Insights into the mechanism of magnetic particle assisted gene delivery

Still finding ways to augment the existing management of acute and chronic kidney diseases with targeted gene and cell therapies: Opportunities and hurdles

The rising global incidence of acute and chronic kidney diseases has increased the demand for renal replacement therapy. This issue, compounded with the limited availability of viable kidneys for transplantation, has propelled the search for alternative strategies to address the growing health and economic burdens associated with these conditions. In the search for such alternatives, significant efforts have been devised to augment the current and primarily supportive management of renal injury with novel regenerative strategies. For example, gene- and cell-based approaches that utilize recombinant peptides/proteins, gene, cell, organoid, and RNAi technologies have shown promising outcomes primarily in experimental models. Supporting research has also been conducted to improve our understanding of the critical aspects that facilitate the development of efficient gene- and cell-based techniques that the complex structure of the kidney has traditionally limited. This manuscript is intended to communicate efforts that have driven the development of such therapies by identifying the vectors and delivery routes needed to drive exogenous transgene incorporation that may support the treatment of acute and chronic kidney diseases.

A Detailed Review on Synthesis, Functionalization, Application, Challenges, and Current Status of Magnetic Nanoparticles in the Field of Drug Delivery and Gene Delivery System

For progression of health care system, it has always been a challenge to the researchers for formulation to a type of advanced drug delivery system which will have less toxicity, targeted delivery and will be highly biodegradable. Nano science or nanotechnology has been validated to be a successful method as of targeting the drug to its active site be due to its special physicochemical properties and size thereby reducing the dose of administration, increasing bioavailability, and also reducing toxicity. Magnetic nanoparticles recently in few decades have proved as an effective advanced drug delivery system for its elevated magnetic responsiveness, biocompatibility, elevated targeted drug delivery effectiveness, etc. The drug can be easily targeted to active site by application of external magnetic field. Among the various elements, nanoparticles prepared with magnetically active iron oxide or other iron-based spinel oxide nanoparticles are widely used due to its high electrical resistivity, mechanical hardness, chemical stability, etc. Owing to their easy execution towards drug delivery application, extensive research has been carried out in this area. This review paper has summarized all recent modifications of iron-based magnetically active nanoparticle based drug delivery system along with their synthesis, characterization, and applications.

Ultrasound and Magnetic Responsive Drug Delivery Systems for Cardiovascular Application

With the increasing insight into molecular mechanisms of cardiovascular disease, a promising solution involves directly delivering genes, cells, and chemicals to the infarcted myocardium or impaired endothelium. However, the limited delivery efficiency after administration fails to reach the therapeutic dose and the adverse off-target effect even causes serious safety concerns. Controlled drug release via external stimuli seems to be a promising method to overcome the drawbacks of conventional drug delivery systems (DDSs). Microbubbles and magnetic nanoparticles responding to ultrasound and magnetic fields respectively have been developed as an important component of novel DDSs. In particular, several attempts have also been made for the design and fabrication of dual-responsive DDS. This review presents the recent advances in the ultrasound and magnetic fields responsive DDSs in cardiovascular application, followed by their current problems and future reformation.

Recent Advancements of Specific Functionalized Surfaces of Magnetic Nano- and Microparticles as a Theranostics Source in Biomedicine

Magnetic nano- and microparticles (MNMPs) belong to a highly versatile class of colloids with actuator and sensor properties that have been broadly studied for their application in theranostics such as molecular imaging and drug delivery. The use of advanced biocompatible, biodegradable polymers and polyelectrolytes as MNMP coating materials is essential to ensure the stability of MNMPs and enable efficient drug release while at the same time preventing cytotoxic effects. In the past years, huge progress has been made in terms of the design of MNMPs. Especially, the understanding of coating formation with respect to control of drug loading and release kinetics on the molecular level has significantly advanced. In this review, recent advancements in the field of MNMP surface engineering and the applicability of MNMPs in research fields of medical imaging, diagnosis, and nanotherapeutics are presented and discussed. Furthermore, in this review the main emphasis is put on the manipulation of biological specimens and cell trafficking, for which MNMPs represent a favorable tool enabling transport processes of drugs through cell membranes. Finally, challenges and future perspectives for applications of MNMPs as theranostic nanomaterials are discussed.

