Photo-Magnetically Powered Spiky Nanomachines with Thermal Control of Viscosity for Enhanced Cancer Mechanotherapy.

Nanomachines with active propulsion have emerged as an intelligent platform for targeted cancer therapy. Achieving an efficient locomotion performance using an external energy conversion is a key requirement in the design of nanomachines. In this study, inspired by diverse spiky structures in nature, we proposed a photo-magnetically powered nanomachine (PMN) with a spiky surface and thermal-dependent viscosity tunability to facilitate mechanical motion in lysosomes for cancer mechanotherapy. The hybrid nanomachine was integrated with magnetic nanoparticles as the core and covered with gold nanotips. The physical simulations and experimental results proved that the spiky structure endows nanomachines with an obvious photo-magnetic coupling effect in the NIR-II region through the alignment and orienting movement of plasmons on the gold tips. Using a coupling-enhanced magnetic field, PMNs are efficiently assembled into chain-like structures to further elevate energy conversion efficiency. Notably, PMNs with the thermal control of viscosity were efficiently propelled under simultaneously-applied dual external energy sources in cell lysosomes. Enhanced mechanical destruction of cancer cells via PMNs was confirmed both in vitro and in vivo under photo-magnetic treatment. This study provides a new direction for designing integrated nanomachines with active adaptability to physiological environments for cancer treatment. This article is protected by copyright. All rights reserved.