68Ga-radiolabeled bombesin-conjugated to trimethyl chitosan-coated superparamagnetic nanoparticles for molecular imaging: preparation, characterization and biological evaluation

Multifunctional polysaccharide nanoprobes for biological imaging

Imaging and tracking biological targets or processes play an important role in revealing molecular mechanisms and disease states. Bioimaging via optical, nuclear, or magnetic resonance techniques enables high resolution, high sensitivity, and high depth imaging from the whole animal down to single cells via advanced functional nanoprobes. To overcome the limitations of single-modality imaging, multimodality nanoprobes have been engineered with a variety of imaging modalities and functionalities. Polysaccharides are sugar-containing bioactive polymers with superior biocompatibility, biodegradability, and solubility. The combination of polysaccharides with single or multiple contrast agents facilitates the development of novel nanoprobes with enhanced functions for biological imaging. Nanoprobes constructed with clinically applicable polysaccharides and contrast agents hold great potential for clinical translations. This review briefly introduces the basics of different imaging modalities and polysaccharides, then summarizes the recent progress of polysaccharide-based nanoprobes for biological imaging in various diseases, emphasizing bioimaging with optical, nuclear, and magnetic resonance techniques. The current issues and future directions regarding the development and applications of polysaccharide nanoprobes are further discussed.

Peptide-based diagnostic and therapeutic agents: Where we are and where we are heading?

Peptides are increasingly present in all branches of medicine as innovative drugs, imaging agents, theragnostic, and constituent moieties of other sophisticated drugs such as peptide-drug conjugates. Due to new developments in chemical synthesis strategies, computational biology, recombinant technology, and chemical biology, peptide drug development has made a great progress in the last decade. Numerous natural peptides and peptide mimics have been obtained and studied, covering multiple therapeutic areas. Even though peptides have been investigated across the wide therapeutic spectrum, oncology, metabolism, and endocrinology are the most frequent medical indications of them. This review summarizes the current use of and the emerging new opportunities of peptides for diagnosis and treatment of various diseases.

Nanoparticle biodistribution coefficients: A quantitative approach for understanding the tissue distribution of nanoparticles

The objective of this manuscript is to provide quantitative insights into the tissue distribution of nanoparticles. Published pharmacokinetics of nanoparticles in plasma, tumor and 13 different tissues of mice were collected from literature. A total of 2018 datasets were analyzed and biodistribution of graphene oxide, lipid, polymeric, silica, iron oxide and gold nanoparticles in different tissues was quantitatively characterized using Nanoparticle Biodistribution Coefficients (NBC). It was observed that typically after intravenous administration most of the nanoparticles are accumulated in the liver (NBC = 17.56 %ID/g) and spleen (NBC = 12.1 %ID/g), while other tissues received less than 5 %ID/g. NBC values for kidney, lungs, heart, bones, brain, stomach, intestine, pancreas, skin, muscle and tumor were found to be 3.1 %ID/g, 2.8 %ID/g, 1.8 %ID/g, 0.9 %ID/g, 0.3 %ID/g, 1.2 %ID/g, 1.8 %ID/g, 1.2 %ID/g, 1.0 %ID/g, 0.6 %ID/g and 3.4 %ID/g, respectively. Significant variability in nanoparticle distribution was observed in certain organs such as liver, spleen and lungs. A large fraction of this variability could be explained by accounting for the differences in nanoparticle physicochemical properties such as size and material. A critical overview of published nanoparticle physiologically-based pharmacokinetic (PBPK) models is provided, and limitations in our current knowledge about in vitro and in vivo pharmacokinetics of nanoparticles that restrict the development of robust PBPK models is also discussed. It is hypothesized that robust quantitative assessment of whole-body pharmacokinetics of nanoparticles and development of mathematical models that can predict their disposition can improve the probability of successful clinical translation of these modalities.

68Ga radiolabeled chitosan/curcumin/biotin nanocomposite as a drug carrier and early-stage cancer detection

Nano chitosan was extracted from shrimp wastes. Biotin, as a tumor-targeting agent, and curcumin, as potential carriers of ⁶⁸Ga, were immobilized on the nano chitosan, and a novel bio-nanocomposite was designed. It was characterized by FT-IR, SEM, TEM, XRD, TGA, and elemental analysis. It seems that the chitosan has a fibril shape with an average size of 70 nm, and the biotin and curcumin are evenly distributed as obtained SEM images. While, the size of Chit/Cur@Biot bio-nanocomposite was between 10 and 20 nm according to the TEM images. Cell cytotoxicity assay, cellular uptake, and fluorescence spectroscopy on A549 lung cancer cells were performed to show the potential applications of this bio-nanocomposite. The obtained results were demonstrated that Chit/Cur and Chit/Cur@Biot bio-nanocomposite exhibit antitumor activity, while, the Chit/Cur@Biot bio-nanocomposite is more effective than Chit/Cur against cancer cell lines at high concentrations. The results of fluoresce microscopy show that fluoresce of Chit/Cur@Biot was much stronger than Chit/Cur in the A549 cell lines. Moreover, the cellular uptake of Chit/Cur@Biot was enhanced when compared with the control group. The potentials of this bio-nanocomposite as anticancer and cancer-detecting agent in nuclear medicine were confirmed.

