Preparation and Characterization of Cationic PLA-PEG Nanoparticles for Delivery of Plasmid DNA

Nanotechnology-based non-viral vectors for gene delivery in cardiovascular diseases

Gene therapy is a technique that rectifies defective or abnormal genes by introducing exogenous genes into target cells to cure the disease. Although gene therapy has gained some accomplishment for the diagnosis and therapy of inherited or acquired cardiovascular diseases, how to efficiently and specifically deliver targeted genes to the lesion sites without being cleared by the blood system remains challenging. Based on nanotechnology development, the non-viral vectors provide a promising strategy for overcoming the difficulties in gene therapy. At present, according to the physicochemical properties, nanotechnology-based non-viral vectors include polymers, liposomes, lipid nanoparticles, and inorganic nanoparticles. Non-viral vectors have an advantage in safety, efficiency, and easy production, possessing potential clinical application value when compared with viral vectors. Therefore, we summarized recent research progress of gene therapy for cardiovascular diseases based on commonly used non-viral vectors, hopefully providing guidance and orientation for future relevant research.

Design and synthesis of multi-targeted nanoparticles for gene delivery to breast cancer tissues

Biocompatibility of nanoparticles is the most essential factor in their use in clinical applications. In this study, hyperbranched spermine (HS), hyperbranched spermine-polyethylene glycol-folic acid (HSPF), and hyperbranched spermine-polyethylene glycol-glucose (HSPG) were synthesized for DNA protection and gene delivery to breast cancer cells. The synthesis of HSPG and HSPF was confirmed using proton nuclear magnetic resonance (H-NMR), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) spectroscopy. The HS/DNA, HSPF/DNA, HSPG/DNA, and hyperbranched spermine-polyethylene glycol-folic acid/glucose/DNA (HSPFG/DNA) nanoparticles were prepared by combining different concentrations of HS, HSPF, and HSPG with the same amount of DNA. The ability of HS, HSPF, and HSPG to interact with DNA and protect it against plasm digestion was evaluated using agarose gel. Moreover, in vivo and in vitro biocompatibility of HSPF/DNA, HSPG/DNA, and HSPFG/DNA was investigated using MTT assay and calculating weight change and survival ratio of BALB/c mice, respectively. The results of agarose gel electrophoresis showed that HS, HSPF, and HSPG have the high ability to neutralize the negative charge of DNA and protect it against plasma degradation. The results of in vivo cytotoxicity assay revealed that the HSPF/DNA, HSPG/DNA, and HSPFG/DNA nanoparticles have good biocompatibility on female BALB/c mice. In vitro and in vivo transfection assays revealed that functionalization of the surface of HS using polyethylene glycol-folic acid (HSPF) and polyethylene glycol-glucose (HSPG) significantly increases gene delivery efficiency in vitro and in vivo. These results also showed that gene transfer using both HSPF and HSPG copolymers increases gene transfer efficiency compared to when only one of them is used. The HSPFG/DNA nanoparticles have a high potential for use in therapeutic applications because of their excellent biocompatibility and high gene transfer efficiency to breast cancer tissue.

Peptides to Overcome the Limitations of Current Anticancer and Antimicrobial Nanotherapies

Biomedical research devotes a huge effort to the development of efficient non-viral nanovectors (NV) to improve the effectiveness of standard therapies. NVs should be stable, sustainable and biocompatible and enable controlled and targeted delivery of drugs. With the aim to foster the advancements of such devices, this review reports some recent results applicable to treat two types of pathologies, cancer and microbial infections, aiming to provide guidance in the overall design of personalized nanomedicines and highlight the key role played by peptides in this field. Additionally, future challenges and potential perspectives are illustrated, in the hope of accelerating the translational advances of nanomedicine.

Synthesis and Characterization of Poly (β-amino Ester) and Applied PEGylated and Non-PEGylated Poly (β-amino ester)/Plasmid DNA Nanoparticles for Efficient Gene Delivery

Polymer-based nanocarriers require extensive knowledge of their chemistries to learn functionalization strategies and understand the nature of interactions that they establish with biological entities. In this research, the poly (β-amino ester) (PβAE-447) was synthesized and characterized, aimed to identify the influence of some key parameters in the formulation process. Initially; PβAE-447 was characterized for aqueous solubility, swelling capacity, proton buffering ability, and cytotoxicity study before nanoparticles formulation. Interestingly, the polymer-supported higher cell viability than the Polyethylenimine (PEI) at 100 μg/ml. PβAE-447 complexed with GFP encoded plasmid DNA (pGFP) generated nanocarriers of 184 nm hydrodynamic radius (+7.42 mV Zeta potential) for cell transfection. Transfection assays performed with PEGylated and lyophilized PβAE-447/pDNA complexes on HEK-293, BEAS-2B, and A549 cell lines showed better transfection than PEI. The outcomes toward A549 cells (above 66%) showed the highest transfection efficiency compared to the other cell lines. Altogether, these results suggested that characterizing physicochemical properties pave the way to design a new generation of PβAE-447 for gene delivery.

