Bioinks Explained: Hydrogels, Collagen, GelMA and Beyond
The ink is where biology meets engineering. A cheat sheet to the most common bioinks and what each one is good for.
A bioink has a contradictory job description: it must flow through a nozzle like a liquid, then hold its shape like a solid, all while keeping cells alive and happy. Most bioinks are hydrogels, water-swollen polymer networks that mimic the body’s extracellular matrix.
The usual suspects
- Alginate: from seaweed. Gels instantly with calcium. Cheap and printable, but cells can’t grab onto it easily.
- Gelatin & GelMA: gelatin methacryloyl can be crosslinked with light, giving tunable stiffness. A lab favorite.
- Collagen: the body’s most abundant protein. Very biological, but soft and tricky to print (see FRESH).
- Fibrin: the clotting protein. Great for vascular and wound applications.
- Hyaluronic acid: common in cartilage and skin work.
- dECM: decellularized extracellular matrix, made by washing cells out of real tissue, keeps tissue-specific biochemical cues.
Three properties to check
- Printability: shear-thinning behavior and shape fidelity.
- Biocompatibility: cell survival during and after printing.
- Degradation: the scaffold should break down as cells build their own matrix.
Tip: starting out? Practice with cell-free alginate or Pluronic to tune your printer settings before you ever touch cells.
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