Size effect of Au/PAMAM contrast agent on CT imaging of reticuloendothelial system and tumor tissue

Evaluation of PAMAM Dendrimer-Stabilized Gold Nanoparticles: Two-Stage Procedure Synthesis and Toxicity Assessment in MCF-7 Breast Cancer Cells

Gold nanoparticles stabilized with polyamidoamine dendrimers are one of the potential candidates for use as a contrast agent in computed tomography and a drug delivery agent. This work demonstrates a rapid, two-step synthesis of such complexes, which are size-stable for up to 18 months. The first step of the synthesis involves a short sonication of gold (III) chloride hydrate with polyamidoamine dendrimers of the fourth generation, while the second step uses microwaves to reduce gold (III) chloride hydrate with sodium citrate. The developed synthesis method enables rapid production of spherical and monodisperse gold nanoparticles stabilized with polyamidoamine dendrimers. Physicochemical characterization of the gold nanoparticle-polyamidoamine dendrimers complexes was performed using ultraviolet-visible spectroscopy, dynamic light scattering technique, infrared spectroscopy, atomic force microscopy, and transmission electron microscopy. The toxicity of synthesized complexes on the breast cancer MCF-7 cell line has been studied using the tetrazolium salt reduction test. The produced gold nanoparticles revealed lower toxicity levels on the MCF-7 cell line after 18 months from synthesis compared with newly synthesized colloids. Synthesized gold nanoparticles stabilized with dendrimers and commercially available gold nanoparticles stabilized with sodium citrate show similar toxicity levels on breast cancer cells.

Assessment of the influence of gold nanoparticles stabilized with PAMAM dendrimers on HUVEC barrier cells

Civilization diseases, cancer, frequent mutations of viruses and other pathogens constitute the need to look for new drugs, as well as systems for their targeted delivery. One of the promising way of using drugs is supplying them by linking to nanostructures. One of the solution for the development of nanobiomedicine are metallic nanoparticles stabilized with various polymer structures. In this report, we present the synthesis of gold nanoparticles, their stabilization with polyamidoamine (PAMAM) dendrimers with ethylenediamine core and the characteristics of the obtained product (AuNPs/PAMAM). The presence, size and morphology of synthesized gold nanoparticles were evaluated by ultraviolet-visible light spectroscopy, transmission electron microscopy and atomic force microscopy. The hydrodynamic radius distribution of the colloids was analyzed by dynamic light scattering technique. Additionally, the cytotoxicity and changes in mechanical properties of human umbilical vein endothelial cell line (HUVEC) cells caused by AuNPs/PAMAM were assessed. The results of studies on the nanomechanical properties of cells suggest a two-step changes in cell elasticity as a response to contact with nanoparticles. When using AuNPs/PAMAM in lower concentrations, no changes in cell viability were observed and the cells were softer than untreated cells. When higher concentrations were used, a decrease in the cells viability to about 80 % were observed, as well as non-physiological stiffening of the cells. The presented results may play a significant role in the development of nanomedicine.

Nanoscaled PAMAM Dendrimer Spacer Improved the Photothermal-Photodynamic Treatment Efficiency of Photosensitizer-Decorated Confeito-Like Gold Nanoparticles for Cancer Therapy

A critical factor in developing an efficient photosensitizer-gold nanoparticle (PS-AuNP) hybrid system with improved plasmonic photosensitization is to allocate a suitable space between AuNPs and PS. Poly(amidoamine) (PAMAM) dendrimer is selected as a spacer between the PS and confeito-like gold nanoparticles (confeito-AuNPs), providing the required distance (≈2.5-22.5 nm) for plasmon-enhanced singlet oxygen generation and heat production upon 638-nm laser irradiation and increase the cellular internalization of the nanoconjugates. The loading of the PS, tetrakis(4-carboxyphenyl) porphyrin (TCPP) and modified zinc phthalocyanine (ZnPc1) onto PAMAM-confeito-AuNPs demonstrate better in vitro cancer cell-killing efficacy, as the combined photothermal-photodynamic therapies (PTT-PDTs) outperforms the single treatment modalities (PTT or PDT alone). These PS-PAMAM-confeito-AuNPs also demonstrate higher phototoxicity than photosensitizers directly conjugated to confeito-AuNPs (TCPP-confeito-AuNPs and ZnPc1-confeito-AuNPs) against all breast cancer cell lines tested (MDA-MB-231, MCF7 and 4T1). In the in vivo studies, TCPP-PAMAM-confeito-AuNPs are biocompatible and exhibit a selective tumor accumulation effect, resulting in higher antitumor efficacy than free TCPP, PAMAM-confeito-AuNPs and TCPP-confeito-AuNPs. In vitro and in vivo evaluations confirm PAMAM effectiveness in facilitating cellular uptake, plasmon-enhanced singlet oxygen and heat generation. In summary, this study highlights the potential of integrating a PAMAM spacer in enhancing the plasmon effect-based photothermal-photodynamic anticancer treatment efficiency of PS-decorated confeito-AuNPs. This article is protected by copyright. All rights reserved.

