scholarly journals Gold nanoparticles covalently assembled onto vesicle structures as possible biosensing platform

2016 ◽  
Vol 7 ◽  
pp. 655-663 ◽  
Author(s):  
M Fátima Barroso ◽  
M Alejandra Luna ◽  
Juan S Flores Tabares ◽  
Cristina Delerue-Matos ◽  
N Mariano Correa ◽  
...  

In this contribution a strategy is shown to covalently immobilize gold nanoparticles (AuNPs) onto vesicle bilayers with the aim of using this nanomaterial as platform for the future design of immunosensors. A novel methodology for the self-assembly of AuNPs onto large unilamellar vesicle structures is described. The vesicles were formed with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1-undecanethiol (SH). After, the AuNPs photochemically synthesized in pure glycerol were mixed and anchored onto SH–DOPC vesicles. The data provided by voltammetry, spectrometry and microscopy techniques indicated that the AuNPs were successfully covalently anchored onto the vesicle bilayer and decorated vesicles exhibit a spherical shape with a size of 190 ± 10 nm. The developed procedure is easy, rapid and reproducible to start designing a possible immunosensor by using environmentally friendly procedures.

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 173
Author(s):  
Marina Kurbasic ◽  
Ana M. Garcia ◽  
Simone Viada ◽  
Silvia Marchesan

Bioactive hydrogels based on the self-assembly of tripeptides have attracted great interest in recent years. In particular, the search is active for sequences that are able to mimic enzymes when they are self-organized in a nanostructured hydrogel, so as to provide a smart catalytic (bio)material whose activity can be switched on/off with assembly/disassembly. Within the diverse enzymes that have been targeted for mimicry, hydrolases find wide application in biomaterials, ranging from their use to convert prodrugs into active compounds to their ability to work in reverse and catalyze a plethora of reactions. We recently reported the minimalistic l-His–d-Phe–d-Phe for its ability to self-organize into thermoreversible and biocatalytic hydrogels for esterase mimicry. In this work, we analyze the effects of terminus modifications that mimic the inclusion of the tripeptide in a longer sequence. Therefore, three analogues, i.e., N-acetylated, C-amidated, or both, were synthesized, purified, characterized by several techniques, and probed for self-assembly, hydrogelation, and esterase-like biocatalysis. This work provides useful insights into how chemical modifications at the termini affect self-assembly into biocatalytic hydrogels, and these data may become useful for the future design of supramolecular catalysts for enhanced performance.


Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1772 ◽  
Author(s):  
Maria de los Angeles Cortes ◽  
Raquel de la Campa ◽  
Maria Luisa Valenzuela ◽  
Carlos Díaz ◽  
Gabino A. Carriedo ◽  
...  

During the last number of years a variety of crystallization-driven self-assembly (CDSA) processes based on semicrystalline block copolymers have been developed to prepare a number of different nanomorphologies in solution (micelles). We herein present a convenient synthetic methodology combining: (i) The anionic polymerization of 2-vinylpyridine initiated by organolithium functionalized phosphane initiators; (ii) the cationic polymerization of iminophosphoranes initiated by –PR2Cl2; and (iii) a macromolecular nucleophilic substitution step, to prepare the novel block copolymers poly(bistrifluoroethoxy phosphazene)-b-poly(2-vinylpyridine) (PTFEP-b-P2VP), having semicrystalline PTFEP core forming blocks. The self-assembly of these materials in mixtures of THF (tetrahydrofuran) and 2-propanol (selective solvent to P2VP), lead to a variety of cylindrical micelles of different lengths depending on the amount of 2-propanol added. We demonstrated that the crystallization of the PTFEP at the core of the micelles is the main factor controlling the self-assembly processes. The presence of pyridinyl moieties at the corona of the micelles was exploited to stabilize gold nanoparticles (AuNPs).


Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 993 ◽  
Author(s):  
Baoyan Wu ◽  
Shihua Hou ◽  
Yongyong Xue ◽  
Zhan Chen

The study reports a facile and eco-friendly approach for nanomaterial synthesis and enzyme immobilization. A corresponding glucose biosensor was fabricated by immobilizing the gold nanoparticles (AuNPs) and glucose oxidase (GOD) multilayer films onto the polypyrrole (PPy)/reduced graphene oxide (RGO) modified glassy carbon electrode (GCE) via the electrodeposition and self-assembly. PPy and graphene oxide were first coated on the surface of a bare GCE by the electrodeposition. Then, AuNPs and GOD were alternately immobilized onto PPy-RGO/GCE electrode using the electrodeposition of AuNPs and self-assembly of GOD to obtain AuNPs-GOD multilayer films. The resulting PPy-RGO-(AuNPs-GOD)n/GCE biosensors were used to characterize and assess their electrocatalytic activity toward glucose using cyclic voltammetry and amperometry. The response current increased with the increased number of AuNPs-GOD layers, and the biosensor based on four layers of AuNPs-GOD showed the best performance. The PPy-RGO-(AuNPs-GOD)4/GCE electrode can detect glucose in a linear range from 0.2 mM to 8 mM with a good sensitivity of 0.89 μA/mM, and a detection limit of 5.6 μM (S/N = 3). This study presents a promising eco-friendly biosensor platform with advantages of electrodeposition and self-assembly, and would be helpful for the future design of more complex electrochemical detection systems.


2014 ◽  
Vol 50 (85) ◽  
pp. 12933-12936 ◽  
Author(s):  
Clara Morita-Imura ◽  
Yoshiro Imura ◽  
Takeshi Kawai ◽  
Hitoshi Shindo

The pH-responsive self-assembly of a zwitterionic amphiphile was expanded to the recovery of gold (Au) nanoparticles. Multilayered lamellae were incorporated into the nanoparticles. Redispersion of nanoparticles was achieved by the transition of self-assembly based on pH.


2013 ◽  
Vol 49 (69) ◽  
pp. 7617 ◽  
Author(s):  
Boram Kim ◽  
Sung-ju Choi ◽  
So-hee Han ◽  
Kang-Yell Choi ◽  
Yong-beom Lim

2014 ◽  
Vol 16 (36) ◽  
pp. 19402-19407 ◽  
Author(s):  
Harekrishna Ghosh ◽  
Ahmed Bouhekka ◽  
Thomas Bürgi

Germanium modified with gold nanoparticles shows a drastically increased concentration of holes near the valence band edge upon illumination with visible or near infrared light.


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