Sandwich-type Au-PEI/DNA/PEI-Dexa nanocomplex for nucleus-targeted gene delivery in vitro and in vivo

The menace of severe adverse events and deaths associated with viral gene therapy and its potential solution

Over the past decade, in vivo gene replacement therapy has significantly advanced, resulting in market approval of numerous therapeutics predominantly relying on adeno-associated viral vectors (AAV). While viral vectors have undeniably addressed several critical healthcare challenges, their clinical application has unveiled a range of limitations and safety concerns. This review highlights the emerging challenges in the field of gene therapy. At first, we discuss both the role of biological barriers in viral gene therapy with a focus on AAVs, and review current landscape of in vivo human gene therapy. We delineate advantages and disadvantages of AAVs as gene delivery vehicles, mostly from the safety perspective (hepatotoxicity, cardiotoxicity, neurotoxicity, inflammatory responses etc.), and outline the mechanisms of adverse events in response to AAV. Contribution of every aspect of AAV vectors (genomic structure, capsid proteins) and host responses to injected AAV is considered and substantiated by basic, translational and clinical studies. The updated evaluation of recent AAV clinical trials and current medical experience clearly shows the risks of AAVs that sometimes overshadow the hopes for curing a hereditary disease. At last, a set of established and new molecular and nanotechnology tools and approaches are provided as potential solutions for mitigating or eliminating side effects. The increasing number of severe adverse reactions and, sadly deaths, demands decisive actions to resolve the issue of immune responses and extremely high doses of viral vectors used for gene therapy. In response to these challenges, various strategies are under development, including approaches aimed at augmenting characteristics of viral vectors and others focused on creating secure and efficacious non-viral vectors. This comprehensive review offers an overarching perspective on the present state of gene therapy utilizing both viral and non-viral vectors.

Nanoparticle-mediated gene delivery of TRAIL to resistant cancer cells: A review

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), also known as APO2L, has emerged as a highly potential anticancer agent because of its capacity to effectively trigger apoptosis in tumor cells by specifically binding to either of its death receptors (DR4 or DR5) while having no adverse effects on normal cells. Nevertheless, its practical use has been hindered by its inefficient pharmacokinetics characteristics, the challenges involved in its administration and delivery to targeted cells, and the resistance exhibited by most cancer cells towards TRAIL. Gene therapy, as a promising approach would be able to potentially circumvent TRAIL-based cancer therapy challenges mainly through localized TRAIL expression and generating a bystander impact. Among different strategies, using nanoparticles in TRAIL gene delivery allows for precise targeting, and overcoming TRAIL resistance by combination therapy. In this review, we go over potential mechanisms by which cancer cells achieve resistance to TRAIL and provide an overview of different carriers for delivering of the TRAIL gene to resistant cancer cells, focusing on different types of nanoparticles utilized in this context. We will also explore the challenges, and investigate future perspectives of this nanomedicine approach for cancer therapy.

Glucocorticoids-based prodrug design: Current strategies and research progress

Attributing to their broad pharmacological effects encompassing anti-inflammation, antitoxin, and immunosuppression, glucocorticoids (GCs) are extensively utilized in the clinic for the treatment of diverse diseases such as lupus erythematosus, nephritis, arthritis, ulcerative colitis, asthma, keratitis, macular edema, and leukemia. However, long-term use often causes undesirable side effects, including metabolic disorders-induced Cushing's syndrome (buffalo back, full moon face, hyperglycemia, etc.), osteoporosis, aggravated infection, psychosis, glaucoma, and cataract. These notorious side effects seriously compromise patients' quality of life, especially in patients with chronic diseases. Therefore, glucocorticoid-based advanced drug delivery systems for reducing adverse effects have received extensive attention. Among them, prodrugs have the advantages of low investment, low risk, and high success rate, making them a promising strategy. In this review, we propose the strategies for the design and summarize current research progress of glucocorticoid-based prodrugs in recent decades, including polymer-based prodrugs, dendrimer-based prodrugs, antibody-drug conjugates, peptide-drug conjugates, carbohydrate-based prodrugs, aliphatic acid-based prodrugs and so on. Besides, we also raise issues that need to be focused on during the development of glucocorticoid-based prodrugs. This review is expected to be helpful for the research and development of novel GCs and prodrugs.

Controllable and reusable seesaw circuit based on nicking endonucleases

Seesaw circuits are essential for molecular computing and biosensing. However, a notable limitation of seesaw circuits lies in the irreversible depletion of components, precluding the attainment of system recovery and rendering nucleic acid circuits non-reusable. We developed a brand-new method for creating controllable and reusable seesaw circuits. By using the nicking endonucleases Nt.BbvCI and Nt.Alwi, we removed "functional components" while keeping the "skeletal components" for recurrent usage. T-inputs were introduced, increasing the signal-to-noise ratio of AND logic from 2.68 to 11.33 and demonstrating compatibility. We identified the logic switching feature and verified that it does not impair circuit performance. We also built intricate logic circuits, such as OR-AND gate, to demonstrate the versatility of our methodology. This controllable reusability extends the applications of nanotechnology and bioengineering, enhancing the practicality and efficiency of these circuits across various domains.

Nanomedicine in cancer therapy

Cancer remains a highly lethal disease in the world. Currently, either conventional cancer therapies or modern immunotherapies are non-tumor-targeted therapeutic approaches that cannot accurately distinguish malignant cells from healthy ones, giving rise to multiple undesired side effects. Recent advances in nanotechnology, accompanied by our growing understanding of cancer biology and nano-bio interactions, have led to the development of a series of nanocarriers, which aim to improve the therapeutic efficacy while reducing off-target toxicity of the encapsulated anticancer agents through tumor tissue-, cell-, or organelle-specific targeting. However, the vast majority of nanocarriers do not possess hierarchical targeting capability, and their therapeutic indices are often compromised by either poor tumor accumulation, inefficient cellular internalization, or inaccurate subcellular localization. This Review outlines current and prospective strategies in the design of tumor tissue-, cell-, and organelle-targeted cancer nanomedicines, and highlights the latest progress in hierarchical targeting technologies that can dynamically integrate these three different stages of static tumor targeting to maximize therapeutic outcomes. Finally, we briefly discuss the current challenges and future opportunities for the clinical translation of cancer nanomedicines.

