Tannin-chitosan composites
The invention provides a composition comprising a matrix of chitosan and a tannin wherein the chitosan is electrostatically bonded to the tannin to form a chitosan-tannin composite material. The chitosan can be partially or fully deacetylated, and the tannin can be a monomeric or an oligomeric proanthocyanidin or a hydrolysable tannin. The chitosan-tannin composite material can be a nanoparticle, a hydrogel film, a bio-foam, or a biogel, or the chitosan-tannin composite material can coat a liposome. The composite materials can be used for drug delivery, for antibacterial and/or antifungal applications, for tissue engineering applications, for wound healing applications, or they can be used as adjuvants for vaccination, including oral vaccinations. The invention also provides methods of preparing the composite materials and their various forms.
1. A composition comprising a matrix of chitosan and tannins, wherein the tannins comprise one or more oligomeric proanthocyanidins or oligomeric hydrolysable tannins, wherein the chitosan is electrostatically bonded to the one or more oligomeric proanthocyanidins or oligomeric hydrolysable tannins via hydrogen bonding, and wherein the matrix of chitosan and tannins is in the form of a chitosan-tannin composite material.
2. The composition of claim 1 wherein the chitosan has a deacetylation degree of about 70% to about 100%.
3. The composition of claim 1 wherein the mean molecular weight of the chitosan component is about 170 kDa to about 400 kDa.
4. The composition of claim 1 wherein the mass of the tannins is about 1% to about 50% of the mass of the chitosan.
5. The composition of claim 1 wherein the mass of the tannins is from about 1:99 to about 5:1 the mass of the chitosan.
6. The composition of claim 1 , wherein the tannins comprise less than about 3 wt. % monomeric tannin components.
7. The composition of claim 1 wherein the tannins comprise a proanthocyanidin.
8. The composition of claim 7 wherein the proanthocyanidin has a degree of polymerization of 4, 5, 6, 7, 8, or 9, and the proanthocyanidin has at least one A-type interflavan bond.
9. The composition of claim 1 wherein the tannins comprise a hydrolysable tannin.
10. The composition of claim 9 wherein the hydrolysable tannin comprises 2-5 glucose units in its core structure.
11. The composition of claim 9 wherein the hydrolysable tannin comprises punicalagin.
12. The composition of claim 1 wherein the composition is a nanoparticle, a hydrogel film, a bio-foam, a biogel, or the composition forms a coating on the surface of a liposome.
13. The composition of claim 1 wherein the chitosan-tannin composite material is in the form of a nanoparticle that has a diameter of about 100 nm to about 350 nm.
14. The composition of claim 1 wherein the tannins comprise less than 5 wt. % monomeric tannin components.
15. The composition of claim 1 wherein the chitosan and tannins are distributed throughout the matrix.
16. A composition for oral vaccination comprising a chitosan-tannin composite nanoparticle of claim 12 and an antigen.
17. The composition of claim 16 wherein the antigen is a protein, a peptide, a nucleic acid, or DNA, and wherein the antigen is encapsulated in the nanoparticle or adsorbed to the surface of the nanoparticle.
18. A composition comprising a matrix of chitosan and tannins, wherein the tannins comprise one or more oligomeric proanthocyanidins or oligomeric hydrolysable tannins, wherein the chitosan is electrostatically bonded to the one or more oligomeric proanthocyanidins or oligomeric hydrolysable tannins via hydrogen bonding, wherein the matrix of chitosan and tannins is in the form of a chitosan-tannin composite material, and wherein the composition is a bio-foam, or the composition forms a coating on the surface of a liposome.
19. A method for delivering a bioactive agent to a mammal comprising administering to a mammal the composition of claim 1 , wherein the chitosan-tannin composite material is in the form of a nanoparticle that encapsulates the bioactive agent.
20. A method to inhibit bacterial growth or fungal growth in a plant comprising contacting a plant infected with bacteria or fungi with an effective amount of a chitosan-tannin composite material of claim 1 , wherein the composite material inhibits the bacterial growth or fungi growth in or on the plant.
21. The method of claim 20 wherein the bacteria is of the genera Erwinia or Xanthomonas , or wherein the fungi is of the genera Bothytis or Fusarium.
22. A method of oral vaccination comprising orally administering a chitosan-tannin composite nanoparticle and an antigen, wherein the tannin composite nanoparticle comprises a matrix of chitosan and tannins, wherein the tannins comprise one or more oligomeric proanthocyanidins or oligomeric hydrolysable tannins, wherein the chitosan is electrostatically bonded to the one or more oligomeric proanthocyanidins or oligomeric hydrolysable tannins via hydrogen bonding.