CellSplit is a browser-based calculator for routine cell culture maintenance. It covers the two calculations performed at every passage: converting a Neubauer chamber count into viable cell density, and computing the inoculum volume needed to seed the next flask at a target density.
Both modules are linked — the viable concentration calculated in Module 1 is transferred automatically to Module 2, eliminating transcription between steps. The app runs entirely in the browser, installs as a PWA for offline use inside the biosafety cabinet, and requires no setup.
Cell culture passaging involves repetitive manual arithmetic done under time pressure, often inside a biosafety cabinet without access to a computer. Without a dedicated tool:
- Concentration calculations are done by hand or on scratch paper, introducing transcription errors
- The inoculum volume must be computed separately, from values just written down
- No feedback is given when the cell count falls outside a statistically reliable range
CellSplit removes all three problems. It validates the count range, computes both outputs in one step, and carries the result forward automatically.
Enter the number of live and dead cells counted, the number of squares used, and the dilution factor. CellSplit returns the viable cell concentration (×10⁶ cells/mL), the viability (%), and a count diagnostic.
| Diagnostic | Criterion |
|---|---|
| Low | Total cells < squares × 10 |
| Optimal | squares × 10 ≤ total ≤ squares × 50 |
| High | Total cells > squares × 50 |
The optimal window (~10–50 events per square) avoids both sampling noise from sparse counts and systematic undercounting from cell overlap.
Formulas
The factor 10,000 comes from the Neubauer chamber geometry: one large square covers 1 mm² at 0.1 mm depth = 10⁻⁴ mL, so multiplying by its reciprocal converts count per square into cells per mL.
The viable concentration from Module 1 is pre-filled. Set the target culture volume and target seeding density; CellSplit returns the inoculum volume and the volume of fresh medium required.
C₁ must exceed C₂. The app returns an error if the target density is higher than the current culture density.
| Automatic data link | Viable concentration transfers from Module 1 to Module 2 without manual entry |
| Count diagnostics | Visual badge flags low, optimal, or high cell counts per square |
| Offline-first PWA | Service Worker caches all assets; works without internet after first load |
| Bilingual UI | Full Spanish / English interface, persisted across sessions |
| Dark mode | System-level dark mode — high contrast for low-light microscope rooms |
| No installation | Opens instantly in any modern browser; installable on Android, iOS, and desktop |
Frontend
Deployment
Fully static — no backend, no framework, no build step. All computation runs client-side in vanilla JavaScript.
CellSplit/
├── index.html ← markup only
├── manifest.json ← PWA manifest
├── sw.js ← Service Worker (cache-first, offline support)
├── icon-192.png
├── icon-512.png
└── src/
├── css/
│ └── app.css ← all styles (CSS variables, dark mode, glassmorphism)
└── js/
├── i18n.js ← translation strings (ES / EN)
└── app.js ← all application logic
Emiliano Balderas Ramírez Bioengineer · PhD Candidate in Biochemical Sciences Instituto de Biotecnología (IBt), UNAM
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