Biodegradation of various grades of polyethylene microplastics by Tenebrio molitor and Tenebrio obscurus larvae: Effects on their physiology.

Polyethylene (PE) is the most productive plastic product and includes three major polymers including high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) variation in the PE depends on the branching of the polymer chain and its crystallinity. Tenebrio obscurus and Tenebrio molitor larvae biodegrade PE. We subsequently tested larval physiology, gut microbiome, oxidative stress, and PE degradation capability and degradation products under high-purity HDPE, LLDPE, and LDPE powders (<300 µm) diets for 21 days at 65 ± 5% humidity and 25 ± 0.5 °C. Our results demonstrated the specific PE consumption rates by T. molitor was 8.04-8.73 mg PE ∙ 100 larvae-1⋅day-1 and by T. obscurus was 7.68-9.31 for LDPE, LLDPE and HDPE, respectively. The larvae digested nearly 40% of the ingested three PE and showed similar survival rates and weight changes but their fat content decreased by 30-50% over 21-day period. All the PE-fed groups exhibited adverse effects, such as increased benzoquinone concentrations, intestinal tissue damage and elevated oxidative stress indicators, compared with bran-fed control. In the current study, the digestive tract or gut microbiome exhibited a high level of adaptability to PE exposure, altering the width of the gut microbial ecological niche and community diversity, revealing notable correlations between Tenebrio species and the physical and chemical properties (PCPs) of PE-MPs, with the gut microbiome and molecular weight change due to biodegradation. An ecotoxicological simulation by T.E.S.T. confirmed that PE degradation products were little ecotoxic to Daphnia magna and Rattus norvegicus providing important novel insights for future investigations into the environmentally-friendly approach of insect-mediated biodegradation of persistent plastics.

Gut Microbiome Associating with Carbon and Nitrogen Metabolism during Biodegradation of Polyethene in Tenebrio larvae with Crop Residues as Co-Diets.

Tenebrio molitor and Tenebrio obscurus (Coleoptera: Tenebrionidae) larvae are two commercial insects that eat plant and crop residues as diets and also biodegrade synthetic plastics polyethylene (PE). We examined biodegradation of low-density PE (LDPE) foam (Mn = 28.9 kDa and Mw = 342.0 kDa) with and without respective co-diets, i.e., wheat brain (WB) or corn flour (CF), corn straw (CS), and rice straw (RS) at 4:1 (w/w), and their gut microbiome and genetic metabolic functional groups at 27.0 ± 0.5 °C after 28 days of incubation. The presence of co-diets enhanced LDPE consumption in both larvae and broad-depolymerized the ingested LDPE. The diet type shaped gut microbial diversity, potential pathways, and metabolic functions. The sequence of effectiveness of co-diets was WB or CF > CS > RS for larval development and LDPE degradation. Co-occurrence networks indicated that the larvae co-fed with LDPE displayed more complex correlations of gut microbiome than the larvae fed with single diets. The primary diet of WB or CF and crop residues CS and RS provided energy and nitrogen source to significantly enhance LDPE biodegradation with synergistic activities of the gut microbiota. For the larvae fed LDPE and LDPE plus co-diets, nitrogen fixation function was stimulated compared to normal diets and associated with LDPE biodegradation.

Comparison of two methods for tumour-targeting peptide modification of liposomes.

Liposomes decorated with tumour-targeting cell-penetrating peptides can enhance specific drug delivery at the tumour site. The TR peptide, c(RGDfK)-AGYLLGHINLHHLAHL(Aib)HHIL, is pH-sensitive and actively targets tumour cells that overexpress integrin receptor αvß3, such as B16F10 melanoma cells. Liposomes can be modified with the TR peptide by two different methods: utilization of the cysteine residue on TR to link DSPE-PEG2000-Mal contained in the liposome formula (LIPTR) or decoration of TR with a C18 stearyl chain (C18-TR) for direct insertion into the liposomal phospholipid bilayer through electrostatic and hydrophobic interactions (LIPC18-TR). We found that both TR and C18-TR effectively reversed the surface charge of the liposomes when the systems encountered the low pH of the tumour microenvironment, but LIPC18-TR exhibited a greater increase in the charge, which led to higher cellular uptake efficiency. Correspondingly, the IC50 values of PTX-LIPTR and PTX-LIPC18-TR in B16F10 cells in vitro were 2.1-fold and 2.5-fold lower than that of the unmodified PTX-loaded liposomes (PTX-LIP), respectively, in an acidic microenvironment (pH 6.3). In B16F10 tumour-bearing mice, intravenous administration of PTX-LIPTR and PTX-LIPC18-TR (8 mg/kg PTX every other day for a total of 4 injections) caused tumour reduction ratios of 39.4% and 56.1%, respectively, compared to 20.8% after PTX-LIP administration. Thus, we demonstrated that TR peptide modification could improve the antitumour efficiency of liposomal delivery systems, with C18-TR presenting significantly better results. After investigating different modification methods, our data show that selecting an adequate method is vital even when the same molecule is used for decoration.

