A near-infrared-emission aza-BODIPY-based fluorescent probe for fast, selective, and "turn-on" detection of HClO/ClO.

A novel near-infrared-emitting aza-BODIPY-based fluorescent probe with two tellurium atoms at two upper benzyl rings has been prepared and explored for its fluorescent sensing properties towards hypochlorous acid/hypochorite (HClO/ClO-), which showed high selectivity and absolutely fluorescent "turn-on" phenomenon at 738 nm. The fluorescence of this probe was sufficiently quenched due to photoindued electron transfer by two tellurium atoms. Upon exposure to HClO/ClO-, a strong near-infrared emission at 738 nm appeared with fluorescence quantum yields changing from 0 to 0.11. This remarkable fluorescence change was ascribed to the oxidation of both electron-rich tellurium atoms. The detection limit of this probe towards HClO/ClO- was calculated to 0.09 µM in acetonitrile aqueous solution by the linear fluorescence change at 738 nm in the HClO/ClO--concentration range of 0-30 µM. Interestingly, this probe was found to be applicable in a broad pH range (2-10). Meanwhile, the oxidized probe could be further responsive to biothiols with substantial fluorescence disappearance. The bioimaging experiments in RAW264.7 cells showed the appearance of intracellular near-infrared fluorescence after addition of HClO/ClO- and PMA, and the fluorescence could also be reversed to be silenced by further introduction of GSH, confirming its potential application for exogenous and endogenous detection of HClO/ClO- in living cells.

Ultrahigh-Density 256-Channel Neural Sensing Microsystem Using TSV-Embedded Neural Probes.

Highly integrated neural sensing microsystems are crucial to capture accurate signals for brain function investigations. In this paper, a 256-channel neural sensing microsystem with a sensing area of 5 × 5 mm 2 is presented based on 2.5-D through-silicon-via (TSV) integration. This microsystem composes of dissolvable µ-needles, TSV-embedded µ-probes, 256-channel neural amplifiers, 11-bit area-power-efficient successive approximation register analog-to-digital converters, and serializers. This microsystem can detect 256 electrocorticography and local field potential signals within a small area of 5 mm × 5 mm. The neural amplifier realizes 57.8 dB gain with only 9.8 µW per channel. The overall power of this microsystem is only 3.79 mW for 256-channel neural sensing. A smaller microsystem with dimension of 6 mm × 4 mm has been also implanted into rat brain for somatosensory evoked potentials (SSEPs) recording by using contralateral and ipsilateral electrical stimuli with intensity from 0.2 to 1.0 mA, and successfully observed different SSEPs from left somatosensory cortex of a rat.