Biodegradable Untethered Magnetic Hydrogel Milli‐Grippers. (15th September 2020)

• Record Type: Journal Article
• Authors: Goudu, Sandhya Rani; Yasa, Immihan Ceren; Hu, Xinghao; Ceylan, Hakan; Hu, Wenqi; Sitti, Metin
• Is Part Of: Advanced functional materials. Volume 30:Number 50(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-09-15
• Subjects: biocompatible -- biodegradable -- medical devices -- millirobot -- soft robot; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202004975
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Small‐scale magnetic soft‐bodied robots based on biocompatible and biodegradable materials are essential for their potential high‐impact minimally invasive medical applications inside the human body. Therefore, a strategy for fully biodegradable untethered soft millirobots with encoded 3D magnetic anisotropy for their static or dynamic shape programming is presented. Such a robot body is comprised of a porcine extracellular matrix‐derived collagen‐based hydrogel network with embedded superparamagnetic iron oxide nanoparticles (SPIONs). 3D magnetization programming inside the hydrogel body is achieved by directionally self‐assembled SPION chains using an external permanent magnet. As a proof‐of‐concept demonstration, a hydrogel milli‐gripper that can undergo flexible and reversible shape deformations inside glycerol and biologically relevant liquid media is presented. The gripper can perform cargo grabbing, transportation by rolling, and release by controlling magnetic field inputs. These milli‐grippers can be completely degraded by the matrix metalloproteinase‐2 enzyme in physiologically relevant concentrations. Furthermore, biocompatibility tests using human umbilical cord vein endothelial cells with the degradation products of the grippers demonstrate no acute toxicity. The approach offers a facile fabrication strategy for designing biocompatible and biodegradable soft robots using nanocomposite materials with programmable 3D magnetic anisotropy toward future medical applications. Abstract : A biodegradable magnetic milli‐gripper is developed by creating a 3D magnetic profile in a gelatin hydrogel matrix using directionally self‐assembled superparamagnetic iron oxide nanoparticle chains. It can undergo reversible shape deformations and perform cargo grasping and transportation tasks under controlled magnetic fields. The milli‐gripper can be completely degraded by the matrix metalloproteinase‐2 enzyme in physiologically relevant concentrations.