Photochromic material comprising a proteorhodopsin apoprotein and a retinal analog
The present invention relates to a photochromic material comprising a proteorhodopsin apoprotein and a retinal analog. In one embodiment, the retinal analog is an azulenic retinoid compound. In another embodiment, the retinal analog is a compound that is structurally similarly to all-trans-retinal. The proteorhodopsin apoprotein and the retinal analog form a photochromic material having different spectral properties from those of a corresponding photochromic material formed by the same proteorhodopsin apoprotein and all-trans-retinal. In one embodiment of the application, the retinal analog-containing proteorhodopsin has an absorbance spectrum that does not overlap significantly with that of all-trans-retinal-containing proteorhodopsin. In another embodiment of the application, the retinal analog-containing proteorhodopsin yields a red-shifted visual chromophore compared with the all-trans-retinal-containing proteorhodopsin chromophore. The photochromic material of the present invention is useful as an optical data storage carrier, a fraud-proof optical data carrier, security ink, and in other optical applications.
1. A photochromic material comprising a proteorhodopsin apoprotein and an azulenic retinoid compound of Formula I,
wherein R′, R″ and R′″ are each independently H, C 1-4 straight chain alkyl, or C 1-4 branched chain alkyl,
n is an integer from 1 to 4;
X a and X′ b are each independently H, C 1-4 alkyl, F, Cl or CF 3 ;
Y is absent, or Y is a para-, meta-, or ortho- phenyl; and
Z is CHO.
2. The photochromic material according to claim 1 , wherein said R′, and R′″ are a C 1-4 straight chain alkyl, and R″ is a C 1-4 branched chain alkyl.
3. The photochromic material according to claim 2 , wherein R′=R′″=methyl, and R″=isopropyl.
4. The photochromic material according to claim 1 , wherein Y is absent.
5. The photochromic material according to claim 1 , wherein said azulenic retinoid compound is selected from the group consisting of Compound A, B, C, D, E, F, C, H, I, J, K, L, M, and N:
6. A photochromic material comprising a proteorhodopsin apoprotein and a retinal analog, wherein said retinal analog is selected from the group consisting of p-dimethyl aminocinnamaldehyde, Compound O, P, Q, R and S:
P-dimethyl aminocinnamaldehyde
7. The photochromic material according to claim 1 or 6 , wherein said photochromic material has spectral properties different from the spectral properties of a corresponding photochromic material comprising said proteorhodopsin apoprotein and all-trans-retinal.
8. The photochromic material according to claim 7 , wherein said photochromic material has an absorption spectrum that does not overlap significantly with the absorption spectrum of the corresponding photochromic material.
9. The photochromic material according to claim 7 , wherein said photochromic material has a maximum absorbance wavelength that is red-shifted compared with the maximum absorbance wavelength of the corresponding photochromic material.
10. The photochromic material according to claim 9 , wherein the maximum absorbance wavelength of said photochromic material is between 550 and 750 nm.
11. The photochromic material according to claim 10 , the maximum absorbance wavelength of said photochromic material is between 600 and 700 nm.
12. The photochromic material according to claim 1 or 6 , wherein said proteorhodopsin apoprotein is derived from BacA8 or a mutant thereof.
13. The photochromic material according to claim 1 or 6 , wherein said proteorhodopsin apoprotein is derived from Hot75 ml or a mutant thereof.
14. A solid material comprising the photochromic material according to claim 1 or 6 .
15. The solid material according to claim 14 , wherein said solid material further comprises one or more hydrophilic polymers that are capable of forming a homogeneous phase with said photochromic materials prior to solidification to a solid form.