Feasibility and Biocompatibility of 3D‐Printed Photopolymerized and Laser Sintered Polymers for Neuronal, Myogenic, and Hepatic Cell Types

Abstract

The integration of additive manufacturing (AM) technology within biological systems holds significant potential, specifically when refining the methods utilized for the creation of in vitro models. Therefore, examination of cellular interaction with the physical/physicochemical properties of 3D-printed polymers is critically important. In this work, skeletal muscle (C C ), neuronal (SH-SY5Y) and hepatic (HepG2) cell lines are utilized to ascertain critical evidence of cellular behavior in response to 3D-printed candidate polymers: Clear-FL (stereolithography, SL), PA-12 (laser sintering, LS), and VeroClear (PolyJet). This research outlines initial critical evidence for a framework of polymer/AM process selection when 3D printing biologically receptive scaffolds, derived from industry standard, commercially available AM instrumentation. C C , SH-SY5Y, and HepG2 cells favor LS polymer PA-12 for applications in which cellular adherence is necessitated. However, cell type specific responses are evident when cultured in the chemical leachate of photopolymers (Clear-FL and VeroClear). With the increasing prevalence of 3D-printed biointerfaces, the development of rigorous cell type specific biocompatibility data is imperative. Supplementing the currently limited database of functional 3D-printed biomaterials affords the opportunity for experiment-specific AM process and polymer selection, dependent on biological application and intricacy of design features required.

3D Printing of Cell Culture Devices: Assessment and Prevention of the Cytotoxicity of Photopolymers for Stereolithography

“…The High Temp resin was also found to be toxic in a previous study performed with HeLa cells [ 23 ]. Incubation with Clear or “Clear-conditioned” media was found to reduce proliferation across several species and several human tumor cell lines (SH-SY5Y, HepG2, HeLa, L929) [ 17 , 23 , 24 , 25 ]. However, dependent on cell type and postprocessing, the toxicity was not as pronounced as in our study [ 25 ].…”

“…However, this again requires customizing the initial resin. Other options to reduce the cytotoxicity of a resin is post-processing with supercritical carbon dioxide [ 48 ], sonication of the material in isopropanol [ 49 ], or 10 days of incubation in cell growth medium [ 24 ] to leach harmful chemicals.…”

“…Previous cytotoxicity testing of photopolymers has mostly been performed with immortalized cell lines or in non-human species, which are not relevant for applications of printed cell culture devices in regenerative medicine [ 17 , 19 , 23 , 24 , 25 ]. Cell lines are commercially available and ensure a high reproducibility of large numbers of assays performed.…”

Biocompatibility of Blank, Post-Processed and Coated 3D Printed Resin Structures with Electrogenic Cells

“…In order to enhance the material palette FormLabs Dental LT (DLFLCL01) [ 33 ], FormLabs Flexible (FLFLGR0) [ 32 ], and Pro3dure GR-10 resins [ 34 ] were additionally tested after being subjected to post-treatment (IPA wash, 6 min of UV exposure, and autoclave) and material coating ( Figure 3 C). These resins were selected because of their commercial availability, and because they are all designated as biocompatible according to ISO standards [ 10 , 17 , 18 , 20 , 21 , 22 , 23 , 24 , 26 , 27 , 43 , 44 , 56 , 57 , 58 , 59 ]. Since PDMS showed the best biocompatibility results among all the coatings used with High Temp Resin, it was used as the coating in the abbreviated evaluation of these other resins.…”

“…Although this technology has revolutionized MEMS and microfluidics fields, to our knowledge, little investigation into the biocompatibility of the most commonly used commercial 3D printing resins has been performed to date. This is especially true for electrogenic or electrically active cells (e.g., neurons, cardiomyocytes) where no biocompatibility reports have been published as far as our knowledge goes [ 1 , 2 , 8 , 9 , 10 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Many of these “off-the-shelf” 3D printing liquid resins can be purchased directly from the individual printer manufacturers, and as a result their compositions are proprietary.…”