The biological fate of the polymer nanocarrier material monomethoxy poly(ethylene glycol)-

Monomethoxy poly(ethylene glycol)-

Development of α-tocopherol surface-modified targeted delivery of 5-fluorouracil-loaded poly-D, L-lactic-co-glycolic acid nanoparticles against oral squamous cell carcinoma

Objective: The aim of the study to develop surface modified targeted moiety α-tocopherol (α-t) encapsulated with 5-fluorouracil (5-FU)-poly-D, L-lactic-co-glycolic acid nanoparticles (PLGA NPs) toward the anticancer activity against oral squamous cell carcinoma (OSCC). Materials and Methods: 5-FU was conjugated with the polymer, PLGA by ionic cross-linking and α-tocopherol use as a functionalized surface moiety. Characterization, drug entrapment efficiency, and in-vitro drug release system were optimized at different pH 7.4 and pH 4.5. The in-vitro cell was performed to optimize the anticancer activity through MTT assay and apoptotic staining assay was also performed by flow cytometry to evaluate the cellular apoptotic activity and cellular uptake. Results: The particle size was distributed within an average range of 145–162 nm, the polydispersity index values lie 0.16–0.30, and the surface charge was at the negative side, –17mV to –23mV. The in vitro drug release system showed more sympathetic situation at pH 7.4 as compared to pH 4.5, for targeted NPs, approximately 86% and 69%, respectively. The non-targeted 5-FU-PLGA NPs showed drug release of 83% and 64% at pH 7.4 and 4.5 subsequently. In vitro anticancer activity confirmed the intense inhibition by α-t-FU-PLGA NPs of 79.98% after 96 h treatment of SCC15 cells and confirmed the steady-state inhibition of 83.74% after 160 h incubation in comparison to 5-FU-PLGA NPs. Subsequently, the early apoptosis, 27.98%, and 16.45%, and late apoptosis, 47.29%, and 32.57%, suggested the higher apoptosis rate in targeted NPs against OSCC. Conclusions: The surface modified α-t-FU-PLGA NP was treated over SCC15 cells, and the oral cancer cells have shown the high intensity of cellular uptake, which confirmed that the target moiety has successfully invaded over the surface of cancer cells and shown advanced targeted delivery against OSCC

Co-delivery of siRNA and docetaxel by hyaluronic acid modified redox-sensitive disulfide-crosslinked nanoparticles / 中国药科大学学报

@#The aims of this research were to constitute and evaluate one targeting anticancer co-delivery system for both micro-molecularchemotherapeutic drugs(docetaxel, DTX)and small interfering RNA(siRNA)expressed by COX-2. The nanoparticles composed of poly(D, L-lactide-co-glycolide)(PLGA)bearing disulfide-linkaged reducible polyethyleneimine(PEIss)covered by hyaluronic acid(HA). Meanwhile, HA-PEI-PLGA nanoparticles were prepared as control. Firstly, the solvent evaporation was used to the particles which exhibited a core-shell structure with a uniform size of 150-200 nm. The cumulative drug release in two kinds of PBS media(pH 7. 4 and pH 5. 0)during 72 hours indicated that DTX-loaded nanoparticles had sustained-release effect within 24 hours. The cumulative release of DTX of HRPSP NPs in PBS pH 5. 0 was 10%-25% more than that in PBS pH 7. 4, which demonstrated that favored release of DTX from nanoparticles could be achieved in acidic tumor microenvironment. Then, the highest transfection efficiency was observed after 14-16 h incubation at N/P ratio of 40/1. Following the saturation of CD44 receptor, the mean fluorescence intensity of HRPSP NPs from the cells decreased drastically in the case of saturation with free HA before. However, there existed no significance in the fluorescence of RPSP NPs between the cells with and without saturation with free HA, which indicated the nanoparticles′ targeting potential toward tumor cells. In the Western blot, the relative silencing efficiency of Bcl-2, bax, capase-3 and COX-2 mRNAprotein was calculated. In comparison to the control group, the silence efficiencies of bax and capase-3 were both significantly increased while that of Bcl-2 was evidently reduced, particularly in siCOX-2/HRPSP NPs group(P< 0. 01). The similar results were obtained in the silence efficiency of COX-2 protein in which the COX-2 quantity on mRNA and protein decreased. The results suggest that the nanoparticles could achieve the synergistic effect on the combinatorial delivery of siRNA and lipophilic anti-tumor drugs.

