Chitosan nanoparticles as non-viral gene delivery systems: Determination of loading efficiency

CD56-targeted in vivo genetic engineering of natural killer cells mediates immunotherapy for acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy that starts from bone marrow and spreads to other organs. At the time of diagnosis, both innate and defective natural killer (NK) cells are present in AML patients. The dysfunction of the NK cells is due to the absence of NK cell receptors such as NKG2D on tumor cells that help with tumor immune escape, and also the polycomb protein, EzH2, which plays an important role in the commitment and differentiation of NK cells. The inhibition of EzH2 activates NK cells towards enhanced lytic activity. However, the adoptive transfer of NK cells for cancer treatment is still under scrutiny due to limitations like production cost, vein-to-vein time, and complicated experimental procedures. In order to circumvent these issues, here, in vivo CD56+ NK cell genetic engineering is hypothesized through the CD56-directed delivery of the pSMP-EzH2 shRNA plasmid encapsulated in chitosan nanoparticles (pEzH2@CSNPs@CD56). The pSMP-EzH2 shRNA plasmid was encapsulated in chitosan nanoparticles followed by CD56 antibody conjugation through EDC-NHS chemistry. CD56 antibody-conjugated nanoparticles selectively target CD56+ NK cells and downregulate EzH2 expression in CD56+ NK cells of human PBMCs. The in vitro CD56+ CD3- NK cells were enriched and stably suppressed EzH2 expression to prepare adoptive CD56+ CD3- NK (EzH2-) cells for anti-AML immunotherapy. The in vitro NK (EzH2-) cells and pEzH2@CSNPs@CD56 reduced splenomegaly while immunophenotyping revealed in vivo downregulation of the c-Kit+ leukemia stem cell population along with upregulation of the differentiation markers CD11b and Gr-1 in the peripheral blood and bone marrow of AML1-ETO9a-induced xenograft nude mice. CD56+CD3- and CD56+CD38+ cell populations were significantly increased in the peripheral blood and bone marrow, which indicated NK cell-mediated AML cell killing took place suggesting that use of pEzH2@CSNPs@CD56 is a safe and viable strategy for NK cell-mediated anti-AML immunotherapy.

Polysaccharide-based nanoassemblies: From synthesis methodologies and industrial applications to future prospects

Polysaccharides, due to their remarkable features, have gained significant prominence in the sustainable production of nanoparticles (NPs). High market demand and minimal production cost, compared to the chemically synthesised NPs, demonstrate a drive towards polysaccharide-based nanoparticles (PSNPs) benign to environment. Various approaches are used for the synthesis of PSNPs including cross-linking, polyelectrolyte complexation, and self-assembly. PSNPs have the potential to replace a wide diversity of chemical-based agents within the food, health, medical and pharmacy sectors. Nevertheless, the considerable challenges associated with optimising the characteristics of PSNPs to meet specific targeting applications are of utmost importance. This review provides a detailed compilation of recent accomplishments in the synthesis of PSNPs, the fundamental principles and critical factors that govern their rational fabrication, as well as various characterisation techniques. Noteworthy, the multiple use of PSNPs in different disciplines such as biomedical, cosmetics agrochemicals, energy storage, water detoxification, and food-related realms, is accounted in detail. Insights into the toxicological impacts of the PSNPs and their possible risks to human health are addressed, and efforts made in terms of PSNPs development and optimising strategies that allow for enhanced delivery are highlighted. Finally, limitations, potential drawbacks, market diffusion, economic viability and future possibilities for PSNPs to achieve widespread commercial use are also discussed.

Nano-Based Drug Delivery Systems for Periodontal Tissue Regeneration

Periodontitis is a dysbiotic biofilm-induced and host-mediated inflammatory disease of tooth supporting tissues that leads to progressive destruction of periodontal ligament and alveolar bone, thereby resulting in gingival recession, deep periodontal pockets, tooth mobility and exfoliation, and aesthetically and functionally compromised dentition. Due to the improved biopharmaceutical and pharmacokinetic properties and targeted and controlled drug release, nano-based drug delivery systems have emerged as a promising strategy for the treatment of periodontal defects, allowing for increased efficacy and safety in controlling local inflammation, establishing a regenerative microenvironment, and regaining bone and attachments. This review provides an overview of nano-based drug delivery systems and illustrates their practical applications, future prospects, and limitations in the field of periodontal tissue regeneration.

