Inside Cover: Facile, Template‐Free Synthesis of Stimuli‐Responsive Polymer Nanocapsules for Targeted Drug Delivery (Angew. Chem. Int. Ed. 26/2010)

Abstract

Open Sesame! A template-free synthetic approach to stimuli-responsive polymer nanocapsules that are potentially useful for targeted drug delivery has been developed. In their Communication on p. 4405 ff., K. Kim and co-workers show that reductively labile polymer nanocapsules composed of CB[6] and disulfide bridges allow not only facile, noncovalent surface modification for targeted delivery but also the release of encapsulated cargo in response to a predefined redox stimulus in an intracellular environment.

Synthesis of Star Poly(N-isopropylacrylamide) with a Core of Cucurbit[6]uril via ATRP and Controlled Thermoresponsivity

“…[ 36 ] The PNIPAM chains were grown from the CB [6]based macroinitiator by the method of ATRP as shown in Scheme 1 a. This was done in a two-step procedure: (1) synthesis of the CB [6]-based macroinitiator by acylation reaction between 2-bromopropionyl bromide and (OH) 12 CB [6], and (2) ATRP of NIPAM from CB[6]-based macroinitiator.…”

“…The CB [6]-based macroinitiator with "n" bromo-initiation sites on the "equator" of CB [6] were obtained by acylation reaction of 2-bromopropionyl bromide with hydroxyl groups of (OH) 12 CB [6] (Scheme 1 a). Generally speaking, all the hydroxyl groups may react with 2-bromopropionyl bromide during the acylation process.…”

“…In a typical experiment, [ 15,21 ] 4-(dimethylamino) pyridine (0.0117 g, 9.6 mmol) was dissolved in 20 mL of N , N -dimethylacetamide (DMA) at room temperature, and (OH) 12 CB [6] (1.3005 g, 0.8 mmol) was added to the solution. After triethylamine (1.1131 g, 11 mmol) and 2-bromopropionyl bromide (2.3746 g, 11 mmol) were added dropwise at 0 °C under nitrogen atmosphere, the reaction mixture was stirred for 16 h at room temperature.…”

“…An apparent advantage of CB [6]-anchored polymers is the appearance of CB [6] cavity on the polymer backbone, which can construct noncovalently connected polymeric architectures by supramolecular complexation. [11][12][13][14][15][16] Moreover, the incorporation the star-like PNIPAM was signifi cantly different in comparison to linear PNIPAM polymers. [ 33 ] Construction of CB [6] containing star-like PNIPAM could expand the category of useful polymers, enable the study of structureproperty relationships of novel species and endow the polymer with new properties that would be of benefi t in challenging applications.…”

“…[ 17 ] All these fascinating properties of CB[6]-anchored polymers would be useful in supramolecular chemistry, analytical studies, separation technology, macromolecular machines, smart materials, and pharmaceutical applications. [12][13][14]16,[18][19][20][21][22][23] Thermoresponsive polymers are an important class of materials, [24][25][26] which often show strong and reversible phase transitions in response to small temperature changes. The widely used poly(N-isopropylacrylamide) (PNIPAM) is one of the most popular thermoresponsive polymers, which shows dramatic and reversible phase transition behavior with the lower critical solution temperature (LCST) at 32 °C.…”