Folic‐Acid‐Targeted Self‐Assembling Supramolecular Carrier for Gene Delivery

A targeting gene carrier for cancer‐specific delivery was successfully developed through a “multilayer bricks‐mortar” strategy. The gene carrier was composed of adamantane‐functionalized folic acid (FA‐AD), an adamantane‐functionalized poly(ethylene glycol) derivative (PEG‐AD), and β‐cyclodextrin‐grafted low‐molecular‐weight branched polyethylenimine (PEI‐CD). Carriers produced by two different self‐assembly schemes, involving either precomplexation of the PEI‐CD with the FA‐AD and PEG‐AD before pDNA condensation (Method A) or pDNA condensation with the PEI‐CD prior to addition of the FA‐AD and PEG‐AD to engage host–guest complexation (Method B) were investigated for their ability to compact pDNA into nanoparticles. Cell viability studies show that the material produced by the Method A assembly scheme has lower cytotoxicity than branched PEI 25 kDa (PEI‐25KD) and that the transfection efficiency is maintained. These findings suggest that the gene carrier, based on multivalent host–guest interactions, could be an effective, targeted, and low‐toxicity carrier for delivering nucleic acid to target cells.     

Synthesis and Characterization of Glycol Chitosan DNA Nanoparticles for Retinal Gene Delivery

Given the number of monogenic ocular diseases and the number of non‐monogenic degenerative ocular diseases for which gene therapy is considered as a treatment, the development of effective therapeutic delivery strategies for DNA is a critical research goal. In this work, nonviral nanoparticles (NPs) composed of glycol chitosan (GCS) and plasmid DNA (pDNA) were generated, characterized, and evaluated. These particles are stable, do not aggregate in saline, are resistant to DNases, and have a hydrodynamic diameter of approximately 250 nm. Furthermore, the plasmid in these NPs was shown to maintain its proper conformation and can be released and expressed inside the cell. To determine whether these NPs would be suitable for intraocular use, pDNA carrying the ubiquitously expressed CBA‐eGFP expression cassette was compacted and subretinally injected into adult wild‐type albino mice. At day 14 post‐injection (PI), substantial green fluorescent protein (GFP) expression was observed exclusively in the retinal pigment epithelium (RPE) in eyes treated with GCS NPs but not in those treated with uncompacted pDNA or vehicle (saline). No signs of gross retinal toxicity were observed, and at 30 days PI, there was no difference in electroretinogram function between GCS NP‐, pDNA‐, or vehicle‐treated eyes. These results suggest that with further development, GCS NPs could be a useful addition to the available repertoire of genetic therapies for the treatment of RPE‐associated diseases.     

Novel mucoadhesive polymer: Synthesis and mucoadhesion of poly[acrylic acid‐co‐poly(ethylene glycol) monomethylether monomethacrylate‐co‐dimethylaminoethyl methacrylate]

This study was to design a mucoadhesive based on the biological and physicochemical properties of the buccal mucosa to achieve optimal mucoadhesion in the aqueous buccal environment. Since the buccal surface is negatively charged, a series of novel mucoadhesive poly[acrylic acid‐co‐poly(ethylene glycol) monomethylether monomethacrylate‐co‐dimethylaminoethyl methacrylate] [poly (AA‐PEGMM‐DMEMA)] were synthesized by incorporating the cationic monomer DMEMA into poly(AA‐PEGMM) to enhance the interactions between the mucohadhesive polymer and the buccal mucosa. The compositions of poly(AA‐PEGMM‐DMEMA) were varied by changing the content of DMEMA from 0 to 4.8 mol % while keeping the mole ratio of AA to PEGMM at a constant 9 : 1. It was found that the force of mucoadhesion of poly(AA‐PEGMM‐DMEMA) increased initially, as DMEMA content increased, and reached the maximum at 1% of DMEMA. Further increasing the content of DMEMA decreased the mucoadhesion. The polymers with 0.5 to 2.9% DMEMA appeared to have maximum mucoadhesion after prehydration for 5 min. An ATR–FTIR spectroscopy study revealed that intrapolymer interactions and intersurface interactions played opposite roles in the mucoadhesion performance of the polymers. Optimal mucoadhesion can be achieved by balancing these two interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94:2431–2437, 2004     