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.

Radiolabeled Iron Oxide Nanoparticles as Dual Modality Contrast Agents in SPECT/MRI and PET/MRI

During the last decades, the utilization of imaging modalities such as single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance imaging (MRI) in every day clinical practice has enabled clinicians to diagnose diseases accurately at early stages. Radiolabeled iron oxide nanoparticles (RIONs) combine their intrinsic magnetic behavior with the extrinsic character of the radionuclide additive, so that they constitute a platform of multifaceted physical properties. Thus, at a practical level, RIONs serve as the physical parent of the so-called dual-modality contrast agents (DMCAs) utilized in SPECT/MRI and PET/MRI applications due to their ability to combine, at real time, the high sensitivity of SPECT or PET together with the high spatial resolution of MRI. This review focuses on the synthesis and in vivo investigation of both biodistribution and imaging efficacy of RIONs as potential SPECT/MRI or PET/MRI DMCAs.

Amyloid-β PET in Alzheimer's disease: A systematic review and Bayesian meta-analysis

BACKGROUND

In recent years, longitudinal studies of Alzheimer's disease (AD) have been successively concluded. Our aim is to determine the efficacy of amyloid-β (Aβ) PET in diagnosing AD and early prediction of mild cognitive impairment (MCI) converting to AD. By pooling studies from different centers to explore in-depth whether diagnostic performance varies by population type, radiotracer type, and diagnostic approach, thus providing a more comprehensive theoretical basis for the subsequent widespread application of Aβ PET in the clinical setting.

METHODS

Relevant studies were searched through PubMed. The pooled sensitivities, specificities, DOR, and the summary ROC curve were obtained based on a Bayesian random-effects model.

RESULTS

Forty-eight studies, including 5967 patients, were included. Overall, the pooled sensitivity, specificity, DOR, and AUC of Aβ PET for diagnosing AD were 0.90, 0.80, 35.68, and 0.91, respectively. Subgroup analysis showed that Aβ PET had high sensitivity (0.91) and specificity (0.81) for differentiating AD from normal controls but very poor specificity (0.49) for determining AD from MCI. The pooled sensitivity and specificity were 0.84 and 0.62, respectively, for predicting the conversion of MCI to AD. The differences in diagnostic efficacy between visual assessment and quantitative analysis and between ¹¹ C-PIB PET and ¹⁸ F-florbetapir PET were insignificant.

CONCLUSIONS

The overall performance of Aβ PET in diagnosing AD is favorable, but the differentiation between MCI and AD patients should consider that some MCI may be at risk of conversion to AD and may be misdiagnosed. A multimodal diagnostic approach and machine learning analysis may be effective in improving diagnostic accuracy.

Preclinical PET and MR Evaluation of 89Zr- and 68Ga-Labeled Nanodiamonds in Mice over Different Time Scales

Nanodiamonds (NDs) have high potential as a drug carrier and in combination with nitrogen vacancies (NV centers) for highly sensitive MR-imaging after hyperpolarization. However, little remains known about their physiological properties in vivo. PET imaging allows further evaluation due to its quantitative properties and high sensitivity. Thus, we aimed to create a preclinical platform for PET and MR evaluation of surface-modified NDs by radiolabeling with both short- and long-lived radiotracers. Serum albumin coated NDs, functionalized with PEG groups and the chelator deferoxamine, were labeled either with zirconium-89 or gallium-68. Their biodistribution was assessed in two different mouse strains. PET scans were performed at various time points up to 7 d after i.v. injection. Anatomical correlation was provided by additional MRI in a subset of animals. PET results were validated by ex vivo quantification of the excised organs using a gamma counter. Radiolabeled NDs accumulated rapidly in the liver and spleen with a slight increase over time, while rapid washout from the blood pool was observed. Significant differences between the investigated radionuclides were only observed for the spleen (1 h). In summary, we successfully created a preclinical PET and MR imaging platform for the evaluation of the biodistribution of NDs over different time scales.

