Towards hybrid microrobots using pH- and photo-responsive hydrogels for cancer targeting and drug delivery

Abstract

This work is towards targeted drug delivery using microrobots functionalized to navigate towards naturally occurring pH gradients caused by cancer cells, and to release a payload in response to a light stimulus. Stimuli-responsive microrobots for the localization of specific cell types and targeted drug delivery could provide a new and promising therapy to prevent and treat the spread of cancer. In this work, we present two novel biocompatible photoresists for the fabrication of hybrid microrobots using two-photon polymerization (TPP) for medical applications. One biomarker for cancerous cells is that they exhibit lower pH compared to surrounding healthy tissue. In this work, a pH-responsive resist was developed and demonstrated to automatically seek a low-pH solid in a microfluidic channel, simulating metastatic cells within a vessel. The second resist, a hydrogel-based photoresist, was created to contract in response to light. The two resists were combined together in a two-step printing process to create a microswimmer with potential for tumor localization and drug release capabilities in the human circulatory system.