Tween® Preserves Enzyme Activity and Stability in PLGA Nanoparticles

Enzymes, as natural and potentially long-term treatment options, have become one of the most sought-after pharmaceutical molecules to be delivered with nanoparticles (NPs); however, their instability during formulation often leads to underwhelming results. Various molecules, including the Tween^® polysorbate series, have demonstrated enzyme activity protection but are often used uncontrolled without optimization. Here, poly(lactic-co-glycolic) acid (PLGA) NPs loaded with β-glucosidase (β-Glu) solutions containing Tween^® 20, 60, or 80 were compared. Mixing the enzyme with Tween^® pre-formulation had no effect on particle size or physical characteristics, but increased the amount of enzyme loaded. More importantly, NPs made with Tween^® 20:enzyme solutions maintained significantly higher enzyme activity. Therefore, Tween^® 20:enzyme solutions ranging from 60:1 to 2419:1 mol:mol were further analyzed. Isothermal titration calorimetry analysis demonstrated low affinity and unquantifiable binding between Tween^® 20 and β-Glu. Incorporating these solutions in NPs showed no effect on size, zeta potential, or morphology. The amount of enzyme and Tween^® 20 in the NPs was constant for all samples, but a trend towards higher activity with higher molar rapports of Tween^® 20:β-Glu was observed. Finally, a burst release from NPs in the first hour with Tween^®:β-Glu solutions was the same as free enzyme, but the enzyme remained active longer in solution. These results highlight the importance of stabilizers during NP formulation and how optimizing their use to stabilize an enzyme can help researchers design more efficient and effective enzyme loaded NPs.

Niosomes-based gene delivery systems for effective transfection of human mesenchymal stem cells

Gene transfer to mesenchymal stem cells (MSCs) has arisen as a powerful approach to increase the therapeutic potential of this effective cell population. Over recent years, niosomes have emerged as self-assembled carriers with promising performance for gene delivery. The aim of our work was to develop effective niosomes-based DNA delivery platforms for targeting MSCs. Niosomes based on 1,2-di-O-octadecenyl-3-trimethylammonium propane (DOTMA; 0, 7 or 15%) as cationic lipid, cholesterol as helper lipid, and polysorbate 60 as non-ionic surfactant, were prepared using a reverse phase evaporation technique. Niosomes dispersions (filtered or not) and their corresponding nioplexes with a lacZ plasmid were characterized in terms of size, charge, protection, and complexation abilities. DOTMA concentration had a large influence on the physicochemical properties of resulting nioplexes. Transfection efficiency and cytotoxic profiles were assessed in two immortalized cell lines of MSCs. Niosomes formulated with 15% DOTMA provided the highest values of β-galactosidase activity, being similar to those achieved with Lipofectamine®, but showed less cytotoxicity. Filtration of niosomes dispersions before adding to the cells resulted in a loss of their biological activities. Storage of niosomes formulations (for 30 days at room temperature) caused minor modification of their physicochemical properties but also attenuated the transfection capability of the nioplexes. Differently, addition of the lysosomotropic agent sucrose into the culture medium during transfection or to the formulation itself improved the transfection performance of non-filtered niosomes. Indeed, steam heat-sterilized niosomes prepared in sucrose medium demonstrated transfection capability.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

SP94-Targeted Triblock Copolymer Nanoparticle Delivers Thymidine Kinase-p53-Nitroreductase Triple Therapeutic Gene and Restores Anticancer Function against Hepatocellular Carcinoma in Vivo

Gene-directed enzyme-prodrug therapy (GDEPT) is a promising approach for cancer therapy, but it suffers from poor targeted delivery in vivo. Polyethylenimine (PEI) is a cationic polymer efficient in delivering negatively charged nucleic acids across cell membranes; however, it is highly toxic in vivo. Hence, we efficiently reduced PEI toxicity without compromising its transfection efficiency by conjugating it with poly(d,l-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) as triblock copolymers through a multistep synthetic process. The synthesized nanoparticles showed efficient delivery of loaded nucleic acids to tumor cells in vitro and in vivo in mice. We used this nanoparticle to deliver a rationally engineered thymidine kinase (TK)-p53-nitroreductase (NTR) triple therapeutic gene against hepatocellular carcinoma (HCC), where p53 tumor suppressor gene is mutated in more than 85% of cancers. TK-p53-NTR triple gene therapy restores p53 function and potentiates cancer cell response to delivered prodrugs (ganciclovir (GCV) and CB1954). We used SP94 peptide-functionalized PLGA-PEG-PEI nanoparticles for the optimal delivery of TK-p53-NTR therapeutic gene in vivo. The nanoparticles prepared from the conjugated polymer showed high loading efficiency for the DNA and markedly enhanced TK-NTR-mediated gene therapy upon the simultaneous coexpression of p53 by the concurrent rescue of the endogenous apoptotic pathway in HCC cells of both p53-mutant and wild-type phenotypes in vitro. In vivo delivery of TK-p53-NTR genes by SP94-targeted PLGA-PEG-PEI NP in mice resulted in a strong expression of suicide genes selectively in tumors, and subsequent administration of GCV and CB1954 led to a decline in tumor growth, and established a superior therapeutic outcome against HCC. We demonstrate a highly efficient approach that exogenously supplements p53 to enable synergy with the outcome of TK-NTR suicide gene therapy against HCC.

