Photoelectric Monolayers Based on Self-Assembled and Oriented Purple Membrane Patches

Al-Aribe, Khaled M.; Knopf, George K.; Bassi, Amarjeet

doi:10.1109/jmems.2011.2159092

Cited by 13 publications

(14 citation statements)

References 44 publications

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“…BR is a visual pigment extracted from the purple membrane (PM) of the archae Halobacterium salinarum , a micro‐organisms found in low‐oxygen and salt‐rich environments such as the Dead Sea . BR can provide binary responses without chromophore expulsion and remains stable for several years even when exposed to sunlight for prolonged periods of time . BR functions as a light driven proton pump by enabling hydrogen ions to pass through it from the cytoplasmic to the extracellular environment .…”

Section: Visionmentioning

confidence: 99%

“…By labelling the extracellular side of the BR and PMs with biotin they were able to orientate them on a gold surface. Biotinylation of the BR was realized by coupling biotin ester to a lysine residue on the extracellular side of the BR at pH 8.5 . Orientating the films makes it possible to place them onto the electrodes with the cytoplasmic side of film towards a grounded ITO conductive surface and the extracellular side in contact with the second ITO electrode used for input of the measurement .…”

Section: Visionmentioning

confidence: 99%

“…Biotinylation of the BR was realized by coupling biotin ester to a lysine residue on the extracellular side of the BR at pH 8.5 . Orientating the films makes it possible to place them onto the electrodes with the cytoplasmic side of film towards a grounded ITO conductive surface and the extracellular side in contact with the second ITO electrode used for input of the measurement . The biotinylated BR was then attached to the gold surface via streptavidin‐biothin interactions …”

Section: Visionmentioning

confidence: 99%

“…Most vertebrae pigments are unsuitable for incorporation into devices because they are ejected out of the binding pocket of the rhodopsin protein, duringp hotoisomerisation [169].T hey then have to be regenerated as described in section 4.1.1 which significantly complicates device design [178] [177,179].T os olve this problemm any researchers have turnedt ob acteriorhodopsin (BR) [180]. BR is av isual pigment extracted from the purple membrane (PM) of the archae Halobacterium salinarum, amicro-organisms found in low-oxygen and salt-rich environments such as the Dead Sea [181].B Rc an provide binary responses without chromophore expulsion and remains stable for severaly ears even when exposed to sunlight for prolongedp eriods of time [180,182].B Rf unctions as al ight driven proton pumpb ye nabling hydrogen ions to pass through it from the cytoplasmic to the extracellulare nvironment [183].T his generates ap roton gradient which is usedi na naerobic photosynthesis to drivea denosinet riphosphate (ATP) production [183][184][185][186]. Similar to opsinG PCRs,BRi satransmembrane protein composed of seven a-helices with ar etinal chromophore bound covalently via al ysine residue [186][187][188].W hen ap hoton is absorbed by the retinal chromophore, the chromophoreu ndergoes ap hotocycle consisting of six steps as seen in Figure 14.…”

Section: Bacteriorhodopsinmentioning

confidence: 99%

“…Thet wo electrodes are separated by ap olyester spacer. TheB Rf ilms are prepared using Electrophoretic Sedimentation (EPS) technique to achieve partial orientation of the BR via al ow electric field [183,185].A nother interestingp hotocell-based sensor was reported by Bassi and et al who useds elf-assembly techniques to produce dry ultrathin PM monolayers.B yl abelling the extracellular side of the BR and PMs with biotin they werea ble to orientate them on ag old surface.B iotinylationo ft he BR was realized by coupling biotin estert oalysine residue on the extracellular side of the BR at pH 8.5 [182].O rientating the films makes it possible to place them onto the electrodes with the cytoplasmic side of film towards ag rounded ITOc onductive surface and the extracellular side in contact with the second ITO electrode used for input of the measurement [182].T he biotinylated BR was then attached to the gold surface via streptavidin-biothin interactions [197].…”

