Polystyrene microplastics aggravate radiation-induced intestinal injury in mice.

Radiotherapy is a common treatment for abdominal and pelvic tumors, while the radiation-induced intestinal injury (RIII) is one of the major side-effects of radiotherapy, which reduces the life quality and impedes the treatment completion of cancer patients. Previous studies have demonstrated that environmental pollutant microplastics led to various kinds of injury in the gut, but its effects on RIII are still uncovered. In this study, we fed the C57BL/6J mice with distilled water or 50 µg/d polystyrene microplastics (PSMPs) for 17 days and exposed the mice to total abdominal irradiation (TAI) at day 14. Then the severity of RIII was examined by performing histopathological analysis and microbial community analysis. The results demonstrated that PSMPs significantly aggravated RIII in small intestine rather than colon of mice upon TAI. PSMPs increased levels of the histopathological damage and the microbial community disturbance in mice small intestine, shown by the overabundance of Akkermansiaceae and the decrease of microflora including Lactobacillaceae, Muribaculaceae and Bifidobacteriaceae. In conclusion, our results suggested that more microplastics exposure might led to more severe RIII, which should be considered in patients' daily diet adjustment and clinical radiotherapy plan evaluation. Furthermore, this study also called for the further researches to uncover the underlying mechanism and develop novel strategies to attenuate RIII in mice intestine.

Electrospun polylactic acid nanofibers membrane with copper ion-loaded clay nanotubes for fresh-keeping packaging.

The plastics derived from fossil fuels for food packaging results in serious environmental problems. Developing environment-friendly materials for food packaging is urgent and essential. In this study, polylactic acid (PLA) composite nanofibers membranes were prepared with good biocompatibility and antibacterial property. Cu2+ loaded in the natural halloysite nanotubes (HNTs) was used for the antibacterial agent. Cu2+ was loaded in the HNTs and was confirmed by the X-ray photoelectron spectroscopy (XPS). PLA nanofibers with different HNTs-Cu content were continuous nanofibers with the nanoscale range. HNTs-Cu entered into the nanofiber successfully. Thermal analysis results showed composite nanofibers had good thermal stability. Composite nanofiber membranes had the good hydrophobic property. HNTs-Cu improved the mechanical property of composite nanofibers than pure PLA nanofibers. Tensile strength and elasticity modulus of composite nanofibers with 4 % HNTs-Cu content were the most outstanding. L929 cells were cultured on the nanofiber membranes for biocompatibility evaluation. Cell viability of nanofiber membranes was above the 90 %. Cell live/dead staining results showed L929 cells was seldom dead on the nanofiber membranes. PLA/HNTs-Cu nanofiber membranes exhibited excellent antibacterial effects on S. aureus and E. coli. The inhibitory rates against S. aureus and E. coli were 98.31 % and 97.80 % respectively. The fresh-keeping effects of nanofiber membranes were evaluated by the strawberry preservation. Strawberries covered by nanofiber membranes exhibited better appearance, lower weight loss and higher firmness than control, PLA and PLA/HNTs groups. It promised that PLA/HNTs-Cu composite nanofiber membranes have the significant potential application for active food packaging.

Enhanced antitumor response mediated by the codelivery of paclitaxel and adenoviral vector expressing IL-12.

It has been well-established that chemo-immunotherapy using cytotoxic drugs and appropriate cytokines offers a promising approach for the treatment of neoplastic diseases. In view of this, to improve melanoma treatment effect, our study developed a new codelivery system (AL/Ad5/PTX) that paclitaxel (PTX) and adenovirus encoding for murine interleukin-12 (Ad5-mIL-12) were incorporated into anionic liposomes (AL). First, AL/Ad5/PTX complexes were prepared by incorporating Ad5 into anionic PTX liposomes using calcium-induced phase change. Second, the size distribution and zeta potential of AL/Ad5/PTX were investigated. Third, the results of in vitro transduction assays showed that PTX introduced into AL/Ad-luc or AL/Ad5-mIL-12 highly enhanced gene transduction efficiency in B16 cells than naked Ad5 or AL/Ad complexes while it had no comparability in A549 cells. Finally, a melanoma-bearing mouse model was established to assess the antitumor effect. Tumor growth inhibition and prolonged survival time, accompanied by increased mIL-12 or interferon-γ (IFN-γ) expression levels in serum or tumor sites, were observed in mice treated with AL/Ad5-mIL-12/PTX, as compared with those treated with either AL/Ad5-mIL-12 or AL/PTX. In conclusion, these results suggested that codelivery of Ad5-mIL-12 and PTX incorporated into AL could be a relatively efficient strategy for the treatment of melanoma.

