An overview of nanoscale radionuclides and radiolabeled nanomaterials commonly used for nuclear molecular imaging and therapeutic functions

Recent advances in the field of nanotechnology applications in nuclear medicine offer the promise of better diagnostic and therapeutic options. In recent years, increasing efforts have been focused on developing nanoconstructs that can be used as core platforms for attaching medical radionuclides with different strategies for the purposes of molecular imaging and targeted drug delivery. This review article presents an introduction to some commonly used nanomaterials with zero-dimensional, one-dimensional, two-dimensional, and three-dimensional structures, describes the various methods applied to radiolabeling of nanomaterials, and provides illustrative examples of application of the nanoscale radionuclides or radiolabeled nanocarriers in nuclear nanomedicine. Especially, the passive and active nanotargeting delivery of radionuclides with illustrating examples for tumor imaging and therapy was reviewed and summarized. The accurate and early diagnosis of cancer can lead to increased survival rates for different types of this disease. Although, the conventional single-modality diagnostic methods such as positron emission tomography/single photon emission computed tomography or MRI used for such purposes are powerful means; most of these are limited by sensitivity or resolution. By integrating complementary signal reporters into a single nanoparticulate contrast agent, multimodal molecular imaging can be performed as scalable images with high sensitivity, resolution, and specificity. The advent of radiolabeled nanocarriers or radioisotope-loaded nanomaterials with magnetic, plasmonic, or fluorescent properties has stimulated growing interest in the developing multimodality imaging probes. These new developments in nuclear nanomedicine are expected to introduce a paradigm shift in multimodal molecular imaging and thereby opening up an era of new diagnostic medical imaging agents. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 251-285, 2019.

68Ga@pyridine-functionalized MCM-41 mesoporous silica: a novel radio labeled composite for diagnostic applications

Silica nanoparticles (SNPs) are known as intrinsic radiolabeling agents and offer a fast and reliable approach to deliver theranostic agents into targeted organs. Radiolabeled amorphous silica nanoparticles are of great interest to radiation oncology communities. In order to improve the performance of these nano materials in cancer diagnosis and treatment, their inherent properties, such as surface area and the ability to accumulate in cancer cells, should be enhanced. Pyridine functionalized mesoporous silica MCM-41 is known as a potential anticancer-drug delivery system with high suface area. In thiswork, in order to produce an image-guided drug delivery system for diagnostic applications, [68Ga] radionuclide was grafted on pyridine functionalized MCM-41. The nanoparticles were assessed with atomic force microscopy (AFM), paper chromatography, X-ray diffraction, FTIR spectroscopy, CHN and TGA/DTA analyses. The pharmacokinetic profile evaluation of the radiolabeled nano silica, [68Ga]-Py-Butyl@MCM-41, was done in Fibrosarcoma tumor-bearing mice. This labeled nanocomposite with appropriate blood circulation in body, high structural stability, high tumor/blood ID/g% ratio and fast excretion from the body can be proposed as an efficient nano engineered composite for upcoming tumor targeting/imaging nanotechnology-based applications.

Silica and carbon decorated silica nanosheet impact on primary human immune cells

Silica nanosheets (SiO₂ NS) are considered to be a promising material in clinical practice for diagnosis and therapy applications. However, an appropriate surface functionalization is essential to guarantee high biocompatibility and molecule loading ability. Although SiO₂ NS are chemically stable, its effects on immune systems are still being explored. In this work, we successfully synthesized a novel 2D multilayer SiO₂ NS and SiO₂ NS coated with carbon (C/SiO₂ NS), and evaluated their impact on human Peripheral Blood Mononuclear Cells (PBMCs) and some immune cell subpopulations. We demonstrated that the immune response is strongly dependent on the surface functionalities of the SiO₂ NS. Ex vivo experiments showed an increase in biocompatibility of C/SiO₂ NS compared to SiO₂ NS, resulting in a lowering of hemoglobin release together with a reduction in cellular toxicity and cellular activation. However, none of them are directly involved in the activation of the acute inflammation process with a consequent release of pro-inflammatory cytokines. The obtained results provide an important direction towards the biomedical applications of silica nanosheets, rendering them an attractive material for the development of future immunological therapies.