Introduction of magnetic and supermagnetic nanoparticles in new approach of targeting drug delivery and cancer therapy application

In this article, the recent applications of different types of magnetic nanoparticles such as α-Fe₂O₃ (hematite), γ-Fe₂O₃ (maghemite), Fe₃O₄ (magnetite), hexagonal (MFe₁₂O₁₉), garnet (M₃Fe₅O₁₂) and spinel (MFe₂O₄), where M represents one or more bivalent transition metals (Mn, Fe, Co, Ni, Ba, Sr, Cu, and Zn), and different materials for coating the surface of magnetic nanoparticles like poly lactic acid (PLA), doxorubicin hydrophobic (DOX-HCL), paclitaxel (PTX), EPPT-FITC, oleic acid, tannin, 3-Aminopropyltriethoxysilane (APTES), multi-wall carbon nanotubes (CNTs), polyethylenimine (PEI) and polyarabic acid in drug delivery, biomedicine and treatment of cancer, specially chemotherapy, are reviewed. MNPs possess large surface area to volume ratios because of their nano-size, low surface charge at physiological pH and they aggregate easily in solution due to their essential magnetic nature. These materials are widely used in biology and medicine in many cases. One targeted delivery technique that has gained prominence in recent years is the use of magnetic nanoparticles. In these systems, therapeutic compounds are attached to biocompatible magnetic nanoparticles and magnetic fields generated outside the body are focused on specific targets in vivo. The fields capture the particle complex, resulting in enhanced delivery to the target site. Also, the application of brand new supermagnetic nanoparticles, like Ba,SrFe₁₂O₁₉, is considered and studied in this paper.

Safe Nanocomposite-Mediated Efficient Delivery of MicroRNA Plasmids for Autosomal Dominant Polycystic Kidney Disease (ADPKD) Therapy

There is currently no cure for gene mutation-caused autosomal dominant polycystic kidney disease (ADPKD). Over half of patients with ADPKD eventually develop kidney failure, requiring dialysis or kidney transplantation. Current treatment modalities for ADPKD focus on reducing morbidity and mortality from renal and extrarenal complications of the disease. MicroRNA has been shown to be useful in treating ADPKD. This study combines anti-miRNA plasmids and iron oxide/alginate nanoparticles for conjugation with antikidney antibodies. These nanocomposites can specifically target renal tubular cells, providing a potential treatment for ADPKD. Magnetic resonance imaging and in vivo imaging system results show effective targeting of renal cells. Anti-miRNA plasmids released from the nanocomposites inhibit cell proliferation and cyst formation in the PKD cellular and animal models. The results suggest the novel combination of the anti-miRNA plasmids and nanomaterials provides potential clinical implications for ADPKD treatment.

Preparation and Characterization of PLA-PEG-PLA/PEI/DNA Nanoparticles for Improvement of Transfection Efficiency and Controlled Release of DNA in Gene Delivery Systems

Tri-block poly (lactide) poly(ethylene glycol) poly(lactide) (PLA-PEG-PLA) copolymers are among the most attractive nano-carriers for gene delivery into mammalian cells, due to their biocompatibility and biodegradability properties. However, the low efficiency of the gene delivery by these copolymers is an obstacle to gene therapy. Here, we have investigated nanoparticles formulated using the polyethylenimine (PEI) associated with PLA-PEG-PLA copolymer for efficient DNA encapsulation and delivery. PLA-PEG-PLA/DNA and PLA-PEG-PLA/PEI/DNA nanoparticles with different concentrations of PEI were prepared by the double emulsion-solvent evaporation technique. PLA-PEG-PLA/PEI/DNA were characterized for particle size, zeta potential, morphology, biocompatibility, DNA protection, DNA release, and their ability for gene delivery into MCF-7 cells. We found that enhancing the mass ratio of PEI: (PLA-PEG-PLA) (w/w%) in the PLA-PEG-PLA/PEI/DNA nanoparticles results in an increase in particles size, zeta potential, encapsulation efficiency, and DNA release. The electrophoretic analysis confirmed that the PLA-PEG-PLA and PLA-PEG-PLA/PEI could protect DNA from ultrasound damage and nuclease degradation. MTT assay showed that the PLA-PEG-PLA/PEI/DNA had low cytotoxicity than PEI complexes. The potential of PLA-PEG-PLA/PEI/DNA nanoparticles with different concentrations of PEI as a non-viral gene delivery vector for transferring pEGFP-N1 to MCF-7 cells was examined by fluorescent microscopy and flow cytometry. The flow cytometry analysis revealed that by increasing the mass ratio of PEI: (PLA-PEG-PLA) (w/w%) in PLA-PEG-PLA/PEI/DNA nanoparticles, the efficiency of the gene delivery into MCF-7 cells was improved. The results also demonstrated that PLA-PEG-PLA/PEI/DNA nanoparticles in the serum medium improved the efficiency of gene delivery more than two-fold, compared to PEI/DNA complex.

