A Non-Cytotoxic Resin for Micro-Stereolithography for Cell Cultures of HUVECs

Abstract

Three-dimensional (3D) printing of microfluidic devices continuously replaces conventional fabrication methods. A versatile tool for achieving microscopic feature sizes and short process times is micro-stereolithography (µSL). However, common resins for µSL lack biocompatibility and are cytotoxic. This work focuses on developing new photo-curable resins as a basis for µSL fabrication of polymer materials and surfaces for cell culture. Different acrylate- and methacrylate-based compositions are screened for material characteristics including wettability, surface roughness, and swelling behavior. For further understanding, the impact of photo-absorber and photo-initiator on the cytotoxicity of 3D-printed substrates is studied. Cell culture experiments with human umbilical vein endothelial cells (HUVECs) in standard polystyrene vessels are compared to 3D-printed parts made from our library of homemade resins. Among these, after optimizing material composition and post-processing, we identify selected mixtures of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) methyl ethyl methacrylate (PEGMEMA) as most suitable to allow for fabricating cell culture platforms that retain both the viability and proliferation of HUVECs. Next, our PEGDA/PEGMEMA resins will be further optimized regarding minimal feature size and cell adhesion to fabricate microscopic (microfluidic) cell culture platforms, e.g., for studying vascularization of HUVECs in vitro.

Fabrication of Microfluidic Devices for Emulsion Formation by Microstereolithography

“…Because 3D-printed materials in PµSL often exhibit substantial toxicity due to additives, such as the UV-absorber Sudan I, they are not suitable for most biomedical applications. To address this problem, Männel et al [ 148 ] and Warr et al [ 149 ] developed resins that were based on poly(ethylene glycol) diacrylate (PEGDA) exhibiting sufficient cell viability and proliferation in long-term cell culture experiments. Männel et al [ 148 ] proposed a combination of PEGDA, poly(ethylene glycol) methyl ethyl methacrylate, Sudan 1, and diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide to cultivate human umbilical vein endothelial cells for 24 days.…”

“…To address this problem, Männel et al [ 148 ] and Warr et al [ 149 ] developed resins that were based on poly(ethylene glycol) diacrylate (PEGDA) exhibiting sufficient cell viability and proliferation in long-term cell culture experiments. Männel et al [ 148 ] proposed a combination of PEGDA, poly(ethylene glycol) methyl ethyl methacrylate, Sudan 1, and diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide to cultivate human umbilical vein endothelial cells for 24 days. Washing the 3D-printed object after the printing process in phosphate-buffered saline removed Sudan 1, dramatically reducing the cytotoxicity of the 3D-printed cell culturing substrates.…”

Resins for Frontal Photopolymerization: Combining Depth-Cure and Tunable Mechanical Properties

“…Contrary to the earlier reputation of low mechanical properties (high brittleness), high-performance photopolymers with exceptional characteristics are now produced [ 3 , 4 , 5 , 6 ]. In addition, advanced 3D printing technologies, such as stereolithography (SLA) or hot lithography and two-photon polymerization, realize highly complex geometries and ultra-smooth surfaces layer by layer [ 7 , 8 ]. Nevertheless, the maximum curing depth in photopolymerization is limited by the attenuation of light according to Beer–Lambert’s law.…”

Materials Testing for the Development of Biocompatible Devices through Vat-Polymerization 3D Printing

“…Hence, there is a growing interest in recent times for the development of biocompatible (meth)acrylate resins for light-based 3D printing applications [ 27 , 28 ]. Regarding biocompatible acrylate-based 3D printed devices, it has recently been reported the preparation of formulations using acrylate monomers for the 3D printing of objects for Human Umbilical Vein Endothelial Cells (HUVECs) culturing with moderate viability [ 29 ]. Urrios et al used a low-molecular PEG-based acrylate monomer for the production of 3D printed transparent bio-microfluidics devices and Petri-dish platforms used for mammalian cells and hippocampal neurons culture [ 30 ].…”