Rapid and efficient magnetization of mesenchymal stem cells by dendrimer-functionalized magnetic nanoparticles

Advancing MRI with magnetic nanoparticles: a comprehensive review of translational research and clinical trials

The nexus of advanced technology and medical therapeutics has ushered in a transformative epoch in contemporary medicine. Within this arena, Magnetic Resonance Imaging (MRI) emerges as a paramount tool, intertwining the advancements of technology with the art of healing. MRI's pivotal role is evident in its broad applicability, spanning from neurological diseases, soft-tissue and tumour characterization, to many more applications. Though already foundational, aspirations remain to further enhance MRI's capabilities. A significant avenue under exploration is the incorporation of innovative nanotechnological contrast agents. Forefront among these are Superparamagnetic Iron Oxide Nanoparticles (SPIONs), recognized for their adaptability and safety profile. SPION's intrinsic malleability allows them to be tailored for improved biocompatibility, while their functionality is further broadened when equipped with specific targeting molecules. Yet, the path to optimization is not devoid of challenges, from renal clearance concerns to potential side effects stemming from iron overload. This review endeavors to map the intricate journey of SPIONs as MRI contrast agents, offering a chronological perspective of their evolution and deployment. We provide an in-depth current outline of the most representative and impactful pre-clinical and clinical studies centered on the integration of SPIONs in MRI, tracing their trajectory from foundational research to contemporary applications.

Prodigious therapeutic effects of combining mesenchymal stem cells with magnetic nanoparticles

Mesenchymal stem cells (MSCs) have gained wide-ranging reputation in the medical research community due to their promising regenerative abilities. MSCs can be isolated from various resources mostly bone marrow, Adipose tissues and Umbilical cord. Huge advances have been achieved in comprehending the possible mechanisms underlying the therapeutic functions of MSCs. Despite the proven role of MSCs in repairing and healing of many disease modalities, many hurdles hinder the transferring of these cells in the clinical settings. Among the most reported problems encountering MSCs therapy in vivo are loss of tracking signal post-transplantation, insufficient migration, homing and engraftment post-infusion, and undesirable differentiation at the site of injury. Magnetic nanoparticles (MNPs) have been used widely for various biomedical applications. MNPs have a metallic core stabilized by an outer coating material and their magnetic properties can be modulated by an external magnetic field. These magnetic properties of MNPs were found to enhance the quality of diagnostic imaging procedures and can be used to create a carrying system for targeted delivery of therapeutic substances mainly drug, genes and stem cells. Several studies highlighted the advantageous outcomes of combining MSCs with MNPs in potentiating their tracking, monitoring, homing, engraftment and differentiation. In this review, we will discuss the role of MNPs in promoting the therapeutic profile of MSCs which may improve the success rate of MSCs transplantation and solve many challenges that delay their clinical applicability.

A multistep in vitro hemocompatibility testing protocol recapitulating the foreign body reaction to nanocarriers

The development of drug nanocarriers based on polymeric, lipid and ceramic biomaterials has been paving the way to precision medicine, where the delivery of poorly soluble active compounds and personalized doses are made possible. However, the nano-size character of these carriers has been demonstrated to have the potential to elicit pathways of the host response different from those of the same biomaterials when engineered as larger size implants and of the drugs when administered without a carrier. Therefore, a specific regulatory framework needs to be made available that can offer robust scientific insights and provide safety data by reliable tests of these novel nano-devices. In this context, the present work presents a multistep protocol for the in vitro assessment of the hemocompatibility of nanocarriers of different physicochemical properties. Poly (ethyl butyl cyanoacrylate) nanoparticles and lipid-based (LipImage™ 815) nanoparticles of comparable hydrodynamic diameter were tested through a battery of assays using human peripheral blood samples and recapitulating the main pathways of the host response upon systemic administration; i.e., protein interactions, fibrinogen-platelet binding, cytotoxicity, and inflammatory response. The data showed the sensitivity and reproducibility of the methods adopted that were also demonstrated to determine individual variability as well as to discriminate between activation of pathways of inflammation and unintended release of inflammatory signaling caused by loss of cell integrity. Therefore, this multistep testing is proposed as a reliable protocol for nanoparticle development and emerging regulatory frameworks.

