Green One-Step Synthesis of Medical Nanoagents for Advanced Radiation Therapy

Human Serum Albumin in the Presence of Small Platinum Nanoparticles

Noble metal materials, especially platinum nanoparticles (Pt NPs), have immense potential in nanomedicine as therapeutic agents on account of their high electron density and their high surface area. Intravenous injection is proposed as the best mode to deliver the product to patients. However, our understanding of the reaction of nanoparticles with blood components, especially proteins, is far behind the explosive development of these agents. Using synchrotron radiation circular dichroism (SRCD), we investigated the structural and stability changes of human serum albumin (HSA) upon interaction with PEG-OH coated Pt NPs at nanomolar concentrations, conditions potentially encountered for intravenous injection. There is no strong complexation found between HSA and Pt NPs. However, for the highest molar ratio of NP:HSA of 1:1, an increase of 18 °C in the thermal unfolding of HSA was observed, which is attributed to increased thermal stability of HSA generated by preferential hydration. This work proposes a new and fast method to probe the potential toxicity of nanoparticles intended for clinical use with intravenous injection.

Prospects of nanoparticle-based radioenhancement for radiotherapy

Radiotherapy is a key pillar of solid cancer treatment. Despite a high level of conformal dose deposition, radiotherapy is limited due to co-irradiation of organs at risk and subsequent normal tissue toxicities. Nanotechnology offers an attractive opportunity for increasing the efficacy and safety of cancer radiotherapy. Leveraging the freedom of design and the growing synthetic capabilities of the nanomaterial-community, a variety of engineered nanomaterials have been designed and investigated as radiosensitizers or radioenhancers. While research so far has been primarily focused on gold nanoparticles and other high atomic number materials to increase the absorption cross section of tumor tissue, recent studies are challenging the traditional concept of high-Z nanoparticle radioenhancers and highlight the importance of catalytic activity. This review provides a concise overview on the knowledge of nanoparticle radioenhancement mechanisms and their quantification. It critically discusses potential radioenhancer candidate materials and general design criteria for different radiation therapy modalities, and concludes with research priorities in order to advance the development of nanomaterials, to enhance the efficacy of radiotherapy and to increase at the same time the therapeutic window.

Pharmacokinetics derived from PET imaging of inspiring radio-enhancer platinum nanoparticles

Personalized medicine approach in radiotherapy requires the delivery of precise dose to the tumor. The concept is to increase the effectiveness of radiotherapy while sparing the surrounding heathy tissue. This can be achieved by the use of high-Z metal-based nanoparticles (NPs) as radio-enhancers and PET imaging for mapping NPs distribution to guide the irradiation. In the present study, radio-enhancing platinum NPs were radiolabeled and imaged to assess their pharmacokinetics over time. PET imaging of these NPs revealed high enhanced permeation and retention effect. The maximal tumor accumulation (4.8 ± 0.8 %ID/cc) was observed at 24 h post-injection along with persistent accumulation of the NPs, especially at the tumor ring, even after several days. These properties positively suggest the potential clinical use of these NPs.

Responsive polyprodrug for anticancer nanocarriers

Nanocarriers responsive to glutathione (GSH), a molecule overexpressed in cancer cells, are extensively investigated for the delivery of Pt-based chemotherapeutics for cancer treatment.

Green Metallic Nanoparticles for Cancer Therapy: Evaluation Models and Cancer Applications

Metal-based nanoparticles are widely used to deliver bioactive molecules and drugs to improve cancer therapy. Several research works have highlighted the synthesis of gold and silver nanoparticles by green chemistry, using biological entities to minimize the use of solvents and control their physicochemical and biological properties. Recent advances in evaluating the anticancer effect of green biogenic Au and Ag nanoparticles are mainly focused on the use of conventional 2D cell culture and in vivo murine models that allow determination of the half-maximal inhibitory concentration, a critical parameter to move forward clinical trials. However, the interaction between nanoparticles and the tumor microenvironment is not yet fully understood. Therefore, it is necessary to develop more human-like evaluation models or to improve the existing ones for a better understanding of the molecular bases of cancer. This review provides recent advances in biosynthesized Au and Ag nanoparticles for seven of the most common and relevant cancers and their biological assessment. In addition, it provides a general idea of the in silico, in vitro, ex vivo, and in vivo models used for the anticancer evaluation of green biogenic metal-based nanoparticles.

Radiation Enhancer Effect of Platinum Nanoparticles in Breast Cancer Cell Lines: In Vitro and In Silico Analyses

High-Z metallic nanoparticles (NPs) are new players in the therapeutic arsenal against cancer, especially radioresistant cells. Indeed, the presence of these NPs inside malignant cells is believed to enhance the effect of ionizing radiation by locally increasing the dose deposition. In this context, the potential of platinum nanoparticles (PtNPs) as radiosensitizers was investigated in two breast cancer cell lines, T47D and MDA-MB-231, showing a different radiation sensitivity. PtNPs were internalized in the two cell lines and localized in lysosomes and multivesicular bodies. Analyses of cell responses in terms of clonogenicity, survival, mortality, cell-cycle distribution, oxidative stress, and DNA double-strand breaks did not reveal any significant enhancement effect when cells were pre-exposed to PtNPs before being irradiated, as compared to radiation alone. This result is different from that reported in a previous study performed, under the same conditions, on cervical cancer HeLa cells. This shows that the efficacy of radio-enhancement is strongly cell-type-dependent. Simulation of the early stage ionization processes, taking into account the irradiation characteristics and realistic physical parameters in the biological sample, indicated that PtNPs could weakly increase the dose deposition (by 3%) in the immediate vicinity of the nanoparticles. Some features that are potentially responsible for the biological effect could not be taken into account in the simulation. Thus, chemical and biological effects could explain this discrepancy. For instance, we showed that, in these breast cancer cell lines, PtNPs exhibited ambivalent redox properties, with an antioxidant potential which could counteract the radio-enhancement effect. This work shows that the efficacy of PtNPs for enhancing radiation effects is strongly cell-dependent and that no effect is observed in the case of the breast cancer cell lines T47D and MDA-MB-231. Thus, more extensive experiments using other relevant biological models are needed in order to evaluate such combined strategies, since several clinical trials have already demonstrated the success of combining nanoagents with radiotherapy in the treatment of a range of tumor types.