Radiolabeled theranostics: magnetic and gold nanoparticles

Anti-CD64 Antibody-Conjugated PLGA Nanoparticles Containing Methotrexate and Gold for Theranostics Application in Rheumatoid Arthritis

Rheumatoid arthritis, an autoimmune disorder, exerts a considerable effect on quality of life. The inflammatory mechanism involved in rheumatoid arthritis is not clearly known, and therefore the need to develop effective medicines as well as new methods for early detection is a challenge. In this study, we developed PLGA nanoparticles containing gold and methotrexate in core and anti-CD64 antibody conjugated to nanoparticle surface via coupling process. The nanoparticles were examined for their surface morphology using SEM and TEM. The mean particle size, zeta potential, and PDI values of nanoparticles were 413.6 ± 2.89 nm, -10.12 ± 2.12 mV, and 0.23 ± 0.04, respectively, indicating good stability and particle homogeneity. In vitro drug release revealed a controlled release pattern with 93.44 ± 1.60% up to 72 h of release in the presence of pH 5.8, indicating the influence of pH and NIR on drug release. In vivo results on adjuvant-induced arthritis on Wistar rats indicated that animals receiving antibody-conjugated nanoparticles showed improvement in clinical indices and arthritic score as compared to non-conjugated nanoparticles and free drugs. This innovative drug delivery system will be an excellent strategy to maximize therapeutic effectiveness by limiting dosage-related side effects.

Gold Nanobipyramids for Near-Infrared Fluorescence-Enhanced Imaging and Treatment of Triple-Negative Breast Cancer

There is an imminent need for novel strategies for the diagnosis and treatment of aggressive triple-negative breast cancer (TNBC). Cell-targeted multifunctional nanomaterials hold great potential, as they can combine precise early-stage diagnosis with local therapeutic delivery to specific cell types. In this study, we used mesoporous silica (MS)-coated gold nanobipyramids (MS-AuNBPs) for fluorescence imaging in the near-infrared (NIR) biological window, along with targeted TNBC treatment. Our MS-AuNBPs, acting partly as light amplification components, allow considerable metal-enhanced fluorescence for a NIR dye conjugated to their surfaces compared to the free dye. Fluorescence analysis confirms a significant increase in the dye's modified quantum yield, indicating that MS-AuNBPs can considerably increase the brightness of low-quantum-yield NIR dyes. Meanwhile, we tested the chemotherapeutic efficacy of MS-AuNBPs in TNBC following the loading of doxorubicin within the MS pores and functionalization to target folate receptor alpha (FRα)-positive cells. We show that functionalized particles target FRα-positive cells with significant specificity and have a higher potency than free doxorubicin. Finally, we demonstrate that FRα-targeted particles induce stronger antitumor effects and prolong overall survival compared to the clinically applied non-targeted nanotherapy, Doxil. Together with their excellent biocompatibility measured in vitro, this study shows that MS-AuNBPs are promising tools to detect and treat TNBCs.

Radiolabelled Extracellular Vesicles as Imaging Modalities for Precise Targeted Drug Delivery

Extracellular vesicles (ECVs) have been abandoned as bio-inspired drug delivery systems (DDS) in the biomedical field. ECVs have a natural ability to cross over extracellular and intracellular barriers, making them superior to manufactured nanoparticles. Additionally, they have the ability to move beneficial biomolecules among far-flung bodily cells. These advantages and the accomplishment of favorable in vivo results convincingly show the value of ECVs in medication delivery. The usage of ECVs is constantly being improved, as it might be difficult to develop a consistent biochemical strategy that is in line with their useful clinical therapeutic uses. Extracellular vesicles (ECVs) have the potential to enhance the therapy of diseases. Imaging technologies, particularly radiolabelled imaging, have been exploited for non-invasive tracking to better understand their in vivo activity.

Nanoparticles labeled with gamma-emitting radioisotopes: an attractive approach for in vivo tracking using SPECT imaging

Providing accurate molecular imaging of the body and biological process is critical for diagnosing disease and personalizing treatment with the minimum side effects. Recently, diagnostic radiopharmaceuticals have gained more attention in precise molecular imaging due to their high sensitivity and appropriate tissue penetration depth. The fate of these radiopharmaceuticals throughout the body can be traced using nuclear imaging systems, including single-photon emission computed tomography (SPECT) and positron emission tomography (PET) modalities. In this regard, nanoparticles are attractive platforms for delivering radionuclides into targets because they can directly interfere with the cell membranes and subcellular organelles. Moreover, applying radiolabeled nanomaterials can decrease their toxicity concerns because radiopharmaceuticals are usually administrated at low doses. Therefore, incorporating gamma-emitting radionuclides into nanomaterials can provide imaging probes with valuable additional properties compared to the other carriers. Herein, we aim to review (1) the gamma-emitting radionuclides used for labeling different nanomaterials, (2) the approaches and conditions adopted for their radiolabeling, and (3) their application. This study can help researchers to compare different radiolabeling methods in terms of stability and efficiency and choose the best way for each nanosystem.