Recent advances of dendrimer in targeted delivery of drugs and genes to stem cells as cellular vehicles

Stem cells can be used to repair dysfunctional and injured (or cancerous) tissues by delivering therapeutics. However, in comparison with other cells, it is harder to transfect drugs or genes into stem cells. Dendrimers have been considered as efficient vectors to deliver both genes and drugs to stem cells due to their unique properties including adjustable molecular weight and size, low toxicity, high loading capacity, and having multiple peripheral chemical agents which can be functionalized to improve deliverance efficiency. In this review, we discuss dendrimer-mediated drug and gene delivery to stem cells as cellular vehicles and the role of this strategy in treating a variety of disorders via regenerative medicine approaches.

A comparative in vitro study of the effect of biospecific integrin recognition processes and substrate nanostructure on stem cell 3D spheroid formation

The in vitro study of the properties of the human mesenchymal stem cells as well as their manipulation in culture for clinical purposes depends on the elimination of artefacts caused by the lack of their natural environment. It is now widely accepted that mesenchymal stem cells should be studied when they are organised as 3D spheroids rather than fibroblast-like colonies. Although this can be achieved with the use of some extracellular matrix proteins or by non-adherent conditions these suffer of significant limitations. The recent development of synthetic substrates resembling the physicochemical and biochemical properties of the adult stem cell niche has prompted questions about the role played by nanotopography and receptor-mediated adhesion. In the present paper, the influence of two types of substrates bearing the same nanostructure, but exposing either a non-specific or an integrin-specific binding motif was studied. Carboxybetaine-tethered hyperbranched poly(ɛ-lysine) dendrons showed that the hyperbranched structure was fundamental to induce spheroid formation, but these were forming more slowly, were of reduced size and less stable than those growing on substrates based on the same hyperbranched structures that had been functionalised at their uppermost branching generation by a laminin amino acid sequence, i.e. YIGSR. The study shows that both nanostructure and biorecognition need to be combined to achieve a substrate for stem cell spheroid formation as that observed in vivo in the adult stem cell niche.

ESR as a monitoring method of the interactions between TEMPO-functionalized magnetic nanoparticles and yeast cells

Potential application of magnetic nanoparticles as drug carriers in medical treatment requires prior determination of their effects on cells. In this work different spin labels and magnetic nanoparticles functionalized with spin labels as well as their interaction with yeast cells were investigated using electron spin resonance (ESR) method. ESR was demonstrated to be a suitable method for monitoring of magnetic core and attached spin labels. Particular emphasis was placed on characterization of endocytosis and redox processes running inside the cell, resulting in recombination of spin labels. Such data could only be obtained at reduced temperature of ESR measurements.

Designing and Characterization of a Novel Delivery System for Improved Cellular Uptake by Brain Using Dendronised Apo-E-Derived Peptide

Neurodegenerative diseases (ND) are characterized by the progressive loss of neuronal structure or function mostly associated with neuronal death. The presence of the blood–brain barrier (BBB) is considered the main obstacle that prevents the penetration of almost all drugs rendering the diseases untreatable. Currently, one of the most promising approaches for drug delivery to the brain is by employing endogenous transcytosis to improve endothelial cell uptake. This study aimed to exploit this potential route of enhanced drug uptake through the design and characterization of low generations lysine dendrons with further functionalization of dendron with ApoE-derived peptide (AEP) ligand to improve cellular uptake and targeting of delivery to the brain. Dendrons and peptide were synthesized using solid phase peptide chemistry and the products were characterized by mass spectrometry and high performance liquid chromatography which confirmed the successful synthesis of dendrons and functionalization with the AEP. Cell viability and lactate dehydrogenase release were conducted to study the cytotoxicity of the materials against an immortalized brain endothelial cell line (bEnd.3) which demonstrated that no toxicity was seen at the concentration range used (up to 400 μM) for up to 48 h incubation. Cellular uptake of the synthesized molecules was examined using confocal microscopy and flow cytometer which clearly showed the cellular uptake of the dendronised carrier systems and that the highest percentage of cellular uptake was achieved with the AEP-functionalized dendron. This study has therefore demonstrated the successful synthesis of dendronised carrier systems with the potential to act as carriers for improved delivery and targeting the brain.

