Multiscale Photoacoustic Microscopy of Single-Walled Carbon Nanotube-Incorporated Tissue Engineering Scaffolds
Multiscale Photoacoustic Microscopy of Single-Walled Carbon Nanotube-Incorporated Tissue Engineering Scaffolds
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DOI：
10.1089/ten.tec.2011.0519
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发表时间：
2012-04-01
影响因子：
3
通讯作者：
Wang, Lihong V.
中科院分区：
文献类型：
--
作者：
Cai, Xin;Paratala, Bhavna S.;Wang, Lihong V.
三维聚合物支架为组织再生所必需的细胞和生物活性分子提供结构支持和基底功能。支架和/或支架内组织形成过程的无创实时成像仍然是一个挑战。微计算机断层扫描，广泛用于表征聚合物支架的技术，显示浸泡在生物流体中的支架对比度较差，从而限制了其在生理条件下的应用。本文采用多尺度光声显微镜（PAM），包括声分辨率PAM （AR-PAM）和光学分辨率PAM (OR-PAM)，对浸在生物缓冲液中的单壁碳纳米管（SWNT）掺入聚乳酸-羟基乙酸聚合物支架进行了成像和表征。加入单壁碳纳米管增强了支架的力学性能，增强了支架的光声信号。通过选择激发波长为570和638 nm，多尺度PAM可以光谱区分血液和碳纳米管支架产生的光声信号。OR-PAM的横向分辨率为2.6 μ m，组织渗透率为660 μ m，成功地量化了支架的平均孔隙率和孔径分别为86.5%+/- 1.2%和153 +/- 15 μ m。AR-PAM进一步将组织穿透深度扩展到2mm，但牺牲了横向分辨率（45 μ m）。我们的研究结果表明，PAM是一种很有前途的工具，可以在体外和生理条件下对组织工程支架进行无创实时成像和监测。
Three-dimensional polymeric scaffolds provide structural support and function as substrates for cells and bioactive molecules necessary for tissue regeneration. Noninvasive real-time imaging of scaffolds and/or the process of tissue formation within the scaffold remains a challenge. Microcomputed tomography, the widely used technique to characterize polymeric scaffolds, shows poor contrast for scaffolds immersed in biological fluids, thereby limiting its utilities under physiological conditions. In this article, multiscale photoacoustic microscopy (PAM), consisting of both acoustic-resolution PAM (AR-PAM) and optical-resolution PAM (OR-PAM), was employed to image and characterize single-walled carbon-nanotube (SWNT)-incorporated poly(lactic-co-glycolic acid) polymer scaffolds immersed in biological buffer. SWNTs were incorporated to reinforce the mechanical properties of the scaffolds, and to enhance the photoacoustic signal from the scaffolds. By choosing excitation wavelengths of 570 and 638 nm, multiscale PAM could spectroscopically differentiate the photoacoustic signals generated from blood and from carbon-nanotube-incorporated scaffolds. OR-PAM, providing a fine lateral resolution of 2.6 mu m with an adequate tissue penetration of 660 mu m, successfully quantified the average porosity and pore size of the scaffolds to be 86.5%+/- 1.2% and 153 +/- 15 mu m in diameter, respectively. AR-PAM further extended the tissue penetration to 2mm at the expense of lateral resolution (45 mu m). Our results suggest that PAM is a promising tool for noninvasive real-time imaging and monitoring of tissue engineering scaffolds in vitro, and in vivo under physiological conditions.