Polyethyleneimine/polyethylene glycol-conjugated gold nanoparticles as nanoscale positive/negative controls in nanotoxicology: testing in frog embryo teratogenesis assay-Xenopus and mammalian tissue culture system

Despite the great potential of using positively charged gold nanoparticles (AuNPs) in nanomedicine, no systematic studies have been reported on their synthesis optimization or colloidal stability under physiological conditions until a group at the National Institute of Standards and Technology recently succeeded in producing remarkably stable polyethyleneimine (PEI)-coated AuNPs (Au-PEI). This improved version of Au-PEI (Au-PEI25kB) has increased the demand for toxicity and teratogenicity information for applications in nanomedicine and nanotoxicology. In vitro assays for Au-PEI25kB in various cell lines showed substantial active cytotoxicity. For advanced toxicity research, the frog embryo teratogenesis assay-Xenopus (FETAX) method was employed in this study. We observed that positively-charged Au-PEI25kB exhibited significant toxicity and teratogenicity, whereas polyethylene glycol conjugated AuNPs (Au-PEG) used as comparable negative controls did not. There is a characteristic avidity of Au-PEI25kB for the jelly coat, the chorionic envelope (also known as vitelline membrane) and the cytoplasmic membrane, as well as a barrier effect of the chorionic envelope observed with Au-PEG. To circumvent these characteristics, an injection-mediated FETAX approach was utilized. Like treatment with the FETAX method, the injection of Au-PEI25kB severely impaired embryo development. Notably, the survival/concentration curve that was steep when the standard FETAX approach was employed became gradual in the injection-mediated FETAX. These results suggest that Au-PEI25kB may be a good candidate as a nanoscale positive control material for nanoparticle analysis in toxicology and teratology.

TRAIL in the Treatment of Cancer: From Soluble Cytokine to Nanosystems

The death ligand tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF cytokine superfamily, has long been recognized for its potential as a cancer therapeutic due to its low toxicity against normal cells. However, its translation into a therapeutic molecule has not been successful to date, due to its short in vivo half-life associated with insufficient tumor accumulation and resistance of tumor cells to TRAIL-induced killing. Nanotechnology has the capacity to offer solutions to these limitations. This review provides a perspective and a critical assessment of the most promising approaches to realize TRAIL's potential as an anticancer therapeutic, including the development of fusion constructs, encapsulation, nanoparticle functionalization and tumor-targeting, and discusses the current challenges and future perspectives.

Turning Hot into Cold: Immune Microenvironment Reshaping for Atherosclerosis Attenuation Based on pH-Responsive shSiglec-1 Delivery System

Current atherosclerosis treatment is based on a combination of cholesterol-lowering medication and low-fat diets; however, the clinical effect is unsatisfactory. It has been shown that the level of immune cell infiltration and pro-inflammatory factors in the atherosclerotic immune microenvironment (AIM) play important roles in the development and progression of atherosclerosis. Therefore, we hypothesized that reshaping "hot AIM" into "cold AIM" could attenuate atherosclerosis. For this purpose, we designed a pH-responsive and charge-reversible nanosystem, referred to as Au-PEI/shSiglec-1/PEI-acetylsalicylic acid (ASPA NPs) to effectively deliver shSiglec-1, which blocked the interactions between macrophages with CD8⁺ T/NKT cells, thus inhibiting immune cell infiltration. Further, we demonstrated that acetylsalicylic acid (ASA), detached from the pH-responsive PEI-ASA polymer, and inhibited lipid accumulation in macrophage, thereby decreasing the lipid antigen presentation. Additionally, reduced macrophage-produced inflammatory factors by ASA and low CD8⁺ T/NKT cell infiltration levels synergistically inhibit Th17 cell differentiation, thus further dramatically attenuating inflammation in AIM by decreasing the IL-17A production. Eventually, ASPA NPs efficiently reshaped AIM by inhibiting immune cell infiltration, lipid antigen presentation, and pro-inflammation, which provided a feasible therapeutic strategy for atherosclerosis immunotherapy.

Expression of PEI-coated gold nanoparticles carrying exogenous gene in periwinkle mesophyll cells and its practice in Huanglongbing research

Huanglongbing (HLB) is a devastating disease of citrus, which is mostly caused by Candidatus Liberibacter asiaticus (CLas). To realize the specific application of nano-transgenic technology in HLB, AuNPs-PEI (Gold Nanoparticles-Polyethylenimine) was used to carry foreign genes into the leaves of periwinkle (Catharanthus roseus) by infiltration. Here, we demonstrated that NPR1-GFP protein expression was observed from the 12th hour to the 10th day after infiltrating AuNPs-PEI-pNPR1 (Arabidopsis thaliana nonexpressor of pathogenesis-related gene 1)-GFP. Fluorescence of mCherry was observed 6 h after AuNPs-PEI-pNLS (nuclear localization signal sequence)-mCherry infiltration and fluorescence of FAM was observed in the nucleus 4 h after AuNPs-PEI-FAM-siRNA_NPR1 infiltration. In addition, NPR1-GFP expression in CLas-infected periwinkle leaves was significantly higher than that in healthy periwinkle leaves after infiltration. Our work confirmed that the expression of exogenous NPR1-GFP could reduce the CLas titers by promoting the expression of PR (pathogenesis related) genes and ICS (isochorismate synthase) gene.

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AuNPs-PEI-FAM-siRNA_NPR1 entered the nucleus within 4 h after infiltration

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AuNPs-PEI-pNLS-mCherry expressed the corresponding protein within 6 h

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AuNPs-PEI-pNPR1-GFP continued to express the corresponding protein for 14 days

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After AuNPs-PEI-pNPR1-GFP infiltration for 2 days, CLas titer decreased significantly

Modification of Branched Polyethyleneimine Using Mesquite Gum for Its Improved Hemocompatibility

In the present study, the modification of branched polyethyleneimine (b-PEI) was carried out using mesquite gum (MG) to improve its hemocompatibility to be used in biomedical applications. In the copolymer synthesis process (carboxymethylated mesquite gum grafted polyethyleneimine copolymer (CBX-MG-PEI), an MG carboxymethylation reaction was initially carried out (carboxymethylated mesquite gum (CBX-MG). Subsequently, the functionalization between CBX-MG and b-PEI was carried out using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as crosslinking agents. The synthesis products were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Thermogravimetric analysis showed that CBX-MG and CBX-MG-PEI presented a lower decomposition temperature than MG. The CBX-MG-PEI has a high buffer capacity in the pH range of 4 to 7, similar to the b-PEI. In addition, the CBX-MG-PEI showed an improvement in hemocompatibility in comparison with the b-PEI. The results showed a non-hemolytic property at doses lower than 0.1 µg/mL (CBX-MG-PEI). These results allow us to propose that this copolymer be used in transfection, polymeric nanoparticles, and biomaterials due to its physicochemical and hemocompatibility properties.

