Poly (dopamine) coated superparamagnetic iron oxide nanocluster for noninvasive labeling, tracking, and targeted delivery of adipose tissue-derived stem cells

Magnetic nanosheets: from iron oxide nanocubes to polydopamine embedded 2D clusters and their multi-purpose properties

We here develop stable bidimensional magnetic nanoclusters (2D-MNCs) of iron oxide nanocubes (IONCs) arranged in thin nanosheets of closed-packed nanocubes. The assembly occurs by means of a two-step approach: in the first one, the ionic surfactant, sodium dodecyl sulfate (SDS), acts as a transient water transfer agent and as 2D clustering agent to induce formation of a monolayer of nanocubes arranged in thin nanosheets. Next, the addition of dopamine followed by solution basification, induces the in situ polymerization of dopamine with a tunable shell tickness depending on the dopamine amount, which helps to compact the clusters and ensures the long term water stability of the clusters. TEM, cryo-EM, and SAXS techniques helped to reveal structural features of the 2D-clusters. The pH-dependent degradation properties of polydopamine, enable to disassemble the clusters in acidic tumour microenviroment leading to a four-fold increase in the magnetic particle imaging signal and a concomitant increase of the magnetic heat losses of these clusters, makes them appealing in magnetic hyperthermia, while the shortening of T2 relaxation time suggests their use as contrast in magnetic resonance imaging. Finally, with crystal violet dye, used as drug molecule, the feasibility to release payloads pre-encapsulated with the polydopamine polymer shell has been also shown.

Collagen Biocomposites Derived from Fish Waste: Doped and Cross-Linked with Functionalized Fe3O4 Nanoparticles and Their Comparative Studies with a Green Approach

Collagen-based nanobiocomposites can reabsorb and are biodegradable. These properties are effectively controlled by the number of cross-links. This study demonstrates an effortless and proficient approach for the functionalization of Fe₃O₄ NPs for cross-linking collagen obtained from biowaste, viz., fish scales of Lates Calcarifer, a marine origin. The size of Fe₃O₄ NPs (10-40 nm) was confirmed using particle size analysis. The physico-chemical properties of the aminosilane-coated Fe₃O₄ NPs cross-linked via succinylated collagen (FFCSC) were characterized using different analytical techniques and compared with succinylated collagen doped with Fe₃O₄ NPs (FDSC). Thermogravimetric analysis indicates cross-linked product FFCSC to be more stable than the FDSC. Also, the antibacterial effect was more pronounced for FFCSC than for FDSC nanobiocomposites. FFCSC exhibited improved mechanical properties which are essential for materials used for wound dressing purposes. Moreover, the cell viability of fibroblasts (3T3-L1) and their morphology studied by SEM and fluorescence microscopy showed biocompatibility of both FDSC and FFCSC. Thus, the current investigation, involves a waste to wealth approach where the collagen-based nanobiocomposites present an easy way to recycle the biowaste to value-added products using simple and clean methods, which are suitable for use in biomedical and environmental applications.

Synthesis and Characterization of a Biocompatible Nanoplatform Based on Silica-Embedded SPIONs Functionalized with Polydopamine

Superparamagnetic iron oxide nanoparticles (SPIONs) have gained increasing interest in nanomedicine, but most of those that have entered the clinical trials have been withdrawn due to toxicity concerns. Therefore, there is an urgent need to design low-risk and biocompatible SPION formulations. In this work, we present an original safe-by-design nanoplatform made of silica nanoparticles loaded with SPIONs and decorated with polydopamine (SPIONs@SiO2-PDA) and the study of its biocompatibility performance by an ad hoc thorough in vitro to in vivo nanotoxicological methodology. The results indicate that the SPIONs@SiO₂-PDA have excellent colloidal stability in serum-supplemented culture media, even after long-term (24 h) exposure, showing no cytotoxic or genotoxic effects in vitro and ex vivo. Physiological responses, evaluated in vivo using Caenorhabditis elegans as the animal model, showed no impact on fertility and embryonic viability, induction of an oxidative stress response, and a mild impact on animal locomotion. These tests indicate that the synergistic combination of the silica matrix and PDA coating we developed effectively protects the SPIONs, providing enhanced colloidal stability and excellent biocompatibility.

Nanotechnology-Assisted Cell Tracking

The usefulness of nanoparticles (NPs) in the diagnostic and/or therapeutic sector is derived from their aptitude for navigating intra- and extracellular barriers successfully and to be spatiotemporally targeted. In this context, the optimization of NP delivery platforms is technologically related to the exploitation of the mechanisms involved in the NP-cell interaction. This review provides a detailed overview of the available technologies focusing on cell-NP interaction/detection by describing their applications in the fields of cancer and regenerative medicine. Specifically, a literature survey has been performed to analyze the key nanocarrier-impacting elements, such as NP typology and functionalization, the ability to tune cell interaction mechanisms under in vitro and in vivo conditions by framing, and at the same time, the imaging devices supporting NP delivery assessment, and consideration of their specificity and sensitivity. Although the large amount of literature information on the designs and applications of cell membrane-coated NPs has reached the extent at which it could be considered a mature branch of nanomedicine ready to be translated to the clinic, the technology applied to the biomimetic functionalization strategy of the design of NPs for directing cell labelling and intracellular retention appears less advanced. These approaches, if properly scaled up, will present diverse biomedical applications and make a positive impact on human health.