A parallel and cascade control system: magnetofection of miR125b for synergistic tumor-association macrophage polarization regulation and tumor cell suppression in breast cancer treatment

Polarization regulation of tumor-association macrophages (TAMs) is a promising treatment method for tumors, but aiming at TAMs alone shows unsatisfactory therapeutic efficiency. Therefore, we designed a parallel and cascade control system for both macrophage polarization and tumor cell inhibition. The system is composed of cationic lipopeptides with an arginine-rich periphery (RLS) and anionic magnetic nanoparticles (MNPs) for fleet transfection of miR-125b. Based on the highly efficient magnetofection, miR-125b successfully shows a parallel effect on both M1, promoting polarization by targeting interferon regulatory factor 4 (IRF4) in macrophages, and tumor cell inhibition, by targeting ETS proto-oncogene 1 and cyclin- J. The cascading effect on M1-associated genes is upregulated by up to two orders of magnitude, while M2-associated genes are downregulated. Meanwhile, MNPs also have an effect on the TAM polarization and 4T1 tumor cell inhibition via inflammatory related gene expression and Fenton reaction. Further mimicking the co-culture of RAW264.7 and 4T1 cells in vitro confirmed the synergistic therapy effect. In the treatment of orthotopic breast cancer in mice, considerable M1 macrophage polarization was observed in the RM125b treated group, showing distinct tumor-suppressive effects, with a tumor weight reduction of 60% and tumor metastasis suppression of 50%.

Improving Magnetofection of Magnetic Polyethylenimine Nanoparticles into MG-63 Osteoblasts Using a Novel Uniform Magnetic Field

This study aimed to improve the magnetofection of MG-63 osteoblasts by integrating the use of a novel uniform magnetic field with low molecular weight polyethylenimine modified superparamagnetic iron oxide nanoparticles (PEI-SPIO-NPs). The excellent characteristics of PEI-SPIO-NPs such as size, zeta potential, the pDNA binding and protective ability were determined to be suitable for gene delivery. The novel uniform magnetic field enabled polyethylenimine-modified superparamagnetic iron oxide nanoparticles/pDNA complexes (PEI-SPIO-NPs/pDNA complexes) to rapidly and uniformly distribute on the surface of MG-63 cells, averting local transfection and decreasing disruption of the membrane caused by the centralization of positively charged PEI-SPIO-NPs, thereby increasing the effective coverage of magnetic gene carriers during transfection, and improving magnetofection efficiency. This innovative uniform magnetic field can be used to determine the optimal amount between PEI-SPIO-NPs and pDNA, as well as screen for the optimal formulation design of magnetic gene carrier under the homogenous conditions. Most importantly, the novel uniform magnetic field facilitates the transfection of PEI-SPIO-NPs/pDNA into osteoblasts, thereby providing a novel approach for the targeted delivery of therapeutic genes to osteosarcoma tissues as well as a reference for the treatment of other tumors.

Note: Magnetic targeting for enhancement of the activation efficiency of G protein-coupled receptor with a two-pair coil system

Insufficient contact of drug with target cells is a primary reason for limited efficiency of G protein-coupled receptor activation. To overcome this limitation, a simple approach based on magnetic targeting for enhancing drug delivery towards the cell surfaces using magnetic nanoparticles and a two-pair coil system consisting of Helmholtz and Maxwell coils was reported. As a proof of the concept, comparative experiments on G protein-coupled receptor activation process were carried out and results show that the efficiency of G protein-coupled receptor activation can be increased about 6 times in the experiments with the aid of the proposed magnetic targeting system.

Movement of magnetic nanoparticles in brain tissue: mechanisms and impact on normal neuronal function

Magnetic nanoparticles (MNPs) have been used as effective vehicles for targeted delivery of theranostic agents in the brain. The advantage of magnetic targeting lies in the ability to control the concentration and distribution of therapy to a desired target region using external driving magnets. In this study, we investigated the behavior and safety of MNP motion in brain tissue. We found that MNPs move and form nanoparticle chains in the presence of a uniform magnetic field, and that this chaining is influenced by the applied magnetic field intensity and the concentration of MNPs in the tissue. Using electrophysiology recordings, immunohistochemistry and fluorescent imaging we assessed the functional health of neurons and neural circuits and found no adverse effects associated with MNP motion through brain tissue.