[Research Development in Transfersome-Based Drug Delivery System].

The transformersome is a new kind of lipoid drug delivery carrier. It has a number of excellent properties, including deformability, pressure permeability, and amphiphilicity. It has been widely used in the field of percutaneous and oral administration of medication. However, due to factors concerning its formulation, the stability and effectiveness of intravenous injection and other systemic routes of administration of transfersomes should be carefully examined. As an alternative, the formulation can be enhanced or improved in order to better exploit the strengths and avoid the weaknesses. Because of its deformability, transfersome may have distinctive potential strengths in the penetration of physiological barriers, for example, the blood-brain barrier, and in the research and development of transdermal immunization vaccines. This review has summarized five aspects of transfersomes, including the main properties, the formulation and process influencing factors, evaluation methods, main administration routes, and problems. Herein, we have given some examples and analysis, summarized the research achievements and assessd prospects for future development.

[Preparation and Characterization of Clopidogrel Bisulfate Liposomes].

OBJECTIVE: To prepare encapsulated clopidogrel bisulfate (CLP) liposomes so as to deal with the poor water solubility of CLP, and to provide the experimental basis for the development of CLP formulations for intravascular injection. METHODS: CLP-loaded liposomes were prepared using thin film hydration/sonication method and pH gradient active drug loading technology. Then, the morphology, particle size, encapsulation efficiency, drug loading capacity, Zeta potentials and in vitro release behavior were characterized. Bilateral renal arteries of Sprague-Dawley (SD) rats were clamped with micro-artery clamps to establish the model of renal ischemia-reperfusion injury (IRI) in male SD rats. The study aimed to preliminarily investigate the therapeutic effect of CLP-loaded liposome pretreatment on renal IRI in rats. RESULTS: It was found that the optimal formulation and preparation technology of CLP liposomes were as follows: the CLP-to-phospholipid weight ratio of 1∶10, phospholipid-to-cholesterol ratio of 6∶1, octadecylamine-to-CLP ratio of 1.2∶1, PEG 400-to-CLP ratio of 1∶1, and incubation at 50 ℃ for 40 min. Then, following ultrasonication of 100 W efficiency at 5-second intervals for 20 times, CLP loading was conducted using 5 mL of 0.1 mol/L citric acid buffer at pH 3.0. Liposome samples were prepared with the film dispersion method, and the pH value was adjusted to 7.5 through pH gradient active drug loading technology. The CLP-loaded liposomes obtained in this way had a rounded shape, good dispersity, an average particle size of (134.13±2.60) nm, polydispersity index (PDI) of 0.25±0.02, and a Zeta potential of (2.12±0.23) mV. The encapsulation efficiency was found to be (98.66±0.14)%, and the drug loading capacity was (7.47±0.01)%. The in vitro release results showed that 66.24% of CLP was released cumulatively within 72 h. Preliminary efficacy experiments showed that animals pretreated with CLP-loaded liposomes had lower serum levels of blood urea nitrogen and creatinine compared to the levels of IRI model rats without any pretreatment. CONCLUSION: CLP-loaded liposomes were successfully prepared, which might provide the experimental foundation for the future development of CLP formulations for injection.

Inflammation-Targeted Delivery of Celastrol via Neutrophil Membrane-Coated Nanoparticles in the Management of Acute Pancreatitis.

