Wet mount slide preparations, while useful for viewing live specimens in their natural state, have several disadvantages:
- Specimen Movement: Live organisms can move freely in the liquid medium, making it difficult to keep them in focus or to capture clear images and detailed observations. This mobility can complicate drawing or photographing specimens
- Drying Out: The liquid in wet mounts evaporates quickly, especially under the heat of microscope lamps, causing the specimen to dry out and potentially die or change shape. This limits the viewing time and can distort observations
- Air Bubbles: Improper technique can trap air bubbles under the coverslip, obstructing the view and creating artifacts that interfere with accurate observation
- Pressure Damage: Using too little liquid can cause the coverslip to press down too hard, crushing or distorting delicate specimens. Conversely, too much liquid can cause the coverslip to float and vibrate, making steady observation difficult
- Limited Storage: Wet mounts are temporary; they cannot be stored for long periods because the liquid evaporates and specimens degrade, unlike permanent mounts that use solidifying media
- Focus Challenges: Specimens may move vertically in the liquid, moving in and out of the focal plane, which complicates maintaining a sharp image
- Low Sensitivity for Some Applications: For certain diagnostic uses, wet mount microscopy has lower sensitivity compared to other methods like PCR, partly due to the small volume of liquid used and difficulty in detecting low concentrations of organisms
In summary, while wet mounts are excellent for observing live specimens and their natural behavior, their disadvantages include specimen mobility, rapid drying, air bubbles, potential specimen damage from pressure, difficulty in focusing, and lack of long-term storage capability