Biocompatibility of electrospun nanofiber-PLGA membrane with rat olfactory ensheathing cells / 第二军医大学学报

Objective To explore the biocompatibility of rat olfactory ensheathing cells (OECs) with electrospun nanofiber-PLGA (poly[D, L-lactide-co-glycolide]) membrane. Methods The OECs of adult rats were seeded on the electrospun nanofiber-PLGA membrane. The morphology and adhesion to the membrane of OECs were observed by phase contrast microscopy. The proliferation ability of OECs was evaluated by CFDA SE immunofluorescent at 1-5 days after seeding. The control group was seeded into poly-L-lysine-treated plate. - Moreover, the. electrospun nanofiber-PLGA membrane was also implanted in rats to observe the biocompatibility. Results The purity of OECs obtained from in vitro culture was greater than 90%. Themicroscopic findings showed that the OECs grew well on the electrospun nanofiber-PLGA membrane, with good adhesion ability and good cell state; the cell also had an orientation growth along the nanofibers. The OECs had a normal proliferation in the electrospun nanofiber-PLGA membrane at 1-5 days after seeding, and the cell number was not significantly different from that of the control group. There was no death in rats after the PLGA film was transplanted, and the PLGA membrane was fused with the surrounding tissues, with some degradation at the fusion sites with the tissues. Conclusion The electrospun nanofiber-PLGA membrane shows a satisfactory biocompatibility, and OECs have good adhesion and proliferation on it, indicating that the membrane might be a potential tissue engineering nerve graft when combined with OECs.

Growth Behavior of Endothelial Cells According to Electrospun poly(D,L-Lactic-Co-Glycolic Acid) Fiber Diameter as a Tissue Engineering Scaffold

Investigating the effect of electrospun fiber diameter on endothelial cell proliferation provides an important guidance for the design of a fabric scaffold. In this study, we prepared biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA) fibrous nonwoven mats with different fiber diameters ranged from 200 nm to 5 µm using the electrospinning technique. To control the fiber diameters of PLGA mats, 4 mixture solvents [hexafluoro-2-propanol, 2,2,2,-trifluoroethanol:dimethylformamide (9:1), 2,2,2,-trifluoroethanol:hexafluoro-2-propanol (9:1), chloroform] were used. Average diameters were 200 nm, 600 nm, 1.5 µm, and 5.0 µm, respectively. Stereoscopic structure and spatial characterization of fibrous PLGA mats were analyzed using atomic force microscopy and a porosimeter. The mechanical properties of PLGA mats were analyzed using a universal testing machine. The spreading behavior and infiltration of endothelial cells on PLGA mats were visualized by field emission scanning electron microscopy and hematoxylin and eosin staining. Cell proliferation on different PLGA fibers with different diameters was quantified using the MTT assay. Cells on 200 nm diameter PLGA mats showed rapid attachment and spreading. However, the cells did not penetrate the PLGA mat. Cells cultured on 600 nm and 1.5 µm diameter fibers could infiltrate the pores and cell proliferation was dramatically increased after 14 days. Secreted prostacyclin from endothelial cells on each mat was measured to examine the ability to inhibit platelet activation. This basic study on cell proliferation and fiber diameter with physical characterization provides a foundation for studies examining nonwoven fibrous PLGA mats as a tissue engineering scaffold.

