Methods & Materials
Design description.
An Anycubic Kossel Linear Plus Delta 3D printer kit was selected for
modification. Based on the criteria for bioprinting, both the hardware
and software of the Delta printer was successfully modified to
accommodate for tissue engineering purposes. The manufacture and
assembly of the final delta bioprinter can be separated into three main
parts; (1) the hardware modification of the 3D printer frame, (2) the
replacement of the thermoplastic extruder for a cell-free hydrogel paste
extruder, and (3) the software modifications for hydrogel paste
extrusion. Majority of the added components were 3D printed – making it
inexpensive and easily modified as necessary. A leadscrew driven
hydrogel deposition concept is employed within the system and due to the
modular nature of the extruder parts, the RRP system easily allows for
adjustments regarding the use of different syringe diameters and
volumes.
All 3D printed parts mentioned were printed using an ANYCUBIC Kossel
Delta Linear Plus 3D printer following the same general printing
parameters as listed: Layer height: 0.1 mm, Fill density: 100 %, Print
speed: 80 mm/s, Printing temperature: 210 ̵̊C, 100 % Flow, No support
structures unless necessary and No platform adhesion. Poly-L-lactic acid
(PLA) was used as the printing material (1.75 mm diameter eSUN PLA+ 3D
filament). No additional post-print processing was required. The 3D
modelling software SketchupMake2017 (v.17.2.2555) was used to design all
printed parts (unless otherwise specified) and the slicing software Cura
(v.15.04.2) used to prepare the design files for further 3D printing.
Bioprinter Frame (Hardware) modifications
Enclosure: The printer was enclosed using both printed and
non-printed parts (Fig 1a). The side frames and mid-sections (later
referred to as bioprinter frames, windows, and doors) were designed and
files sent for manufacture to a Perspex laser cutting service (M&D
Creations, Makhanda, South Africa) using 3 mm thickness clear Perspex
sheets. The 3D printed parts consist of three separate corners.
Board box: The Anycubic Tri-gorilla controller board was moved
from under the build plate (as per printer design) to outside the
system; shown in Fig 1b. Wiring was adjusted to accommodate for the new
board position. A board box was designed, and 3D printed to accommodate
for the new location of the board. Furthermore, a few changes were made
to the electronic board such that the hotbed power input cables and fans
were removed.
Bed platform : A new bed platform was designed, and 3D printed,
to hold two 220 mm diameter glass plates of 2 mm thickness (Fig 1b). The
bed platform with the glass in place was designed to cover most of the
base of the printer with a few openings to allow for air flow to reduce
any pressure build-up.