Modulation of Chitosan-TPP Nanoparticle Properties for Plasmid DNA Vaccines Delivery

Nucleic acid vaccines have become a revolutionary technology to give a fast, safe, cost-effective and efficient response against viral infections, such as SARS-CoV-2 or Human papillomavirus (HPV). However, to ensure their effectiveness, the development of adequate methods to protect, carry, and deliver nucleic acids is fundamental. In this work, nanoparticles (NPs) of chitosan (CS)-tripolyphosphate (TPP)-plasmid DNA (pDNA) were thoroughly modulated and characterized, by measuring the charge and size through dynamic light scattering (DLS) and morphology by scanning electron microscopy (SEM). Stability, cytotoxicity and cellular uptake of NPs were also evaluated. Finally, the effect of polyplexes on the expression of HPV E7 antigen in human fibroblast and RAW cells was investigated through polymerase chain reaction (PCR) and real-time PCR. The results showed NPs with a spherical/oval shape, narrow size distribution <180 nm and positive zeta potentials (>20 mV) and good stability after one month of storage at 4 °C in formulation buffer or when incubated in culture medium and trypsin. In vitro studies of NPs cytotoxicity revealed that the elimination of formulation buffers led to an improvement in the rate of cell viability. The E7 antigen transcription was also increased for NPs obtained with high pDNA concentration (60 μg/mL). The analyzed CS-TPP-pDNA polyplexes can offer a promising vehicle for nucleic acid vaccines, not only in the prevention or treatment of viral infections, but also to fight emergent and future pathogens.

Relationship between phosphorylamine-modification and molecular weight on transfection efficiency of chitosan

The aim of this study is both to design the chitosan (Chi) nanoparticles with different M_w containing the phosphoester bonds and increase their amino function for the transfection. The phosphorylamine-modification of Chi and depolymerized Chi (DChi) was realized using o-phosphorylethanolamine (o-PEA) and characterized, for the first time. The nanoparticles (nMChi and nMDChi) were prepared by ionic gelation and their particle size, polydispersity index (PDI), zeta potential, stability, gene binding capacity and cytotoxicity were examined. The effects of the M_w of Chi on the cytotoxicity, gene binding capacity, and in vitro transfection efficiency of the nanoparticles on Human Embryonic Kidney 293 (HEK293) cells were also examined. Green Fluorescent Protein Circular Plasmid DNA (pEGFN1) loaded nanoparticles (gnMChi and gnMDChi) were used in the transfection. This study showed that the M_w of phosphorylamine-modified Chi significantly affected the characteristics, cytotoxicity, gene binding capacity and transfection efficiency of the nanoparticles.

Anti-EpCAM functionalized graphene oxide vector for tumor targeted siRNA delivery and cancer therapy

Graphene oxide (GO) has emerged as a potential drug delivery vector. For siRNA delivery, GO should be modified to endow it with gene delivery ability and targeting effect. However, the cationic materials used previously usually had greater toxicity. In this study, GO was modified with a non-toxicity cationic material (chitosan) and a tumor specific monoclonal antibody (anti-EpCAM) for the delivery of survivin-siRNA (GCE/siRNA). And the vector (GCE) prepared was proved with excellent biosafety and tumor targeting effect. The GCE exhibited superior performance in loading siRNA, maintained stability in different solutions and showed excellent protection effect for survivin-siRNA in vitro. The gene silencing results in vitro showed that the mRNA level and protein level were down-regulated by 48.24% ± 2.50% and 44.12% ± 3.03%, respectively, which was equal with positive control (P > 0.05). It was also demonstrated that GCE/siRNA had a strong antitumor effect in vitro, which was attributed to the efficient antiproliferation, and migration and invasion inhibition effect of GCE/siRNA. The results in vivo indicated that GCE could accumulate siRNA in tumor tissues. The tumor inhibition rate of GCE/siRNA 54.74% ± 5.51% was significantly higher than control 4.87% ± 8.49%. Moreover, GCE/siRNA showed no toxicity for blood and main organs, suggesting that it is a biosafety carrier for gene delivery. Taken together, this study provides a novel design strategy for gene delivery system and siRNA formulation.

