Azim Nilab, Orrico Julia Freitas, Appavoo Divambal, Zhai Lei, Rajaraman Swaminathan
NanoScience Technology Center (NSTC), University of Central Florida Orlando FL 32826 USA
Department of Chemistry, University of Central Florida Orlando FL 32826 USA.
RSC Adv. 2022 Sep 22;12(39):25605-25616. doi: 10.1039/d2ra03911g. eCollection 2022 Sep 5.
3D printing involves the use of photopolymerizable resins, which are toxic and typically have incompatible properties with materials such as polystyrene (PS), which present limitations for biomedical applications. We present a method to dramatically improve the poor adhesion between the PS insulative layer on 3D printed Microelectrode Array (MEA) substrates by functionalizing the resin surface with polydopamine (PDA), a mussel-inspired surface chemistry derivative. A commercial 3D printing prepolymer resin, FormLabs Clear (FLC), was printed using a digital light processing (DLP) printer and then surface functionalized with PDA by alkali-induced aqueous immersion deposition and self-polymerization. It was observed that the adhesion of the PS to FLC was improved due to the precision emanating from the DLP method and further improved after the functionalization of DLP printed substrates with PDA at 1, 12, and 24 h time intervals. The adhesion of PS was evaluated through scotch tape peel testing and instron measurements of planar substrates and incubation testing with qualitative analysis of printed culture wells. The composition and topology of the samples were studied to understand how the properties of the surface change after PDA functionalization and how this contributes to the overall improvement in PS adhesion. Furthermore, the surface energies at each PDA deposition time were calculated from contact angle studies as it related to adhesion. Finally, biocompatibility assays of the newly modified surfaces were performed using mouse cardiac cells (HL-1) to demonstrate the biocompatibility of the PDA functionalization process. PDA surface functionalization of 3D DLP printed FLC resin resulted in a dramatic improvement of thin film PS adhesion and proved to be a biocompatible solution for improving additive manufacturing processes to realize biosensors such as MEAs.
3D打印涉及使用可光聚合树脂，这些树脂有毒，并且通常与聚苯乙烯（PS）等材料具有不相容的特性，这给生物医学应用带来了限制。我们提出了一种方法，通过用聚多巴胺（PDA）对树脂表面进行功能化处理来显著改善3D打印微电极阵列（MEA）基板上PS绝缘层之间较差的附着力，聚多巴胺是一种受贻贝启发的表面化学衍生物。使用数字光处理（DLP）打印机打印商用3D打印预聚物树脂FormLabs Clear（FLC），然后通过碱诱导的水浸沉积和自聚合用PDA对其表面进行功能化处理。观察到，由于DLP方法的精确性，PS与FLC的附着力得到了改善，并且在用PDA以1小时、12小时和24小时的时间间隔对DLP打印基板进行功能化处理后，附着力进一步提高。通过胶带剥离测试、平面基板的英斯特朗测量以及对打印培养孔的定性分析孵育测试来评估PS的附着力。研究了样品的组成和拓扑结构，以了解PDA功能化处理后表面性质如何变化以及这如何有助于PS附着力的整体改善。此外，根据与附着力相关的接触角研究计算了每个PDA沉积时间的表面能。最后，使用小鼠心脏细胞（HL-1）对新修饰的表面进行生物相容性测定，以证明PDA功能化过程的生物相容性。3D DLP打印的FLC树脂的PDA表面功能化显著改善了薄膜PS的附着力，并被证明是一种生物相容性解决方案，可用于改进增材制造工艺以实现诸如MEA的生物传感器。
