Inorganic nanoparticles have been introduced into biological systems as useful probes for in vitro diagnosis and in vivo imaging, due to their relatively small size and exceptional physical and chemical properties. A new kind of colortunable Gd-Zn-Cu-In-S/ZnS (GZCIS/ZnS) quantum dots (QDs) with stable crystal structure has been successfully synthesized and utilized for magnetic resonance (MR) and fluorescence dual modality imaging. This strategy allows successful fabrication of GZCIS/ZnS QDs by incorporating Gd into ZCIS/ZnS QDs to achieve great MR enhancement without compromising the fluorescence properties of the initial ZCIS/ZnS QDs. The as-prepared GZCIS/ZnS QDs show high T₁ MR contrast as well as "color-tunable" photoluminescence (PL) in the range of 550–725 nm by adjusting the Zn/Cu feeding ratio with high PL quantum yield (QY). The GZCIS/ZnS QDs were transferred into water via a bovine serum albumin (BSA) coating strategy. The resulting Cd-free GZCIS/ZnS QDs reveal negligible cytotoxicity on both HeLa and A549 cells. Both fluorescence and MR imaging studies were successfully performed in vitro and in vivo. The results demonstrated that GZCIS/ZnS QDs could be a dual-modal contrast agent to simultaneously produce strong MR contrast enhancement as well as fluorescence emission for in vivo imaging.

Magnetic nanoparticles have been used as drug delivery vehicles against a number of cancer cells. Most of these theranostic formulations have used solid iron oxide nanoparticles (SIONPs) loaded with chemotherapeutics as nano-carrier formulation for both magnetic resonance imaging (MRI) and cancer therapy. In this study, we applied the dopamine-plus-human serum albumin (HSA) method to modify hollow iron oxide nanoparticles (HIONPs) and encapsuated doxorubicin (DOX) within the hollow porous structure of the nano-carrier. The new delivery system can load more drug than solid iron oxide nanoparticles of the same core size using the same coating strategy. The HIONPs–DOX formulation also has a pH-dependent drug release behaviour. Compared with free DOX, the HIONPs–DOX were more effectively uptaken by the multidrug resistant OVCAR8-ADR cells and consequently more potent in killing drug resistant cancer cells. MRI phantom and cell studies also showed that the HIONPs–DOX can decrease the T₂ MRI signal intensity and can be used as a MRI contrast agent while acting as a drug delivery vehicle. For the first time, the dual application of chemo drug transport and MR imaging using the HIONPs–DOX formulation was achieved against both DOX-sensitive and DOX-resistant cancer cells.

Plasmonics and chirality in metal nanomaterials are intriguing and inspiring phenomena. Nanoscale chirality of metal nanomaterials has emerged as a hot topic in the past several years. Generally, most plasmon-induced circular dichroism (CD) responses of nanomaterials (> 10 nm) have been artificially created by modifying pre-made achiral nanomaterials with chiral agents, because the in situ generation of plasmon-induced CD responses of nanomaterials with larger size (> 10 nm) is not easy. Herein, we report a simple one-pot green synthesis of chiral gold nanoflowers (GNFs) with abundant petal-shaped tips in the chiral reduction environment arising from the presence of chiral guanosine 5ʹ-monophosphate (5ʹ-GMP) and the chiral reducing agent L-ascorbic acid (L-AA). Different reducing agents can impact the shape and chirality of the products. In addition, the size and chirality of the GNFs can be controlled by adjusting the reaction time. The as-synthesized GNFs have good biocompatibility and can be used for surface-enhanced Raman scattering (SERS) enhancement, cellular dark-field imaging and photothermal therapy.