Gene Therapy in HIV‐Infected Cells to Decrease Viral Impact by Using an Alternative Delivery Method

The ability of dendrimer 2G‐[Si{O(CH₂)₂N(Me)₂⁺(CH₂)₂NMe₃⁺(I^?)₂}]₈ (NN16) to transfect a wide range of cell types, as well as the possible biomedical application in direct or indirect inhibition of HIV replication, was investigated. Cells implicated in HIV infection such as primary peripheral blood mononuclear cells (PBMC) and immortalized suspension cells (lymphocytes), primary macrophages and dendritic cells, and immortalized adherent cells (astrocytes and trophoblasts) were analyzed. Dendrimer toxicity was evaluated by mitochondrial activity, cell membrane rupture, release of lactate dehydrogenase, erythrocyte hemolysis, and the effect on global gene expression profiles using whole‐genome human microarrays. Cellular uptake of genetic material was determined using flow cytometry and confocal microscopy. Transfection efficiency and gene knockdown was investigated using dendrimer‐delivered antisense oligonucleotides and small interfering RNA (siRNA). Very little cytotoxicity was detected in a variety of cells relevant to HIV infection and erythrocytes after NN16 dendrimer treatment. Imaging of cellular uptake showed high transfection efficiency of genetic material in all cells tested. Interestingly, NN16 further enhanced the reduction of HIV protein 24 antigen release by antisense oligonucleotides due to improved transfection efficiency. Finally, the dendrimer complexed with siRNA exhibited therapeutic potential by specifically inhibiting cyclooxygenase‐2 gene expression in HIV‐infected nervous system cells. NN16 dendrimers demonstrated the ability to transfect genetic material into a vast array of cells relevant to HIV pathology, combining high efficacy with low toxicity. These results suggest that NN16 dendrimers have the potential to be used as a versatile non‐viral vector for gene therapy against HIV infection.     

Bioreducible Guanidinylated Polyethylenimine for Efficient Gene Delivery

Cationic polymers are known to afford efficient gene transfection. However, cytotoxicity remains a problem at the molecular weight for optimal DNA delivery. As such, optimized polymeric gene delivery systems are still a sought‐after research goal. A guanidinylated bioreducible branched polyethylenimine (GBPEI‐SS) was synthesized by using a disulfide bond to crosslink the guanidinylated BPEI (GBPEI). GBPEI‐SS showed sufficient plasmid DNA (pDNA) condensation ability. The physicochemical properties of GBPEI‐SS demonstrate that it has the appropriate size (～200 nm) and surface potential (～30 mV) at a nitrogen‐to‐phosphorus ratio of 10. No significant toxicity was observed, possibly due to bioreducibility and to the guanidine group delocalizing the positive charge of the primary amine in BPEI. Compared with the nonguanidinylated analogue, BPEI‐SS, GBPEI‐SS showed enhanced transfection efficiency owing to increased cellular uptake and efficient pDNA release by cleavage of disulfide bonds. This system is very efficient for delivering pDNA into cells, thereby achieving high transfection efficiency and low cytotoxicity.     

Cyclodextrin‐dendrimer functionalized polysulfone membrane for the removal of humic acid in water

Commercial polysulfone (PSf) membranes were crosslinked with a β‐cyclodextrin‐poly (propyleneimine) (β‐CD‐PPI) conjugate which had β‐CD pendant arms using trimesoyl chloride (TMC) by interfacial polymerization. The morphology and physicochemical properties of the nanofiltration membranes were characterized using Fourier transform infrared/attenuated total reflectance (FT‐IR/ATR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and cross‐flow filtration system. Water‐contact angle, water‐intake capacity, and rejection capacities of the membranes were evaluated. The β‐CD‐G4 (generation 4)‐PPI‐PSf and β‐CD‐G3 (generation 3)‐PPI‐PSf membranes both exhibited high humic acid rejection of 72% as compared to the commercial PSf which exhibited 57%. The modified membranes were also more hydrophilic (36° to 41°) than PSf (76°). These results suggest that β‐CD‐PPI nanostructures are promising materials for the synthesis of membranes for the removal of humic acid from water. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4428–4439, 2013     

