Combined treatment based on tumor-targeted nanoparticles has become one of the most promising anticancer strategies. Moreover, bispecific antibodies have been designed as linkers to promote the interaction between natural killer (NK) cells and tumor cells, while triggering NK cell-mediated target cell lysis. Here, we adopted a novel design that uses PEGylated hollow mesoporous ruthenium nanoparticles as a carrier to load the fluorescent anti-tumor complex ([Ru(bpy)₂(tip)]²⁺, RBT) and a conjugate with bispecific antibodies (SS-Fc). By accurately targeting carcinoembryonic antigen overexpressed in colorectal cancer cells, HMRu@RBT-SS-Fc significantly improved selective penetration in vitro. The functionalized nanocomplex effectively engaged NK cells and possessed excellent near infrared-sensitive cytotoxicity. Systematic in vivo studies clearly demonstrated the high tumor targeting and anticancer activity in heterotopic colorectal tumor model via combined photothermal and immune therapy. This nanosystem establishes a new platform for future image-guided drug delivery and highly efficient cancer therapy.

Methotrexate (MTX) is a drug that is used for the clinical treatment of rheumatoid arthritis (RA), a stubborn disease caused by over-immunization. However, the toxicity that arises as a result of poor selectivity to inflammatory cells severely limits the application of MTX. Therefore, new therapeutic strategies are needed for treating RA. Here, we describe the design and synthesis of a nanotherapy agent, Pd-Cys@MTX@RGD, which can target inflammatory cells and control MTX release. The novel hexagonal palladium (Pd) nanosheets were used as a near-infrared (NIR) photothermal agent modified with arginine-glycineaspartic acid (RGD) peptides on the surface to enhance the ability of the nanosheet targeting of inflammatory cells. In subsequent experiments, the Pd-Cys@MTX@RGD nanosheets were observed to greatly reduce the toxicity of MTX, showing controlled MTX release under irradiation of 808 nm (0.3 W cm⁻²). Moreover, taking advantage of the fact that MTX can be combined with multiple therapeutic methods, the photothermal therapy (PTT) of Pd nanosheets provided a compensatory effect to enhance the therapeutic efficacy of MTX. Under combination therapy, Pd-Cys@MTX@RGD was shown to effectively inhibit the inflammatory response induced by vascular endothelial growth factor (VEGF) and IL-1β. And, in vivo, multifunctional Pd-Cys@MTX@RGD effectively inhibited the symptoms of RA by inhibiting the expression of pro-inflammatory cytokines (TNF-α,COX-2). We hope that the construction of nanomaterials can add potential value to the design of chemical drugs and therapeutic strategies for RA.

Schematic illustration for the formation and in vivo treatment process of PdRu-RCE@PCM NPs.