Gold-carbon nanoparticles mediated delivery of BSA: Remarkable robustness and hemocompatibility

Physico-chemical and MR relaxometry study of bovine serum albumin-coated magneto-plasmonic nanoparticles designed for potential use in cancer nanotheranostics

PURPOSE

In recent years, the use of nanoparticles has been developed to improve MRI contrast. To improve the contrast agents in image-guided therapy by Multifunctional nanoparticles, in this study, we synthesized a theranostic magneto-plasmonic nanocomplex based on magnetic iron oxide nanoparticles and bovine serum albumin-modified gold nanorod (Au@BSA-Fe3O4@CMD). The purpose of synthesizing these nanoparticles was to use them as MRI contrast agent and photothermal agents in in vitro and in vivo experiments.

MATERIALS AND METHODS

Initially, the properties of the synthesized nanoparticles were investigated by methods such as DLS, TEM, FTIR. MTT assay was used to evaluate the toxicity of nanoparticles. Finally, to evaluate the contrast ability of nanoparticles, MRI images were taken in in vitro and in vivo conditions and then the images were analyzed.

RESULTS

MTT test results on CT26 cell line showed no significant cytotoxicity for Au@BSA-Fe3O4@CMD nanoparticles at concentrations up to 20 ppm. The in vitro results demonstrated that the Au@BSA-Fe3O4@CMD nanocomplex has high T2 relaxation rate and great relaxivities (r2 = 140.14 mM-1 s-1, r1 = 2.066 mM-1 s-1, r2/r1 = 67.83). For in vivo conditions, a decrease in T2 signal of 9.64 and 11.01, respectively, was observed for intratumoral and intraperitoneal injection of nanoparticles.

CONCLUSION

These in vitro and in vivo studies show that Au @ BSA-Fe3O4@CMD nanoparticles can significantly reduce the signal intensity of T2-weight MRI images, and therefore can offer significant potential as a theranostic platform for effective tumor MR imaging.

Nanoconjugates based on a novel organic-inorganic hybrid silsesquioxane and gold nanoparticles as hemocompatible nanomaterials for promising biosensing applications

A new hybrid organic-inorganic silsesquioxane material, 3-n-propyl(2-amino-4-methyl)pyridium chloride (SiAMPy⁺Cl^-), was synthesized and successfully applied for the synthesis of stable nanoconjugates with gold nanoparticles (AuNPs-SiAMPy⁺). SiAMPy⁺Cl^- was obtained through a simple sol-gel procedure by using chloropropyltrimetoxysilane and tetraethylorthosilicate as precursors and 2-amino-4-methylpyridine as the functionalizing agent. The resulting material was characterized by employing FTIR, XRD, and ¹H-, ¹³C-, and ²⁹Si-NMR spectroscopy. The synthesis of AuNPs-SiAMPy⁺ nanoconjugates was optimized through a 2³ full factorial design. UV-VIS, FTIR, TEM, DLS, and ζ-potential measurements were used to characterize the nanoconjugates, which presented a spherical morphology with an average diameter of 5.8 nm. To investigate the existence of toxic effects of AuNPs-SiAMPy⁺ on blood cells, which is essential for their future biomedical applications, toxicity assays on human erythrocytes and leukocytes were performed. Interestingly, no cytotoxic effects were observed for both types of cells. The nanoconjugates were further applied in the construction of electrochemical immunosensing devices, aiming the detection of anti-Trypanosoma cruzi antibodies in serum as biomarkers of Chagas disease. The AuNPs-SiAMPy⁺ significantly enhanced the sensitivity of the biodevice, which was able to discriminate between anti-T. cruzi positive and negative serum samples. Thus, the AuNPs-SiAMPy⁺-based biosensor showed great potential to be used as a new tool to perform fast and accurate diagnosis of Chagas disease. The promising findings described herein strongly confirm the remarkable potential of SiAMPy⁺Cl^- to obtain nanomaterials, which can present notable biomedical properties and applications.

Recent advances in the protective role of metallic nanoparticles in red blood cells

The interaction of nanoparticles with the biological system has increased with the increasing popularity of nanomedicines. Red blood cells (RBCs) are very sensitive, and abundant cells in the blood. They are highly prone to oxidative damage due to constant interaction with oxygen itself, foreign particles in the blood, and the lack of repair mechanism. The cell membrane of RBCs undergoes lipid peroxidation, protein oxidation, and heme degradation which results in altered membrane permeability, changes in the morphology, and functioning of RBCs. The nanoparticles induce oxidative stress, hemolysis, morphological changes, membrane deformability, and alterations in hemoglobin structure in RBCs. In this review, the effects of metallic nanoparticles and their modifications on the physiology, and life span of RBCs are discussed. The detailed analysis of the antioxidant enzymes-like activity of metal nanoparticles is expected to highlight the beneficial use of these metal nanoparticles in RBCs against oxidative stress and the development of new biosafe nanodrugs.

