Carboxylatopillar[5]arene Functionalized C-Dots And Core-shell Nanoparticles For Sensing And Controlled Drug Release

Organic supramolecular chemistry based on macrocyclic compounds is a research discipline that studies the molecular recognition and assembly of macrocyclic receptors and the functions of assemblies,where the design and synthesis of macrocyclic compounds is the cornerstone.Pillar[n]arenes(pillarenes)represent a new class of novel supramolecular macrocycle hosts after crown ethers,cyclodextrins,calixarenes,cucurbiturils,etc.,that have been recently discovered and attracted more and more attentions from supramolecular chemists with great potentials.Due to the symmetrical rigid structures,tunable cavity sizes,hydrophobic and electron-rich cavities,facile synthesis and functionalization,and the distinctive host-guest interactions,pillarenes have been gradually applied in many research fields including drug delivery,ion channels,catalysis,adsorption and separation,sensing and detection,and optoelectronic materials.Moreover,benefiting from the attractive host-guest properties,pillarenes are receiving more and more interest in terms of their use in the construction of functional nanosystems.On the above basis,we design and synthesize two nanosupramolecular systems based on pillarenes,one is a new fluorescent sensor platform based on pillarenes modified CN-dots,the other is a stimuli-responsive chemo-photothermo synergistic theranostic nanosystem gated by pillarenes.In the first part,we prepared a novel fluorescent sensing platform based on pillarenes.N doped C-dots(CN-dots)were conjugated with carboxylatopillar[5]arene(CP[5])through amidation reaction to give the CP[5] modified CN-dots,namely CCDs.Compared with the non-CP[5]-modified CN-dots,the newly constructed CCDs with pillararene blocks could detect Fe3+ with high selectivity.Therefore,such CCDs can serve as a novel chemical sensor for the detection of Fe3+.In the second part,we employed carboxylatopillar[5]arene sodium salt(CP[5] sodium salt)as a gating entity to construct supramolecular nanovalves on the surface of the core-shell nanocomposites consisting of MOFs(MIL-101(Fe)-NH2)coated gold nanorods(Au NRs),and obtained a smart core-shell theranostic nanosystem(Au MC)capable of photothermal therapy and stimuli-responsive drug release.The prepared Au MC nanocomposites possess the abilities of decent X-ray imaging,good biocompatibility,photothermal therapy,and highly efficient drug delivery,and could further realize the controlled drug release in response to external environmental changs,such as temperature,p H,and the concentration of Ca2+.Compared with the nanocomposites without nanovalves,Au MC exhibited outstanding drug loading effect,multi-stimuli-responsive and sustainable release ability.The experimental results indicated that the Au MC nanocarrier possesses great potential in X-ray imaging-guided multi-stimuli-responsive cancer therapy.