Celastrol (CLT)-loaded PEG-PLGA nanoparticles (NPs/CLT) coated with neutrophil membranes (NNPs/CLT) were explored for the management of acute pancreatitis (AP). PEG-PLGA nanoparticles sized around 150 nm were proven to selectively accumulate in the pancreas in rats with AP. NNPs were found to overcome the blood-pancreas barrier and specifically distributed to the pancreatic tissues. Moreover, NNPs showed more selective accumulation in the pancreas than nanoparticles without any membrane coating in AP rats. Compared to CLT solution and the NPs/CLT group, NNPs/CLT significantly downregulated the levels of serum amylase and pancreatic myeloperoxidase in AP rats. Also, using NNPs as the delivery vehicle significantly reduced the systemic toxicity of CLT in AP rats. Together, these results suggest that NNPs/CLT represent a highly promising delivery vehicle for the targeted therapy of AP.

Design and evaluation of glomerulus mesangium-targeted PEG-PLGA nanoparticles loaded with dexamethasone acetate.

Mesangial proliferative glomerulonephritis (MsPGN), one of the most common glomerulonephritis pathological types, often leads to end-stage renal disease over a prolonged period. But the current treatment of MsPGN is non-specific and causes serious side effects, thus novel therapeutics and targeting strategies are urgently demanded. By combining the advantages of PEG-PLGA nanoparticles and the size selection mechanism of renal glomerulus, we designed and developed a novel PEG-PLGA nanoparticle delivery system capable of delivering dexamethasone acetate (A-DEX) into glomerular mesangium. We determined that 90 nm was the optimum size to encapsulate A-DEX for glomerular mesangium targeting based on the size-selection mechanism of glomerulus. After intravenous administration in rats, 90 nm DiD-loaded NPs were found to accumulate to a greater extent in the kidney and kidney cortex compared with the free DiD solution. The 90 nm A-DEX NPs are also more stable at room temperature and showed a sustained release pattern. In rat glomerular mesangial cells (HBZY-1) in vitro, we found that the uptake of 90 nm A-DEX NPs was both temperature-dependent and energe-dependent, and they were mostly engulfed via clathrin-dependent endocytosis pathways. In summary, we have successfully developed a glomerular mesangium-targeted PEG-PLGA NPs, which is potential for the treatment of MsPGN.

A novel gemcitabine derivative-loaded liposome with great pancreas-targeting ability.

Gemcitabine (Gem) is a standard first-line treatment for pancreatic cancer (PC). However, its chemotherapeutic efficacy is hampered by various limitations such as short half-life, metabolic inactivation, and lack of tumor localizing. We previously synthesized a lipophilic Gem derivative (Gem formyl hexadecyl ester, GemC16) that exhibited improved antitumor activity in vitro. In this study, a target ligand N,N-dimethyl-1,3-propanediamine was conjugated to 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[hydroxyl succinimidyl (polyethylene glycol-2000)] (DSPE-PEG-NHS) to form DSPE-PEG-2N. Then, pancreas-targeting liposomes (2N-LPs) were prepared using the film dispersion-ultrasonic method. GemC16-loaded 2N-LPs displayed near-spherical shapes with an average size distribution of 157.2 nm (polydispersity index (PDI) = 0.201). The encapsulation efficiency of GemC16 was up to 97.3% with a loading capacity of 8.9%. In human PC cell line (BxPC-3) and rat pancreatic acinar cell line (AR42J), cellular uptake of 2N-LPs was significantly enhanced compared with that of unmodified PEG-LPs. 2N-LPs exhibited more potent in vitro cytotoxicity against BxPC-3 and AR42J cell lines than PEG-LPs. After systemic administration in mice, 2N-LPs remarkably increased drug distribution in the pancreas. In an orthotopic tumor mouse model of PC, GemC16-bearing liposomes were more effective in preventing tumor growth than free GemC16. Among these treatments, 2N-LPs showed the best curative effect. Together, 2N-LPs represent a promising nanocarrier to achieve pancreas-targeting drug delivery, and this work would provide new ideas for the chemotherapy of PC.

Soluplus micelles for improving the oral bioavailability of scopoletin and their hypouricemic effect in vivo.

