Pancreatic cancer is one of the deadliest human cancers, whose progression is highly dependent on the nervous microenvironment. The suppression of gene expression of nerve growth factor (NGF) may have great potential in pancreatic cancer treatment. Here we show that gold nanocluster-assisted delivery of siRNA of NGF (GNC–siRNA) allows efficient NGF gene silencing and pancreatic cancer treatment. The GNC–siRNA complex increases the stability of siRNA in serum, prolongs the circulation lifetime of siRNA in blood and enhances the cellular uptake and tumour accumulation of siRNA. The GNC–siRNA complex potently downregulates the NGF expression in Panc-1 cells and in pancreatic tumours, and effectively inhibits the tumour progression in three pancreatic tumour models (subcutaneous model, orthotopic model and patient-derived xenograft model) without adverse effects. Our study constitutes a straightforward but effective approach to inhibit pancreatic cancer via NGF knockdown, suggesting a promising therapeutic direction for pancreatic cancer.

SummaryStretchable, biocompatible devices can bridge electronics and biology. However, most stretchable conductors for such devices are toxic, costly, and regularly break/degrade after several large deformations. Here we show printable, highly stretchable, and biocompatible metal-polymer conductors by casting and peeling off polymers from patterned liquid metal particles, forming surface-embedded metal in polymeric hosts. Our printable conductors present good stretchability (2,316 S/cm at a strain of 500%) and repeatability (ΔR/R <3% after 10,000 cycles), which can satisfy most electrical applications in extreme deformations. This strategy not only overcomes large surface tension of liquid metal but also avoids the undesirable sintering of its particles by stress in deformations, such that stretchable conductors can form on various substrates with high resolution (15 μm), high throughput (∼2,000 samples/hour), and low cost (one-quarter price of silver). We use these conductors for stretchable circuits, motion sensors, wearable glove keyboards, and electroporation of live cells.

Electronic tattoos have great potential in health and movement sensing applications on the skin. However, existing electronic tattoos cannot be conformal, sticky, and multilayered at the same time. Here, we have achieved multilayered integration of the electronic tattoo that is highly stretchable (800%), conformal, and sticky. This electronic tattoo can enable the crease amplification effect, which can amplify the output signal of integrated strain sensors by three times. The tattoo can be transferred to different surfaces and form a firm attachment, where no solvent or heat is needed. The tattoo fabrication is straightforward and scalable; a layer-by-layer strategy and two materials (metal-polymer conductors and the elastomeric block copolymer) are used to fabricate the circuit module with desirable numbers of layers within the tattoo. A three-layered tattoo integrating 1 heater and 15 strain sensors is developed for temperature adjustment, movement monitoring, and remote control of robots.