Rapidly liver-clearable rare-earth core-shell nanoprobe for dual-modal breast cancer imaging in the second near-infrared window

BACKGROUND

Fluorescence imaging as the beacon for optical navigation has wildly developed in preclinical studies due to its prominent advantages, including noninvasiveness and superior temporal resolution. However, the traditional optical methods based on ultraviolet (UV, 200-400 nm) and visible light (Vis, 400-650 nm) limited by their low penetration, signal-to-noise ratio, and high background auto-fluorescence interference. Therefore, the development of near-infrared-II (NIR-II 1000-1700 nm) nanoprobe attracted significant attentions toward in vivo imaging. Regrettably, most of the NIR-II fluorescence probes, especially for inorganic NPs, were hardly excreted from the reticuloendothelial system (RES), yielding the anonymous long-term circulatory safety issue.

RESULTS

Here, we develop a facile strategy for the fabrication of Nd3+-doped rare-earth core-shell nanoparticles (Nd-RENPs), NaGdF4:5%Nd@NaLuF4, with strong emission in the NIR-II window. What's more, the Nd-RENPs could be quickly eliminated from the hepatobiliary pathway, reducing the potential risk with the long-term retention in the RES. Further, the Nd-RENPs are successfully utilized for NIR-II in vivo imaging and magnetic resonance imaging (MRI) contrast agents, enabling the precise detection of breast cancer.

CONCLUSIONS

The rationally designed Nd-RENPs nanoprobes manifest rapid-clearance property revealing the potential application toward the noninvasive preoperative imaging of tumor lesions and real-time intra-operative supervision.

Surface functionalization of nanomaterials by aryl diazonium salts for biomedical sciences

Nanoparticles (NPs) can be prepared by simple reactions and methods from a number of materials. Their small size opens up a number of applications in different fields, among which biomedicine, including: i) drug delivery, ii) biosensors, iii) bioimaging, iv) antibacterial activity. To be able to perform such tasks, NPs must be modified with a variety of functional molecules, such as drugs, targeting groups, chemical tags or antibacterial agents, and must also be prevented from aggregation. The attachment must be stable to resist during the transportation to the targeted location. Diazonium salts, which have been widely used for coupling applications and surface modification, fulfil such criteria. Moreover, they are simple to prepare and can be easily substituted with a large number of organic groups. This review describes the use of these compounds in nanomedicine with a focus on the construction of nanohybrids derived from metal, oxide and carbon-based NPs as well as viruses.

Protein-Coated Aryl Modified Gold Nanoparticles for Cellular Uptake Study by Osteosarcoma Cancer Cells

Gold nanoparticles coated with proteins have shown extraordinary biocompatibility which advanced to several nanomedicine engineering applications. We synthesized protein-coated gold nanoparticles using green and chemical reduction routes for cellular uptake study. In the current work, we coated gold-aryl nanoparticles of the type AuNPs-C₆H₄-4-COOH with bovine serum albumin (BSA), collagen, zein, and lysozyme proteins. Both routes were carried out without phase-transfer catalysts or extraneous stabilizing agents. High crystallinity of the AuNPs synthesized by the green route can be seen in transmission electron microscopy images. Osteosarcoma cancer cells are malignant bone tumors with abnormal cellular functions. Studies using MG-63 cells will provide mechanistic suggestions on the details of the amplification in tumors. We studied the cellular uptake of the bioconjugates by MG-63 osteosarcoma cells using laser confocal fluorescence microscopy (LCFM) and flow cytometry. In the LCFM study, BSA-AuNPs were uptaken most efficiently of all protein-coated gold nanoparticles synthesized by the green route. Lysozyme-AuNPs synthesized by the chemical reduction method were mostly efficiently internalized by MG-63 cells among all AuNPs. Zein- and lysozyme-coated AuNPs, though of relatively small size, prepared by the green method were not efficiently uptaken by MG-63. The two nanoparticles are negatively charged, and zein is also a hydrophobic coat. The difference in hydrophobicity and charge might have affected the internalization. All of those coated nanoparticles that were efficiently uptaken can potentially be used as diagnostic and therapeutic agents for osteosarcoma.

