小鼠膀胱内金属纳米粒子的光热光学相干层析成像

Metal Nanoparticle Reagents Image in Mouse Bladder With Photothermal Optical Coherence Tomography

本文提出了一种利用光热相差对金属纳米粒子(NP)试剂进行光学相干层析成像(OCT)的方法.通过记录光热相位,可以跟踪深度可分辨、实时和高度局部化的光热转换.对于绝热吸收,光热相差代表了NP的局部光吸收特性.为了验证该方法的有效性,我们首先利用FD-OCT成像系统对不同浓度的NP试剂进行了琼脂体模实验.结果表明,光热相位差可以用来区分琼脂体模中不同浓度的NP试剂.随后,一只体重约为25 g的3月龄雄性C57BL/6J小鼠被用来验证在组织中重建NP试剂分布方法的可行性.实验前先使用0.12 ml浓度为0.15 g/ml的水合氯醛麻醉,然后通过插入尿道的套管针将100 ml浓度为60μg/L的NP试剂注入小鼠膀胱内.大约4 h后,用小鼠膀胱重建光热图像.通过分析小鼠膀胱的OCT结构图像,可以清晰地观察到两个可分辨的层.第一层为逼尿肌,第二层为黏膜肌层.总之,我们从理论和实验证明了利用光热相差可以重建NP试剂在组织中的分布.由于热膨胀和热折射率效应,光热相差会引起组织局部温度的变化.对于绝热吸收,光热相差与NP试剂的浓度有关.因此,该方法可用于区分模型中不同浓度的NP试剂,并重建NP试剂在小鼠膀胱中的分布.

The paper presents a method to use the photothermal phase difference to map metal nanoparticle(NP)reagent with optical coherence tomography(OCT).The depth-resolved,real-time,and highly localized light-to-heat conversion can be traced by recording the photothermal phase.For adiabatic absorption,the photothermal phase difference represents the localized light absorption characteristics of the NPs.In order to prove the effectiveness of our method,we firstly used FD-OCT imaging system to do agar phantom experiments with different concentrations of NP reagent.The results show that the photothermal phase difference can be used to distinguish different concentrations of NP reagent in agar model.Subsequently,a 3-month-old male C57BL/6J mouse weighing about 25 g was used to verify the feasibility of our method for reconstructing the distribution of NP reagent in tissues.Before the experiment,0.12 ml chloral hydrate with a concentration of 0.15 g/ml was used for anesthesia,and then 100 ml NP solution with a concentration of 60μg/L was injected into the bladder of mice through a trocar inserted into the urethra.After about 4 hours,the mouse bladder was used to reconstruct the photothermal image.By analyzing the OCT structural image of mouse bladder,we can clearly observe two distinguishable layers.The first layer is detrusor and the second layer is muscularis mucosa.The results are consistent with those reported.In conclusion,we have proved theoretically and experimentally that the distribution of NP reagent in tissues can be reconstructed by photothermal phase difference.Owing to thermal expansion and thermal refractive index effect,the photothermal phase difference can produce local temperature changes in the tissue.For adiabatic absorption,the photothermal phase difference is related to the concentration of NPs.Therefore,it has been used to distinguish different concentrations of NP in the model and reconstruct the distribution of NP in the bladder of mice.