Light-Responsive Polyion Complex Micelles with Switchable Surface Charge for Efficient Protein Delivery.

In this letter, light-responsive protein-encapsulated polyion complex (PIC) micelles were prepared by self-assembly of cationic block copolymer poly(,-dimethyl--(2-(methacryloyloxy)ethyl)--((2-nitrobenzyl)oxy)-2-oxoethanaminium bromide)--poly(carboxybetaine methacrylate) (PDMNBMA--PCBMA) and negatively charged bovine serum albumin (BSA). The PIC micelles were well characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). From the zeta potential measurement, the increase of the zeta potential of PIC micelles from ∼10 to ∼20 mV was observed when the solution pH decreased from 7.

Light and pH dual-degradable triblock copolymer micelles for controlled intracellular drug release.

A novel amphiphilic ABA-type triblock copolymer poly(ethylene glycol)-b-poly(ethanedithiol-alt-nitrobenzyl)-b-poly(ethylene glycol) (PEG-b-PEDNB-b-PEG) is successfully prepared by sequential thiol-acrylate Michael addition polymerization in one pot. PEG-b-PEDNB-b-PEG is designed to have light-cleavable o-nitrobenzyl linkages and acid-labile β-thiopropionate linkages positioned repeatedly in the main chain of the hydrophobic block. The light and pH dual degradation of PEG-b-PEDNB-b-PEG is traced by gel permeation chromatography (GPC).

1-[(5-Bromo-pent-yloxy)meth-yl]pyrene.

In the title compound, C(22)H(21)BrO, other than the Br atom, the non-H atoms are approximately co-planar [maxium deviation = 0.178 (2) Å] and the alk-oxy chain shows an all-anti conformation. A weak inter-molecular C-H⋯Br hydrogen bond contributes to the stabilization of the crystal structure.

5,6-Dihydro-2H-1,3-dithiolo[4,5-b][1,4]dioxine-2-thione.

The title mol-ecule, C(5)H(4)O(2)S(3), consists of a planar [mean deviation = 0.020 (1) Å] 1,3-dithiole-2-thione unit with an ethyl-enedi-oxy group in the 4,5-positions. The dioxine ring is in a twist-chair conformation.