Preparation of carboxyl group-modified palladium nanoparticles in an aqueous solution and their conjugation with DNA

Wang, Zhifei; Li, Hongying; Zhen, Shuang; He, Nongyue

doi:10.1039/c2nr30649b

Cited by 14 publications

(14 citation statements)

References 24 publications

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“…At least, however, the amount of discarded thiol DNA is expected to be minimized. Importantly, the novel method presented in this work for enhancing the DNA loading on AuNPs would offer substantial convenience and cost‐effectiveness to researchers who develop the synthesis and applications of DNA conjugates of other nanoparticles, including silver, palladium, platinum, and silica …”

Section: Methodsmentioning

confidence: 99%

Controlling Chemical Equilibrium for Efficient Nanoparticle Conjugation and Release of DNA

Joo

Kim

Lee

2015

Bulletin Korean Chem Soc

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The highly enhanced binding properties of deoxyribonucleic acid (DNA)-gold nanoparticle conjugates (DNA-AuNPs) have attracted researchers' attention because they could be the fundamental origin of the high sensitivity of detection schemes employing the DNA-AuNPs as functional nanoprobes.1 -3 The binding constant of the DNA-AuNPs was determined to be of two orders of magnitude as high as that of free single stranded DNA, which was not the case with sparsely conjugated DNA strands on nanoparticles.4,5 In a typical conjugation procedure, citrate-coated AuNPs are combined with excess thiol DNA, which essentially leads to the limited DNA loading per AuNP and the discard of unconjugated costly thiol DNA (approximately 95%, assuming 100 DNA strands per AuNP).1 To date, several chemical and physical methods have been developed to effectively increase the DNA density on AuNPs. For example, DNAAuNP conjugation reaction was conducted at high NaCl concentrations, 6 with sonication, 6 or under acidic (pH 3) conditions 7 to increase the density of DNA on AuNPs. While effective and convenient, however, these methods are hampered by the necessity of additional chemicals or instrumentation.In contrast to the DNA-conjugation reaction, the detailed chemical conditions where the DNA strands are released from the nanoparticle surface have been less frequently investigated. In fact, the complete release of DNA from nanoparticles is as important as the DNA-nanoparticle conjugation, because it is directly associated with the accurate evaluation of DNA loading, a measure of the DNA conjugation efficiency. Conventionally, organic alkylthiol molecules in excess were employed to displace the monothiol DNA, but they were hampered by the poor water solubility and environmental harm.8 Instead of the displacing chemicals, potassium cyanide (KCN) was used to dissolve the gold nanoparticles, whose toxicity, however, could be an even larger concern than that of alkylthiols.9,10 Recently, sodium borohydride (NaBH 4 ) was used to release organic thiol molecules from AuNPs, potentially applicable to the DNA release.11 Currently, dithiothreitol (DTT) is the most widely used displacing reagent for thiol DNA on AuNPs because of its high water solubility, low toxicity, and facile removal after the displacement. 12 The detailed displacement conditions, however, are not fully investigated yet, and are required to be further improved for efficient and optimized quantification of DNA strands conjugated with AuNPs.Herein, we present a facile and cost-effective method for maximizing DNA loading on AuNPs simply by increasing the AuNP concentration and thus shifting chemical equilibrium of the DNA-AuNP conjugation reaction (Scheme 1(a)). Importantly, this method is extremely simple, straightforward, and can be applied to any DNA sequences. Moreover, it does not require any additional instrumentation or chemical reagents. For the accurate measurement of DNA loading, we first systematically investigated the DTT displacement of DNA strands on AuNPs at various tempe...

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Section: Methodsmentioning

confidence: 99%

Controlling Chemical Equilibrium for Efficient Nanoparticle Conjugation and Release of DNA

Joo

Kim

Lee

2015

Bulletin Korean Chem Soc

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“…[28][29][30]41 Most of these studies were oriented toward catalytic applications [42][43][44] and sensor devices. 45,46 The direct reduction route that was developed in this study makes use of biocompatible molecules (AA DMSA), enabling the synthesis of Pd and Pd@Au NPs. AA was used as the reducing agent, and DMSA as the stabilising agent, respectively.…”

Section: Resultsmentioning

confidence: 99%

Rapid, one-pot procedure to synthesise¹⁰³Pd:Pd@Au nanoparticles en route for radiosensitisation and radiotherapeutic applications