Nucleoside‐Based Self‐Assembling Drugs for Localized Drug Delivery

We have synthesized a range of gelators based on the nucleoside analogues gemcitabine and lamivudine, characterizing representative gels from the series using rheology and transmission electron microscopy. Growth inhibition studies of gemcitabine derivatives confirmed the feasibility of these compounds as novel treatments, indicating the potential of nucleoside‐based gelators for localized drug delivery.     

Microfluidic-Based Cationic Cholesterol Lipid siRNA Delivery Nanosystem: Highly Efficient In Vitro Gene Silencing and the Intracellular Behavior

Safe and efficient delivery of small interfering RNA (siRNA) is essential to gene therapy towards intervention of genetic diseases. Herein, we developed a novel cationic cholesterol lipid derivative (CEL) in which cholesterol hydrophobic skeleton was connected to L-lysine cationic headgroup via a hexanediol linker as the non-viral siRNA delivery carrier. Well-organized CEL/siRNA nanocomplexes (100–200 nm) were prepared by microfluidic-assisted assembly of CEL and siRNA at various N/P ratios. The CEL and CEL/siRNA nanocomplexes have lower cytotoxicity compared with bPEI25k. Delightfully, we disclosed that, in Hela–Luc and H1299–Luc cell lines, the micro-fluidic-based CEL/siRNA nanocomplexes exhibited high siRNA transfection efficiency under both serum-free condition (74–98%) and low-serum circumstances (80–87%), higher than that of lipofectamine 2000. These nanocomplexes also showed high cellular uptake through the caveolae/lipid-raft mediated endocytosis pathway, which may greatly contribute to transfection efficiency. Moreover, the time-dependent (0–12 h) dynamic intracellular imaging demonstrated the efficient delivery to cytoplasm after lysosomal co-localization. The results indicated that the microfluidic-based CEL/siRNA nanosystems possessed good stability, low cytotoxicity, high siRNA delivery efficiency, rapid cellular uptake and caveolae/lipid raft-dependent internalization. Additionally, this study provides a simple approach for preparing and applying a “helper lipid-free” cationic lipid siRNA delivery system as potential nanotherapeutics towards gene silencing treatment of (tumor) diseases.     

Delivery of CRISPR/Cas9 by Novel Strategies for Gene Therapy

Precise editing of the genome of a living body is a goal pursued by scientists in many fields. In recent years, CRISPR (clustered regularly interspaced short palindromic repeat)/Cas (CRISPR-associated) genome-editing systems have become a revolutionary toolbox for gene editing across various species. However, the low transfection efficiency of the CRISPR/Cas9 system to mammalian cells in vitro and in vivo is a big obstacle hindering wide and deep application. In this review, recently developed delivery strategies for various CRISPR/Cas9 formulations and their applications in treating gene-related diseases are briefly summarized. This review should inspire others to explore more efficient strategies for CRISPR system delivery and gene therapy.     