Tracking Cell Viability for Adipose-Derived Mesenchymal Stem Cell-Based Therapy by Quantitative Fluorescence Imaging in the Second Near-Infrared Window

Cell survival rate determines engraftment efficiency in adipose-derived mesenchymal stem cell (ADSC)-based regenerative medicine. In vivo monitoring of ADSC viability to achieve effective tissue regeneration is a major challenge for ADSC therapy. Here, we developed an activated near-infrared II (NIR-II) fluorescent nanoparticle consisting of lanthanide-based down-conversion nanoparticles (DCNPs) and IR786s (DCNP@IR786s) for cell labeling and real-time tracking of ADSC viability in vivo. In dying ADSCs due to excessive ROS generation, absorption competition-induced emission of IR786s was destroyed, which could turn on the NIR-II fluorescent intensity of DCNPs at 1550 nm by 808 nm laser excitation. In contrast, the NIR-II fluorescent intensity of DCNPs was stable at 1550 nm by 980 nm laser excitation. This ratiometric fluorescent signal was precise and sensitive for tracking ADSC viability in vivo. Significantly, the nanoparticle could be applied to quantitively evaluate stem cell viability in real-time in vivo. Using this method, we successfully sought two small molecules including glutathione and dexamethasone that could improve stem cell engraftment efficiency and enhance ADSC therapy in a liver fibrotic mouse model. Therefore, we provide a potential strategy for real-time in vivo quantitative tracking of stem cell viability in ADSC therapy.

Antimicrobial and antioxidant therapy with bioactive plant molecules on Fe3O4 phytohybrid nanoplatforms

Background

Nanobiomedicines have gained increasing attention for their potential to improve efficacy and are emerging as a promising therapeutic paradigm. Magnetic nanoconjugates loaded with bioactive drugs have the advantage of sustained circulation in the bloodstream and significantly reduced toxicity of therapeutic agents in a precise manner. The well-developed surface chemistry of Fe3O4 has led to the development better tools, promoting them as nanoplatforms with potential technological applications in biomedical sciences.

Results

Fe3O4 phytohybrids with Laxmitaru extract as the primary coating and loaded with Eugenol and Ylang-Ylang essential oils were successfully synthesized. The X-ray diffraction technique has revealed the high purity nanoparticle materials, as no additional impurity peaks were observed. Fourier transform infra-red spectra have confirmed the presence of a primary coating of Laxmitaru extract and a secondary layer of essential oil, as additional peaks and broadening are observed in drug-loaded Fe3O4 nanoparticles. Magnetic susceptibility values indicate the material's superparamagnetic nature. Transmission electron microscopy images have ensured that the particles were spherical, monodispersed, and in the range of 4.30 nm to 13.98 nm. Antimicrobial studies show inhibition zones on the microorganisms S. Aureus and E. Coli with enhanced activity. Drug entrapment efficiency studies revealed the encapsulation of drug molecules onto Fe3O4-Laxmitaru composite. Dynamic light scattering studies confirm the increase in hydrodynamic size, indicating the loading of essential oils and the decrease in polydispersity index ensures monodispersed nanoparticles. The antioxidant study showed the essential oils retained their antioxidant activity even after they were conjugated on Fe3O4-Lax composites.

Conclusions

Laxmitaru phytochemical-coated Fe3O4 nanoparticles were successfully conjugated with Eugenol and Ylang-Ylang essential oils. Our results provide a model therapeutic approach for the development of new alternative strategies for enhancing antimicrobial and antioxidant therapy, with potential advantages in the field of nanobiomedicine.

Nanoparticles for Stem Cell Tracking and the Potential Treatment of Cardiovascular Diseases

Stem cell-based therapies have been shown potential in regenerative medicine. In these cells, mesenchymal stem cells (MSCs) have the ability of self-renewal and being differentiated into different types of cells, such as cardiovascular cells. Moreover, MSCs have low immunogenicity and immunomodulatory properties, and can protect the myocardium, which are ideal qualities for cardiovascular repair. Transplanting mesenchymal stem cells has demonstrated improved outcomes for treating cardiovascular diseases in preclinical trials. However, there still are some challenges, such as their low rate of migration to the ischemic myocardium, low tissue retention, and low survival rate after the transplantation. To solve these problems, an ideal method should be developed to precisely and quantitatively monitor the viability of the transplanted cells in vivo for providing the guidance of clinical translation. Cell imaging is an ideal method, but requires a suitable contrast agent to label and track the cells. This article reviews the uses of nanoparticles as contrast agents for tracking MSCs and the challenges of clinical use of MSCs in the potential treatment of cardiovascular diseases.

Effects of labeling human mesenchymal stem cells with superparamagnetic zinc-nickel ferrite nanoparticles on cellular characteristics and adipogenesis/osteogenesis differentiation

OBJECTIVE

An attractive cell source for stem cell-based therapy are WJ-MSCs. Hence, tracking WJ-MSCs using non-invasive imaging procedures (such as MRI) and contrast agents (Zn0.5Ni0.5Fe2O4, NFNPs) are required to evaluate cell distribution, migration, and differentiation.

RESULTS

Results showed that the bare and dextrin-coated NFNPs were internalized inside the WJ-MSCs and had no effect on the cell viability, proliferation, apoptosis, karyotyping, and morphology of WJ-MSCs up to 125 µg/mL. Besides, treated WJ-MSCs were differentiated into osteo/adipocyte-like cells. The expression of RUNX 2, SPP 1 (P < 0.05), and OCN (P > 0.05) genes in the WJ-MSCs treated with dextrin-coated NFNPs was higher than the untreated WJ-MSCs; and the expression of CFD, LPL, and PPAR-γ genes was reduced in WJ-MSCs treated with both NFNPs in comparison with the untreated WJ-MSCs (P > 0.05).