Engineered Cytokines for Cancer and Autoimmune Disease Immunotherapy

Cytokine signaling is critical to a range of biological processes including cell development, tissue repair, aging, and immunity. In addition to acting as key signal mediators of the immune system, cytokines can also serve as potent immunotherapies with more than 20 recombinant products currently Food and Drug Administration (FDA)-approved to treat conditions including hepatitis, multiple sclerosis, arthritis, and various cancers. Yet despite their biological importance and clinical utility, cytokine immunotherapies suffer from intrinsic challenges that limit their therapeutic potential including poor circulation, systemic toxicity, and low tissue- or cell-specificity. In the past decade in particular, methods have been devised to engineer cytokines in order to overcome such challenges and here, the myriad strategies are reviewed that may be employed in order to improve the therapeutic potential of cytokine and chemokine immunotherapies with applications in cancer and autoimmune disease therapy, as well as tissue engineering and regenerative medicine. For clarity, these strategies are collected and presented as they vary across size scales, ranging from single amino acid substitutions, to larger protein-polymer conjugates, nano/micrometer-scale particles, and macroscale implants. Together, this work aims to provide readers with a timely view of the field of cytokine engineering with an emphasis on early-stage therapeutic approaches.

The reversal of chemotherapy-induced multidrug resistance by nanomedicine for cancer therapy

Multidrug resistance (MDR) of cancer is a persistent problem in chemotherapy. Scientists have considered the overexpressed efflux transporters responsible for MDR and chemotherapy failure. MDR extremely limits the therapeutic effect of chemotherapy in cancer treatment. Many strategies have been applied to solve this problem. Multifunctional nanoparticles may be one of the most promising approaches to reverse MDR of tumor. These nanoparticles can keep stability in the blood circulation and selectively accumulated in the tumor microenvironment (TME) either by passive or active targeting. The stimuli-sensitive or organelle-targeting nanoparticles can release the drug at the targeted-site without exposure to normal tissues. In order to better understand reversal of MDR, three main strategies are concluded in this review. First strategy is the synergistic effect of chemotherapeutic drugs and ABC transporter inhibitors. Through directly inhibiting overexpressed ABC transporters, chemotherapeutic drugs can enter into resistant cells without being efflux. Second strategy is based on nanoparticles circumventing over-expressed efflux transporters and directly targeting resistance-related organelles. Third approach is the combination of multiple therapy modes overcoming cancer resistance. At last, numerous researches demonstrated cancer stem-like cells (CSCs) had a deep relation with drug resistance. Here, we discuss two different drug delivery approaches of nanomedicine based on CSC therapy.

Revisiting the role of TRAIL/TRAIL-R in cancer biology and therapy

TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, can induce apoptosis in cancer cells, sparing normal cells when bound to its associated death receptors (DR4/DR5). This unique mechanism makes TRAIL a potential anticancer therapeutic agent. However, clinical trials of recombinant TRAIL protein and TRAIL receptor agonist monoclonal antibodies have shown disappointing results due to its short half-life, poor pharmacokinetics and the resistance of the cancer cells. This review summarizes TRAIL-induced apoptotic and survival pathways as well as mechanisms leading to apoptotic resistance. Recent development of methods to overcome cancer cell resistance to TRAIL-induced apoptosis, such as protein modification, combination therapy and TRAIL-based gene therapy, appear promising. We also discuss the challenges and opportunities in the development of TRAIL-based therapies for the treatment of human cancers.

Parallel Multiparameter Study of PEI-Functionalized Gold Nanoparticle Synthesis for Biomedical Applications: Part 2. Elucidating the Role of Surface Chemistry and Polymer Structure in Performance

Elucidating the polyethyleneimine (PEI) chemistry to predictively and reproducibly synthesize gold nanoparticle (AuNP)-PEI conjugates with desired properties has been elusive despite evaluation in numerous studies and reported enhanced properties. The lack of reproducible methods to control the core size and stability has led to contradictory results for performance and safety; thus, advancement of the conjugate platform for commercial use has likely been hindered. Recently, we reported a robust, reproducible method for synthesizing PEI-functionalized AuNPs (Au-PEIs), providing an opportunity to investigate structure-function relationships and to further investigate synthesis parameters affecting performance, where only materials stable in biological media are candidates for use. The properties of Au-PEIs prepared by the optimized reduction of HAuCl₄ using four different structural variants of PEI changed significantly with the PEI molar mass and backbone form (branched or linear). In the present study using our previously reported synthesis procedure, comprehensive analysis of properties such as size distribution, surface plasmon resonance (SPR), morphological state, surface functionality, and the shelf life has been systematically evaluated to elucidate the role of surface chemistry and reactive groups involved in conjugation, as a function of conjugate size and morphology. Being important for commercial adoption, the chemistry was related to the observed colloidal stability of the product in relevant media, including exposure to physiological variables such as salt, pH, proteins, and thermal changes. Overall, this work advances progress toward smart design of engineered nanoscale drug delivery systems and devices by providing unreported details of contributions affecting formation, stability, and fate.

Photothermally Modulatable and Structurally Disintegratable Sub-8-nm Au1Ag9 Embedded Nanoblocks for Combination Cancer Therapy Produced by Plug-in Assembly

As well as the exploration of translatable delivery nanosystems for cancer therapeutic agents, the development of automatable continuous-flow manufacturing technology comprising digitally controlled reactions for the on-demand production of pharmaceuticals is an important challenge in anticancer nanomedicine. Most attempts to resolve these issues have involved the development of alternative reactions, formulations, or constructs containing stimulus components aimed at producing multiple approaches for highly efficacious combination cancer therapies. However, there has been no report of a platform based on plug-in execution that enables continuous-flow manufacture in a compact, reconfigurable manner, although an optimal platform technology may be a prerequisite for the timely translation of recently developed nanomedicines. To this end, we describe the development of a platform toward digitizable, continuous manufacture by a serial combination of plug-in reactionwares (heating plates, a spraying cup, and a photochamber) for single-pass flow fabrication. Specifically, we fabricated three different composite nanoblocks consisting of Au₁Ag₉ (<8 nm; stimulus component), docetaxel (an anticancer drug), and bovine serum albumin (a protective and targeting agent) using our system, with the result of producing nanoblocks with photothermally modulatable and structurally disintegratable properties. These were examined for effectiveness in near-infrared-induced chemothermal cancer therapy and renal excretion of Au₁Ag₉ particles and exhibited high anticancer efficacy and warrantable biosafety.

TRAIL in oncology: From recombinant TRAIL to nano- and self-targeted TRAIL-based therapies

TNF-related apoptosis-inducing ligand (TRAIL) selectively induces the apoptosis pathway in tumor cells leading to tumor cell death. Because TRAIL induction can kill tumor cells, cancer researchers have developed many agents to target TRAIL and some of these agents have entered clinical trials in oncology. Unfortunately, these trials have failed for many reasons, including drug resistance, off-target toxicities, short half-life, and specifically in gene therapy due to the limited uptake of TRAIL genes by cancer cells. To address these drawbacks, translational researchers have utilized drug delivery platforms. Although, these platforms can improve TRAIL-based therapies, they are unable to sufficiently translate the full potential of TRAIL-targeting to clinically viable products. Herein, we first summarize the complex biology of TRAIL signaling, including TRAILs cross-talk with other signaling pathways and immune cells. Next, we focus on known resistant mechanisms to TRAIL-based therapies. Then, we discuss how nano-formulation has the potential to enhance the therapeutic efficacy of TRAIL protein. Finally, we specify strategies with the potential to overcome the challenges that cannot be addressed via nanotechnology alone, including the alternative methods of TRAIL-expressing circulating cells, tumor-targeting bacteria, viruses, and exosomes.

