Dynamic and biocompatible thermo-responsive magnetic hydrogels that respond to an alternating magnetic field

Abstract

Magnetic thermo-responsive hydrogels are a new class of materials that have recently attracted interest in biomedicine due to their ability to change phase upon magnetic stimulation. They have been used for drug release, magnetic hyperthermia treatment, and can potentially be engineered as stimuli-responsive substrates for cell mechanobiology. In this regard, we propose a series of magnetic thermo-responsive nanocomposite substrates that undergo cyclical swelling and de-swelling phases when actuated by an alternating magnetic field in aqueous environment. The synthetized substrates are obtained with a facile and reproducible method from poly-N-isopropylacrylamide and superparamagnetic iron oxide nanoparticles. Their conformation and the temperature-related, magnetic, and biological behaviors were characterized via scanning electron microscopy, swelling ratio analysis, vibrating sample magnetometry, alternating magnetic field stimulation and indirect viability assays. The nanocomposites showed no cytotoxicity with fibroblast cells, and exhibited swelling/deswelling behavior near physiological temperatures (around 34°C). Therefore these magnetic thermo-responsive hydrogels are promising materials as stimuli-responsive substrates allowing the study of cell-behavior by changing the hydrogel properties in situ.

Spatiotemporally Resolved Heat Dissipation in 3D Patterned Magnetically Responsive Hydrogels

“…MNP polymer nanocomposites can in principle respond to applied AMF to induce structural changes and to program functional responses such as stimulating time‐dependent deformation or release of cargo on demand. [ 18–21 ] The inclusion of MNPs aligned in situ by magnetic fields during gelation has the potential to create composite matrices with well‐defined spatial topography to directionally influence the growth of cellular protrusions, such as neurites [ 22,23 ] or whole cellular constructs, such as organoids. [ 24 ] 3D printing technologies have already contributed to the fabrication of multi‐responsive and hierarchically organized soft nanocomposite hydrogels providing well‐defined environments for cell manipulation.…”

Trinity of Three-Dimensional (3D) Scaffold, Vibration, and 3D Printing on Cell Culture Application: A Systematic Review and Indicating Future Direction

“…This could evidentially benefit aspects, such as design flexibility and structural fabricability in future 3D scaffolds when focusing on potential design requirements of 3D vibratory scaffold. In addition, feasible with a wider range of 3DP materials that are equipped with electrical, optical properties and dynamic or magnetic properties [ 59 , 98 , 99 , 101 , 102 ], material composition concerns for 3D vibratory scaffold might benefit most from 3DP technologies when compared with other fabrication tools. As new biocompatible materials and “bio-inks” being created or synthesized [ 35 , 103 , 104 ], 3D printed scaffolds used in tissue and cell engineering tend to become more effective in cell culture applications, and this helps to cooperate with future scaffolds, which tend to have the same application as cultivating cells.…”

Magnetic microgels and nanogels: Physical mechanisms and biomedical applications

“…During the designing of these hybrids, 99 Another key aspect in the physical design of magnetic gel hybrids is the time scale of gel swelling and deswelling in response to the applied magnetic fields. In particular, for repeated volume phase transition of MNP-laden thermoresponsive hydrogels, 100,101 it is important to optimize the kinetics of gel collapsing and reswelling, coupled to the magnetic heating rate and efficacy. In this case, the relaxation time required for the polymer chain reconfiguration in the absence of the alternating magnetic field could be a limiting factor for the pulsatile actuation performance of the hybrid gel devices.…”