Scopoletin is an active coumarin possessing a variety of pharmacological activities, including anti-hyperuricemic effect, but with poor solubility. To improve its oral bioavailability, we attempted to encapsulate scopoletin into Soluplus micelles (Soluplus-based scopoletin micelles, Sco-Ms) and evaluated the hypouricemic action of Sco-Ms. Sco-Ms were prepared using a thin-film hydration method. Sco-Ms displayed near spherical shapes with an average size of 59.4±2.4 nm (PDI=0.08±0.02). The encapsulation efficiency of scopoletin was 87.3%±1.5% with a loading capacity of 5.5%±0.1%. Sco-Ms were further characterized using transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared techniques and scanning electron microscopy. After oral administration in rats, Sco-Ms exhibited significantly improved absorption in each intestinal segment compared to free scopoletin, with the duodenum and jejunum being the main absorption regions. In rats administered Sco-Ms (at an equivalent dose of free scopoletin of 100 mg/kg, po), the AUC0-∞ and Cmax of Sco-Ms were 4.38- and 8.43-fold, respectively, as large as those obtained following administration of free scopoletin. After oral administration in rats, Sco-Ms did not alter the tissue distributions of scopoletin, but significantly increased the scopoletin levels in the liver. In potassium oxonate-induced hyperuricemic mice, oral administration of Sco-Ms (at an equivalent dose of free scopoletin of 300 mg/kg) reduced the serum uric acid concentration to the normal level. The results suggest that Soluplus-based micelle system greatly improves the bioavailability of poorly water-soluble drugs, such as scopoletin, and represents a promising strategy for their oral delivery.

Dissolution and bioavailability enhancement of alpha-asarone by solid dispersions via oral administration.

Alpha (α)-asarone (1-propenyl-2,4,5-methoxybenzol) (ARE) has been extensively used to treat chronic obstructive pulmonary diseases (COPD), bronchial asthma, pneumonia, and epilepsy. Due to its poor solubility and bioavailability, ARE was clinically administered via intravenous injection. However, severe allergies were often reported due to the presence of solublizers in the injection formulation. In our study, we sought to explore the biopharmaceutical classification of ARE, elucidate the mechanisms behind ARE absorption, and to develop a viable formulation to improve the oral bioavailability of ARE. ARE was not a P-glycoprotein substrate, which was absorbed in the passive mode without site specificity in the gastrointestinal tract. Solid dispersions prepared using hydrophilic matrix materials such as Pluronic F68, and polyethylene glycol (PEG) of varying molecular weights (PEG4K, PEG10K, and PEG20K) were proven to significantly improve the dissolution of ARE in vitro and the oral bioavailability of ARE in rats, which represent a promising strategy for the oral administration of ARE and other BCS II compounds.

The implantable and biodegradable PHBHHx 3D scaffolds loaded with protein-phospholipid complex for sustained delivery of proteins.

PURPOSE: PHBHHx (poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)) is an excellent biomaterial for tissue repair. Here, we aim to develop a PHBHHx-based three-dimensional (3D) scaffold system for sustained delivery of proteins (insulin serves as a model protein). METHODS: The insulin-phospholipid complex (INS-PLC) was prepared to enhance the insulin lipophilicity. INS-PLC loaded PHBHHx 3D scaffolds (INS-PLC-SCAs) containing PEG-2000 were fabricated by lyophilization. In vitro release was performed in the medium with or without lipase. The bioactivity of INS-PLC-SCAs was measured in diabetic rats. RESULTS: In vitro release shows that the release rate of INS-PLC-SCAs was very slow (~6% of total insulin was released within 120 days), and PEG-2000 or lipase had no effect on its release pattern. The bioactivity test shows that the hypoglycaemic effect of insulin was maintained after formulated into scaffolds. After subcutaneous (s.c.) implantation, its therapeutic effect lasted for over 130 h, and its bioavailability was enhanced by 4-fold. CONCLUSIONS: PHBHHx based 3D scaffold has a great potential for sustained delivery of proteins, especially growth factors. When growth factors are incorporated, it can serve as a bifunctional system that provides a porous skeleton for cells attachment and proliferation, as well as a matrix for long term release of the loaded growth factors.

[The complexes of adenovirus and anionic liposomes: preparation and in vitro characterization].

