What should be used to coat a tick? - briefly
Use fine‑pointed tweezers to grasp the tick as close to the skin as possible and pull upward with steady pressure. Do not apply any coating or substance to the parasite.
What should be used to coat a tick? - in detail
When preparing a tick for microscopic examination, the coating material must preserve morphology, prevent distortion, and allow clear visualization of surface structures. The most reliable substances are:
- Acrylic mounting media (e.g., Permount, DPX). Provide a transparent, durable layer that hardens quickly and resists yellowing.
- Synthetic resins such as Canada balsam or Euparal. Offer high refractive index and long‑term stability, suitable for permanent slides.
- Silicone‑based polymers (e.g., ClearMount). Deliver flexibility, reducing stress on delicate cuticular features.
- Water‑soluble gels (e.g., gelatin, agarose). Useful for temporary mounts where re‑examination is anticipated; they maintain hydration but are less durable.
Preparation steps:
- Fixation – immerse the specimen in 70 % ethanol or a buffered formalin solution for 10–15 minutes to halt decomposition.
- Rinsing – wash with distilled water to remove excess fixative, preventing interference with the coating.
- Dehydration – pass through graded ethanol series (70 %, 80 %, 95 %, 100 %) to eliminate moisture that could cause clouding.
- Clearing – treat with a clearing agent such as xylene or clove oil to improve penetration of the coating medium.
- Application – place a drop of the chosen mounting medium on a clean slide, position the tick, and gently cover with a cover slip, avoiding air bubbles.
- Curing – allow the medium to polymerize according to manufacturer instructions; typically 24 hours for resins, 1–2 hours for acrylics.
Considerations for selection:
- Refractive index – match the medium to the objective lens to maximize contrast.
- Chemical compatibility – avoid solvents that dissolve the coating; for example, oil‑based resins are unsuitable with alcohol‑based fixatives.
- Longevity – permanent resins preserve specimens for years, while aqueous gels are limited to short‑term studies.
- Safety – handle volatile solvents (xylene, toluene) in a fume hood and use protective gloves.
By following these protocols and choosing an appropriate mounting substance, the tick’s external morphology remains intact, enabling accurate identification and detailed morphological analysis.