Recent development of gene therapy for pancreatic cancer using non-viral nanovectors

Pancreatic cancer (PC), characterized by its dense desmoplastic stroma and hypovascularity, is one of the most lethal cancers with a poor prognosis in the world. Traditional treatments such as chemotherapy, radiotherapy, and targeted therapy show little benefit in the survival rate in patients with advanced PC due to the poor penetration and resistance of drugs, low radiosensitivity, or severe side effects. Gene therapy can modify the morbific and drug-resistant genes as well as insert the tumor-suppressing genes, which has been shown to have great potential in PC treatment. The development of safe non-viral vectors for the highly efficient delivery of nucleic acids is essential for effective gene therapy, and has been attracting much attention. In this review, we first summarized the PC-promoting genes and gene therapies using plasmid DNA, mRNA, miRNA/siRNA-based RNA interference technology, and genome editing technology. Second, the commonly used non-viral nanovector and theranostic gene delivery nanosystem, especially the tumor microenvironment-sensitive delivery nanosystem and the cell/tumor-penetrating delivery nanosystem, were introduced. Third, a combination of non-viral nanovector-based gene therapy and other therapies, such as immunotherapy, chemotherapy, photothermal therapy (PTT), and photodynamic therapy (PDT), for PDAC treatment was discussed. Finally, a number of clinical trials have demonstrated the proof-of-principle that gene therapy or the combination of gene therapy and chemotherapy using non-viral vectors can inhibit the progression of PC. Although most of the non-viral vector-based gene therapies and their combination therapy are still under preclinical research, the development of genetics, molecular biology, and novel vectors would promote the clinical transformation of gene therapy.

A non-viral nano-delivery system targeting epigenetic methyltransferase EZH2 for precise acute myeloid leukemia therapy

Acute myeloid leukemia (AML), which is common in the elderly population, accounts for poor long-term survival with a high possibility of relapse. The associated lack of currently developed therapeutics is directing the search for new therapeutic targets relating to AML. EZH2 (Enhancer of Zeste Homolog 2) is a histone methyltransferase member of the polycomb-group (PcG) family, and its significant overexpression in AML means it has emerged as a potential epigenetic target. Here, we propose the human serum albumin (HSA) nanoparticle based delivery of small interfering RNA (siRNA), which can target EZH2-expressing genes in AML. EZH2 specific siRNA loaded in a polyethyleneimine (PEI) conjugated HSA nanocarrier can overcome the systemic instability of siRNA and precisely target the AML cell population for increased EZH2 gene silencing. A stable nanosized complex (HSANPs-PEI@EZH2siRNA), achieved via the electrostatic interaction of PEI and EZH2 siRNA, shows increased systemic stability and hemocompatibility, and enhanced EZH2 gene silencing activity in vitro, compared to conventional transfection reagents. HSANPs-PEI@EZH2siRNA-treated AML cells showed downregulated EZH2, which is associated with a reduced level of Bmi-1 protein, and H3K27me3 and H2AK119ub modification. The ubiquitin-mediated proteasomal degradation pathway plays a critical role in the downregulation of associated proteins following HSANPs-PEI@EZH2siRNA exposure to AML cells. c-Myb is the AML-responsive transcription factor that directly binds on the EZH2 promoter and was downregulated in HSANPs-PEI@EZH2siRNA-treated AML cells. The systemic exposure to HSANPs-PEI@EZH2siRNA of AML engrafted immunodeficient nude mice displayed efficient EZH2 gene silencing and a reduced AML cell population in peripheral blood and bone marrow. The present study demonstrates a non-viral siRNA delivery system for epigenetic targeting based superior anti-leukemic therapy.

Targeting Activated Hepatic Stellate Cells Using Collagen-Binding Chitosan Nanoparticles for siRNA Delivery to Fibrotic Livers

