3D PRINTING AND NANOMANUFACTURING - 3D Bioprinting and Nanotechnology in Tissue Engineering and Regenerative Medicine - page 29

2.2.5 BIOLOGICAL LASER PRINTING
Biological laser printing (BioLP) was developed by Barron et al . ( Barron et al . , 2004, 2005; Pirlo
et al . , 2012; Othon et al . , 2008 ). It is similar to the previous two processes, LIFT and MAPLE DW,
illustrated in Figure 2.3 . BioLP utilizes an optically transparent quartz instead of the glass slide used in
LIFT. Metal or metal oxide is coated on the quartz support as the laser absorption layer. The biomate-
rial layer with cells, such as powder, liquid, or gel, is coated on the laser-absorbing layer. The incident
laser energy is focused and absorbed at the interface of the quartz support and laser absorption layer.
The heat generated by the laser absorption layer causes vaporization of water in the biomaterial. The
biomaterial is then transferred from the ribbon surface to the receiving substrate surface. Thus, this
technique reduces potential damage to biological materials.
2.2.6 STEREOLITHOGRAPHY TECHNIQUES
The stereolithography (STL) technique was developed by Hull in 1986 and was described in his patent
“Apparatus for Production of Three-Dimensional Objects by Stereolithography” ( Hull, 1986 ). Stereo-
lithography is a technique of producing parts one layer at a time by curing a photoreactive resin with
a UV laser or another similar power source. In addition to using a single-point laser, stereolithog-
raphy can be performed with a digital micromirror-array device (DMD) ( Suri et al . , 2011; Gauvin
et al . , 2012; Soman et al . , 2012, 2013; Lin et al . , 2012 ). The DMD is an array of up to several millions
FIGURE 2.4
Schematic setup of the DOPsL system ( Zhang et al. , 2012 ).