The Chlamydia M278 Major Outer Membrane Peptide Encapsulated in the Poly(lactic acid)-Poly(ethylene glycol) Nanoparticulate Self-Adjuvanting Delivery System Protects Mice Against a Chlamydia muridarum Genital Tract Challenge by Stimulating Robust Systemic and Local Mucosal Immune Responses

Recently, we reported that our PPM chlamydial nanovaccine [a biodegradable co-polymeric PLA-PEG (poly(lactic acid)-poly(ethylene glycol))-encapsulated M278 peptide (derived from the major outer membrane protein (MOMP) of Chlamydia)] exploits the caveolin-mediated endocytosis pathway for endosomal processing and MHC class II presentation to immune-potentiate Chlamydia-specific CD4⁺ T-cell immune effector responses. In the present study, we employed the Chlamydia muridarum mouse infection model to evaluate the protective efficacy of PPM against a genital tract challenge. Our results show that mice immunized with PPM were significantly protected against a homologous genital tract challenge evidently by reduced vaginal bacterial loads. Protection of mice correlated with enhanced Chlamydia-specific adaptive immune responses predominated by IFN-γ along with CD4⁺ T-cells proliferation and their differentiation to CD4⁺ memory (CD44^high CD62L^high) and effector (CD44^high CD62L^low) T-cell phenotypes. We observed the elevation of M278- and MOMP-specific serum antibodies with high avidity in the ascending order IgG1 > IgG2b > IgG2a. A key finding was the elevated mucosal IgG1 and IgA antibody titers followed by an increase in MOMP-specific IgA after the challenge. The Th1/Th2 antibody titer ratios (IgG2a/IgG1 and IgG2b/IgG1) revealed that PPM evoked a Th2-directed response, which skewed to a Th1-dominated antibody response after the bacterial challenge of mice. In addition, PPM immune sera neutralized the infectivity of C. muridarum in McCoy cells, suggesting the triggering of functional neutralizing antibodies. Herein, we reveal for the first time that subcutaneous immunization with the self-adjuvanting biodegradable co-polymeric PPM nanovaccine immune-potentiated robust CD4⁺ T cell-mediated immune effector responses; a mixed Th1 and Th2 antibody response and local mucosal IgA to protect mice against a chlamydial genital tract challenge.

Antimicrobial Photodynamic Therapy Mediated by Curcumin-Loaded Polymeric Nanoparticles in a Murine Model of Oral Candidiasis

Antimicrobial photodynamic therapy (aPDT) has been proposed as an alternative method for oral candidiasis (OC), while nanocarriers have been used to improve the water solubility of curcumin (CUR). The aim of this study is to encapsulate CUR in polymeric nanoparticles (NPs) and to evaluate its photodynamic effects on a murine model of OC. Anionic and cationic CUR-NP is synthesized using poly-lactic acid and dextran sulfate and then characterized. Female mice are immunosuppressed and inoculated with Candida albicans (Ca) to induce OC. aPDT is performed by applying CUR-NP or free CUR on the dorsum of the tongue, followed by blue light irradiation for five consecutive days. Nystatin is used as positive control. Afterward, Ca are recovered and cultivated. Animals are euthanized for histological, immunohistochemical, and DNA damage evaluation. Encapsulation in NP improves the water solubility of CUR. Nystatin shows the highest reduction of Ca, followed by aPDT mediated by free CUR, which results in immunolabelling of cytokeratins closer to those observed for healthy animals. Anionic CUR-NP does not show antifungal effect, and cationic CUR-NP reduces Ca even in the absence of light. DNA damage is associated with Ca infection. Consecutive aPDT application is a safe treatment for OC.

Future of human Chlamydia vaccine: potential of self-adjuvanting biodegradable nanoparticles as safe vaccine delivery vehicles

INTRODUCTION

There is a persisting global burden and considerable public health challenge by the plethora of ocular, genital and respiratory diseases caused by members of the Gram-negative bacteria of the genus Chlamydia. The major diseases are conjunctivitis and blinding trachoma, non-gonococcal urethritis, cervicitis, pelvic inflammatory disease, ectopic pregnancy, tubal factor infertility, and interstitial pneumonia. The failures in screening and other prevention programs led to the current medical opinion that an efficacious prophylactic vaccine is the best approach to protect humans from chlamydial infections. Unfortunately, there is no human Chlamydia vaccine despite successful veterinary vaccines. A major challenge has been the effective delivery of vaccine antigens to induce safe and effective immune effectors to confer long-term protective immunity. The dawn of the era of biodegradable polymeric nanoparticles and the adjuvanted derivatives may accelerate the realization of the dream of human vaccine in the foreseeable future.

AREAS COVERED

This review focuses on the current status of human chlamydial vaccine research, specifically the potential of biodegradable polymeric nanovaccines to provide efficacious Chlamydia vaccines in the near future.

EXPERT COMMENTARY

The safety of biodegradable polymeric nanoparticles-based experimental vaccines with or without adjuvants and the array of available chlamydial vaccine candidates would suggest that clinical trials in humans may be imminent. Also, the promising results from vaccine testing in animal models could lead to human vaccines against trachoma and reproductive diseases simultaneously.