Toxicity Assessment of [177Lu]Lu-iFAP/iPSMA Nanoparticles Prepared under GMP-Compliant Radiopharmaceutical Processes

The fibroblast activation protein (FAP) is heavily expressed in fibroblasts associated with the tumor microenvironment, while the prostate-specific membrane antigen (PSMA) is expressed in the neovasculature of malignant angiogenic processes. Previously, we reported that [¹⁷⁷Lu]lutetium sesquioxide-iFAP/iPSMA nanoparticles ([¹⁷⁷Lu]Lu-iFAP/iPSMA) inhibit HCT116 tumor progression in mice. Understanding the toxicity of [¹⁷⁷Lu]Lu-iFAP/iPSMA in healthy tissues, as well as at the tissue and cellular level in pathological settings, is essential to demonstrate the nanosystem safety for treating patients. It is equally important to demonstrate that [¹⁷⁷Lu]Lu-iFAP/iPSMA can be prepared under good manufacturing practices (GMP) with reproducible pharmaceutical-grade quality characteristics. This research aimed to prepare [¹⁷⁷Lu]Lu-iFAP/iPSMA under GMP-compliant radiopharmaceutical processes and evaluate its toxicity in cell cultures and murine biological systems under pathological environments. [¹⁷⁷Lu]Lu₂O₃ nanoparticles were formulated as radiocolloidal solutions with FAP and PSMA inhibitor ligands (iFAP and iPSMA), sodium citrate, and gelatin, followed by heating at 121 °C (103-kPa pressure) for 15 min. Three consecutive batches were manufactured. The final product was analyzed according to conventional pharmacopeial methods. The Lu content in the formulations was determined by X-ray fluorescence. [¹⁷⁷Lu]Lu-iFAP/iPSMA performance in cancer cells was evaluated in vitro by immunofluorescence. Histopathological toxicity in healthy and tumor tissues was assessed in HCT116 tumor-bearing mice. Immunohistochemical assays were performed to corroborate FAP and PSMA tumor expression. Acute genotoxicity was evaluated using the micronuclei assay. The results showed that the batches manufactured under GMP conditions were reproducible. Radiocolloidal solutions were sterile and free of bacterial endotoxins, with radionuclidic and radiochemical purity greater than 99%. The lutetium content was 0.10 ± 0.02 mg/mL (0.9 GBq/mg). Significant inhibition of cell proliferation in vitro and in tumors was observed due to the accumulation of nanoparticles in the fibroblasts (FAP+) and neovasculature (PSMA+) of the tumor microenvironment. No histopathological damage was detected in healthy tissues. The data obtained in this research provide new evidence on the selective toxicity to malignant tumors and the absence of histological changes in healthy tissues after intravenous injection of [¹⁷⁷Lu]Lu-iFAP/iPSMA in mammalian hosts. The easy preparation under GMP conditions and the toxicity features provide the added value needed for [¹⁷⁷Lu]Lu-iFAP/iPSMA clinical translation.

Methods for Radiolabelling Nanoparticles: PET Use (Part 2)

The use of radiolabelled nanoparticles (NPs) is a promising nuclear medicine tool for diagnostic and therapeutic purposes. Thanks to the heterogeneity of their material (organic or inorganic) and their unique physical and chemical characteristics, they are highly versatile for their use in several medical applications. In particular, they have shown interesting results as radiolabelled probes for positron emission tomography (PET) imaging. The high variability of NP types and the possibility to use several isotopes in the radiolabelling process implies different radiolabelling methods that have been applied over the previous years. In this review, we compare and summarize the different methods for NP radiolabelling with the most frequently used PET isotopes.

IAEA Contribution to Nanosized Targeted Radiopharmaceuticals for Drug Delivery

The rapidly growing interest in the application of nanoscience in the future design of radiopharmaceuticals and the development of nanosized radiopharmaceuticals in the late 2000′s, resulted in the creation of a Coordinated Research Project (CRP) by the International Atomic Energy Agency (IAEA) in 2014. This CRP entitled ‘Nanosized delivery systems for radiopharmaceuticals’ involved a team of expert scientist from various member states. This team of scientists worked on a number of cutting-edge areas of nanoscience with a focus on developing well-defined, highly effective and site-specific delivery systems of radiopharmaceuticals. Specifically, focus areas of various teams of scientists comprised of the development of nanoparticles (NPs) based on metals, polymers, and gels, and their conjugation/encapsulation or decoration with various tumor avid ligands such as peptides, folates, and small molecule phytochemicals. The research and development efforts also comprised of developing optimum radiolabeling methods of various nano vectors using diagnostic and therapeutic radionuclides including Tc-99m, Ga-68, Lu-177 and Au-198. Concerted efforts of teams of scientists within this CRP has resulted in the development of various protocols and guidelines on delivery systems of nanoradiopharmaceuticals, training of numerous graduate students/post-doctoral fellows and publications in peer reviewed journals while establishing numerous productive scientific networks in various participating member states. Some of the innovative nanoconstructs were chosen for further preclinical applications—all aimed at ultimate clinical translation for treating human cancer patients. This review article summarizes outcomes of this major international scientific endeavor.

