Monoliths of nanoporous gold (np-Au) were modified with self-assembled monolayers of octadecanethiol (C-SH), 8-mercaptooctyl α-D-mannopyranoside (αMan-C-SH), and 8-mercapto-3,6-dioxaoctanol (HO-PEG-SH), and the loading was assessed using thermogravimetric analysis (TGA). Modification with mixed SAMs containing αMan-C-SH (at a 0.20 mole fraction in the SAM forming solution) with either octanethiol or HO-PEG-SH was also investigated. The np-Au monoliths modified with αMan-C-SH bind the lectin Concanavalin A (Con A), and the additional mass due to bound protein was assessed using TGA analysis. A comparison of TGA traces measured before and after exposure of HO-PEG-SH modified np-Au to Con A showed that the non-specific binding of Con A was minimal. In contrast, np-Au modified with octanethiol showed a significant mass loss due to non-specifically adsorbed Con A. A significant mass loss was also attributed to binding of Con A to bare np-Au monoliths. TGA revealed a mass loss due to the binding of Con A to np-Au monoliths modified with pure αMan-C-SH. The use of mass losses determined by TGA to compare the binding of Con A to np-Au monoliths modified by mixed SAMs of αMan-C-SH and either octanethiol or HO-PEG-SH revealed that binding to mixed SAM modified surfaces is specific for the mixed SAMs with HO-PEG-SH but shows a significant contribution from non-specific adsorption for the mixed SAMs with octanethiol. Minimal adsorption of immunoglobulin G (IgG) and peanut agglutinin (PNA) towards the mannoside modified np-Au monoliths was demonstrated. A greater mass loss was found for Con A bound onto the monolith than for either IgG or PNA, signifying that the mannose presenting SAMs in np-Au retain selectivity for Con A. TGA data also provide evidence that Con A bound to the αMan-C-SH modified np-Au can be eluted by flowing a solution of methyl α--mannopyranoside through the structure. The presence of Con A proteins on the modified np-Au surface was also confirmed using atomic force microscopy (AFM). The results highlight the potential for application of carbohydrate modified np-Au monoliths to glycoscience and glycotechnology and demonstrate that they can be used for capture and release of carbohydrate binding proteins in significant quantities.
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http://dx.doi.org/10.1039/C3NJ00253E | DOI Listing |
Nanomaterials (Basel)
January 2021
Department of Chemistry and Biochemistry, University of Missouri-St. Louis, Saint Louis, MO 63121, USA.
Nanoparticles (NPs) have been widely explored for delivering doxorubicin (DOX), an anticancer drug, to minimize cardiotoxicity. However, their efficiency is marred by a necessity to chemically modify DOX, NPs, or both and low deposition of the administered NPs on tumors. Therefore, alternative strategies should be developed to improve therapeutic efficacy and decrease toxicity.
View Article and Find Full Text PDFAdv Mater
March 2020
Key Laboratory of Automobile Materials (Jilin University), Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun, 130022, China.
Designing highly active and robust electrocatalysts for oxygen evolution reaction (OER) is crucial for many renewable energy storage and conversion devices. Here, self-supported monolithic hybrid electrodes that are composed of bimetallic cobalt-molybdenum nitride nanosheets vertically aligned on 3D and bicontinuous nanoporous gold (NP Au/CoMoN ) are reported as highly efficient electrocatalysts to boost the sluggish reaction kinetics of water oxidation in alkaline media. By virtue of the constituent CoMoN nanosheets having large accessible CoMoO surface with remarkably enhanced electrocatalytic activity and the nanoporous Au skeleton facilitating electron transfer and mass transport, the NP Au/CoMoN electrode exhibits superior OER electrocatalysis in 1 m KOH, with low onset overpotential (166 mV) and Tafel slope (46 mV dec ).
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2017
Department of Photonics, ‡Center for Micro/Nano Science and Technology (CMNST), and §Advanced Optoelectronics Technology Center (AOCT), National Cheng Kung University, Tainan 701, Taiwan.
A robust and recyclable monolithic substrate applying all-inorganic metal-oxide selective contact with a nanoporous (np) Au:NiO counter electrode is successfully demonstrated for efficient perovskite solar cells, of which the perovskite active layer is deposited in the final step for device fabrication. Through annealing of the Ni/Au bilayer, the nanoporous NiO/Au electrode is formed in virtue of interconnected Au network embedded in oxidized Ni. By optimizing the annealing parameters and tuning the mesoscopic layer thickness (mp-TiO and mp-AlO), a decent power conversion efficiency (PCE) of 10.
View Article and Find Full Text PDFJ Chromatogr A
December 2015
Department of Chemistry and Biochemistry, One University Boulevard, University of Missouri-St. Louis, Saint Louis, MO 63121 USA; Center for Nanoscience, One University Boulevard, University of Missouri-St. Louis, Saint Louis, MO 63121, USA. Electronic address:
The surface of nanoporous gold (np-Au) monoliths was modified via a flow method with the lectin Concanavalin A (Con A) to develop a substrate for separation and extraction of glycoproteins. Self-assembled monolayers (SAMs) of α-lipoic acid (LA) on the np-Au monoliths were prepared followed by activation of the terminal carboxyl groups to create amine reactive esters that were utilized in the immobilization of Con A. Thermogravimetric analysis (TGA) was used to determine the surface coverages of LA and Con A on np-Au monoliths which were found to be 1.
View Article and Find Full Text PDFACS Nano
February 2015
Nanoscale Synthesis and Characterization Laboratory, Lawrence Livermore National Laboratory , 7000 East Avenue, Livermore, California 94550, United States.
Much progress has recently been made in the development of active materials, electrode morphologies and electrolytes for lithium ion batteries. Well-defined studies on size effects of the three-dimensional (3D) electrode architecture, however, remain to be rare due to the lack of suitable material platforms where the critical length scales (such as pore size and thickness of the active material) can be freely and deterministically adjusted over a wide range without affecting the overall 3D morphology of the electrode. Here, we report on a systematic study on length scale effects on the electrochemical performance of model 3D np-Au/TiO2 core/shell electrodes.
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