Nanoparticles for death‑induced gene therapy in cancer (Review)

Due to the high toxicity and side effects of the use of traditional chemotherapy in cancer, scientists are working on the development of alternative therapeutic technologies. An example of this is the use of death‑induced gene therapy. This therapy consists of the killing of tumor cells via transfection with plasmid DNA (pDNA) that contains a gene which produces a protein that results in the apoptosis of cancerous cells. The cell death is caused by the direct activation of apoptosis (apoptosis‑induced gene therapy) or by the protein toxic effects (toxin‑induced gene therapy). The introduction of pDNA into the tumor cells has been a challenge for the development of this therapy. The most recent implementation of gene vectors is the use of polymeric or inorganic nanoparticles, which have biological and physicochemical properties (shape, size, surface charge, water interaction and biodegradation rate) that allow them to carry the pDNA into the tumor cell. Furthermore, nanoparticles may be functionalized with specific molecules for the recognition of molecular markers on the surface of tumor cells. The binding between the nanoparticle and the tumor cell induces specific endocytosis, avoiding toxicity in healthy cells. Currently, there are no clinical protocols approved for the use of nanoparticles in death‑induced gene therapy. There are still various challenges in the design of the perfect transfection vector, however nanoparticles have been demonstrated to be a suitable candidate. This review describes the role of nanoparticles used for pDNA transfection and key aspects for their use in death‑induced gene therapy.

Encapsulation of curcumin in polymeric nanoparticles for antimicrobial Photodynamic Therapy

Curcumin (CUR) has been used as photosensitizer in antimicrobial Photodynamic Therapy (aPDT). However its poor water solubility, instability, and scarce bioavalibility hinder its in vivo application. The aim of this study was to synthesize curcumin in polymeric nanoparticles (NP) and to evaluate their antimicrobial photodynamic effect and cytoxicity. CUR in anionic and cationic NP was synthesized using polylactic acid and dextran sulfate by the nanoprecipitation method. For cationic NP, cetyltrimethylammonium bromide was added. CUR-NP were characterized by physicochemical properties, photodegradation, encapsulation efficiency and release of curcumin from nanoparticles. CUR-NP was compared with free CUR in 10% dimethyl sulfoxide (DMSO) as a photosensitizer for aPDT against planktonic and biofilms (mono-, dual- and triple-species) cultures of Streptococcus mutans, Candida albicans and Methicillin-Resistant Staphylococcus aureus. The cytotoxicity effect of formulations was evaluated on keratinocytes. Data were analysed by parametric (ANOVA) and non-parametric (Kruskal-Wallis) tests (α = 0.05). CUR-NP showed alteration in the physicochemical properties along time, photodegradation similar to free curcumin, encapsulation efficiency up to 67%, and 96% of release after 48h. After aPDT planktonic cultures showed reductions from 0.78 log₁₀ to complete eradication, while biofilms showed no antimicrobial effect or reductions up to 4.44 log₁₀. Anionic CUR-NP showed reduced photoinactivation of biofilms. Cationic CUR-NP showed microbicidal effect even in absence of light. Anionic formulations showed no cytotoxic effect compared with free CUR and cationic CUR-NP and NP. The synthesized formulations improved the water solubility of CUR, showed higher antimicrobial photodynamic effect for planktonic cultures than for biofilms, and the encapsulation of CUR in anionic NP reduced the cytotoxicity of 10% DMSO used for free CUR.

Comb-shaped polymer grafted with REDV peptide, PEG and PEI as targeting gene carrier for selective transfection of human endothelial cells

Several REDV peptide molecules are covalently linked onto an amphiphilic block copolymer to obtain REDV-modified polycationic polymer as a gene carrier with targeting function. The targeting gene complexes show high cell recognition and binding affinity to human endothelial cells.

Building the design, translation and development principles of polymeric nanomedicines using the case of clinically advanced poly(lactide(glycolide))-poly(ethylene glycol) nanotechnology as a model: An industrial viewpoint

The design of the first polymeric nanoparticles could be traced back to the 1970s, and has thereafter received considerable attention, as evidenced by the significant increase of the number of articles and patents in this area. This review article is an attempt to take advantage of the existing literature on the clinically tested and commercialized biodegradable PLA(G)A-PEG nanotechnology as a model to propose quality building and outline translation and development principles for polymeric nano-medicines. We built such an approach from various building blocks including material design, nano-assembly - i.e. physicochemistry of drug/nano-object association in the pharmaceutical process, and release in relevant biological environment - characterization and identification of the quality attributes related to the biopharmaceutical properties. More specifically, as envisaged in a translational approach, the reported data on PLA(G)A-PEG nanotechnology have been structured into packages to evidence the links between the structure, physicochemical properties, and the in vitro and in vivo performances of the nanoparticles. The integration of these bodies of knowledge to build the CMC (Chemistry Manufacturing and Controls) quality management strategy and finally support the translation to proof of concept in human, and anticipation of the industrialization takes into account the specific requirements and biopharmaceutical features attached to the administration route. From this approach, some gaps are identified for the industrial development of such nanotechnology-based products, and the expected improvements are discussed. The viewpoint provided in this article is expected to shed light on design, translation and pharmaceutical development to realize their full potential for future clinical applications.