This study is to report the preparation of complexes of Ad5 and anionic liposomes (AL-Ad5), the amplification of adenoviruses with enhanced green fluorescent protein (eGFP) reporter gene performed by HEK 293 cells, the adenoviral vectors purified by cesium chloride gradient centrifugation, and the titer of adenovirus determined by cytopathic effect (CPE) method, hexon capsid immunoassay and quantitative-PCR (Q-PCR), separately. The prescription and experiment conditions were optimized by central composite design (CCD). The complexes of Ad5 and AL-Ad5 were formulated by the calcium-induced phase change method. The morpholopy, particle size and zeta potential were detected by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. Additionally, the bicolourable fluoresce-labeled complexes (F(labeled)-AL-Ad5) were prepared and their intracellular location in MDCK cells was detected by confocal laser scanning microscopy (CLSM). The results indicate that the complexes of AL-Ad5 exhibited a uniform distribution with a particle size of 211 +/- 10 nm and a zeta potential of -41.2 +/- 2.2 mV. The result of CLSM demonstrates that the intracellular location of red fluoresce-labeled adenovirus was consistent with that of green fluoresce-labeled liposomes suggesting that the naked adenovirus was well encapsulated by the anionic liposomes in complexes of AL-Ad5.

Impacts of physical-chemical property of polyethylene on depolymerization and biodegradation in yellow and dark mealworms with high purity microplastics.

Yellow and dark mealworms (Tenebrio molitor and Tenebrio obscurus) biodegrade commercial polyethylene (PE) materials at a high rate. We examined the impact of physical and chemical properties on biodegradation using high purity microplastics (MPs). These included high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), all with different weight average molecular weights (Mw) and different crystallinity degrees in T. molitor and T. obscurus larvae. The biodegradation extent in the two mealworms was similar but strongly depended on the polymer type in sequence, since LDPE > LLDPE> HDPE (with respective Mw of 222.5, 110.5 and 182 kDa). When LDPE MPs with Mw of 0.84, 6.4 and 106.8 kDa and HDPE with Mw of 52, 105 and 132.7 kDa were tested, the PE MPs with lower Mw showed a greater extent of depolymerization. The results of dominance analysis indicated that less branching structure and higher crystallinity degree negatively impacted depolymerization and biodegradation. Py-GC/MS analysis confirmed the breaking of the macromolecule backbone as well as the formation of oxidized functional groups after all the tested PE materials passed through the mealworm intestine. The results demonstrated that molecular weight, PE type, branching, and crystallinity degree significantly affect the biodegradation capability of PE by the mealworms, and possibly by other biological systems as well.

pH-sensitive and mucoadhesive microspheres for duodenum-specific drug delivery system.

Particulate systems that could deliver drug specifically to duodenum have not yet been reported. The aim of this study was to develop a novel duodenum-specific drug delivery system based on thiolated chitosan and hydroxypropyl methylcellulose acetate maleate (HPMCAM) for the duodenal ulcer application. Berberine hydrochloride was used as model drug. Thiolated chitosan was synthesized and further used for the preparation of mucoadhesive microspheres. HPMCAM, which is insoluble below pH 3.0 was synthesized and used for the coating of thiolated chitosan microspheres (TCM). The resulting thiolated chitosan immobilized on chitosan was 268.21 ± 18 µmol/g. In vitro mucoadhesion study showed that the mucoadhesion property of TCM was better than that of chitosan microspheres. Morphological observation showed that the HPMCAM coating would maintain its integrity in simulated gastric fluid (SGF) for 2 h and dissolved quickly in simulated pathological duodenal fluid (SPDF; pH 3.3). In vitro drug release studies showed that only 4.75% of the drug was released in SGF for 2 h, while nearly 90% of the drug was released within 6 h after transferring into SPDF.

Confirmation of biodegradation of low-density polyethylene in dark- versus yellow- mealworms (larvae of Tenebrio obscurus versus Tenebrio molitor) via. gut microbe-independent depolymerization.

