How can you make plaster for rats? - briefly
Mix plaster of Paris with water in roughly a 2:1 weight ratio, stir to a smooth consistency, pour into a mold sized for a small rodent, and let it cure completely. Rinse the hardened piece and smooth any sharp edges before handling.
How can you make plaster for rats? - in detail
To create a plaster formulation that can be safely applied to laboratory rats, follow a precise protocol that addresses material selection, preparation, sterilization, and handling.
Begin with a powder base that combines gypsum (calcium sulfate dihydrate) with a low‑density filler such as powdered cellulose. A typical ratio is 80 % gypsum to 20 % cellulose by weight. The filler reduces brittleness and improves adhesion to soft tissue. Add a small percentage (1–2 %) of a non‑ionic surfactant, for example polysorbate 80, to enhance wetting of the animal’s skin.
Measure the dry components on an analytical balance, then transfer them to a sterile mixing vessel. Introduce sterile distilled water at a volume equal to 0.5 times the weight of the dry mix (e.g., 5 g of powder requires 2.5 mL of water). Stir with a sterile, magnetic stir bar at 300 rpm for 30 seconds until a homogenous, smooth paste forms. Avoid air bubbles; a brief vacuum degassing step (30 seconds at 200 mbar) can be employed if necessary.
Before use, pass the prepared plaster through a 0.22 µm filter to remove potential contaminants. Store the filtered suspension in a sealed, sterile container at 4 °C and use within 2 hours to prevent premature setting.
Application requires a miniature, sterile applicator (e.g., a 0.5 mm diameter syringe). Position the rat under light anesthesia to minimize movement. Apply a thin layer (≈0.2 mm) of plaster directly onto the target area, ensuring coverage without excess bulk. The material begins to set within 2–3 minutes at ambient temperature (22–24 °C). Allow a total curing time of 10 minutes before the animal regains full mobility.
After the plaster has hardened, inspect for cracks or gaps. If needed, reinforce edges with a second, thinner coating applied in the same manner. Dispose of used materials according to biohazard protocols.
Key considerations: