INESC TEC-INESC Technology and Science, 4200-465 Porto, Portugal.
Physics and Astronomy Department, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal.
Sensors (Basel). 2018 Aug 21;18(9):2746. doi: 10.3390/s18092746.
Optical fiber tweezers have been gaining prominence in several applications in Biology and Medicine. Due to their outstanding focusing abilities, they are able to trap and manipulate microparticles, including cells, needing any physical contact and with a low degree of invasiveness to the trapped cell. Recently, we proposed a fiber tweezer configuration based on a polymeric micro-lens on the top of a single mode fiber, obtained by a self-guided photopolymerization process. This configuration is able to both trap and identify the target through the analysis of short-term portions of the back-scattered signal. In this paper, we propose a variant of this fabrication method, capable of producing more robust fiber tips, which produce stronger trapping effects on targets by as much as two to ten fold. These novel lenses maintain the capability of distinguish the different classes of trapped particles based on the back-scattered signal. This novel fabrication method consists in the introduction of a multi mode fiber section on the tip of a single mode (SM) fiber. A detailed description of how relevant fabrication parameters such as the length of the multi mode section and the photopolymerization laser power can be tuned for different purposes (e.g., microparticles trapping only, simultaneous trapping and sensing) is also provided, based on both experimental and theoretical evidences.
光纤镊子在生物学和医学的多个应用中越来越受到关注。由于其出色的聚焦能力，它们能够捕获和操纵微粒子，包括细胞，而无需任何物理接触，对被捕获的细胞的侵入性也很低。最近，我们提出了一种基于在单模光纤顶部的聚合物微透镜的光纤镊子配置，通过自导光聚合过程获得。这种配置不仅能够通过分析背向散射信号的短期部分来捕获和识别目标，还能够通过分析背向散射信号的短期部分来捕获和识别目标。在本文中，我们提出了这种制造方法的一种变体，能够制造出更坚固的光纤尖端，从而使目标的捕获效果增强 2 到 10 倍。这些新型透镜能够根据背向散射信号区分不同类型的被捕获的粒子。这种新的制造方法包括在单模 (SM) 光纤的尖端引入一段多模光纤。还根据实验和理论证据，详细描述了如何调整相关制造参数（例如多模部分的长度和光聚合激光功率），以适应不同的目的（例如，仅捕获微粒子、同时捕获和感测）。
