Biomimetic liposomal nanozymes improve breast cancer chemotherapy with enhanced penetration and alleviated hypoxia.

BACKGROUND: Doxorubicin (Dox) has been recommended in clinical guidelines for the standard-of-care treatment of breast cancer. However, Dox therapy faces challenges such as hypoxia, acidosis, H2O2-rich conditions and condensed extracellular matrix in TME as well as low targeted ability. METHODS: We developed a nanosystem H-MnO2-Dox-Col NPs based on mesoporous manganese dioxide (H-MnO2) in which Dox was loaded in the core and collagenase (Col) was wrapped in the surface. Further the H-MnO2-Dox-Col NPs were covered by a fusion membrane (MP) of inflammation-targeted RAW264.7 cell membrane and pH-sensitive liposomes to form biomimetic MP@H-MnO2-Dox-Col for in vitro and in vivo study. RESULTS: Our results shows that MP@H-MnO2-Dox-Col can increase the Dox effect with low cardiotoxicity based on multi-functions of effective penetration in tumor tissue, alleviating hypoxia in TME, pH sensitive drug release as well as targeted delivery of Dox. CONCLUSIONS: This multifunctional biomimetic nanodelivery system exhibited antitumor efficacy in vivo and in vitro, thus having potential for the treatment of breast cancer.

Photothermal therapy enhance the anti-mitochondrial metabolism effect of lonidamine to renal cell carcinoma in homologous-targeted nanosystem.

Renal cell carcinoma (RCC) is a common malignant tumor of the urinary system with poor prognosis. Therapeutic drugs for RCC can easily develop resistance or have unignorable toxicity or limited efficiency. Here, the thermosensitive mitochondrial metabolism-interfering anticancer drug lonidamine (LND) was combined with the photothermal material polydopamine (PDA) to treat RCC. To delivery drugs accurately to RCC site, LND and PDA were loaded in stellate mesoporous silica nanoparticles (MSNs) with a large surface area and cloaked with RCC membranes (MLP@M). The results showed that MLP@M exhibited excellent tumor targeting ability. The synergistic effects of LND and PDA in MLP@M were greatly enhanced when triggered by an 808 nm laser. Moreover, the antiproliferative and tumor suppressing abilities were enhanced with good biocompatibility after MLP@M + laser treatment. Additionally, 80% of RCC tumor-bearing mice treated with MLP@M + laser did not relapse. Our study provides a potential therapeutic approach for RCC treatment.

A novel macrophage-mediated biomimetic delivery system with NIR-triggered release for prostate cancer therapy.

BACKGROUND: Macrophages with tumor-tropic migratory properties can serve as a cellular carrier to enhance the efficacy of anti neoplastic agents. However, limited drug loading (DL) and insufficient drug release at the tumor site remain the main obstacles in developing macrophage-based delivery systems. In this study, we constructed a biomimetic delivery system (BDS) by loading doxorubicin (DOX)-loaded reduced graphene oxide (rGO) into a mouse macrophage-like cell line (RAW264.7), hoping that the newly constructed BDS could perfectly combine the tumor-tropic ability of macrophages and the photothermal property of rGO. RESULTS: At the same DOX concentration, the macrophages could absorb more DOX/PEG-BPEI-rGO than free DOX. The tumor-tropic capacity of RAW264.7 cells towards RM-1 mouse prostate cancer cells did not undergo significant change after drug loading in vitro and in vivo. PEG-BPEI-rGO encapsulated in the macrophages could effectively convert the absorbed near-infrared light into heat energy, causing rapid release of DOX. The BDS showed excellent anti-tumor efficacy in vivo. CONCLUSIONS: The BDS that we developed in this study had the following characteristic features: active targeting of tumor cells, stimuli-release triggered by near-infrared laser (NIR), and effective combination of chemotherapy and photothermotherapy. Using the photothermal effect produced by PEG-BPEI-rGO and DOX released from the macrophages upon NIR irradiation, MAs-DOX/PEG-BPEI-rGO exhibited a significant inhibitory effect on tumor growth.

