Making sense of disassembly

523-52

Disassembly of Dendritic Micellar Containers Due to Protein Binding

4550-

Site-Specific Installation and Study of Electroactive Units in Every Layer of Dendrons

While encapsulation of functional groups at the core of dendrimers is well-understood, very little is known about their intermediate layers or even the periphery. Here we report on a systematic investigation of every layer of dendrimers by incorporating a single ferrocene unit in well-defined locations in dendrons. Site-specific incorporation of the ferrocene unit was achieved utilizing the dendrimer sequencing methodology. We show here that the redox potential values of ferrocene at intermediate layers were remarkably different from that at the core and the periphery. While redox potential values were location-dependent, no significant change in the rate of heterogeneous electron transfer (k0) was observed with respect to locations. This was attributed to the possibility that free rotation of dendrimer nullifies the distance between the electrode and ferrocene unit. Finally, we also show that no Faradaic current was observed for the amphiphilic assemblies of these dendrons, while the same dendron did exhibit significant Faradaic current in non-assembling solvent environments

Photoregulated hydrazone-based hydrogel formation for biochemically patterning 3D cellular microenvironments

\u3cp\u3ePhotodriven click reactions have emerged as versatile tools for biomaterial synthesis that can recapitulate critical spatial and temporal changes of extracellular matrix (ECM) microenvironments in vitro. In this article, we report on the synthesis of poly(ethylene glycol) (PEG) hydrogels using photodriven step-growth polymerization, where one of the reactive functionalities is formed by a photocleavage reaction. Upon photocleavage, an aldehyde functionality is generated that rapidly reacts with hydrazine-functionalized PEGs; the gelation kinetics and final material modulus are distinctly controlled by variations in the light intensity. This light-driven aldehyde generation is further exploited to install biochemical ligands in the hydrazone-based hydrogels with precise spatial control. We expect that user-directed spatial and temporal control over both biophysical and biochemical gel properties through photochemical reactions and photopatterning, respectively, should provide newfound opportunities to probe and understand dynamic cell-matrix interactions.\u3c/p\u3

Selective peptide binding using facially amphiphilic dendrimers

11156-1116