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Niedner L, Kickelbick G. Amphiphilic titania Janus nanoparticles containing ionic groups prepared in oil-water Pickering emulsion. NANOSCALE 2024; 16:7396-7408. [PMID: 38445431 DOI: 10.1039/d3nr04907h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Titania nanoparticles with a diameter of 8 nm underwent an anisotropic modification using apolar 6-bromohexylphosphonic acid and cationic polar N,N,N-trimethyl-6-phosphonohexan-1-aminium bromide. The Janus modification was achieved through a straightforward one-step Pickering emulsion approach using toluene-water mixtures. The resulting Janus particles were compared with isotropically and statistically modified titania particles, where either a single coupling agent is attached to the surface or both coupling agents are assembled over the surface randomly, respectively. The covalent binding of the phosphonic acids to the titania surface was confirmed by FTIR and 31P solid-state CP-MAS NMR analyses. The grafting density was assessed using TGA, elemental analysis, and ICP-MS, revealing grafting densities of 0.1 mmol g-1 to 0.5 mmol g-1 for the cationic coupling agent and 1.2 mmol g-1 to 1.5 mmol g-1 for the apolar coupling agent, respectively. ζ-Potential titration measurements of both pristine and modified particles revealed isoelectric points at pH 4.5 to 9.3, depending on the type of modification. The ability of the particles to stabilize Pickering emulsions was tested under various conditions, with statistically and Janus-modified particles demonstrating a significant increase in stabilization compared to their isotropically modified counterparts. Furthermore, Janus particles were deposited onto glass substrates by a simple layer-by-layer approach. Through the self-assembly of these Janus particles, the glass substrate's properties could be tailored from hydrophilic to hydrophobic to hydrophilic, depending on the dipping cycle.
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Affiliation(s)
- Lucas Niedner
- Saarland University, Inorganic Solid State Chemistry, Campus, Building C4 1, 66123 Saarbrücken, Germany.
| | - Guido Kickelbick
- Saarland University, Inorganic Solid State Chemistry, Campus, Building C4 1, 66123 Saarbrücken, Germany.
- Saarene - Saarland Center for Energy Materials and Sustainability, Campus C4 2, 66123 Saarbrücken, Germany
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Karthäuser S, Peter S, Simon U. Integration of Individual Functionalized Gold Nanoparticles into Nanoelectrode Configurations: Recent Advances. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Silvia Karthäuser
- Peter Grünberg Institut (PGI‐7) and JARA‐FIT Forschungszentrum Jülich GmbH 52425 Jülich Germany
| | - Sophia Peter
- Institute of Inorganic Chemistry and JARA‐FIT RWTH Aachen University 52074 Aachen Germany
| | - Ulrich Simon
- Institute of Inorganic Chemistry and JARA‐FIT RWTH Aachen University 52074 Aachen Germany
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Slabu I, Wiemer K, Steitz J, Liffmann R, Mues B, Eisold S, Caumanns T, Mayer J, Kuhl CK, Schmitz-Rode T, Simon U. Size-Tailored Biocompatible FePt Nanoparticles for Dual T1/ T2 Magnetic Resonance Imaging Contrast Enhancement. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10424-10434. [PMID: 31306025 DOI: 10.1021/acs.langmuir.9b00337] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The development of new contrast agents (CAs) for magnetic resonance imaging (MRI) is of high interest, especially because of the increased concerns of patient safety and quick clearance of clinically used gadolinium and iron oxide-based CAs, respectively. Here, a two-step synthesis of superparamagnetic water-soluble iron platinum (FePt) nanoparticles (NPs) with core sizes between 2 and 8 nm for use as CAs in MRI is reported. First, wet-chemical organometallic NPs are synthesized by thermal decomposition in the presence of stabilizing oleic acid and oleylamine. Second, the hydrophobic NPs are coated with an amphiphilic polymer and transferred into aqueous media. Their magnetization values and relaxation rates exceed those published for CAs already used for clinical application. Their saturation magnetization increases with the core size to approximately 82 A·m2/kgFe. For 8 nm NPs, the T2 relaxivity of approximately 221 (mM·s)-1 is 5 times larger than that for the ferumoxides, and for 6 nm NPs, the T1 relaxivity of approximately 12 (mM·s)-1 is slightly higher than that of ultrasmall gadolinium oxide NPs. The 6 nm FePt NPs are identified as excellent CAs for both T1 and T2 imaging. Most importantly, because of their coating, significantly low cytotoxicity is achieved. FePt NPs prove to be a promising alternative to gadolinium and iron oxide NPs showing high-quality CA characteristics for both T1- and T2-weighted images.