Section: Special Issuementioning

confidence: 99%

See 4 more Smart Citations

Sensor Devices Inspired by the Five Senses: A Review

Svechtarova¹,

Buzzacchera²,

Toebes³

et al. 2016

Electroanalysis

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1IntroductionWearable sensor technology is at the forefront of popular media and at the same time is the subject of intense activity in the scientific world. Thes cientificallyd rivenq uantified self focuseso nc ollecting data on the human state to gather information to improve quality of life,t he more extreme end of the spectrume ncompasses biohacktivism and the post-humanist grinderm ovementa dvocating the use of DIY implants to augment the human body to at ranshuman state. [1][2][3][4][5][6][7][8][9][10][11][12][13].T he focus of the current state of the mainstreama rt rests in augmenting the body with ar ange of relatively simplistica rtificial sensors such as temperature,a ccelerometers for posture and motion, electrocardiology,a nd basic chemical sensors sucha sg lucose monitors.I nf act the body is already at reasure-trove of informationa nd integrated sensor systems that are waitingt ob et apped by the next generation of wearable sensor devices.T he human brain like am odern computer or smartphone,c an process thousands of signals from various inputs in an instant. These primary senses were first definedb yA ristotle in Sense and Sensebilia [14] however it was rather Plato in Theateus that first postulated to humansa nd animals being an etwork of "perceptions" when Socratess tatedt hat "The nameless ones are unlimited in number, but those which have been given names are extremely numerous" [15].J ust as am odern smartphone incorporates multiple sensors such as gyroscope, accelerometer, magnetometer and barometers in concert to accurately determine,a ggregate and presents implified locationa nd orientation information to the end user each of the five traditional perceptionsa re the result of multiple sensory functionsw ithin the human body.Fort he purpose of thisr eview we classify the multitude of sensory systems into the Aristotle model of five key senses used to gather information about the outside world. Theh uman body represents an immense source of data collection aggregation and archiving relating to surroundings,b iochemical and temporal processes that allow the brain to understand the environment and its effecto n the body in real time.T he potential to access such ah uge reservoir of data that can be captured from existing bodily sensor systems is the next greatest challengei n sensor development. Rather than develop ever more complicated sensor devices the biggest challenge is how to interface with the existing bodily data streams and harvestt his information to aid in diagnostics,h ealth and wellbeing.Between detectiona nd conscious sensationt herei so ne more essential step that holds the key to accessing the human big data set:d igitalization. In computer terms this is what happens between the first tap of ak ey on ak eyboard and its visualization on the computers creen.W ith computers the processi sr elatively simple,p ushingakey simply closes ac ircuit generating ac urrentt hat travels to the processing unit, where its unique pattern is decoded and translated to the character [16].Inthe b...

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Section: Visionmentioning

confidence: 99%

Section: Visionmentioning

confidence: 99%

Section: Visionmentioning

confidence: 99%

Section: Bacteriorhodopsinmentioning

confidence: 99%

Section: Special Issuementioning

confidence: 99%

See 3 more Smart Citations

Sensor Devices Inspired by the Five Senses: A Review

Svechtarova¹,

Buzzacchera²,

Toebes³

et al. 2016

Electroanalysis

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Fabrication of an optically driven pH gradient generator based on self-assembled proton pumps

Al-Aribe

Knopf

Bassi

2011

Microfluid Nanofluid

Self Cite

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Optically manipulating the local pH of a target solution in a microchannel, or reservoir, provides a mechanism for activating and controlling a variety of biological and chemical processes on Lab-on-a-Chip (LOC) devices and micro-total analysis systems (l-TAS). A microscale pH gradient generator that exploits the lightactivated molecular proton pumps found in the purple membranes (PM) of bacteriorhodopsin is described in this paper. The photo-electro-chemical transducer is an ultrathin layer (*13 nm) of oriented PM patches self-assembled on an Au-coated porous substrate. A biotin labeling and streptavidin molecular recognition technique is used to ensure that the extracellular side of all PM patches is attached to the porous substrate enabling unidirectional and efficient transport of ions across the transducer surface. The photo-induced proton pumps generate a flow of ions that produce a measurable change in pH between the separated solutions. The self-assembly procedure is experimentally quantified based on the capacitance characteristics of the bR membranes. The investigation confirms that the transducer is covered with the bR proton pumps at a mass density of 2.33 ng/cm 2 . Experimental tests also show that the proposed transducer can repeatedly generate pH gradients as high as 0.42 and absolute voltage differences as high as 25 mV when illuminated by an 18 mW, 568 nm light source. Furthermore, the DpH is observed to be nonlinear with respect to light intensity and exposure time. The DpH of the target solution is sufficient to cause a phenolphthalein indicator dye to change color or an ionic hydrogel micro-valve to expand.

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