CONCLUSION

Overall, results showed that dextrin-coated NFNPs had no adverse effect on the cellular characteristics, proliferation, and differentiation of WJ-MSCs, and suggesting their potential clinical efficacy.

Enhancing therapeutic effects and in vivo tracking of adipose tissue-derived mesenchymal stem cells for liver injury using bioorthogonal click chemistry

Adipose tissue-derived mesenchymal stem cell (ADSC)-based therapy is attractive for liver diseases, but the long-term therapeutic outcome is still far from satisfaction due to the low hepatic engraftment efficiency of ADSC transplantation. Herein, we propose a strategy based on liver sinusoidal endothelial cell (LSEC)-targeting peptide modification and near infrared (NIR) fluorescent probe labeling for enhancing LSEC-barrier-migration ability and in vivo tracking of ADSCs in a liver injury mouse model. RLTRKRGLK (RK), a LSEC-targeted peptide, and indocyanine green (ICG), a FDA approved infrared fluorescent dye, were simultaneously modified on the ADSC surface via a bioorthogonal click reaction. The equipped ADSCs not only exhibited significant binding ability towards LSEC both in vitro and in vivo, but could also be monitored by NIR imaging in vivo. In particular, the RK-modified ADSCs showed remarkable higher hepatic accumulation as compared to unmodified ADSCs, resulting in better therapeutic outcomes. Therefore, this study provides a simple and convenient method for enhancing the homing of transplanted ADSCs to injured liver accompanying with in vivo cell tracking ability, which may shed light on accelerating the clinical translation of the ADSC-based therapy for liver diseases.

Improving Tumor Retention of Effector Cells in Adoptive Cell Transfer Therapies by Magnetic Targeting

Adoptive cell transfer therapy is a promising anti-tumor immunotherapy in which effector immune cells are transferred to patients to treat tumors. However, one of its main limitations is the inefficient trafficking of inoculated effector cells to the tumor site and the small percentage of effector cells that remain activated when reaching the tumor. Multiple strategies have been attempted to improve the entry of effector cells into the tumor environment, often based on tumor types. It would be, however, interesting to develop a more general approach, to improve and facilitate the migration of specific activated effector lymphoid cells to any tumor type. We and others have recently demonstrated the potential for adoptive cell transfer therapy of the combined use of magnetic nanoparticle-loaded lymphoid effector cells together with the application of an external magnetic field to promote the accumulation and retention of lymphoid cells in specific body locations. The aim of this review is to summarize and highlight the recent findings in the field of magnetic accumulation and retention of effector cells in tumors after adoptive transfer, and to discuss the possibility of using this approach for tumor targeting with chimeric antigen receptor (CAR) T-cells.

Antioxidant preconditioning improves therapeutic outcomes of adipose tissue-derived mesenchymal stem cells through enhancing intrahepatic engraftment efficiency in a mouse liver fibrosis model

BACKGROUND

Although it has been preclinically suggested that adipose tissue-derived mesenchymal stem cell (ADSC)-based therapy could effectively treat chronic liver diseases, the hepatic engraftment of ADSCs is still extremely low, which severely limits their long-term efficacy for chronic liver diseases. This study was designed to investigate the impact of antioxidant preconditioning on hepatic engraftment efficiency and therapeutic outcomes of ADSC transplantation in liver fibrotic mice.

METHODS

Liver fibrosis model was established by using intraperitoneal injection of carbon tetrachloride (CCl4) in the male C57BL/6 mice. Subsequently, the ADSCs with or without antioxidant pretreatment (including melatonin and reduced glutathione (GSH)) were administrated into fibrotic mice via tail vein injection. Afterwards, the ADSC transplantation efficiency was analyzed by ex vivo imaging, and the liver functions were assessed by biochemical analysis and histopathological examination, respectively. Additionally, a typical hydrogen peroxide (H2O2)-induced cell injury model was applied to mimic the cell oxidative injury to further investigate the protective effects of antioxidant preconditioning on cell migration, proliferation, and apoptosis of ADSCs.

RESULTS

Our data showed that antioxidant preconditioning could enhance the therapeutic effects of ADSCs on liver function recovery by reducing the level of AST, ALT, and TBIL, as well as the content of hepatic hydroxyproline and fibrotic area in liver tissues. Particularly, we also found that antioxidant preconditioning could enhance hepatic engraftment efficiency of ADSCs in liver fibrosis model through inhibiting oxidative injury.

CONCLUSIONS

Antioxidant preconditioning could effectively improve therapeutic effects of ADSC transplantation for liver fibrosis through enhancing intrahepatic engraftment efficiency by reducing oxidative injuries. These findings might provide a practical strategy for enhancing ADSC transplantation and therapeutic efficiency.

Assessment of Ploy Dopamine Coated Fe3O4 Nanoparticles for Melanoma (B16-F10 and A-375) Cells Detection

OBJECTIVE

Polydopamine coated iron oxide nanoparticles (Fe₃O₄@PDA NPs) were synthesized, characterized, and their MR imaging contrast agents and photothermal potency were evaluated on melanoma (B16-F10 and A-375) cells and normal skin cells. To this end, MTT assay, Fe concentration, and MR imaging of both coated and uncoated NPs were assessed in C57BL/6 mice.