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Affiliation(s)
| | - Katharina Wiemer
- Institute of Inorganic Chemistry , RWTH Aachen University , Aachen 52056 , Germany
| | | | - Rebecca Liffmann
- Institute of Inorganic Chemistry , RWTH Aachen University , Aachen 52056 , Germany
| | | | - Sabine Eisold
- Institute of Inorganic Chemistry , RWTH Aachen University , Aachen 52056 , Germany
| | | | | | | | | | - Ulrich Simon
- Institute of Inorganic Chemistry , RWTH Aachen University , Aachen 52056 , Germany
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Wang K, Li F, Tian D, Xu J, Liu Y, Hou Z, Zhou H, Chen S, Zhu J, Yang Z. Segmental Janus nanoparticles of polymer composites. Chem Commun (Camb) 2019; 55:8114-8117. [DOI: 10.1039/c9cc03067k] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We demonstrate a facile yet robust “plasma etching and grafting” strategy to prepare Janus nanoparticles coated with binary polymer brushes on two different sides. The ratio of two types of polymers can be tailored by tuning the plasma etching power.
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Kaulen C, Simon U. Ion specific effects on the immobilisation of charged gold nanoparticles on metal surfaces. RSC Adv 2018; 8:1717-1724. [PMID: 35540875 PMCID: PMC9077124 DOI: 10.1039/c7ra10374c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/19/2017] [Indexed: 12/25/2022] Open
Abstract
Since the pioneering work of F. Hofmeister, Arch. Exp. Pathol. Pharmakol., 1888, 24, 247, ion specific effects have been steadily reported in the context of colloidal or protein stabilisation in electrolyte solutions. Although the observed effects are omnipresent in chemistry and biology, their origin is still under ferocious discussion. Here, we report on ion specific effects affecting the self-assembly of amine and carboxylic acid functionalised gold nanoparticles on metal surfaces as well as in electrolyte solution as a function of the monovalent cations Li+, Na+, K+ and Cs+. Mercaptooctanoic acid and 1,8-amine-octanethiol functionalised gold nanoparticles were adsorbed on structured AuPd/Pt substrates under addition of the respective chloride salts. Furthermore, the influence of the same salts on the salt induced aggregation of these AuNP was investigated. Our results demonstrate that the assembly processes on the metal surface as well as in electrolyte solution are influenced by the addition of different cations. We attribute the observed effects to ion pairing of the functional end groups with the added cations. With these findings we introduce a new parameter to control the self-assembly of 2D AuNP arrays on solid supports or of 3D AuNP networks in solution, which could be of relevance for the fabrication of new tailor-made functional materials or for biomedical applications.