Pressure-Controlled Encapsulation of Graphene Quantum Dots into Liposomes by the Reverse-Phase Evaporation Method

Ultrasmall nanoparticles (USNPs) with sizes below 10 nm have shown great potentials in medical applications owing to their outstanding physical, chemical, optical, and biological properties. However, they suffer from a rapid renal clearance and biodegradation rate in the biological environment due to the small size. Liposomes are one of the most promising delivery nanocarriers for loading USNPs because of their excellent biocompatibility and lipid bilayer structure. Encapsulation of USNPs into liposomes in an efficient and controllable manner remains a challenge. In this study, we achieved a high loading of graphene quantum dots (GQDs, ∼4 nm), a typical USNP, into the aqueous core of liposomes (45.68 ± 1.44%), which was controllable by the pressure. The GQDs-loaded liposomes (GQDs-LPs) exhibited a very good aqueous stability for over a month. Furthermore, indocyanine green (ICG), an efficient near-infrared (NIR) photothermal agent, was introduced in the GQDs-LP system that could convert NIR laser energy into thermal energy and break down the liposomes, causing the release of GQDs in 6 min. Moreover, this NIR light-controlled release system (GQDs-ICG-LPs) also exhibited a good photothermal therapeutic performance in vitro, and 75% of cancer cells were killed at a concentration of 200 μg/mL. Overall, the successful development of the NIR light-controlled release system has laid a solid foundation for the future biomedical application of USNPs-loaded liposomes.

Three-dimensional angiography fused with CT/MRI for multimodal imaging of nanoparticles based on Ba4Yb3F17:Lu3+,Gd3+

Designing nanosized multi-modality contrast agents for high-resolution imaging is challenging since most agents are only useful for single-mode imaging. In this work, we successfully synthesized biocompatible polyethylene glycol (PEG-) and l-glutamine (GLN-) modified Ba4Yb3F17:Lu3+,Gd3+ nanoparticles (LNPs@PEG@GLN) that can be employed as a multi-modality contrast agent. Fluorescence dye-modified LNPs@PEG@GLN nanoparticles can be used for computed tomography (CT), magnetic resonance imaging (MRI), and fluorescence imaging (FI). They display high X-ray absorption, outstanding T2-weighted imaging capability, and good fluorescence uptake. Furthermore, LNPs@PEG@GLN enhances contrast efficiencies for different imaging modalities in vivo. Interestingly, LNPs@PEG@GLN is a promising agent for CT angiography. These nanoparticles could be a promising contrast agent for multi-modality imaging and diagnosing vascular diseases.

Contrast-enhanced computed tomography combined with Chitosan-Fe3O4 nanoparticles targeting fibroblast growth factor receptor and vascular endothelial growth factor receptor in the screening of early esophageal cancer

