3D-printed biological organs: medical potential and patenting opportunity

Figures & data

Table 1. The classes of bioprinting techniques and their advantages and disadvantages.

Classes of methods (and cited example)	Technology highlights	Advantages	Disadvantages
Extrusion of highly viscous hydrogel (with or without the cells) along with plastic polymers that make a solid-state framework [3]	–High-viscosity hydrogel materials, with or without the cells, are mechanically extruded. –Cells are embedded between the spaces of extruded hydrogel. –Solid-state polymers are also printed.	–High viscosity of the hydrogel can partially support the printed three-dimensional (3D) structure. –Solid polymer-based framework can provide structural rigidity.	–Hydrogel alone cannot entirely support the 3D morphology. –Viscous material and its continuous extrusion limit the printing resolution and ability to create complicated morphology. –The mechanical characteristics of the solid framework may limit the scope of applications.
3D micro-assembly/printing [4]	–Hydrogel–cell aggregates/pellets are prepared and assembled with hydrogel rods in 3D. –Combinatory placement of spherical cell aggregates and the linear rods produces tissue topology, including large tubular structures.	–Cells are prepared in large numbers as an aggregate, and it expedites cell integration/fusion during culture. –The manufacturing process can be also expedited due to the use of preassembled cell–hydrogel units.	–The micro assembly technique and (relatively) large cell-aggregates limit the printing resolution and the ability to create complicated on-demand morphology, including capillary-level vascular systems. –Printing multiple cell lines on to substrates with high-spatial resolution is difficult due to the use of large, pre-made cell aggregates. –The material characteristics of hydrogel-rods may limit the scope of applications. –The 3D cellular hydrogel construct may require additional mechanical support.
3D bioprinting with phase-changing hydrogel [5-9,11,12]	–Liquid state, phase-changing hydrogel precursors are printed at high-spatial resolution. –Various types of cells, prepared in a liquid-state suspension, are printed separately and embedded into the hydrogel. –Novel layer-by-layer gelation process enables the formation of the desired 3D structures.	–Versatile printing features allow for the demonstration of various tissue topologies and functions in 3D. –Capillary-level angiogenesis/vascularization models have been demonstrated, along with on-demand construction of fluidic channels and embedment of growth factors.	–The choice of hydrogel precursor materials may limit the scope of applications. –The 3D cellular hydrogel construct may require additional mechanical support.

Table 2. Potential patenting areas in three-dimensional (3D) bioprinting.

Areas of potential IP	Examples of possible IP contents
Hydrogel/extracellular matrices (ECM) materials	–New formulation of ECM/hydrogel precursor materials with tissue-like functional properties with inert immunological responses. –Novel methods on how to derive/synthesize such materials.
Isolation and growth/differentiation of cells in the context of bioprinting	–Novel methods on how to derive cells, either primary or pluripotent, that can be used as sources for bioprinting. –Methods to prepare the cells for printing, with or without the combination of scaffold materials.
Bioreactor/method to grow printed organ precursors	–Methods of integration and coupling of printed organ precursors with the external bioreactors. –Development of modular bioreactor/bioreactor components that sub-serve different culture conditions. –Novel methods that enable automated organ growth after printing.
Methods of dispensing/printing techniques	–Single-cell precision loading and dispensing of various types of cells –Method to improve speed of printing, for example, deployment of multiple dispensing arrays. –Novel methods to dispense liquid materials with higher viscosities, in form of droplets, which may broaden the choices of printable materials.
Methods of novel 3D fabrication techniques	–Hybrid approaches to constructively enhance the current 3D printing principles.

IP: Intellectual property.

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