TRAIL-based gene delivery and therapeutic strategies

TRAIL (tumor necrosis factor-related apoptosis-inducing ligand), also known as APO2L, belongs to the tumor necrosis factor family. By binding to the death receptor 4 (DR4) or DR5, TRAIL induces apoptosis of tumor cells without causing side toxicity in normal tissues. In recent years TRAIL-based therapy has attracted great attention for its promise of serving as a cancer drug candidate. However, the treatment efficacy of TRAIL protein was under expectation in the clinical trials because of the short half-life and the resistance of cancer cells. TRAIL gene transfection can produce a "bystander effect" of tumor cell killing and provide a potential solution to TRAIL-based cancer therapy. In this review we focus on TRAIL gene therapy and various design strategies of TRAIL DNA delivery including non-viral vectors and cell-based TRAIL therapy. In order to sensitize the tumor cells to TRAIL-induced apoptosis, combination therapy of TRAIL DNA with other drugs by the codelivery methods for yielding a synergistic antitumor efficacy is summarized. The opportunities and challenges of TRAIL-based gene delivery and therapy are discussed.

Boosting Cancer Therapy with Organelle-Targeted Nanomaterials

The ultimate goal of cancer therapy is to eliminate malignant tumors while causing no damage to normal tissues. In the past decades, numerous nanoagents have been employed for cancer treatment because of their unique properties over traditional molecular drugs. However, lack of selectivity and unwanted therapeutic outcomes have severely limited the therapeutic index of traditional nanodrugs. Recently, a series of nanomaterials that can accumulate in specific organelles (nucleus, mitochondrion, endoplasmic reticulum, lysosome, Golgi apparatus) within cancer cells have received increasing interest. These rationally designed nanoagents can either directly destroy the subcellular structures or effectively deliver drugs into the proper targets, which can further activate certain cell death pathways, enabling them to boost the therapeutic efficiency, lower drug dosage, reduce side effects, avoid multidrug resistance, and prevent recurrence. In this Review, the design principles, targeting strategies, therapeutic mechanisms, current challenges, and potential future directions of organelle-targeted nanomaterials will be introduced.

Molecular Engineering of Functional Nucleic Acid Nanomaterials toward In Vivo Applications

Recent advances in nanotechnology and engineering have generated many nanomaterials with unique physical and chemical properties. Over the past decade, numerous nanomaterials are introduced into many research areas, such as sensors for environmental monitoring, food safety, point-of-care diagnostics, and as transducers for solar energy transfer. Meanwhile, functional nucleic acids (FNAs), including nucleic acid enzymes, aptamers, and aptazymes, have attracted major attention from the biomedical community due to their unique target recognition and catalytic properties. Benefiting from the recent progress of molecular engineering strategies, the physicochemical properties of nanomaterials are endowed by the target recognition and catalytic activity of FNAs in the presence of a target analyte, resulting in numerous smart nanoprobes for diverse applications including intracellular imaging, drug delivery, in vivo imaging, and tumor therapy. This progress report focuses on the recent advances in designing and engineering FNA-based nanomaterials, highlighting the functional outcomes toward in vivo applications. The challenges and opportunities for the future translation of FNA-based nanomaterials into clinical applications are also discussed.

Parallel multi-parameter study of PEI-functionalized gold nanoparticle synthesis for bio-medical applications: part 1-a critical assessment of methodology, properties, and stability

Cationic polyethyleneimine (PEI)-conjugated gold nanoparticles (AuNPs) that are chemically and physically stable under physiological conditions are an ideal candidate for certain bio-medical applications, in particular DNA transfection. However, the issue remains in reproducibly generating uniform stable species, which can cause the inadequate characterization of the resulting product under relevant conditions and timepoints. The principal objective of the present study was to develop an optimized and reproducible synthetic route for preparing stable PEI-conjugated AuNPs (Au-PEIs). To achieve this objective, a parallel multi-parametric approach involving a total of 96 reaction studies evaluated the importance of 6 key factors: PEI molar mass, PEI structure, molar ratio of PEI/Au, concentration of reaction mixtures, reaction temperature, and reaction time. Application of optimized conditions exhibited narrow size distributions with characteristic surface plasmon resonance absorption and positive surface charge. The optimized Au-PEI product generated by this study exhibits exceptional stability under a physiological isotonic medium (phosphate-buffered saline) over 48 h and shelf-life in ambient condition without any significant change or sedimentation for at least 6 months. Furthermore, the optimized Au-PEI product was highly reproducible. Contributions from individual factors were elucidated using a broad and orthogonal characterization suite examining size and size distribution, optical absorbance, morphological transformation (agglomeration/aggregation), surface functionalities, and stability. Overall, this comprehensive multi-parametric investigation, supported by thorough characterization and rigorous testing, provides a robust foundation for the nanomedicine research community to better synthesize nanomaterials for biomedical use.

Synthesis of an ethyleneimine/tetrahedral DNA nanostructure complex and its potential application as a multi-functional delivery vehicle

Nowadays, DNA nanostructures are extensively researched for their biocompatibility, editable functionality, and structural stability. Tetrahedral DNA nanostructures (TDNs), widely known for their membrane permeability, are regarded as potential candidates for drug delivery. However, the stability and membrane permeability of TDNs call for further enhancement if in vivo usage is ascribed. To overcome the drawbacks of TDNs, ethylene imine (PEI, 25 kDa, branched)-a classic cationic polymer in the field of gene delivery-was applied. Via a facile one-pot synthesis method, a PEI/TDNs complex was formed. Subsequently, a DNase protection assay, a cytotoxicity assay, endocytosis-related experiments, and lysosome staining were performed to examine the potential of PEI/TDNs as a delivery vehicle. The combination of PEI and TDNs not only overcame the drawbacks of each substance but also retained their individual merits. Traditionally, drug-delivery vehicles that enable enhanced cell entry and lysosome escape are often compromised by their toxicity and poor multifunctionality. We believe this novel PEI/TDNs complex with enhanced systemic stability, biocompatibility, cell-entry ability, and lysosome-escape ability and unsurpassed editable functionality could be a powerful tool as a multi-functional delivery vehicle in targeted drug delivery, in vivo imaging, and other related fields.