FROM THE CLINICAL EDITOR

Much research has been done to test the use of nanocarriers for gaining access across the blood brain barrier (BBB). In this respect, magnetic nanoparticles (MNPs) are one of the most studied candidates. Nonetheless, the behavior and safety of MNP once inside brain tissue remains unknown. In this article, the authors thus studied this very important subject.

Inorganic nanovectors for nucleic acid delivery

Nucleic acids show immense potential to treat cancer, acquired immune deficiency syndrome, neurological diseases and other incurable human diseases. Upon systemic administration, they encounter a series of barriers and hence barely reach the site of action, the cell. Intracellular delivery of nucleic acids is facilitated by nanovectors, both viral and non-viral. A major advantage of non-viral vectors over viral vectors is safety. Nanovectors evaluated specifically for nucleic acid delivery include polyplexes, lipoplexes and other cationic carrier-based vectors. However, more recently there is an increased interest in inorganic nanovectors for nucleic acid delivery. Nevertheless, there is no comprehensive review on the subject. The present review would cover in detail specific properties and types of inorganic nanovectors, their preparation techniques and various biomedical applications as therapeutics, diagnostics and theranostics. Future prospects are also suggested.

Insight into the efficient transfection activity of a designed low aggregated magnetic polyethyleneimine/DNA complex in serum-containing medium and the application in vivo

In vitro fate of designed low aggregated magnetic polyethyleneimine/DNA (MPD-cc) complexes and in vivo study via systemic administration.

Magnetically deliverable calcium phosphate nanoparticles for localized gene expression

Iron oxide doped tricalcium phosphate nanoparticles can be used to achieve a spatially controlled green fluorescent gene delivery without using potentially cytotoxic agents.

Comprehensive study of DNA binding on iron (II,III) oxide nanoparticles with a positively charged polyamine three-dimensional coating

Iron (II,III) oxide Fe3O4 nanoparticles (25 and 50 nm NPs) are grafted with amine groups through silanization in order to generate a positively charged coating for binding negatively charged species including DNA molecules. The spatial nature of the coating changes from a 2-D-functionalized surface (monoamines) through a layer of amine oligomers (diethylenetriamine or DETA, about 1 nm in length) to a 3-D layer of polyamine (polyethyleneimine or PEI, thickness ≥3.5 nm). These Fe3O4-PEI NPs were prepared by binding short-chain PEI polymers to the iodopropyl groups grafted on the NP surface. In this work, the surface charge density, or zeta potential, of the nanoparticles is found not to be the only factor influencing the DNA binding capacity, which also seems not to be affected by their buffering capacity profile in the range of pH 4-10. This study also allows the investigation of this 3-D effect on the surface of a nanoparticle as opposed to conventional 2-D amine functionalization. The flexibility of the PEI coating, which consists of only 1, 2, and 3° amines, on the nanoparticle surface has a significant influence on the overall DNA binding capacity and the binding efficiency (or N/P ratio). These polyamine-functionalized nanoparticles can be used in the purification of biomolecules and the delivery of drugs and large biomolecules.

Development of a novel lipophilic, magnetic nanoparticle for in vivo drug delivery

The aim of the present study was to evaluate the transfection potential of chitosan-coated, green-fluorescent magnetic nanoparticles (MNPs) (chi-MNPs) after encapsulation inside polyethylglycol (PEG)ylated liposomes that produced lipid-encapsulated chitosan-coated MNPs (lip-MNPs), and also to evaluate how these particles would distribute in vivo after systemic injection. The transfection potential of both chi-MNPs and lip-MNPs was evaluated in vitro in rat brain endothelial 4 (RBE4) cells with and without applying a magnetic field. Subsequently, the MNPs were evaluated in vivo in young rats. The in vitro investigations revealed that the application of a magnetic field resulted in an increased cellular uptake of the particles. The lip-MNPs were able to transfect the RBE4 cells with an incidence of approximately 20% of a commercial transfection agent. The in vivo distribution studies revealed that lip-MNPs had superior pharmacokinetic properties due to evasion of the RES, including hepatic Kuppfer cells and macrophages in the spleen. In conclusion, we were able to design a novel lipid-encapsulated MNP with the ability to carry genetic material, with favorable pharmacokinetic properties, and under the influence of a magnetic field with the capability to mediate transfection in vitro.

