RESUMEN
SnO2is widely used for ethanol-sensing applications due to its excellent physicochemical properties, low toxicity and high sensitivity. However it is a challenge to construct 3D-hierarchical structures with sub 5 nm primary grain particle, which is the optimized size for ethanol sensor. Herein, genetic tri-level hierarchical SnO2microstructures are synthesised by the genetic conversion of 3D hierarchical SnS2flowers assembled by ultrathin nanosheets. The SnS2nanosheets are morphology genetic converted to porous nanosheets with sub 5 nm SnO2nanoparticles during the calcination process. When used for the detection of ethanol, the sensor exhibits a high sensitivity of 0.5 ppm (Ra/Rg = 6.8) and excellent gas-sensing response (Ra/Rg= 183 to 100 ppm) with short response/recovery time (12 s/11 s). The excellent gas sensing performance is much better than that of the previous reported SnO2-based sensors. The highly sensitivity is attributed to the large surface area derived from the recrystallization and volume changes, which offers more active sites during the morphology genetic conversion from SnS2to SnO2. Furthermore, the flower-like 3D structure enhances the stability of the materials and is beneficial for the mass diffusion dynamics of ethanol.
RESUMEN
Inspired by the nature, lotus leaf-derived gradient hierarchical porous C/MoS2 morphology genetic composites (GHPCM) were successfully fabricated through an in situ strategy. The biological microstructure of lotus leaf was well preserved after treatment. Different pores with gradient pore sizes ranging from 300 to 5 µm were hierarchically distributed in the composites. In addition, the surface states of lotus leaf resulted in the Janus-like morphologies of MoS2. The GHPCM exhibit excellent electromagnetic wave absorption performance, with the minimum reflection loss of - 50.1 dB at a thickness of 2.4 mm and the maximum effective bandwidth of 6.0 GHz at a thickness of 2.2 mm. The outstanding performance could be attributed to the synergy of conductive loss, polarization loss, and impedance matching. In particularly, we provided a brand-new dielectric sum-quotient model to analyze the electromagnetic performance of the non-magnetic material system. It suggests that the specific sum and quotient of permittivity are the key to keep reflection loss below - 10 dB within a certain frequency range. Furthermore, based on the concept of material genetic engineering, the dielectric constant could be taken into account to seek for suitable materials with designable electromagnetic absorption performance.
RESUMEN
Morphology genetic biomedical materials (MGBMs), referring to fabricating materials by learning from the genetic morphologies and strategies of natural species, hold great potential for biomedical applications. Inspired by the cargo-carrying-bacterial therapy (microbots) for cancer treatment, a MGBM (artificial microbots, AMBs) was constructed. Rather than the inherent bacterial properties (cancerous chemotaxis, tumor invasion, cytotoxicity), AMBs also possessed ingenious nitric oxide (NO) generation strategy. Mimicking the bacterial construction, the hyaluronic acid (HA) polysaccharide was induced as a coating capsule of AMBs to achieve long circulation in blood and specific tissue preference (tumor tropism). Covered under the capsule-like polysaccharide was the combinatorial agent, the self-assembly constructed by the amphiphilic dendrons with abundant l-arginine residues peripherally (as endogenous NO donor) and hydrophobic chemotherapeutic drugs at the core stacking on the surface of SWNTs (the photothermal agent) for a robust chemo-photothermal therapy (chemo-PTT) and the elicited immune therapy. Subsequently, the classic inducible nitric oxide synthase (iNOS) pathway aroused by immune response was revolutionarily utilized to oxidize the l-arginine substrates for NO production, the process for which could also be promoted by the high reactive oxygen species level generated by chemo-PTT. The NO generated by AMBs was intended to regulate vasodilation and cause a dramatic invasion (as the microbots) to disperse the therapeutic agents throughout the solid tumor for a much more enhanced curative effect, which we defined as "self-propulsion". The self-propelled AMBs exhibiting impressive primary tumor ablation, as well as the distant metastasis regression to conquer the metastatic triple negative breast cancer, provided pioneering potential therapeutic opportunities, and enlightened broad prospects in biomedical application.