. The amplitudes of the waves are temperature dependent and can be used to calculate the temperature/time course at any location of probing. Results: We measured temperatures of up to 55 °C with a heating power of 6 W after 10 s, and subsequent lateral temperature profiles over time. Within this profile, temperature fluctuations were found, likely owing to thermal convection and water circulation. By using cultured retinal pigment epithelial cells, it is shown that the probe laser pulses alone cause no biological damage, while immediate cell damage occurs when heating for 10 s at temperatures exceeding 45 °C. Conclusions: This method shows great potential not only as a noninvasive, non-contact method to determine temperature/time responses of cells in culture, but also for complex tissue and other materials.
AB - Objective/Purpose: In order to study the effects of hyperthermia and other temperature-related effects on cells and tissues, determining the precise time/temperature course is crucial. Here we present a non-contact optoacoustic technique, which provides temperatures during heating of cultured cells with scalable temporal and spatial resolution. Methods: A thulium laser (1.94 µm) with a maximum power of 15 W quickly and efficiently heats cells in a culture dish because of low penetration depth (1/e penetration depths of 78 µm) of the radiation in water. A repetitively Q-switched holmium laser (2.1 µm) is used simultaneously to probe temperatures at different locations in the dish by using the photoacoustic effect. Due to thermoelastic expansion of water, pressure waves are emitted and measured with an ultrasonic hydrophone at the side of the dish. The amplitudes of the waves are temperature dependent and can be used to calculate the temperature/time course at any location of probing. Results: We measured temperatures of up to 55 °C with a heating power of 6 W after 10 s, and subsequent lateral temperature profiles over time. Within this profile, temperature fluctuations were found, likely owing to thermal convection and water circulation. By using cultured retinal pigment epithelial cells, it is shown that the probe laser pulses alone cause no biological damage, while immediate cell damage occurs when heating for 10 s at temperatures exceeding 45 °C. Conclusions: This method shows great potential not only as a noninvasive, non-contact method to determine temperature/time responses of cells in culture, but also for complex tissue and other materials.
UR - http://www.scopus.com/inward/record.url?scp=85063572726&partnerID=8YFLogxK
U2 - 10.1080/02656736.2019.1590653
DO - 10.1080/02656736.2019.1590653
M3 - Journal articles
C2 - 30922131
AN - SCOPUS:85063572726
SN - 0265-6736
VL - 36
SP - 466
EP - 472
JO - International Journal of Hyperthermia
JF - International Journal of Hyperthermia
IS - 1
ER -