Non-toxic polyester urethanes based on poly(lactic acid), poly(ethylene glycol) and lysine diisocyanate

Poly(lactic acid)-based polymers are highly suitable for temporary biomedical applications, such as tissue support or drug delivery systems. Copolymers of different molecular weight based on poly(lactic acid) and poly(ethylene glycol) were prepared by polycondensation, catalysed by hydrochloric acid. A chain-extension reaction with l-lysine ethyl ester diisocyanate was employed afterwards to obtain polyester urethanes with enhanced properties. The GPC results showed that the molecular weights of the products reached about 50,000 g·mol−1 and the hydrolytic progress was rapid in the first 2 weeks; the drop in Mn equalled approximately 70%. Additionally, elemental analysis of the buffer medium proved that hydrolytic degradation was more rapid in the first stage. Tensile-strength testing revealed that ductility increased alongside reduced molecular weight of poly(ethylene glycol), also suggesting that polymer branching occurred due to side reactions of isocyanate. Based on the envisaged biomedical applications for these polymers, cytotoxicity tests were carried out and the cytotoxic effect was only moderate in the case of 100% polymer extract prepared according to ISO standard 10993-12. In their research, the authors focused on preparing metal-free, catalysed synthesis of polyester urethanes, which could prove useful to numerous biomedical applications.

Antibacterial Activity of Ciprofloxacin-Encapsulated Cockle Shells Calcium Carbonate (Aragonite) Nanoparticles and Its Biocompatability in Macrophage J774A.1

The use of nanoparticle delivery systems to enhance intracellular penetration of antibiotics and their retention time is becoming popular. The challenge, however, is that the interaction of nanoparticles with biological systems at the cellular level must be established prior to biomedical applications. Ciprofloxacin-cockle shells-derived calcium carbonate (aragonite) nanoparticles (C-CSCCAN) were developed and characterized. Antibacterial activity was determined using a modified disc diffusion protocol on Salmonella Typhimurium (S. Typhimurium). Biocompatibilittes with macrophage were evaluated using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-Bromo-2'-deoxyuridine (BrdU) assays. Transcriptional regulation of interleukin 1 beta (IL-1β) was determined using reverse transcriptase-polymerase chain reaction (RT-PCR). C-CSCCAN were spherical in shape, with particle sizes ranging from 11.93 to 22.12 nm. Encapsulation efficiency (EE) and loading content (LC) were 99.5% and 5.9%, respectively, with negative ζ potential. X-ray diffraction patterns revealed strong crystallizations and purity in the formulations. The mean diameter of inhibition zone was 18.6 ± 0.5 mm, which was better than ciprofloxacin alone (11.7 ± 0.9 mm). Study of biocompatability established the cytocompatability of the delivery system without upregulation of IL-1β. The results indicated that ciprofloxacin-nanoparticles enhanced the antibacterial efficacy of the antibiotic, and could act as a suitable delivery system against intracellular infections.

Non-viral therapeutic approaches to ocular diseases: An overview and future directions

Currently there are no viable treatment options for patients with debilitating inherited retinal degeneration. The vast variability in disease-inducing mutations and resulting phenotypes has hampered the development of therapeutic interventions. Gene therapy is a logical approach, and recent work has focused on ways to optimize vector design and packaging to promote optimized expression and phenotypic rescue after intraocular delivery. In this review, we discuss ongoing ocular clinical trials, which currently use viral gene delivery, but focus primarily on new advancements in optimizing the efficacy of non-viral gene delivery for ocular diseases. Non-viral delivery systems are highly customizable, allowing functionalization to improve cellular and nuclear uptake, bypassing cellular degradative machinery, and improving gene expression in the nucleus. Non-viral vectors often yield transgene expression levels lower than viral counterparts, however their favorable safety/immune profiles and large DNA capacity (critical for the delivery of large ocular disease genes) make their further development a research priority. Recent work on particle coating and vector engineering presents exciting ways to overcome limitations of transient/low gene expression levels, but also highlights the fact that further refinements are needed before use in the clinic.

Preparation and antitumor effect evaluation of composite microparticles co-loaded with siRNA and paclitaxel by a supercritical process

The co-delivery of siRNA and therapeutic agents provides an effective method for cancer chemotherapy by avoiding drug resistance during the treatment. With a combination of ionic gelation and supercritical fluid technology, nanoparticle-embedded composite microparticles (CMPs) co-loaded with siRNA and paclitaxel (siRNA-PTX-CMPs) were successfully prepared. The results show that CMPs embedded with nanoparticles with a diameter of 50-100 nm exhibited a spherical shape and core-shell structure with a mean diameter of 323 nm. The encapsulation efficiency of siRNA in chitosan nanoparticles (CS NPs) was 96.97%. The drug load and encapsulation efficiency of PTX-loaded CMPs (5% dosage) were 1.40% and 27.95%, respectively; both these increased with an increase in dosage. It was found that no change had occurred in the functional groups of the components during the supercritical process, while the physical form of PTX had shifted to an amorphous state. In the cell experiments, the CMPs clustered around the nucleus after being taken up by the Bcap-37 cells. The results of the antitumor effect experiments revealed that the co-loaded siRNA-PTX-CMPs achieved a significantly better synergistic effect than single dosages, which indicated that the co-delivery system developed by the supercritical process could have potential in the application of cancer chemotherapy.