Trimethyl-Chitosan Coated Gold Nanoparticles Enhance Delivery, Cellular Uptake and Gene Silencing Effect of EGFR-siRNA in Breast Cancer Cells

Purpose: Despite the promising therapeutic effects of gene silencing with small interfering RNAs (siRNAs), the challenges associated with delivery of siRNAs to the tumor cells in vivo, has greatly limited its clinical application. To overcome these challenges, we employed gold nanoparticles modified with trimethyl chitosan (TMC) as an effective delivery carrier to improve the stability and cellular uptake of siRNAs against epidermal growth factor receptor (EGFR) that is implicated in breast cancer. Methods: AuNPs were prepared by the simple aqueous reduction of chloroauric acid (HAuCl₄) with ascorbic acid and coated with synthesized TMC. EGFR-siRNA was then complexed with the AuNPs-TMC via electrostatic interaction to make AuNPs-TMC/EGFR-siRNA with a w/w ratio of 10:1. Nanoparticles were assessed for physicochemical characteristics and in vitro cellular behavior on MCF-7 breast cancer cell line. Results: Spherical and positively charged AuNPs-TMC (67 nm, +45 mV) were successfully complexed with EGFR-siRNA (82 nm, +11 mV) which were able to retard the gene migration completely. Confocal microscopy and flow cytometry analysis demonstrated complete cellular uptake of Cy5 labeled AuNPs-TMC in the MCF-7 cells after 4 h incubation. MTT test after 48 h incubation showed that the AuNPs-TMC were safe but when combined with EGFR-siRNA exert significant cytotoxicity while the cell viability was about 50%. These nanocomplexes also showed a high gene expression knockdown (86%) of EGFR and also a high apoptosis rate (Q2 + Q3 = 18.5%) after 24 h incubation. Conclusion: This study suggests that the simply synthesized AuNPs-TMC are novel, effective, and promising nanocarriers for siRNA delivery, and AuNPs-TMC/EGFR-siRNA appears to be a potential therapeutic agent for breast cancer treatment.

Biomedical Applications of Iron Oxide Nanoparticles: Current Insights Progress and Perspectives

The enormous development of nanomaterials technology and the immediate response of many areas of science, research, and practice to their possible application has led to the publication of thousands of scientific papers, books, and reports. This vast amount of information requires careful classification and order, especially for specifically targeted practical needs. Therefore, the present review aims to summarize to some extent the role of iron oxide nanoparticles in biomedical research. Summarizing the fundamental properties of the magnetic iron oxide nanoparticles, the review's next focus was to classify research studies related to applying these particles for cancer diagnostics and therapy (similar to photothermal therapy, hyperthermia), in nano theranostics, multimodal therapy. Special attention is paid to research studies dealing with the opportunities of combining different nanomaterials to achieve optimal systems for biomedical application. In this regard, original data about the synthesis and characterization of nanolipidic magnetic hybrid systems are included as an example. The last section of the review is dedicated to the capacities of magnetite-based magnetic nanoparticles for the management of oncological diseases.

Recent Advances in Brachytherapy Using Radioactive Nanoparticles: An Alternative to Seed-Based Brachytherapy

Interstitial brachytherapy (BT) is generally used for the treatment of well-confined solid tumors. One example of this is in the treatment of prostate tumors by permanent placement of radioactive seeds within the prostate gland, where low doses of radiation are delivered for several months. However, successful implementation of this technique is hampered due to several posttreatment adverse effects or symptoms and operational and logistical complications associated with it. Recently, with the advancements in nanotechnology, radioactive nanoparticles (radio-NPs) functionalized with tumor-specific biomolecules, injected intratumorally, have been reported as an alternative to seed-based BT. Successful treatment of solid tumors using radio-NPs has been reported in several preclinical studies, on both mice and canine models. In this article, we review the recent advancements in the synthesis and use of radio-NPs as a substitute to seed-based BT. Here, we discuss the limitations of current seed-based BT and advantages of radio-NPs for BT applications. Recent progress on the types of radio-NPs, their features, synthesis methods, and delivery techniques are discussed. The last part of the review focuses on the currently used dosimetry protocols and studies on the dosimetry of nanobrachytherapy applications using radio-NPs. The current challenges and future research directions on the role of radio-NPs in BT treatments are also discussed.

Chitosan: A versatile bio-platform for breast cancer theranostics

Breast cancer is considered one of the utmost neoplastic diseases globally, with a high death rate of patients. Over the last decades, many approaches have been studied to early diagnose and treat it, such as chemotherapy, hormone therapy, immunotherapy, and MRI and biomarker tests; do not show the optimal efficacy. These existing approaches are accompanied by severe side effects, thus recognizing these challenges, a great effort has been done to find out the new remedies for breast cancer. Main finding: Nanotechnology opened a new horizon to the treatment of breast cancer. Many nanoparticulate platforms for the diagnosis of involved biomarkers and delivering antineoplastic drugs are under either clinical trials or just approved by the Food and Drug Administration (FDA). It is well known that natural phytochemicals are successfully useful to treat breast cancer because these natural compounds are safer, available, cheaper, and have less toxic effects. Chitosan is a biocompatible and biodegradable polymer. Further, it has outstanding features, like chemical functional groups that can easily modify our interest with an exceptional choice of promising applications. Abundant studies were directed to assess the chitosan derivative-based nanoformulation's abilities in delivering varieties of drugs. However, the role of chitosan in diagnostics and theranostics not be obligated. The present servey will discuss the application of chitosan as an anticancer drug carrier such as tamoxifen, doxorubicin, paclitaxel, docetaxel, etc. and also, its role as a theranostics (i.e. photo-responsive and thermo-responsive) moieties. The therapeutic and theranostic potential of chitosan in cancer is promising and it seems that to have a good potential to get to the clinic.