METHODS

Fe3O4 nanoparticles were synthesized using co-precipitation, and coated with polydopamine. The cytotoxicity of Fe₃O₄ and Fe₃O₄@PDA NPs on melanoma cells, with different concentrations, were obtained using MTT assay. MR images and Fe concentrations of nanoprobe and nanoparticles were evaluated under in vivo conditions.

RESULTS

Findings indicated that uncoated Fe₃O₄ showed the highest toxicity in animal (B16-F10) cells at 450μg/ml after 72h, while the highest toxicity in human (A-375) cells were observed at 350μg/ml. These nanoparticles did not reveal any cytotoxicity to normal skin cells, despite having some toxicity features in A-375 cells. MR image signals in the tumor were low compared with other tissues. The iron concentration in the tumor was higher than that of other organs.

CONCLUSION

It is concluded that the cytotoxicity of Fe₃O₄@PDA was found to be significantly lower than uncoated nanoparticles (p <0.001), which allows some positive effects on reducing toxicity. The prepared nanoprobe may be used as a contrast agent in MR imaging.

Human Umbilical Cord Wharton's Jelly-Derived Mesenchymal Stem Cells Labeled with Mn2+ and Gd3+ Co-Doped CuInS2-ZnS Nanocrystals for Multimodality Imaging in a Tumor Mice Model

Mesenchymal stem cell (MSCs) therapy has recently received profound interest as a targeting platform in cancer theranostics because of inherent tumor-homing abilities. However, the terminal tracking of MSCs engraftment by fluorescent in situ hybridization, immuno-histochemistry, and flow-cytometry techniques to translate into clinics is still challenging because of a dearth of inherent MSCs-specific markers and FDA approval for genetic modifications of MSCs. To address this challenge, a cost-effective noninvasive imaging technology based on multifunctional nanocrystals (NCs) with enhanced detection sensitivity, spatial-temporal resolution, and deep-tissue diagnosis is needed to be developed to track the transplanted stem cells. A hassle-free labeling of human umbilical cord Wharton's Jelly (WJ)-derived MSCs with Mn²⁺ and Gd³⁺ co-doped CuInS₂-ZnS (CIS-ZMGS) NCs has been demonstrated in 2 h without requiring an electroporation process or transfection agents. It has been found that WJ-MSCs labeling did not affect their multilineage differentiation (adipocyte, osteocyte, chondrocyte), immuno-phenotypes (CD44⁺, CD105⁺, CD90⁺), protein (β-actin, vimentin, CD73, α-SMCA), and gene expressions. Interestingly, CIS-ZMGS-NCs-labeled WJ-MSCs exhibit near-infrared (NIR) fluorescence with a quantum yield of 84%, radiant intensity of ∼3.999 × 10¹¹ (p/s/cm²/sr)/(μW/cm²), magnetic relaxivity (longitudinal r₁ = 2.26 mM^-1 s^-1, transverse r₂ = 16.47 mM^-1 s^-1), and X-ray attenuation (78 HU) potential for early noninvasive multimodality imaging of a subcutaneous melanoma in B16F10-tumor-bearing C57BL/6 mice in 6 h. The ex vivo imaging and inductively coupled plasma mass-spectroscopy analyses of excised organs along with confocal microscopy and immunofluorescence of tumor results also significantly confirmed the positive tropism of CIS-ZMGS-NCs-labeled WJ-MSCs in the tumor environment. Hence, we propose the magnetofluorescent CIS-ZMGS-NCs-labeled WJ-MSCs as a next-generation nanobioprobe of three commonly used imaging modalities for stem cell-assisted anticancer therapy and tracking tissue/organ regenerations.

Antioxidants inhibit cell senescence and preserve stemness of adipose tissue-derived stem cells by reducing ROS generation during long-term in vitro expansion

BACKGROUND

Adipose tissue-derived mesenchymal stem cells (ADSCs) are promising candidates for regenerative medicine. However, long-term in vitro passaging leads to stemness loss and cell senescence of ADSCs, resulting in failure of ADSC-based therapy.

METHODS

In this study, ADSCs were treated with low dose of antioxidants (reduced glutathione and melatonin) with anti-aging and stem cell protection properties in the in vitro passaging, and the cell functions including stem cell senescence, cell migration, cell multidirectional differentiation potential, and ROS content were carefully analyzed.

RESULTS

We found that GSH and melatonin could maintain ADSC cell functions through reducing cell senescence and promoting cell migration, as well as by preserving stemness and multidirectional differentiation potential, through inhibiting ROS generation during long-term expansion of ADSCs.

CONCLUSIONS

Our results suggested that antioxidant treatment could efficiently prevent the dysfunction and preserve cell functions of ADSCs after long-term passaging, providing a practical strategy to facilitate ADSC-based therapy.

