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Title: Multifunctional Fe 2 O 3 –Au Nanoparticles with Different Shapes: Enhanced Catalysis, Photothermal Effects, and Magnetic Recyclability

Authors:
; ;
Publication Date:
Research Org.:
SRS
Sponsoring Org.:
USDOE
OSTI Identifier:
1348899
Report Number(s):
SRNL-STI-2016-00325
Journal ID: ISSN 1932-7447
DOE Contract Number:
DE-AC09-08SR22470
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. C; Journal Volume: 120; Journal Issue: 28
Country of Publication:
United States
Language:
English

Citation Formats

Larsen, George K., Farr, Will, and Hunyadi Murph, Simona E. Multifunctional Fe 2 O 3 –Au Nanoparticles with Different Shapes: Enhanced Catalysis, Photothermal Effects, and Magnetic Recyclability. United States: N. p., 2016. Web. doi:10.1021/acs.jpcc.6b03733.
Larsen, George K., Farr, Will, & Hunyadi Murph, Simona E. Multifunctional Fe 2 O 3 –Au Nanoparticles with Different Shapes: Enhanced Catalysis, Photothermal Effects, and Magnetic Recyclability. United States. doi:10.1021/acs.jpcc.6b03733.
Larsen, George K., Farr, Will, and Hunyadi Murph, Simona E. 2016. "Multifunctional Fe 2 O 3 –Au Nanoparticles with Different Shapes: Enhanced Catalysis, Photothermal Effects, and Magnetic Recyclability". United States. doi:10.1021/acs.jpcc.6b03733. https://www.osti.gov/servlets/purl/1348899.
@article{osti_1348899,
title = {Multifunctional Fe 2 O 3 –Au Nanoparticles with Different Shapes: Enhanced Catalysis, Photothermal Effects, and Magnetic Recyclability},
author = {Larsen, George K. and Farr, Will and Hunyadi Murph, Simona E.},
abstractNote = {},
doi = {10.1021/acs.jpcc.6b03733},
journal = {Journal of Physical Chemistry. C},
number = 28,
volume = 120,
place = {United States},
year = 2016,
month = 7
}
  • In our paper reports a type of multifunctional hybrid nanoparticle (NP) composed of gold nanocrystals coated on and/or embedded in a magnetite-fluorescent porous carbon core-shell NP template (Fe 3O 4@PC-CDs-Au) for biomedical applications, including magnetic/NIR-responsive drug release, multicolor cell imaging, and enhanced photothermal therapy. The synthesis of the Fe 3O 4@PC-CDs-Au NPs firstly involves the preparation of core-shell template NPs with magnetite nanocrystals clustered in the cores and fluorescent carbon dots (CDs) embedded in a porous carbon shell, followed by an in situ reduction of silver ions (Ag +) loaded in the porous carbon shell and a subsequent replacement ofmore » Ag NPs with Au NPs through a galvanic replacement reaction using HAuCl 4 as a precursor. Moreover, the Fe 3O 4@PC-CDsAu NPs can enter the intracellular region and light up mouse melanoma B16F10 cells in multicolor mode. The porous carbon shell, anchored with hydrophilic hydroxyl/carboxyl groups, endows the Fe 3O 4@PC-CDs-Au NPs with excellent stability in the aqueous phase and a high loading capacity (719 mg g -1) for the anti-cancer drug doxorubicin (DOX). The superparamagnetic Fe 3O 4@PC-CDs-Au NPs with a saturation magnetization of 23.26 emu g -1 produce localized heat under an alternating magnetic field, which triggers the release of the loaded drug. The combined photothermal effects of the Au nanocrystals and the CDs on/in the carbon shell can not only regulate the release rate of the loaded drug, but also efficiently kill tumor cells under NIR irradiation. Finally, in benefitting from their excellent optical properties, their magnetic field and NIR light-responsive drug release capabilities and their enhanced photothermal effect, such nanostructured Fe 3O 4@PC-CDs-Au hybrid NPs are very promising for simultaneous imaging diagnostics and high efficacy therapy.« less
