Photothermal therapy (PTT) has attracted considerable attention in cancer treatment. Herein, the facile synthesis of copper iron sulfide (chalcopyrite, CuFeS2) nanoplates (NPs) with well-defined shape was achieved by a template-mediated method. Chitosan (CS), a linear cationic polysaccharide, was used to improve the physiological stability and biocompatibility. CuFeS2 NPs with strong near-infrared (NIR) absorbance enabled contrasts in photothermal and photoacoustic (PA) imaging. In vitro and in vivo tumor ablation studies further demonstrated that CS-functionalized CuFeS2 (CuFeS2-CS) NPs could convert 808 nm NIR light into heat for PTT with a photothermal conversion efficiency up to 30.5%, which was clearly higher than that of CuS NPs (only 21.4%). Furthermore, CuFeS2-CS NPs could also load cis-platinum pro-drug (CuFeS2-CS-Pt), and CuFeS2-CS-Pt showed a better synergistic therapeutic effect with respect to either chemotherapy or PTT.

Elaborately designed biocompatible nanoplatforms simultaneously achieving multimodal bioimaging and therapeutic functions are highly desirable for modern biomedical applications. Herein, uniform MoS2 nanoflowers with a broad size range of 80–180 nm have been synthesized through a facile, controllable, and scalable hydrothermal method. The strong absorbance of MoS2 nanoflowers at 808 nm imparts them with high efficiency and stability of photothermal conversion. Then a novel multifunctional composite of MoS2@Fe3O4-ICG/Pt(IV) (labeled as Mo@Fe-ICG/Pt) is designed by covalently grafting Fe3O4 nanoparticles with polyethylenimine (PEI) functionalized MoS2, and then loading indocyanine green molecules (ICG, photosensitizers) and platinum (IV) prodrugs (labeled as Pt(IV) prodrugs) on the surface of MoS2@Fe3O4. The resulting Mo@Fe-ICG/Pt nanocomposites can achieve excellent magnetic resonance/infrared thermal/photoacoustic trimodal biomaging as well as remarkably enhanced antitumor efficacy of combined photothermal therapy, photodynamic therapy, and chemotherapy triggered by a single 808 nm NIR laser, thus leading to an ideal nanoplatform for cancer diagnosis and treatment in future.

Gd2O3:Yb3+,Er3+@nSiO2@mSiO2 (Gd@mSi) core/shell structure nanospheres were synthesized through a sol–gel method. Then biocompatible polysaccharide chitosan (CS) was grafted onto the surface of the nanoparticles to fabricate a pH responsive CS@Gd@mSi system. Furthermore, cancer targeting ligand folic acid (FA) was modified through the abundant amino groups on the chitosan polymer shell. The nanospheres with a Gd2O3:Yb3+,Er3+ core can be candidates for T1-weighted magnetic resonance imaging (MRI) contrast agents. The CS decorated nanocomposites showing good biocompatibility and red emission under 980 nm laser excitation can be potential candidates for bioimaging in vitro. FA modified nanospheres loaded with doxorubicin hydrochloride (DOX) show higher cytotoxicity for HeLa cells in vitro compared with those nanoparticles with chitosan shells only and pure DOX. The CS@Gd@mSi system can be a potential drug carrier with MRI, UCL, and finely controlled pH-dependent drug release properties.

Eukaryotic translation initiation factor (eIF) 4E is a valuable marker in cancer prognostics in many human cancers. Silencing eIF4E via delivery of siRNA may be able to overcome chemoresistance. Cisplatin, used as a first-line anti-cancer reagent, has been widely accepted for its great success in clinical applications but it is restricted due to severe side effects such as nephrotoxicity, peripheral neuropathy, and hearing loss. Moreover, platinum drug resistance is a major obstacle to its use. Platinum(IV) prodrugs (denoted as Pt(IV)) which could be reduced to Pt(II) by various reductants, including mercaptan and glutathione, within cancer cells have very limited toxicity and might overcome platinum resistance because of their chemical inertness. Moreover, combinational therapies that could sensitize the cancer cells to Pt drugs have received great attention nowadays around the world. Here we report a simple and effective upconversion nanoparticle carrier system loaded with both eIF4E siRNA and Pt(IV). We find that this theranostic system could sensitize laryngeal cancer cells to cisplatin based chemotherapy and allow bioimaging both in vitro and in vivo.