Synthesis, characterization and evaluation of transfection efficiency of dexamethasone conjugated poly(propyleneimine) nanocarriers for gene delivery#. PHARMACEUTICAL BIOLOGY 2018;56:519-527. [PMID: 30270694 PMCID: PMC6171438 DOI: 10.1080/13880209.2018.1517183]

CONTEXT

Polypropylenimine (PPI), a cationic dendrimer with defined structure and positive surface charge, is a potent non-viral vector. Dexamethasone (Dexa) conveys to the nucleus through interaction with its intracellular receptor.

OBJECTIVE

This study develops efficient and non-toxic gene carriers through conjugation of Dexa at various percentages (5, 10 and 20%) to the fourth and the fifth generation PPIs (PPIG4s and PPIG5s).

MATERIALS AND METHODS

The 21-OH group of Dexa (0.536 mmol) was modified with methanesulfonyl chloride (0.644 mmol) to activate it (Dexa-mesylate), and then it was conjugated to PPIs using Traut's reagent. After dialysis (48 h) and lyophilization, the physicochemical characteristics of products (PPI-Dexa) including zeta potential, size, buffering capacity and DNA condensing capability were investigated and compared with unmodified PPIs. Moreover, the cytotoxicity and transfection activity of the Dexa-modified PPIs were assessed using Neuro2A cells.

RESULTS

Transfection of PPIG4 was close to PEI 25 kDa. Although the addition of Dexa to PPIG4s did not improve their transfection, their cytotoxicity was improved; especially in the carrier to DNA weight ratios (C/P) of one and two. The Dexa conjugation to PPIG5s enhanced their transfection at C/P ratio of one in both 5% (1.3-fold) and 10% (1.6-fold) Dexa grafting, of which the best result was observed in PPIG5-Dexa 10% at C/P ratio of one.

DISCUSSION AND CONCLUSIONS

The modification of PPIs with Dexa is a promising approach to improve their cytotoxicity and transfection. The higher optimization of physicochemical characteristics, the better cell transfection and toxicity will be achieved.

Bifunctionally engineered polyethylenimines as efficient DNA carriers and antibacterials against resistant pathogens

In this study, we have designed and developed two series of bifunctional conjugates by tethering polyethylenimine with streptomycin. By varying the amount of streptomycin, conjugates, polyethylenimine-streptomycin, have been synthesized and characterized spectroscopically. Gel electrophoresis assay revealed a slight decrease in the cationic charge density on the conjugates as these retarded the mobility of pDNA at higher w/w ratios. Further, transfection studies showed that both the series of conjugates transfected the mammalian cells efficiently with low-molecular weight polyethylenimine-streptomycin conjugates were more competent (∼9-fold enhancement with respect to native bPEI) exhibiting high cell viability too. Besides, both the series of conjugates displayed excellent antibacterial activity on pathogenic bacteria, even better than native streptomycin on resistant strains. Altogether, these results ensure the promising potential of the projected bifunctional conjugates as safe and efficient gene delivery vectors as well as antibacterials for future biomedical applications.

A two-stage assembly with PEI induced emission enhancement of Au-AgNCs@AMP and the intrinsic mechanism

Recently, aggregation-induced emission (AIE) properties have been revealed for some metal nanoclusters (NCs), providing a new approach to improve the quantum yields (QY). In the present study, a two-stage assembly was carried out between adenosine monophosphate capped bimetallic nanoclusters of gold and silver (Au-AgNCs@AMP) and polyethylenimine (PEI), in which the QY was improved from 8.64% to 25.02%, showing obvious assembly induced emission enhancement (AIEE) properties. The intrinsic mechanisms of the assembly and emission enhancement in two stages were studied in depth, which indicated that the electrostatic interaction between the phosphate group in AMP and the amino group in PEI restricted the intramolecular vibration and rotation of capping ligands, and reduced the non-radiative relaxation of the corresponding excited states in stage I; in stage II, the micellization of PEI at high concentration pushed the NCs into a less polar environment and greatly enhanced the metal-metal interaction between them, which facilitated the excited state relaxation dynamics via a radiative pathway. Therefore, the luminescence enhancement depended on the assembly process in two stages directly. The present study is beneficial to understand the AIEE mechanism and the design principles, which will expand the applications of metal NCs.

Fluorescent Carbon Quantum Dots with Intrinsic Nucleolus-Targeting Capability for Nucleolus Imaging and Enhanced Cytosolic and Nuclear Drug Delivery

Nucleolus tracking and nucleus-targeted photodynamic therapy are attracting increasing attention due to the importance of nucleolus and the sensitivity of nucleus to various therapeutic stimuli. Herein, a new class of multifunctional fluorescent carbon quantum dots (or carbon dots, CDs) synthesized via the one-pot hydrothermal reaction of m-phenylenediamine and l-cysteine was reported to effectively target nucleolus. The as-prepared CDs possess superior properties, such as low-cost and facile synthesis, good water dispersibility, various surface groups for further modifications, prominent photostability, excellent compatibility, and rapid/convenient/wash-free staining procedures. Besides, as compared with SYTO RNASelect (a commonly used commercial dye for nucleolus imaging) that can only image nucleolus in fixed cells, the CDs can realize high-quality nucleolus imaging in not only fixed cells but also living cells, allowing the real-time tracking of nucleolus-related biological behaviors. Furthermore, after conjugating with protoporphyrin IX (PpIX), a commonly used photosensitizer, the resultant CD-PpIX nanomissiles showed remarkably increased cellular uptake and nucleus-targeting properties and achieved greatly enhanced phototherapeutic efficiency because the nuclei show poor tolerance to reactive oxygen species produced during the photodynamic therapy. The in vivo experiments revealed that the negatively charged CD-PpIX nanomissiles could rapidly and specifically target a tumor site after intravenous injection and cause efficient tumor ablation with no toxic side effects after laser irradiation. It is believed that the present CD-based nanosystem will hold great potential in nucleolus imaging and nucleus-targeted drug delivery and cancer therapy.

Photoinduced Rapid Transformation from Au Nanoagglomerates to Drug-Conjugated Au Nanovesicles

Gold (Au) agglomerates (AGs) are reassembled using Triton X-100 (T) and doxorubicin (D) dissolved in ethanol under 185 nm photoirradiation to form TAuD nanovesicles (NVs) under ambient gas flow conditions. The positively charged Au particles are then electrostatically conjugated with the anionic chains of TD components via a flowing drop (FD) reaction. Photoirradiation of the droplets in a tubular reactor continues the photophysicochemical reactions, resulting in the reassembly of Au AGs and TD into TAuD NVs. The fabricated NVs are electrostatically collected onto a polished aluminum rod in a single-pass configuration. The dispersion of NVs is employed for bioassays to confirm uptake by cells and accumulation in tumors. The chemo-photothermal activity is determined both in vitro and in vivo. Different combinations of components are also used to fabricate NVs using the FD reaction, and these NVs are suitable for gene delivery as well. This newly designed gaseous single-pass process results in the reassembly of Au AGs for incorporation with TD without the need of batch wet chemical reactions, modifications, separations, or purifications. Thus, this process offers an efficient platform for preparing biofunctional Au nanostructures that requires neither complex physicochemical steps nor special storage techniques.