Topical Ophthalmic Liposomes Dual-Modified with Penetratin and Hyaluronic Acid for the Noninvasive Treatment of Neovascular Age-Related Macular Degeneration.

Introduction: Since intrinsic ocular barrier limits the intraocular penetration of therapeutic protein through eye drops, repeated intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents are the standard therapy for neovascular age-related macular degeneration (nAMD), which are highly invasive and may cause particular ocular complications, leading to poor patient compliance. Methods: Using Penetratin (Pen) as the ocular penetration enhancer and hyaluronic acid (HA) as the retina-targeting ligand, a dual-modified ophthalmic liposome (Penetratin hyaluronic acid-liposome/Conbercept, PenHA-Lip/Conb) eye drop was designed to non-invasively penetrate the ocular barrier and deliver anti-VEGF therapeutic agents to the targeted intraocular tissue. Results: PenHA-Lip effectively penetrates the ocular barrier and targets the retinal pigment epithelium via corneal and non-corneal pathways. After a single topical administration of conbercept-loaded PenHA-Lip (PenHA-Lip/Conb), the intraocular concentration of conbercept peaked at 18.74 ± 1.09 ng/mL at 4 h, which is 11.55-fold higher than unmodified conbercept. In a laser-induced choroidal neovascularization (CNV) mouse model, PenHA-Lip/Conb eye drops three times daily for seven days inhibited CNV formation and progression without any significant tissue toxicity and achieved an equivalent effect to a single intravitreal conbercept injection. Conclusion: PenHA-Lip efficiently and safely delivered conbercept to the posterior eye segment and may be a promising noninvasive therapeutic option for nAMD.

Hepatitis B DNA vaccine-polycation nano-complexes enhancing immune response by percutaneous administration with microneedle.

Percutaneous immune method is becoming an attractive alternative for DNA vaccine as a lot of antigen presenting cells are existed in the viable epidermis. However, due to the barrier function of stratum corneum, it would be hard for DNA vaccine to reach the viable epidermis of the skin. In order to deliver the DNA vaccine successfully cross the stratum corneum, pentagram silicon microneedle array was prepared in this study, and fluorescently labeled nanoparticle was taken as the model to observe the situation inside the skin processed by microneedle. Via microneedle nanoparticles could enter the skin through the micro-channel (diameter about 20-30 µm) and its amount is greatly larger than that enter though the hair follicle of intact skin. A new type of gene vector Pluronic P123-modified polyethyleneimine (P123-PEI) was synthesized by high molecular weight polyethylenimine and Pluronic P123 with the molar ratio of 1 : 1 to take the advantage of P123-PEI as low cytotoxicity and high transfection efficiency. Mice were immunized percutaneously with Hepatitis B DNA vaccine/P123-PEI nano-complexes by microneedle. The humoral and cellular immunity generated in percutaneously immunized mice through microneedle array by Hepatitis B DNA vaccine/P123-PEI nano-complex was significantly higher than that of DNA vaccine intramuscular administration.

Transformer based tooth classification from cone-beam computed tomography for dental charting.

Dental charting is a useful tool in physical examination, dental surgery, and forensic identification. However, manual dental charting faces some difficulties, such as inaccuracy and psychiatric burden in forensic identification. As a critical step of dental charting, tooth classification can be completed on dental cone-beam computed tomography (CBCT) automatically to solve the above difficulties. In this paper, we build a deep neuron network which accepts a 3D CBCT image patch that contains the region of interest (ROI) of a tooth as input and then outputs the type of the tooth. Although Transformer-based neural networks outperform CNN-based neural networks in many natural image processing tasks, they are difficult to apply to 3D medical images. Therefore, we combine the advantages of CNN and Transformer structure to improve the existing methods and propose the Grouped Bottleneck Transformer to overcome the drawbacks of the Transformer, namely the requirement of large training dataset and high computational complexity. We conducted an experiment on a clinical data set containing 450 training samples and 104 testing samples. Experiments show that our network can achieve a classification accuracy of 91.3% and an AUC score of 99.7%. To further evaluate the effectiveness of our method, we tested our network on the publicly available medical image classification dataset MedMNIST3D. The result shows that our network outperforms other networks on 5 out of 6 3-dimensional medical image subsets.

