A novel approach to imaging engorged ticks: Micro-CT scanning of Ixodes ricinus fed on blood enriched with gold nanoparticles

Jaroslav Ondruš; František Hubatka; Pavel Kulich; Nikola Odehnalová; Vratislav Harabiš; Branislav Hesko; Oldřich Sychra; Pavel Široký; Jaroslav Turánek; Adam Novobilský

doi:10.1016/j.ttbdis.2020.101559

A novel approach to imaging engorged ticks: Micro-CT scanning of Ixodes ricinus fed on blood enriched with gold nanoparticles

Ticks Tick Borne Dis. 2021 Jan;12(1):101559. doi: 10.1016/j.ttbdis.2020.101559. Epub 2020 Sep 28.

Affiliations

¹ CEITEC - Central European Institute of Technology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic; Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic; Department of Pharmacology and Toxicology, Veterinary Research Institute, Hudcova 296/70, 621 00, Brno, Czech Republic. Electronic address: jaroslavondrus@seznam.cz.
² Department of Pharmacology and Toxicology, Veterinary Research Institute, Hudcova 296/70, 621 00, Brno, Czech Republic.
³ Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, 616 00, Brno, Czech Republic.
⁴ Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic.
⁵ CEITEC - Central European Institute of Technology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic; Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic.

PMID: 33137638
DOI: 10.1016/j.ttbdis.2020.101559

Abstract

Micro-computed tomography (micro-CT) is an exceptional imaging modality which is limited in visualizing soft biological tissues that need pre-examination contrasting steps, which can cause serious deformation to sizeable specimens like engorged ticks. The aim of this study was to develop a new technique to bypass these limitations and allow the imaging of fed ticks in their natural state. To accomplish this, adult Ixodes ricinus females were allowed to engorge in vitro on blood supplemented with PEGylated gold nanoparticles (PEG-AuNPs). In total, 73/120 females divided into 6 groups engorged on blood enriched with 0.07-2.16 mg PEG-AuNPs per ml of blood. No toxic effect was observed for any of the tested groups compared to the control group, in which 12/20 females engorged on clear blood. The ticks were scanned on a Bruker micro-CT SkyScan 1276. The mean radiodensity of the examined ticks exceeded 0 Hounsfield Units only in the case of the two groups with the highest concentration. The best contrast was observed in ticks engorged on blood with the highest tested concentration of 2.16 mg/mL PEG-AuNPs. In these ticks, the midgut and rectal sac were clearly visible. Also, the midgut lumen volume was computed from segmented image data. The reduction in midgut volume was documented during the egg development process. According to this pilot study, micro-CT of ticks engorged on blood supplemented with contrasting agents in vitro may reveal additional information regarding the engorged ticks' anatomy.

Keywords: Anatomy; Arthropods; Gold nanoparticles; In vitro feeding; Micro-computed tomography; Non-destructive visualization.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Blood
Feeding Behavior
Female
Gold*
Ixodes*
Metal Nanoparticles*
X-Ray Microtomography / methods*

Substances

Gold