Preparation and characterization of a gemini surfactant-based biomimetic complex for gene delivery

Gemini surfactants (GS) have been explored as non-viral gene delivery systems. Nevertheless, their cytotoxicity and the limitations in the in vivo studies have impeded their development. To attenuate toxicity and further explore their possibilities in gene delivery, a series of GS (18-7-18)-based gene delivery systems complexed with red blood cell membranes (RBCM) or/and DOPE-PEG₂₀₀₀ (DP) were prepared and evaluated. EGFP-encoding plasmids were delivered via GS-based complexes and the efficiency of gene transfection was evaluated by imaging of the major organs after intravenous administration in mice and qPCR quantification in hepatocytes. In order to assess the safety of GS-based complexes, the hemolysis test, serum biochemical indices, H&E staining and CCK-8 test were examined. The results revealed that EGFP was primarily expressed in livers, and all complexes showed minimal acute toxicity to major organs. Moreover, we found that the dual incorporation of RBCM and DP could significantly elevate the transfection efficiency and cell viability in hepatocytes. Overall, the results indicated that GS-based complexes possessed great potential as vectors for gene delivery both in vivo and in vitro and the dual incorporation of RBCM and DP could be a promising gene delivery approach with high transfection efficacy and low toxicity.

Preliminary Evaluation of Iron Oxide Nanoparticles Radiolabeled with 68Ga and 177Lu as Potential Theranostic Agents

Theranostic radioisotope pairs such as Gallium-68 (⁶⁸Ga) for Positron Emission Tomography (PET) and Lutetium-177 (¹⁷⁷Lu) for radioisotopic therapy, in conjunction with nanoparticles (NPs), are an emerging field in the treatment of cancer. The present work aims to demonstrate the ability of condensed colloidal nanocrystal clusters (co-CNCs) comprised of iron oxide nanoparticles, coated with alginic acid (MA) and stabilized by a layer of polyethylene glycol (MAPEG) to be directly radiolabeled with ⁶⁸Ga and its therapeutic analog ¹⁷⁷Lu. ⁶⁸Ga/¹⁷⁷Lu- MA and MAPEG were investigated for their in vitro stability. The biocompatibility of the non-radiolabeled nanoparticles, as well as the cytotoxicity of MA, MAPEG, and [¹⁷⁷Lu]Lu-MAPEG were assessed on 4T1 cells. Finally, the ex vivo biodistribution of the ⁶⁸Ga-labeled NPs as well as [¹⁷⁷Lu]Lu-MAPEG was investigated in normal mice. Radiolabeling with both radioisotopes took place via a simple and direct labelling method without further purification. Hemocompatibility was verified for both NPs, while MTT studies demonstrated the non-cytotoxic profile of the nanocarriers and the dose-dependent toxicity for [¹⁷⁷Lu]Lu-MAPEG. The radiolabeled nanoparticles mainly accumulated in RES organs. Based on our preliminary results, we conclude that MAPEG could be further investigated as a theranostic agent for PET diagnosis and therapy of cancer.

Synthesis and in vitro proof-of-concept studies on bispecific iron oxide magnetic nanoparticles targeting PSMA and GRP receptors for PET/MR imaging of prostate cancer

Prostate cancer (PCa) is the most common malignancy worldwide in men. This is a proof-of-concept study describing the development of ⁶⁸Ga-magnetic iron oxide nanoparticles (mNP) targeting prostate specific membrane antigen (PSMA) and gastrin releasing peptide (GRPR) receptors as potential tools for diagnosis of PCa with PET/MRI. Two pharmacophores targeting PSMA, 1, and GRPR, 2, were coupled to mNPs carrying -SH (mNP-S1/2) or -NH₂ (mNP-N1/2) groups. The mNP-S1/2 and mNP-N1/2 were characterized for their size, zeta potential, structure, and efficiency of functionalization using dynamic light scattering (DLS), FT-IR and RP-HPLC. A direct ⁶⁸Ga-labelling procedure was followed, where ⁶⁸Ga-mNP-N1/2 proved superior to ⁶⁸Ga-mNP-S1/2 regarding radiolabelling efficiency, and thus were further evaluated in vitro. Toxicity studies in PCa cells (LNCaP, PC-3) showed low toxicity, and minimal hemolysis of red blood cells. In vitro assays in cells expressing PSMA (LNCaP), and GRPR (PC-3), showed specific time-dependent binding (40 min to plateau), high avidity (PC-3: K_d = 28.27 nM, LNCaP: K_d = 11.49 nM) and high internalization rates for ⁶⁸Ga-mNP-N1/2 in both cell lines.

Transforming Nuclear Medicine with Nanoradiopharmaceuticals

Nuclear medicine is expected to make major advances in cancer diagnosis and therapy; tumor-targeted radiopharmaceuticals preferentially eradicate tumors while causing minimal damage to healthy tissues. The current scope of nuclear medicine can be significantly expanded by integration with nanomedicine, which utilizes nanoparticles for cancer diagnosis and therapy by capitalizing on the increased surface area-to-volume ratio, the passive/active targeting ability and high loading capacity, the greater interaction cross section with biological tissues, the rich surface properties of nanomaterials, the facile decoration of nanomaterials with a plethora of functionalities, and the potential for multiplexing several functionalities within one construct. This review provides a comprehensive discussion of nuclear nanomedicine using tumor-targeted nanoparticles for cancer radiation therapy with either pre-embedded radionuclides or nonradioactive materials which can be extrinsically triggered using various external nuclear particle sources to produce in situ radioactivity. In addition, it describes the prospect of combining nuclear nanomedicine with other modalities to enable synergistically enhanced combination therapies. The review also discusses advances in the fabrication of radionuclides as well as describes laser ablation technologies for producing nanoradiopharmaceuticals, which combine the ease of production with exceptional purity and rapid biodegradability, along with additional imaging or therapeutic functionalities. From a practical standpoint, these attributes of nanoradiopharmaceuticals may provide distinct advantages in diagnostic/therapeutic sensitivity and specificity, imaging resolution, and scalability of turnkey platforms. Coupling image-guided targeted radiation therapy with the possibility of in situ activation of nanomaterials as well as combining with other therapeutic modalities using a multifunctional nanoplatform could herald an era of exciting technological and therapeutic advances to radically transform the landscape of nuclear medicine. The review concludes with a discussion of current challenges and presents the authors' views on future opportunities to stimulate further research in this rewarding field of high societal impact.

