posted on 2022-10-21, 21:13authored byCaio J. Perecin, Mattia Sponchioni, Renato Auriemma, Natalia N. P. Cerize, Davide Moscatelli, Laudemir C. Varanda
Tailor-made materials for biomedical applications can
be constructed with different building blocks to confer multiple functions
on one platform. Here, we demonstrate the facile synthesis of magnetite-biodegradable
polymer nanocomposites combining superparamagnetism with the possibility
of loading and controlling the release of a lipophilic drug. The magnetite
nanoparticles were synthesized by reduction–precipitation and
used as nuclei to grow a biodegradable zwitterionic shell. The copolymer
used for this scope comprises a hydrophobic block made of a biodegradable ε-caprolactone-based
macromonomer (CLn) with three different
degrees of polymerization (DPn, n = 3, 5, and 7) obtained by ring-opening polymerization
(ROP). Dopamine molecules were attached to the end of this CLn oligomer (CLnDopa),
conferring a specific affinity for the magnetite surface. A hydrophilic
zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) block
(PMPC) was included by reversible addition–fragmentation chain
transfer (RAFT) polymerization to add colloidal stability and water
dispersibility to the copolymer. This PMPC was chain-extended with
CLnDopa via RAFT polymerization targeting
four different DPm (m = 10, 20, 30, and 40), resulting in a library of 12 copolymers.
A facile nanoprecipitation process produced copolymer nanoparticles
and copolymer-coated magnetite nanostructures. Physicochemical characterization
confirmed the inorganic–organic composite nature. The copolymer-coated
magnetic materials showed water stability, superparamagnetic behavior,
and appropriate hyperthermic ability under an alternate magnetic field.
Biological assays using HeLa cells showed high biocompatibility and
efficient nanoparticle uptake. In addition, a sustained release of
dexamethasone, used as a model drug encapsulated in the polymer shell,
and local heating as a dual functional material could be accessed.