PLGA-PEG-PLGA hydrogel for ocular drug delivery of dexamethasone acetate.

AIM: This study aims to investigate the suitability of thermosensitive triblock polymer poly-(DL-lactic acid-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA as a matrix material for ocular delivery of dexamethasone acetate (DXA). METHODS: The copolymer was synthesized and evaluated for its thermosensitive and gelation properties. DXA in situ gel-forming solution based on PLGA-PEG-PLGA copolymer of 20% (w/w) was prepared and evaluated for ocular pharmacokinetics in rabbit according to the microdialysis method, which was compared to the normal eye drop. RESULT: The copolymer with 20% (w/w) had a low critical solution temperature of 32 degrees C, which is close to the surface temperature of the eye. The C(max) of DXA in the anterior chamber for the PLGA-PEG-PLGA solution was 125.2 microg/mL, which is sevenfold higher than that of the eye drop, along with greater area under the concentration-time curves (AUC). CONCLUSION: These results suggest that the PLGA-PEG-PLGA copolymer is potential thermosensitive in situ gel-forming material for ocular drug delivery, and it may improve the bioavailability, efficacy of some eye drugs.

Design and evaluation of a dry coated drug delivery system with floating-pulsatile release.

The objective of this work was to develop and evaluate a floating-pulsatile drug delivery system intended for chronopharmacotherapy. Floating-pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. To overcome limitations of various approaches for imparting buoyancy, we generated the system which consisted of three different parts, a core tablet, containing the active ingredient, an erodible outer shell and a top cover buoyant layer. The dry coated tablet consists in a drug-containing core, coated by a hydrophilic erodible polymer which is responsible for a lag phase in the onset of pulsatile release. The buoyant layer, prepared with Methocel K4M, Carbopol 934P and sodium bicarbonate, provides buoyancy to increase the retention of the oral dosage form in the stomach. The effect of the hydrophilic erodible polymer characteristics on the lag time and drug release was investigated. Developed formulations were evaluated for their buoyancy, dissolution and pharmacokinetic, as well gamma-scintigraphically. The results showed that a certain lag time before the drug released generally due to the erosion of the dry coated layer. Floating time was controlled by the quantity and composition of the buoyant layer. Both pharmacokinetic and gamma-scintigraphic data point out the capability of the system of prolonged residence of the tablets in the stomach and releasing drugs after a programmed lag time.

Bupivacaine-loaded biodegradable poly(lactic-co-glycolic) acid microspheres I. Optimization of the drug incorporation into the polymer matrix and modelling of drug release.

Bupivacaine has been encapsulated by solvent evaporation method based on O/W emulsion, using poly(DL-lactic-co-glycolic) acid (PLGA) 50:50. The particle size can be controlled by changing stirring rate and polymer concentration. The encapsulation efficiency was affected by polymer concentration and burst effect of bupivacaine released from particles was affected by drug/polymer mass ratio. Orthogonal design was used to optimize the formulation according to drug content, encapsulation efficiency and burst effect. The dissolution profile and release model were evaluated with two different bupivacaine microspheres (bupi-MS) groups including low drug loading (6.41%) and high drug loading (28.92%). It was observed that drug release was affected by drug loading especially the amount of drug crystal attached on surface of bupi-MS. The drug release profile of low drug loaded bupi-MS agreed with Higuchi equation and that of high drug loaded bupi-MS agreed with first order equation.

Modification of degradable nonviral delivery vehicle with a novel bifunctional peptide to enhance transfection in vivo.

