Supramolecular hydrogels with responsive rheological properties based on amphiphilic peptides and cyclodextrin-modified magnetic nanoparticles

• Applicant: Professor Dr. Bart Jan Ravoo
• Subject Area: Polymer Materials ; Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 434181687

• Final Report Year: 2025

Final Report Abstract

Hydrogels are unique materials that are largely composed of water yet macroscopically behave as solids. They contain porous three-dimensional molecular networks that can entrap an amount of water that greatly surpasses the molecular mass due to capillary effects and surface tension, without dissolving. Moreover, hydrogels have viscoelastic properties very similar to human tissue. Many hydrogels are based on polymers, which interact and entangle for form a network structure beyond a threshold concentration. Recently, also hydrogels based on low molecular weight gelators have gained attention. In this case, the small molecules such as peptides self-assemble into supramolecular polymers, which in turn form the network structure that stabilizes the hydrogel. The central aim of this project was the development of innovative supramolecular peptide hydrogels that have stimulus-responsive properties based on the integration of magnetite nanoparticles. In this project, we prepared “double supramolecular” hydrogels, in which amphiphilic peptides stack in aqueous solution to form supramolecular polymers, which in addition cross-link due to non-covalent interactions with magnetite nanoparticles. Using tailor-made peptides, we prepared hydrogels that respond to an applied magnetic field and/or irradiation with UV and visible light, for example they become harder or softer, or change shape. The hydrogels were characterized in detail using photo- and magnetorheological experiments. Furthermore, the mechanical stability of the hydrogels was increased by adding a polymer as an additional component in the hydrogel. Using a combination of peptide and polymers, hydrogels with a shape memory were obtained. In short, this project provided entirely new dynamic and responsive hydrogels that can be manipulated by external stimuli.

Publications

• Magneto- and photo-responsive hydrogels from the co-assembly of peptides, cyclodextrins, and superparamagnetic nanoparticles. Faraday Discussions, 219, 220-228.
  Nowak, Benedikt P. & Ravoo, Bart Jan
  
• Photoresponsive hybrid hydrogel with a dual network of agarose and a self-assembling peptide. Soft Matter, 16(31), 7299-7304.
  Nowak, Benedikt P. & Ravoo, Bart Jan
  
• Magneto-responsive hydrogels by self-assembly of low molecular weight peptides and crosslinking with iron oxide nanoparticles. Soft Matter, 17(10), 2857-2864.
  Nowak, Benedikt P.; Niehues, Maximilian & Ravoo, Bart Jan
  
• Multiresponsive hydrogels and organogels based on photocaged cysteine. Chemical Communications, 57(48), 5913-5916.
  Rickhoff, Jonas; Cornelissen, Nicolas V.; Beuse, Thomas; Rentmeister, Andrea & Jan, Ravoo Bart
  
• Mediating Oxidation of Thioethers with Iodine—A Mild and Versatile Pathway to Trigger the Formation of Peptide Hydrogels. Angewandte Chemie International Edition, 61(22).
  Nowak, Benedikt P.; Schlichter, Lisa & Ravoo, Bart Jan
  
• Supramolecular Hydrogels Based on Cyclodextrins: Progress and Perspectives. ChemNanoMat, 8(5).
  Jain, Mehak; Nowak, Benedikt P. & Ravoo, Bart Jan