Table 5A.

Hydrogel subtypes based on their source:

Subtypes	Advantages	Disadvantages
Polymeric natural hydrogels	Contains integrin binding sites that allows cell attachment and signal transduction between the microenvironment and cells. Biodegradable. Low reproducibility Promotes viability, growth, differentiation, and allow migration of cells.	Physical and mechanical properties are unknow. Poor mechanical properties, tend to dissociate easily. Limited tunable properties Introduces variables into the culture conditions. Contains endogenous growth factors and cytokines. Immunogenic Spheroids generated in 4–5 days. Challenging to handle at low temperatures. Post culture recovery is limited.
Polymeric synthetic hydrogels	Physical and mechanical properties are know. Posses tunable properties – responds to changes in pH, temperature, light etc. Higher reproducibility,	Biologically inert Not biodegradable. Spheroids generated in 4–5 days. Porosity can be controlled. Post culture recovery is limited.
Semisynthetic hydiogels	Physical and mechanical properties are know and can be controlled. Contains active motifs and peptides found on intergrin binding ligands. Higher reproducibility. Requires addition of exogenous growth and other soluble factors. Distribution and concentration of ligand binding sites can be controlled.	May require harsh pH and temperature adjustments for hydrogelation, which can damage cells. Spheroids generated in 4–5 days. Post culture recovery is limited.
Molecular peptide hydrogels	Biologically active. Posses enhanced biodegradability Can be enzymatically cleaved. Control the length of the peptide and its composition. Self-assembling, undergoes hydrogelation at physiological temperature. Cells remain viable during hydrogelation and cell recovery.	Spheroids generated in 4–5 days. Post culture recovery of embedded cell is possible after dissolution of the matrix.