A silica nanoparticle of radius diffuses in a buffer at ( ).

PHYSICS · Multi-part · Fermi University Physics · Biophysics & Medical Physics · Physical foundations of the living cell · Physical foundations of the living cell

Life at Thermal Energy, Ch Random walks, diffusion and the crowded cell

Problem

A silica nanoparticle of radius a=25 nma = 25\,\mathrm{nm} diffuses in a buffer at 25∘C25^\circ\mathrm{C} (η=0.89 mPa s\eta = 0.89\,\mathrm{mPa\,s}). ((a)) Predict its diffusion coefficient DD using the Stokes-Einstein relation. ((b)) Predict the time for the nanoparticle to diffuse a distance of 3.0 μm3.0\,\mathrm{\mu m} through the buffer, treating the crossing as one-dimensional. ((c)) Predict the new time if the distance to be crossed triples to 9.0 μm9.0\,\mathrm{\mu m}, without recomputing DD.

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