Enhanced ectopic bone formation by strontium-substituted calcium phosphate ceramics through regulation of osteoclastogenesis and osteoblastogenesis.

To explore how strontium influences osteoclastogenesis and osteoblastogenesis during material-induced ectopic bone formation, porous strontium-substituted biphasic calcium phosphate (Sr-BCP) and BCP ceramics with equivalent pore structures and comparable grain size and porosity were prepared. In vitro results showed that compared with BCP, Sr-BCP inhibited the osteoclastic differentiation of osteoclast precursors by delaying cell fusion, down-regulating the expression of osteoclast marker genes, and reducing the activity of osteoclast specific proteins, possibly due to the activated ERK signaling pathway but the suppressed p38, JNK and AKT signaling pathways. Meanwhile, Sr-BCP promoted the osteogenic differentiation of mesenchymal stem cells (MSCs) by up-regulating the osteogenic gene expression. Sr-BCP also mediated the expression of important osteoblast-osteoclast coupling factors, as evidenced by the increased Opg/Rankl ratio in mMSCs, and the reduced Rank expression and enhanced EphrinB2 expression in osteoclast precursors. Similar results were observed in an in vivo study based on a murine intramuscular implantation model. The sign of ectopic bone formation was only seen in Sr-BCP at 8 weeks. Compared to BCP, Sr-BCP obviously hindered the formation of TRAP- and CTSK-positive multinucleated osteoclast-like cells during the early implantation time up to 6 weeks, which is consistent with the in vivo PCR results. This suggested that Sr-BCP could clearly accelerate the ectopic bone formation by promoting osteogenesis but suppressing osteoclastogenesis, which might be closely related to the expression of osteoblast-osteoclast coupling factors regulated by Sr2+. These findings may help in the design and fabrication of smart bone substitutes with the desired potential for bone regeneration through modulating both osteoclastic resorption and osteoblastic synthesis.

Preparation of an aminophenylboronic acid and N-isopropyl acrylamide copolymer functionalized stationary phase for mixed-mode chromatography.

A novel stationary phase co-modified with N-isopropyl acrylamide (NIPAM) and 3-aminophenylboronic acid copolymer on the silica was synthesized through atom transfer radical polymerization (ATRP) reaction for performing mixed-mode and boronate affinity chromatography. The prepared functionalized silica was characterized using Fourier transform infrared spectrometry (FT-IR), elemental analysis (EA) and thermogravimetric analysis (TGA), scanning electron micrographs (SEM) and Brunauer-Emmett-Teller (BET) measurements. The prepared column named Sil-PBA-NIPAM showed great separation performance for hydrophobic, hydrophilic, positional isomer, acidic and alkaline compounds. Besides, the mixture of cis-diol and non-cis-diol compounds was used to prove that the developed column also has potential to capture and enrich cis-diol compounds. The prepared column possesses merits of time-saving, high selectivity to cis-diol compounds and molecular-planarity selectivity compared with two commercial single-mode columns. The theoretical plates of material can reach to 57472 and the column has good hydrolysis stability and batch-to-batch reproducibility. In summary, the prepared column possesses good hydrophilicity, hydrophobicity, molecular-planarity selectivity and boronate affinity abilities for the analysis of various compounds.

A poly(beta-amino ester) activates macrophages independent of NF-κB signaling.

