Oriented biological material for optical information storage and processing
First Claim
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1. A method of producing a stable reversible, high resolution image on a bacteriorhodopsin (BR)-containing film, comprising:
- dissolving polyvinyl alcohol PVA in a buffer to form a PVA solution;
dissolving a BR material which is optically switchable between first and second states in a buffer to form a BR solution;
adjusting the pH of said BR solution to produce a high pH BR solution;
mixing said PVA and high pH BR solutions to form a BR-PVA solution;
forming a film of said BR-PVA solution;
drying said film;
directing light of a first spectral range to selected locations in said film to expose selected BR molecules in said film to an optical image to switch the selected BR molecules from their first to their second state and thereby to switch the color of said exposed BR molecules to provide a corresponding image; and
directing light of a second spectral range to illuminate selected locations in said film to cause previously exposed BR molecules to emit light at a second harmonic of the illuminating light in said second spectral range to thereby nondestructively detect said image.
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Abstract
A stable, image-retaining, optically switchable film produced from a purple membrane in a high-pH polyvinyl alcohol solution forms an optical memory for data storage. The film, when dry, can be exposed to light to convert BR molecules to their M state, which is stable, and which allows long-term image storage. The image can be erased by exposing the film to yellow light to thereby switch all the molecules to the M state, and then a reverse image can be obtained using blue light. By controlling the location and wavelength of the incident light, pixels can be selected and exposed for information storage.
48 Citations
27 Claims
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1. A method of producing a stable reversible, high resolution image on a bacteriorhodopsin (BR)-containing film, comprising:
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dissolving polyvinyl alcohol PVA in a buffer to form a PVA solution; dissolving a BR material which is optically switchable between first and second states in a buffer to form a BR solution; adjusting the pH of said BR solution to produce a high pH BR solution; mixing said PVA and high pH BR solutions to form a BR-PVA solution; forming a film of said BR-PVA solution; drying said film; directing light of a first spectral range to selected locations in said film to expose selected BR molecules in said film to an optical image to switch the selected BR molecules from their first to their second state and thereby to switch the color of said exposed BR molecules to provide a corresponding image; and directing light of a second spectral range to illuminate selected locations in said film to cause previously exposed BR molecules to emit light at a second harmonic of the illuminating light in said second spectral range to thereby nondestructively detect said image. - View Dependent Claims (2, 3, 4, 5, 6, 18, 19, 20, 21, 22)
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7. A method of producing an oriented bacteriorhodopsin (BR)-polyvinyl alcohol (PVA) film capable of receiving a stable image for optical information storage, comprising:
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dissolving in a buffer a BR material capable of responding to light of a first spectral range of light energy to change its structure to an intermediate state which is capable of responding to a second spectral range of light energy to change back to said BR material, to thereby form a BR solution; dissolving in a buffer a PVA material to thereby form a PVA solution; mixing said BR solution and said PVA solution to produce a BR-PVA solution; spreading a volume of the BR-PVA solution on a substrate to form a BR-PVA film from said BR-PVA solution; diffusing a high pH buffer into said film before completely drying to control the orientation of said BR material in said film and to increase the stability of said BR intermediate state; and drying said film to a thickness of about 150 to 200 microns with an optical density of about 0.15, with the film having an absorption spectrum substantially the same as that of said BR material in said solution. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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23. A method of producing an oriented bacteriorhodopsin (BR)-polyvinyl alcohol (PVA) film capable of receiving a stable image for optical information storage, comprising:
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dissolving in a buffer a BR material capable of responding to light of a first spectral range of light energy to change its structure to an intermediate material which is capable of responding to a second spectral range of light energy to change back to said BR material, to thereby form a BR solution; dissolving in a buffer a PVA material to thereby form a PVA solution; mixing said BR solution and said PVA solution to produce a BR-PVA solution; spreading a volume of the BR-PVA solution on a substrate to form a BR-PVA film from said BR-PVA solution; and diffusing a high pH buffer into said film before completely drying to control the orientation of said BR material in said film and to increase the stability of said BR intermediate state; and drying said film to a thickness to produce an optical density of about 0.15, with the film having an absorption spectrum substantially the same as that of said BR material in solution. - View Dependent Claims (24, 25, 26, 27)
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Specification