In vitro cytocompatibility of poly-D, L-lactic acid porous scaffolds / 中华创伤杂志

Objective To investigate the in vitro cytocompatibility of three-dimensional porous scaffolds of poly-D,L-lactic acid (PDLLA) and discuss the feasibility of PDLLA as a scaffold for bone tissue engineering.Methods BMSCs of the third passage were seeded on osteogenetic differentiation medium or culture medium containing 20％ volume fraction degraded liquid (PDLLA degradation liquid of 0,3,6,9,and 12 weeks) according to the random number table.Osteogenetic differentiation medium or culture medium without PDLLA was used as controls.Cell viability,cytotoxicity,and osteogenic differentiation were detected for study on cytocompatibility of PDLLA.Scanning electron microscopy was used to observe the growth of BMSCs on the surface of PDLLA scaffolds.Results PDLLA scaffolds presented no significant cytotoxic on the growth of BMSCs.PDLLA scaffolds had no negative effect on cell viability compared with the controls (t3 =-0.441,P =0.671; t6 =1.596,P =0.154; t9 =-0.492,P =0.636; t12 =-1.135,P=0.283).ALP staining and calcium nodule staining were positive and there were no significant differences in ALP and collagen Ⅰ protein quantitative detection compared with the controls.BMSCs grew well on the inner surface of the PDLLA three-dimensional porous scaffolds.Conclusion Three-dimensional porous scaffolds of PDLLA present good cytocompatibility in vitro and can be used as bone tissue engineering scaffolds for subsequent in vivo research.

Preparation and characterization of a new kind of firm/soft adjusted poly(D,L-lactic acid)-polyurethane / 中国组织工程研究

10.3969/j.issn.2095-4344.2013.25.017

Application of Mg-PLGA-rhbFGF stent on angiogenesis in hindlimb ischemia / 国际生物医学工程杂志

ObjectiveTo prepare recombinant human basic fibroblast growth factor (rhbFGF) loaded magnesium-poly(D,L-lactide-co-glycolide) (Mg-PLGA) stent and to evaluate its angiogenesis effect in rat model of hindlimb ischemia.MethodsThe stent was prepared with spiral magnesium (Mg) and loaded with therapeutic agent rhbFGF and PLGA matrix.In vitro drug release study was carried out and the effect was evaluated using a standard animal model of rat hindlimb ischemia.A mechanical drill was conducted and the stent was implanted.The concentrations of Mg2+ in the muscle adjacent to the stent,rat plasma,urine and stools of the experimental animals were tested to analyze the degradation and metabolism of metal Mg.Immunohistochemical staining was performed to evaluate the angiogenesis effect of the stent.ResultsThe drug loaded in the stent could release continuously for about 4 weeks.The concentrations of Mg2+ in the rat plasma,urine and stools were within normal range.Immunohistochemical and quantitative analysis showed that the effect of Mg-PLGA-rhbFGF stent on angiogenesis of rat limb ischemia was better than that of the control group.ConclusionRhbFGF loaded MgPLGA stent could promote angiogenesis of rat limb ischemia,and it may provide theoretical basis for the critical patients suffered from lower limb ischemic disease.

Preparation of sustained-release microspheres containing exenatide and their in vitro release / 第二军医大学学报

Objective: To prepare exenatide-loaded poly (lactic-co-glycolicacid)(PLGA) microspheres and to evaluate their release behavior in vitro. Methods: Exenatide-loaded PLGA microspheres were prepared by W/O/O method using PLGA as vectors. An HPLC approach was established to determine the content and in vitro cumulative release. The physicochemical characteristics of microspheres, including the mean diameter, morphology, drug entrapment efficiency and loading efficiency, were evaluated. Results: The prepared microspheres were well-shaped, with a mean diameter of (51.2±1.97) μm. The drug loading was (4.50±0.13)% and the encapsulation efficiency was (96.5±2.68)%. The first day burst release was (13.19 ± 1.39)% and the in vitro 28-day-cumulative-release was (88.6 ± 0.73)%. Conclusion: The W/O/O method is stable, controllable, and repeatable for preparing exenatide-loaded microspheres using biodegradable polymers PLGA as the vector; the microspheres yield a one-month continuous release and have a bright future in treatment of diabetes mellitus.