Tenebrio obscurus (Coleoptera: Tenebrionidae) larvae are capable of biodegrading polystyrene (PS) but their capacity for polyethylene (PE) degradation and pattern of depolymerization remains unknown. This study fed the larvae of T. obscurus and Tenebrio molitor, which have PE degrading capacity, two commercial low-density PE (LDPE) foams i.e., PE-1 and PE-2, with respective number-average molecular weights (Mn) of 28.9 and 27.3 kDa and weight-average molecular weights (Mw) of 342.0 and 264.1 kDa, over a 36-day period at ambient temperature. The Mw of residual PE in frass (excrement) of T. obscurus, fed with PE-1 and PE-2, decreased by 45.4 ± 0.4% and 34.8 ± 0.3%, respectively, while the respective decrease in frass of T. molitor was 43.3 ± 0.5% and 31.7 ± 0.5%. Data analysis showed that low molecular weight PE (<5.0 kDa) was rapidly digested while longer chain portions (>10.0 kDa) were broken down or cleaved, indicating a broad depolymerization pattern. Mass balance analysis indicated nearly 40% of ingested LDPE was digested to CO2. Antibiotic suppression of gut microbes in T. molitor and T. obscurus larvae with gentamicin obviously reduced their gut microbes on day 15 but did not stop depolymerization because the Mn, Mw and size- average molecular weight (Mz) decreased. This confirmed that LDPE biodegradation in T. obscurus was independent of gut microbes as observed during previous PS degradation in T. molitor, suggesting that the intestinal digestive system could perform LDPE depolymerization. High-throughput sequencing revealed significant shifts in the gut microbial community during bran-fed and unfed conditions in response to LDPE feeding in both Tenebrio species. The respective predominant gut genera of Spiroplasma sp. and Enterococcus sp. were observed in LDPE-fed T. molitor and T. obscurus larvae.

Sustained release of hydroxycamptothecin after subcutaneous administration using a novel phospholipid complex-DepoFoam technology.

OBJECTIVE: In order to prolong the duration of drug in the circulation, multivesicular liposome (MVL, namely DepoFoam) was utilized as a sustained-release delivery system for hydroxycamptothecin (HCPT). METHODS: HCPT is insoluble in both water and physiological acceptable organic solvents; therefore, HCPT-phospholipid complex (HCPT-PCC) was prepared by solvent evaporation method to improve its liposolubility. In this study, preparation, characterization, in vitro release, and in vivo pharmacokinetics of HCPT-phospholipid complex-loaded MVLs (HCPT-MVLs) were investigated. RESULTS: The results showed that the average particle size of HCPT-MVL was 9 mum and the encapsulation efficiency was 90%. In addition, HCPT-MVLs could improve both in vitro release and in vivo pharmacokinetic behaviors of the original drug, with a sustained release of drugs over 5-6 days. CONCLUSION: These data suggested that by combined use of DepoFoam and phospholipid complex formation technique HCPT could be successfully entrapped into the MVLs, which might provide a paradigm for sustained release of insoluble drugs.

[Effect of oral implant restoration on dentition defect patients and its impact on TNF-α and IL-6 levels in gingival crevicular fluid].

PURPOSE: To investigate the clinical effects of oral implant restoration in patients with dentition defects and the its impact on tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) levels in gingival crevicular fluid. METHODS: Eighty-four patients with dentition defects from May 2017 to August 1919 in People's Hospital of Shanghai Pudong District were enrolled and randomly divided into control group (n=42) and experimental group (n=42). Patients in the control group were repaired by routine methods,while those in the experimental group were treated with oral implant restoration. The effect of restoration was evaluated 6 months after treatment. The levels of TNF-α, IL-6 in the gingival crevicular fluid and dental function were compared between the 2 groups. The data were analyzed using SPSS 18.0 software package. RESULTS: The levels of TNF-α and IL-6 in the experimental group and the control group after treatment were significantly higher than those before treatment (P<0.05). The levels of TNF-α and IL-6 in the experimental group were significantly lower than those in the control group 6 months after treatment (P<0.05). The scores of dental function in the experimental group and the control group were significantly higher than those before treatment (P<0.05). The scores of retention, speech, chewing and aesthetics of the experimental group 6 months after treatment were significantly higher than the control group (P<0.05). The incidence of infection, pricking, post and core loosing and teeth missing in the experimental group was significantly lower than that of the control group (P<0.05). CONCLUSIONS: In the treatment of patients with dentition defects, implant restoration has little effect on the levels of TNF-α and IL-6 in gingival crevicular fluid, which is helpful to improve dental function and reduce the incidence of postoperative complications. Therefore, it is worthwhile to be popularized in clinical application.

Growth inhibition of the pulmonary metastatic tumors by systemic delivery of the p27 kip1 gene using lyophilized lipid-polycation-DNA complexes.

