Saitta Lorena, Cutuli Emanuela, Celano Giovanni, Tosto Claudio, Sanalitro Dario, Guarino Francesca, Cicala Gianluca, Bucolo Maide
Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Department of Electrical Electronic and Computer Science Engineering, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Polymers (Basel). 2023 Nov 19;15(22):4461. doi: 10.3390/polym15224461.
In this work, a 3D printed biocompatible micro-optofluidic (MoF) device for two-phase flow monitoring is presented. Both an air-water bi-phase flow and a two-phase mixture composed of micrometric cells suspended on a liquid solution were successfully controlled and monitored through its use. To manufacture the MoF device, a highly innovative microprecision 3D printing technique was used named Projection Microstereolithography (PμSL) in combination with the use of a novel 3D printable photocurable resin suitable for biological and biomedical applications. The concentration monitoring of biological fluids relies on the absorption phenomenon. More precisely, the nature of the transmission of the light strictly depends on the cell concentration: the higher the cell concentration, the lower the optical acquired signal. To achieve this, the microfluidic T-junction device was designed with two micrometric slots for the optical fibers' insertion, needed to acquire the light signal. In fact, both the micro-optical and the microfluidic components were integrated within the developed device. To assess the suitability of the selected biocompatible transparent resin for optical detection relying on the selected working principle (absorption phenomenon), a comparison between a two-phase flow process detected inside a previously fully characterized micro-optofluidic device made of a nonbiocompatible high-performance resin (HTL resin) and the same made of the biocompatible one (BIO resin) was carried out. In this way, it was possible to highlight the main differences between the two different resin grades, which were further justified with proper chemical analysis of the used resins and their hydrophilic/hydrophobic nature via static water contact angle measurements. A wide experimental campaign was performed for the biocompatible device manufactured through the PμSL technique in different operative conditions, i.e., different concentrations of eukaryotic yeast cells of (with a diameter of 5 μm) suspended on a PBS (phosphate-buffered saline) solution. The performed analyses revealed that the selected photocurable transparent biocompatible resin for the manufactured device can be used for cell concentration monitoring by using ad hoc 3D printed micro-optofluidic devices. In fact, by means of an optical detection system and using the optimized operating conditions, i.e., the optimal values of the flow rate FR=0.1 mL/min and laser input power P∈{1,3} mW, we were able to discriminate between biological fluids with different concentrations of suspended cells with a robust working ability R2=0.9874 and Radj2=0.9811.
在这项工作中，提出了一种用于两相流监测的3D打印生物相容性微流控光学（MoF）装置。通过使用该装置，成功地控制和监测了空气-水双相流以及由悬浮在液体溶液中的微米级细胞组成的两相混合物。为了制造MoF装置，使用了一种名为投影微立体光刻（PμSL）的高度创新的微精密3D打印技术，并结合使用了一种适用于生物和生物医学应用的新型3D可打印光固化树脂。生物流体的浓度监测依赖于吸收现象。更确切地说，光的传输特性严格取决于细胞浓度：细胞浓度越高，采集到的光信号越低。为实现这一点，微流控T型结装置设计有两个用于插入光纤的微米级狭槽，用于采集光信号。实际上，微光学和微流体组件都集成在开发的装置中。为了根据选定的工作原理（吸收现象）评估所选生物相容性透明树脂用于光学检测的适用性，对在先前完全表征的由非生物相容性高性能树脂（HTL树脂）制成的微流控光学装置内检测到的两相流过程与由生物相容性树脂（BIO树脂）制成的相同装置进行了比较。通过这种方式，突出了两种不同树脂等级之间的主要差异，并通过对所用树脂及其亲水/疏水性质进行适当的化学分析以及静态水接触角测量进一步证明了这些差异。针对通过PμSL技术制造的生物相容性装置，在不同的操作条件下，即悬浮在磷酸盐缓冲盐水（PBS）溶液中的不同浓度的真核酵母细胞（直径为5μm），开展了广泛的实验研究。所进行的分析表明，为制造的装置所选的光固化透明生物相容性树脂可通过使用专门设计的3D打印微流控光学装置用于细胞浓度监测。事实上，借助光学检测系统并使用优化的操作条件，即流速FR = 0.1 mL/min和激光输入功率P∈{1,3} mW的最佳值，我们能够以稳健的工作能力R2 = 0.9874和Radj2 = 0.9811区分具有不同悬浮细胞浓度的生物流体。
