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首页> 外文学位 >Polymer and Tissue Separation and Micro/Nano- Fabrication via Ultra-Short Pulsed Laser Plasma-Mediated Ablation.
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Polymer and Tissue Separation and Micro/Nano- Fabrication via Ultra-Short Pulsed Laser Plasma-Mediated Ablation.

机译：聚合物和组织的分离以及通过超短脉冲激光等离子体介导消融的微/纳米加工。

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摘要

Micro/nano-fabrication of polymers and micro-processing of real human tissues via plasma-mediated ablation were investigated using an ultra-short pulsed (USP) laser of 900 fs pulse duration and 1552 nm center wavelength. For the PDMS polymer micro-fabrication, the ablation threshold for the single spot and the single line scanning ablation features were studied at first. The single pulse ablation threshold is determined to be 4.62 J/cm 2 and the incubation factor for the multi-pulse ablation is found to be 0.52. The influences of pulse overlap rate and irradiation pulse energy on the ablation line width, internal ablation interface depth, and ablation surface quality were scrutinized. Then the thin layer PDMS separation was completed with thickness controllable via adjusting the laser focus spot position. For the three tests with a target thickness of 20 mum, the averaged thickness of the separated thin layers is 20.6+/- 1.7 mum. And a multi-width micro-channel interconnected network was fabricated and the size of the channels varies from 50 to 400 mum. For the real tissue ablation, the fundamental ablation features were investigated. It is found that the threshold of the single pulse ablation for the freeze-dried dermis (8.32+/-0.37 J/cm 2) is slightly smaller than that of the wet dermis (9.65+/-1.21 J/cm2) due to the light absorption of water in wet tissues. Histological examinations were performed to evaluate the thermal damage and to find appropriate laser parameters for tissue micro-processing with minimal thermal damage. An analytical solution based on the heat conduction equation was derived to analyze the temperature distributions and to obtain the heat affected zones in materials ablated by USP laser line scanning. The analytical results were compared with the experimental measurements and a good agreement was found. Both results show that the thermal damage can be confined in a small zone about 10 mum with proper pulse energy and overlap rate. Pulse energy and pulse overlap rate were the key parameters for the generation and severity of thermal damage. In vitro wet tissue separation into layers by the USP laser ablation was demonstrated with thickness ranging from 200 to 600 mum. The unevenness of the separated layers is under 10%. Freeze-dried tissue stripping was also demonstrated with the stripped thickness in the range of 20 - 40 mum. No sign of visible thermal damage was found for both types of tissues. This study has provided an effective method that can precisely and non-intrusively process polymers and tissues with minimized thermal damage.
机译：使用900 fs脉冲持续时间和1552 nm中心波长的超短脉冲（USP）激光，研究了聚合物的微/纳米加工以及通过等离子体介导的消融对人体的微处理。对于PDMS聚合物微加工，首先研究了单点和单线扫描烧蚀特征的烧蚀阈值。单脉冲消融阈值确定为4.62 J / cm 2，多脉冲消融的孵育因子为0.52。仔细研究了脉冲重叠率和辐照脉冲能量对消融线宽，内部消融界面深度和消融表面质量的影响。然后，通过调节激光焦点位置，可控制厚度的薄层PDMS分离完成。对于目标厚度为20微米的三个测试，分离的薄层的平均厚度为20.6 +/- 1.7微米。并制作了一个多宽度的微通道互连网络，通道的大小从50到400微米不等。对于真正的组织消融，研究了基本消融特征。结果发现，冻干真皮的单脉冲消融阈值（8.32 +/- 0.37 J / cm 2）略小于湿真皮的阈值（9.65 +/- 1.21 J / cm2），原因是湿组织中水的光吸收。进行组织学检查以评估热损伤，并找到合适的激光参数，以最小的热损伤对组织进行微处理。导出了基于热传导方程的解析解，以分析温度分布并获得通过USP激光线扫描烧蚀的材料中的热影响区。将分析结果与实验测量值进行了比较，发现了很好的一致性。两种结果均表明，可以通过适当的脉冲能量和重叠率将热损伤限制在约10毫米的小区域内。脉冲能量和脉冲重叠率是热损伤的产生和严重程度的关键参数。通过USP激光烧蚀证明了体外湿组织分离成层的厚度范围为200到600微米。分离层的不均匀度小于10％。还证明了冷冻干燥的组织剥离，剥离的厚度在20-40μm的范围内。两种组织都没有发现可见的热损伤迹象。这项研究提供了一种有效的方法，可以以最小的热损伤精确，非侵入性地处理聚合物和组织。

著录项

  • 作者

    Huang, Huan.;

  • 作者单位

    Rutgers The State University of New Jersey - New Brunswick.;

  • 授予单位 Rutgers The State University of New Jersey - New Brunswick.;
  • 学科 Engineering Mechanical.;Chemistry Polymer.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 211 p.
  • 总页数 211
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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