Pharmacokinetics, tissue distribution and peritoneal retention of Ag2S quantum dots following intraperitoneal administration to mice

OBJECTIVES

To investigate the pharmacokinetics, biodistribution and peritoneal retention of Ag2S quantum dots (Qds) after intraperitoneal (IP) injection into mice and to compare the results with those reported for the intravenous (IV) injection of these particles.

METHODS

Ag2S Qds was prepared by a simple one-step co-precipitation method and was injected intraperitoneally into mice. Six animals were sacrificed at predetermined time points, and blood, peritoneal content and tissue samples were collected. Ag concentration that represents the concentration of Qds was analysed by atomic absorption spectrophotometry.

KEY FINDINGS

Detectability of Qds in the peritoneal sample up to 2 h indicated that, compared with small drug molecules, the absorption of Ag2S Qds from the peritoneal cavity occurred at a slower rate. The AUC tissue/AUC blood ratio in the liver and intestine after IP injection (0.55 and 0.98, respectively) was considerably lower than those for the bolus injection (217 and 94, respectively), while this ratio in the spleen and lungs was markedly higher than the IV route.

CONCLUSIONS

Overall, the obtained results suggest that IP injection of Ag2S Qds could be more effective for drug delivery to/imaging of the spleen and lungs, whereas the IV injection for the drug delivery to/imaging of the liver and intestine.

Bombesin Peptide Conjugated Water-Soluble Chitosan Gallate-A New Nanopharmaceutical Architecture for the Rapid One-Pot Synthesis of Prostate Tumor Targeted Gold Nanoparticles

PURPOSE

We report herein bombesin peptide conjugated water-soluble chitosan gallate as a template for rapid one-pot synthesis of gold nanoparticles (AuNPs) with capabilities to target receptors on prostate cancer cells.

METHODS

Water-soluble chitosan (WCS), anchored with gallic acid (GA) and LyslLys3 (1,4,7,10-tetraazacyclo dodecane-1,4,7,10-tetraacetic acid) bombesin 1-14 (DBBN) peptide, provides a tumor targeting nanomedicine agent. WCS nanoplatforms provide attractive strategies with built-in capabilities to reduce gold (III) to gold nanoparticles with stabilizing and tumor-targeting capabilities. WCS-GA-DBBN encapsulation around gold nanoparticles affords optimum in vitro stability.

RESULTS

The DBBN content in the WCS-GA-DBBN sample was ~27%w/w. The antioxidant activities of WCS-GA and WCS-GA-DBBN nanocolloids were enhanced by 12 times as compared to the nascent WCS. AuNPs with a desirable hydrodynamic diameter range of 40-60 nm have been efficiently synthesized using WCS-GA and WCS-GA-DBBN platforms. The AuNPs were stable over 4 days after preparation and ~3 days after subjecting to all relevant biological fluids. The AuNPs capped with WCS-GA-DBBN peptide exhibited superior cellular internalization into prostate tumor (PC-3) cells with evidence of receptor mediated endocytosis.

CONCLUSION

The AuNPs capped with WCS-GA-DBBN exhibited selective affinity toward prostate cancer cells. AuNPs conjugated with WCS-GA-DBBN serve as a new generation of theranostic agents for treating various neoplastic diseases, thus opening-up new applications in oncology.

Radioactive polymeric nanoparticles for biomedical application

Nowadays, emerging radiolabeled nanosystems are revolutionizing medicine in terms of diagnostics, treatment, and theranostics. These radionuclides include polymeric nanoparticles (NPs), liposomal carriers, dendrimers, magnetic iron oxide NPs, silica NPs, carbon nanotubes, and inorganic metal-based nanoformulations. Between these nano-platforms, polymeric NPs have gained attention in the biomedical field due to their excellent properties, such as their surface to mass ratio, quantum properties, biodegradability, low toxicity, and ability to absorb and carry other molecules. In addition, NPs are capable of carrying high payloads of radionuclides which can be used for diagnostic, treatment, and theranostics depending on the radioactive material linked. The radiolabeling process of nanoparticles can be performed by direct or indirect labeling process. In both cases, the most appropriate must be selected in order to keep the targeting properties as preserved as possible. In addition, radionuclide therapy has the advantage of delivering a highly concentrated absorbed dose to the targeted tissue while sparing the surrounding healthy tissues. Said another way, radioactive polymeric NPs represent a promising prospect in the treatment and diagnostics of cardiovascular diseases such as cardiac ischemia, infectious diseases such as tuberculosis, and other type of cancer cells or tumors.

