Photoacoustic Doppler flow measurement based on continuous wave laser excitation owns the merit of clearly presenting the Doppler power spectra.Extending this technique to dual wavelengths can gain the spectral inform...Photoacoustic Doppler flow measurement based on continuous wave laser excitation owns the merit of clearly presenting the Doppler power spectra.Extending this technique to dual wavelengths can gain the spectral information of the flow sample extra to the flow speed information.An experimental system with two laser diodes respectively operated at 405 nm and 660 nm wavelengths is built and the flow measurement with black and red dyed polystyrene beads is performed.The measured Doppler power spectra can vividly reflect the flow speed,the flow direction,as well as the bead color.Since it is straightforward to further apply the same principle to multiple wavelengths,we can expect this type of spectroscopic photoacoustic Doppler flow measurement will be developed in the near future which will be very useful for studying the metabolism of the slowly moving red blood cell inside microvessels.展开更多
A photoacoustic （PA） spectrometer with H-type first longitudinal resonant cells for ammonia detection is developed. A new PA cell structure is designed to accelerate the drift velocity of the sample gas near the cel...A photoacoustic （PA） spectrometer with H-type first longitudinal resonant cells for ammonia detection is developed. A new PA cell structure is designed to accelerate the drift velocity of the sample gas near the cell surface, so that the short response time at the flow rate of 100 seem （standard cubic centimeter per minute） is achieved. The response time of 5 min and detection limit of 0.86 ppbv is reached for ammonia concentration measurement with a Teflon polytetrafluoroethylene （PTFE） cell. Further improvement could be expected when using a brass cell with a high quality Teflon fluorinated ethylene propylene （FEP） coating.展开更多
The previous methods to measure flow speed by photoacoustic microscopy solely focused on either the transverse or the axial flow component, which did not reflect absolute flow speed. Here, we present absolute flow spe...The previous methods to measure flow speed by photoacoustic microscopy solely focused on either the transverse or the axial flow component, which did not reflect absolute flow speed. Here, we present absolute flow speed maps by combining Doppler bandwidth broadening with volumetric photoacoustic microscopy. Photoacoustic Doppler bandwidth broadening and photoacoustic tomographic images were applied to measure the transverse flow component and the Doppler angle, respectively. Phantom experiments quantitatively demonstrated that ranges of 55° to 90° Doppler angle and 0.5 to 10 mm/s flow speed can be measured. This tomography-assisted method provides the foundation for further measurement in vivo.展开更多
Blood analysis is a ubiquitous and critical aspect of modern medicine.Analyzing blood samples requires invasive techniques,various testing systems,and samples are limited to relatively small volumes.Photoacoustic imag...Blood analysis is a ubiquitous and critical aspect of modern medicine.Analyzing blood samples requires invasive techniques,various testing systems,and samples are limited to relatively small volumes.Photoacoustic imaging(PAI)is a novel imaging modality that utilizes non-ionizing energy that shows promise as an alternative to current methods.This paper seeks to review current applications of PAI in blood analysis for clinical use.Furthermore,we discuss obstacles to implementation and future directions to overcome these challenges.Firstly,we discuss three applications to cellular analysis of blood:sickle cell,bacteria,and circulating tumor cell detection.We then discuss applications to the analysis of blood plasma,including glucose detection and anticoagulation quantification.As such,we hope this article will serve as inspiration for PAI's potential application in blood analysis and prompt further studies to ultimately implement PAI into clinical practice.展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant No.11774256)the Natural Science Foundation of Guangdong Province(Grant No.2018B03031104).
文摘Photoacoustic Doppler flow measurement based on continuous wave laser excitation owns the merit of clearly presenting the Doppler power spectra.Extending this technique to dual wavelengths can gain the spectral information of the flow sample extra to the flow speed information.An experimental system with two laser diodes respectively operated at 405 nm and 660 nm wavelengths is built and the flow measurement with black and red dyed polystyrene beads is performed.The measured Doppler power spectra can vividly reflect the flow speed,the flow direction,as well as the bead color.Since it is straightforward to further apply the same principle to multiple wavelengths,we can expect this type of spectroscopic photoacoustic Doppler flow measurement will be developed in the near future which will be very useful for studying the metabolism of the slowly moving red blood cell inside microvessels.
基金This work was supported by the National Natural Science Foundation of China under Grant No.60677010.
文摘A photoacoustic （PA） spectrometer with H-type first longitudinal resonant cells for ammonia detection is developed. A new PA cell structure is designed to accelerate the drift velocity of the sample gas near the cell surface, so that the short response time at the flow rate of 100 seem （standard cubic centimeter per minute） is achieved. The response time of 5 min and detection limit of 0.86 ppbv is reached for ammonia concentration measurement with a Teflon polytetrafluoroethylene （PTFE） cell. Further improvement could be expected when using a brass cell with a high quality Teflon fluorinated ethylene propylene （FEP） coating.
基金supported by the National Natural Science Foundation of China (Nos. 61822505,11774101,61627827,and 81630046)the Science and Technology Planning Project of Guangdong Province,China(No. 2015B020233016)+2 种基金the China Postdoctoral Science Foundation (No. 2019M652943)the Natural Science Foundation of Guangdong Province,China(No. 2019A1515011399)the Science and Technology Program of Guangzhou (No. 2019050001)
文摘The previous methods to measure flow speed by photoacoustic microscopy solely focused on either the transverse or the axial flow component, which did not reflect absolute flow speed. Here, we present absolute flow speed maps by combining Doppler bandwidth broadening with volumetric photoacoustic microscopy. Photoacoustic Doppler bandwidth broadening and photoacoustic tomographic images were applied to measure the transverse flow component and the Doppler angle, respectively. Phantom experiments quantitatively demonstrated that ranges of 55° to 90° Doppler angle and 0.5 to 10 mm/s flow speed can be measured. This tomography-assisted method provides the foundation for further measurement in vivo.
基金This research was funded by The United States National Institutes of Health(NIH)grants R38HL143612,R21EB027981,R21 EB027304,RF1 NS115581(BRAIN Initiative),R01 NS111039,R01 EB028143The United States National Science Foundation(NSF)CAREER award 2144788Chan Zuckerberg Initiative Grant(2020-226178).
文摘Blood analysis is a ubiquitous and critical aspect of modern medicine.Analyzing blood samples requires invasive techniques,various testing systems,and samples are limited to relatively small volumes.Photoacoustic imaging(PAI)is a novel imaging modality that utilizes non-ionizing energy that shows promise as an alternative to current methods.This paper seeks to review current applications of PAI in blood analysis for clinical use.Furthermore,we discuss obstacles to implementation and future directions to overcome these challenges.Firstly,we discuss three applications to cellular analysis of blood:sickle cell,bacteria,and circulating tumor cell detection.We then discuss applications to the analysis of blood plasma,including glucose detection and anticoagulation quantification.As such,we hope this article will serve as inspiration for PAI's potential application in blood analysis and prompt further studies to ultimately implement PAI into clinical practice.