Polyelectrolyte stiffness on gold nanorods mediates cell membrane damage

Charge and surface chemistry of gold nanorods (AuNRs) are often considered the predictive factors for cell membrane damage. Unfortunately, extensive research on AuNR passivated with polyelectrolyte (PE) ligand shell (AuNR-PE) has hitherto left a vital knowledge gap between the mechanical stability of the ligand shell and the cytotoxicity of AuNR-PEs. Here, the agreement between unbiased coarse-grained molecular dynamics (CGMD) simulation and empirical outcomes on hemolysis of red blood cells by AuNR-PEs demonstrates for the first time, a direct impact of the mechanical stability of the PE shell passivating the AuNRs on the lipid membrane rupture. Such mechanical stability is ultimately modulated by the rigidity of the PE components. The CGMD simulation results also reveal the mechanism where the PE chain adsorbs near the surface of the lipid bilayer without penetrating the hydrophobic core of the bilayer, which allows the hydrophobic AuNR core to be in direct contact with the hydrophobic interior of the lipid bilayer, thereby perforating the lipid membrane to induce membrane damage.

Diazonium Gold Salts as Novel Surface Modifiers: What Have We Learned So Far?

The challenges of diazonium salts stabilization have been overcome by their isolation as metal salts such as tetrachloroaurate(III). The cleavage of molecular nitrogen from diazonium salts even at very low potential or on reducing surfaces by fine tuning the substituents on the phenyl ring expanded their applications as surface modifiers in forensic science, nanomedicine engineering, catalysis and energy. The robustness of the metal–carbon bonding produced from diazonium salts reduction has already opened an era for further applications. The integration of experimental and calculations in this field catalyzed its speedy progress. This review provides a narrative of the progress in this chemistry with stress on our recent contribution, identifies potential applications, and highlights the needs in this emerging field. For these reasons, we hope that this review paper serves as motivation for others to enter this developing field of surface modification originating from diazonium salts.

Green and cytocompatible carboxyl modified gold-lysozyme nanoantibacterial for combating multidrug-resistant superbugs

The dissemination of multi-drug resistant (MDR) superbugs in hospital environments, communities and food animals and the very dynamic bacterial mutation frequency require the development of prolonged therapeutic strategies to gain mastery over antibiotic resistance. A AuNP-lysozyme nanoantibacterial was fabricated by the conjugation of AuNPs-C6H4-4-COOH with lysozyme via green reduction of aryldiazonium gold(iii) salt [HOOC-4-C6H4N[triple bond, length as m-dash]N]AuCl4. Results from molecular docking calculations aimed at revealing the binding mode of benzoic acid with the lysozyme structure clearly showed the lowest energy conformation with benzoic acid bound in the deep buried hydrophobic cavity of the protein active site through strong hydrogen bonding and hydrophobic interactions, thus validating the experimental outcomes of the current study which also exhibited the binding of -COOH functional groups in the interior of the protein structure. The superiority of the lysozyme bioconjugate against superbugs was demonstrated by the enhanced and broadened lysozyme antibacterial activities of 98-99% against extended spectrum beta lactamase (ESBL) producing Escherichia coli and imipenem-resistant Pseudomonas aeruginosa clinical isolates and a selection of Gram-negative and Gram-positive standard ATCC strains. Selective toxicity against bacteria was confirmed by the high viability of HeLa and fibroblast cell lines and the outstanding hemocompatibility at the minimum bacterial inhibitory concentrations (MICs). Turbidimetric enzyme kinetic assay showed the enhancement of the lysozyme hydrolytic activity by gold nanoparticles on the Micrococcus lysodeikticus bacterial substrate. Using gel electrophoresis, the induced cell wall breakdown was confirmed by detecting the leaked-out bacterial genomic DNA. The integrity and morphology changes of the E. coli bacteria were investigated using a scanning electron microscope after one hour of contact with the lysozyme-gold bioconjugate. The antibacterial functionalities showed little or no damage to healthy human cells and can be applied to wound dressings and medical devices.

Synthesis of water-soluble gold–aryl nanoparticles with distinct catalytic performance in the reduction of the environmental pollutant 4-nitrophenol

In-depth kinetic insight into the catalytic reduction of nitrophenol pollutant using gold–carbon nanoparticles is described.