Layer-by-layer self-assembly, controllable disintegration of polycarboxybetaine multilayers and preparation of free-standing films at physiological conditions

2010 ◽  
Vol 20 (8) ◽  
pp. 1467-1474 ◽  
Author(s):  
Zhangliang Gui ◽  
Jinwen Qian ◽  
Quanfu An ◽  
Qiang Zhao ◽  
Huangtao Jin ◽  
...  
2009 ◽  
Vol 81 (12) ◽  
pp. 2225-2233 ◽  
Author(s):  
Xing Yi Ling ◽  
David N. Reinhoudt ◽  
Jurriaan Huskens

Fabricating well-defined and stable nanoparticle crystals in a controlled fashion receives growing attention in nanotechnology. The order and packing symmetry within a nanoparticle crystal is of utmost importance for the development of materials with unique optical and electronic properties. To generate stable and ordered 3D nanoparticle structures, nanotechnology is combined with supramolecular chemistry to control the self-assembly of 2D and 3D receptor-functionalized nanoparticles. This review focuses on the use of molecular recognition chemistry to establish stable, ordered, and functional nanoparticle structures. The host–guest complexation of β-cyclodextrin (CD) and its guest molecules (e.g., adamantane and ferrocene) are applied to assist the nanoparticle assembly. Direct adsorption of supramolecular guest- and host-functionalized nanoparticles onto (patterned) CD self-assembled monolayers (SAMs) occurs via multivalent host–guest interactions and layer-by-layer (LbL) assembly. The reversibility and fine-tuning of the nanoparticle-surface binding strength in this supramolecular assembly scheme are the control parameters in the process. Furthermore, the supramolecular nanoparticle assembly has been integrated with top-down nanofabrication schemes to generate stable and ordered 3D nanoparticle structures, with controlled geometries and sizes, on surfaces, other interfaces, and as free-standing structures.


Author(s):  
Greeshma Chathamkandath Raghuvaran ◽  

Nanoscale graphene oxide-lipid composites have shown wide applications in the field of biosensing and nanosafety. Macroscopic free-standing membranes of this combination potentially offer excellent mechanical properties which can be attributed to the inherent strength of graphene oxide(GO). Previous experimental studies have mostly dealt with monolayer or bilayer interactions of lipids with graphene and graphene oxide surfaces. In our study, we report for the first time, a simple and scalable fabrication method where Small Unilamellar Vesicles (SUVs) of 1,2-dioleoyl-sn-glycero-3-phosphocholine(DOPC) combine with graphene oxide to produce stable nanocomposites via self-assembly. Scanning Electron Microscopy (SEM) images of the composite revealed layer-by-layer structures, reconfirmed by X-Ray Diffraction(XRD) results which show a proportional increase in the interlayer separation with an increasing ratio of lipid in graphene oxide. The nanocomposite thus fabricated mimics naturally occurring nacre shell structures where graphene oxide substitutes the strong aragonite layers, and the intermediate lipid layers provide the necessary elasticity pertaining to protein chitin in nacre. The addition of lipids to graphene-based nanocomposites also serves as a biodegradable alternative to using polymers as a popular reinforcement agent. The ease of fabrication method reported facilitates the production of stable GO-Lipid membranes in variable scales and geometries.


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1884
Author(s):  
Mengfei Jin ◽  
Shangyong Li ◽  
Yanhong Wu ◽  
Dandan Li ◽  
Yantao Han