Recent Advances of Magnetic Gold Hybrids and Nanocomposites, and Their Potential Biological Applications

Magnetic gold nanoparticles (mGNP) have become a great interest of research for nanomaterial scientists because of their significant magnetic and plasmonic properties applicable in biomedical applications. Various synthetic approaches and surface modification techniques have been used for mGNP including the most common being the coprecipitation, thermal decomposition, and microemulsion methods in addition to the Brust Schiffrin technique, which involves the reduction of metal precursors in a two-phase system (water and toluene) in the presence of alkanethiol. The hybrid magnetic–plasmonic nanoparticles based on iron core and gold shell are being considered as potential theranostic agents. In this critical review, in addition to future works, we have summarized recent developments for synthesis and surface modification of mGNP with their applications in modern biomedical science such as drug and gene delivery, bioimaging, biosensing, and neuro-regeneration, neuro-degenerative and arthritic disorders. This review includes techniques and biological applications of mGNP majorly based on research from the previous six years.

Stimuli-responsive graphene oxide and methotrexate-loaded magnetic nanoparticles for breast cancer-targeted therapy

Aim: Nanocomposites of graphene oxide (GO) loaded with PEGylated superparamagnetic iron oxide nanoparticles and grafted with methotrexate and stimuli-responsive linkers (GO-SPION-MTX) were developed for photothermal and chemotherapy of breast cancer. Methods: PEGylated SPIONs were synthesized and conjugated with chemotherapeutic targeting agent MTX, which were then loaded on GO to prepare GO-SPION-MTX nanocomposites. To evaluate the photothermal effect of the nanocomposites, they were examined in breast cancer cell lines with low doses of near-infrared (NIR) laser radiation with/without acetazolamide. Results: The GO-SPION-MTX nanocomposites were found to be internalized by the folate-receptor-positive cancer cells and induce high cytotoxicity on exposure to NIR laser rays. Conclusion: Our findings suggest that the GO-SPION-MTX nanocomposite can potentially be used as a multimodal nanomedicine/theranostic against breast cancer.

Heterodimers of metal nanoparticles: synthesis, properties, and biological applications

Heterodimers of metal nanoparticles consist of two metals, come in many sizes and adopt various shapes. They offer unique properties due to the presence of two metals and have the extraordinary flexibility needed to serve as a multipurpose platform for diverse applications in areas including photonics, sensing, and catalysis. Heterodimer nanoparticles contain different metals that contribute to extraordinary surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS), and catalytic properties. These properties make them versatile molecules that can be used in intracellular imaging, as antibacterial agents, as photocatalytic and biological macromolecules and for the detection of chemical substances. Moreover, heterodimer nanoparticles are composed of the two metals within larger molecules that provide more choices for modification and application. In this review, we briefly summarize the lesser-known aspects of heterodimers, including some of their properties, and present concrete examples of recent progress in synthesis and applications. This review provides a perspective on achievements and suggests a framework for future research with a focus on the synthesis and application of heterodimers. We also explore the possible applications of heterodimer nanoparticles based on their unique properties.

Synthesis and In Vitro Evaluation of Gold Nanoparticles Functionalized with Thiol Ligands for Robust Radiolabeling with 99mTc

Radiolabeled gold nanoparticles (AuNPs) have been widely used for cancer diagnosis and therapy over recent decades. In this study, we focused on the development and in vitro evaluation of four new Au nanoconjugates radiolabeled with technetium-99m (99mTc) via thiol-bearing ligands attached to the NP surface. More specifically, AuNPs of two different sizes (2 nm and 20 nm, referred to as Au(2) and Au(20), respectively) were functionalized with two bifunctional thiol ligands (referred to as L1H and L2H). The shape, size, and morphology of both bare and ligand-bearing AuNPs were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. In vitro cytotoxicity was assessed in 4T1 murine mammary cancer cells. The AuNPs were successfully radiolabeled with 99mTc-carbonyls at high radiochemical purity (>95%) and showed excellent in vitro stability in competition studies with cysteine and histidine. Moreover, lipophilicity studies were performed in order to determine the lipophilicity of the radiolabeled conjugates, while a hemolysis assay was performed to investigate the biocompatibility of the bare and functionalized AuNPs. We have shown that the functionalized AuNPs developed in this study lead to stable radiolabeled nanoconstructs with the potential to be applied in multimodality imaging or for in vivo tracking of drug-carrying AuNPs.

