Design, Synthesis and Evaluation of Near‐Infrared Fluorescent pH Indicators in a Physiologically Relevant Range.

2012 IEEE/RSJ International Conference on Intelligent Robots and Systems

Kariya

Nakamura

et al. 2012

In this paper, we proposed long-lifetime and high-sensitive measurement using fluorescent intensity by compensation of photo-bleaching with the difference compensation for cell measurement. Photo-bleaching of fluorescence is one of the most crucial factors to cause measurement error in physiological measurement. In our approach, difference of fluorescent intensity between imaging time is compensated using single exponential function to make the difference amount uniform in each imaging time. We evaluated the dependencies of measurable time and the sensitivity by fluorescent lifetime and the decay coefficient of fluorescent lifetime using numerical simulation. From these results, the proposed method has much higher sensitivity and longer measurable time against conventional compensation method of photo-bleaching. By using the proposed method, we demonstrate the photosynthesis activity of single Synechocystis sp. PCC 6803 in the micro chamber with gas barrier layer.

Section: Compensation Of Photo-bleaching Using Difference Compensamentioning

confidence: 99%

“…This method uses the environmental dependency of quantum yield of fluorescent indicators. By using this method, various parameters, such as temperature, pH, oxygen, calcium ion, are measured [9,10]. However, fluorescent intensity from the indicator decreases by photochemical destruction of the indicator during measurement [11].…”

Section: Introductionmentioning

confidence: 99%

Ultra long-lifetime and high-sensitive fluorescent measurement using difference compensation method for single cell analysis

2012 IEEE/RSJ International Conference on Intelligent Robots and Systems

Kariya

Nakamura

et al. 2012

“…Advances in the digital imaging technology, have now permitted the extension of fiber-optico fluorosensor techniques to two dimensions with high spatial resolution [8][9][10][11][12]. However, fluorescent methods have major problems with absorption with some molecules, quenching and photo-degradation.…”

Section: Introductionmentioning

confidence: 99%

Development of a pH indicator immobilized-gel-sheet for microenviroment analysis

Masuda

2009 International Symposium on Micro-NanoMechatronics and Human Science

Arai

et al. 2009

Detection of change in microenvironmental pH may be essential for analyzing biological processes, if transitory biodegradable scaffold materials are used for tissue engineering in bone regeneration. In this study, we created a pH indicator immobilized-gel-sheet for pH measurement. By using gel-sheet, we can investigate the local microenvironment of biodegradable materials, such as octacalcium phosphate (OCP), under the various protein adsorptions. The gel-sheet was made of a photocrosslinkable prepolymer solution (TUPR-5), which was easily immobilized by the method that the pH indicator is entrapped in a porous polymeric substrate. Bromothymol Blue (BTB) immobilized-gel-sheet was mounted in a biochip made of polydimethylsiloxane (PDMS) with a flow channel. The pH value was calculated by detecting the color changes, and presented as the pH distribution via a custom-made application. The pH sensing was carried out based on the surrounding color information of an OCP granule if incubated in culture medium. The gel-sheet detected the pH values of the condition around an OCP granule, showing the decrease from pH 7.8 to 8.8. As a whole, the proposed pH indicator is capable of providing pH level by high-spatial resolution.

“…Conventionally, fluorescence observation was the major approach for environmental measurements (Shinohara et al 2004;Nishimura et al 2005;Zhang and Achilefu 2005;Klauke et al 2006). On the pH measurement, a pH-sensing microscope has been developed (Nakao et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Functional gel-microbead manipulated by optical tweezers for local environment measurement in microchip

Fukuda

Arai

2009

Microfluid Nanofluid

A novel on-chip environment measurement with functional gel-microtool was developed. Environment measurement gel-microtool was fabricated by connecting the gel-microbeads impregnated with indicators in a microchip. In this artcle, Bromothymol blue (BTB) and Bromocresol green (BCG) were employed as pH indicators. BTB and BCG have the different indicator range. Rhodamine B is temperature sensitive fluorescent dye and is used for temperature measurement. Gel-microbead is made by salting-out of hydrophilic photo-crosslinkable resin and is manipulated by optical tweezers. Moreover, gel-microbead is polymerized by UV illumination and connected to other gel-microbead under an electrolyte solution. The connection of gel-microbeads is performed by contact of gel-microbeads under UV illumination. Environment measurement gel-microtool with an arbitrary shape is fabricated by connection of the gel-microtool impregnated with arbitrary indicator. Multiple environments measurement gel-microtool included with several indicators is realized by assembly of the gel-microbeads impregnated with different indicators. Environment measurement is performed by detecting the color and the fluorescence intensity of each gel-microbead. We succeeded in the on-chip fabrication of the environment measurement gel-microtools such as circular pH measurement gel-microtool and wide range pH measurement gelmicrotool in a microchip.