Evaluation on the bone regenerative capacity of hyaluronic acid applied poly (D,L-lactic-co-glycolic acid) membranes in rabbit calvarial defect / 대한치과보철학회지

PURPOSE: The objective of the present study was to histologically evaluate durability and bone regeneration capacity of new synthetic membranes in comparison to clinically available collagen membrane. MATERIAL AND METHODS: To the skulls of 12 rabbits, we created 4 bone defects of 6 mm in diameter on each of them. Each of defects were covered with at least one of 5 membranes: No membrane, Collagen (Ossix(TM)), PLGA, HA-coated-PLGA and HA-PLGA/PLGA. After 4, 8, 12 weeks, we cut the skulls and dyed with H-E. And then, the histologic observation was done. RESULTS: In current study, the control group which did not use the membrane showed bone regeneration at 12 weeks and covered the bone defect partially. New bones were formed through the underneath of endocranium, and the upper defect was filled with connective tissues and fats. Collagen membrane (Ossix(TM)) showed new bones after 4 weeks, and they were formed through the membrane which maintained until 12 weeks. PLGA, HA-coated-PLGA, HA-PLGA/PLGA showed bone regeneration after 4 weeks and after 8 weeks, they mostly filled defects. At 12 weeks, we could find new bones and previous bones almost look alike and also, they united well. Membranes were unnoticeable after 4 weeks and were absorbed. CONCLUSION: Bone formation and maturation of PLGA, HA-coated-PLGA and HA-PLGA/PLGA were faster than the control group. They showed no difference on the application of HA and after 4 weeks, they were absorbed.

Study on microneedle technique in enhancement of transdermal nanoparticle delivery / 第二军医大学学报

Objective: To investigate the microneedle technique in enhancement of transdermal nanoparticle delivery and the distribution of poly (D,L-lactic-co-glycolic acid) (PLGA) nanoparticles in the skin and the transdermal microconduits. Methods: Double fluorescent PLGA nanoparticles were used to show the transdermal transport process. Franz diffusion cell was used for the transdermal study. The nanoparticle suspension was added to the donor chamber. The hairless mouse skin in the microneedle group was treated by microneedle technique and that in the control group was not treated. Penetration of nanoparticles was visualized by confocal laser scanning microscopy (CLSM). Distribution of nanoparticle diameter was quantified by HPLC. Results: The CLSM images revealed that the nanoparticles were delivered into the microconduits created by microneedles and entered the epidermis and the dermis. The quantitative results showed that no nanoparticles reached the receptor compartment 48 h after addition of the nanoparticles in both groups. In microneedle group the nanoparticle amount was 125.99 μg/cm2 in the epidermis and 55.31 μg/cm2 in the dermis, with the total amount in the skin being 181.30 μg/cm2; in the the control group, the nanoparticle amount was 42.15 μg/cm2 in the epidermis and 32.76 μg/cm2 in the dermis, with the total amount in the skin being 74.91 μg/cm2. Microneedle technique significantly increased the amount of nanoparticles entering the skin (P<0.01), and the amount in the epidermis was significantly more than that in the dermis (P<0.01). Conclusion: Our results suggest that microneedles can enhance the intradermal PLGA nanoparticle delivery, and the nanoparticles deposit in the skin to achieve sustainable drug release, which is beneficial for topical drug administration.

Preparation of magnetic poly D, L-lactide-co-glycolide oxymatrine nanoparticles and their preventive effect against liver fibrosis in mice / 第二军医大学学报

