Dehydropeptide-based plasmonic magnetogels: a supramolecular composite nanosystem for multimodal cancer therapy

Supramolecular hydrogels are highly promising for biomedical materials owing to the wide array of properties that can be tailored and modulated. The combination with plasmonic/magnetic nanoparticles into plasmonic magnetogels further improve its potential in biomedical applications, through the combination of complementary strategies, such as photothermia, magnetic hyperthermia, photodynamic therapy and magnetic-guided drug delivery. Here, a new dehydropeptide hydrogelator, Npx-L-Met-Z-ΔPhe-OH, was developed and combined with two different plasmonic/magnetic nanoparticles architectures: core/shell manganese ferrite/gold nanoparticles or gold-decorated manganese ferrite nanoparticles with ca. 55 nm and 45 nm size, respectively. The characterization of magnetogels were performed by HR-TEM, FTIR, circular dichorism and rheological assays. The gels were tested as nanocarriers for a model antitumor drug, the natural compound curcumin. The incorporation of the drug in magnetogel matrices was confirmed through fluorescence-based techniques (FRET, fluorescence anisotropy and quenching). The curcumin release profiles were studied with and without excitation of the gold plasmon band. The transport of curcumin from magnetogels towards biomembrane models (small unilamellar vesicles) was assessed by FRET between the fluorescent drug and the lipid probe Nile Red. The developed magnetogels showed promising results for photothermia and photo-triggered drug release. The magnetogels bearing gold-decorated nanoparticles showed the best photothermia properties, while the ones containing core/shell nanoparticles had the best photoinduced curcumin release.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2019) and CQUM (UID/QUI/00686/ 2019). FCT, FEDER, PORTUGAL2020 and COMPETE2020 are also acknowledged for funding under research projects PTDC/QUIQFI/28020/2017 (POCI-01-0145-FEDER-028020) and PTDC/QUIQOR/29015/2017 (POCI-01-0145-FEDER-029015). The magnetic measurements were supported by projects UTAP-EXPL/NTec/0046/2017, NORTE-01-0145-FEDER-028538 and PTDC/FIS-MAC/29454/2017. Authors gratefully acknowledge Dr L. M. Vieira for carrying out the FTIR measurements at the Infrared Spectroscopy Lab. of the Centre of Physics, Univ. Minho