A method to measure pH inside mesoporous particles using protein-bound SNARF1 fluorescent probe
Journal article, 2013

We use fluorescence spectroscopy to measure the pH sensed by proteins which are immobilized in mesoporous silica particles by covalently attaching the pH-probe SNARF1 to the proteins. In contrast to previous attempts where pH-probes were attached to the pore surface, the present approach allows the pH to be measured without altering the properties of the silica material. When the particles are suspended in aqueous solutions of various pH the emission spectra of the labeled proteins indicate an environment inside the pores which is closer to neutral compared to the bulk solution. In a 1-butanol/water mixture (92.5/7.5%) the emission spectra of the immobilized proteins report a pH-behavior typical of the aqueous suspensions, in contrast to the blue-shifted emission spectrum of the protein in the outside organic solvent. This observation shows that the immobilized proteins experience an aqueous pore environment even though the surrounding solution is poor in water. The spectra of SNARF1-labeled bovine serum albumin and feruloyl esterase generated similar results suggesting that the method can be applied to different types of proteins. Taken together the results show that spectroscopic probes carried by immobilized macromolecules can be used to characterize the environment inside mesoporous particles without perturbing the properties of the material.

Fluorescent probe

Mesoporous materials

Protein labeling

pH measurement

Author

Christian Thörn

Chalmers, Chemical and Biological Engineering, Industrial biotechnology

Nils Carlsson

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Hanna Gustafsson

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

SuMo Biomaterials

Krister Holmberg

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Björn Åkerman

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Lisbeth Olsson

Chalmers, Chemical and Biological Engineering, Industrial biotechnology

Microporous and Mesoporous Materials

1387-1811 (ISSN)

Vol. 165 240-246

Subject Categories

Physical Chemistry

Analytical Chemistry

Biocatalysis and Enzyme Technology

Areas of Advance

Life Science Engineering (2010-2018)

Materials Science

DOI

10.1016/j.micromeso.2012.08.028

More information

Created

10/7/2017