(1) Background: In the treatment of ulcerative colitis (UC), accurate delivery and release of anti-inflammatory drugs to the site of inflammation can reduce systemic side effects. (2) Methods: We took advantage of this goal to prepare resveratrol-loaded PLGA nanoparticles (RES-PCAC-NPs) by emulsification solvent volatilization. After layer-by-layer self-assembly technology, we deposited chitosan and alginate to form a three-layer polyelectrolyte film. (3) Results: It can transport nanoparticles through the gastric environment to target inflammation sites and slowly release drugs at a specific pH. The resulting RES-PCAC-NPs have an ideal average diameter (~255 nm), a narrow particle size distribution and a positively charged surface charge (~13.5 mV). The Fourier transform infrared spectroscopy showed that resveratrol was successfully encapsulated into PCAC nanoparticles, and the encapsulation efficiency reached 87.26%. In addition, fluorescence imaging showed that RES-PCAC-NPs with positive charges on the surface can effectively target and accumulate in the inflammation site while continuing to penetrate downward to promote mucosal healing. Importantly, oral RES-PCAC-NPs treatment in DSS-induced mice was superior to other results in significantly improved inflammatory markers of UC. (4) Conclusions: Our results strongly prove that RES-PCAC-NPs can target the inflamed colon for maximum efficacy, and this oral pharmaceutical formulation can represent a promising formulation in the treatment of UC.


2014 ◽  
Vol 14 (2) ◽  
pp. 1145-1153 ◽  
Author(s):  
Bing Yu ◽  
Xiaomian Liu ◽  
Hailin Cong ◽  
Hua Yuan ◽  
Dong Wang ◽  
...  
Keyword(s):  

2010 ◽  
Vol 46 (9) ◽  
pp. 1434 ◽  
Author(s):  
Meng Yang ◽  
Shanfu Lu ◽  
Jinlin Lu ◽  
San Ping Jiang ◽  
Yan Xiang

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 515
Author(s):  
Tongfang Liu ◽  
Song Rui ◽  
Sheng Li

Mg alloys are promising biomedical metal due to their natural degradability, good processability, and favorable mechanical properties. However, the poor corrosion resistance limits their further clinical applications. In this study, the combined strategies of surface chemical treatment and layer-by-layer self-assembly were used to prepare composite coatings on Mg alloys to improve the biocorrosion resistance. Specially, alkalized AZ91 Mg alloy generated chemical linkage with silane via Si–O–Mg covalent bond at the interface. Subsequently, Si–OH group from silane formed a crosslinked silane layer by Si–O–Si network. Further chemical assembly with graphene oxide (GO), lengthened the diffusion pathway of corrosive medium. The chemically assembled composite coatings could firmly bond to Mg alloy substrate, which persistently and effectively acted as compact barriers against corrosion propagation. Improved biocorrosion resistance of AZ91 Mg alloy with self-assembly composite coatings of silane/GO was subsequently confirmed by immersion tests. Besides, the Mg alloy exhibited good wear resistance due to outside layer of GO with a lubricant effect. Cell viability of higher than 75% had also been found for the alloy with self-assembly composite coatings, which showed good cytocompatibility.


Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 13 ◽  
Author(s):  
Bin Zhang ◽  
Jaehyun Lee ◽  
Mincheol Kim ◽  
Naeeung Lee ◽  
Hyungdong Lee ◽  
...  

The macroscopic assembly of two-dimensional materials into a laminar structure has received considerable attention because it improves both the mechanical and chemical properties of the original materials. However, conventional manufacturing methods have certain limitations in that they require a high temperature process, use toxic solvents, and are considerably time consuming. Here, we present a new system for the self-assembly of layer-by-layer (LBL) graphene oxide (GO) via an electrohydrodynamic (EHD) jet printing technique. During printing, the orientation of GO flakes can be controlled by the velocity distribution of liquid jet and electric field-induced alignment spontaneously. Closely-packed GO patterns with an ordered laminar structure can be rapidly realized using an interfacial assembly process on the substrates. The surface roughness and electrical conductivity of the LBL structure were significantly improved compared with conventional dispensing methods. We further applied this technique to fabricate a reduced graphene oxide (r-GO)-based supercapacitor and a three-dimensional (3D) metallic grid hybrid ammonia sensor. We present the EHD-assisted assembly of laminar r-GO structures as a new platform for preparing high-performance energy storage devices and sensors.


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