et al. 2015

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ARTICLEThis journal is © The Royal Society of Chemistry 2013 J. Name., 2013, 00, 1--3 | 1 The radioisotope palladium ( 103 Pd), encapsulated in millimetre-size seed implants, is widely used in prostate cancer brachytherapy. Gold nanoparticles (Au NPs) distributed in the vicinity of 103 Pd radioactive implants, strongly enhance the therapeutic dose of radioactive implants (radiosensitisation effect). A new strategy under development to replace millimetre-size implants, consist in injecting radioactive NPs in the affected tissues. The development of 103 Pd@Au NPs distributed in the diseased tissue, could increase the uniformity of treatment (compared with massive seeds), while enhancing the radiotherapeutic dose to the cancer cells (through Au-mediated radiosensitisation effect). To achieve this goal, it is necessary to develop a rapid, efficient, one-pot and easy-to-automatise procedure, allowing the synthesis of coreshell Pd@Au NPs. The novel synthesis route proposed here enables the production of Pd@Au NPs in not more than 4h, in aqueous media, with minimal manipulations, and relying on biocompatible and non-toxic molecules. This rapid multi-step process consists of the preparation of ultra-small Pd NPs by chemical reduction of an aqueous solution of H 2 PdCl 4 supplemented with ascorbic acid (AA) as reducing agent and 2, 3-meso-dimercaptosuccinic acid (DMSA) as a capping agent. Pd conversion yields close to 87% were found, indicating the efficiency of the reaction process. Then Pd NPs were used as seeds for the growth of a gold shell (Pd@Au), followed by grafting with polyethylene glycol (PEG) to ensure colloidal stability. Pd@Au-PEG (TEM: 20.2 ± 12.1 nm) formed very stable colloids in saline solution as well as in cell culture medium. The physico-chemical properties of the particles were characterised by FTIR, XPS, and UV-vis. spectroscopies. The viability of PC3 human prostate cancer cells was not affected after a 24-h incubation cycle with Pd@Au-PEG NPs to concentrations up to 4.22 mM Au. Finally, suspensions of Pd@Au-PEG NPs measured in computed tomography (CT) are found to attenuate X-rays more efficiently than commercial Au NPs CT contrast media. A proof-of-concept was performed to demonstrate the possibility synthesise radioactive 103 Pd:Pd@Au-PEG NPs. This study reveals the possibility to synthesise Pd@Au NPs rapidly (including radioactive 103 Pd:Pd@Au-PEG NPs), and following a methodology that respects all the strict requirements underlying the production of NPs for radiotherapeutic use (rapidity, reaction yield, colloidal stability, NPs concentration, purification). Journal of Materials Chemistry B RSCPublishing ARTICLEThis journal is

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“…Those eight dyes were alizarin, calconcarboxylic acid, cresol red, crystal violet, fluorescein, methylthymol blue, phenol red, and xylenol orange. Amino-functionalized polystyrene microbeads with a 100–120-µm diameter were used as substrates to conjugate the selected dyes by using EDC (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide) cross-linker [ 34 , 35 ]. Microbeads (100 mg) were washed twice in 10 mL of pH 7.4 PBS (phosphate buffered saline).…”

Section: Methodsmentioning

confidence: 99%

Colorimetric Sensor Array for White Wine Tasting

Chung

Park

et al. 2015

Sensors

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A colorimetric sensor array was developed to characterize and quantify the taste of white wines. A charge-coupled device (CCD) camera captured images of the sensor array from 23 different white wine samples, and the change in the R, G, B color components from the control were analyzed by principal component analysis. Additionally, high performance liquid chromatography (HPLC) was used to analyze the chemical components of each wine sample responsible for its taste. A two-dimensional score plot was created with 23 data points. It revealed clusters created from the same type of grape, and trends of sweetness, sourness, and astringency were mapped. An artificial neural network model was developed to predict the degree of sweetness, sourness, and astringency of the white wines. The coefficients of determination (R2) for the HPLC results and the sweetness, sourness, and astringency were 0.96, 0.95, and 0.83, respectively. This research could provide a simple and low-cost but sensitive taste prediction system, and, by helping consumer selection, will be able to have a positive effect on the wine industry.

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Preparation of carboxyl group-modified palladium nanoparticles in an aqueous solution and their conjugation with DNA

Cited by 14 publications

References 24 publications

Controlling Chemical Equilibrium for Efficient Nanoparticle Conjugation and Release of DNA

Controlling Chemical Equilibrium for Efficient Nanoparticle Conjugation and Release of DNA

Rapid, one-pot procedure to synthesise¹⁰³Pd:Pd@Au nanoparticles en route for radiosensitisation and radiotherapeutic applications

Colorimetric Sensor Array for White Wine Tasting

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Preparation of carboxyl group-modified palladium nanoparticles in an aqueous solution and their conjugation with DNA

Cited by 14 publications

References 24 publications

Controlling Chemical Equilibrium for Efficient Nanoparticle Conjugation and Release of DNA

Controlling Chemical Equilibrium for Efficient Nanoparticle Conjugation and Release of DNA

Rapid, one-pot procedure to synthesise103Pd:Pd@Au nanoparticles en route for radiosensitisation and radiotherapeutic applications

Colorimetric Sensor Array for White Wine Tasting

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Product

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Rapid, one-pot procedure to synthesise¹⁰³Pd:Pd@Au nanoparticles en route for radiosensitisation and radiotherapeutic applications