Chain stiffness boosts active nanoparticle transport in polymer networks

Recent advances in technologies such as nanomanufacturing and nanorobotics have opened new pathways for the design of active nanoparticles (NPs) capable of penetrating biolayers for biomedical applications, e.g., for drug delivery. The coupling and feedback between active NP motility (with large stochastic increments relative to passive NPs) and the induced nonequilibrium deformation and relaxation responses of the polymer network, spanning scales from the NP to the local structure of the network, remain to be clarified. Using molecular dynamics simulations, combined with a Rouse mode analysis of network chains and position and velocity autocorrelation functions of the NPs, we demonstrate that the mobility of active NPs within cross-linked, concentrated polymer networks is a monotonically increasing function of chain stiffness, contrary to passive NPs, for which chain stiffness suppresses mobility. In flexible networks, active NPs exhibit a behavior similar to passive NPs, with a boost in mobility proportional to the self-propulsion force. These results are suggestive of design strategies for active NP penetration of stiff biopolymer matrices.

Automated summary

Recent advancements in nanotechnology have allowed for the design of active nanoparticles capable of penetrating biolayers for biomedical applications like drug delivery. The interactions between active nanoparticle motility and polymer networks at different scales remain unclear. Research using molecular dynamics simulations demonstrated that in cross-linked, concentrated polymer networks, the mobility of active nanoparticles increases with chain stiffness, unlike passive nanoparticles. In flexible networks, active nanoparticles exhibit behavior similar to passive nanoparticles, with increased mobility proportional to the self-propulsion force. These findings suggest potential design strategies for active nanoparticles to penetrate stiff biopolymer matrices.