Methods of making gels and films using curli nanofibers

1. A biologic hydrogel comprising a curli fiber and a surfactant, wherein the hydrogel comprises at least 3% (w/w) curli fiber, wherein the curli fiber comprises a wild-type CsgA or an engineered CsgA fusion protein, and wherein the engineered CsgA fusion protein comprises a CsgA polypeptide fused to an activity polypeptide.

2. The biologic hydrogel of claim 1 , wherein the activity polypeptide is a mucoadhesive polypeptide, a porin, a ribosomal protein or a plastocyanin.

3. The biologic hydrogel of claim 2 , wherein the mucoadhesive polypeptide is selected from the group consisting of: trefoil factor 1 (TFF1), trefoil factor 2 (TFF2), trefoil factor 3 (TFF3), and a microbial anti-inflammatory molecule (MAM) domain.

4. The biologic hydrogel of claim 1 , wherein CsgA fusion protein comprises a linker polypeptide linker sequence adjoining the CsgA polypeptide and the activity polypeptide.

5. The biologic hydrogel of claim 1 , wherein the engineered CsgA fusion protein further comprises a polypeptide tag selected from the group consisting of a poly-histidine tag, a myc tag, a FLAG tag, a hemagglutinin (HA) tag, and a V5 tag.

6. The biologic hydrogel of claim 1 , comprising a cell, wherein the cell is a bacterial cell, a mammalian cell, a protozoan, or a fungus.

7. The biologic hydrogel of claim 6 ,

wherein the cell is a bacterial cell, and wherein the bacterial cell comprises a heterologous nucleic acid, which comprises a heterologous gene encoding the engineered CsgA fusion, or

wherein the bacterial cell comprises a heterologous nucleic acid, which comprises a heterologous gene encoding a polypeptide selected from the group consisting of an extracellular matrix component, a therapeutic polypeptide, a mucoadhesive polypeptide, a cytokine, an enzyme, an antibody, or an antibody mimetic sequence.

8. The biologic hydrogel of claim 1 , wherein the hydrogel comprises a nucleic acid, an extracellular matrix component, a polysaccharide, a metabolite, a metal ion, a nanoparticle, a polypeptide, cellulose, a vitamin, a nutraceutical, or a detectable compound.

9. The biologic hydrogel of claim 1 , wherein the biologic hydrogel is suitable for use in an application selected from the group consisting of: biocatalysis, chemical production, filtration, isolation of molecules from an aqueous solution, water filtration, bioremediation, nanoparticle synthesis, nanowire synthesis, display of optically active materials, surface coating, structural reinforcement of an object, and delivery of a therapeutic agent, or wherein the biologic hydrogel is suitable for use as a therapeutic biomaterial, a biological scaffold, a delivery system for therapeutic agents, a biosensor, a biocatalyst, a coating, and an electronically conductive material.

10. A particle comprising the biologic hydrogel of claim 1 .

11. A pharmaceutical composition comprising the biologic hydrogel of claim 1 , and a pharmaceutically-acceptable excipient.

12. The biologic hydrogel of claim 1 , wherein the hydrogel comprises at least 5% (w/w) curli fiber.

13. The biologic hydrogel of claim 12 , wherein the hydrogel comprises at least 10% (w/w) curli fiber.