1. Scope

1. Scope 1.1 This is guide is a resource for bioprinting tissue-engineered medical products (TEMPs) with bioinks and biomaterial inks. There are existing standards that cover biomaterials and scaffolds in a more general fashion (ASTM F2150, ASTM F2027, ISO 10993). This guide focuses specifically on extrusion bioprinting utilizing bioinks and biomaterial inks with inherent or inducible fluidic properties with or without encapsulated cells used to construct TEMPs. For the remainder of this guide, both bioinks and biomaterial inks will be collectively referred to as bioinks. 1.2 For the purposes of this guide, bioprinting is defined as the deposition of bioinks in a prescribed layer-by-layer stacking organization to fabricate engineered tissues and organs (derived from the ASTM Standard Test Method for Printability of Bioinks for Extrusion-based Bioprinting effort). 1.3 TEMPs may be produced by many different bioprinting modalities, including but not limited to the following: electrospinning, electrospray, extrusion-based, droplet-based, inkjet-based, and laser-assisted bioprinting. Extrusion-based bioprinting is the primary focus of this document since it is currently the most well-understood modality used to construct TEMPs, but other bioprinting modalities are also addressed. 1.4 This guide will focus on bioinks and biomaterials used as inks with inherent or inducible fluidic properties. These inks may or may not contain encapsulated cells. Chemical properties of the inks and other factors that affect printability are addressed. 1.5 Pre-printing and printing considerations are the focus of this guide, but considerations regarding post-printing product stabilization are also addressed. 1.6 This guide will address assessments regarding the sterility and cytocompatibility of bioinks, including chemical and physical benchtop tests as well as measures of post-printing cell viability. 1.7 This standard does not purport to address all of the safety concerns associated with bioprinting and the use of bioinks and biomaterial inks. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Some broad bioink-user safety considerations are addressed in the applicable sections.

Keywords

Tissue Engineering; Tissue engineered medical product (TEMP); bioinks; biomaterials; bioprinting; biomaterial inks; extrusion-based; encapsulated cells

Rationale

This work item is being initiated to provide bioinks and biomaterial ink best practices. The need for this standard was expressed in multiple arenas, including but not limited to, the F04.42 subcommittee discussion NOV 2018, Advanced Regenerative Manufacturing Institute's (ARMI) BioFabUSA Standards Working Group in a bioprinting standards discussion held 16 APR 2019, and also exhibited in the Standards Coordinating Body (SCB) Needed Standards Report JAN 2020. This standard guide in an effort toward establishing common best practices for bioink properties and printing parameters to allow product developers to more easily characterize products, reproduce test results, and control product quality.

The title and scope are in draft form and are under development within this ASTM Committee.