Mesoporous silica nanoparticles (MSNs) were firstly functionalized with upconversion luminescent Gd2O3:Yb3+,Er3+ via the Pechini sol–gel method. Then, polyelectrolyte multilayers (PEM) composed of poly(allyamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) were coated onto the Gd2O3:Yb3+,Er3+@MSNs using a layer-by-layer (LbL) technique to achieve the pH-responsive properties of the nanocarriers. PEM@Gd2O3:Yb3+,Er3+@MSNs loaded with doxorubicin hydrochloride (DOX) showed pH-responsive release and higher cytotoxicity towards MCF-7 breast cancer cells in vitro. Nanocomposites functionalized with Gd2O3:Yb3+,Er3+ can serve as T1-weighted magnetic resonance imaging (MRI) contrast agents. Nanoparticles emitting red signals under 980 nm laser excitation are suitable for use in potential bioimaging applications. The upconversion luminescent (UCL) intensity of PEM-coated nanocomposites can be adjusted by controlling the number of layers of the PAH/PSS coating. The PEM@Gd2O3:Yb3+,Er3+@MSNs can be used as a potential drug delivery system for MRI, UCL imaging, and pH-responsive chemotherapy.

Nanoparticles have been explored as nonviral gene carriers for years because of the simplicity of surface modification and lack of immune response. Lanthanide-based upconversion nanoparticles (UCNPs) are becoming attractive candidates for biomedical applications in virtue of their unique optical properties and multimodality imaging ability. Here, we report a UCNPs-based structure with polyethylenimine coating for both efficient gene transfection and trimodality imaging. Cytotoxicity tests demonstrated that the nanoparticles exhibited significantly decreased cytotoxicity compared to polyethylenimine polymer. Further, in vitro studies revealed that the gene carriers are able to transfer the enhanced green fluorescence protein (EGFP) plasmid DNA into Hela cells in higher transfection efficiency than PEI. Gene silencing was also examined by delivering bcl-2 siRNA into Hela cells, resulting in significant downregulation of target bcl-2 mRNA. More importantly, we demonstrated the feasibility of upconversion gene carriers to serve as effective contrast agents for MRI/CT/UCL trimodality imaging both in vitro and in vivo. The facile fabrication process, great biocompatibility, enhanced gene transfection efficiency, and great bioimaging ability can make it promising for application in gene therapy.

Controlling anticancer drug activity and release on demand is very significant in cancer therapy. The photoactivated platinum(IV) pro-drug is stable in the dark and can be activated by UV light. In this study, we develop a multifunctional drug delivery system combining upconversion luminescence/magnetic resonance/computer tomography trimodality imaging and NIR-activated platinum pro-drug delivery. We use the core–shell structured upconversion nanoparticles to convert the absorbed NIR light into UV to activate the trans-platinum(IV) pro-drug, trans,trans,trans-[Pt(N3)2(NH3)(py)(O2CCH2CH2COOH)2]. Compared with using the UV directly, the NIR has a higher tissue penetration depth and is less harmful to health. Meanwhile, the upconversion nanoparticles can effectively deliver the platinum(IV) pro-drugs into the cells by endocytosis. The mice treated with pro-drug-conjugated nanoparticles under near-infrared (NIR) irradiation demonstrated better inhibition of tumor growth than that under direct UV irradiation. This multifunctional nanocomposite could be used as multimodality bioimaging contrast agents and transducers by converting NIR light into UV for control of drug activity in practical cancer therapy.

Eukaryotic translation initiation factor (eIF) 4E is a valuable marker in cancer prognostics in many human cancers. Silencing eIF4E via delivery of siRNA may be able to overcome chemoresistance. Cisplatin, used as a first-line anti-cancer reagent, has been widely accepted for its great success in clinical applications but it is restricted due to severe side effects such as nephrotoxicity, peripheral neuropathy, and hearing loss. Moreover, platinum drug resistance is a major obstacle to its use. Platinum(IV) prodrugs (denoted as Pt(IV)) which could be reduced to Pt(II) by various reductants, including mercaptan and glutathione, within cancer cells have very limited toxicity and might overcome platinum resistance because of their chemical inertness. Moreover, combinational therapies that could sensitize the cancer cells to Pt drugs have received great attention nowadays around the world. Here we report a simple and effective upconversion nanoparticle carrier system loaded with both eIF4E siRNA and Pt(IV). We find that this theranostic system could sensitize laryngeal cancer cells to cisplatin based chemotherapy and allow bioimaging both in vitro and in vivo.