Growth Factor Dose-Response Simulator (2D)

Delivery Mode

Bolus dose 40 ng/mL

Scaffold release half-life 4.0 hr

Simulation speed 1.0x

Live State

Subtherapeutic

GF concentration C

0.0 ng/mL

Sim. time

0.0 hr

Cell population N

Tumor-risk index

How it works

A growth factor released near a scaffold binds cell-surface receptors and drives proliferation through a saturating Hill-type dose-response, exactly as described for EGF/PDGF/TGF-β in regenerative medicine:

P(C) = Pmax · C^n / (Kd^n + C^n)      (Hill equation, n = 2)
dN/dt = P(C) · N · (1 − N/Ncap)        (logistic proliferation)
dC/dt = r(mode) − k·C,  k = ln(2)/t½   (release − first-order clearance)
dRisk/dt = g · max(0, C − Cthresh)     (excess-exposure accumulation,
                                        decays when C falls back under threshold)

Bolus / Sustained release — a bolus injects a pulse of growth factor that then decays exponentially with the scaffold's clearance half-life; sustained release instead adds a continuous infusion that settles near a steady state r/k.
Dose slider — sets the bolus peak (ng/mL) or the infusion rate (ng/mL·hr⁻¹).
Half-life slider — how fast the scaffold/tissue clears free growth factor; a short half-life needs a higher dose or repeated boluses to stay in the therapeutic window.
Simulation speed — scales how many simulated hours elapse per real second, so you can watch a slow sustained-release protocol play out quickly or a fast bolus decay in detail.
Subtherapeutic (C below ~½Kd) — proliferation signal too weak, regeneration stalls. Regenerative window (C between Kd and the tumor-risk threshold) — controlled, capacity-limited tissue growth. Hyperproliferative (C above threshold) — the logistic cap is overridden and cells proliferate uncontrolled, exactly the tumor-formation risk the article warns about.
The top-down cell map, the Hill dose-response curve and the concentration/risk strip chart all update from the same live state — drag inside the cell map to rotate the view, scroll to zoom.

This is the same concentration-control problem every real delivery method — direct injection, biomaterial encapsulation, or local gene therapy — has to solve: enough growth factor to regenerate tissue, not so much that signaling runs away.

Regenerating cell Hyperproliferative cell Growth-factor field

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