Antifungal Membrane Attack Simulator (2D)

This 2D cross-section view puts a fungal membrane (rich in ergosterol) side by side with a human membrane (rich in cholesterol) and doses both with the same bulk concentration of a polyene antifungal. Individual drug molecules are simulated as discrete particles that diffuse across each membrane and bind sterol sites with a real affinity difference — much stronger for ergosterol than cholesterol. A pore only opens once a genuine cooperative threshold of simultaneously-bound molecules is counted within a local radius, reproducing the barrel-stave aggregation mechanism of real polyenes such as amphotericin B. Because the binding-affinity gap makes fungal sterol sites accumulate bound drug far faster, pore-formation events and K⁺ ion leakage occur much more often on the fungal side at identical concentration — the mechanistic basis of selective antifungal toxicity, which you can verify numerically with the built-in concentration sweep.