Yan Wang,Wei Liu,Ruitian Guo,Qunting Qu,Honghe Zheng,Jingyu Zhang,Yunhui Huang
Renewable lithium-ion batteries based on green organic lithium storage materials are of great significance for sustainable development of new power sources. Herein, itaconic acid, with two active carboxyl groups and a conjugated double bond, is proposed for lithium storage purposes. During electrode processing with carboxymethyl cellulose sodium and styrene butadiene rubber binders, itaconic acid assembles into a leek-like morphology composed of ultrathin micro-ribbons. Self-assembled morphological transformation from the leek-like ribbon to an amorphous state and finally to micro-spheres at different electrochemical states is observed. It is capable of reacting reversibly with six lithium ions per formula unit, exhibiting the first reversible capacity of 1270 mA h g−1. Moreover, the first coulombic efficiency, rate capability and cycling stability are superior to those of most of the reported organic materials. The underlying mechanisms of lithiation and de-lithiation are discussed through a combination of electrochemical and spectroscopic studies.
To develop a smart nanovalve on mesoporous silica nanoparticles (MSNs) for biomedical applications, a new type of peptide-functionalized MSN with a plug-gate nanovalve (PGN) was designed for targeted drug release in cancer cells. The outer shell of MSN was functionalized with K8 peptide (octa-lysine sequence) by click chemistry, followed by reacting with citraconic anhydride via α,β-unsaturated bond to prepare negatively charged MSN–K8(Cit). Subsequently, a cationic K8(RGD)2 peptide containing two Arg–Gly–Asp (RGD) sequences for targeting was introduced via electrostatic interaction to the negatively charged surface of MSN–K8(Cit) to form PGN. It was found that, at pH 5.0 (simulating the endo/lysosomal environment), the surface charge of MSN–K8(Cit) could convert from −41 mV to +19 mV due to the hydrolysis of the acid-labile amides in the acidic condition, implying the subsequent electrostatic repulsion to induce opening of the nanovalves and release of anticancer drug, DOX. According to the drug release studies, 79% of DOX was released within 48 h at pH 5.0, while much less DOX was released at pH 6.5 and 7.4. Furthermore, in vitro cellular experiments confirmed that the drug delivery system had enhanced cellular association and cell inhibition effect on αvβ3-positive U87 MG cancerous cells.
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