Activated hepatic stellate cells (aHSCs) are the main orchestrators of the fibrotic cascade in inflamed livers, with transforming growth factor-beta (TGF-β) being the most potent pro-fibrotic cytokine. Hence, aHSCs serve as interesting therapeutic targets. However, drug delivery to aHSCs is hindered by excessive collagen deposition in the extracellular matrix (ECM) and capillarization of liver sinusoids. Chitosan-nanoparticles (CS-NPs) show intrinsic affinity for collagen, holding potential for drug delivery to fibrotic livers. Here, we employed CS-NPs for anti-TGF-β siRNA delivery, promoting delivery into aHSCs via modification with platelet-derived growth factor receptor-beta binding peptides. In-vitro experiments using aHSCs demonstrated the association of unmodified CS-NPs to the collagen-rich ECM, with reduced intracellular accumulation. Peptide-modified CS-NPs showed a higher propensity to localize intracellularly; however, this was only the case upon ECM-collagen reduction via collagenase treatment. Peptide-modified CS-NPs were more potent than unmodified CS-NPs in reducing TGF-β expression, implying that while collagen binding promotes liver accumulation, it hinders cell-specific siRNA delivery. In-vivo, CS-NPs successfully accumulated in fibrotic livers via collagen binding. Similar to in-vitro findings, when mice were pretreated with collagenase-loaded CS-NPs, the accumulation of peptide-modified NPs increased. Our findings demonstrate the usefulness of NPs modification with targeting ligands and collagenase treatment for aHSCs targeting and highlight the importance of chitosan-collagen binding in drug delivery to fibrotic diseases.

Collagenase loaded chitosan nanoparticles for digestion of the collagenous scar in liver fibrosis: The effect of chitosan intrinsic collagen binding on the success of targeting

A variety of hepatic insults result in the accumulation of collagen-rich new extracellular matrix in the liver, ultimately culminating in liver fibrosis and cirrhosis. For such reasons, approaches looking into digestion of the collagen-rich extracellular matrix present an interesting therapeutic approach for cases of chronic liver disease, where the fibrotic scar is well established. Portal collagenase administration has recently led to the successful reversion of cirrhosis in an experimental rabbit model. Notwithstanding, the question of how such a sensitive therapeutic macromolecule could be administered in a less invasive manner, and in a way that preserves its functionality and avoids digestion of other non-hepatic vital collagen presents itself. Chitosan is a biodegradable polymer that has been reported to interact and bind to collagen. Chitosan nanoparticles (CS NPs) have also been reported to encapsulate therapeutic proteins, maintaining their functional form and protecting them from in-vivo degradation. For such reasons, CS NPs were loaded with collagenase and evaluated in-vitro and in-vivo for their ability to target and digest collagen. CS NPs were able to encapsulate collagenase (≈ 60% encapsulation efficiency) and release its content in active form. To determine whether chitosan's collagen interaction would enable NP collagen binding or whether the modification with collagen binding peptides (CBPs) is necessary, CS NPs were modified with the CBP; CCQDSETRTFY. Since the density of targeting ligand and the length of tether play a significant role in the success of active targeting, the surface of NPs was modified with different densities of the CBP either directly or using a polyethylene glycol (PEG) spacer. PEGylated NPs showed higher levels of CBP tagging; high, intermediate and low density of CBPs corresponded to 585.8 ± 33, 252.9 ± 25.3 and 56.5 ± 8.8 µg/mL for PEGylated NPs and 425.56 ± 12.67, 107.91 ± 10.3 and 49.86 ± 3.2 µg/mL for unPEGylated NPs, respectively. In-vitro collagen binding experiments showed that unmodified CS NPs were able to bind collagen and that modification with CBPs either directly or via PEG did not enhance collagen binding. In-vivo experiments demonstrated that unmodified CS NPs were able to reverse fibrosis with a survival rate of 100% at the end of the study, indicating the ability of CS NPs to deliver functional collagenase to the fibrotic liver and making the use of CBPs unnecessary.

Development and characterization of an improved formulation of cholesteryl oleate-loaded cationic solid-lipid nanoparticles as an efficient non-viral gene delivery system

Nanoparticle-mediated plasmid delivery is considered a useful tool to introduce foreign DNA into the cells for the purpose of DNA vaccination and/or gene therapy. Cationic solid-lipid nanoparticles (cSLNs) are considered one of the most promising non-viral vectors for nucleic acid delivery. Based on the idea that the optimization of the components is required to improve transfection efficiency, the present study aimed to formulate and characterize cholesteryl oleate-containing solid-lipid nanoparticles (CO-SLNs) incorporating protamine (P) to condense DNA to produce P:DNA:CO-SLN complexes as non-viral vectors for gene delivery with reduced cytotoxicity and high cellular uptake efficiency. For this purpose, CO-SLNs were used to prepare DNA complexes with and without protamine as DNA condenser and nuclear transfer enhancer. The main physicochemical characteristics, binding capabilities, cytotoxicity and cellular uptake of these novel CO-SLNs were analyzed. Positively charged spherical P:DNA:CO-SLN complexes with a particle size ranging from 330.1 ± 14.8 nm to 347.0 ± 18.5 nm were obtained. Positive results were obtained in the DNase I protection assay with a protective effect of the genetic material and 100% loading efficiency was achieved at a P:DNA:CO-SLN ratio of 2:1:7. Transfection studies in human embryonic kidney (HEK293T) cells showed the versatility of adding protamine to efficiently transfect cells, widening the potential applications of CO-SLN-based vectors, since the incorporation of protamine induced almost a 200-fold increase in the transfection capacity of CO-SLNs without toxicity. These results indicate that CO-SLNs with protamine are a safe and effective platform for non-viral nucleic acid delivery.

