Cargo‐Towing Fuel‐Free Magnetic Nanoswimmers for Targeted Drug Delivery

Abstract

Fuel‐free nanomotors are essential for future in‐vivo biomedical transport and drug‐delivery applications. Herein, the first example of directed delivery of drug‐loaded magnetic polymeric particles using magnetically driven flexible nanoswimmers is described. It is demonstrated that flexible magnetic nickel–silver nanoswimmers (5–6 μm in length and 200 nm in diameter) are able to transport micrometer particles at high speeds of more than 10 μm s−1 (more than 0.2 body lengths per revolution in dimensionless speed). The fundamental mechanism of the cargo‐towing ability of these magnetic (fuel‐free) nanowire motors is modelled, and the hydrodynamic features of these cargo‐loaded motors discussed. The effect of the cargo size on swimming performance is evaluated experimentally and compared to a theoretical model, emphasizing the interplay between hydrodynamic drag forces and boundary actuation. The latter leads to an unusual increase of the propulsion speed at an intermediate particle size. Potential applications of these cargo‐towing nanoswimmers are demonstrated by using the directed delivery of drug‐loaded microparticles to HeLa cancer cells in biological media. Transport of the drug carriers through a microchannel from the pick‐up zone to the release microwell is further illustrated. It is expected that magnetically driven nanoswimmers will provide a new approach for the rapid delivery of target‐specific drug carriers to predetermined destinations.

Electrodeposited conductive polymers for controlled drug release: polypyrrole

“…7 Catalytic nanomotors for a self-powered drug delivery system. After Pumera [71] and Sundararajan et al [89] still questionable because they are usually designed from a non-degradable material having the potential to generate toxic species such as nickel, chromium and silver ions [77,97,98]. Biocompatible and biodegradable materials instead of the non-degradable metals such as Pt are commonly used to fabricate these motors.…”

The efficiency of self-phoretic propulsion mechanisms with surface reaction heterogeneity

“…These systems have been connected to a number of potential applications, including: cancer treatment [8,9], drug delivery [10][11][12][13], soil remediation [14], and microfluidic mixing [15][16][17][18]. In addition, swimmers show promise as model systems for out-of-equilibrium phenomena [19,20], for which a thermodynamic description is still in its infancy when compared to the fully established formalism of statistical physics.…”

On the motion of linked spheres in a Stokes flow

“…Furthermore, as the actuation of the swimmer is controlled completely by the interaction of hard magnets and an external field, it will be possible to reproduce the swimmer at the micro-scale. Such a synthetic swimmer has potential for implementation in in vivo drug delivery (Gao et al 2012) and as pumps in microfluidic devices (Leoni et al 2008).…”