3 research outputs found
Zinc Photocages with Improved Photophysical Properties and Cell Permeability Imparted by Ternary Complex Formation
Photocaged complexes have demonstrated efficacy as tools to control the
availability of bioactive metals in cells to interrogate signaling pathways. We
describe the synthesis of two new photocages, {bis[(2-pyridyl)methyl]amino}(9-oxo-2-xanthenyl)acetic
acid (XDPAdeCage, 1) {bis[(2-pyridyl)methyl]amino}(m-nitrophenyl)acetic acid (DPAdeCage, 2), which utilize a 4-xanthone acetic acid and meta-nitrobenzyl chromophore respectively, to mediate a
photodecarboxylation reaction. Both photocages strongly coordinate Zn2+
and the binding equilibrium shifts significantly toward free Zn2+
upon the decarboxylation of the chelator. XDPAdeCage photolyzes with quantum
yield of 27% with 365 nm light, and binds Zn2+ with 4.6 pM affinity,
which decreases by over 4 orders of magnitude upon uncaging. A neutral form of [Zn(XDPAdeCage)]+
can be generated in situ using the
anionic bidentate ligand pyrithione, which imparts membrane impermeability to
the ternary complex. Using fluorescent imaging, we have confirmed transport of
Zn2+ across lipophilic membranes; in addition, RT-PCR experiments
demonstrate the photocaged complexes ability to perturb cellular processes
after photolysis by showing a change in the expression levels of
metallothionein and zinc transporter proteins
Digital circuits and neural networks based on acid-base chemistry implemented by robotic fluid handling
The complementarity of acids and bases is a fundamental chemical concept. Here, the authors use simple acid-base chemistry to encode binary information and perform information processing including digital circuits and neural networks using robotic fluid handling