An Anisotropic Hydrogel Based on Mussel-Inspired Conductive Ferrofluid Composed of Electromagnetic Nanohybrids

Abstract

Anisotropic hydrogels with a hierarchical structure can mimic biological tissues, such as neurons or muscles that show directional functions, which are important factors for signal transduction and cell guidance. Here, we report a mussel-inspired approach to fabricate an anisotropic hydrogel based on a conductive ferrofluid. First, polydopamine (PDA) was used to mediate the formation of PDA-chelated carbon nanotube-Fe3O4 (PFeCNT) nanohybrids and also used as a dispersion medium to stabilize the nanohybrids to form a conductive ferrofluid. The ferrofluid can respond to an orientated magnetic field and be programed to form aligned structures, which were then frozen in a hydrogel network formed via in situ free-radical polymerization and gelation. The resulted hydrogel shows directional conductive and mechanical properties, mimicking an oriented biological tissue. Under external electrical stimulation, the orientated PFeCNT nanohybrids can be sensed by the myoblasts cultured on the hydrogel, resulting in the oriented growth of cells. In summary, the mussel-inspired anisotropic hydrogel with its aligned structural complexity and anisotropic properties together with the cell affinity and tissue adhesiveness is a potent multifunctional biomaterial for mimicking oriented tissues to guide cell proliferation and tissue regeneration.

Recent Advances on Magnetic Sensitive Hydrogels in Tissue Engineering

“…In the process of the in situ precipitation, the network of the hydrogels acts as a chemically reactive substance, within which the iron ions from inorganic salts in hydrogels react with alkali solutions (e.g., NH 3 •H 2 O, NaOH; Arias et al, 2018;Liu et al, 2019) to prepare the magnetic particles. In detail, the hydrogels are firstly prepared through polymerization, temperature change, or a crosslinking reaction.…”

“…In addition, the in situ fabricated MNPs in the magnetic hydrogel had excellent biocompatibility and no acute toxicity on MG-63 cells (human osteosarcoma cell line). Liu et al (2019) fabricated polydopamine (PDA)-chelated carbon nanotube (CNT)-Fe 3 O 4 (PFeCNT) nanohybrids into the acrylamide hydrogel via an in situ precipitation method to generate the PFeCNT hydrogel. This magnetic hydrogel formed an anisotropic morphology under a low static magnetic field (SMF) (30 mT) and showed conductive and mechanical features.…”

Paramagnetic Functionalization of Biocompatible Scaffolds for Biomedical Applications: A Perspective

“…In addition to the shape and topography of the substrate, external stimulation such as electrical stimulation can promote muscle regeneration as it belongs to excitable tissues [167]. In a recent study, a promising hydrogel for muscle tissue regeneration has been fabricated [168]. A conductive ferrofluid was developed using a mussel-inspired approach and then used to prepare an anisotropic hydrogel that had both magnetic and conductive properties at the same time.…”

The combination of multi-functional ingredients-loaded hydrogels and three-dimensional printed porous titanium alloys for infective bone defect treatment

“…hydrophobic interactions, π-π stacking, Van der Waals forces, and hydrogen bonds). As a result, this formulation hydrogel not only have advantages of traditional hydrogels, but also integrate the unique properties of nanoparticles, for instance, fluorescence, 22 adhesion, 23 − 26 biological activity, 27 conductivity, 28 , 29 as well as magnetic properties. 30 Therefore, the rational design of hydrogels with controlled physical and biological properties can be used to regulate 3D printed implants functionality.…”