Esophageal cancer is a malignant tumor with a relatively high invasiveness, metastatic potential and worldwide incidence among human cancers. The majority of patients with esophageal cancer are diagnosed in a late tumor stage due to a lack of advanced and sensitive protocols for the diagnosis of patients with early-stage esophageal cancer. In the current study, contrast-enhanced computerized tomography (CECT) combined with Chitosan-Fe₃O₄ nanoparticles targeting fibroblast growth factor receptor (FGFR) and vascular endothelial growth factor receptor (VEGFR; CECT-CNFV) were used to diagnose patients with suspected esophageal cancer. A Chitosan-Fe₃O₄-parceled bispecific antibody targeting FGFR and VEGFR was produced and its affinity to esophageal cancer cells was determined both in vitro and in vivo. A total of 320 patients with suspected esophageal cancer were voluntarily recruited to evaluate the efficacy of CECT-CNFV in the diagnosis of early-stage esophageal cancer. All participants were subjected to CT and CECT-CNFV to detect whether tumors were present in the esophageal area. A Chitosan-Fe₃O₄ nanoparticles contrast agent was orally administered at 20 min prior to CT and CECT-CNFV. The results demonstrated that CECT-CNFV improved diagnostic sensitivity and provided a novel protocol for the diagnosis of tumors in patients with suspected gastric cancer at an early-stage. Furthermore, the resolution ratio of images was enhanced by CECT-CNFV, which enabled the visualization of tiny tumor nodules in esophageal tissue. Clinical data demonstrated that CECT-CNFV diagnosed 200 patients with suspected early-stage esophageal cancer and 120 patients as tumor free. In addition, CECT-CNFV exhibited higher signal enhancement of tumor nodules than CT, suggesting a higher accuracy and accumulation of nanoparticle contrast agent within the tumor nodules of esophageal tissue. Notably, the survival rate of patients with esophageal cancer diagnosed at an early-stage by CECT-CNFV was higher than the mean five-year survival rate (P<0.01). In conclusion, CECT-CNFV enhanced the sensitivity and accuracy of CT in the diagnosis of early-stage esophageal cancer. Thus, CECT-CNFV may improve the accuracy of CT in the diagnosis of mural enhancement in patients with esophageal cancer.

Bakhiet A, Khan A, A. Khan H. Recent Trends in Biomedical Applications of Nanomaterials

In recent years, there have been enormous developments in utilizing the potential of nanotechnology in different fields including biomedical sciences. The most remarkable biomedical applications of nanoparticles (NPs) are in the diagnosis and treatment of various diseases. Functionalization of NPs renders them unique properties so that they can be used as contrast agent for dual or triple modal imaging. The design and synthesis of new generation NPs aiming at targeted drug delivery has revolutionized the safe and effective therapies for complex and difficult to treat diseases. The theranostic NPs possess the dual capabilities for disease diagnosis and treatment. This review highlights the biomedical applications of NPs based on recent reports published in this area of research.

A comparative study of hydrophilic phosphine hexanuclear rhenium cluster complexes' toxicity

The octahedral rhenium cluster compound Na2H8[{Re6Se8}(P(C2H4CONH2)(C2H4COO)2)6] has recently emerged as a very promising X-ray contrast agent for biomedical applications. However, the synthesis of this compound is rather challenging due to the difficulty in controlling the hydrolysis of the initial P(C2H4CN)3 ligand during the reaction process. Therefore, in this report we compare the in vitro and in vivo toxicity of Na2H8[{Re6Se8}(P(C2H4CONH2)(C2H4COO)2)6] with those of related compounds featuring the fully hydrolysed form of the phosphine ligand, namely Na2H14[{Re6Q8}(P(C2H4COO)3)6] (Q = S or Se). Our results demonstrate that the cytotoxicity and acute in vivo toxicity of the complex Na2H8[{Re6Se8}(P(C2H4CONH2)(C2H4COO)2)6] solutions were considerably lower than those of compounds with the fully hydrolysed ligand P(C2H4COOH)3. Such behavior can be explained by the higher osmolality of Na2H14[{Re6Q8}(P(C2H4COO)3)6] versus Na2H8[{Re6Se8}(P(C2H4CONH2)(C2H4COO)2)6].

Highly water-stable rare ternary Ag-Au-Se nanocomposites as long blood circulation time X-ray computed tomography contrast agents

X-ray computed tomography (CT) is a powerful and widely used medical non-invasive technique that often requires intravenous administration of contrast agents (CAs) to better visualize soft tissues. In this work, we have developed a novel CT contrast agent based on ternary Ag-Au-Se chalcogenide nanoparticles (NP). A facile ligand exchange by using a 3 kDa PEGylated ligand with a dithiol dihydrolipoic acid as an anchor group resulted in highly water-soluble and monodisperse nanoparticles. These PEGylated ternary NPs were tested in vivo in mice, showing slow uptake by the mononuclear phagocyte system, long blood circulation times, low toxicity, and very good X-ray contrast, thus being promising candidates as CT contrast agents for clinical applications.