Hydrogel compositions and methods of use thereof
A two-component hydrogel matrix system is provided, which system is useful in a variety of cell growth uses, including without limitation three-dimensional culture systems. The components comprise modified hyaluronic acid (HA); and modified elastin-like proteins (ELP). Variables of HELP, including for example, matrix stiffness, matrix stress relaxation rate, and cell-adhesive-ligand concentration, can be independently and quantitatively specified.
1 . A two-component hydrogel matrix system comprising: a first component comprising a defined ratio of hyaluronic acid (HA) modified to comprise a pendant reactant group benzaldehyde; and a second component comprising an elastin-like protein (ELP) modified to comprise a pendant reactant group hydrazine group; wherein cross-links between the first component and the second component are formed to generate a hydrogel upon mixing.
2 . The system of claim 1 , wherein matrix stiffness is independently tuned by varying the ratio of the reactant groups present on the first component, to reactant groups present on the second component.
3 . The system of claim 1 , wherein the ratio of reactant groups is varied by one or more of: specifying the number of reactant groups on HA; specifying the number of reactant groups on ELP; and specifying the ratio of HA:ELP.
4 . The system of claim 1 , wherein the ELP comprises from 1 to 7 elastin-like motifs.
5 . The system of claim 4 , wherein the elastin-like motifs are selected from SEQ ID NO:23, 24 and 25.
6 . The system of claim 1 , wherein the ELP comprises a cell adhesive domain from 15 to 45 amino acids in length, comprising one or more cell adhesion sequence motifs, or scrambled or lacking RGD.
7 . The system of claim 6 , wherein the cell adhesion motifs are selected from RGD or any of SEQ ID NO:3 to SEQ ID NO:9.
8 . The system of claim 1 , wherein the ELP comprises one or both of SEQ ID NO: 1 and SEQ ID NO:2.
9 . The system of claim 1 , wherein the cell-adhesive peptide concentration of the hydrogel is tuned by varying the ratio of ELP comprising a cell adhesive motif to ELP lacking a cell-adhesive motif.
10 . The system of claim 7 , wherein the ratio of ELP comprising a cell adhesive motif to ELP lacking a cell-adhesive motif is from 100:0 to 0:100.
11 . The system of claim 1 , wherein the ELP comprises from 3 to 20 hydrazine groups.
12 . The system of claim 1 , wherein the hydrogel comprises up to about 1.5 mM RGD.
13 . A hydrogel formed from the system of claim 1 .
14 . A method of culturing a mammalian cell, the method comprising encapsulating an initiating population of mammalian cells in a hydrogel of claim 13 , and maintaining the encapsulated cells in a suitable medium.
15 . The method of claim 14 , wherein the initiating cell population comprises a single cell suspension or a tissue explant.
16 . The method of claim 14 , wherein the cell population comprises stem cells.
17 . The method of claim 14 , wherein the initiating cell population differentiates into organoids in culture.
18 . The method claim 14 , wherein encapsulated cells are passaged by enzymatically degrading the hydrogel.
19 . The system of claim 1 , wherein the molecular weight of the HA is from 20 kDa to 100 kDa.
20 . The method of claim 16 , wherein the stem cells comprise epithelial cells.