A multifunctional black phosphorus nanosheet-based immunomagnetic bio-interface for heterogeneous circulating tumor cell capture and simultaneous self-identification in gastric cancer patients

A single epithelial cell adhesion molecule (EpCAM) for circulating tumor cell (CTCs) isolation has been proved to be low in efficiency as it fails to recognize EpCAM-negative CTCs. Meanwhile, the current immunocytochemical (ICC) identification strategy for the captured cells is tedious and time-consuming. To address these issues, we designed a dual-labeled fluorescent immunomagnetic nanoprobe (BP-Fe₃O₄-AuNR/Apt), by loading magnetic Fe₃O₄ nanoparticles and gold nanorods (AuNRs) onto black phosphorus (BP) nanosheets and then linking them with Cy3-labeled EpCAM and Texas red-labeled tyrosine protein kinase 7 (PTK7) aptamers, which created a high-performance bio-interface for efficient, heterogeneous CTC capture and rapid self-identification with high accuracy. As few as 5 CTCs could be captured from 1.0 mL PBS, mixed cell solution and lysed blood. What's more, the presence of BP and AuNRs on this capturing interface also allowed us to preliminarily investigate the potential photothermal therapeutic effect of the probe toward CTC elimination. The applicability of the probe was further demonstrated in gastric cancer patients. By detecting the number of CTCs in the blood of gastric cancer patients, the correlations between the CTC number and the disease stage, as well as distant metastasis were systematically explored.

Nanostrategies for Therapeutic and Diagnostic Targeting of Gastrin-Releasing Peptide Receptor

Advances in nanomedicine bring the attention of researchers to the molecular targets that can play a major role in the development of novel therapeutic and diagnostic modalities for cancer management. The choice of a proper molecular target can decide the efficacy of the treatment and endorse the personalized medicine approach. Gastrin-releasing peptide receptor (GRPR) is a G-protein-coupled membrane receptor, well known to be overexpressed in numerous malignancies including pancreatic, prostate, breast, lung, colon, cervical, and gastrointestinal cancers. Therefore, many research groups express a deep interest in targeting GRPR with their nanoformulations. A broad spectrum of the GRPR ligands has been described in the literature, which allows tuning of the properties of the final formulation, particularly in the field of the ligand affinity to the receptor and internalization possibilities. Hereby, the recent advances in the field of applications of various nanoplatforms that are able to reach the GRPR-expressing cells are reviewed.

Fluorescence-Raman dual-mode quantitative detection and imaging of small-molecule thiols in cell apoptosis with DNA-modified gold nanoflowers

The monitoring of small-molecule thiols (especially glutathione) has attracted widespread attention due to their involvement in numerous physiological processes in living organisms and cells. In this work, a dual-mode nanosensor was designed to detect small-molecule thiols, which is based on the "on-off" switch of fluorescence resonance energy transfer (FRET) and surface-enhanced Raman scattering (SERS). Briefly, DNA was modified by Cy5 (signal probe) and disulfide bonds (recognition element). Gold nanoflowers (AuNFs) were used as the fluorescence-quenching and SERS-enhancing substrate. However, small-molecule thiols can cleave disulfide bonds and release short Cy5-labeled chains, causing the recovery of the fluorescence signal and a decrease of the SERS signal. The nanosensor showed a sensitive response to small-molecule thiols represented by GSH, with a linear range of 0.01-3 mM and a detection limit of 913 nM. In addition, it competed with other related biological interferences and presented good stability and better selectivity towards small-molecule thiols. Most importantly, the developed nanosensor had been successfully applied to in situ imaging and quantitative monitoring of the concentration of small-molecule thiols which changed during T-2 toxin-induced apoptosis in HeLa cells. Meanwhile, nanosensors are also versatile with their potential applications and can be easily extended to the detection and imaging of other human cell lines. The proposed method combines the dual advantages of fluorescence and SERS, which has broad prospects for in situ studies of physiological processes involving small-molecule thiols in biological systems.

Advances in Development of Radiometal Labeled Amino Acid-Based Compounds for Cancer Imaging and Diagnostics

Radiolabeled biomolecules targeted at tumor-specific enzymes, receptors, and transporters in cancer cells represent an intensively investigated and promising class of molecular tools for the cancer diagnosis and therapy. High specificity of such biomolecules is a prerequisite for the treatment with a lower burden to normal cells and for the effective and targeted imaging and diagnosis. Undoubtedly, early detection is a key factor in efficient dealing with many severe tumor types. This review provides an overview and critical evaluation of novel approaches in the designing of target-specific probes labeled with metal radionuclides for the diagnosis of most common death-causing cancers, published mainly within the last three years. Advances are discussed such traditional peptide radiolabeling approaches, and click and nanoparticle chemistry. The progress of radiolabeled peptide based ligands as potential radiopharmaceuticals is illustrated via novel structure and application studies, showing how the molecular modifications reflect their binding selectivity to significant onco-receptors, toxicity, and, by that, practical utilization. The most impressive outputs in categories of newly developed structures, as well as imaging and diagnosis approaches, and the most intensively studied oncological diseases in this context, are emphasized in order to show future perspectives of radiometal labeled amino acid-based compounds in nuclear medicine.

