title: Self-Assembled Fluorescent Bovine Serum Albumin Nanoprobes for Ratiometric pH Measurement inside Living Cells.
abstract: In this work, we demonstrated a new ratiometric method for the quantitative analysis of pH inside living cells. The structure of the nanosensor comprises a biofriendly fluorescent bovine serum albumin (BSA) matrix, acting as a pH probe, and pH-insensitive reference dye Alexa 594 enabling ratiometric quantitative pH measurement. The fluorescent BSA matrix was synthesized by cross-linking of the denatured BSA proteins in ethanol with glutaraldehyde. The size of the as-synthesized BSA nanoparticles can be readily manipulated from 30 to 90 nm, which exhibit decent fluorescence at the peak wavelength of 535 nm with a pH response range of 6-8. The potential of this pH sensor for intracellular pH monitoring was demonstrated inside living HeLa cells, whereby a significant change in fluorescence ratio was observed when the pH of the cell was switched from normal to acidic with anticancer drug treatment. The fast response of the nanosensor makes it a very powerful tool in monitoring the processes occurring within the cytosol.
authors.affiliation: Dynamic Optical Microscopic Imaging Laboratory, Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Ministry of Education, Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha, Hunan 410081, People's Republic of China.
authors.forename: Qiaoyu
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Dynamic Optical Microscopic Imaging Laboratory, Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Ministry of Education, Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha, Hunan 410081, People's Republic of China.
authors.forename: Zhongju
authors.initials: Z
authors.lastname: Ye
authors.affiliation: Dynamic Optical Microscopic Imaging Laboratory, Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Ministry of Education, Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha, Hunan 410081, People's Republic of China.
authors.forename: Meile
authors.initials: M
authors.lastname: Zhong
authors.affiliation: Dynamic Optical Microscopic Imaging Laboratory, Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Ministry of Education, Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha, Hunan 410081, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.affiliation: Key Laboratory of Theoretical Organic Chemistry and Function Molecule of Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology , Xiangtan, Hunan 411201, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Theoretical Organic Chemistry and Function Molecule of Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology , Xiangtan, Hunan 411201, People's Republic of China.
authors.forename: Rongjin
authors.initials: R
authors.lastname: Zeng
authors.affiliation: Dynamic Optical Microscopic Imaging Laboratory, Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Ministry of Education, Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha, Hunan 410081, People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Wei
authors.affiliation: Department of Chemistry, Hongkong Baptist University , Kowloon Tong, Hong Kong, People's Republic of China.
authors.forename: Hung-wing
authors.initials: HW
authors.lastname: Li
authors.affiliation: Dynamic Optical Microscopic Imaging Laboratory, Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Ministry of Education, Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha, Hunan 410081, People's Republic of China.
authors.forename: Lehui
authors.initials: L
authors.lastname: Xiao
mesh_terms: D002470:Cell Survival; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D012710:Serum Albumin, Bovine
keywords: cellular imaging; fluorescent nanoparticles; pH sensing; protein nanoparticles; ratiometric