BACKGROUND: p27(kip1) (p27), a cyclin-dependent kinase inhibitor (CDKI), is an important regulator of cell cycle progression and a putative tumor suppressor gene, and plays an important role in the inhibition of genesis and progression of several kinds of cancers. The present study aimed to evaluate the anti-tumor effects of p27 gene therapy by a nonviral gene delivery strategy on pulmonary metastatic tumors. METHODS: A recombinant plasmid composed of a p27 sequence was constructed and identified; it was then formulated with condensing agent protamine sulfate and entrapped into cationic liposomes. The resulting lipid-polycation-DNA complexes (LPD) were prepared into lyophilized forms. 5 x 10(5) of CT26 colorectal adenocarcinoma cells were inoculated into female Balb/c mice via the tail vein to establish lung tumor models. On the second day, mice were randomly divided into six groups for different intravenous treatments: phosphate-buffered saline, empty liposomes, naked pDNA, LPD-p27 kip1, Cisplatin (DPP), and LPD-p27 kip1 plus DPP, respectively. RESULTS: The growth curve of tumor and the growth inhibition rate of tumor showed that p27-LPDs could prolong the lifespan of the mice significantly, whereas the combination of p27-LPDs and DPP could further prolong the lifespan of the tumor-bearing animals. The histology of tumors examined by hematoxylin and eosin staining indicated that p27-LPDs had a stronger inhibition effect. Significant expression of p27 was detected in tumors using an immunohistochemical technique. CONCLUSIONS: Lyophilized LPD could be used as a potential in vivo gene delivery carrier for lung cancer gene therapy.

In vitro evaluation of the genotoxicity of a family of novel MeO-PEG-poly(D,L-lactic-co-glycolic acid)-PEG-OMe triblock copolymer and PLGA nanoparticles.

Despite the booming development of nanoparticle materials for pharmaceutical applications, studies on their genotoxicity are few. In our previous efforts to develop an intravenous nanoparticle material, a family of novel monomethoxy(polyethylene glycol)-poly(D,L-lactic-co-glycolic acid)-monomethoxy (PELGE) polymers was synthesized. The cytotoxicity and genotoxicity of nine kinds of selected blank PELGE and PLGA (poly(D,L-lactic and glycolic acid)) nanoparticles were evaluated using methyl thiazolyl tetrazolium (MTT), micronucleus (MN) and sister chromatid exchange (SCE) assays with or without the addition of a metabolic activation system (S9 mix), using Chinese hamster ovary (CHO) cells. The cytotoxicity of nanoparticles exhibited a dose-dependent response, with a concentration of 5 mg ml(-1) being the turning point. The frequencies of MN observed in samples treated with various nanoparticles were not statistically different from those seen in the negative controls in the presence or absence of the S9 mix. Also, no cell cycle delay was observed. The numbers of SCE per cell observed in samples treated with five kinds of PELGE nanoparticles were significantly greater than those found in the negative controls with or without the S9 mix. The discrepancies found in the two assays suggest that the five kinds of nanoparticles may produce only a weakly clastogenic response.

[Preparation of ASODN-protamine-HSA-PLGA nanoparticles and initial evaluation of their nucleus targeting property in vitro].

OBJECTIVES: To develop a novel non-viral gene delivery system-SODN-Protamine-HSA-PLGA (ASODN-P/H-PLGA-NP) and investigate its nucleus targeting potential in vitro. METHODS: ASODN-P/H-PLGA-NP was prepared by mixing the protamine sulfate and HSA. Then the PLGA nanoparticles were prepared using double-emulsion evaporation technique, followed by addition of ASODN to the prepared P/H complex. The morphology of ASODN-P/H-PLGA-NP was observed by transmission electron microscopy. The diameter, PDI, and surface charge of ASODN-P/H-PLGA-NP were measured by photo correlation spectroscopy (PCS). The encapsulation efficiency of ASODN was determined by double step method. The cytotoxicity of ASODN-P/H-PLGA-NP was investigated by MTT assays. The ability to enter the squamouse carcinoma: Hep-2 cell line and its nucleus targeting property were observed by confocal laser scanning microscope. RESULTS: The average diameter, PDI, zeta potential, and encapsulation efficiency of ASODN-P/H-PLGA-NP were 128 nm, 0.234, -23.3 mV, and 78.45%, respectively. ASODN-P/H-PLGA-NP could protect the ASODN from the shear force in the ultrasound process during preparation. ASODN-P/H-PLGA-NP couldenter Hep-2 cells and have certain level of nucleus targeting property. CONCLUSION: ASODN-P/H-PLGA-NP can be prepared easily with small particle sizes and low cytotoxicity, which might be employed as a good non-viral vector for applications in ASODN delivery to nucleus.