AIM: To increase in vivo DNA transfection efficiency of a nonviral delivery vehicle, its tumor targeting and nuclear delivery ability was improved. MATERIALS & METHODS: A novel bifunctional peptide tLyP-1-NLS (named K12) was prepared by coupling a tumor-targeting peptide (tLyP-1) with a nuclear localization signal (NLS), and then was used to modify a degradable polyethyleneimine (PEI) derivative called "N-octyl-N-quaternary chitosan (OTMCS)-PEI". The carrier OTMCS-PEI-K12 was characterized in terms of the physicochemical properties, in vitro gene transfection and antitumor effect in vivo. RESULTS: OTMCS-PEI-K12 showed good suitability, stability and transfection capacity in vitro on the premise of noncytotoxicity. OTMCS-PEI-K12/pING4 complexes induced extensive apoptosis of tumor tissues and shrunk the tumor volume of mice noticeably in vivo. CONCLUSION: This study offers a way to enhance in vivo transfection of a nonviral carrier.

Peptide T7-modified polypeptide with disulfide bonds for targeted delivery of plasmid DNA for gene therapy of prostate cancer.

BACKGROUND: Vectors are essential for successful gene delivery. In the present study, a tumor-targeting cationic gene vector, known as the disulfide cross-linked arginine-aspartic acid peptide modified by HAIYPRH (T7) peptide (CRD-PEG-T7), was designed for targeted delivery of plasmid DNA (pDNA) for gene therapy of prostate cancer (PCa). METHODS: The structure of CRD-PEG-T7 was determined and the cellular uptake efficacy, gene transfection efficacy, cytotoxicity, and the targeting effect of the CRD-PEG-T7-plasmid DNA complex were examined. RESULTS: The results demonstrated that the CRD-PEG-T7-plasmid DNA complex was nanosized and had a positively charged surface, good cellular uptake efficacy, minimal cytotoxicity, and a dual-targeting effect as compared with the CRD-PEG-plasmid DNA complex. The peptide T7-modifed new delivery system was able to target the highly expressed transferrin receptor (TfR) on tumor cells with an efficiency four-fold higher than that of the non-modified system. CONCLUSION: The results above indicatd that the CRD-PEG-T7-plasmid DNA complex may prove to be a promising gene delivery system targeting bone-metastatic tumor.

Temozolomide/PLGA microparticles and antitumor activity against glioma C6 cancer cells in vitro.

The purpose of the present study was to develop implantable poly(D,L-lactide-co-glycolide) (PLGA) microparticles for continuous delivery of intact 3,4-dihydro-3-methyl-4-oxoimidazo[5,1-d]-as-tetrazine-8-carboxamide (temozolomide, TM) for about a 1-month period and to evaluate its cytotoxicity against Glioma C6 cancer cells. The emulsifying-solvent evaporation process has been used to form TM-loaded PLGA microparticles. The influences of several preparation parameters, such as initial drug loading, polymer concentration, and stirring rate were investigated. Scanning electron microscopy (SEM) showed that such microparticles had a smooth surface and a spherical geometry, i.e. microspheres. The differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD) results indicated that TM trapped in the microparticles existed in an amorphous or disordered-crystalline status in the polymer matrix. The release profiles of TM from microparticles resulted in biphasic patterns. After an initial burst, a continuous drug release was observed for up to 1 month. Finally, a cytotoxicity test was performed using Glioma C6 cancer cells to investigate the cytotoxicity of TM delivered from PLGA microparticles. It has been found that the cytotoxicity of TM to Glioma C6 cancer cells is enhanced when TM is delivered from PLGA polymeric carrier and, PLGA only did not affect the growth of the cells. Meanwhile, the cytotoxic activity of TM powder disappeared within 12h.

Synergistic effect of reduced polypeptide micelle for co-delivery of doxorubicin and TRAIL against drug-resistance in breast cancer.