PEGylated immunoliposome-loaded endoglin single-chain antibody enhances anti-tumor capacity of porcine α1,3GT gene

Tumor could not be completely removed due to the absence of immune storm against tumor. The porcine α1,3 galactosyltransferase (α1,3 GT) induce the hyperacute rejection by synthesizing Galα1-3Galβ1-(3)4GlcNAc-R (αGal) on the surface of graft endothelial cells (ECs) during xeno-transplantation. This study aimed to develop anti-endoglin single-chain Fv fragments (ENG-scFv) conjugated PEGylated immunoliposomes (iLPs) to induce immune storm against tumor. Immune fluorescence was performed to detect the binding of ENG-scFv to human ENG, the endosomal/lysosomal escape of ENG-scFv-iLPs/α1,3 GT, and αGal expression in hENG-HEK293 cells. In vitro MTT assay was performed to measure ENG-scFv-iLPs/α1,3 GT cytotoxicity. NOD/SCID mouse born A549 tumor model was used to evaluate the therapeutic potency of ENG-scFv-iLPs/α1,3 GT. ENG-scFv-iLPs enabled efficient targeting delivery of α1,3 GT plasmid to ENG + tumors neovascular endothelial cells (TnECs), promoted endosomal/lysosomal escape due to the pH-sensitive ability, then synthesized carbohydrate epitope αGal on the surface of these cells to achieve the purpose of destroying the tumor. The mechanism of uptake for nanoparticles was energy driven, the clathrin-mediated endocytosis was the main endocytic pathway of the ENG-mAb-iLPs/α1,3 GT and lipid-raft-mediated of the ENG-scFv-iLPs/α1,3 GT, and macropinocytosis was also involved in intracellular entry. The inhibition of tumor angiogenesis and proliferation by ENG-scFv-iLPs/α1,3 GT was closely related to down-regulation of VEGF. Our findings establish an alternative therapeutic paradigm for scFv-conjugated nanoparticles to induce tumor cell apoptosis and inhibit tumor growth early. Such iLPs nanocarrier could efficiently release α1,3 GT to their distinct sites of action, where the endoglin + tumor neovascular endothelial cells (ENG + TnECs) exist, in a site-specific manner. Therefore, we believe that these scFv-targeted core-shell immunocomplexes are an important potential α1,3 GT delivery system for various solid tumor-targeted therapy.

Novel nano-microspheres containing chitosan, hyaluronic acid, and chondroitin sulfate deliver growth and differentiation factor-5 plasmid for osteoarthritis gene therapy

OBJECTIVE

To construct a novel non-viral vector loaded with growth and differentiation factor-5 (GDF-5) plasmid using chitosan, hyaluronic acid, and chondroitin sulfate for osteoarthritis (OA) gene therapy.

METHODS

Nano-microspheres (NMPs) were prepared by mixing chitosan, hyaluronic acid, and chondroitin sulfate. GDF-5 plasmid was encapsulated in the NMPs through electrostatic adsorption. The basic characteristics of the NMPs were observed, and then they were co-cultured with chondrocytes to observe their effects on extracellular matrix (ECM) protein expression. Finally, NMPs loaded with GDF-5 were injected into the articular cavities of rabbits to observe their therapeutic effects on OA in vivo.