PAMAM Dendrimers Mediate siRNA Delivery to Target Hsp27 and Produce Potent Antiproliferative Effects on Prostate Cancer Cells

RNA interference (RNAi) holds great promise for the treatment of inherited and acquired diseases, provided that safe and efficient delivery systems are available. Herein we report that structurally flexible triethanolamine (TEA) core PAMAM dendrimers are able to deliver an Hsp27 siRNA effectively into prostate cancer (PC‐3) cells by forming stable nanoparticles with siRNA, protecting the siRNA nanoparticles from enzymatic degradation, and enhancing cellular uptake of siRNA. The Hsp27 siRNA resulted in potent and specific gene silencing of heat‐shock protein 27, an attractive therapeutic target in castrate‐resistant prostate cancer. Silencing of the hsp27 gene led to induction of caspase‐3/7‐dependent apoptosis and inhibition of PC‐3 cell growth in vitro. In addition, the siRNA–dendrimer complexes are non‐cytotoxic under the conditions used for siRNA delivery. Altogether, TEA core PAMAM dendrimer‐mediated siRNA delivery, in combination with RNAi that specifically targets Hsp27, may constitute a promising approach for combating castrate‐resistant prostate cancer, for which there is no efficacious treatment.     

Synthesis and Drug‐Delivery Behavior of Chitosan‐Functionalized Graphene Oxide Hybrid Nanosheets

Chitosan‐functionalized graphene oxides (FGOCs) were successfully synthesized. FGOCs were found to significantly improve the solubility of the GO in aqueous acidic media. The presence of organic groups was confirmed by means of XPS and TGA. Restoration of the sp² carbon network and exfoliation of graphene sheets were confirmed by Raman spectroscopy, UV‐visible spectroscopy and WAXD. The SEM and AFM investigations of the resultant FGOCs showed that most of the graphene sheets were individual and few were layered. Controlled release behavior of Ibuprofen and 5‐fluorouracil was then investigated. We found that FGOCs are a promising new material for biological and medical applications.

     

Synthesis of PMMA‐PTHF‐PMMA and PMMA‐PTHF‐PST linear and star block copolymers

Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly‐THF)‐polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF₆ and bis(4,4′ bromo‐methyl benzoyl) peroxide (BBP) or bis (3,5,3′,5′ dibromomethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly‐THF initiators with M_w varying from 7,500 to 59,000 Da. Poly‐THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C to obtain poly(THF‐b‐MMA) block copolymers containing the peroxide group in the middle. Poly(MMA‐b‐THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA‐b‐PTHF‐b‐PMMA and PMMA‐b‐PTHF‐b‐PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT‐IR, DSC, TGA, ¹H‐NMR, and ¹³C‐NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 219–226, 2004     

用于基因转染的阳离子脂质体研究进展

开发高效、低毒、具有靶向性的基因载体是基因治疗的关键。阳离子脂质体因具有低毒性与免疫原性、生物相容性好、易于制备等优点而受到广泛关注,具有良好的应用前景。近年来,人们通过使用各种辅助性成分研发新型材料,对脂质材料进行表面修饰以及制备工艺调整等方法改进阳离子脂质体的性能。从上述几方面综述了此类基因传递载体的研究进展。     

Nanotechnology-Based Strategies to Overcome Current Barriers in Gene Delivery

Nanomaterials are currently being developed for the specific cell/tissue/organ delivery of genetic material. Nanomaterials are considered as non-viral vectors for gene therapy use. However, there are several requirements for developing a device small enough to become an efficient gene-delivery tool. Considering that the non-viral vectors tested so far show very low efficiency of gene delivery, there is a need to develop nanotechnology-based strategies to overcome current barriers in gene delivery. Selected nanostructures can incorporate several genetic materials, such as plasmid DNA, mRNA, and siRNA. In the field of nanotechnologies, there are still some limitations yet to be resolved for their use as gene delivery systems, such as potential toxicity and low transfection efficiency. Undeniably, novel properties at the nanoscale are essential to overcome these limitations. In this paper, we will explore the latest advances in nanotechnology in the gene delivery field.     

Onium‐functionalised Polymers in the Design of Non‐leaching Antimicrobial Surfaces

Biocides are widely explored in the design of materials and surfaces in order to address a variety of problems, such as biodeterioration, biofouling or infections. Materials with migrating biocides are under scrutiny due to potential health and environmental risks, as well as instability of the antimicrobial activity in time. This paper focuses on the onium‐functionalised polymers in the design of bioactive materials and surfaces, which are capable to kill micro‐organism or efficiently inhibit their growth on contact. The review highlights synthetic and processing routes towards the integration of onium functionalities into solid materials. The influence of materials structure on the antimicrobial activity and possible applications are discussed.

