Emerging Magnetic Fabrication Technologies Provide Controllable Hierarchically‐Structured Biomaterials and Stimulus Response for Biomedical Applications

Abstract

Multifunctional nanocomposites which exhibit well‐defined physical properties and encode spatiotemporally‐controlled responses are emerging as components for advanced responsive systems. For biomedical applications magnetic nanocomposite materials have attracted significant attention due to their ability to respond to spatially and temporally varying magnetic fields. The current state‐of‐the‐art in development and fabrication of magnetic hydrogels toward biomedical applications is described. There is accelerating progress in the field due to advances in manufacturing capabilities. Three categories can be identified: i) Magnetic hydrogelation, DC magnetic fields are used during solidification/gelation for aligning particles; ii) additive manufacturing of magnetic materials, 3D printing technologies are used to develop spatially‐encoded magnetic properties, and more recently; iii) magnetic additive manufacturing, magnetic responses are applied during the printing process to develop increasingly complex structural arrangement that may recapitulate anisotropic tissue structure and function. The magnetic responsiveness of conventionally and additively manufactured magnetic hydrogels are described along with recent advances in soft magnetic robotics, and the categorization is related to final architecture and emergent properties. Future challenges and opportunities, including the anticipated role of combinatorial approaches in developing 4D‐responsive functional materials for tackling long‐standing problems in biomedicine including production of 3D‐specified responsive cell scaffolds are discussed.

Perspectives on recent advancements in energy harvesting, sensing and bio-medical applications of piezoelectric gels

“…[232][233][234][235] Over the years, gelatin-based materials have been extensively explored due to their low cost, non-toxicity, biocompatibility, nonimmunogenicity, biodegradability, as well as attractive chemical and physical features including water solubility, transparency, high tensile strength, and outstanding piezoelectric properties. [236][237][238][239][240][241][242][243][244] Ma and coworkers reported the mechanoelectrical properties of soft and wet gelatin gel under an applied load of 9.8 N (Fig. 4b-d).…”

“…232–235 Over the years, gelatin-based materials have been extensively explored due to their low cost, non-toxicity, biocompatibility, nonimmunogenicity, biodegradability, as well as attractive chemical and physical features including water solubility, transparency, high tensile strength, and outstanding piezoelectric properties. 236–244…”

Fabrication and Actuation of Magnetic Shape-Memory Materials

“…Soft robotics is a field of robotics that is based on the use of easily deformable, mechanically resilient materials intended for a variety of applications, such as soft grippers and artificial muscles. − Unlike their rigid counterparts, soft robotic materials are intrinsically safe for contact use with humans such as in medical devices. These soft actuators can change dimensions and/or shape and can undergo locomotion, in response to stimuli such as pH, light, heat, solvent, electric or magnetic fields, etc. − Among these stimuli, applied magnetic fields are one of the most attractive ways of actuation, due to their ease of application, prompt response, and safety in biological systems. − …”

Magnetic Chitosan Bionanocomposite Films as a Versatile Platform for Biomedical Hyperthermia

“…[21][22][23][24][25][26][27] Dispersion and stabilization of MNPs in polymers to form responsive nanocomposites is an alternative approach that may overcome many limitations of suspension-based MH. Nanocomposite materials which combine MNPs with chemically defined polymers or hydrogels, in bulk or film formats, provide field-responsiveness [3,4,28,29] and particle retention/localization. In previous work, we have shown that MNPs can be stabilized in patternable synthetic hydrogels and that the MH thermoresponse of the nanocomposite is controlled by concentrationdependent interactions between MNPs that are modulated by their surface chemistry.…”

“…[1,2] Responsive magnetic materials have been proposed as functional components for cancer therapies that may provide spatiotemporal-controlled drug release actuated by magnetic hyperthermia (MH) under alternating magnetic field (AMF) stimulation. [3][4][5] The approach relies on heat dissipation by MNPs under AMF, which is feasible as magnetic fields permeate most soft hydrated materials including the human body. [6,7] MNPs are widely used for MH cancer therapy due to their high magnetization, optimizable moment dynamics, biocompatibility, biodegradability, and relatively easy synthesis.…”