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Magnetically Addressable Hydrogels: Towards 3D Printed Spatiotemporally Resolved Thermal Dissipation and Drug Release

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posted on 09.05.2022, 10:43 by Patricia MonksPatricia Monks

Multifunctional nanocomposites which exhibit well-defined physical properties are emerging as components for advanced responsive systems, e.g., in soft robotics or drug delivery. Magnetic nanoparticles embedded in these materials (e.g., hydrogels) are attractive due to their resemblance to the extra-cellular matrix (ECM) for cell support and ability to be manipulated in situ by external magnetic fields. The ability to control the distribution of the nanoparticles has the potential to encode spatiotemporally controlled responses, either directly thermal or to trigger a drug response to manipulate cell response. Controlling this distribution at a high-resolution with spatial resolution <150 µm, sufficiently fine to be of relevance to tissue engineering, is presented.

This thesis attempts to contribute knowledge to the development of platforms and analysis for high-resolution magnetic nanoparticle hydrogel gradients. In the first instance, a 3D printing platform is developed of for an extrusion-based approach for manipulating spatial distribution of heat via magnetic hydrogels (Magnetic Nanoflower/PluronicPF127 Hydrogel) in well-defined printed features. Following on, an in-depth study of the thermal response of these gels is described where rules for heat-induction in bulk hydrogels and the heat-dependence on particle concentration, gel volume, and gel exposed surface area are established. High-concentration, high-resolution prints were shown to provide an acceptable thermal response (> 10 °C). Sufficient heat was generated to trigger a dye release potentially modelling future drug release work. This work also explores the contribution of Néel and Brownian relaxation in gels when choosing a magnetic nanoparticle candidate and touches on an alternative route to spatial patterning via curing a gel and immobilising the nanoparticles in an external magnetic field. Finally, using observations gleaned from the work undertaken above, a secondary school experiment was derived to determine the magnetic response of nanoparticles and demonstrate their unique properties to second level students. 

Overall, the approach developed here is demonstrated to have potential unobserved control over combined spatial and temporal induction of heat, the applications of which are in developing responsive scaffolds, remodelling, and cargo release for applications in regenerative medicine.

Funding

SFI 13/A/1840

History

First Supervisor

Prof. Andreas Heise

Second Supervisor

Prof. Sally-Ann Cyran

Third Supervisor

Prof. Dermot Brougham

Comments

Submitted for the Award of Doctor of Philosophy to the Royal College of Surgeons in Ireland, 2021

Published Citation

Monks, P. Magnetically Addressable Hydrogels: Towards 3D Printed Spatiotemporally Resolved Thermal Dissipation and Drug Release. [PhD Thesis]. Dublin: Royal College of Surgeons in Ireland, 2021

Degree Name

Doctor of Philosophy (PhD)

Date of award

30/11/2021

Programme

  • Doctor of Philosophy (PhD)

Research Area

  • Chemistry and Pharmaceutical Sciences
  • Biomaterials and Regenerative Medicine