Safety of Gold Nanoparticles: From In Vitro to In Vivo Testing Array Checklist

Ultrasound-Driven Deposition of Au and Ag Nanoparticles on Citrus Pectin: Preparation and Characterisation of Antimicrobial Composites

Pectin is a renewable, non-toxic and biodegradable polymer made of galacturonic acid units. Its polar groups make it suitable for complexing and supporting metallic nanoparticles (NPs). This work aimed to produce antibacterial nanocomposites using pectin and acoustic cavitation. The metal NPs (Au or Ag) were deposited using ultrasound (US, 21 kHz, 50 W) and compared with those achieved with mechanical stirring. The impact of the reducing agents (NaBH4, ascorbic acid) on the dispersion and morphology of the resulting NPs was also assessed. Characterization by diffuse reflectance (DR) UV-Vis-NIR spectroscopy and field emission scanning electron microscopy (FESEM) showed that the use of US improves the dispersion and decreases the size of both Au and Ag NPs. Moreover, with Au NPs, avoiding external reductants led to smaller NPs and more uniform in size. The prepared NPs were functionalized with oxytetracycline in water and tested against Escherichia coli (gram negative) and Staphylococcus epidermidis (gram positive) via the Kirby-Bauer test. The results show a better antibacterial activity of the functionalized nanoparticles compared to antibiotic-free NPs and pure oxytetracycline, advising the potential of the nanoparticles as drug carriers. These findings underscore the significance of US-assisted synthesis, paving the way to new environmentally friendly antimicrobial materials.

A review on toxicity mechanism and risk factors of nanoparticles in respiratory tract

This comprehensive review focuses on various dimensions of nanoparticle toxicity, emphasizing toxicological characteristics, assessment techniques, and examinations of relevant studies on the effects on biological systems. The primary objective is to comprehend the potential risks associated with nanoparticles and to provide efficient strategies for mitigating them by consolidating current research discoveries. For in-depth insights, the discussions extend to crucial aspects such as toxicity associated with different nanoparticles, human exposure, and nanoparticle deposition in the human respiratory tract. The analysis utilizes the multiple-path particle dosimetry (MPPD) modeling for computational simulation. The SiO2 nanoparticles with a volume concentration of 1% and a particle size of 50 nm are used to depict the MPPD modeling of the Left upper (LU), left lower (LL), right upper (RU), right middle (RM), and right lower (RL) lobes in the respiratory tract. The analysis revealed a substantial 67.5% decrease in the deposition fraction as the particle size increased from 10 nm to 100 nm. Graphical representation emphasizes the significant impact of exposure path selection on nanoparticle deposition, with distinct deposition values observed for nasal, oral, oronasal-mouth breather, oronasal - normal augmenter, and endotracheal paths (0.00291 μg, 0.00332 μg, 0.00297 μg, 0.00291 μg, and 0.00383 μg, respectively). Consistent with the focus of the review, the article also addresses crucial mitigation strategies for managing nanoparticle toxicity.

A Step Forward for the Treatment of Localized Prostate Cancer Using Gold Nanoparticles Combined with Laser Irradiation

Prostate cancer (PCA) is the second most common cancer diagnosis in men and the fifth leading cause of death worldwide. The conventional treatments available are beneficial to only a few patients and, in those, some present adverse side effects that eventually affect the quality of life of most patients. Thus, there is an urgent need for effective, less invasive and targeted specific treatments for PCA. Photothermal therapy (PTT) is a minimally invasive therapy that provides a localized effect for tumour cell ablation by activating photothermal agents (PTA) that mediate the conversion of the light beam's energy into heat at the site. As tumours are unable to easily dissipate heat, they become more susceptible to temperature increases. In the PTT field, gold nanoparticles (AuNPs) have been attracting interest as PTA. The aim of this study was to formulate AuNPs capable of remaining retained in the tumour and subsequently generating heat at the tumour site. AuNPs were synthesized and characterized in terms of size, polydispersity index (PdI), zeta potential (ZP), morphology and the surface plasmon resonance (SPR). The safety of AuNPs and their efficacy were assessed using in vitro models. A preliminary in vivo safety assessment of AuNPs with a mean size lower than 200 nm was confirmed. The morphology was spherical-like and the SPR band showed good absorbance at the laser wavelength. Without laser, AuNPs proved to be safe both in vitro (>70% viability) and in vivo. In addition, with laser irradiation, they proved to be relatively effective in PCA cells. Overall, the formulation appears to be promising for use in PTT.