Radioactive Gold Nanoparticle in Two Forms (¹⁹⁸₇₉Au GNPs and ^99mTc-GNPs) for Lung Cancer Antiproliferative Induction and Intralesional Imaging: A Proof of Concept

BACKGROUND

Lung cancer is among the most common cancers worldwide, responsible for 13% of all new cancer cases. Also, it is the leading cause of cancer death among both men and women. In this scenario, an effective and efficient treatment is required.

OBJECTIVE

Production of two gold nanoparticles: 198Au and 99mTc-Au. The first one has been produced from irradiation of the 197Au in order to produce a beta-emitter gold nanoparticle for cancer therapy. The second one has been produced from the radiolabeling of gold nanoparticles with technetium 99 metastable in order to produce imaging nanoagent.

METHODS

The 198Au nanoparticles were produced by irradiation and identified by hyper-purity germanium (HPGe). They were then evaluated in vitro in order to confirm the behavior on cell proliferation of lung cancer cell lines by the MTT methodology using A549 cells. The 99mTc-Au nanoparticles were produced by directradiolabeling with 99mTc and evaluated in vivo as intralesional nanoagent.

RESULTS

The results showed that in both cases, all the nanoparticles have performed their duties with excellence. The 198Au nanoparticles were capable to kill lung cancer cells, while 99mTc-Au was capable to image the tumor after intralesional injection. In addition, 99mTc-Au nanoparticles were useful for biodistribution assay imaging, showing the main organs responsible for the nanoparticle uptake in healthy animals.

CONCLUSION

Both gold nanoparticles showed to be a highly efficient nanoagent for both: therapy and diagnosing of lung cancer.

Amelioration of Tumor Targeting and In Vivo Biodistribution of 99mTc-Methotrexate-Gold Nanoparticles (99mTc-Mex-AuNPs)

Gold nanoparticles (AuNPs) represent very attractive and promising drug delivery carriers due to their unique dimensions, adjustable surface functions, and controllable drug release. Therefore, AuNPs are used to overcome the limitations of conventional chemotherapy, for example methotrexate (Mex), one of the first-generation chemotherapy drugs for cancer treatment, whose usefulness has been restricted due to drug resistance and dose-dependent side effects. In the present study, the AuNPs drug delivery system was synthesized and loaded with technetium-99 m radiolabeled Methotrexate (^99mTc-Mex) to produce new potential nanoradiopharmaceutical for tumor targeting and further imaging. The Methotrexate loaded gold nanoparticles (Mex-AuNPs) successfully prepared in small spherical particle size (20.3 nm), polydispersity index PDI (< 0.5) and a zeta potential (-17.6 mV) with loading efficiency% (93 ± 1.2%) of methotrexate at 30 min as an optimum stirring time and showed strong absorption peak for Mex-AuNPs at λ_max, 525 nm. The in vitro release profile of Mex-AuNPs showed high release percent of methotrexate at pH 5; the Q_0.5 h and Q_8h were 21.2 ± 1.5% and 92.9 ± 3.4%, respectively. The in vitro cytotoxicity was investigated at different concentrations (0.024-50 μl/100 μl) of Mex-AuNPs (1 mg/ml) against MCF-7 (Michigan Cancer Foundation-7) breast cancer cells by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay technique. Mex-AuNPs showed higher anticancer activity with low inhibitory concentration (IC₅₀ = 0.098 μl/100 μl) that was three times lower than the inhibitory concentration (IC₅₀) of methotrexate (IC₅₀ = 0.3 μl/100 μl). ^99mTc-Mex complex prepared by direct reduction method at maximum radiochemical yield (RCY)% ̴ 98.3 ± 1.09 % was loaded in AuNPs to form ^99mTc-Mex-AuNPs with loading efficiency% (93 ± 1.2 %) at 30 min of stirring time. ^99mTc-Mex-AuNPs showed convenient in vitro stability in mice serum up to 24 h with RCY% > 90 %. The preclinical biodistribution studies of ^99mTc-Mex-AuNPs were performed in 3 experimental groups A (intravenous (I.V.) injected normal mice), B and C (I.V. and intratumor (I.T.) injected tumor bearing mice, respectively). The ^99mTc-Mex-AuNPs achieved highest tumor uptake (93 ± 0.39 %ID/g) and highest Target/NonTarget (T/NT) ratio (58.1 ± 0.91) with high Tumor/Blood (T/B) ratio (25.8 ± 0.11) at 10 min post I.T. injection and retained high tumor uptake (79 ± 0.65 %ID/g) up to 60 min post I.T. injection before escaping into blood stream. Consequently, ^99mTc-Mex-AuNPs can be considered as new potential nanoradiopharmaceutical in tumor diagnosis.

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.

Radiolabeling strategies and pharmacokinetic studies for metal based nanotheranostics

Radiolabeled metal-based nanoparticles (MNPs) have drawn considerable attention in the fields of nuclear medicine and molecular imaging, drug delivery, and radiation therapy, given the fact that they can be potentially used as diagnostic imaging and/or therapeutic agents, or even as theranostic combinations. Here, we present a systematic review on recent advances in the design and synthesis of MNPs with major focuses on their radiolabeling strategies and the determinants of their in vivo pharmacokinetics, and together how their intended applications would be impacted. For clarification, we categorize all reported radiolabeling strategies for MNPs into indirect and direct approaches. While indirect labeling simply refers to the use of bifunctional chelators or prosthetic groups conjugated to MNPs for post-synthesis labeling with radionuclides, we found that many practical direct labeling methodologies have been developed to incorporate radionuclides into the MNP core without using extra reagents, including chemisorption, radiochemical doping, hadronic bombardment, encapsulation, and isotope or cation exchange. From the perspective of practical use, a few relevant examples are presented and discussed in terms of their pros and cons. We further reviewed the determinants of in vivo pharmacokinetic parameters of MNPs, including factors influencing their in vivo absorption, distribution, metabolism, and elimination, and discussed the challenges and opportunities in the development of radiolabeled MNPs for in vivo biomedical applications. Taken together, we believe the cumulative advancement summarized in this review would provide a general guidance in the field for design and synthesis of radiolabeled MNPs towards practical realization of their much desired theranostic capabilities. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > Diagnostic Nanodevices Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Radiolabeled liposomes and lipoproteins as lipidic nanoparticles for imaging and therapy