Objective:To prepare magnetic poly D, L-lactide-co-glycolide oxymatrine nanoparticle(M-PLGA-OM-NP) and investigate its preventive effects against experimental liver fibrosis. Methods: The M-PLGA-OM-NP was prepared by multiple emulsion process and observed by transmission electron microscope(TEM). Dimethylnitrosamine (DMN)-induced liver fibrosis was established with mice. After intervention with M-PLGA-OM-NP, the expression of α-smooth muscle actin (a-SMA) in the livers of mice was detected by immunohistochemical assay and the score of liver fibrosis was determined by H-E staining and Van Gieson (VG) staining. Results: The prepared M-PLGA-OM-NP was in a regular sphere shape, with a mean diameter of 146.5 nm; the drug loading was 7.61% and the encapsulation ratio was 44.8%. The serum Alt level in the M-PLGA-OM-NP group was decreased compared with that in the model group. Light microscopy revealed that the fibrosis in the M-PLGA-OM-NP group was greatly improved compared with the model group and pure oxymatrine group. The expression of a-SMA, the marker of hepatic stellate cell activation, was obviously decreased in the M-PLGA-OM-NP group compared with that in the other groups.Conclusion: The prepared M-PLGA OM-NP under magnetic field can reinforce the preventive effect of oxymatrine against DMNinduced experimental liver fibrosis in mice. Conclusion: The prepared M-PLGA-OM-NP under magnetic field can reinforce the preventive effect of oxymatrine against DMNinduced experimental liver fibrosis in mice.

Preparation and characterization of magnetic poly D,L-lactide-co-gylcolide phenylarsine oxide nanoparticles / 第二军医大学学报

Objective: To study the preparation technique for magnetic poly D, L-lactide-co-glycolide phenylarsine oxide nanoparticles (M-PLGA-PAO-NPs) and to characterize the resultant product. Methods: M-PLGA-PAO-NPs were prepared by using emulsion-evaporation process. The morphology of the prepared nanoparticles were observed by transmission electron microscope and the magnetism of the particles was determined by vibrating sample magnetometer. Meanwhile, we also evaluated the mean diameter, encapsulation ratio, and drug loading rate of the particles. Results: The nanoparticles had a regular spherical surface, with 80% of them having a diameter of 140-500 nm. We also found that the drug loading rate of the particles was 3.2 % and the mean encapsulation ratio was 34.2%. The drug had satisfactory magnetic property. Conclusion: Our method can obtain M-PLGA-PAO-NP with satisfactory quality, it is simple-to-use and the prepared particles can meet the requirement of pharmaceutics..

Low Frequency Ultrasound Triggering Drug Release from Improved PLGA Microcapsules in Vitro / 中国康复理论与实践

@# Objective To study the effect of low frequency on drug release from improved PLGA microcapsules, and investigate the possibility of utilizing PLGA microcapsules as the carrier of ultrasound targeted drug delivery system to deliver drug into brain. Methods Doxorubicin loaded poly (D,L lactic-co-glycolic acid) (PLGA) microcapsules were prepared via double emulsion solvent evaporate method and coated with either chitosan or gelatin. In vitro drug release profile and the drug release rate under the exposure of low frequency pulsed ultrasound (25 kHz) and continuous wave ultrasound (35.1 kHz) were assayed. Results The coating with chitosan or gelatin can depress the burst of drug release. The drug release rate from uncoated and chitosan-coated microcapsules did not changed with the exposure of ultrasound, and the rate of gelatin-coated microcapsules did increased. The effect of pulsed ultrasound was stronger than that of continuous ultrasound. Conclusion The drug release from gelatin-coated PLGA microcapsules can be controlled and triggered by 25 kHz pulsed ultrasound, which may be a potent carrier of targeting drugs into brain.

Preparation and characterization of magnetic poly D,L-lactide-co-glycolide phenylarsine oxide nanoparticles / 第二军医大学学报

Objective:To study the preparation technique for magnetic poly D,L-lactide-co-glycolide phenylarsine oxide nanoparticles (M-PLGA-PAO-NPs) and to characterize the resultant product. Methods: M-PLGA-PAO-NPs were prepared by using emulsion-evaporation process. The morphology of the prepared nanoparticles were observed by transmission electron microscope and the magnetism of the particles was determined by vibrating sample magnetometer. Meanwhile, we also evaluated the mean diameter, encapsulation ratio, and drug loading rate of the particles. Results: The nanoparticles had a regular spherical surface, with 80% of them having a diameter of 140-500 nm. We also found that the drug loading rate of the particles was 3.2% and the mean encapsulation ratio was 34.2%. The drug had satisfactory magnetic property. Conclusion: Our method can obtain M-PLGA-PAO-NP with satisfactory quality, it is simple-to-use and the prepared particles can meet the requirement of pharmaceutics.