Nanoparticles for Immune Cytokine TRAIL-Based Cancer Therapy

The immune cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has received significant attention as a cancer therapeutic due to its ability to selectively trigger cancer cell apoptosis without causing toxicity in vivo. While TRAIL has demonstrated significant promise in preclinical studies in mice as a cancer therapeutic, challenges including poor circulation half-life, inefficient delivery to target sites, and TRAIL resistance have hindered clinical translation. Recent advances in drug delivery, materials science, and nanotechnology are now being exploited to develop next-generation nanoparticle platforms to overcome barriers to TRAIL therapeutic delivery. Here, we review the design and implementation of nanoparticles to enhance TRAIL-based cancer therapy. The platforms we discuss are diverse in their approaches to the delivery problem and provide valuable insight into guiding the design of future nanoparticle-based TRAIL cancer therapeutics to potentially enable future translation into the clinic.

pH and molecular weight dependence of auric acid reduction by polyethylenimine and the gene transfection efficiency of cationic gold nanoparticles thereof

Small, cationic gold nanoparticles (GNPs) are produced by the direct reduction of auric acid in a non-reducing solvent, water, with branched polyethylenimine (bPEI) in a broad pH range (3.0–9.0).

Core/Shell Gene Carriers with Different Lengths of PLGA Chains to Transfect Endothelial Cells

In order to improve the transfection efficiency and reduce the cytotoxicity of gene carriers, many strategies have been used to develop novel gene carriers. In this study, five complex micelles (MSP(2 k), MSP(4 k), MSP(6 k), MSP(8 k), and MSP(10 k)) were prepared from methoxy-poly(ethylene glycol)-b-poly(d,l-lactide-co-glycolide) (mPEG-b-PLGA) and sorbitol-poly(d,l-lactide-co-glycolide)-graft-PEI (sorbitol-PLGA-g-PEI, where the designed molecular weights of PLGA chains were 2 kDa, 4 kDa, 6 kDa, 8 kDa, and 10 kDa, respectively) copolymers by a self-assembly method, and the mass ratio of mPEG-b-PLGA to sorbitol-PLGA-g-PEI was 1/3. These complex micelles and their gene complexes had appropriate sizes and zeta potentials, and pEGFP-ZNF580 (pDNA) could be efficiently internalized into EA.hy926 cells by their gene complexes (MSP(2 k)/pDNA, MSP(4 k)/pDNA, MSP(6 k)/pDNA, MSP(8 k)/pDNA, and MSP(10 k)/pDNA). The MTT assay results demonstrated that the gene complexes had low cytotoxicity in vitro. When the hydrophobic PLGA chain increased above 6 kDa, the gene complexes showed higher performance than that prepared from short hydrophobic chains. Moreover, the relative ZNF580 protein expression levels in MSP(6 k)/pDNA, MSP(8 k)/pDNA, and MSP(10 k)/pDNA) groups were 79.6%, 71.2%, and 73%, respectively. These gene complexes could promote the transfection of endothelial cells, while providing important information and insight for the design of new and effective gene carriers to promote the proliferation and migration of endothelial cells.

Strategies in the design of gold nanoparticles for intracellular targeting: opportunities and challenges

With unique physicochemical properties, gold nanoparticles (Au NPs) have demonstrated their potential as drug carriers or therapeutic agents. Effective guidance of Au NPs into specific intracellular destinations becomes increasingly important as we strive to further improve the efficiency of drug delivery and modulate controllable cellular responses. In this review, we summarized recent advances in designing Au NPs with the capabilities of cellular penetration and internalization, endosomal escape, intracellular trafficking and subcellular localization via various approaches including physical injection, tuning the physiochemical parameters of Au NPs, and surface modification with targeting ligands. Strategies for delivering Au NPs to specific subcellular destinations including the nucleus, mitochondria, endoplasmic reticulum, lysosomes are also discussed. Moreover, current challenges associated with intracellular targeting of Au NPs are discussed with future perspectives proposed.

Nanocarriers for TRAIL delivery: driving TRAIL back on track for cancer therapy

Since its initial identification, tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has been shown to be capable of selectively inducing apoptosis in cancer cells. However, translation of the encouraging preclinical studies of this cytokine into the clinic has been restricted by its extremely short half-life, the presence of resistant cancer cell populations, and its inefficient in vivo delivery. Recently, there has been exceptional progress in developing novel formulations to increase the circulatory half-life of TRAIL and new combinations to treat cancers that are resistant to TRAIL. In particular, TRAIL-based nanotherapies offer the potential to improve the stability of TRAIL and prolong its half-life in plasma, to specifically deliver TRAIL to a particular target site, and to overcome resistance to TRAIL. The aim of this review is to provide an overview of the state-of-the art drug delivery systems that are currently being tested or developed to improve the biological attributes of TRAIL-based therapies.

MDR in cancer: Addressing the underlying cellular alterations with the use of nanocarriers

Multidrug resistance (MDR) is associated with a wide range of pathological changes at different cellular and intracellular levels. Nanoparticles (NPs) have been extensively exploited as the carriers of MDR reversing payloads to resistant tumor cells. However, when properly formulated in terms of chemical composition and physicochemical properties, NPs can serve as beyond delivery systems and help overcome MDR even without carrying a load of chemosensitizers or MDR reversing molecular cargos. Whether serving as drug carriers or beyond, a wise design of the nanoparticulate systems to overcome the cellular and intracellular alterations underlying the resistance is imperative. Within the current review, we will initially discuss the cellular changes occurring in resistant cells and how such changes lead to chemotherapy failure and cancer cell survival. We will then focus on different mechanisms through which nanosystems with appropriate chemical composition and physicochemical properties can serve as MDR reversing units at different cellular and intracellular levels according to the changes that underlie the resistance. Finally, we will conclude by discussing logical grounds for a wise and rational design of MDR reversing nanoparticulate systems to improve the cancer therapeutic approaches.

Transdermal Gene Delivery by Functional Peptide-Conjugated Cationic Gold Nanoparticle Reverses the Progression and Metastasis of Cutaneous Melanoma

Permeability barrier imposed by stratum corneum makes an extreme challenge for the topical delivery of plasmid DNA (pDNA), which is widely used in gene therapy. Existing techniques to overcome the skin barrier for bio-macromolecules delivery rely on sophisticated mechanical devices. It is still a big challenge to treat the skin cancer, for example, melanoma, that initiates in the dermal layer by topical gene therapy. To facilitate the skin penetration of pDNA deeply into the melanoma tissues, we here present a cell-penetrating peptide and cationic poly(ethyleneimine) conjugated gold nanoparticle (AuPT) that can compact the pDNAs into cationic nanocomplexes and penetrate through the intact stratum corneum without any additional enhancement used. Moreover, the AuPT is highly efficient in stimulating the intracellular uptake and nuclear targeting of the pDNAs in cells, which guarantees the effective transfection. This study provides evidence that penetrating peptide conjugated cationic gold nanoparticle offers a promising vehicle for both the skin penetration and transfection of pDNAs, possessing great potential in topical gene therapy.