Intracellular Delivery of siRNA by Polycationic Superparamagnetic Nanoparticles

The siRNA transfection efficiency of nanoparticles (NPs), composed of a superparamagnetic iron oxide core modified with polycationic polymers (poly(hexamethylene biguanide) or branched polyethyleneimine), were studied in CHO-K1 and HeLa cell lines. Both NPs demonstrated to be good siRNA transfection vehicles, but unmodified branched polyethyleneimine (25 kD) was superior on both cell lines. However, application of an external magnetic field during transfection (magnetofection) increased the efficiency of the superparamagnetic NPs. Furthermore, our results reveal that these NPs are less toxic towards CHO-K1 cell lines than the unmodified polycationic-branched polyethyleneimine (PEI). In general, the external magnetic field did not alter the cell's viability nor it disrupted the cell membranes, except for the poly(hexamethylene biguanide)-modified NP, where it was observed that in CHO-K1 cells application of the external magnetic field promoted membrane damage. This paper presents new polycationic superparamagnetic NPs as promising transfection vehicles for siRNA and demonstrates the advantages of magnetofection.

Current status of gene delivery: spotlight on nanomaterial-polymer hybrids

Gene therapy aims to treat human disorders by introducing genetic materials into specific target cells or tissues. Despite the curability for the origIn of diseases by restoring missing functionalities, no technical feasibility of gene therapy has been established due to the lack of safe and efficient gene delivery systems. The emergence of nanotechnology has provided an opportunity to create nanomaterials that are suitable for the biomedical applications. Nanomaterials integrated with cationic polymers offer novel platforms that allow not only easy incorporation of genetic materials through electrostatic interactions but also further modifications to be upgraded to theranostics. In this article, current status of gene delivery utilizing hybrid nanomaterials that are composed of novel nanoplatforms and cationic polymers are highlighted. In particular, different strategies employed for the construction of nanomaterial-polymer hybrids are described.

Hybrid polyethylenimine and polyacrylic acid-bound iron oxide as a magnetoplex for gene delivery

Low transfection efficiency is always an issue when cationic polymers are used as a nonviral gene vector in the physiological condition, especially in the presence of proteins. A cationic magnetic nanoparticle (MNP) may be an alternative to solve this problem because a magnetic field can help to attract the MNP and internalize it into cells. The aim of this study was to determine the potency of polyethylenimine (PEI)-decorated MNPs for efficiently complexing and delivering plasmid DNA in vitro with the help of a magnetic field. PEI is associated with poly(acrylic acid)-bound superparamagnetic iron oxide (PAAIO) through electrostatic interactions (PEI-PAAIO). PEI-PAAIO formed stable polyplexes with pDNA in the presence and absence of 10% fetal bovine serum (FBS) and could be used for magnetofection. The effect of a static magnetic field on the cytotoxicity, cellular uptake, and transfection efficiency of PEI-PAAIO/pDNA was evaluated with and without 10% FBS. Magnetofection efficacy in HEK 293T cells and U87 cells containing 10% FBS was significantly improved in the presence of an external magnetic field. The amount of internalized iron was quantitatively measured using an inductively coupled plasma-optical emission spectrometer and directly visualized using Prussian blue staining. The internalized pDNA was visualized using a confocal laser scanning microscope.

Silica-iron oxide magnetic nanoparticles modified for gene delivery: a search for optimum and quantitative criteria

PURPOSE

To optimize silica-iron oxide magnetic nanoparticles with surface phosphonate groups decorated with 25-kD branched polyethylenimine (PEI) for gene delivery.

METHODS

Surface composition, charge, colloidal stabilities, associations with adenovirus, magneto-tranduction efficiencies, cell internalizations, in vitro toxicities and MRI relaxivities were tested for the particles decorated with varying amounts of PEI.

RESULTS

Moderate PEI-decoration of MNPs results in charge reversal and destabilization. Analysis of space and time resolved concentration changes during centrifugation clearly revealed that at >5% PEI loading flocculation gradually decreases and sufficient stabilization is achieved at >10%. The association with adenovirus occurred efficiently at levels over 5% PEI, resulting in the complexes stable in 50% FCS at a PEI-to-iron w/w ratio of ≥7%; the maximum magneto-transduction efficiency was achieved at 9-12% PEI. Primary silica iron oxide nanoparticles and those with 11.5% PEI demonstrated excellent r(2)* relaxivity values (>600 s(-1)(mM Fe)(-1)) for the free and cell-internalized particles.

