Magnetic nanocomplexes for gene delivery applications.

Gene delivery is an indispensable technique for various biomedical applications such as gene therapy, stem cell engineering and gene editing. Recently, magnetic nanoparticles (MNPs) have received increasing attention for their use in promoting gene delivery efficiency. Under magnetic attraction, gene delivery efficiency using viral or nonviral gene carriers could be universally enhanced. Besides, magnetic nanoparticles could be utilized in magnetic resonance imaging or magnetic hyperthermia therapy, providing extra theranostic opportunities. In this review, recent research integrating MNPs with a viral or nonviral gene vector is summarized from both technical and application perspectives. Applications of MNPs in cutting-edge research technologies, such as biomimetic cell membrane nano-gene carriers, exosome-based gene delivery, cell-based drug delivery systems or CRISPR/Cas9 gene editing, are also discussed.

Stem Cell-Based Delivery of Gold/Chlorin e6 Nanocomplexes for Combined Photothermal and Photodynamic Therapy.

Combining photothermal and photodynamic modalities has shown encouraging therapeutic efficacy against various malignant cancers. Developing a delivery method for targeting and penetrating tumors is still a major focus for advancing this therapeutic approach. Herein, we report a novel strategy involving the utilization of stem cells as a live carrier to codeliver photothermal and photodynamic agents for cancer therapy. To this end, a novel gold nanorod (AuNR)-PEG-PEI (APP)/chlorin e6 (Ce6)-loaded adipose-derived stem cell (ADSC) system is proposed in which AuNRs and Ce6 act as the photothermal and photodynamic agents, respectively. To integrate with stem cells, the APP/Ce6 nanocomplexes exhibit advantages of low drug leakage, low cytotoxicity, efficient cellular uptake, and redox-responsive release. After loading of APP/Ce6 nanocomplexes, the ADSCs still maintained good tumor tropism and were capable of penetrating into the tumor spheroids. The photothermal effect induced by exposure to near-infrared light irradiation at 808 nm promoted the release of Ce6 from the stem cells into the surroundings and hence increased its availability to treat cancer cells. APP/Ce6-loaded ADSCs exerted effective dose-dependent in vitro anticancer activities via anticipated photothermal and photodynamic effects. In a murine CT26 colon cancer model, APP/Ce6 delivered by ADSCs resulted in superior tumor suppression compared to other delivery strategies. It was also noted that in vivo applications of APP/Ce6-loaded ADSCs did not induce noticeable detrimental effects on normal tissues/organs.

A preliminary study of Parkinson's gene therapy via sono-magnetic sensing gene vector for conquering extra/intracellular barriers in mice.

BACKGROUND: Non-virus genetic treatment for Parkinson's disease (PD) via plasmid glial cell-line derived neurotrophic factor (pGDNF) has shown potential for repairing damaged dopaminergic neurons. However, development of this gene therapy is largely hampered by the insufficient transfection efficiency as a result of the cell membrane, lysosome, and cytoskeleton meshwork. METHODS: In this study, we propose the use of polyethylenimine (PEI)-superparamagnetic iron oxide-plasmid DNA (pDNA)-loaded microbubbles (PSp-MBs) in conjunction with focused ultrasound (FUS) and two-step magnetic navigation to provide cavitation, proton sponge effect and magnetic effects to increase the efficiency of gene delivery. RESULTS: The gene transfection rate in the proposed system was 2.2-fold higher than that of the commercial agent (TransIT®-LT1). The transfection rate could be boosted ∼11%, ∼10%, and 6% by cavitation-magnetic hybrid enhanced cell membrane permeabilization, proton sponge effect, and magnetic-assisted cytoskeleton-reorganization, respectively. In vivo data suggested that effective gene delivery with this system results in a 3.2-fold increase in recovery of dopaminergic neurons and a 3.9-fold improvement in the motor behavior when compared to untreated genetic PD mice. CONCLUSIONS: We proposed that this novel FUS-magnetic hybrid gene delivery platform could be integrated with a variety of therapeutic genes for treating neurodegenerative diseases in the future.

Magnetic ternary nanohybrids for nonviral gene delivery of stem cells and applications on cancer therapy.

Cancer toxic agent-expressing mesenchymal stem cells (MSCs), which possess inherent tumor migration and penetration capabilities, have received increasing attention in cancer therapy. To ensure that this approach is successful, safe and efficient gene delivery methods for stem cell engineering must be developed. Methods: In this study, a magnetic ternary nanohybrid (MTN) system comprising biodegradable cationic materials, nucleic acids, and hyaluronic acid-decorated superparamagnetic iron oxide nanoparticles was proposed to construct stem cells expressing the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) via magnetic force and receptor dual targeting. Results: The CD44/magnetic force-mediated enhanced cellular uptake of MTNs by human mesenchymal cells (hMSCs) was confirmed in vitro. Highly efficient transfection was attained using MTNs without having any detrimental effect on the tumor migration and penetration capabilities of hMSCs. TRAIL expressed by the MTN-transfected hMSCs displayed strong anticancer effects through the activation of caspase-3 apoptotic signaling. The MTN-transfected hMSCs can be clearly imaged using magnetic resonance imaging techniques in vivo. In an orthotopic xenograft cancer model, MTN-transfected TRAIL-expressing hMSCs significantly suppressed the progression of human glioma (U87MG) and prolonged the survival of the animal. Conclusions: These findings suggest the considerable potential of utilizing MTNs for effectively constructing tumor toxic agent-expressing stem cells for treating malignant cancers.

