Programmable Anisotropic Hydrogels with Localized Photothermal/Magnetic Responsive Properties

Abstract

Programmable smart materials that can respond locally to specific stimuli hold great potential for many applications, but controllable fabrication of these materials remains challenging. This work reports the development of novel programmable anisotropic materials with both magnetic and photothermal stimuli‐responsiveness, which are fabricated by anchoring thermosensitive poly(N‐isopropyl acrylamide) (PNIPAm) and magnetic Fe3O4 nanoparticles on the surface of MoS2 nanosheets. Further embedding PNIPAm‐MoS2/Fe3O4 into 3D‐printed hydrogel cubes results in stimuli‐responsive building blocks, and the magnetic field can precisely control their orientation and near‐infrared (NIR) light absorbing property. Particularly, the variation of the orientation of MoS2/Fe3O4 block results in obvious changes of their photothermal efficiency and optical property. By exploiting the anisotropy of MoS2/Fe3O4 and their NIR light responsiveness, thermally‐induced phase transitions in individual 3D printed hydrogel building block can be locally controlled for magnetic field‐assisted programming a quick response (QR) code. Alternatively, fluorescent QR code with high contrast and security level can be achieved by photothermal‐induced release of fluorescent dyes. These 3D printed magnetically programmed hydrogels hold great potential for application in information storage, intelligent materials, and precise therapy.

Magnetically anisotropic hydrogels for tissue engineering

“…4C). 58 The photothermal effect of MoS 2 nanosheets results in a rapid increase in the temperature of the MoS 2 /Fe 3 O 4 gel under near-infrared light irradiation (Fig. 4D).…”

“…Chen et al 58 developed a programmable hydrogel with a controllable anisotropic structure. 2D nanomaterials with both magnetic and photothermal stimuli-responsiveness were fabricated through co-precipitating Fe 3 O 4 and anchoring poly( N -isopropyl acrylamide) (PNIPAm) on the surface of MoS 2 nanosheets prepared by a liquid-phase exfoliation method (Fig.…”

Dopamine-Modified Chitosan Patterning Hydrogel with Dynamic Information Storage Ability

“…Hydrogels can be used as a network to store the structural and functional information on molecules both macroscopically and microscopically. The dynamic control and functional regulation of assemblies can be realized by programming the interaction between stimulus-responsive molecules. − In many such studies, the encoding of synthetic polymers (e.g., heat-sensitive cross-linked polymers, , ultraviolet (UV)-sensitive ionic polymers, pH-sensitive metal chelates) as moieties that confer dynamically responsive properties is a common means. However, encoding the redox processes of stimulus-responsive substances can also be used as a way to create dynamical hydrogels.…”

Light‐Fueled Hydrogel Actuators with Controlled Deformation and Photocatalytic Activity

“…Among common external stimulation sources, such as light, [ 15 , 16 ] electricity, [ 17 , 18 ] magnetic field, [ 19 , 20 , 21 ] heat, [ 13 , 22 , 23 ] pH, [ 24 , 25 ] and chemicals, [ 2 ] near‐infrared (NIR) light has shown great potential in remote stimulation of photoresponsive materials with high selectivity, and superior tissue penetration. [ 26 , 27 ] Stimulation of photoresponsive hydrogel actuators with NIR, indeed, allows for precise spatiotemporal control of their shape‐change without damage or contact underwater.…”