NIR-Responsive Polycationic Gatekeeper-Cloaked Hetero-Nanoparticles for Multimodal Imaging-Guided Triple-Combination Therapy of Cancer

Responsive multifunctional organic/inorganic nanohybrids are promising for effective and precise imaging-guided therapy of cancer. In this work, a near-infrared (NIR)-triggered multifunctional nanoplatform comprising Au nanorods (Au NRs), mesoporous silica, quantum dots (QDs), and two-armed ethanolamine-modified poly(glycidyl methacrylate) with cyclodextrin cores (denoted as CD-PGEA) has been successfully fabricated for multimodal imaging-guided triple-combination treatment of cancer. A hierarchical hetero-structure is first constructed via integration of Au NRs with QDs through a mesoporous silica intermediate layer. The X-ray opacity and photoacoustic (PA) property of Au NRs are utilized for tomography (CT) and PA imaging, and the imaging sensitivity is further enhanced by the fluorescent QDs. The mesoporous feature of silica allows the loading of a typical antitumor drug, doxorubicin (DOX), which are sealed by the polycationic gatekeepers, low toxic hydroxyl-rich CD-PGEA/pDNA complexes, realizing the co-delivery of drug and gene. The photothermal effect of Au NRs is utilized for photothermal therapy (PTT). More interestingly, such photothermal effect also induces a cascade of NIR-triggered release of DOX through the facilitated detachment of CD-PGEA gatekeepers for controlled chemotherapy. The resultant chemotherapy and gene therapy for glioma tumors are complementary for the efficiency of PTT. This work presents a novel responsive multifunctional imaging-guided therapy platform, which combines fluorescent/PA/CT imaging and gene/chemo/photothermal therapy into one nanostructure.

New Frontiers in Promoting TRAIL-Mediated Cell Death: Focus on Natural Sensitizers, miRNAs, and Nanotechnological Advancements

Cancer is a multifaceted and genomically complex disease, and rapidly emerging scientific evidence is emphasizing on intra-tumor heterogeneity within subpopulations of tumor cells and rapidly developing resistance against different molecular therapeutics. There is an overwhelmingly increasing list of agents currently being tested for efficacy against cancer. In accordance with the concept that therapeutic agents must have fewer off target effects and considerable efficacy, TRAIL has emerged as one among the most deeply investigated proteins reportedly involved in differential killing of tumor cells. Considerable killing activity of TRAIL against different cancers advocated its entry into clinical trials. However, data obtained through preclinical and cell culture studies are deepening our understanding of wide-ranging mechanisms which induce resistance against TRAIL-based therapeutics. These include downregulation of death receptors, overexpression of oncogenes, inactivation of tumor suppressor genes, imbalance of pro- and anti-apoptotic proteins, and inactivation of intrinsic and extrinsic pathways. Substantial fraction of information has been added into existing pool of knowledge related to TRAIL biology and recently accumulating evidence is adding new layers to regulation of TRAIL-induced apoptosis. Certain hints have emerged underscoring miR135a-3p- and miR-143-mediated regulation of TRAIL-induced apoptosis, and natural agents have shown remarkable efficacy in improving TRAIL-based therapeutics by increasing expression of tumor suppressor miRNAs. In this review, we summarize most recent breakthroughs related to naturopathy and strategies to nanotechnologically deliver TRAIL to the target site in xenografted mice. We also set spotlight on positive and negative regulators of TRAIL-mediated signaling. Comprehensive knowledge of genetics and proteomics of TRAIL-based signaling network obtained from cancer patients of different populations will be helpful in getting a step closer to personalized medicine.

Polyethyleneimine-Coated Gold Nanoparticles: Straightforward Preparation of Efficient DNA Delivery Nanocarriers

A novel one-pot method for the synthesis of polyethyleneimine (PEI)-coated gold nanoparticles (AuPEI-NPs) that combines the reductant-stabilizer properties of PEI with microwave irradiation starting from hydrogen tetrachloroaurate acid (HAuCl₄ ) and branched PEI 25 kDa (b25kPEI) was explored. The method was straightforward, green, and low costing, for which the Au/PEI ratio (1:1 to 1:128 w/w) was a key parameter to modulate their capabilities as DNA delivery nanocarriers. Transfection assays in CHO-k1 cells demonstrated that AuPEI-NPs with 1:16 and 1:32 w/w ratios behaved as effective DNA gene vectors with improved transfection efficiencies (twofold) and significantly lower toxicity than unmodified b25kPEI and Lipofectamine 2000. The transfection mediated by these AuPEI-NP-DNA polyplexes preferentially used the caveolae-mediated route for intracellular internalization, as shown by studies performed by using specific internalization inhibitors as well as colocalization with markers of clathrin- and caveolae-dependent pathways. The AuPEI-NP polyplexes preferentially used the more efficient caveolae internalization pathway to promote transfection, a fact that supports their higher transfection efficiency relative to that of Lipofectamine 2000. In addition, intracellular trafficking of the AuPEI-NPs was studied by transmission electron microscopy.

Vectorization of Nucleic Acids for Therapeutic Approach: Tutorial Review

Oligonucleotides present a high therapeutic potential for a wide variety of diseases. However, their clinical development is limited by their degradation by nucleases and their poor blood circulation time. Depending on the administration mode and the cellular target, these macromolecules will have to cross the vascular endothelium, to diffuse through the extracellular matrix, to be transported through the cell membrane, and finally to reach the cytoplasm. To overcome these physiological barriers, many strategies have been developed. Here, we review different methods of DNA vectorization, discuss limitations and advantages of the various vectors, and provide new perspectives for future development.

How successful is nuclear targeting by nanocarriers?