Synthesis and Properties of Targeted Radioisotope Carriers Based on Poly(Acrylic Acid) Nanogels

Radiation crosslinking was employed to obtain nanocarriers based on poly(acrylic acid)—PAA—for targeted delivery of radioactive isotopes. These nanocarriers are internally crosslinked hydrophilic macromolecules—nanogels—bearing carboxylic groups to facilitate functionalization. PAA nanogels were conjugated with an engineered bombesin-derivative—oligopeptide combined with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate chelating moiety, aimed to provide selective radioligand transport. 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) toluene-4-sulfonate was used as the coupling agent. After tests on a model amine—p-toluidine—both commercial and home-synthesized DOTA-bombesin were successfully coupled to the nanogels and the obtained products were characterized. The radiolabeling efficiency of nanocarriers with ¹⁷⁷Lu, was chromatographically tested. The results provide a proof of concept for the synthesis of radiation-synthesized nanogel-based radioisotope nanocarriers for theranostic applications.

Transarterial Radioembolization Agents: a Review of the Radionuclide Agents and the Carriers

Liver tumors, both primary and secondary to metastatic disease, remain a major challenge, with an increasing incidence. In this context, taking advantage of the dual blood supply of the liver, and the fact that liver tumors derive majority of their blood supply from the hepatic artery, intraarterial therapies are gaining popularity. Intraarterial liver-directed therapy (IALDT) is the option when the surgery is not feasible due to the number of metastases or for other reasons. Transarterial radioembolization (TARE) is a specific type of IALDT, where a carrier particle/microsphere is labeled with a radioactive substance and then is injected into hepatic artery for therapeutic purposes. As this field is rapidly evolving, with multiple agents being investigated and being introduced into clinical practice, it is hard for the practitioners and researchers to encompass all the available information concisely. This article aims to present a comprehensive review of the prominent TARE technologies.

Imaging Constructs: The Rise of Iron Oxide Nanoparticles

Over the last decade, an important challenge in nanomedicine imaging has been the work to design multifunctional agents that can be detected by single and/or multimodal techniques. Among the broad spectrum of nanoscale materials being investigated for imaging use, iron oxide nanoparticles have gained significant attention due to their intrinsic magnetic properties, low toxicity, large magnetic moments, superparamagnetic behaviour and large surface area-the latter being a particular advantage in its conjunction with specific moieties, dye molecules, and imaging probes. Tracers-based nanoparticles are promising candidates, since they combine synergistic advantages for non-invasive, highly sensitive, high-resolution, and quantitative imaging on different modalities. This study represents an overview of current advancements in magnetic materials with clinical potential that will hopefully provide an effective system for diagnosis in the near future. Further exploration is still needed to reveal their potential as promising candidates from simple functionalization of metal oxide nanomaterials up to medical imaging.

Recent nanotheranostics applications for cancer therapy and diagnosis: A review

Nanotheranostics has attracted much attention due to its widespread application in molecular imaging and cancer therapy. Molecular imaging using nanoparticles has attracted special attention in the diagnosis of cancer at early stages. With the progress made in nanotheranostics, studying drug release, accumulation in the target tissue, biodistribution, and treatment effectiveness are other important factors. However, according to the studies conducted in this regard, each nanoparticle has some advantages and limitations that should be examined and then used in clinical applications. The main goal of this review is to explore the recent advancements in nanotheranostics for cancer therapy and diagnosis. Then, it is attempted to present recent studies on nanotheranostics used as a contrast agent in various imaging modalities and a platform for cancer therapy.

Water-Soluble Chitosan Conjugated DOTA-Bombesin Peptide Capped Gold Nanoparticles as a Targeted Therapeutic Agent for Prostate Cancer

Introduction

Functionalization of water-soluble chitosan (WSCS) nanocolloids with, gold nanoparticles (AuNPs), and LyslLys3 (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-bombesin 1–14 (DOTA-BBN) peptide affords an innovative pathway to produce prostate tumor cell-specific nanomedicine agents with potential applications in molecular imaging and therapy.

Methods

The preparation involves the production and full characterization of water-soluble chitosan (WSCS), via gamma (γ) rays (80 kGy) irradiation, followed by DOTA-BBN conjugation for subsequent use as an effective template toward the synthesis of tumor cell-specific AuNPs-WSCS-DOTA-BBN.