Multifunctional PEGylated Albumin/IR780/Iron Oxide Nanocomplexes for Cancer Photothermal Therapy and MR Imaging.

A multifunctional albumin/superparamagnetic iron oxide nanoparticle (SPIO) nanocomplex system to deliver IR780, a photothermal agent, for cancer theranostic applications was proposed in this study. Single emulsion method was utilized to fabricate the human albumin/IR780/SPIO (HISP) nanocomplexes with a hydrophobic core (SPIO and IR780) and a hydrophilic shell (human serum albumin (HSA) and poly (ethylene glycol) (PEG)). Effects of PEGylation on the size and surface potential of nanocomplexes were analyzed. Nanospheres containing uniformly dispersed SPIO was observed using Transmission Electron Microscopy (TEM) imaging. As a potential magnetic resonance (MR) imaging agent, the HISP displayed dose-dependent T2-weighted imaging contrast (R2 = 81.6 mM-1s-1). Good colloidal stability was verified from the nanocomplexes under difference circumstances. The nanocomplexes were taken up by cancer cells efficiently and led to significant photothermal-mediated cancer cell death upon short-term near infrared (NIR) irradiation in vitro. Via intravenous injection, PEG-HISP can efficiently deliver IR780 to tumor sites and showed strong photothermal effect compared to free drug on the mice model. Significant tumor suppression by the photothermal treatments using PEG-HISP was demonstrated from the mice CT26 xenograft model. Good safety profile of the PEG-HISP was confirmed from histological examination and liver functional analysis. Taken together, the results suggest that PEG-HISP is a safe and robust nano-theranostic platform for advanced anti-cancer treatment.

Integrated self-assembling drug delivery system possessing dual responsive and active targeting for orthotopic ovarian cancer theranostics.

Ovarian cancers are the leading cause for mortality among gynecologic malignancies with five-year survival rate less than 30%. The purpose of this study is to develop a redox and pH-sensitive self-assembling hyaluronic acid nanoparticle with active targeting peptide for anticancer drug delivery. Anti-cancer drug is grafted onto hyaluronic acid (HA) via cis-aconityl linkage and disulfide bond to possess pH sensitivity and redox property, respectively. This conjugate is amphiphilic and can self-assemble into nanoparticle (NP) in aqueous solution. The results show that the nanoconjugate is successfully developed and the grafting ratio of cystamine (cys) is 17.8% with drug loading amount about 6.2% calculated by (1)H NMR spectra. The particle size is approximately 229.0 nm using dynamic light scatting measurement, and the morphology of nanoparticles is observed as spherical shape by transmission electron microscope. The pH and redox sensitivities are evaluated by changing either pH value or concentration of dithiothreitol in the medium. It is proved that the drug carrier is capable of achieving sustained controlled release of anti-cancer drug to 95% within 150 h. The intracellular uptake is observed by fluorescent microscope and the images show that conjugating luteinizing hormone-releasing hormone (LHRH) peptide can enhance specific uptake of nanoparticles by OVCAR-3 cancer cells; thus, resulting in inhibitory cell growth to less than 20% in 72 h in vitro. Orthotopic ovarian tumor model is also established to evaluate the therapeutic and diagnostic efficacy using non-invasive in vivo imaging system. The representative results demonstrate that LHRH-conjugated NPs possess a preferable tumor imaging capability and an excellent antitumor ability to almost 30% of original size in 20 days.

Redox-Sensitive Polymer/SPIO Nanocomplexes for Efficient Magnetofection and MR Imaging of Human Cancer Cells.

Magnetofection has received increasing attention for its great potential on gene therapy. To promote its clinical therapeutic applications, development of safe and effective magnetic nanocarriers is in high demand. Herein, we present a redox-sensitive polymer/metal nanocomplex system (PSPIO) for efficient magnetofection and magnet resonance imaging (MRI) on cancer cells. PSPIO was prepared by modifying SPIO with redox-sensitive polyethylenimine (SSPEI) via a ligand exchange process. PSPIO could efficiently condense plasmid DNA (pDNA) into nanoparticles, which exhibited several favorable properties for gene delivery, including protection of nucleic acids from enzymatic degradation, stable colloids in serum, and redox-responsive pDNA release. As a potential MR imaging agent, PSPIO displayed good magnetization (28.3 emu/g) and dose-dependent T2-weighted imaging contrast (R2 = 291.1 s(-1) mM(-1)) in vitro. The use of redox-sensitive SSPEI polymer contributed to much lower cytotoxicity of PSPIO compared to nondegradable bPEI25k. In vitro transfection efficiency of PSPIO was significantly enhanced under an external magnetic field. In the presence of serum, PSPIO exhibited higher transgene expression than SSPEI or bPEI25k polymer on mouse glioma (ALTS1C1) or human prostate cancer (PC3) cell lines. Taken together, it is demonstrated that PSPIO possess great potential for cancer gene therapy and molecular imaging.