Development and validation of broad-spectrum magnetic particle labelling processes for cell therapy manufacturing

Background

Stem cells are increasingly seen as a solution for many health challenges for an ageing population. However, their potential benefits in the clinic are currently curtailed by technical challenges such as high cell dose requirements and point of care delivery, which pose sourcing and logistics challenges. Cell manufacturing solutions are currently in development to address the supply issue, and ancillary technologies such as nanoparticle-based labelling are being developed to improve stem cell delivery and enable post-treatment follow-up.

Methods

The application of magnetic particle (MP) labelling to potentially scalable cell manufacturing processes was investigated in a range of therapeutically relevant cells, including mesenchymal stromal cells (MSC), cardiomyocytes (CMC) and neural progenitor cells (ReN). The efficiency and the biological effect of particle labelling were analysed using fluorescent imaging and cellular assays.

Results

Flow cytometry and fluorescent microscopy confirmed efficient labelling of monolayer cultures. Viability was shown to be retained post labelling for all three cell types. MSC and CMC demonstrated higher tolerance to MP doses up to 100× the standard concentration. This approach was also successful for MP labelling of suspension cultures, demonstrating efficient MP uptake within 3 h, while cell viability was unaffected by this suspension labelling process. Furthermore, a procedure to enable the storing of MP-labelled cell populations to facilitate cold chain transport to the site of clinical use was investigated. When MP-labelled cells were stored in hypothermic conditions using HypoThermosol solution for 24 h, cell viability and differentiation potential were retained post storage for ReN, MSC and beating CMC.

Conclusions

Our results show that a generic MP labelling strategy was successfully developed for a range of clinically relevant cell populations, in both monolayer and suspension cultures. MP-labelled cell populations were able to undergo transient low-temperature storage whilst maintaining functional capacity in vitro. These results suggest that this MP labelling approach can be integrated into cell manufacturing and cold chain transport processes required for future cell therapy approaches.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0968-0) contains supplementary material, which is available to authorized users.

Magnetic field and nano-scaffolds with stem cells to enhance bone regeneration

Novel strategies utilizing magnetic nanoparticles (MNPs) and magnetic fields are being developed to enhance bone tissue engineering efficacy. This article first reviewed cutting-edge research on the osteogenic enhancements via magnetic fields and MNPs. Then the current developments in magnetic strategies to improve the cells, scaffolds and growth factor deliveries were described. The magnetic-cell strategies included cell labeling, targeting, patterning, and gene modifications. MNPs were incorporated to fabricate magnetic composite scaffolds, as well as to construct delivery systems for growth factors, drugs and gene transfections. The novel methods using magnetic nanoparticles and scaffolds with magnetic fields and stem cells increased the osteogenic differentiation, angiogenesis and bone regeneration by 2-3 folds over those of the controls. The mechanisms of magnetic nanoparticles and scaffolds with magnetic fields and stem cells to enhance bone regeneration were identified as involving the activation of signaling pathways including MAPK, integrin, BMP and NF-κB. Potential clinical applications of magnetic nanoparticles and scaffolds with magnetic fields and stem cells include dental, craniofacial and orthopedic treatments with substantially increased bone repair and regeneration efficacy.