Ultrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopy

Abstract In vivo IR spectroscopy faces challenges due to poor sensitivity in reflection mode and low resolution at micrometer scale. To break this barrier, we report an oblique photothermal microscope (OPTM) to enable ultrasensitive IR spectroscopic imaging of live subjects at sub-micron resolution....

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Main Authors: Mingsheng Li, Sheng Xiao, Hongli Ni, Guangrui Ding, Yuhao Yuan, Carolyn Marar, Jerome Mertz, Ji-Xin Cheng
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-61332-w
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author Mingsheng Li
Sheng Xiao
Hongli Ni
Guangrui Ding
Yuhao Yuan
Carolyn Marar
Jerome Mertz
Ji-Xin Cheng
author_facet Mingsheng Li
Sheng Xiao
Hongli Ni
Guangrui Ding
Yuhao Yuan
Carolyn Marar
Jerome Mertz
Ji-Xin Cheng
author_sort Mingsheng Li
collection DOAJ
description Abstract In vivo IR spectroscopy faces challenges due to poor sensitivity in reflection mode and low resolution at micrometer scale. To break this barrier, we report an oblique photothermal microscope (OPTM) to enable ultrasensitive IR spectroscopic imaging of live subjects at sub-micron resolution. Classic photothermal measurement captures only a small fraction of probe photons through an iris to extract the photothermal signal. Instead, OPTM uses a differential split detector placed on the sample surface to collect 500-fold more photons and suppress the laser noise by 12 fold via balanced detection. Leveraging its improved sensitivity, OPTM enables low-dose IR imaging of skin without photodamage. Depth-resolved in vivo OPTM imaging of metabolic markers beneath mouse and human skin is shown. Furthermore, we demonstrate in vivo OPTM tracking of topical drug contents within mouse and human skin. Collectively, OPTM presents a highly sensitive imaging platform for in vivo and in situ molecular analysis.
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institution Kabale University
issn 2041-1723
language English
publishDate 2025-07-01
publisher Nature Portfolio
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series Nature Communications
spelling doaj-art-4eaa868199724d7292c1510cc3d3d8072025-08-20T03:37:38ZengNature PortfolioNature Communications2041-17232025-07-0116111510.1038/s41467-025-61332-wUltrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopyMingsheng Li0Sheng Xiao1Hongli Ni2Guangrui Ding3Yuhao Yuan4Carolyn Marar5Jerome Mertz6Ji-Xin Cheng7Department of Electrical and Computer Engineering, Boston UniversityDepartment of Electrical and Computer Engineering, Boston UniversityDepartment of Electrical and Computer Engineering, Boston UniversityDepartment of Electrical and Computer Engineering, Boston UniversityDepartment of Electrical and Computer Engineering, Boston UniversityPhotonics Center, Boston UniversityPhotonics Center, Boston UniversityDepartment of Electrical and Computer Engineering, Boston UniversityAbstract In vivo IR spectroscopy faces challenges due to poor sensitivity in reflection mode and low resolution at micrometer scale. To break this barrier, we report an oblique photothermal microscope (OPTM) to enable ultrasensitive IR spectroscopic imaging of live subjects at sub-micron resolution. Classic photothermal measurement captures only a small fraction of probe photons through an iris to extract the photothermal signal. Instead, OPTM uses a differential split detector placed on the sample surface to collect 500-fold more photons and suppress the laser noise by 12 fold via balanced detection. Leveraging its improved sensitivity, OPTM enables low-dose IR imaging of skin without photodamage. Depth-resolved in vivo OPTM imaging of metabolic markers beneath mouse and human skin is shown. Furthermore, we demonstrate in vivo OPTM tracking of topical drug contents within mouse and human skin. Collectively, OPTM presents a highly sensitive imaging platform for in vivo and in situ molecular analysis.https://doi.org/10.1038/s41467-025-61332-w
spellingShingle Mingsheng Li
Sheng Xiao
Hongli Ni
Guangrui Ding
Yuhao Yuan
Carolyn Marar
Jerome Mertz
Ji-Xin Cheng
Ultrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopy
Nature Communications
title Ultrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopy
title_full Ultrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopy
title_fullStr Ultrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopy
title_full_unstemmed Ultrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopy
title_short Ultrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopy
title_sort ultrasensitive in vivo infrared spectroscopic imaging via oblique photothermal microscopy
url https://doi.org/10.1038/s41467-025-61332-w
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AT yuhaoyuan ultrasensitiveinvivoinfraredspectroscopicimagingviaobliquephotothermalmicroscopy
AT carolynmarar ultrasensitiveinvivoinfraredspectroscopicimagingviaobliquephotothermalmicroscopy
AT jeromemertz ultrasensitiveinvivoinfraredspectroscopicimagingviaobliquephotothermalmicroscopy
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