Radiolabeled lipidic nanoparticles, particularly liposomes and lipoproteins, are of great interest as agents for imaging and therapy, due not only to their peculiar physicochemical and biological properties, but also to their great versatility and the ability to manipulate them to obtain the desired properties. This review provides an overview of radionuclide labeling strategies for preparing diagnostic and therapeutic nanoparticles based on liposomes and lipoproteins that have been developed to date, as well as the main quality control methods and in vivo applications.

Recent advances in the development of nanoparticles for multimodality imaging and therapy of cancer

This review explores recent work directed toward the development of nanoparticles (NPs) for multimodality cancer imaging and targeted cancer therapy. In the growing era of precision medicine, theranostics, or the combined use of targeted molecular probes in diagnosing and treating diseases is playing a particularly powerful role. There is a growing interest, particularly over the past few decades, in the use of NPs as theranostic tools due to their excellent performance in receptor target specificity and reduction in off-target effects when used as therapeutic agents. This review discusses recent advances, as well as the advantages and challenges of the application of NPs in cancer imaging and therapy.

Gold Nanoparticles and Nanorods in Nuclear Medicine: A Mini Review

In the last decade, many innovative nanodrugs have been developed, as well as many nanoradiocompounds that show amazing features in nuclear imaging and/or radiometabolic therapy. Their potential uses offer a wide range of possibilities. It can be possible to develop nondimensional systems of existing radiopharmaceuticals or build engineered systems that combine a nanoparticle with the radiopharmaceutical, a tracer, and a target molecule, and still develop selective nanodetection systems. This review focuses on recent advances regarding the use of gold nanoparticles and nanorods in nuclear medicine. The up-to-date advancements will be shown concerning preparations with special attention on the dimensions and functionalizations that are most used to attain an enhanced performance of gold engineered nanomaterials. Many ideas are offered regarding recent in vitro and in vivo studies. Finally, the recent clinical trials and applications are discussed.

Targeted delivery of doxorubicin by magnetic mesoporous silica nanoparticles armed with mucin-1 aptamer

Distinctive physicochemical features make mesoporous silica magnetic nanoparticles (SPION@SiO₂) as a multifunctional nanosystem (NS) for the targeted delivery of therapeutic agents. In the present study, we engineered the mucin-1 (MUC-1) conjugated SPION@SiO₂ (SPION@SiO₂-MUC-1) for the targeted delivery of doxorubicin (DOX) to the breast cancer cells. Superparamagnetic iron oxide nanoparticles (SPIONs) were synthesised using thermal decomposition technique, and then, coated with mesoporous silica to modify their biocompatibility and reduce undesired cytotoxic effects. Subsequently, DOX was loaded onto the silica porous structures, which was then nanoparticles (NPs) grafted with 5'-amine-modified MUC-1 aptamers. Transmission electron microscopy and particle size analysis by differential light scattering exhibited spherical and monodisperse NPs with a size range of 5-27 nm. The FT-IR spectroscopy confirmed the surface modification of the engineered NS. The surface area and pore size of the SPION@SiO₂-COOH NSs were calculated by BJH and BET calculations. The MTT assay revealed higher cytotoxicity of MUC-1 grafted SPION@SiO₂ NSs in the MUC-1-positive MCF-7 cells as compared to the control MUC-1-negative MDA-MB-231 cells. The flow cytometry analysis of the SPION@SiO₂-MUC-1 NSs revealed a higher uptake as compared to the non-targeted nanocomposite (NC) in MCF-7 cells. In conclusion, the engineered SPION@SiO₂-MUC-1 NS is proposed to serve as an effective multifunctional targeted nanomedicine/theranostics against MUC-1 overexpressing cancer cells.

Set of Highly Stable Amine- and Carboxylate-Terminated Dendronized Au Nanoparticles with Dense Coating and Nontoxic Mixed-Dendronized Form

The synthesis of a novel poly(propyleneimine) (PPI) dendron in gram scale as well as its use in the formation of a highly stable, dendronized gold nanoparticle (AuNP)-based drug delivery platform is described herein. The AuNP-based platform is composed of three complementary parts: (i) a 15 nm AuNP core, (ii) a heterofunctional thioctic acid-terminated tetraethylene glycol spacer, and (iii) a third-generation PPI dendron with a unique protonation profile and diverse end-group functionalization that allows for further derivatization. The prepared dendronized AuNPs are able to withstand several rounds of lyophilization cycles with no sign of aggregation, are stable in phosphate-buffered saline and Hanks' buffer as well as in serum, and are resistant to degradation by glutathione exchange reactions. This nanocarrier platform displays a dense coating, with >1400 dendrons/AuNPs, which will enable very high payload. Furthermore, while amine-terminated AuNPs expectedly showed cytotoxicity against the MCF-7 breast cancer cell line from a NP concentration of 1 nM, the mixed monolayer AuNPs (coated with 40/60 amine/carboxylate dendrons) interestingly did not exhibit any sign of toxicity at concentrations as high as 15 nM, similar to the carboxylate-terminated AuNPs. The described dendronized AuNPs address the current practical need for a stable NP-based drug delivery platform which is scalable and easily conjugable, has long-term stability in solution, and can be conveniently formulated as a powder and redispersed in desired buffer or serum.

