N-Heterocyclic carbenes as “smart” gold nanoparticle stabilizers: State-of-the art and perspectives for biomedical applications

Thomas, Sophie; Casini, Angela

doi:10.1016/j.jorganchem.2021.121743

Cited by 24 publications

(20 citation statements)

References 99 publications

(128 reference statements)

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“…Two NHC-Au precursor complexes, [bis(1,3-bis(isopropyl)imidazol-2-ylidene)gold(I)]chloride and [bis(1,3-diisopropylbenzimidazolin-2-ylidene)gold(I)](hexafluorophosphate), were synthesized following previously established protocols. 24,25 The resulting 1 H and 13 C NMR spectra matched previous reports 24,25 and display high purity (Figures S1−S6). AuNPs can then be easily functionalized following a benchtop method by Camden, Jenkins, and co-workers, 15 whereby exposing citrate-capped AuNPs to a solution of bis-NHC-Au complex in dichloromethane quickly forms chemisorbed NHC-AuNPs (Figure 3).…”

Section: ■ Results and Discussionsupporting

confidence: 76%

“… 11 NHCs have since become attractive ligands for functionalizing nanoparticle surfaces with applications ranging from catalysis 12 to biomedicine. 13 Due to their strong σ-donation, NHCs readily bind to transition metals resulting in highly robust complexes, 14 which have been used as precursors for appending NHCs to nanoparticles. 15 − 17 Still, for this new class of surface ligands to achieve widespread use in biotechnology, their stability must first be tested in biologically relevant conditions.…”

Section: Introductionmentioning

confidence: 99%

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N-Heterocyclic Carbene Ligand Stability on Gold Nanoparticles in Biological Media

et al. 2021

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The ability to functionalize gold nanoparticle surfaces with target ligands is integral to developing effective nanosystems for biomedical applications, ranging from point-of-care diagnostic devices to site-specific cancer therapies. By forming strong covalent bonds with gold, thiol functionalities can easily link molecules of interest to nanoparticle surfaces. Unfortunately, thiols are inherently prone to oxidative degradation in many biologically relevant conditions, which limits their broader use as surface ligands in commercial assays. Recently, N -heterocyclic carbene (NHC) ligands emerged as a promising alternative to thiols since initial reports demonstrated their remarkable stability against ligand displacement and stronger metal–ligand bonds. This work explores the long-term stability of NHC-functionalized gold nanoparticles suspended in five common biological media: phosphate-buffered saline, tris-glycine potassium buffer, tris-glycine potassium magnesium buffer, cell culture media, and human serum. The NHCs on gold nanoparticles were probed with surface-enhanced Raman spectroscopy (SERS) and X-ray photoelectron spectroscopy (XPS). SERS is useful for monitoring the degradation of surface-bound species because the resulting vibrational modes are highly sensitive to changes in ligand adsorption. Our measurements indicate that imidazole-based NHCs remain stable on gold nanoparticles over the 21 days of examination in all tested environments, with no observed change in the molecule’s SERS signature, XPS response, or UV–vis plasmon band.

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Section: ■ Results and Discussionsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

N-Heterocyclic Carbene Ligand Stability on Gold Nanoparticles in Biological Media

et al. 2021

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“…International Journal of Nanomedicine 2021:16 6070 self-assembly. 68,69 Compared with the Au-S bond, the covalent bond formed by the NHC and Au NPs is stronger, which makes the nanoparticles have better stability in different physiological environments. [70][71][72][73] Many reports have confirmed that NHC-stabilized Au NPs have great potential in biomedicine.…”

Section: Dovepressmentioning

confidence: 99%

“…[70][71][72][73] Many reports have confirmed that NHC-stabilized Au NPs have great potential in biomedicine. 69,73 As a common NHC, under the action of an initiator, polypyrrole (PPy) is used as a protective agent to synthesize a composite urchin-like Au NP of about 6 nm utilizing oxidative polymerization. Compared with bare Au NPs, PPy-coated Au NPs have excellent stability under long-term storage, heat, pH, and laser irradiation and improve light-to-heat conversion efficiency.…”

Section: Dovepressmentioning

confidence: 99%

“…For example, the superb binding ability of NHC to Au NPs has been shown to remain long-term stable in various biological media (pH, GSH, salt solution). 69,71 PEG significantly improves the steric stability of the colloids, allowing the Au NPs to remain well dispersed under different pH and salt ion environments. 185 Similarly, PVP-protected Au NPs exhibited excellent stability in some physiological environments, especially high citrate and citric acid concentrations.…”

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confidence: 99%

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High Stability Au NPs: From Design to Application in Nanomedicine

Zhang¹,

Shao²,

Yue³

et al. 2021

IJN

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In recent years, Au-based nanomaterials are widely used in nanomedicine and biosensors due to their excellent physical and chemical properties. However, these applications require Au NPs to have excellent stability in different environments, such as extreme pH, high temperature, high concentration ions, and various biomatrix. To meet the requirement of multiple applications, many synthetic substances and natural products are used to prepare highly stable Au NPs. Because of this, we aim at offering an update comprehensive summary of preparation high stability Au NPs. In addition, we discuss its application in nanomedicine. The contents of this review are based on a balanced combination of our studies and selected research studies done by worldwide academic groups. First, we address some critical methods for preparing highly stable Au NPs using polymers, including heterocyclic substances, polyethylene glycols, amines, and thiol, then pay attention to natural product progress Au NPs. Then, we sum up the stability of various Au NPs in different stored times, ions solution, pH, temperature, and biomatrix. Finally, the application of Au NPs in nanomedicine, such as drug delivery, bioimaging, photothermal therapy (PTT), clinical diagnosis, nanozyme, and radiotherapy (RT), was addressed concentratedly.

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Gold Complexes in Anticancer Therapy: From New Design Principles to Particle‐Based Delivery Systems

2023

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The discovery of the medicinal properties of gold complexes has fuelled the design and synthesis of new anticancer metallodrugs, which have received special attention due to their unique modes of action. Current research in the development of gold compounds with therapeutic properties is predominantly focused on the molecular design of drug leads with superior pharmacological activities, e.g., by introducing targeting features. Moreover, intensive research aims at improving the physicochemical properties of gold compounds, such as chemical stability and solubility in the physiological environment. In this regard, the encapsulation of gold compounds in nanocarriers or their chemical grafting onto targeted delivery vectors could lead to new nanomedicines that eventually reach clinical applications. Herein, we provide an overview of the state‐of‐the‐art progress of gold anticancer compounds, andmore importantly we thoroughly revise the development of nanoparticle‐based delivery systems for gold chemotherapeutics.

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N-Heterocyclic carbenes as “smart” gold nanoparticle stabilizers: State-of-the art and perspectives for biomedical applications

Cited by 24 publications

References 99 publications

N-Heterocyclic Carbene Ligand Stability on Gold Nanoparticles in Biological Media

N-Heterocyclic Carbene Ligand Stability on Gold Nanoparticles in Biological Media

High Stability Au NPs: From Design to Application in Nanomedicine

Gold Complexes in Anticancer Therapy: From New Design Principles to Particle‐Based Delivery Systems

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