Cationic peptides as a non-viral gene vector have become a hotspot of research because of their high transfection efficcacy and safety. Based on our previous study, we synthesized a cationic reduction-responsive vector based on disulfide cross-linked L-arginine, L-histidine and lipoic acid (LHRss) as the co-carrier of both doxorubicin (DOX) and the necrosis factor-related apoptosis-inducing ligand (pTRAIL). The LHRss/DOX/TRAIL construct has reduction-sensitive behavior and an enhanced endosomal escape ability to increase the cytotoxicity of DOX and the transfection efficiency. Further, the LHRss/DOX/TRAIL construct increased the accumulation of DOX and promoted the expression of pTRAIL, thus increasing cellular apoptosis by 83.7% in MCF-7/ADR cells. In addition, the in vivo biodistribution results showed that the LHRss/DOX/TRAIL construct could target tumors well. The in vivo anti-tumor effect study demonstrated that the LHRss/DOX/TRAIL construct inhibited tumor growth markedly, with a tumor inhibitory rate of 94.0%. The co-delivery system showed a significant synergistic anti-tumor effect. The LHRss/DOX/TRAIL construct may prove to be a promising co-delivery vector for the effective treatment of drug resistant breast cancer.

Efficacy of Drug-Eluting Balloons for Patients With In-Stent Restenosis: A Meta-Analysis of 8 Randomized Controlled Trials.

The optimal treatment for in-stent restenosis (ISR) of both bare-metal stent (BMS) and drug-eluting stent (DES) is currently unclear. The aim of this meta-analysis was to assess the role of drug-eluting balloon (DEB) as an optional treatment for ISR. We searched PubMed, MEDLINE, EMBASE, BIOS, and Web of Science from 2005 to July 2014. Eight studies, enrolling 1413 patients were included. Main end points were late lumen loss (LLL), binary in-segment restenosis (BR), major adverse cardiac events (MACEs), target lesion revascularization (TLR), death, myocardial infarction (MI), and stent thrombosis (ST). When compared to plain old balloon angioplasty (POBA), DEB treatment significantly reduced the risk of MACE (risk rato [RR] 0.37, P < .01), death (RR 0.44, P = .04), TLR (RR 0.27, P < .01), BR (RR [95% CI]: 0.23[0.12 to 0.43], P < .01) and associated with better outcomes of LLL ( 0.50 [ 0.65 to 0.35] mm, P < .01). However, the differences were not significant between DEB treatment and DES treatment in all primary and secondary end points. The DEB was a better option to treat ISR when compared to POBA. However, it had similar effects as DES.

Current status of gene therapy for hepatocellular carcinoma, with a focus on gene delivery approaches.

Hepatocellular carcinoma (HCC) is a malignancy with high morbidity and mortality rates, especially in East Asia. Gene therapy is a potential approach for treating HCC. An efficient and safe gene delivery method is a crucial factor for HCC gene therapy. In recent years, gene delivery systems, including viral and non-viral gene vectors, bacteria, and physical methods, have undergone substantial development. Among them, various non-viral vectors have been studied widely and in detail because they are relatively safe and have a high capacity. In this review, we focus on current and emerging HCC delivery techniques and address the challenges involved in the use and improvement of non-viral vectors.

[Expression of proto-oncogenes c-fos and c-jun in osteoblasts activated by excessive fluoride].

OBJECTIVE: To study expression of proto-oncogenes c-fos and its accompanying gene c-jun in osteoblasts activated by action of excessive fluoride in vivo and in vitro. METHODS: Experimental Wistar rats were exposed to sodium fluoride (NaF) added to their drinking water, and NaF was also added in cell culture supernatant for osteoblast-like cells in vitro. Expression of both mRNA and protein of c-fos and c-jun in bone-tissue of rats with chronic fluorosis and cultured osteoblast-like cells were determined by hybridization in situ, Western blot and immunohistochemistry at varied time periods after exposure. RESULTS: Sodium fluoride could stimulate the proliferation of osteoblast in rats with chronic fluorosis and induce expression of both c-fos and c-jun in all envelops of the spine bone, as compared with its control group. Value of optical absorption in mRNA expression of c-fos and c-jun was 139.63 and 126.37, respectively, in rats with NaF plus high-calcium, significantly lower than that in control group with high-calcium only (107.74 and 117.48, respectively) (P < 0.001). Immunohistochemical analysis showed that protein level of c-fos and c-jun was significantly higher in rats with NaF plus high-calcium than that in control rats with high-calcium only, with values of optical absorption of 139.16, 131.15, 149.98 and 149.19 (P < 0.05), respectively, and protein level of c-fos and c-jun was significantly higher in rats with NaF plus low-calcium than that in control rats with low-calcium only, with values of optical absorption of 117.24, 111.46, 132.46 and 129.79 (P < 0.05), respectively. Western blotting showed that level of protein expression of c-fos and c-jun in periosteal osteoblasts was significantly higher in all rat groups with NaF than that in all control groups, with values of optical absorption of 123.32, 116.60, 115.97 and 108.30, respectively. mRNA expression of c-fos and c-jun in osteoblast-like cells treated with NaF for 12 h increased obviously, and remained at high level 48 h after exposure, with values of optical absorption of 114.80, 161.14, 118.20, and 150.41, respectively, as compared with that in control group (P < 0.001 and P < 0.05). CONCLUSIONS: Exposure to excessive fluoride could stimulate activation and proliferation of both osteoblasts in rats and cultured osteoblast-like cells in vitro, and cause enhanced expression of mRNA and protein of both c-fos and c-jun. Over-expression of c-fos could play an important role in development and proliferation of skeletal lesions in rats with chronic fluorosis.

