TissueDB/Materials/Agar
CC BY-SA 2.0 by Fred Miller, U of A System Division of Agriculture
Agar (also known as agar-agar, kanten, E406) is a gel-forming substance derived from red seaweed (algae). It is widely used in medical simulation for tissue phantom construction. Agar does not require refrigeration once set and maintains its structure at temperatures up to 85 °C, making it suitable for resource-limited and austere environments.
Tissues
| Tissue | Visual | Tactile | Simulator | Notes |
|---|---|---|---|---|
| Vessels (vascular access) | Yes | Yes | 5% agar + 3% silica dioxide, set around silicone tubing. | |
| Brain / Muscle | Yes | Partial | 2% agar + 2% silica dioxide + 40% evaporated milk. | |
| Breast lesions | Yes | Partial | Black-ink agar + embedded green olives, poured into breast-shaped mold. | |
| Liver | Partial | Partial | 4–5% agar + albumin, molded to liver shape. |
Troubleshooting
- Concentrations below 2% — Gels too soft and tear unrealistically during procedures, teaching incorrect force calibration.
- Dehydrated gels — Cracked surfaces create unrealistic needle resistance; use fresh-prepared gels only.
- Overheating (>100 °C) — Agar degrades and loses gel strength; boil briefly then reduce heat to 80–85 °C for setting.
- Procedures requiring elastic recoil — Agar is brittle and does not simulate tissue elasticity. Use gelatin or hybrid formulations with konjac instead.
Alternatives
| Alternative | Best For | Trade-offs |
|---|---|---|
| Gelatin Mix | Repeated needle insertion (self-healing properties) | Animal-derived; requires refrigeration |
| Konjac | Hybrid phantoms with elastic recoil | Less widely available; different gelation kinetics |
| Carrageenan | Hybrid phantoms combined with agar | Different melting behaviour requires adjusted protocols |
References
[edit source]
Overview
[edit source]Agar is a plant-derived gelling agent from red seaweed (Rhodophyta family). Supplied as a solid powder; becomes gel when heated and cooled. Gel melting point approximately 80–90 °C (varies by concentration and purity). Thermal stability maintains gel structure up to 85 °C. Fully biodegradable and compostable. Cost approximately USD 8–25 per pound from grocery stores, specialty ingredient suppliers, or Asian grocery wholesalers (lower end reflects bulk or Asian grocery pricing). Indefinite shelf life in powder form if kept dry.
Synonyms
[edit source]Common names: Agar-agar, Kanten, E406, Japanese isinglass
Forms: Agar powder, agar flakes, agar strips, agar gel
Regional terms: Agar-agar (Malay/Indonesian), Kanten (Japanese), Gelosa (Portuguese/Spanish), China grass (Indian English)
Shelf Life & Storage
| Temp Range | Humidity | Surface Reuse | Shelf Life | Spoilage |
|---|---|---|---|---|
| Room temperature (no refrigeration needed once set) | Dry (<60%) | Single use (phantoms); reusable with remelting | Indefinite (powder form, keep dry) | Mold growth if stored wet; dehydration cracking |
Clinical Context for Simulation
[edit source]Processing & Preparation
[edit source]Safety Considerations
[edit source]Related Materials
[edit source]
| Authors | Arturopelayo |
|---|---|
| License | CC-BY-SA-4.0 |
| Cite as | Arturopelayo (2026). "TissueDB/Materials/Agar". Appropedia. Retrieved June 4, 2026. |