Magnetic Nanoparticles Attached to the NK Cell Surface for Tumor Targeting in Adoptive Transfer Therapies Does Not Affect Cellular Effector Functions

Adoptive cell transfer therapy is currently one of the most promising approaches for cancer treatment. This therapy has some limitations, however, such as the dispersion of in vivo-administered cells, causing only a small proportion to reach the tumor. Nanotechnological approaches could offer a solution for this drawback, as they can increase cell retention and accumulation in a region of interest. In particular, strategies employing magnetic nanoparticles (MNPs) to improve targeting of adoptively transferred T or NK cells have been explored in mice. In vivo magnetic retention is reported using the human NK cell line NK-92MI transfected with MNPs. Primary NK cells are nonetheless highly resistant to transfection, and thus we explore in here the possibility of attaching the MNPs to the NK cell surface to overcome this issue, and examine whether this association would affect NK effector functions. We assessed the attachment of MNPs coated with different polymers to the NK cell surface, and found that APS-MNP attached more efficiently to the NK-92MI cell surface. In association with MNPs, these cells preserved their main functions, exhibiting a continued capacity to degranulate, conjugate with and lyse target cells, produce IFN-γ, and respond to chemotactic signals. MNP-loaded NK-92MI cells were also retained in an in vitro capillary flow system by applying an EMF. A similar analysis was carried out in primary NK cells, isolated from mice, and expanded in vitro. These primary murine NK cells also maintained their functionality intact after MNP treatment and were successfully retained in vitro. This work therefore provides further support for using MNPs in combination with EMFs to favor specific retention of functional NK cells in a region of interest, which may prove beneficial to adoptive cell-therapy protocols.

Superparamagnetic iron oxide nanoparticles (SPIONs) as a multifunctional tool in various cancer therapies

Over the past two decades nanotechnology has become an important part of novel medical research. Researchers have made great progress in developing nanotechnology applications used for detecting and treating oncological diseases. Recently, many research groups have focused on the use of superparamagnetic iron oxide nanoparticles (SPIONs) in cancer treatment. Due to the range of therapeutic properties and possibilities of various modifications, SPIONs are a promising and multifunctional tool in various cancer therapies and may help to overcome the limitations of conventional therapies. Moreover, it is still necessary to develop new methods of treatment with expected properties, such as lower toxicity, long-lasting effectiveness and higher selectivity. Analyzing the literature data, we found that currently SPIONs are used in the transport of drugs, immunotherapy and hyperthermia. The main aim of this review is to present various cancer treatment therapies utilizing SPIONs, the importance of the experiments carried out by research groups and further perspectives in the nanotechnological use of SPIONs.

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

INTRODUCTION

Nowadays, nanoparticles (NPs) have attracted much attention in biomedical imaging due to their unique magnetic and optical characteristics. Superparamagnetic iron oxide nanoparticles (SPIONs) are the prosperous group of NPs with the capability to apply as magnetic resonance imaging (MRI) contrast agents. Radiolabeling of targeted SPIONs with positron emitters can develop dual positron emission tomography (PET)/MRI agents to achieve better diagnosis of clinical conditions.

METHODS

In this work, N,N,N-trimethyl chitosan (TMC)-coated magnetic nanoparticles (MNPs) conjugated to S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (DOTA) as a radioisotope chelator and bombesin (BN) as a targeting peptide (DOTA-BN-TMC-MNPs) were prepared and validated using fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and powder X-ray diffraction (PXRD) tests. Final NPs were radiolabeled with gallium-68 (68Ga) and evaluated in vitro and in vivo as a potential PET/MRI probe for breast cancer (BC) detection.

RESULTS

The DOTA-BN-TMC-MNPs with a particle size between 20 and 30 nm were efficiently labeled with 68Ga (radiochemical purity higher than 98% using thin layer chromatography (TLC)). The radiolabeled NPs showed insignificant toxicity (>74% cell viability) and high affinity (IC50=8.79 µg/mL) for the gastrin-releasing peptide (GRP)-avid BC T-47D cells using competitive binding assay against 99mTc-hydrazinonicotinamide (HYNIC)-gamma-aminobutyric acid (GABA)-BN (7-14). PET and MRI showed visible uptake of NPs by T-47D tumors in xenograft mouse models.

CONCLUSION

68Ga-DOTA-BN-TMC-MNPs could be a potential diagnostic probe to detect BC using PET/MRI technique.

T cells loaded with magnetic nanoparticles are retained in peripheral lymph nodes by the application of a magnetic field

Background

T lymphocytes are highly dynamic elements of the immune system with a tightly regulated migration. T cell-based transfer therapies are promising therapeutic approaches which in vivo efficacy is often limited by the small proportion of administered cells that reaches the region of interest. Manipulating T cell localisation to improve specific targeting will increase the effectiveness of these therapies. Nanotechnology has been successfully used for localized release of drugs and biomolecules. In particular, magnetic nanoparticles (MNPs) loaded with biomolecules can be specifically targeted to a location by an external magnetic field (EMF). The present work studies whether MNP-loaded T cells could be targeted and retained in vitro and in vivo at a site of interest with an EMF.

Results

T cells were unable to internalize the different MNPs used in this study, which remained in close association with the cell membrane. T cells loaded with an appropriate MNP concentration were attracted to an EMF and retained in an in vitro capillary flow-system. MNP-loaded T cells were also magnetically retained in the lymph nodes after adoptive transfer in in vivo models. This enhanced in vivo retention was in part due to the EMF application and to a reduced circulating cell speed within the organ. This combined use of MNPs and EMFs did not alter T cell viability or function.

Conclusions

These studies reveal a promising approach to favour cell retention that could be implemented to improve cell-based therapy.

Electronic supplementary material

The online version of this article (10.1186/s12951-019-0440-z) contains supplementary material, which is available to authorized users.

