Endo/lysosomal escape and gene release are two critical bottlenecks in gene delivery. Herein, a novel photo-controllable metal-organic frameworks (MOFs) nanoswitch is rationally designed for enhancing small interfering RNA (siRNA) delivery. One single laser triggers the "off-to-on" switching of MOFs nanocomplexes, inducing significant siRNA release accompanied by rapid MOFs dissociation into protonatable 2-methylimidazalo and osmotic rupturing Zn²⁺ ions, which cooperatively contribute to remarkable endo/lysosomal rupture (~ 90%). The simultaneous endo/lysosomal rupture and release enable a high spatio-temporal control on RNA interference for effective cancer therapy. Notably, the "off-to-on" switching also activates fluorescence recovery for real-time monitoring siRNA delivery. The nanoswitch could easily be extended to deliver other therapeutic agents (e.g., DNA, protein, anticancer drug) for overcoming endo/lysosomal entrapment.

Two-dimensional (2D) nanosheets have emerged as an important class of nanomaterial with great potential in the field of biomedicines, particularly in cancer theranostics. However, owing to the lack of effective methods that synthesize uniform 2D nanomaterials with controlled size, systematic evaluation of size-dependent bio-behaviors of 2D nanomaterials is rarely reported. To the best of our knowledge, we are the first to report a systematic evaluation of the influence of size of 2D nanomaterials on their bio-behaviors. 2D Pd nanosheets with diameters ranging from 5 to 80 nm were synthesized and tested in cell and animal models to assess their size-dependent bioapplication, biodistribution, elimination, toxicity, and genomic gene expression profiles. Our results showed size significantly influences the biological behaviors of Pd nanosheets, including their photothermal and photoacoustic effects, pharmacokinetics, and toxicity. Compared to larger-sized Pd nanosheets, smaller-sized Pd nanosheets exhibited more advanced photoacoustic imaging and photothermal effects upon ultralow laser irradiation. Moreover, in vivo results indicated that 5-nm Pd nanosheets escape from the reticuloendothelial system with a longer blood half-life and can be cleared by renal excretion, while Pd nanosheets with larger sizes mainly accumulate in the liver and spleen. The 30-nm Pd nanosheets exhibited the highest tumor accumulation. Although Pd nanosheets did not cause any appreciable toxicity at the cellular level, we observed slight lipid accumulation in the liver and inflammation in the spleen. Genomic gene expression analysis showed that 80-nm Pd nanosheets interacted with more cellular components and affected more biological processes in the liver, as compared to 5-nm Pd nanosheets. We believe this work will provide valuable information and insights into the clinical application of 2D Pd nanosheets as nanomedicines.