Biocompatibility of 3D-Printed Methacrylate for Hearing Devices

Abstract

The capacity of 3D printing (3DP) technologies to initiate speedy polymerization of solvent-free resins accounts for their utility in the manufacturing of medical devices. Nonetheless, independent biological evaluation of 3D-printed materials is recommended due to the unique parameters of the manufacturing process, which can influence their physical, chemical and biological properties. In this study, E-Shell 450 clear methacrylate indicated for 3DP of hearing devices was examined for biological safety using zebrafish bioassays adapted to Organization for Economic Cooperation and Development (OECD) fish embryo test. In addition, the proprietary material was characterized for composition using headspace gas chromatography–mass spectrometry (GC–MS). To initiate the biological test, newly fertilized zebrafish eggs were cultured on non-treated and ethanol-treated methacrylates in glass petri dishes with ultrapure water, incubated at 28.5 °C and assessed for developmental endpoints of toxicity at 24 h intervals until 96 h. Toxicological data indicate that non-treated methacrylate is extremely toxic in zebrafish bioassays, whereas ethanol-treated counterpart showed a relative lower toxicity possibly due to ethanoic–aqueous interactions as observed by GC–MS. With the current influx of 3D printing materials, users are urged to exercise caution. Operators must also take cognizance of the potential toxicity of the chemicals used in 3DP and implement safety measures to limit their exposure.

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.…”

Biomedical photopolymers in 3D printing

“…Table I shows compositional differences between liquid and photocured resins; data for the latter were obtained in-house using gas chromatography – mass spectrometry (GC-MS) protocols (Alifui-Segbaya and George, 2018). Also, the gradations of toxicity (Figure 3) elicited by the photocured materials in zebrafish bioassays (Alifui-Segbaya et al , 2017a) were possibly influenced by their physicochemical characteristics before and after immersion in ethanol (Alifui-Segbaya et al , 2018).…”

“…The Organization for Economic Cooperation and Development fish embryo toxicity (FET) test designed to determine acute toxicity of chemicals on embryonic stages of zebrafish (Oecd Test Guideline 236, 2013) has been successfully applied to toxicity profiling of photopolymers in 3DP (Oskui et al , 2016; Macdonald et al , 2016; Alifui-Segbaya et al , 2017a; Alifui-Segbaya and George, 2018; Alifui-Segbaya et al , 2018). The wild-type strain recommended for chemical screening is also popular for research related to sequencing, genetic screening, gene expression and transgenesis (Haper and Lawrence, 2011).…”

Bioprinting: Prospects, considerations and challenges for application in South African clinical environments

“…[21] AM is proving to be vital in many patient-specific therapies that rely heavily on the ability to customise treatments to individual patients. Hearing aids, [22] drug delivery methods, [23,24] dental, [25] orthopaedic [26] and paediatric implants [27] are a few of the therapies that have been revolutionised by the development of AM technologies. Furthermore, in the hope of reducing complication rates, researchers have found 3D printing to be invaluable in providing medical students with more realistic models for better preparation before performing complicated surgeries on real patients.…”