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Affiliation(s)
- C Kaulen
- JARA - FIT, RWTH Aachen University 52074 Aachen Germany
- Institute of Inorganic Chemistry, RWTH Aachen University 52074 Aachen Germany
| | - U Simon
- JARA - FIT, RWTH Aachen University 52074 Aachen Germany
- Institute of Inorganic Chemistry, RWTH Aachen University 52074 Aachen Germany
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Nguyen VH, Kaulen C, Simon U, Schnakenberg U. Single Interdigital Transducer Approach for Gravimetrical SAW Sensor Applications in Liquid Environments. SENSORS 2017; 17:s17122931. [PMID: 29258213 PMCID: PMC5751692 DOI: 10.3390/s17122931] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/09/2017] [Accepted: 12/12/2017] [Indexed: 12/05/2022]
Abstract
Surface acoustic wave (SAW) devices are well known for mass-sensitive sensor applications. In biosensing applications, chemical and biochemically evoked binding processes on surfaces are detected in liquid environments using delay line or resonator sensor configurations, preferably in combination with the appropriate microfluidic devices. All configurations share the common feature of analyzing the transmission characteristic of the propagating SAW. In this paper, a novel SAW-based impedance sensor type is introduced which uses only one interdigital transducer (IDT), simultaneously as the SAW generator and the sensor element. Here, the input port reflection coefficient S11 is measured at the IDT instead of the commonly used S21 transmission forward gain parameter. Thus, a sharp and distinct peak of the S11 spectrum is obtained, enabling a comfortable direct readout of the sensor signal. Proof of the concept was gained by analyzing the specific binding of the 4-mercaptophenylacetic acid gold nanoparticles (MPA–AuNP) directly to the IDT surface. The corresponding binding kinetic of the MPA–AuNP on the functionalized gold surface has been analyzed and a sensitivity of 7.4 mΩ nM−1 has been determined.
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Affiliation(s)
- Vu Hoa Nguyen
- Institute of Materials in Electrical Engineering 1, RWTH Aachen University, 52074 Aachen, Germany.
| | - Corinna Kaulen
- Institute of Inorganic Chemistry and JARA-Fundamentals of Future Information Technologies, RWTH Aachen University, 52074 Aachen, Germany.
| | - Ulrich Simon
- Institute of Inorganic Chemistry and JARA-Fundamentals of Future Information Technologies, RWTH Aachen University, 52074 Aachen, Germany.
| | - Uwe Schnakenberg
- Institute of Materials in Electrical Engineering 1, RWTH Aachen University, 52074 Aachen, Germany.
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Gold nanoparticles with patterned surface monolayers for nanomedicine: current perspectives. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:749-771. [PMID: 28865004 PMCID: PMC5693983 DOI: 10.1007/s00249-017-1250-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/20/2017] [Accepted: 08/22/2017] [Indexed: 10/27/2022]
Abstract
Molecular self-assembly is a topic attracting intense scientific interest. Various strategies have been developed for construction of molecular aggregates with rationally designed properties, geometries, and dimensions that promise to provide solutions to both theoretical and practical problems in areas such as drug delivery, medical diagnostics, and biosensors, to name but a few. In this respect, gold nanoparticles covered with self-assembled monolayers presenting nanoscale surface patterns-typically patched, striped or Janus-like domains-represent an emerging field. These systems are particularly intriguing for use in bio-nanotechnology applications, as presence of such monolayers with three-dimensional (3D) morphology provides nanoparticles with surface-dependent properties that, in turn, affect their biological behavior. Comprehensive understanding of the physicochemical interactions occurring at the interface between these versatile nanomaterials and biological systems is therefore crucial to fully exploit their potential. This review aims to explore the current state of development of such patterned, self-assembled monolayer-protected gold nanoparticles, through step-by-step analysis of their conceptual design, synthetic procedures, predicted and determined surface characteristics, interactions with and performance in biological environments, and experimental and computational methods currently employed for their investigation.
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Zhang Y, Miao L, Wang HF. Fluorescence Anisotropy as a Reliable Discrimination of Ligand-Asymmetric and Symmetric Mn-Doped ZnS Quantum Dots. Anal Chem 2016; 88:9714-9719. [DOI: 10.1021/acs.analchem.6b02614] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu Zhang
- Research Center for Analytical
Sciences, College of Chemistry, Key
Laboratory of Biosensing, Molecular Recognition, State Key Laboratory
of Medicinal Chemical Biology and ‡Collaborative Innovation Center of Chemical
Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Lin Miao
- Research Center for Analytical
Sciences, College of Chemistry, Key
Laboratory of Biosensing, Molecular Recognition, State Key Laboratory
of Medicinal Chemical Biology and ‡Collaborative Innovation Center of Chemical
Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - He-Fang Wang
- Research Center for Analytical
Sciences, College of Chemistry, Key
Laboratory of Biosensing, Molecular Recognition, State Key Laboratory
of Medicinal Chemical Biology and ‡Collaborative Innovation Center of Chemical
Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
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