title: Extraction and purification of purple membrane for photochromic thin film development: application in photoelectrochemical investigation.
abstract: Purple membrane (PM) has been extracted and purified from archaebacteria for thin film development. The purified purple membrane is isolated in 1 % polyvinyl alcohol solution for making thin film within gelatin and organically modified silicate matrices. For thin film within gelatin matrix, homogenized purple membrane suspension is mixed with 8 % gelatin and poured into a specially designed block with desired thickness of spacer having hydrophobicity followed by gelatinization of the same over home-made thermostatic control unit at 38 °C. The gelatinized matrix is then allowed to dry under controlled conditions of humidity and temperature. The films of varying thicknesses ranging between 40, 50, and 60 μ are used for photo-electrochemical measurements. The results on photo-electrochemistry of non-oriented purple membrane film provides valuable information on the generation of forward (light on) and backward (light off) photocurrent as a function of: (a) applied potential and (b) film thickness. An increase in applied negative potential increases the amplitude of photocurrent whereas decrease in film thickness facilitates the reversibility of photocurrent response.
authors.affiliation: Department of Applied Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India. pcpandey.apc@itbhu.ac.in
authors.forename: P C
authors.initials: PC
authors.lastname: Pandey
authors.forename: Digvijay
authors.initials: D
authors.lastname: Pandey
authors.forename: Richa
authors.initials: R
authors.lastname: Singh
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry; D002458:Cell Fractionation / Q000379:methods*; D003116:Color; D004563:Electrochemistry / Q000379:methods*; D019617:Halobacterium salinarum / Q000166:cytology; D055767:Immobilized Proteins / Q000737:chemistry; D055620:Optical Phenomena; D055668:Photochemical Processes; D011142:Polyvinyl Alcohol / Q000737:chemistry; D018717:Purple Membrane / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013053:Spectrophotometry; D013535:Suspensions; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D055767:Immobilized Proteins; D013535:Suspensions; D017971:Tin Compounds; D001436:Bacteriorhodopsins; D012822:Silicon Dioxide; D011142:Polyvinyl Alcohol; C045358:stannic oxide