In vivo safety evaluation of polyarginine coated magnetic nanovectors

The Peptide Functionalized Inorganic Nanoparticles for Cancer-Related Bioanalytical and Biomedical Applications

In order to improve their bioapplications, inorganic nanoparticles (NPs) are usually functionalized with specific biomolecules. Peptides with short amino acid sequences have attracted great attention in the NP functionalization since they are easy to be synthesized on a large scale by the automatic synthesizer and can integrate various functionalities including specific biorecognition and therapeutic function into one sequence. Conjugation of peptides with NPs can generate novel theranostic/drug delivery nanosystems with active tumor targeting ability and efficient nanosensing platforms for sensitive detection of various analytes, such as heavy metallic ions and biomarkers. Massive studies demonstrate that applications of the peptide-NP bioconjugates can help to achieve the precise diagnosis and therapy of diseases. In particular, the peptide-NP bioconjugates show tremendous potential for development of effective anti-tumor nanomedicines. This review provides an overview of the effects of properties of peptide functionalized NPs on precise diagnostics and therapy of cancers through summarizing the recent publications on the applications of peptide-NP bioconjugates for biomarkers (antigens and enzymes) and carcinogens (e.g., heavy metallic ions) detection, drug delivery, and imaging-guided therapy. The current challenges and future prospects of the subject are also discussed.

Tailoring Iron Oxide Nanoparticles for Efficient Cellular Internalization and Endosomal Escape

Iron oxide nanoparticles (IONs) have been widely explored for biomedical applications due to their high biocompatibility, surface-coating versatility, and superparamagnetic properties. Upon exposure to an external magnetic field, IONs can be precisely directed to a region of interest and serve as exceptional delivery vehicles and cellular markers. However, the design of nanocarriers that achieve an efficient endocytic uptake, escape lysosomal degradation, and perform precise intracellular functions is still a challenge for their application in translational medicine. This review highlights several aspects that mediate the activation of the endosomal pathways, as well as the different properties that govern endosomal escape and nuclear transfection of magnetic IONs. In particular, we review a variety of ION surface modification alternatives that have emerged for facilitating their endocytic uptake and their timely escape from endosomes, with special emphasis on how these can be manipulated for the rational design of cell-penetrating vehicles. Moreover, additional modifications for enhancing nuclear transfection are also included in the design of therapeutic vehicles that must overcome this barrier. Understanding these mechanisms opens new perspectives in the strategic development of vehicles for cell tracking, cell imaging and the targeted intracellular delivery of drugs and gene therapy sequences and vectors.

MXD3 antisense oligonucleotide with superparamagnetic iron oxide nanoparticles: A new targeted approach for neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor in children. The outcomes for aggressive forms of NB remain poor. The aim of this study was to develop a new molecular-targeted therapy for NB using an antisense oligonucleotide (ASO) and superparamagnetic iron oxide (SPIO) nanoparticles (NPs), as a delivery vehicle, targeting the transcription regulator MAX dimerization protein 3 (MXD3). We previously discovered that MXD3 was highly expressed in high-risk NB, acting as an anti-apoptotic factor; therefore, it can be a good therapeutic target. In this study, we developed two ASO-NP complexes using electrostatic conjugation to polyethylenimine-coated SPIO NPs and chemical conjugation to amphiphilic polymers on amine-functionalized SPIO NPs. Both ASO-NP complexes demonstrated MXD3 knockdown, which resulted in apoptosis in NB cells. ASO chemically-conjugated NP complexes have the potential to be used in the clinic as they showed great efficacy with minimum NP-associated cytotoxicity.

Sustaining Intravitreal Residence With L-Arginine Peptide-Conjugated Nanocarriers

Purpose

Intravitreal injection of antiangiogenic agents is becoming a standard treatment for neovascular retinal diseases. Sustained release of therapeutics by injecting colloidal carriers is a promising approach to reduce the injection frequency, which reduces treatment burdens and the risk of complications on patients. Such sustained release often requires carriers to have micrometer-scale dimension that, however, can potentially promote glaucoma and inflammation. Small, polycationic particles can be immobilized in vitreous through multiple cooperative ionic interactions with hyaluronic acid of the vitreous interior, but such particles are generally toxic. Here, we synthesized and examined a biocompatible dextran-based nanocarrier (<50 nm in diameter) conjugated with cationic peptides containing L-arginine with minimal toxicity, aiming to provide sustained release of therapeutic drugs in vitreous.

Methods

We synthesized the nanocarriers with condensed cholesteryl dextran (CDEX) as core material. Cationic peptides containing 1 to 4 arginine groups, along with fluorescence tags, were conjugated to the CDEX surface. We monitored the carrier diffusion rate ex vivo and half-lives in vivo in rodent vitreous using fluorescence imaging. We evaluated the toxicity by histological examinations at the second, third, eighth, and thirty-sixth week.

Results

The diffusion rate of nanocarriers was inversely related to zeta potential values in freshly isolated vitreous humor. We observed increased half-lives in vivo with increasing zeta potential (up to 240 days). Histological examinations confirmed no adverse effects on ocular morphology and organization.

Conclusions

We demonstrated the potential of L-arginine peptide-conjugated nanocarriers toward safe and sustained therapeutic release system for posterior eye diseases.

Recent Advances in Nanomaterials for Gene Delivery-A Review

With the rapid development of nanotechnology in the recent decade, novel DNA and RNA delivery systems for gene therapy have become available that can be used instead of viral vectors. These non-viral vectors can be made of a variety of materials, including inorganic nanoparticles, carbon nanotubes, liposomes, protein and peptide-based nanoparticles, as well as nanoscale polymeric materials. They have as advantages over viral vectors a decreased immune response, and additionally offer flexibility in design, allowing them to be functionalized and targeted to specific sites in a biological system with low cytotoxicity. The focus of this review is to provide an overview of novel nanotechnology-based methods to deliver DNA and small interfering RNAs into biological systems.

Theranostic nanoparticles based on bioreducible polyethylenimine-coated iron oxide for reduction-responsive gene delivery and magnetic resonance imaging

Theranostic nanoparticles based on superparamagnetic iron oxide (SPIO) have a great promise for tumor diagnosis and gene therapy. However, the availability of theranostic nanoparticles with efficient gene transfection and minimal toxicity remains a big challenge. In this study, we construct an intelligent SPIO-based nanoparticle comprising a SPIO inner core and a disulfide-containing polyethylenimine (SSPEI) outer layer, which is referred to as a SSPEI-SPIO nanoparticle, for redox-triggered gene release in response to an intracellular reducing environment. We reveal that SSPEI-SPIO nanoparticles are capable of binding genes to form nano-complexes and mediating a facilitated gene release in the presence of dithiothreitol (5–20 mM), thereby leading to high transfection efficiency against different cancer cells. The SSPEI-SPIO nanoparticles are also able to deliver small interfering RNA (siRNA) for the silencing of human telomerase reverse transcriptase genes in HepG2 cells, causing their apoptosis and growth inhibition. Further, the nanoparticles are applicable as T2-negative contrast agents for magnetic resonance (MR) imaging of a tumor xenografted in a nude mouse. Importantly, SSPEI-SPIO nanoparticles have relatively low cytotoxicity in vitro at a high concentration of 100 μg/mL. The results of this study demonstrate the utility of a disulfide-containing cationic polymer-decorated SPIO nanoparticle as highly potent and low-toxic theranostic nano-system for specific nucleic acid delivery inside cancer cells.