Magnetic-Plasmonic Heterodimer Nanoparticles: Designing Contemporarily Features for Emerging Biomedical Diagnosis and Treatments

Magnetic-plasmonic heterodimer nanostructures synergistically present excellent magnetic and plasmonic characteristics in a unique platform as a multipurpose medium for recently invented biomedical applications, such as magnetic hyperthermia, photothermal therapy, drug delivery, bioimaging, and biosensing. In this review, we briefly outline the less-known aspects of heterodimers, including electronic composition, interfacial morphology, critical properties, and present concrete examples of recent progress in synthesis and applications. With a focus on emerging features and performance of heterodimers in biomedical applications, this review provides a comprehensive perspective of novel achievements and suggests a fruitful framework for future research.

The analysis of 2,3-dicarboxypropane-1,1-diphosphonic acid-coated magnetite nanoparticles under an external magnetic field and their radiolabeling for possible theranostic applications

The advances in nanotechnology are directed towards the development of new theranostic agents based on magnetic nanoparticles that can be used for both cancer detection and treatment.

Emerging vistas in theranostic medicine

Recent years have witnessed a paradigm shift in the focus of healthcare towards development of customized therapies which cater to the unmet needs in a myriad of disease areas such as cancer, infections, cardiovascular diseases, neurodegenerative disorders and inflammatory disorders. The term 'theranostic' refers to such multifunctional systems which combine the features of diagnosis and treatment in a single platform for superior control of the disease. Theranostic systems enable detection of disease, treatment and real time monitoring of the diseased tissue. Theranostic nanocarriers endowed with multiple features of imaging, targeting, and providing on-demand delivery of therapeutic agents have been designed for enhancement of therapeutic outcomes. Fabrication of theranostics involves utilization of materials having distinct properties for imaging, targeting, and programming drug release spatially and temporally. Although the field of theranostics has been widely researched and explored so far for treatment of different types of cancer, there have been considerable efforts in the past few years to extend its scope to other areas such as infections, neurodegenerative disorders and cardiovascular diseases. This review showcases the potential applications of theranostics in disease areas other than cancer. It also highlights the cardinal issues which need to be addressed for successful clinical translation of these theranostic tools.

Synthesis of metallic nanoparticles by microplasma

The synthesis of metallic nanoparticles has been of long standing interest, primarily induced by their novel and unique properties that differ considerably from bulk materials. Despite various methods have been developed, it is still a challenge to produce high-quality metallic nanoparticles with controllable properties in a simple, cost-effective and environmentally benign manner. However, the development of the microplasma-assisted technology can bring an answer to this formidable challenge. In the present work, four main microplasma configurations used for metallic synthesis of metallic nanoparticles are reviewed.  These are  hollow-electrode microdischarges, microplasma jets with external electrodes, microplasma jets with consumable electrodes and plasma–liquid systems. The state of the art characterization methodologies and diagnostic techniques for in situ microplasma-assisted precursor dissociation as well as ex situ metallic nanoparticles analysis is also summarized. Further, a broad category of representative examples of microplasma-induced metallic nanoparticle fabrication is presented, together with the discussion of possible synthesis mechanisms. This is followed by a brief introduction to related safety considerations. Finally, the future perspectives, associated challenges and feasible solutions for scale-up of this technique are pointed out.

Graphical Abstract:

Evaluation of theranostic perspective of gold-silica nanoshell for cancer nano-medicine: a numerical parametric study

Using gold-silica nanoshell as a reference nano-agent, this work has performed preliminary numerical parametric study to investigate the feasibility and if feasible the efficiency of using a single nano-agent to achieve theranostic goals. In total, seven generics of gold-silica nanoshells have been tested including the R[50,10] (radius of the silica core is 50 nm and thickness of the gold shell is 10 nm), R[40,15], R[55,25], R[40,40], R[75,40], R[104,23], and R[154,24] nanoshells. A planar tissue model has been constructed as the platform for parametric study. For mathematical modeling, radiant transport equation (RTE) has been applied to describe the interactions among laser lights, the hosting tissue, and the hosted nanoshells and Penne's bio-heat equation has been applied to describe the hyperthermia induced by such interactions. Effects of different nanoshell generics on the diffuse reflectance signal and hyperthermia temperature transition have been simulated, basing on which the potential of a certain nanoshell generic as theranostic nano-agent has been evaluated. It has been found that it is highly feasible for gold-silica nanoshells to be engineered for theranostic purpose and nanoshell generics that are preferentially scattering should be explored for good theranostic candidates. On the condition that nanoshell generic with the right optical properties has been located, a moderate nanoshell retention in the target tissue site is already sufficient to induce effective theranostic effects, which indicates that theranostic nano-medicine might not have a stringent requirement for the delivery technique. Among nanoshells that have been tested, the R[55,25] nanoshell seems to be a promising candidate as theranostic nano-agent. Further testing on it is highly recommended. Nanoshells that are preferentially absorbing such as the R[50,10] and R[40,15] nanoshells are efficient photothermal agent and could be used for therapeutic purpose only. However, it is not recommended that preferentially absorbing nanoshells being used for theranostic purpose due to possible negative effects such nanoshells might bring to the diffuse reflectance signal.

