摘要
温度响应型纳米材料作为造影剂的巨大潜力推动了近年来光声成像领域的研究和发展,然而,目前报道的温度响应型纳米探针的响应温度超过了人体可以容忍的范围,同时可逆性低,这两个问题是其实际应用的严重障碍,影响了其有效成像和长期监测的效果。鉴于此,笔者设计了一种聚(N-异丙基丙烯酰胺)(PNIPAM)包裹金纳米棒(AuNR)的温度响应型相变纳米探针AuNR@PNIPAM,其可在生理温度附近表现出增强且可切换的近红外二区光吸收,实现对肿瘤的高对比度成像。当AuNR@PNIPAM微凝胶热靶向到肿瘤组织后,金纳米棒核吸收近红外光能量触发PNIPAM壳相变。当温度高于PNIPAM的体积相变温度时,PNIPAM水凝胶经历溶胀到坍缩的体积相变,使金纳米棒周围的折射率变大,诱导微凝胶的局域表面等离子体共振峰发生红移并使其吸收峰强度增大。体内外实验均证明,利用所制备的AuNR@PNIPAM微凝胶,在外部近红外光刺激下动态调制温度场,可以获得对比度增强的光声图像。本工作可为开发温度响应型智能光声纳米探针从而增强成像对比度提供一定的参考。
Objective The considerable potential of temperature-responsive nanomaterials as contrast agents has driven research and development in the field of photoacoustic imaging in recent years.However,the temperature-sensitive nanoprobes currently reported have response temperatures that exceed the tolerable range of humans,and their reversibility is low,which are two serious problems that hinder imaging and long-term monitoring in practical applications.Molecular photoacoustic imaging has emerged as a noninvasive imaging modality for cancer diagnosis,which couples superb optical absorption contrast and an excellent ultrasonic spatial resolution.However,research on molecular photoacoustic imaging has focused on optical wavelengths in the visible and near-infrared(NIR)part of the spectrum between 550 and 900 nm,with a relatively low sensitivity and limited imaging depth.Of note,the characteristic molecules of many major diseases—particularly in the early stage—exhibit no obvious photoacoustic contrast in the optical window of biological tissue(NIR-Ⅰ,650‒950 nm;NIR-Ⅱ,950-1700 nm).Moreover,most of the current photoacoustic contrast agents are“always-on”probes,which can only provide invariable imaging contrast and struggle to eliminate the inherent background effect of biological tissues.In contrast,activable photoacoustic contrast agents can respond to a given cancer biomarker and emit signals.Therefore,there is an urgent need to develop a stimulus-responsive photoacoustic probe for the second NIR region.In this paper,a reversible temperature-responsive phase-change AuNR@PNIPAM nanoprobe is proposed that can dynamically modulate the temperature field through an external NIR optical switch to obtain contrast-enhanced photoacoustic images.Methods When the temperature-sensitive AuNR@PNIPAM microgel is delivered to tumor tissue under 980 nm laser irradiation,the gold nanorod core absorbs NIR light energy,triggering a phase transition of the PNIPAM shell.As the temperature exceeds the volume phase transition tempe
作者
孙晓冬
石玉娇
Sun Xiaodong;Shi Yujiao(MOE Key Laboratory of Laser Life Science,College of Biophotonics,South China Normal University,Guangzhou 510631,Guangdong,China;Guangdong Provincial Key Laboratory of Laser Life Science,College of Biophotonics,South China Normal University,Guangzhou 510631,Guangdong,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2023年第21期59-69,共11页
Chinese Journal of Lasers
基金
国家自然科学基金(12174125,61805085)。
