Distribution of PEG-coated hollow polyelectrolyte microcapsules after introduction into the circulatory system and muscles of zebrafish

Ekaterina Borvinskaya; Anton Gurkov; Ekaterina Shchapova; Boris Baduev; Igor Meglinski; Maxim Timofeyev

doi:10.1242/bio.030015

Distribution of PEG-coated hollow polyelectrolyte microcapsules after introduction into the circulatory system and muscles of zebrafish

Biol Open. 2018 Jan 5;7(1):bio030015. doi: 10.1242/bio.030015.

Authors

Ekaterina Borvinskaya^{1

2}, Anton Gurkov^{1

3}, Ekaterina Shchapova¹, Boris Baduev^{1

3}, Igor Meglinski^{1

4}, Maxim Timofeyev⁵

Affiliations

¹ Institute of Biology at Irkutsk State University, Irkutsk 664003, Russia.
² Institute of Biology at Karelian Research Centre of Russian Academy of Sciences, Petrozavodsk 185035, Russia.
³ Baikal Research Centre, Irkutsk 664003, Russia.
⁴ University of Oulu, Optoelectronics and Measurement Techniques Laboratory, Oulu 90570, Finland.
⁵ Institute of Biology at Irkutsk State University, Irkutsk 664003, Russia m.a.timofeyev@gmail.com.

Abstract

The use of polyelectrolyte multilayer microcapsules as carriers for fluorescent molecular probes is a prospective technique for monitoring the physiological characteristics of animal vasculature and interstitial environment in vivo Polyelectrolyte microcapsules have many features that favor their use as implantable carriers of optical sensors, but little information is available on their interactions with complex living tissues, distribution or residence time following different routes of administration in the body of vertebrates. Using the common fish model, the zebrafish Danio rerio, we studied in vivo the distribution of non-biodegradable microcapsules covered with polyethylene glycol (PEG) over time in the adults and evaluated potential side effects of their delivery into the fish bloodstream and muscles. Fluorescent microcapsules administered into the bloodstream and interstitially (in concentrations that were sufficient for visualization and spectral signal recording) both showed negligible acute toxicity to the fishes during three weeks of observation. The distribution pattern of microcapsules delivered into the bloodstream was stable for at least one week, with microcapsules prevalent in capillaries-rich organs. However, after intramuscular injection, the phagocytosis of the microcapsules by immune cells was manifested, indicating considerable immunogenicity of the microcapsules despite PEG coverage. The long-term negative effects of chronic inflammation were also investigated in fish muscles by histological analysis.

Keywords: Fluorescent probes; In vivo sensing; Layer-by-layer; Microencapsulated biomarkers.