Brain chemistry: A biosensor has been developed for in vivo determination of copper ions in a rat brain by using gold truncated octahedral microcages. The significant analytical performance of the present biosensor, as well as the properties of a carbon fiber microelectrode have provided a direct and reliable approach for monitoring cerebral metal ions (W.E.=working electrode; see picture).

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Direct determination of cerebral metal ions in small volume biological samples is still the bottleneck for evaluating the roles that metal ions play in the physiological and pathological processes. In this work, selected copper ion (Cu(2+)) as a model, a facile and direct electrochemical method for detection of Cu(2+) has been developed on the basis of two new designed strategies: one is specific recognition molecule for Cu(2+)-AE-TPEA (N-(2-aminoethyl)-N,N',N'-tris(pyridine-2-yl-methyl)ethane-1,2-diamine); another is carbon dots (C-Dots) with high electrocatalytic activity. Based on the high affinity between TPEA and Cu(2+), the electrode assembled with C-Dot-TPEA hybridized nanocomposites shows high selectivity toward Cu(2+) over other metal ions, amino acids, and biological coexisting species, such as uric acid (UA), ascorbic acid (AA), and so on, which makes it possible to be used for determination of Cu(2+) in the complex brain system. By taking advantage of C-Dots, a dynamic linear range from 1 μM to 60 μM is first achieved with a detection limit of ∼100 nM in aCSF solution. In addition, the developed method with theoretical simplicity and less instrumental demands exhibits long-term stability and good reproducibility. As a result, the present strategy has been successfully applied in detection of cerebral Cu(2+) in normal rat brain and that followed by global cerebral ischemia, combined with in vivo microdialysis. The determined concentrations of Cu(2+) in the rat brain microdialysates by the present method are found to be identical to those obtained by the conventional ICP-AES method.

A general Schiff-base strategy was developed to efficiently synthesize high-level N-doped porous carbons with tunable geometry and pore structure for supercapacitors.

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