Ultra-sensitive detection by metal nanoparticles-mediated enhanced SPR biosensors

Surface plasmon resonance (SPR), as an optical technique, has widely been used for the detection of biomarkers. Various investigations have been conducted to address the impacts of SPR on the kinetics of biological interactions between the ligand and its cognate bio-element. Up until now, different biofunctionalized metal nanoparticles (NPs) have been used for the ultrasensitive detection of biomarkers in the enhanced SPR. The enhancement of plasmonic properties and refractive index by means of metal NPs in SPR-based biosensors have significantly improved the diagnosis and monitoring of molecular markers in different disesaes including malignancies. In all the enhanced SPR systems utilized for the direct/sandwich assay, each NP is covalently modified with the analyte molecules like antibody (Ab) or a nucleic acid such as DNA/RNA aptamer (Ap) capable of interaction with the related biomarker(s). The increasing of density near the gold surface and plasmonic coupling of gold film and NPs can provide a large shift in the refractive index enhancing the plasmonic resonance because the SPR response unit is sensitive to alteration of the refractive index and the mass shifting onto the chip surface. In this study, we review the potential applications of two major NPs for enhancing the SPR signals for the detection of molecular biomarkers, including gold and magnetic NPs.

Enzyme replacement therapies: what is the best option?

Despite many beneficial outcomes of the conventional enzyme replacement therapy (ERT), several limitations such as the high-cost of the treatment and various inadvertent side effects including the occurrence of an immunological response against the infused enzyme and development of resistance to enzymes persist. These issues may limit the desired therapeutic outcomes of a majority of the lysosomal storage diseases (LSDs). Furthermore, the biodistribution of the recombinant enzymes into the target cells within the central nervous system (CNS), bone, cartilage, cornea, and heart still remain unresolved. All these shortcomings necessitate the development of more effective diagnosis and treatment modalities against LSDs. Taken all, maximizing the therapeutic response with minimal undesired side effects might be attainable by the development of targeted enzyme delivery systems (EDSs) as a promising alternative to the LSDs treatments, including different types of mucopolysaccharidoses ( MPSs ) as well as Fabry, Krabbe, Gaucher and Pompe diseases.

Mucin-1 aptamer-armed superparamagnetic iron oxide nanoparticles for targeted delivery of doxorubicin to breast cancer cells

Introduction: Superparamagnetic iron oxide nanoparticles (SPIONs) can be functionalized with various agents (e.g., targeting and therapeutic agents) and used for targeted imaging/therapy of cancer. In the present study, we engineered doxorubicin (DOX)-conjugated anti-mucin -1 (MUC-1) aptamer (Ap)-armed PEGylated SPIONs for targeted delivery of DOX molecules to the breast cancer MCF-7 cells. Methods: The SPIONs were synthesized using the thermal decomposition method and modified by polyethylene glycol (PEG) to maximize their biocompatibility and minimize any undesired cytotoxicity effects. Subsequently, DOX molecules were loaded onto the SPIONs, which were further armed with amine-modified MUC-1 aptamer by EDC/NHS chemistry. Results: The morphologic and size analyses of nanoparticles (NPs) by transmission electron microscopy (TEM) and dynamic light scattering (DLS) revealed spherical and monodisperse MNPs with a size range of 5-64 nm. The FT-IR spectrophotometry and 1 HNMR analysis confirmed the surface modification of NPs. The cytotoxicity assay of the aptamer-armed MNPs exhibited a higher death rate in the MUC-1 over-expressing MCF-7 cells as compared to the MUC-1 under-expressing MDA-MB-231 cells. The flow cytometry analysis of the engineered Ap-armed SPIONs revealed a higher uptake as compared to the SPIONs alone. Conclusion: Based on our findings, the anti-MUC-1 Ap-armed PEGylated SPIONs loaded with DOX molecules could serve as an effective multifunctional theranostics for simultaneous detection and eradication of MUC-1-positive breast cancer cells.

Recent advances in aptamer-armed multimodal theranostic nanosystems for imaging and targeted therapy of cancer

The side effects of chemotherapeutics during the course of cancer treatment limit their clinical outcomes. The most important mission of the modern cancer therapy modalities is the delivery of anticancer drugs specifically to the target cells/tissue in order to avoid/reduce any inadvertent non-specific impacts on the healthy normal cells. Nanocarriers decorated with a designated targeting ligand such as aptamers (Aps) and antibodies (Abs) are able to deliver cargo molecules to the target cells/tissue without affecting other neighboring cells, resulting in an improved treatment of cancer. For targeted therapy of cancer, different ligands (e.g., protein, peptide, Abs, Aps and small molecules) have widely been used in the development of different targeting drug delivery systems (DDSs). Of these homing agents, nucleic acid Aps show unique targeting potential with high binding affinity to a variety of biological targets (e.g., genes, peptides, proteins, and even cells and organs). Aps have widely been used as the targeting agent, in large part due to their unique 3D structure, simplicity in synthesis and functionalization, high chemical flexibility, low immunogenicity and toxicity, and cell/tissue penetration capability in some cases. Here, in this review, we provide important insights on Ap-decorated multimodal nanosystems (NSs) and discuss their applications in targeted therapy and imaging of cancer.

