# DIY Cell Preservation Options (Without -80°C Freezer)

Practical options for backing up relatively non-mutated cells, ranked by complexity/cost:

## 1. Commercial Cell Banking Services
- Companies: Acorn Biolabs, StemSave, etc.
- Process: Simple cheek swab or hair sample kit
- Cost: ~$1k-2k upfront + $190-300/year storage
- Pros: Professional GMP processing, vapor-phase LN₂ storage
- Cons: Trust external facility for decades

## 2. Household Dry Ice Method (-78°C)
- Equipment: Small dry ice maker, 2L Dewar or cooler
- Cost: $10-15/week for 5kg dry ice refills
- Method: DMSO + serum in cryovials → slow freeze → dry ice storage
- Viability: >70% for skin fibroblasts after 6 months (Grein et al. 2022)
- Cons: Temperature drift as CO₂ sublimes, limited long-term viability

## 3. Freeze-Drying for DNA Only
- Goal: Genetic snapshot rather than live cells
- Process: Skin biopsy → ethanol treatment → freeze-dry with vacuum pump
- Equipment: <$150 vacuum pump + desiccant chamber
- Pros: DNA recoverable decades later (Kriek et al. 2021)
- Cons: No live cells, nucleic acids only

## 4. DIY -20°C with Phase-Change
- Method: Earth cooling + phase-change coolants in insulated container
- Temperature: Maintains -8 to -12°C continuously
- Use case: Short-term storage (month-long viability)

## Recommendations
- **Long-term archive**: Option 1 (commercial) + Option 3 (backup)
- **Budget hack**: Option 2 with dry ice maintenance
- **DNA-only needs**: Skip to Option 3

Each approach has trade-offs between cost, complexity, and preservation quality.