RESULTS

NMPs exhibited good physicochemical properties and low cytotoxicity. Their average diameter was (0.61±0.20) μm, and encapsulation efficiency was (38.19±0.36)%. According to Cell Counting Kit-8 (CCK-8) assay, relative cell viability was 75%-99% when the total weight of NMPs was less than 560 μg. Transfection efficiency was (62.0±2.1)% in a liposome group, and (60.0±1.8)% in the NMP group. There was no significant difference between the two groups (P>0.05). Immunohistochemical staining results suggested that NMPs can successfully transfect chondrocytes and stimulate ECM protein expression in vitro. Compared with the control groups, the NMP group significantly promoted the expression of chondrocyte ECM in vivo (P<0.05), as shown by analysis of the biochemical composition of chondrocyte ECM. When NMPs were injected into OA model rabbits, the expression of ECM proteins in chondrocytes was significantly promoted and the progression of OA was slowed down.

CONCLUSIONS

Based on these data, we think that these NMPs with excellent physicochemical and biological properties could be promising non-viral vectors for OA gene therapy.

Biodegradable Polymeric Nanoparticles for Therapeutic Cancer Treatments

Polymeric nanoparticles have tremendous potential to improve the efficacy of therapeutic cancer treatments by facilitating targeted delivery to a desired site. The physical and chemical properties of polymers can be tuned to accomplish delivery across the multiple biological barriers required to reach diverse subsets of cells. The use of biodegradable polymers as nanocarriers is especially attractive, as these materials can be designed to break down in physiological conditions and engineered to exhibit triggered functionality when at a particular location or activated by an external source. We present how biodegradable polymers can be engineered as drug delivery systems to target the tumor microenvironment in multiple ways. These nanomedicines can target cancer cells directly, the blood vessels that supply the nutrients and oxygen that support tumor growth, and immune cells to promote anticancer immunotherapy.

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.

In vitro and in vivo evaluation of macromolecular prodrug GC-FUA based nanoparticle for hepatocellular carcinoma chemotherapy

A novel type of macromolecular prodrug delivery system is reported in this research. The N-galactosylated-chitosan-5-fluorouracil acetic acid conjugate (GC-FUA) based nanoparticle delivery system was evaluated in vitro and in vivo. Biocompatibility of GC-FUA-NPs was screened by BSA adsorption test and hemolysis activity examination in vitro. Cytotoxicity and cellular uptake study in HepG2 and A549 cells demonstrated that compared to free 5-Fu, the GC-FUA-NPs play great function in killing cancer cells for the cell endocytosis mediated by asialoglycoprotein receptor (ASGPR), which overexpresses on the cell surface. Pharmacokinetics study further illustrated that the drug-loaded nanoparticles has a much longer half-time than free 5-Fu in blood circulation in Sprague-Dawley (SD) rats. Tissue distribution was investigated in Kunming mice, and the result showed that the GC-FUA-NPs have a long circulation effect. The obtained data suggested that GC-FUA-NP is a very promising drug delivery system for efficient treatment of hepatocellular carcinoma.

Characterization and cytocompatibility of thermosensitive hydrogel embedded with chitosan nanoparticles for delivery of bone morphogenetic protein-2 plasmid DNA

A novel injectable chitosan thermosensitive hydrogel was designed as a target multi-effect scaffold for endogenous repair of the periodontium. The hydrogel complex was designed by embedding chitosan nanoparticles (CSn) loaded with bone morphogenetic protein-2 plasmid DNA (pDNA-BMP2) into a chitosan (CS)-based hydrogel with α,β-glycerophosphate (α,β-GP), termed CS/CSn(pDNA-BMP2)-GP. Characterization, the in vitro release profile for pDNA-BMP2, and cytocompatibility to human periodontal ligament cells (HPDLCs), were then conducted. The average diameter of the CSn(pDNA-BMP2) was 270.1 nm with a polydispersity index (PDI) of 0.486 and zeta potential of +27.0 mv. A DNase I protection assay showed that CSn could protect the pDNA-BMP2 from nuclease degradation. Encapsulation efficiency and loading capacity of CSn(pDNA-BMP2) were more than 80 and 30 %, respectively. The sol-gel transition time was only 3 min when CSn(pDNA-BMP2) was added into the CS/α,β-GP system. Scanning electron microscopy showed that CSn(pDNA-BMP2) was randomly dispersed in a network with regular holes and a porous structure. Weighting method showed the swelling ratio and degradation was faster in medium of pH 4.0 than pH 6.8. An in vitro pDNA-BMP2 release test showed that the cumulative release rate of pDNA-BMP2 was much slower from CS/CSn-GP than from CSn in identical release media. In release media with different pH, pDNA-BMP2 release was much slower at pH 6.8 than at pH 4.0. Three-dimensional culture with HPDLCs showed good cell proliferation and the Cell-Counting Kit-8 assay indicated improved cell growth with the addition of CSn(pDNA-BMP2) to CS/α,β-GP. In summary, the CS/CSn(pDNA-BMP2)-GP complex system exhibited excellent biological properties and cytocompatibility, indicating great potential as a gene delivery carrier and tissue regeneration scaffold for endogenous repair of the periodontium.

