Control of surface functionality in the synthesis of dendritic macromolecules using the convergent-growth approach

1990 ◽  
Vol 23 (21) ◽  
pp. 4726-4729 ◽  
Author(s):  
Craig J. Hawker ◽  
J. M. J. Frechet
2018 ◽  
Author(s):  
Pierre Marcasuzaa ◽  
Samuel Pearson ◽  
Karell Bosson ◽  
Laurence Pessoni ◽  
Jean-Charles Dupin ◽  
...  

A hierarchically structured platform was obtained from spontaneous self-assembly of a poly(styrene)-<i>b</i>-poly(vinylbenzylchloride) (PS-<i>b</i>-PVBC) block copolymer (BCP) during breath figure (BF) templating. The BF process using a water/ethanol atmosphere gave a unique double porosity in which hexagonally arranged micron-sized pores were encircled by a secondary population of smaller, nano-sized pores. A third level of structuration was simultaneously introduced between the pores by directed BCP self-assembly to form out-of-the-plane nano-cylinders, offering very rapid bottom-up access to a film with unprecedented triple structure which could be used as a reactive platform for introducing further surface functionality. The surface nano-domains of VBC were exploited as reactive nano-patterns for site-specific chemical functionalization by firstly substituting the exposed chlorine moiety with azide, then “clicking” an alkyne by copper (I) catalyzed azide-alkyne Huisgen cycloaddition (CuAAC). Successful chemical modification was verified by NMR spectroscopy, FTIR spectroscopy, and XPS, with retention of the micro- and nanostructuration confirmed by SEM and AFM respectively. Protonation of the cyclotriazole surface groups triggered a switch in macroscopic behavior from a Cassie-Baxter state to a Wenzel state, highlighting the possibility of producing responsive surfaces with hierarchical structure.


Carbon ◽  
2000 ◽  
Vol 38 (5) ◽  
pp. 669-674 ◽  
Author(s):  
H Benaddi ◽  
T.J Bandosz ◽  
J Jagiello ◽  
J.A Schwarz ◽  
J.N Rouzaud ◽  
...  

2020 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Eduardo Ravelo-Nieto ◽  
Alvaro Duarte-Ruiz ◽  
Luis H. Reyes ◽  
Juan C. Cruz

Several biological barriers are generally responsible for the limited delivery of cargoes at the cellular level. Fullerenols have unique structural features and possess suitable properties for interaction with the cells. This study aimed to synthesize and characterize a fullerenol derivative with desirable characteristics (size, charge, functionality) to develop cell penetration vehicles. Fullerenol was synthesized from fullerene (C60) solubilized in toluene, followed by hydroxylation with hydrogen peroxide and tetra-n-butylammonium hydroxide (TBAH) as a phase transfer catalyst. The obtained product was purified by a Florisil chromatography column (water as the eluent), followed by dialysis (cellulose membrane dialysis tubing) and freeze-drying (yield 66%). Subsequently, a silane coupling agent was conjugated on the fullerenol surface to render free amine functional groups for further covalent functionalization with other molecules. Characterization via UV–VIS, FTIR-ATR, Raman, DLS, and SEM techniques was conducted to evaluate the composition, size, morphology, surface functionality, and structural properties. We are currently working on the conjugation of the potent cell-penetrating agents Buforin II (BUFII) and the Outer Membrane Protein A (OmpA) on the surface of the fullerenol to estimate whether cell penetration and endosome escape are improved concerning conventional polymeric vehicles and our previous developments with iron oxide nanoparticles.


Author(s):  
Ali El-Naggar ◽  
Sabry M. Shaheen ◽  
Scott X. Chang ◽  
Deyi Hou ◽  
Yong Sik Ok ◽  
...  

2021 ◽  
pp. 129405
Author(s):  
Nisha Singh ◽  
Nitin Khandelwal ◽  
Zahid Ahmad Ganie ◽  
Ekta Tiwari ◽  
Gopala Krishna Darbha

MRS Advances ◽  
2016 ◽  
Vol 1 (29) ◽  
pp. 2099-2106 ◽  
Author(s):  
M. Parvinzadeh Gashti ◽  
M. Zarabadi ◽  
J. Greener

ABSTRACTThe biomass accumulation and movement of biofilms in a microchannel is monitored by optical microscopy. First, the average optical density of the biofilm is monitored in time as a measure of biofilm thickness and structural heterogeneity. These results are used as inputs to calculate changing flow velocities due to resulting excluded volume. Next the displacement velocity of moving biofilm segments was recorded in different places in the microchannel. Quantitative analysis by a particle tracking routine showed differences in displacement velocity near and far from the microchannel corner, which is believed to be related to the local shear forces which vary depending on the height of the biofilm segment and its position in the microchannel. The effect of changing biofilm thickness and different hydrodynamic environments in the microchannel are then discussed in terms of their effects on molecular loading rates. Finally, a demonstration of a flow-templated growth approach as a means to homogenize the growth environment.


2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Changixu Cheng ◽  
Xiaomei Song ◽  
Jing Yang ◽  
Xiatian Hu ◽  
Shi Shen ◽  
...  

This paper addresses a special zone design problem for economic census investigators that is motivated by a real-world application. This paper presented a heuristic multikernel growth approach via Constrained Delaunay Triangulation (CDT). This approach not only solved the barriers problem but also dealt with the polygon data in zoning procedure. In addition, it uses a new heuristic method to speed up the zoning process greatly on the premise of the required quality of zoning. At last, two special instances for economic census were performed, highlighting the performance of this approach.


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