Ocular delivery of cyclosporine A based on glyceryl monooleate/poloxamer 407 liquid crystalline nanoparticles: preparation, characterization, in vitro corneal penetration and ocular irritation.

The purpose of this study was to develop an ophthalmic drug delivery system for cyclosporine A (CsA) based on glyceryl monooleate (GMO)/poloxamer 407 liquid crystalline nanoparticles with reduced ocular irritancy and improved corneal penetration. CsA-loaded liquid crystalline nanoparticles were prepared via fragmentation of a bulk GMO/poloxamer 407 cubic phase gel by high-pressure homogenization and characterized. Corneal permeation and retention was evaluated using modified Franz diffusing cells. Intra-corneal transportation was investigated with fluorescein isothiocyanate (FITC)-labeled liquid crystalline nanoparticles. Ocular irritation was then evaluated using the Draize method. The mean particle size of liquid crystalline nanoparticles was 193.5 nm and the entrapment efficiency was 95.11 ± 0.67%. A bicontinuous cubic phase of cubic P-type was determined using cryo-transmission electron microscopy (cryo-TEM) observation and small angle X-ray diffraction (SAXD) analysis. A 1.52-fold increase in J(s) and a 2.2-fold increase in corneal retention was achieved by liquid crystalline nanoparticles compared with oil solution. In vitro corneal permeation investigated with FITC-labeled liquid crystalline nanoparticles revealed that CsA penetrated across the cornea under the transportation of liquid crystalline nanoparticles. Liquid crystalline nanoparticles exhibited excellent ocular tolerance in the ocular irritation test. This low-irritant vehicle based on liquid crystalline nanoparticles might be a promising system for effective ocular CsA delivery.

Degradable copolymer based on amphiphilic N-octyl-N-quatenary chitosan and low-molecular weight polyethylenimine for gene delivery.

BACKGROUND: Chitosan shows particularly high biocompatibility and fairly low cytotoxicity. However, chitosan is insoluble at physiological pH. Moreover, it lacks charge, so shows poor transfection. In order to develop a new type of gene vector with high transfection efficiency and low cytotoxicity, amphiphilic chitosan was synthesized and linked with low-molecular weight polyethylenimine (PEI). METHODS: We first synthesized amphiphilic chitosan - N-octyl-N-quatenary chitosan (OTMCS), then prepared degradable PEI derivates by cross-linking low-molecular weight PEI with amphiphilic chitosan to produce a new polymeric gene vector (OTMCS-PEI). The new gene vector was characterized by various physicochemical methods. We also determined its cytotoxicity and gene transfecton efficiency in vitro and in vivo. RESULTS: The vector showed controlled degradation. It was very stable and showed excellent buffering capacity. The particle sizes of the OTMCS-PEI/DNA complexes were around 150-200 nm with proper zeta potentials from 10 mV to 30 mV. The polymer could protect plasmid DNA from being digested by DNase I at a concentration of 2.25 U DNase I/µg DNA. Furthermore, they were resistant to dissociation induced by 50% fetal bovine serum and 1100 µg/mL sodium heparin. OTMCS-PEI revealed lower cytotoxicity, even at higher doses. Compared with PEI 25 KDa, the OTMCS-PEI/DNA complexes also showed higher transfection efficiency in vitro and in vivo. CONCLUSION: OTMCS-PEI was a potential candidate as a safe and efficient gene vector for gene therapy.