Design and Application of Cisplatin-Loaded Magnetic Nanoparticle Clusters for Smart Chemotherapy

One of the major challenges of drug delivery is the development of suitable carriers for therapeutic molecules. In this work, a novel nanoformulation based on superparamagnetic nanoclusters [magnetic nanocrystal clusters (MNCs)] is presented. In order to control the size of the nanoclusters and the density of magnetic cores, several parameters were evaluated and tuned. Then, MNCs were functionalized with a polydopamine layer (MNC@PDO) to improve their stability in aqueous solution, to increase density of functional groups and to obtain a nanosystem suitable for drug-controlled release. Finally, cisplatin was grafted on the surface of MNC@PDO to exploit the system as a magnetic field-guided anticancer delivery system. The biocompatibility of MNC@PDO and the cytotoxic effects of MNC@PDO-cisplatin complex were determined against human cervical cancer (HeLa) and human breast adenocarcinoma (MCF-7) cells. In vitro studies demonstrated that the MNC@PDO-cisplatin complexes inhibited the cellular proliferation by a dose-dependent effect. Therefore, by applying an external magnetic field, the released drug exerted its effect on a specific target area. In summary, the MNC@PDO nanosystem has a great potential to be used in targeted nanomedicine for the delivery of other drugs or biofunctional molecules.

Polydopamine/Transferrin Hybrid Nanoparticles for Targeted Cell-Killing

Polydopamine can form biocompatible particles that convert light into heat. Recently, a protocol has been optimized to synthesize polydopamine/protein hybrid nanoparticles that retain the biological function of proteins, and combine it with the stimuli-induced heat generation of polydopamine. We have utilized this novel system to form polydopamine particles, containing transferrin (PDA/Tf). Mouse melanoma cells, which strongly express the transferrin receptor, were exposed to PDA/Tf nanoparticles (NPs) and, subsequently, were irradiated with a UV laser. The cell death rate was monitored in real-time. When irradiated, the melanoma cells exposed to PDA/Tf NPs underwent apoptosis, faster than the control cells, pointing towards the ability of PDA/Tf to mediate UV-light-induced cell death. The system was also validated in an organotypic, 3D-printed tumor spheroid model, comprising mouse melanoma cells, and the exposure and subsequent irradiation with UV-light, yielded similar results to the 2D cell culture. The process of apoptosis was found to be targeted and mediated by the lysosomal membrane permeabilization. Therefore, the herein presented polydopamine/protein NPs constitute a versatile and stable system for cancer cell-targeting and photothermal apoptosis induction.

Untemplated Resveratrol-Mediated Polydopamine Nanocapsule Formation

Nanocapsules can be designed for applications including drug delivery, catalysis, and biological imaging. The mussel-inspired material polydopamine is a promising shell layer for nanocapsules because of its free radical scavenging capacity, ability to react with a broad range of functional molecules, lack of toxicity, and biodegradability. Previous reports of polydopamine nanocapsule formation have relied on a templating approach. Herein, we report a template-free approach to polydopamine nanocapsule formation in the presence of resveratrol, a naturally occurring anti-inflammatory and antioxidant compound found in red wine and grapes. Synthesis of nanocapsules occurs spontaneously in an ethanolic resveratrol/dopamine·HCl solution at pH 8.5. UV-vis absorbance spectroscopy and X-ray photoelectron spectroscopy indicate that resveratrol is incorporated into the nanocapsules. We also observed the formation of a soluble fluorescent dopamine-resveratrol adduct during synthesis, which was identified by high-performance liquid chromatography, UV-vis spectroscopy, and electrospray ionization mass spectrometry. Using transmission electron microscopy and dynamic light scattering, we studied the influence of solvent composition, dopamine concentration, and resveratrol/dopamine ratio on the nanocapsule diameter and shell thickness. The resulting nanocapsules have excellent free radical scavenging activity as measured by a 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Our work provides a convenient pathway by which resveratrol, and possibly other hydrophobic bioactive compounds, may be encapsulated within polydopamine nanocapsules.

Using tyrosinase as a tri-modality reporter gene to monitor transplanted stem cells in acute myocardial infarction

The study aimed to investigate the feasibility of noninvasive monitoring of bone marrow mesenchymal stem cells (MSCs) transduced with the tyrosinase reporter gene for acute myocardial infarction (AMI) with photoacoustic imaging (PAI), magnetic resonance imaging (MRI), and positron emission tomography (PET) in vitro and in vivo. MSCs were transduced with a lentivirus carrying a tyrosinase reporter gene. After transduction, the rate of ¹⁸F-5-fluoro-N-(2-[diethylamino]ethyl)picolinamide (¹⁸F-5-FPN) uptake was measured. PAI and MRI of stable cell lines expressing tyrosinase (TYR-MSCs) were performed in vitro. An AMI model was induced and verified. TYR-MSCs and MSCs were injected into the margins of the infarcted areas, and PAI, MRI, and PET images were acquired 1, 7, 14, 21, and 28 days after cell injection. Sham-operated models without injection were used as the control group. TYR-MSCs showed noticeably higher uptake of ¹⁸F-5-FPN and stronger signals in T1-weighted MRI and PAI than non-transduced MSCs. In vivo studies revealed prominent signals in the injected area of the infarcted myocardium on PAI/MRI/PET images, whereas no signal could be seen in rats injected with non-transduced MSCs or sham-operated rats. The uptake values of ¹⁸F-5-FPN in vivo showed a slight decrease over 28 days, whereas MRI and PAI signal intensity decreased dramatically. MSCs stably transduced with the tyrosinase reporter gene could be monitored in vivo in myocardial infarction models by PET, MRI, and PAI, providing a feasible and reliable method for checking the viability, location, and dwell time of transplanted stem cells.