Radioactive gold nanoparticles coated with BSA: A promising approach for prostate cancer treatment

Background: Nanotechnology has revolutionized medicine, especially in oncological treatments. Gold nanoparticles (AuNPs) stand out as an innovative alternative due to their biocompatibility, potential for surface modification, and effectiveness in radiotherapeutic techniques. Given that prostate cancer ranks as one of the leading malignancies among men, there's a pressing need to investigate new therapeutic approaches. Methods: AuNPs coated with bovine serum albumin (BSA) were synthesized and their cytotoxicity was assessed against prostate tumor cell lines (LNCaP and PC-3), healthy prostate cells (RWPE-1), and endothelial control cells (HUVEC) using the MTS/PMS assay. For in vivo studies, BALB/C Nude mice were employed to gauge the therapeutic efficacy, biodistribution, and hematological implications post-treatment with BSA-coated AuNPs. Results: The BSA-coated AuNPs exhibited cytotoxic potential against PC-3 and LNCaP lines, while interactions with RWPE-1 and HUVEC remain subjects for further scrutiny. Within animal models, a diverse therapeutic response was observed, with certain instances indicating complete tumor regression. Biodistribution data emphasized the nanoparticles' affinity towards particular organs, and the majority of hematological indicators aligned with normative standards. Conclusions: BSA-coated AuNPs manifest substantial promise as therapeutic tools in treating prostate cancer. The present research not only accentuates the nanoparticles' efficacy but also stresses the imperative of optimization to ascertain both selectivity and safety. Such findings illuminate a promising trajectory for avant-garde therapeutic modalities, holding substantial implications for public health advancements.

Hybrid Nanoparticle-Assisted Chemo-Photothermal Therapy and Photoacoustic Imaging in a Three-Dimensional Breast Cancer Cell Model

Bioinspired nanoparticles have recently been gaining attention as promising multifunctional nanoplatforms for therapeutic applications in cancer, including breast cancer. Here, the efficiency of the chemo-photothermal and photoacoustic properties of hybrid albumin-modified nanoparticles (HSA-NPs) loaded with doxorubicin was evaluated in a three-dimensional breast cancer cell model. The HSA-NPs showed a higher uptake and deeper penetration into breast cancer spheroids than healthy breast cell 3D cultures. Confocal microscopy revealed that, in tumour spheroids incubated with doxorubicin-loaded NPs for 16 h, doxorubicin was mainly localised in the cytoplasm, while a strong signal was detectable at the nuclear level after 24 h, suggesting a time-dependent uptake. To evaluate the cytotoxicity of doxorubicin-loaded NPs, tumour spheroids were treated for up to 96 h with increasing concentrations of NPs, showing marked toxicity only at the highest concentration of doxorubicin. When doxorubicin administration was combined with laser photothermal irradiation, enhanced cytotoxicity was observed at lower concentrations and incubation times. Finally, the photoacoustic properties of doxorubicin-loaded NPs were evaluated in tumour spheroids, showing a detectable signal increasing with NP concentration. Overall, our data show that the combined effect of chemo-photothermal therapy results in a shorter exposure time to doxorubicin and a lower drug dose. Furthermore, owing to the photoacoustic properties of the NPs, this nanoplatform may represent a good candidate for theranostic applications.

Targeted Glioblastoma Treatment via Synthesis and Functionalization of Gold Nanoparticles With De Novo-Engineered Transferrin-Like Peptides: Protocol for a Novel Method

BACKGROUND

Glioblastoma multiforme (GBM) is an aggressive brain tumor with limited treatment options due to the blood-brain barrier's (BBB's) impedance and inherent resistance to chemotherapy. Gold nanoparticles (AuNPs) functionalized with transferrin-like peptides show promise in overcoming these challenges, enhancing drug delivery to the brain, and reducing chemotherapy resistance.

OBJECTIVE

The primary goal of this study is to establish a detailed protocol for synthesizing and stabilizing AuNPs, functionalizing them with de novo-engineered transferrin-like peptides, and conjugating them with the chemotherapeutic agent temozolomide. This strategy aims to improve drug delivery across the BBB and circumvent chemotherapy resistance. The secondary objective includes an assessment of the safety and potential for in vivo use of the synthesized nanoparticle complex.

METHODS

The proposal involves multiple steps with rigorous quality control of AuNP synthesis, stabilization with surfactants, and polyethylene glycol coating. The engineered transferrin-like peptides will be synthesized and attached to the AuNPs' surface, followed by the attachment of temozolomide and O6-methylguanine-DNA methyltransferase inhibitors. The resulting complex will undergo in vitro testing to assess BBB penetration, efficacy against GBM cells, and potential toxicity.

RESULTS

Initial preliminary experiments and simulations suggest successful synthesis and stabilization of AuNPs and effective attachment of transferrin-like peptides. We propose peptide attachment verification using Fourier transform infrared spectroscopy and surface plasmon resonance. Additionally, we will conduct pH stability tests to ensure our functionalized AuNPs retain their properties in acidic brain tumor microenvironments.

CONCLUSIONS

The proposed functionalization of AuNPs with de novo-engineered transferrin-like peptides represents a novel approach to GBM treatment. Our strategy opens new avenues for drug delivery across the BBB and chemotherapy resistance reduction. While we primarily focus on in vitro studies and computational modeling at this stage, successful completion will lead to further development, including in vivo studies and nanoparticle design optimization. This proposal anticipates inspiring future research and funding in neuro-oncology, presenting a potentially innovative and effective treatment option for GBM.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/49417.