Results

The WSCS-DOTA-BBN polymeric nanoparticles (86 ± 2.03 nm) served multiple roles as reducing and stabilizing agents in the overall template synthesis of tumor cell-targeted AuNPs. The AuNPs capped with WSCS and WSCS-DOTA-BBN exhibited average Au-core diameter of 17 ± 8 nm and 20 ± 7 nm with hydrodynamic diameters of 56 ± 1 and 67± 2 nm, respectively. The AuNPs-WSCS-DOTA-BBN showed optimum in vitro stability in biologically relevant solutions. The targeted AuNPs showed selective affinity toward GRP receptors overexpressed in prostate cancer cells (PC-3 and LNCaP).

Discussion

The AuNPs-WSCS-DOTA-BBN displayed cytotoxicity effects against PC-3 and LNCaP cancer cells, with concomitant safety toward the HAECs normal cells. The AuNPs-WSCS-DOTA-BBN showed synergistic targeting toward tumor cells with selective cytotoxicity of AuNPs towards PC-3 and LNCaP cells. Our investigations provide compelling evidence that AuNPs functionalized with WSCS-DOTA-BBN is an innovative nanomedicine approach for use in molecular imaging and therapy of GRP receptor-positive tumors. The template synthesis of AuNPs-WSCS-DOTA-BBN serves as an excellent non-radioactive surrogate for the development of the corresponding ¹⁹⁸AuNPs theragnostic nanoradiopharmaceutical for use in cancer diagnosis and therapy.

Peptide-Chitosan Engineered Scaffolds for Biomedical Applications

Peptides are signaling epitopes that control many vital biological events. Increased specificity, synthetic feasibility with concomitant lack of toxicity, and immunogenicity make this emerging class of biomolecules suitable for different applications including therapeutics, diagnostics, and biomedical engineering. Further, chitosan, a naturally occurring linear polymer composed of d-glucosamine and N-acetyl-d-glucosamine units, possesses anti-microbial, muco-adhesive, and hemostatic properties along with excellent biocompatibility. As a result, chitosan finds application in drug/gene delivery, tissue engineering, and bioimaging. Despite these applications, chitosan demonstrates limited cell adhesion and lacks biosignaling. Therefore, peptide-chitosan hybrids have emerged as a new class of biomaterial with improved biosignaling properties and cell adhesion properties. As a result, recent studies encompass increased application of peptide-chitosan hybrids as composites or conjugates in drug delivery, cell therapy, and tissue engineering and as anti-microbial material. This review discusses the recent investigations involving chitosan-peptide materials and uncovers various aspects of these interesting hybrid materials for biomedical applications.

Blockade of HIF-1α and STAT3 by hyaluronate-conjugated TAT-chitosan-SPION nanoparticles loaded with siRNA molecules prevents tumor growth

HIF-1α and STAT3 are two of the critical factors in the growth, proliferation, and metastasis of cancer cells and play a crucial role in inhibiting anti-cancer immune responses. Therefore, we used superparamagnetic iron oxide (SPION) nanoparticles (NPs) coated with thiolated chitosan (ChT) and trimethyl chitosan (TMC) and functionalized with hyaluronate (H) and TAT peptide for delivery of siRNA molecules against STAT3 and HIF-1α to cancer cells both in vivo and in vitro. The results indicated that tumor cell transfection with siRNA-encapsulated NPs robustly inhibited proliferation and migration and induced apoptosis in tumor cells. Furthermore, simultaneous silencing of HIF-1α and STAT3 significantly repressed cancer development in two different tumor types (4T1 breast cancer and CT26 colon cancer) which were associated with upregulation of cytotoxic T lymphocytes and IFN-γ secretion. The findings suggest inhibiting the HIF-1α/STAT3 axis by SPION-TMC-ChT-TAT-H NPs as an effective way to treat cancer.

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.

Optimization of chitosan-based polyelectrolyte nanoparticles for gene delivery, using design of experiment: in vitro and in vivo study

Gene therapy is a novel approach for cancer treatment and investigation for suitable gene delivery systems is remarkable. Here, preparation of a polyelectrolyte complex containing polysaccharides: trimethyl chitosan (TMC) as the positive and hyaluronate (HA), dextran sulfate and alginate as the negative part was studied. The optimized nanoparticles (TMC: between 0.2 and 0.47 mg/ml, HA: 0.35 mg/ml (≈131 nm, nearly full gene loading)) were obtained via primary screening followed by the D-optimal method. In vitro cellular study on the MCF7 cell line confirmed the non-toxicity and high cellular uptake (>90%) of prepared nanoparticles. Notably, in vivo study indicated noticeable tumor uptake of nanoparticles while low accumulation in vital organs such as heart, liver and lungs. Moreover, although a qualitative variable was considered, the applied method restricted the number of runs by selecting spots from the spherical atmosphere. The prepared nanoparticles could be suggested as an efficient and safe delivery system for cancer gene delivery.