Developing stem cell treatments for heart disease could be aided by adding the gene for tyrosinase, an enzyme that can reveal the location and activity of the cells. Transplanting stem cells derived from bone marrow into injured hearts shows promise for repairing the damage caused by heart attacks. Developing the treatment is hampered by limitations of existing methods for monitoring the fate of the transplanted stem cells. Researchers in China led by Xiaoli Lan at Huazhong University of Science and Technology tackled this limitation by adding the gene for tyrosinase into the stem cells. The enzyme produces the pigment melanin which both directly and by binding to other chemicals generates signals which can be identified by photoacoustic imaging, magnetic resonance imaging and positron emission tomography. Tests in cultured cells and rats confirm the procedure’s potential.

Micro-UFO (Untethered Floating Object): A Highly Accurate Microrobot Manipulation Technique

A new microrobot manipulation technique with high precision (nano level) positional accuracy to move in a liquid environment with diamagnetic levitation is presented. Untethered manipulation of microrobots by means of externally applied magnetic forces has been emerging as a promising field of research, particularly due to its potential for medical and biological applications. The purpose of the presented method is to eliminate friction force between the surface of the substrate and microrobot. In an effort to achieve high accuracy motion, required magnetic force for the levitation of the microrobot was determined by finite element method (FEM) simulations in COMSOL (version 5.3, COMSOL Inc., Stockholm, Sweden) and verified by experimental results. According to position of the lifter magnet, the levitation height of the microrobot in the liquid was found analytically, and compared with the experimental results head-to-head. The stable working range of the microrobot is between 30 µm to 330 µm, and it was confirmed in both simulations and experimental results. It can follow the given trajectory with high accuracy (<1 µm error avg.) at varied speeds and levitation heights. Due to the nano-level positioning accuracy, desired locomotion can be achieved in pre-specified trajectories (sinusoidal or circular). During its locomotion, phase difference between lifter magnet and carrier magnet has been observed, and relation with drag force effect has been discussed. Without using strong electromagnets or bulky permanent magnets, our manipulation approach can move the microrobot in three dimensions in a liquid environment.

Fabricating High-Performance T2-Weighted Contrast Agents via Adjusting Composition and Size of Nanomagnetic Iron Oxide

Magnetic relaxation switch demonstrated that the aggregated nanomagnetic iron oxide (NMIO) nanocrystal possessed a lower T₂ value and better relaxivity compared with monodispersed NMIO nanocrystal. However, we found that NMIO nanoclusters (NMIONCs) showed a different magnetic resonance (MR) imaging property in comparison with NMIO nanocrystals. Herein, three types of NMIONCs were used to explore the effects of size and compositions on the variations of magnetism and MR contrast ability. It was found that the transverse relaxation rate (r₂) of NMIONCs depended on the contact area between particles and water molecules. The smaller size and higher solubility could carry out higher contact area between NMIONCs and water molecules. Therefore, the monodispersed NMIONC showed a better T₂ contrast ability in comparison with the aggregated NMIONC. In addition, for NMIONCs with the same composition, the magnetism and contrast ability gradually increased with the particle size decreasing. In vivo, NMIONCs that possessed the best solubility and the smallest size showed the most effective MR contrast effect for the liver region of mice. As a result, the size and composition of NMIONCs played important roles for enhancing contrast behavior. This study provides a new idea to develop high-performance T₂ contrast agents by modulating the size and composition of particles.

Potential use of superparamagnetic iron oxide nanoparticles for in vitro and in vivo bioimaging of human myoblasts

Myocardial infarction (MI) is one of the most frequent causes of death in industrialized countries. Stem cells therapy seems to be very promising for regenerative medicine. Skeletal myoblasts transplantation into postinfarction scar has been shown to be effective in the failing heart but shows limitations such, e.g. cell retention and survival. We synthesized and investigated superparamagnetic iron oxide nanoparticles (SPIONs) as an agent for direct cell labeling, which can be used for stem cells imaging. High quality, monodisperse and biocompatible DMSA-coated SPIONs were obtained with thermal decomposition and subsequent ligand exchange reaction. SPIONs' presence within myoblasts was confirmed by Prussian Blue staining and inductively coupled plasma mass spectrometry (ICP-MS). SPIONs' influence on tested cells was studied by their proliferation, ageing, differentiation potential and ROS production. Cytotoxicity of obtained nanoparticles and myoblast associated apoptosis were also tested, as well as iron-related and coating-related genes expression. We examined SPIONs' impact on overexpression of two pro-angiogenic factors introduced via myoblast electroporation method. Proposed SPION-labeling was sufficient to visualize firefly luciferase-modified and SPION-labeled cells with magnetic resonance imaging (MRI) combined with bioluminescence imaging (BLI) in vivo. The obtained results demonstrated a limited SPIONs' influence on treated skeletal myoblasts, not interfering with basic cell functions.

Adipose tissue-derived stem cells ameliorate hyperglycemia, insulin resistance and liver fibrosis in the type 2 diabetic rats

BACKGROUND

Type 2 diabetes (T2D) is closely associated with liver fibrosis, but no effective treatments are currently available. This study was designed to investigate the therapeutic effects of ADSCs on insulin resistance, hyperglycemia, and liver fibrosis on T2D rats.

METHODS

We first established a T2D rat model with liver fibrosis by using the combination of a high-fat diet (HFD), low-dose streptozotocin (STZ), and carbon tetrachloride (CCl4). Subsequently, the model rats were administrated by tail vein injection of PBS or ADSCs, respectively. Thereafter, insulin resistance and liver function were assessed by biochemical analysis, ELISA, histopathological examination, and q-PCR assay, respectively. Moreover, the molecular mechanisms of ADSCs on the effect of the TGF-β1/SMAD3 signaling pathway were further analyzed.