Degradable polyethylenimine derivate coupled to a bifunctional peptide R13 as a new gene-delivery vector.

BACKGROUND: To solve the efficiency versus cytotoxicity and tumor-targeting problems of polyethylenimine (PEI) used as a nonviral gene delivery vector, a degradable PEI derivate coupled to a bifunctional peptide R13 was developed. METHODS: First, we synthesized a degradable PEI derivate by crosslinking low-molecular-weight PEI with pluronic P123, then used tumor-targeting peptide arginine-glycine-aspartate-cysteine (RGDC), in conjunction with the cell-penetrating peptide Tat (49-57), to yield a bifunctional peptide RGDC-Tat (49-57) named R13, which can improve cell selection and increase cellular uptake, and, lastly, adopted R13 to modify the PEI derivates so as to prepare a new polymeric gene vector (P123-PEI-R13). The new gene vector was characterized in terms of its chemical structure and biophysical parameters. We also investigated the specificity, cytotoxicity, and gene transfection efficiency of this vector in αvß3-positive human cervical carcinoma Hela cells and murine melanoma B16 cells in vitro. RESULTS: The vector showed controlled degradation, strong targeting specificity to αvß3 receptor, and noncytotoxicity in Hela cells and B16 cells at higher doses, in contrast to PEI 25 KDa. The particle size of P123-PEI-R13/DNA complexes was around 100-250 nm, with proper zeta potential. The nanoparticles can protect plasmid DNA from being digested by DNase I at a concentration of 6 U DNase I/µg DNA. The nanoparticles were resistant to dissociation induced by 50% fetal bovine serum and 600 µg/mL sodium heparin. P123-PEI-R13 also revealed higher transfection efficiency in two cell lines as compared with PEI 25 KDa. CONCLUSION: P123-PEI-R13 is a potential candidate as a safe and efficient gene-delivery carrier for gene therapy.

Degradable gene delivery systems based on Pluronics-modified low-molecular-weight polyethylenimine: preparation, characterization, intracellular trafficking, and cellular distribution.

BACKGROUND: Cationic copolymers consisting of polycations linked to nonionic amphiphilic block polymers have been evaluated as nonviral gene delivery systems, and a large number of different polymers and copolymers of linear, branched, and dendrimeric architectures have been tested in terms of their suitability and efficacy for in vitro and in vivo transfection. However, the discovery of new potent materials still largely relies on empiric approaches rather than a rational design. The authors investigated the relationship between the polymers' structures and their biological performance, including DNA compaction, toxicity, transfection efficiency, and the effect of cellular uptake. METHODS: This article reports the synthesis and characterization of a series of cationic copolymers obtained by grafting polyethyleneimine with nonionic amphiphilic surfactant polyether-Pluronic(®) consisting of hydrophilic ethylene oxide and hydrophobic propylene oxide blocks. Transgene expression, cytotoxicity, localization of plasmids, and cellular uptake of these copolymers were evaluated following in vitro transfection of HeLa cell lines with various individual components of the copolymers. RESULTS: Pluronics can exhibit biological activity including effects on enhancing DNA cellular uptake, nuclear translocation, and gene expression. The Pluronics with a higher hydrophilic-lipophilic balance value lead to homogeneous distribution in the cytoplasm; those with a lower hydrophilic-lipophilic balance value prefer to localize in the nucleus. CONCLUSION: This Pluronic-polyethyleneimine system may be worth exploring as components in the cationic copolymers as the DNA or small interfering RNA/microRNA delivery system in the near future.