Lifeink® 300 and Collagen
One of the drawbacks to gelatin is the relatively low resolution (ie. 25 gauge needle) and high PSI required for consistent extrusion. One way to improve the shear-thinning of methacrylated gelatin bioinks is to mix in type I collagen. The collagen also adds additional native cell binding sites to improve cell viability.
Image provided by Khoon Lim, University of Otago
Lifeink® 300 / Collagen Instructions
New Visible-Light Photoinitiating System for Improved Print Fidelity in Gelatin-Based Bioinks
Khoon S. Lim, Benjamin S. Schon, Naveen V. Mekhileri, Gabriella C. J. Brown, Catherine M. Chia, Sujay Prabakar, Gary J. Hooper, and Tim B. F. Woodfield
ACS Biomaterials Science & Engineering 2016 2 (10), 1752-1762
Prepare Lifeink® 300 as 20wt% solution in 1X PBS
Maintain at 30°C
Neutralize PhotoCol® Methacrylated Type I collagen as a 1% solution
Add desired photoinitiator to the Lifeink® 300.
Mix Lifeink® 300/photoinitiator mixture and PhotoCol® in a 1:1 ratio.
Add concentrated cells if desired to the bioink.
Target final cell concentration of 5-10M/mL)
Pipette the solution into the desired printing syringe and allow to equilibrate at 22°C for ~15 minutes.
Print with a 24-25G needle onto a chilled printing dish (this helps solidify the structure as it is being printed).
Use needles that block gelatin exposure to UV light (ie. metal needles).
Crosslink appropriately using required light source.
Reduce clogging and improve printability of methacrylated gelatin by mixing in collagen.
Printing with Lifeink® 300 / FibriCol® mixture
Use these parameters as a starting point. Individual printers and bioink formulations (ie. protein concentration, cell density/volume, etc..) will require modified parameters. These parameters have been set using a pneumatic based printer.
Extrusion type: pneumatic
Pressure: 25 PSI
Print head temperature: 20°C
Needle size: 25G (250 micron inner diameter)
Layer Height: 0.2 mm
Nozzle Diameter: 0.2 mm
Print Speed: 6mm/s