  • Carbohydrate binding modules (CBMs) bind polysaccharides and help target glycoside hydrolases catalytic domains to their appropriate carbohydrate substrates. To better understand how CBMs can improve cellulolytic enzyme reactivity, representatives from each of the 18 families of CBM found in Ruminoclostridium thermocellum were fused to the multifunctional GH5 catalytic domain of CelE (Cthe_0797, CelEcc), which can hydrolyze numerous types of polysaccharides including cellulose, mannan, and xylan. Since CelE is a cellulosomal enzyme, none of these fusions to a CBM previously existed. CelEcc_CBM fusions were assayed for their ability to hydrolyze cellulose, lichenan, xylan, and mannan. Several CelEcc_CBM fusions showed enhanced hydrolyticmore » activity with different substrates relative to the fusion to CBM3a from the cellulosome scaffoldin, which has high affinity for binding to crystalline cellulose. Additional binding studies and quantitative catalysis studies using nanostructure-initiator mass spectrometry (NIMS) were carried out with the CBM3a, CBM6, CBM30, and CBM44 fusion enzymes. In general, and consistent with observations of others, enhanced enzyme reactivity was correlated with moderate binding affinity of the CBM. Numerical analysis of reaction time courses showed that CelEcc_CBM44, a combination of a multifunctional enzyme domain with a CBM having broad binding specificity, gave the fastest rates for hydrolysis of both the hexose and pentose fractions of ionic-liquid pretreated switchgrass. In conclusion, we have shown that fusions of different CBMs to a single multifunctional GH5 catalytic domain can increase its rate of reaction with different pure polysaccharides and with pretreated biomass. This fusion approach, incorporating domains with broad specificity for binding and catalysis, provides a new avenue to improve reactivity of simple combinations of enzymes within the complexity of plant biomass.« less
  • Here, carbohydrate binding modules (CBMs) bind polysaccharides and help target glycoside hydrolases catalytic domains to their appropriate carbohydrate substrates. To better understand how CBMs can improve cellulolytic enzyme reactivity, representatives from each of the 18 families of CBM found in Ruminoclostridium thermocellum were fused to the multifunctional GH5 catalytic domain of CelE (Cthe_0797, CelEcc), which can hydrolyze numerous types of polysaccharides including cellulose, mannan, and xylan. Since CelE is a cellulosomal enzyme, none of these fusions to a CBM previously existed.
  • Carbohydrate binding modules (CBMs) bind polysaccharides and help target glycoside hydrolases catalytic domains to their appropriate carbohydrate substrates. To better understand how CBMs can improve cellulolytic enzyme reactivity, representatives from each of the 18 families of CBM found in Ruminoclostridium thermocellum were fused to the multifunctional GH5 catalytic domain of CelE (Cthe-0797, CelEcc), which can hydrolyze numerous types of polysaccharides including cellulose, mannan, and xylan. Since CelE is a cellulosomal enzyme, none of these fusions to a CBM previously existed. Results: CelEcc-CBM fusions were assayed for their ability to hydrolyze cellulose, lichenan, xylan, and mannan. Several CelEcc-CBM fusions showed enhancedmore » hydrolytic activity with different substrates relative to the fusion to CBM3a from the cellulosome scaffoldin, which has high affinity for binding to crystalline cellulose. Additional binding studies and quantitative catalysis studies using nanostructure-initiator mass spectrometry (NIMS) were carried out with the CBM3a, CBM6, CBM30, and CBM44 fusion enzymes. In general, and consistent with observations of others, enhanced enzyme reactivity was correlated with moderate binding affinity of the CBM. Numerical analysis of reaction time courses showed that CelEcc-CBM44, a combination of a multifunctional enzyme domain with a CBM having broad binding specificity, gave the fastest rates for hydrolysis of both the hexose and pentose fractions of ionic-liquid pretreated switchgrass. Conclusion: We have shown that fusions of different CBMs to a single multifunctional GH5 catalytic domain can increase its rate of reaction with different pure polysaccharides and with pretreated biomass. This fusion approach, incorporating domains with broad specificity for binding and catalysis, provides a new avenue to improve reactivity of simple combinations of enzymes within the complexity of plant biomass.« less
  • Abstract not provided.