Laser-induced thermal response and controlled release of copper oxide nanoparticles from multifunctional polymeric nanocarriers.

Multifunctional nanocarriers have attracted considerable interest in improving cancer treatment outcomes. Poly(lactide-co-glycolide) (PLGA) nanospheres encapsulating copper oxide nanoparticles (CuO-NPs) are characterized by antitumor activity and exhibit dual-modal contrast-enhancing capabilities. An in vitro evaluation demonstrates that this delivery system allows controlled and sustained release of CuO-NPs. To achieve localized release on demand, an external stimulation by laser irradiation is suggested. Furthermore, to enable simultaneous complementary photothermal therapy, polydopamine (PDA) coating for augmented laser absorption is proposed. To this aim, two formulations of CuO-NPs loaded nanospheres are prepared from PLGA polymers RG-504 H (H-PLGA) and RG-502 H (L-PLGA) as scaffolds for surface modification through in situ polymerization of dopamine and then PEGylation. The obtained CuO-NPs-based multifunctional nanocarriers are characterized, and photothermal effects are examined as a function of wavelength and time. The results show that 808 nm laser irradiation of the coated nanospheres yields maximal temperature elevation (T = 41°C) and stimulates copper release at a much faster rate compared to non-irradiated formulations. Laser-triggered CuO-NP release is mainly depended on the PLGA core, resulting in faster release with L-PLGA, which also yielded potent anti-tumor efficacy in head and neck cancer cell line (Cal-33). In conclusion, the suggested multifunctional nanoplatform offers the integrated benefits of diagnostic imaging and laser-induced drug release combined with thermal therapy.

Molecular self-assembly under nanoconfinement: indigo carmine scroll structures entrapped within polymeric capsules.

Molecular self-assembly forms structures of well-defined organization that allow control over material properties, affording many advanced technological applications. Although the self-assembly of molecules is seemingly spontaneous, the structure into which they assemble can be altered by carefully modulating the driving forces. Here we study the self-assembly within the constraints of nanoconfined closed spherical volumes of polymeric nanocapsules, whereby a mixture of polyester-polyether block copolymer and methacrylic acid methyl methacrylate copolymer forms the entrapping capsule shell of nanometric dimensions. We follow the organization of the organic dye indigo carmine that serves as a model building unit due to its tendency to self-assemble into flat lamellar molecular sheets. Analysis of the structures formed inside the nanoconfined space using cryogenic-transmission electron microscopy (cryo-TEM) and cryogenic-electron tomography (cryo-ET) reveal that confinement drives the self-assembly to produce tubular scroll-like structures of the dye. Combined continuum theory and molecular modeling allow us to estimate the material properties of the confined nanosheets, including their elasticity and brittleness. Finally, we comment on the formation mechanism and forces that govern self-assembly under nanoconfinement.