{"title":"Thermal monitoring: Raman spectrometer system for remote measurement of cellular temperature on a microscopic scale.","authors":"Victor Pikov, Peter H Siegel","doi":"10.1109/MEMB.2009.935468","DOIUrl":null,"url":null,"abstract":"<p><p>A simple setup is demonstrated for remote temperature monitoring of water, water-based media, and cells on a microscopic scale. The technique relies on recording changes in the shape of a stretching band of the hydroxyl group in liquid water at 3,100-3,700 cm(-1). Rather than direct measurements in the near-infrared (IR), a simple Raman spectrometer setup is realized. The measured Raman shifts are observed at near optical wavelengths using an inverted microscope with standard objectives in contrast to costly near-IR elements. This allows for simultaneous visible inspection through the same optical path. An inexpensive 671-nm diode pump laser (< 100 mW), standard dichroic and lowpass filters, and a commercial 600-1,000 nm spectrometer complete the instrument. Temperature changes of 1 degrees C are readily distinguished over a range consistent with cellular processes (25-45 degrees C) using integration times below 10 s. Greatly improved sensitivity was obtained by an automated two-peak fitting procedure. When combined with an optical camera, the instrument can be used to monitor changes in cell behavior as a function of temperature without the need for invasive probing. The instrument is very simple to realize, inexpensive compared with traditional Raman spectrometers and IR microscopes, and applicable to a wide range of problems in microthermometry of biological systems. In a first application of its kind, the instrument was used to successfully determine the temperature rise of a cluster of H1299 derived human lung cells adhered to polystyrene and immersed in phosphate-buffered saline (PBS) under exposure of RF millimeter wave radiation (60 GHz, 1.3, 2.6, and 5.2 mW/mm2).</p>","PeriodicalId":50391,"journal":{"name":"IEEE Engineering in Medicine and Biology Magazine","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/MEMB.2009.935468","citationCount":"16","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Engineering in Medicine and Biology Magazine","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/MEMB.2009.935468","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 16
Abstract
A simple setup is demonstrated for remote temperature monitoring of water, water-based media, and cells on a microscopic scale. The technique relies on recording changes in the shape of a stretching band of the hydroxyl group in liquid water at 3,100-3,700 cm(-1). Rather than direct measurements in the near-infrared (IR), a simple Raman spectrometer setup is realized. The measured Raman shifts are observed at near optical wavelengths using an inverted microscope with standard objectives in contrast to costly near-IR elements. This allows for simultaneous visible inspection through the same optical path. An inexpensive 671-nm diode pump laser (< 100 mW), standard dichroic and lowpass filters, and a commercial 600-1,000 nm spectrometer complete the instrument. Temperature changes of 1 degrees C are readily distinguished over a range consistent with cellular processes (25-45 degrees C) using integration times below 10 s. Greatly improved sensitivity was obtained by an automated two-peak fitting procedure. When combined with an optical camera, the instrument can be used to monitor changes in cell behavior as a function of temperature without the need for invasive probing. The instrument is very simple to realize, inexpensive compared with traditional Raman spectrometers and IR microscopes, and applicable to a wide range of problems in microthermometry of biological systems. In a first application of its kind, the instrument was used to successfully determine the temperature rise of a cluster of H1299 derived human lung cells adhered to polystyrene and immersed in phosphate-buffered saline (PBS) under exposure of RF millimeter wave radiation (60 GHz, 1.3, 2.6, and 5.2 mW/mm2).