Immunotherapy with Recombinant House Dust Mite Group 2 Allergen Vaccine Inhibits Allergic Airway Inflammation in Mice / 中国寄生虫学与寄生虫病杂志

Objective To investigate the efficacy and mechanism of subcutaneously given recombinant Der p 2 entrapped PLGA nanoparticles(DEPN) on mouse model with allergic airway inflammation.Methods 40 BALB/c mice were randomly divided into 5 groups,group A(normal control) were treated with saline(100 ?l) all the time,groups B,C,D and E were sensitized intraperitoneally with crude dust mite extracts(10 ?g) and then subcutaneously treated respectively with PBS(100 ?l),2 mg empty PLGA(EP),100 ?g rDer p 2,and 2 mg DEPN(loaded with 100 ?g rDer p 2) for 3 times,once per day,followed by intranasal challenge of 50 ?g rDer p 2.One day post challenge,mice were sacrificed and bronchoalveolar lavage fluid(BALF) was collected.Number of the total cells and eosinophils was determined,and airway inflammation and mucus secretion were analyzed by haematoxylin and eosin(H&E) staining and periodic acid-Schiff(PAS) staining.Level of cytokines in the supernatant of splenocyte culture was assayed by ELISA.Level of rDer p 2 specific IgG2a and IgE in the sera was determined by ELISA.Results The lung histology showed development of eosinophil infiltration in the airway of mice in groups B and C.The lung inflammation and mucus secretion in groups D and E were significantly alleviated than that of groups B and C.Number of total cells(63.50?5.12) andeosinophils(15.32?3.04) in BALF decreased in group B.Compared with group B,the number of total cells in groups D(55.3?5.20) ? 104 /ml and E(41.00?4.91) ?104 /ml greatly decreased(P

BIODEGRADABLE POLY (D,L-LACTIDE-CO-GLYCOLIC ACID) MICROSPHERES USED AS ADJUVANT IN DNA IMMUNIZATION OF HEPATITIS B VIRUS S GENE / 微生物学通报

Study the immunological adjuvant function of biodegradable microspheres for DNA immunization. Empty poly (D, L-lactide-co-glycolic acid) microspheres were prepared using the water- inoil-in-water (w-o-w) technique; A plasmid DNA pRc-CMV encoding hepatitis B virus S antigen was constructed; The mixture of the microspheres and the plasmid DNA was prepared by incubation method. The mixture was administered to Balb/c mice by intramuscular injection. Result: The high antibody titer(1:1600) of intramuscular injection of the mixture of microspheres and the plasmid DNA was obtained, similar to that of intramuscular injection of the mixture of AL(OH)3 and hepatitis B virus S antigen; while intramuscular injection the plasmid DNA elicited no serum antibody respones. Conclusion: biodegradable microspheres may be used as an good adjuvant for DNA immunization.

Interaction of two LAC repressor protein segments with polynucleotides.

The interaction of the oligopeptides Ala-Gln-GIn-Leu-Ala-Gly-OH and Gln-Leu- Ala-Gly-OMe corresponding, respectively, to the sequence 53–58 and 55–58 of lac repressor protein with four polynucleotides was studied. The two peptides did not interact with poly dA. poly dT, poly d(A-T).poly d(A-T) or poly d(A-G).poly d(C-T). But they interacted in a characteristic way with poly d(A-C). poly d (G-T), the sequences of which are in abundance in the lac operator region. Both the peptides stabilised the melting of poly d (A-C). poly d (G-T) at a peptide to nucleotide ratio (P/N) of 4; at lower ratios, they destabilised the DNA slightly. The circular dichroism of the alternating polynucleotide with CAC/GTG sequences was perturbed by both the oligopeptides. The hexapeptide at a P/N of 4 caused the transformation of the Bform circular dichroism spectrum to a new state, characterised by strong 220 and 240 nm bands, and a rather weak long wavelength spectrum.