RESULTS

Our data showed that ADSC transplantation significantly alleviated insulin resistance and hyperglycemia in the liver-injured T2D rats. We also found that ADSC transplantation could attenuate liver injury by improving liver function and inhibiting pathological changes of liver fibrosis, as well as through downregulation of TGF-β1 and phosphorylated SMAD3 both in vitro and in vivo.

CONCLUSIONS

These findings suggested that ADSC transplantation can ameliorate insulin resistance, hyperglycemia, and liver fibrosis via suppressing TGF-β1/SMAD3 signaling, which may provide a potential treatment strategy for liver fibrosis of T2D.

Fluorescent Magnetopolymersomes: A Theranostic Platform to Track Intracellular Delivery

We present a potential theranostic delivery platform based on the amphiphilic diblock copolymer polybutadiene-block-poly (ethylene oxide) combining covalent fluorescent labeling and membrane incorporation of superparamagnetic iron oxide nanoparticles for multimodal imaging. A simple self-assembly and labeling approach to create the fluorescent and magnetic vesicles is described. Cell uptake of the densely PEGylated polymer vesicles could be altered by surface modifications that vary surface charge and accessibility of the membrane active species. Cell uptake and cytotoxicity were evaluated by confocal microscopy, transmission electron microscopy, iron content and metabolic assays, utilizing multimodal tracking of membrane fluorophores and nanoparticles. Cationic functionalization of vesicles promoted endocytotic uptake. In particular, incorporation of cationic lipids in the polymersome membrane yielded tremendously increased uptake of polymersomes and magnetopolymersomes without increase in cytotoxicity. Ultrastructure investigations showed that cationic magnetopolymersomes disintegrated upon hydrolysis, including the dissolution of incorporated iron oxide nanoparticles. The presented platform could find future use in theranostic multimodal imaging in vivo and magnetically triggered delivery by incorporation of thermorepsonsive amphiphiles that can break the membrane integrity upon magnetic heating via the embedded superparamagnetic nanoparticles.

Ultrasmall Superparamagnetic Iron Oxide Nanoparticle for T2-Weighted Magnetic Resonance Imaging

A facile method to synthesize ultrasmall-sized supermagnetic iron oxide nanoparticles with good monodispersity and high relaxivity is desired for magnetic resonance imaging (MRI) technology. Herein, we have developed a one-step method to direct the formation of superparamagnetic iron oxide nanoparticle (uBSPIO) using albumin under mild conditions. The resulting uBSPIO possess ultrasmall size (4.78 ± 0.55 nm) and super high MR relaxivity (444.56 ± 8.82 mM^-1 s^-1). After grafted by the luteinizing hormone release hormone peptide (LHRH), the uBSPIO could targeted and accumulated in the tumor site. Finally, the uBSPIOs had good stability and did not induce cytotoxicity in vitro or major organ toxicity in vivo. The uBSPIOs are promising contrast agents for MRI.

Core-shell NaGdF4@CaCO3 nanoparticles for enhanced magnetic resonance/ultrasonic dual-modal imaging via tumor acidic micro-enviroment triggering

For cancer diagnosis, a paramount challenge still exists in the exploring of methods that can precisely discriminate tumor tissues from their surrounding healthy tissues with a high target-to-background signal ratio. Here, we report a NaGdF4@CaCO3-PEG core-shell nanoparticle which has the tumor acidic microenvironment enhanced imaging signals of ultrasound and magnetic resonance. Under the acidic conditions, the CaCO3 shell will gradually dissolve which then facilitate the interaction of NaGdF4 with the external aqueous environment to enhance water proton relaxation. Meanwhile, the CO2 bubbles generated by the CaCO3 dissolvement will generate strong elastic echo for US detection. The core-shell structure of NaGdF4@CaCO3-PEG can be observed by TEM, and its composition can be determined by STEM. The acid triggered generation of CO2 bubbles and the enhancement of MRI signal could be demonstrated in vitro, and the excellent dual-modal magnetic resonance/ultrasonic cancer imaging abilities of NaGdF4@CaCO3-PEG could be also proved at the tumor site in vivo. The here described proof-of-concept nanoparticles with pH triggered magnetic resonance/ultrasonic dual-modal imaging enhancement, may serve as a useful guide to develop various molecular imaging strategies for cancer diagnosis in the future.

Polydopamine Nanoparticles for Combined Chemo- and Photothermal Cancer Therapy

Cancer therapy with two different modalities can enhance treatment efficacy and reduce side effects. This paper describes a new method for combined chemo- and photothermal therapy of cancer using poly dopamine nanoparticles (PDA-NPs), where PDA-NPs serve not only as a photothermal agent with strong near infrared absorbance and high energy conversion efficiency, but also as a carrier to deliver cisplatin via interaction between cisplatin and catechol groups on PDA-NPs. Polyethylene glycol (PEG) was introduced through Michael addition reaction to improve the stability of PDA-NPs in physiological condition. A remarkable synergistic therapeutic effect has been achieved compared with respective single treatments. This work suggests that the PDA-based nanoplatform can be a universal scaffold for combined chemo- and photothermal therapy of cancer.

Recent progress in nanotechnology for stem cell differentiation, labeling, tracking and therapy

Nanotechnology advancements for stem cell differentiation, labeling, tracking and therapeutic applications in cardiac repair, bone, and liver regeneration are delineated.