Potential of Nanomaterials as Movers and Packers for Drug Molecules

As the development of nanotechnology has extended to the world of biomolecules, a revolution has occurred in the design and assembly of nanomaterials for drug delivery with a significant potential to impact drug efficacy and patient outcomes. Currently a number of nanomaterials are under investigation for their suitability as sustained, controlled and targeted drug carriers. Leading edge of the rapidly developing nanosciences is the development and assessment of these nanomaterials, with specific physicochemical properties different from their larger/ bulk counterparts, as vehicles for transport of small and large drug molecules. The characteristics such as size, shape, chemical composition, surface structure and charge, aggregation and agglomeration, and solubility, can greatly influence interactions of these nanostructured systems or carriers with biomembranes and cells. The selectivity and reactivity achieved due to the very small size assigns these systems with a wide spectrum of applications. In this review, nanomaterials are considered in terms of the physical attributes or pharmaceutical effects allocated by them to the all-inclusive carrier or vehicle system (s). However we will limit our discussion to lipidic and polymeric nanomaterials, the two most commonly promoted, and safe nanosystems for delivery of both, the chemical or small molecular entities (SME) and the macromolecules including genes and siRNA.Contents of Paper

In vitro performance of lipid-PLGA hybrid nanoparticles as an antigen delivery system: lipid composition matters

Due to the many beneficial properties combined from both poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and liposomes, lipid-PLGA hybrid NPs have been intensively studied as cancer drug delivery systems, bio-imaging agent carriers, as well as antigen delivery vehicles. However, the impact of lipid composition on the performance of lipid-PLGA hybrid NPs as a delivery system has not been well investigated. In this study, the influence of lipid composition on the stability of the hybrid NPs and in vitro antigen release from NPs under different conditions was examined. The uptake of hybrid NPs with various surface charges by dendritic cells (DCs) was carefully studied. The results showed that PLGA NPs enveloped by a lipid shell with more positive surface charges could improve the stability of the hybrid NPs, enable better controlled release of antigens encapsulated in PLGA NPs, as well as enhance uptake of NPs by DC.

Enhanced gene transfer with multilayered polyplexes assembled with layer-by-layer technique

Successful gene therapy asks for multifunctional vectors which can not only protect DNA from degradation but also transfer it into nuclear and subsequently express the loaded gene. Here we reported a novel multilayered delivery system constructed with DNA, protamine (Pro) and polyethylenimine (PEI) via lay-by-layer (LbL) technique, which posed multifunctions. DNA was previously condensed into a compact core with Pro which also contained nuclear localisation signals (NLS) domains for nuclear transfer. Then additional DNA was deposited as the first layer onto the cationic core via the electrostatic attraction which would increase the loading dose of DNA. At last, PEI was absorbed as the outmost layer to achieve the endosomal escape. Therefore a quaternary polyplexes which offered high loading of DNA, nuclear transfer ability and endosomal escape capability was constructed with the LbL technique. The obtained quaternary polyplexes showed positive surface charge, spherical morphology, a relatively narrow particle size distribution and strong DNA protection capability. Compared with commercially available PEI/DNA complexes, the novel multifuctional vector exhibited not only lower cytotoxicity (P<0.05) but also higher transfection efficiency in HepG2 and HeLa cells (P<0.05) in vitro test.

Polymeric vectors for ocular gene delivery

Gene therapy holds promise for the treatment of many inherited and acquired diseases of the eye. Successful ocular gene therapy interventions depend on efficient gene transfer to targeted cells with minimal toxicity. A major challenge is to overcome both intracellular and extracellular barriers associated with ocular gene delivery. Numerous viral and nonviral vectors were explored to improve transfection efficiency. Among nonviral delivery systems, polymeric vectors have gained significant attention in recent years owing to their nontoxic and non-immunogenic nature. Polyplexes or nanoparticles can be prepared by interaction of cationic polymers with DNA, which facilitate cellular uptake, endolysosomal escape and nuclear entry through active mechanisms. Chemical modification of these polymers allows for the generation of flexible delivery vectors with desirable properties. In this article several synthetic and natural polymeric systems utilized for ocular gene delivery are discussed.

DNase-activatable fluorescence probes visualizing the degradation of exogenous DNA in living cells

This work presents a method to visualize the degradation of exogenous DNA in living cells using a novel type of activatable fluorescence imaging probe. Deoxyribonuclease (DNase)-activatable fluorescence probes (DFProbes) are composed of double strands deoxyribonucleic acid (dsDNA) which is labeled with fluorophore (ROX or Cy3) and quencher on the end of one of its strands, and stained with SYBR Green I. In the absence of DNase, DFProbes produce the green fluorescence signal of SYBR Green I. In the presence of DNase, SYBR Green I is removed from the DFProbes and the labeled fluorophore is separated from the quencher owing to the degradation of DFProbes by DNase, resulting in the decrease of the green fluorescence signal and the occurrence of a red fluorescence signal due to fluorescence resonance energy transfer (FRET). DNase in biological samples was detected using DFProbes and the fluorescence imaging in living cells was performed using DFprobe-modified Au nanoparticles. The results show that DFProbes have good responses to DNase, and can clearly visualize the degradation of exogenous DNA in cells in real time. The well-designed probes might be useful in tracing the dynamic changes of exogenous DNA and nanocarriers in vitro and in vivo.

