1. Hydrogels:

• Synthetic polymers which have the ability to swell.
• Especially used in drug delivery applications with less swelling controlled by factors such as polymer material, viscosity and shear stress.

2. Ceramic-based inks:

• High stiffness and provides a surface in bone tissue development.
• commonly used inks are Hydroxyapatite and Tricalcium phosphate which enhances the strength in scaffolds.

3. Polymer-based inks:

• Polylactic acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) are extensively used in 3d printing.
• Engineering applications, prototyping, assists in bone formation and regeneration.

4. Composite inks:

• Two major types hydrogels and polymer based inks enhances mechanical properties and bioactivity.
• Accelerates healing and primarily used in tissue engineering applications.

Note: Current bio inks has limited alteration in properties and i future it may applied to vast number of applications.