     

The Promising Nanovectors for Gene Delivery in Plant Genome Engineering

Highly efficient gene delivery systems are essential for genetic engineering in plants. Traditional delivery methods have been widely used, such as Agrobacterium-mediated transformation, polyethylene glycol (PEG)-mediated delivery, biolistic particle bombardment, and viral transfection. However, genotype dependence and other drawbacks of these techniques limit the application of genetic engineering, particularly genome editing in many crop plants. There is a great need to develop newer gene delivery vectors or methods. Recently, nanomaterials such as mesoporous silica particles (MSNs), AuNPs, carbon nanotubes (CNTs), and layer double hydroxides (LDHs), have emerged as promising vectors for the delivery of genome engineering tools (DNA, RNA, proteins, and RNPs) to plants in a species-independent manner with high efficiency. Some exciting results have been reported, such as the successful delivery of cargo genes into plants and the generation of genome stable transgenic cotton and maize plants, which have provided some new routines for genome engineering in plants. Thus, in this review, we summarized recent progress in the utilization of nanomaterials for plant genetic transformation and discussed the advantages and limitations of different methods. Furthermore, we emphasized the advantages and potential broad applications of nanomaterials in plant genome editing, which provides guidance for future applications of nanomaterials in plant genetic engineering and crop breeding.     

Poly(ethylene oxide)‐g‐gellan polysaccharide nanocarriers for controlled gastrointestinal delivery of simvastatin

Herein, a novel gellan polysaccharide‐based amphiphilic copolymer was synthesized for the development of simvastatin‐loaded micellar nanoparticles. The nanoparticles were explored for their controlled drug release and improved pharmacodynamic potentials. The copolymer was characterized by Fourier transform infrared spectroscopy (FTIR) and elemental analysis. The onset of copolymer micellization was detected by fluorescence spectroscopy. Simvastatin was loaded into micellar particles by solvent evaporation method and the particles were then characterized by microscopic and light scattering techniques. The physical state of drug was studied by X‐ray diffraction analysis. Pharmacodynamic assessment of the micellar preparations was done on rabbit models. The copolymer formed micellar nanoparticles in water. Critical micellar concentration was 9.12mg/l. The micellar particles (426.8–912.6nm) entrapped a maximum of 18.86% drug. Higher negative zeta potential indicated physical stability of micellar systems. A simple diffusion mechanism was operative in the event of comparatively faster drug release in pH6.8 phosphate buffer solution. No significant drug‐copolymer interaction was traced by FTIR spectroscopy. The amorphization of drug into micellar particles reduced LDL‐cholesterol level by ～45% in hyperlipidemic rabbits and this was about 2.5 times higher than pure drug dispersion. Copolymer micellar nanoparticles of simvastatin could control cholesterol level in hyperlipidemic rabbits and thus had potential in drug delivery applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42399.     

Nanoemulsions as Gene Delivery in Mucopolysaccharidosis Type I—A Mini-Review

Mucopolysaccharidosis type I (MPS I) is a rare monogenic disease in which glycosaminoglycans’ abnormal metabolism leads to the storage of heparan sulfate and dermatan sulfate in various tissues. It causes its damage and impairment. Patients with the severe form of MPS I usually do not live up to the age of ten. Currently, the therapy is based on multidisciplinary care and enzyme replacement therapy or hematopoietic stem cell transplantation. Applying gene therapy might benefit the MPS I patients because it overcomes the typical limitations of standard treatments. Nanoparticles, including nanoemulsions, are used more and more in medicine to deliver a particular drug to the target cells. It allows for creating a specific, efficient therapy method in MPS I and other lysosomal storage disorders. This article briefly presents the basics of nanoemulsions and discusses the current state of knowledge about their usage in mucopolysaccharidosis type I.