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

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.

Bioimaging Tools Based on Polyelectrolyte Microcapsules Encoded with Fluorescent Semiconductor Nanoparticles: Design and Characterization of the Fluorescent Properties

“…Being injected intravenously, microcapsules of this size cannot penetrate across blood–tissue barriers, which allows the transport and distribution of optically encoded microcapsules in the body to be traced [31, 32]. However, in localizations with an enhanced permeability of the blood vessel wall, e.g., in inflammation and tumor-growth areas, microcapsules can penetrate into the extravascular space, which is expected to ensure the imaging and monitoring of targeted delivery [33–36].

Fig.

…”

Plant-Derived Biomaterials: A Review of 3D Bioprinting and Biomedical Applications

“…Alginate has been used to enable modified/extended release of an active drug within the body (Tønnesen and Karlsen, 2002) and as a component in the construction of capsules used for cellencapsulation. For cytotherapy, combined with chitosan, the mixture demonstrates high cell viability (Correia et al, 2013) and may be also combined with calcium carbonate to selectively trap of molecules on hydrophilic domains, or polyethylene glycol to protect the microcapsules from acidic environments such as gastric acid (Borvinskaya et al, 2018;Ren et al, 2018). These properties have enabled composites of alginate to be trialed in the treatment of degenerative diseases such as osteoarthritis (Wang et al, 2011).…”

Application of PEG-Covered Non-Biodegradable Polyelectrolyte Microcapsules in the Crustacean Circulatory System on the Example of the Amphipod Eulimnogammarus verrucosus

“…The injection of microcapsules in the isotonic solution or saline alone revealed no effect on E. verrucosus survival in comparison to the parallel control group, without any injections, during six weeks (Figure 4). Similarly, no distinct effect of the same microcapsules was previously observed on the survival of the fish Danio rerio [21].…”

“…Despite the microcapsules being assembled of non-biodegradable polymers, they potentially could be decomposed to the individual polymers, for example, under extreme pH [38,39], which may be produced by the amphipod hemocytes [40] participating in the immune response. However, previous studies showed that cells of vertebrates seem to be unable to disintegrate the phagocytosed PAH/PSS-based microcapsules [21,41]. Additionally, the dissection of E. verrucosus after the six-week experiment showed plenty of intact fluorescent microcapsules around internal organs.…”

“…Fluorescent microscopy was performed in either the green channel (the peak excitation wavelength at 496 nm; long-pass emission filter from ~510 nm) or the red channel (the peak excitation wavelength at 546 nm; long-pass emission filter from ~585 nm). The parameters of the green channel were standard for visualization of FITC and similar dyes; the illumination conditions of the red channel were optimized to excite SNARF-1 in the used optical system [16,21]. Data analysis was performed using the Scilab package ().…”