Fucoidan-coated CuS nanoparticles for chemo-and photothermal therapy against cancer

In advanced cancer therapy, the combinational therapeutic effect of photothermal therapy (PTT) using near-infrared (NIR) light-responsive nanoparticles (NPs) and anti-cancer drug delivery-mediated chemotherapy has been widely applied. In the present study, using a facile, low-cost, and solution-based method, we developed and synthesized fucoidan, a natural polymer isolated from seaweed that has demonstrated anti-cancer effect, and coated NPs with it as an ideal candidate in chemo-photothermal therapy against cancer cells. Fucoidan-coated copper sulfide nanoparticles (F-CuS) act not only as a nanocarrier to enhance the intracellular delivery of fucoidan but also as a photothermal agent to effectively ablate different cancer cells (e.g., HeLa, A549, and K562), both in vitro and in vivo, with the induction of apoptosis under 808 nm diode laser irradiation. These results point to the potential usage of F-CuS in treating human cancer.

Synthesis and Bioevaluation of Iodine-131 Directly Labeled Cyclic RGD-PEGylated Gold Nanorods for Tumor-Targeted Imaging

Introduction

Radiolabeled gold nanoparticles play an important role in biomedical application. The aim of this study was to prepare iodine-131 (¹³¹I)-labeled gold nanorods (GNRs) conjugated with cyclic RGD and evaluate its biological characteristics for targeted imaging of integrin α_vβ₃-expressing tumors.

Methods

HS-PEG₍₅₀₀₀₎-COOH molecules were applied to replace CTAB covering the surface of bare GNRs for better biocompatibility, and c(RGDfK) peptides were conjugated onto the carboxyl terminal of GNR-PEG-COOH via EDC/NHS coupling reactions. The nanoconjugate was characterized, and ¹³¹I was directly tagged on the surface of GNRs via AuI bonds for SPECT/CT imaging. We preliminarily studied the characteristics of the probe and its feasibility for tumor-targeting SPECT/CT imaging.

Results

The [¹³¹I]GNR-PEG-cRGD probe was prepared in a simple and rapid manner and was stable in both PBS and fetal bovine serum. It targeted selectively and could be taken up by tumor cells mainly via integrin α_vβ₃-receptor-mediated endocytosis. In vivo imaging, biodistribution, and autoradiography results showed evident tumor uptake in integrin α_vβ₃-expressing tumors.

Conclusions

These promising results showed that this smart nanoprobe can be used for angiogenesis-targeted SPECT/CT imaging. Furthermore, the nanoprobe possesses a remarkable capacity for highly efficient photothermal conversion in the near-infrared region, suggesting its potential as a multifunctional theranostic agent.

Iron oxide nanoparticles - In vivo/in vitro biomedical applications and in silico studies

The review presents a broad overview of the biomedical applications of surface functionalized iron oxide nanoparticles (IONPs) as magnetic resonance imaging (MRI) agents for sensitive and precise diagnosis tool and synergistic combination with other imaging modalities. Then, the recent progress in therapeutic applications, such as hyperthermia is discussed and the available toxicity data of magnetic nanoparticles concerning in vitro and in vivo biomedical applications are addressed. This review also presents the available computer models using molecular dynamics (MD), Monte Carlo (MC) and density functional theory (DFT), as a basis for a complete understanding of the behaviour and morphology of functionalized IONPs, for improving NPs surface design and expanding the potential applications in nanomedicine.

Doxorubicin-conjugated D-glucosamine- and folate- bi-functionalised InP/ZnS quantum dots for cancer cells imaging and therapy

Nanoscaled quantum dots (QDs), with unique optical properties have been used for the development of theranostics. Here, InP/ZnS QDs were synthesised and functionalised with folate (QD-FA), D-glucosamine (QD-GA) or both (QD-FA-GA). The bi-functionalised QDs were further conjugated with doxorubicin (QD-FA-GA-DOX). Optimum Indium to fatty acid (In:MA) ratio was 1:3.5. Transmission electron microscopy (TEM) micrographs revealed spherical morphology for the QDs (11 nm). Energy-dispersive spectroscopy (EDS) spectrum confirmed the chemical composition of the QDs. MTT analysis in the OVCAR-3 cells treated with bare QDs, QD-FA, QD-GA, QD-FA-GA and QD-FA-GA-DOX (0.2 mg/mL of QDs) after 24 h indicated low toxicity for the bare QDs and functionalised QDs (about 80-90% cell viability). QD-FA-GA-DOX nanoparticles elicited toxicity in the cells. Cellular uptake of the engineered QDs were investigated in both folate receptor (FR)-positive OVCAR-3 cells and FR-negative A549 cells using fluorescence microscopy and FACS flow cytometry. The FA-functionalised QDs showed significantly higher uptake in the FR-positive OVCAR-3 cells, nonetheless the GA-functionalised QDs resulted in an indiscriminate uptake in both cell lines. In conclusion, our findings indicated that DOX-conjugated FA-armed QDs can be used as theranostics for simultaneous imaging and therapy of cancer.