PEGylation of zinc nanoparticles amplifies their ability to enhance olfactory responses to odorant

Published

December 20, 2017

Author(s)

Melissa Singletary, Samantha Hagerty, Shinichiro Muramoto, Yasmine Daniels, William A. MacCrehan, Gheorghe Stan, June W. Lau, Oleg Pustovyy, Ludmila Globa, Edward E. Morrison, Iryna Sorokulova, Vitaly Vodyanoy

Abstract

Responses of olfactory sensory neurons to odorants are intensely enhanced with the addition of small endogenous and engineered zinc nanoparticles, as shown by physiological experiments. The highest enhancement was recorded with 1.2 nm non-oxidized zinc nanoparticles and the oxidation of these nanoparticles inhibited the enhancement. Therefore an evaluation of stability and method of improvement are necessary. Zinc nanoparticles were produced from bulk metal rods by an underwater high-voltage discharge method. The nanoparticles were covered with 1000 g/mol or 400 g/mole molecular weight polyethylene glycol (PEG). Non-PEGylated and PEGylated zinc nanoparticles were tested by electroolfactogram with isolated rat olfactory epithelium and odorant responses evoked by the mixture of ethyl butyrate, eugenol, and (+) and (-) carvone. The functional and morphological stability of the zinc nanoparticles were evaluated over 317 days under storage at 278 K (5 oC). To stimulate accelerated aging, the stability of the nanoparticle were evaluated at 303 K (30 oC) and 323 K (50 oC). The particles were analyzed by x-ray photoelectron spectroscopy, transmission electron microscopy, atomic force microscopy, and the laser Doppler velocimetry. Both PEGylated nanoparticles had a crystalline zinc core, and varied in the degree of oxidation. Initially, EOG enhancement was similar across nanoparticles, but following 317 days of storage, ZnPEG400 provided the highest enhancement followed by zinc, and ZnPEG1000. These results indicate that ZnPEG400 is capable of maintaining the olfactory enhancement function of zinc nanoparticles with physiologically consistent stability over 300 days, providing a potential for future applications in olfaction, detection, and medicine.

Citation

ACS Nano

Pub Type

Journals

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Keywords

Olfaction, polyethylene glycol, stabilization, receptors, oxidation, electroolfactogram

Citation

Singletary, M. , Hagerty, S. , Muramoto, S. , Daniels, Y. , MacCrehan, W. , Stan, G. , Lau, J. , Pustovyy, O. , Globa, L. , Morrison, E. , Sorokulova, I. and Vodyanoy, V. (2017), PEGylation of zinc nanoparticles amplifies their ability to enhance olfactory responses to odorant, ACS Nano, [online], https://doi.org/10.1371/journal.pone.0189273 (Accessed April 25, 2024)