title: A protein-dye hybrid system as a narrow range tunable intracellular pH sensor.
abstract: Accurate monitoring of pH variations inside cells is important for the early diagnosis of diseases such as cancer. Even though a variety of different pH sensors are available, construction of a custom-made sensor array for measuring minute variations in a narrow biological pH window, using easily available constituents, is a challenge. Here we report two-component hybrid sensors derived from a protein and organic dye nanoparticles whose sensitivity range can be tuned by choosing different ratios of the components, to monitor the minute pH variations in a given system. The dye interacts noncovalently with the protein at lower pH and covalently at higher pH, triggering two distinguishable fluorescent signals at 700 and 480 nm, respectively. The pH sensitivity region of the probe can be tuned for every unit of the pH window resulting in custom-made pH sensors. These narrow range tunable pH sensors have been used to monitor pH variations in HeLa cells using the fluorescence imaging technique.
authors.affiliation: Chemical Sciences and Technology Division , Academy of Scientific and Innovative Research (AcSIR) , CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST) , Thiruvananthapuram 695019 , India . Email: ajayaghosh@niist.res.in.
authors.forename: Palapuravan
authors.initials: P
authors.lastname: Anees
authors.affiliation: Chemical Sciences and Technology Division , Academy of Scientific and Innovative Research (AcSIR) , CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST) , Thiruvananthapuram 695019 , India . Email: ajayaghosh@niist.res.in.
authors.forename: Karivachery V
authors.initials: KV
authors.lastname: Sudheesh
authors.affiliation: Agroprocessing and Natural Products Division , Academy of Scientific and Innovative Research (AcSIR) , CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST) , Thiruvananthapuram , 695019 , India.
authors.forename: Purushothaman
authors.initials: P
authors.lastname: Jayamurthy
authors.affiliation: Molecular Neurobiology Division , Rajiv Gandhi Centre for Biotechnology (RGCB) , Thiruvananthapuram 695 014 , India.
authors.forename: Arunkumar R
authors.initials: AR
authors.lastname: Chandrika
authors.affiliation: Molecular Neurobiology Division , Rajiv Gandhi Centre for Biotechnology (RGCB) , Thiruvananthapuram 695 014 , India.
authors.forename: Ramakrishnapillai V
authors.initials: RV
authors.lastname: Omkumar
authors.affiliation: Chemical Sciences and Technology Division , Academy of Scientific and Innovative Research (AcSIR) , CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST) , Thiruvananthapuram 695019 , India . Email: ajayaghosh@niist.res.in.
authors.forename: Ayyappanpillai
authors.initials: A
authors.lastname: Ajayaghosh