CONCLUSIONS

Surface decoration of the silica-iron oxide nanoparticles with a PEI-to-iron w/w ratio of 10-12% yields stable aqueous suspensions, allows for efficient viral gene delivery and labeled cell detection by MRI.

Fe3O4-PEI-RITC magnetic nanoparticles with imaging and gene transfer capability: development of a tool for neural cell transplantation therapies

PURPOSE

To develop Fe(3)O(4)-PEI-RITC magnetic nanoparticles with multimodal MRI-fluorescence imaging and transfection capability, for use in neural cell replacement therapies.

METHODS

The Fe(3)O(4)-PEI-RITC MNPs were synthesised through a multi-step chemical grafting procedure: (i) Silanisation of MNPs with 3-iodopropyltrimethoxysilane; (ii) PEI coupling with iodopropyl groups on the MNP surface; and (iii) RITC binding onto the PEI coating. The cell labelling and transfection capabilities of these particles were evaluated in astrocytes derived from primary cultures.

RESULTS

Fe(3)O(4)-PEI-RITC MNPs did not exert acute toxic effects in astrocytes (at ≤ 6 days). Cells showed rapid and extensive particle uptake with up to 100% cellular labelling observed by 24 h. MRI and microscopy studies demonstrate that the particles have potential for use in bimodal MR-fluorescence imaging. Additionally, the particles were capable of delivering plasmids encoding reporter protein (approximately 4 kb) to astrocytes, albeit with low efficiencies.

CONCLUSIONS

Multifunctional Fe(3)O(4)-PEI-RITC MNPs were successfully prepared using a multi-step synthetic pathway, with the PEI and RITC chemically bound onto the MNP surface. Their combined MR-fluorescence imaging capabilities with additional potential for transfection applications can provide a powerful tool, after further development, for non-invasive cell tracking and gene transfer to neural transplant populations.

Magnetically enhanced nucleic acid delivery. Ten years of magnetofection-progress and prospects

Nucleic acids carry the building plans of living systems. As such, they can be exploited to make cells produce a desired protein, or to shut down the expression of endogenous genes or even to repair defective genes. Hence, nucleic acids are unique substances for research and therapy. To exploit their potential, they need to be delivered into cells which can be a challenging task in many respects. During the last decade, nanomagnetic methods for delivering and targeting nucleic acids have been developed, methods which are often referred to as magnetofection. In this review we summarize the progress and achievements in this field of research. We discuss magnetic formulations of vectors for nucleic acid delivery and their characterization, mechanisms of magnetofection, and the application of magnetofection in viral and nonviral nucleic acid delivery in cell culture and in animal models. We summarize results that have been obtained with using magnetofection in basic research and in preclinical animal models. Finally, we describe some of our recent work and end with some conclusions and perspectives.

Magnetic targeting strategies in gene delivery

Gene delivery is a process of the insertion of transgenes into cells with the purpose to obtain the expression of encoded protein. The therapeutic application of this process is termed gene therapy, which is becoming a promising instrument to treat genetic and acquired diseases. Although numerous methods of gene transfer have already been developed, including biological, physical and chemical approaches, the optimal strategy has to be discovered. Importantly, it should be effective, selective and safe to be translated to the clinic. Magnetic targeting has been demonstrated as an effective strategy to decrease side effects of gene transfer, while increasing the selectivity and efficiency of the applied vector. This article will focus on the latest progress in the development of different magnetic vectors, based on both viral and nonviral gene delivery agents. It will also include a description of magnetic targeting applications in stem cells and in vivo, which has gained interest in recent years due to the rapid development of technology.

Application of magnetic nanoparticles to gene delivery

Nanoparticle technology is being incorporated into many areas of molecular science and biomedicine. Because nanoparticles are small enough to enter almost all areas of the body, including the circulatory system and cells, they have been and continue to be exploited for basic biomedical research as well as clinical diagnostic and therapeutic applications. For example, nanoparticles hold great promise for enabling gene therapy to reach its full potential by facilitating targeted delivery of DNA into tissues and cells. Substantial progress has been made in binding DNA to nanoparticles and controlling the behavior of these complexes. In this article, we review research on binding DNAs to nanoparticles as well as our latest study on non-viral gene delivery using polyethylenimine-coated magnetic nanoparticles.