Novel Strategy to Fabricate PLA/Au Nanocomposites as an Efficient Drug Carrier for Human Leukemia Cells in Vitro

Poly (lactic acid) (PLA) polymer has the promising applications in the biomedical field because of its biodegradability and safe elimination. In this study, we have explored the bio-application of new nanocomposites composed with PLA nanofibers and Au nanoparticles as the potential drug carrier for an efficient drug delivery in target cancer cells. The results demonstrated that the anticancer drug daunorubicin could be efficiently self-assembled on the surface of PLA/Au nanocomposites and the synergistic enhancement of PLA/Au nanocomposites conjugated with daunorubicin into drug-sensitive K562 and drug-resistant leukemia K562/AO2 cells could be obviously observed by MTT assay and confocal fluorescence microscopy studies. These observations suggest that the new nanocomposites could readily induce daunorubicin to accumulate and uptake in target leukemia cells and increase the drug's cytotoxicity. Especially, the PLA/Au nanocomposites could significantly facilitate the cellular drug absorbtion of daunorubicin into drug-resistant K562/AO2 cells and efficiently inhibit the cancer cell proliferation. This raised the possibility to utilize the PLA/Au nanocomposites as a new effective additive agent to inhibit the drug resistance and thus as a novel strategy to sensitively track the respective cancer cells.

A novel cationic liposome formulation for efficient gene delivery via a pulmonary route

The clinical success of gene therapy for lung cancer is not only dependent on efficient gene carriers but also on a suitable delivery route. A pulmonary delivery route can directly deliver gene vectors to the lung which is more efficient than a systemic delivery route. For gene carriers, cationic liposomes have recently emerged as leading non-viral vectors in worldwide gene therapy clinical trials. However, cytotoxic effects or apoptosis are often observed which is mostly dependent on the cationic lipid used. Therefore, an efficient and safe cationic lipid, 6-lauroxyhexyl lysinate (LHLN), previously synthesized by our group was first used to prepare cationic liposomes. Physicochemical and biological properties of LHLN-liposomes were investigated. LHLN-liposome/DNA complexes showed positive surface charge, spherical morphology, a relatively narrow particle size distribution and strong DNA binding capability. Compared with Lipofectamine2000, the new cationic liposome formulation using LHLN exhibited not only lower cytotoxicity (P < 0.05) but also similar transfection efficiency in A549 and HepG2 lung cancer cells for in vitro tests. When administered by intratracheal instillation into rat lungs for in vivo evaluation, LHLN-liposome/DNA complexes exhibited higher pulmonary gene transfection efficiency than Lipofectamine2000/DNA complexes (P < 0.05). These results suggested that LHLN-liposomes may have great potential for efficient pulmonary gene delivery.

Biodegradable tri-block copolymer poly(lactic acid)-poly(ethylene glycol)-poly(l-lysine)(PLA-PEG-PLL) as a non-viral vector to enhance gene transfection

Low cytotoxicity and high gene transfection efficiency are critical issues in designing current non-viral gene delivery vectors. The purpose of the present work was to synthesize the novel biodegradable poly (lactic acid)-poly(ethylene glycol)-poly(l-lysine) (PLA-PEG-PLL) copolymer, and explore its applicability and feasibility as a non-viral vector for gene transport. PLA-PEG-PLL was obtained by the ring-opening polymerization of Lys(Z)-NCA onto amine-terminated NH(2)-PEG-PLA, then acidolysis to remove benzyloxycarbonyl. The tri-block copolymer PLA-PEG-PLL combined the characters of cationic polymer PLL, PLA and PEG: the self-assembled nanoparticles (NPs) possessed a PEG loop structure to increase the stability, hydrophobic PLA segments as the core, and the primary ɛ-amine groups of lysine in PLL to electrostatically interact with negatively charged phosphate groups of DNA to deposit with the PLA core. The physicochemical properties (morphology, particle size and surface charge) and the biological properties (protection from nuclease degradation, plasma stability, in vitro cytotoxicity, and in vitro transfection ability in HeLa and HepG2 cells) of the gene-loaded PLA-PEG-PLL nanoparticles (PLA-PEG-PLL NPs) were evaluated, respectively. Agarose gel electrophoresis assay confirmed that the PLA-PEG-PLL NPs could condense DNA thoroughly and protect DNA from nuclease degradation. Initial experiments showed that PLA-PEG-PLL NPs/DNA complexes exhibited almost no toxicity and higher gene expression (up to 21.64% in HepG2 cells and 31.63% in HeLa cells) than PEI/DNA complexes (14.01% and 24.22%). These results revealed that the biodegradable tri-block copolymer PLA-PEG-PLL might be a very attractive candidate as a non-viral vector and might alleviate the drawbacks of the conventional cationic vectors/DNA complexes for gene delivery in vivo.