Scaffold Diffusion & Stiffness Match Lab

Scaffold material

Diffusion coefficient D 0.40

Degradation rate ×k₀ 1.0×

Applied strain ε 0%

Elapsed time

0.0 d

Remaining mass

100%

Stress σ = E(M)·ε

0 kPa

Mechanical match to tissue

—

How it works

A bioresorbable scaffold sits at the centre of a tissue volume. Three coupled real processes run every frame:

∂C/∂t = D∇²C          (drug/by-product diffusion, solved explicitly on a 9³ grid)
dM/dt = -kM  →  M(t)=M₀e^(-kt)   (first-order bulk-erosion mass loss)
σ = E(M)·ε,   E(M) = E₀·(M/M₀)^2.5   (stiffness, applied Hooke's law)

Diffusion coefficient D — how fast dissolved drug/degradation by-products spread from the scaffold into the surrounding grid (glowing = high local concentration). Solved with an explicit finite-difference Laplacian each step, not a fake particle spray.
Degradation rate ×k₀ — multiplies the material's base hydrolysis constant k₀. Remaining mass follows the exact first-order solution M(t)=M₀e^(−kt), the standard simplified model for bulk-eroding polymers like PLGA.
Applied strain ε — a mechanical pull/compression test. Stress is computed from Hooke's law σ=E·ε using the scaffold's *current* modulus, which falls faster than mass (exponent 2.5) because load-bearing struts lose percolating connectivity before the material fully dissolves.
Material — switches base modulus E₀, base degradation rate k₀ and the target modulus band for a realistic tissue interface: collagen↔soft tissue, PLGA↔trabecular bone, PLGA-collagen hybrid↔cartilage.

"Mechanical match" turns green while the current modulus stays inside the tissue's target band — the real mechanical-compatibility problem implant designers solve: too stiff and the scaffold stress-shields the tissue, too soft (post-degradation) and it can no longer bear load.

Scaffold core Low concentration High concentration

Interface: soft tissue / dermis

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