Radiolabelling of nanomaterials for medical imaging and therapy

Nanomaterials offer unique physical, chemical and biological properties of interest for medical imaging and therapy. Over the last two decades, there has been an increasing effort to translate nanomaterial-based medicinal products (so-called nanomedicines) into clinical practice and, although multiple nanoparticle-based formulations are clinically available, there is still a disparity between the number of pre-clinical products and those that reach clinical approval. To facilitate the efficient clinical translation of nanomedicinal-drugs, it is important to study their whole-body biodistribution and pharmacokinetics from the early stages of their development. Integrating this knowledge with that of their therapeutic profile and/or toxicity should provide a powerful combination to efficiently inform nanomedicine trials and allow early selection of the most promising candidates. In this context, radiolabelling nanomaterials allows whole-body and non-invasive in vivo tracking by the sensitive clinical imaging techniques positron emission tomography (PET), and single photon emission computed tomography (SPECT). Furthermore, certain radionuclides with specific nuclear emissions can elicit therapeutic effects by themselves, leading to radionuclide-based therapy. To ensure robust information during the development of nanomaterials for PET/SPECT imaging and/or radionuclide therapy, selection of the most appropriate radiolabelling method and knowledge of its limitations are critical. Different radiolabelling strategies are available depending on the type of material, the radionuclide and/or the final application. In this review we describe the different radiolabelling strategies currently available, with a critical vision over their advantages and disadvantages. The final aim is to review the most relevant and up-to-date knowledge available in this field, and support the efficient clinical translation of future nanomedicinal products for in vivo imaging and/or therapy.

Radiolabeled Gold Nanoparticles for Imaging and Therapy of Cancer

In the Last decades, nanotechnology has provided novel and alternative methodologies and tools in the field of medical oncology, in order to tackle the issues regarding the control and treatment of cancer in modern society. In particular, the use of gold nanoparticles (AuNPs) in radiopharmaceutical development has provided various nanometric platforms for the delivery of medically relevant radioisotopes for SPECT/PET diagnosis and/or radionuclide therapy. In this review, we intend to provide insight on the methodologies used to obtain and characterize radiolabeled AuNPs while reporting relevant examples of AuNPs developed during the last decade for applications in nuclear imaging and/or radionuclide therapy, and highlighting the most significant preclinical studies and results.

Dual Imaging Gold Nanoplatforms for Targeted Radiotheranostics

Gold nanoparticles (AuNPs) are interesting for the design of new cancer theranostic tools, mainly due to their biocompatibility, easy molecular vectorization, and good biological half-life. Herein, we report a gold nanoparticle platform as a bimodal imaging probe, capable of coordinating Gd³⁺ for Magnetic Resonance Imaging (MRI) and ⁶⁷Ga³⁺ for Single Photon Emission Computed Tomography (SPECT) imaging. Our AuNPs carry a bombesin analogue with affinity towards the gastrin releasing peptide receptor (GRPr), overexpressed in a variety of human cancer cells, namely PC3 prostate cancer cells. The potential of these multimodal imaging nanoconstructs was thoroughly investigated by the assessment of their magnetic properties, in vitro cellular uptake, biodistribution, and radiosensitisation assays. The relaxometric properties predict a potential T₁- and T₂- MRI application. The promising in vitro cellular uptake of ⁶⁷Ga/Gd-based bombesin containing particles was confirmed through biodistribution studies in tumor bearing mice, indicating their integrity and ability to target the GRPr. Radiosensitization studies revealed the therapeutic potential of the nanoparticles. Moreover, the DOTA chelating unit moiety versatility gives a high theranostic potential through the coordination of other therapeutically interesting radiometals. Altogether, our nanoparticles are interesting nanomaterial for theranostic application and as bimodal T₁- and T₂- MRI / SPECT imaging probes.

Gold Nanoparticles in Radiotherapy and Recent Progress in Nanobrachytherapy

Over the last few decades, gold nanoparticles (GNPs) have emerged as "radiosensitizers" in oncology. Radiosensitizers are additives that can enhance the effects of radiation on biological tissues treated with radiotherapy. The interaction of photons with GNPs leads to the emission of low-energy and short-range secondary electrons, which in turn increase the dose deposited in tissues. In this context, GNPs are the subject of intensive theoretical and experimental studies aiming at optimizing the parameters leading to greater dose enhancement and highest therapeutic effect. This review describes the main mechanisms occurring between photons and GNPs that lead to dose enhancement. The outcome of theoretical simulations of the interactions between GNPs and photons is presented. Finally, the findings of the most recent in vivo studies about interactions between GNPs and photon sources (e.g., external beams, brachytherapy sources, and molecules labeled with radioisotopes) are described. The advantages and challenges inherent to each of these approaches are discussed. Future directions, providing new guidelines for the successful translation of GNPs into clinical applications, are also highlighted.

Decorated Superparamagnetic Iron Oxide Nanoparticles with Monoclonal Antibody and Diethylene-Triamine-Pentaacetic Acid Labeled with Thechnetium-99m and Galium-68 for Breast Cancer Imaging

PURPOSE

In this study we developed and tested an iron oxide nanoparticle conjugated with DTPA and Trastuzumab, which can efficiently be radiolabeled with 99m-Tc and Ga-68, generating a nanoradiopharmaceutical agent to be used for SPECT and PET imaging.

METHODS

The production of iron oxide nanoparticle conjugated with DTPA and Trastuzumab was made using phosphorylethanolamine (PEA) surface modification. Both radiolabeling process was made by the direct radiolabeling of the nanoparticles. The in vivo assay was done in female Balb/c nude mice xenografted with breast cancer. Also a planar imaging using the radiolabeled nanoparticle was performed.

RESULTS

No thrombus and immune response leading to unwanted interaction and incorporation of nanoparticles by endothelium and organs, except filtration by the kidneys, was observed. In fact, more than 80% of ^99mTc-DTPA-TZMB@Fe₃O₄ nanoparticles seems to be cleared by the renal pathway but the implanted tumor whose seems to increase the expression of HER2 receptors enhancing the uptake by all other organs.

CONCLUSION

However, even in this unfavorable situation the tumor bioconcentrated much larger amounts of the nano-agent than normal tissues giving clear enough contrast for breast cancer imaging for diagnostics purpose by both SPECT and PET technique. Graphical Abstract ᅟ.