The nucleus is ultimately the final target for many therapeutics treating various disorders including cancers, heart dysfunction and brain disorders. Owing to their specialized cell uptake and trafficking mechanisms, nanoparticles (NPs) allow drug targeting where degradation sensitive therapeutics could be delivered to their target tissues and cell in active form and sufficient concentration. However, it has recently become increasingly obvious that cytosolic internalization of a drug molecule does not entail its interaction with its subcellular target and hence careful nanoparticle design and optimization is required to enable nuclear targeting. This review, discusses the barriers to NP nuclear delivery; crossing the cell membrane, endo/lysosomal escape, cytoplasmic trafficking and finally nuclear entry focusing on how NP synthesis and modification could allow for bypassing each of the aforementioned barriers and successfully reaching the nucleus. Examples of nuclear targeted NPs are also discussed, stressing on the critical aspects of nuclear targeting and pointing out how the disease state might change the normal NP path and how such change could be exploited to increase efficiency of nuclear targeting. Finally, the criteria set for the evaluation of nanocarriers for nuclear delivery are discussed highlighting that quantitative rather than qualitative evaluation is required to evaluate how successful nanocarriers for nuclear delivery are, particularly with regards to the amount of drug delivered and released in the nucleus.

Tumor therapy: targeted drug delivery systems

The review highlights the main targeted drug delivery systems for tumor therapy, including the targeting sites, strategies, mechanisms and preclinical/clinical trials.

Investigation of the fluorescence quenching behavior of PEI-doped silica nanoparticles and its applications

A simple and feasible method for overcoming the fluorescence quenching effect of PEI on fluorophores (eosin Y was chosen as the model dye) was designed for the first time.

Cancer-Cell-Specific Nuclear-Targeted Drug Delivery by Dual-Ligand-Modified Mesoporous Silica Nanoparticles

Mesoporous silica nanoparticles are modified with dual targeting ligands, i.e., folic acid and dexamethasone, to construct a cancer-cell-specific nuclear-targeted delivery system. The resulting nanocarriers can not only enhance the inhibition efficacy of doxorubicin on Hela cells through active nucleus accumulation but also reduce toxic side effects on noncancer cells though receptor-mediated selective cellular uptake.

Iron Oxide Nanoparticles Coated with a Phosphorothioate Oligonucleotide and a Cationic Peptide: Exploring Four Different Ways of Surface Functionalization

The superparamagnetic iron oxide nanoparticles (SPIONs) have great potential in therapeutic and diagnostic applications. Due to their superparamagnetic behavior, they are used clinically as a Magnetic Resonance Imaging (MRI) contrast agent. Iron oxide nanoparticles are also recognized todays as smart drug-delivery systems. However, to increase their specificity, it is essential to functionalize them with a molecule that effectively targets a specific area of the body. Among the molecules that can fulfill this role, peptides are excellent candidates. Oligonucleotides are recognized as potential drugs for various diseases but suffer from poor uptake and intracellular degradation. In this work, we explore four different strategies, based on the electrostatic interactions between the different partners, to functionalize the surface of SPIONs with a phosphorothioate oligonucleotide (ODN) and a cationic peptide labeled with a fluorophore. The internalization of the nanoparticles has been evaluated in vitro on RAW 264.7 cells. Among these strategies, the "«one-step assembly»", i.e., the direct complexation of oligonucleotides and peptides on iron oxide nanoparticles, provides the best way of coating for the internalization of the nanocomplexes.

CREDVW-Linked Polymeric Micelles As a Targeting Gene Transfer Vector for Selective Transfection and Proliferation of Endothelial Cells

Nowadays, gene transfer technology has been widely used to promote endothelialization of artificial vascular grafts. However, the lack of gene vectors with low cytotoxicity and targeting function still remains a pressing challenge. Herein, polyethylenimine (PEI, 1.8 kDa or 10 kDa) was conjugated to an amphiphilic and biodegradable diblock copolymer poly(ethylene glycol)-b-poly(lactide-co-glycolide) (mPEG-b-PLGA) to prepare mPEG-b-PLGA-g-PEI copolymers with the aim to develop gene vectors with low cytotoxicity while high transfection efficiency. The micelles were prepared from mPEG-b-PLGA-g-PEI copolymers by self-assembly method. Furthermore, Cys-Arg-Glu-Asp-Val-Trp (CREDVW) peptide was linked to micelle surface to enable the micelles with special recognition for endothelial cells (ECs). In addition, pEGFP-ZNF580 plasmids were condensed into these CREDVW-linked micelles to enhance the proliferation of ECs. These CREDVW-linked micelle/pEGFP-ZNF580 complexes exhibited low cytotoxicity by MTT assay. The cell transfection results demonstrated that pEGFP-ZNF580 could be transferred into ECs efficiently by these micelles. The results of Western blot analysis showed that the relative ZNF580 protein level in transfected ECs increased to 76.9%. The rapid migration of transfected ECs can be verified by wound healing assay. These results indicated that CREDVW-linked micelles could be a suitable gene transfer vector with low cytotoxicity and high transfection efficiency, which has great potential for rapid endothelialization of artificial blood vessels.

Polyethylenimine coated plasmid DNA-surfactant complexes as potential gene delivery systems

Nanometer scaled particles have been prepared from strong association between plasmid DNA (pcDNA3-FLAG-p53) and oppositely charged surfactants. Although these particles present suitable properties for gene delivery purposes, their cytotoxicity could compromise their use in gene therapy applications. To ensure biocompatibility of this potential gene delivery system, the nanoparticles were coated with polyethylenimine (PEI) with various molar ratios of PEI nitrogen to plasmid DNA phosphate groups. This led to a drastic increase in the cell viability of the particles, and in addition particle characteristics such as size, surface charge and loading efficiency, have also been enhanced as a result of the PEI coating process. The dissolution or swelling/deswelling behaviour displayed by these particulate vehicles could be tailored and monitored in time, to promote the controlled and sustained release of plasmid DNA. Moreover, we show that both the surfactant alkyl chain length and the ratio of nitrogen to phosphate groups are important parameters for controlling the plasmid DNA release. Overall, the developed plasmid DNA carriers have the potential as a new nanoplatform to be further explored for advances in the gene therapy field.

Polycation-functionalized gold nanoparticles with different morphologies for superior gene transfection

Favorable physical and chemical properties endow Au nanoparticles (Au NPs) with various biomedical applications. After appropriate surface functionalization, Au NPs could construct promising drug/gene carriers with multiple functions. There is now ample evidence that physicochemical properties, such as size, shape, and surface chemistry, can dramatically influence the behaviors of Au NPs in biological systems. Investigation of these parameters could be fundamentally important for the application of Au NPs as drug/gene carriers. In this work, we designed a series of novel gene carriers employing polycation-functionalized Au NPs with five different morphologies (including Au nanospheres, Au nano-octahedra, arrow-headed Au nanorods, and Au nanorods with different aspect ratios). The effects of the particle size and shape of these different carriers on gene transfection were investigated in detail. The morphology of Au NPs is demonstrated to play an important role in gene transfection. The most efficient gene carriers are those fabricated with arrow-headed Au nanorods. Au nanosphere-based carriers exhibit the poorest performance in gene transfection. In addition, Au nanorods with smaller aspect ratios perform better than longer ones. These results may provide new avenues to develop promising gene carriers and gain useful information on the interaction of Au NPs with biological systems.