New Frontiers in Molecular Imaging with Superparamagnetic Iron Oxide Nanoparticles (SPIONs): Efficacy, Toxicity, and Future Applications

Supermagnetic Iron Oxide Nanoparticles (SPIONs) are nanoparticles that have an iron oxide core and a functionalized shell. SPIONs have recently raised much interest in the scientific community, given their exciting potential diagnostic and theragnostic applications. The possibility to modify their surface and the characteristics of their core make SPIONs a specific contrast agent for magnetic resonance imaging but also an intriguing family of tracer for nuclear medicine. An example is 68Ga-radiolabeled bombesin-conjugated to superparamagnetic nanoparticles coated with trimethyl chitosan that is selective for the gastrin-releasing peptide receptors. These receptors are expressed by several human cancer cells such as breast and prostate neoplasia. Since the coating does not interfere with the properties of the molecules bounded to the shell, it has been proposed to link SPIONs with antibodies. SPIONs can be used also to monitor the biodistribution of mesenchymal stromal cells and take place in various applications. The aim of this review of literature is to analyze the diagnostic aspect of SPIONs in magnetic resonance imaging and in nuclear medicine, with a particular focus on sentinel lymph node applications. Moreover, it is taken into account the possible toxicity and the effects on human physiology to determine the SPIONs' safety.

Development of Ga-68 labeled, biotinylated thiosemicarbazone dextran-coated iron oxide nanoparticles as multimodal PET/MRI probe

Bifunctional biotinylated thiosemicarbazone dextran-coated iron oxide Nanoparticles (NPs) were fabricated. Aldehyde groups of the oxidized dextran-coating layer were utilized to conjugate biotin as a tumor-targeting agent and thiosemicarbazide as a cation chelator on the surface of NPs. The final product was characterized for physicochemical and biological properties. It was compatible with red blood cells and did not change the blood coagulation time. It also showed a significantly enhanced affinity to biotin receptor-positive 4T1 cells compared to non-biotinylated ones. The r2 relaxivity coefficient value of the final product was 110.2 mM^-1 s^-1. Although biotinylated NPs were easily radiolabeled with Ga-68 at room temperature, the stable radiolabeled NPs were achieved at a higher temperature (60 °C). The radiolabeled NPs were majorly accumulated in the liver and spleen. However, about 5.4% ID/g of the radiolabeled NPs was accumulated within the 4T1 tumor site. Blocking studies was performed by the biotin molecules pre-injection showed uptake reduction in the 4T1 tumor (about 1.1% ID/g). The radiolabeled NPs could be used for the early detection of biotin receptor-positive tumors via PET-MRI.

A new molecular probe: An NRP-1 targeting probe for the grading diagnosis of glioma in nude mice

Magnetic resonance molecular imaging, as a safe imaging technology, provides a new idea for the early qualitative and hierarchical diagnosis of gliomas. The purpose of this study was to design and evaluate the value of neuropilin-1 (NRP-1) targeting molecular probes in the hierarchical diagnosis of gliomas. First, we created an NRP-1 targeted magnetic resonance molecular probe (USPIO-PEG-tLyP-1) by combining the polypeptide tLyP-1 with ultra-small superparamagnetic iron oxide nanoparticles (USPIONs), detecting the physical properties by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Second, in vivo experiments, we established two different degrees of malignant gliomas in-situ in nude mice by injecting U87 and CHG-5 cells. Then, to detect the binding ability of the probe with different grades of tumour tissues, we injected the probe into the tumour-bearing mice through the tail vein. Next, MRI was performed before injection, and 6 h, 12 h, 24 h after injection, and we found significantly more iron particles in the tumour tissues of U87 tumour-bearing mice than in tumour tissues of CHG-5 tumour-bearing mice. The signal intensities of the T2-weighted images of the tumour tissues of each group as well as microscopic observations by Prussian blue staining indicated that the binding ability of this molecular probe to U87 glioma (HGG) with high NRP-1 expression was significantly greater than that of CHG-5 glioma (LGG) with low NRP-1 expression (P < 0.01). Therefore, this study confirms that the novel molecular probe USPIO-PEG-tLyP-1 can be used for the grading diagnosis by MRI for gliomas of high and low grade with different NRP-1 expression levels.

Novel insights into breast cancer progression and metastasis: A multidisciplinary opportunity to transition from biology to clinical oncology

According to the most recent epidemiological studies, breast cancer shows the highest incidence and the second leading cause of death in women. Cancer progression and metastasis are the main events related to poor survival of breast cancer patients. This can be explained by the presence of highly resistant to chemo- and radiotherapy stem cells in many breast tumor tissues. In this context, numerous studies highlighted the possible involvement of epithelial to mesenchymal transition phenomenon as biological program to generate cancer stem cells, and thus participate to both metastatic and drug resistance process. Therefore, the comprehension of mechanisms (both cellular and molecular) involved in breast cancer occurrence and progression can lay the foundation for the development of new diagnostic and therapeutical protocols. In this review, we reported the most important findings in the field of breast cancer highlighting the most recent data concerning breast tumor biology, diagnosis and therapy.