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.

CD147 monoclonal antibody mediated by chitosan nanoparticles loaded with α-hederin enhances antineoplastic activity and cellular uptake in liver cancer cells

An antibody that specifically interacts with an antigen could be applied to an active targeting delivery system. In this study, CD147 antibody was coupled with α-hed chitosan nanoparticles (α-Hed-CS-NPs). α-Hed-CS-CD147-NPs were round and spherical in shape, with an average particle size of 148.23 ± 1.75 nm. The half-maximum inhibiting concentration (IC50) of α-Hed-CS-CD147-NPs in human liver cancer cell lines HepG2 and SMMC-7721 was lower than that of free α-Hed and α-Hed-CS-NPs. α-Hed-induced cell death was mainly triggered by apoptosis. The increase in intracellular accumulation of α-Hed-CS-CD147-NPs was also related to CD147-mediated internalization through the Caveolae-dependent pathway and lysosomal escape. The higher targeting antitumor efficacy of α-Hed-CS-CD147-NPs than that α-Hed-CS-NPs was attributed to its stronger fluorescence intensity in the tumor site in nude mice.

The effect of glycosaminoglycan content on polyethylenimine-based gene delivery within three-dimensional collagen-GAG scaffolds

The design of biomaterials for increasingly complex tissue engineering applications often requires exogenous presentation of biomolecular signals. Integration of gene delivery vectors with a biomaterial scaffold offers the potential to bypass the use of expensive and relatively inefficient growth factor supplementation strategies to augment cell behavior. However, integration of cationic polymer based gene delivery vectors within three-dimensional biomaterials, particularly matrices which can carry significant surface charge, remains poorly explored. We examined the potential of polyethylenimine (PEI) as a gene delivery vector for three-dimensional collagen-glycosaminoglycan (CG) scaffolds under development for tendon repair. While acetylated versions of PEI have demonstrated improved transfection efficiency in 2D culture assays, we investigated translation of this effect to a 3D biomaterial that contains significant electrostatic charge. A reporter gene was used to examine the impact of polymer modification, polymer:DNA ratio, and the degree of sulfation of the biomaterial microenvironment on gene delivery in vitro. We observed highest transgene expression in acetylated and unmodified PEI at distinct polymer:DNA ratios; notably, the enhancement often seen in two-dimensional culture for acetylated PEI did not fully translate to three-dimensional scaffolds. We also found highly sulfated heparin-based CG scaffolds showed enhanced initial luciferase expression but not prolonged activity. While PEI constructs significantly reduced tenocyte metabolic health during the period of transfection, heparin-based CG scaffolds showed the greatest recovery in tenocyte metabolic health over the full 2 week culture. These results suggest that the electrostatic environment of three-dimensional biomaterials may be an important design criterion for cationic polymer-based gene delivery.

Mechanism Study of Gene Delivery and Expression in PK-15 Cells Using Magnetic Iron Oxide Nanoparticles as Gene Carriers

The mechanism of gene delivery and expression is one of the most important concerns raised by the development of gene delivery methods. Limited investigation is performed on how magnetic nanoparticles combine with DNA and deliver gene into mammalian cells. In this context, polyethyleneimine (PEI) coated iron oxide magnetic nanoparticles (MNPs) were used as gene carriers for binding and condensing with plasmid DNA expressing enhanced green fluorescent protein (EGFP). The morphology and structure of MNP–DNA complexes were characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). We evidenced that large amounts of DNA wrapped around the surface of MNPs and that the MNPs were physically entrapped by the DNA arranged both horizontally and vertically. EGFP gene was successfully expressed under mediation of an external magnetic field which is necessary to efficiently target EGFP gene to the cells. Fluorescence from EGFP was separately detected in the cell cytoplasm and cell nucleus.