Nucleic acid delivery vehicles are poised to play an important role in delivering gene therapy for vaccines and immunotherapies, and in delivering nucleic acid based adjuvants. A number of common polymeric delivery vehicles used in nucleic acid delivery have recently been shown to interact with immune cells and directly stimulate immunogenic responses, particularly in particle form. Poly(beta-amino esters) were designed for nucleic acid delivery and have demonstrated promising performance in a number of vaccine and therapeutic studies. Yet, little work has characterized the mechanisms by which these polymers activate immune cells. Here we demonstrate that a poly(beta-amino ester) activates antigen presenting cells in soluble and particulate forms, and that these effects are independent of TLR signaling pathways. Moreover, we show the polymers induce activation independent of NF-κB signaling, but do activate IRF, an important innate inflammatory pathway. New knowledge linking physicochemical features of poly(beta-amino esters) or other polymeric carriers to inflammatory mechanisms could support more rational design approaches for vaccines and immunotherapies harnessing these materials. SIGNIFICANCE STATEMENT: The last several years have brought exciting work exploring biomaterials as delivery vehicles for immunotherapies, vaccines, and gene therapies. However, a gap remains between the striking finding that many biomaterials exhibit intrinsic immunogenic features, and the specific structural properties that drive these responses. The results in the current study indicate PBAEs cause macrophage activation by pathways that are distinct from pathways activated by common vaccine and immunotherapies components, such as toll-like receptor agonists. Thus, the work reveals new mechanistic details that can be exploited in investigating other materials, and to support more rational design of future biomaterial vaccines and immunotherapy carriers.

Advanced manufacturing of microdisk vaccines for uniform control of material properties and immune cell function.

The continued challenges facing vaccines in infectious disease and cancer highlight a need for better control over the features of vaccines and the responses they generate. Biomaterials offer unique advantages to achieve this goal through features such as controlled release and co-delivery of antigens and adjuvants. However, many synthesis strategies lead to particles with heterogeneity in diameter, shape, loading level, or other properties. In contrast, advanced manufacturing techniques allow precision control of material properties at the micro- and nano-scale. These capabilities in vaccines and immunotherapies could allow more rational design to speed efficient design and clinical translation. Here we employed soft lithography to generate polymer microdisk vaccines with uniform structures and tunable compositions of vaccine antigens and toll like receptor agonists (TLRas) that serve as molecular adjuvants. Compared to conventional PLGA particles formed by emulsion, microdisks provided a dramatic improvement in the consistency of properties such as diameter. During culture with primary dendritic cells (DCs) from mice, microdisks were internalized by the cells without toxicity, while promoting co-delivery of antigen and TLRa to the same cell. Analysis of DC surface activation markers by flow cytometry revealed microdisk vaccines activated dendritic cells in a manner that depended on the level of TLRa, while antigen processing and presentation depended on the amount of antigen in the microdisks. Together, this work demonstrates the use of advanced manufacturing techniques to produce uniform vaccines that direct DC function depending on the composition in the disks.

Tailoring polymeric hybrid micelles with lymph node targeting ability to improve the potency of cancer vaccines.

It has been widely accepted that lymph nodes (LNs) are critical targets of cancer vaccines and particles sized between 10 and 100 nm with a neutral or negative surface charge are preferred for lymphatic transfer after subcutaneous or intradermal injection. However their limited uptake by antigen presenting cells (APCs) and inadequate retention within LNs undoubtedly restrains their strength on activating T cell immunity. Here, we address this issue by tailoring the physicochemical properties of polymeric hybrid micelles (HMs), which are self-assembled from two amphiphilic diblock copolymers, poly-(ethylene glycol) phosphorethanolamine (PEG-PE) and polyethylenimine-stearic acid conjugate (PSA) via hydrophobic and electrostatic interactions. We successfully encapsulate melanoma antigen peptide Trp2 and Toll-like receptor-9 (TLR-9) agonist CpG ODN into HMs with a size of sub-30 nm. Their surface characteristics which are found closely related to their in vivo kinetics can be modulated by simply adjusting the molar ratio of PEG-PE and PSA. Our results demonstrated the optimized HMs with an equal mol of PEG-PE and PSA can potently target proximal LNs where their cargos are efficiently internalized by DCs. Furthermore, HMs mediated Trp2/CpG delivery system greatly expands antigen specific cytotoxic T lymphocytes (CTLs) and offers a strong anti-tumor effect in a lung metastatic melanoma model.

Effects of Polyamidoamine Dendrimers on a 3-D Neurosphere System Using Human Neural Progenitor Cells.

The practical application of engineered nanomaterials or nanoparticles like polyamidoamine (PAMAM) dendrimers has been promoted in medical devices or industrial uses. The safety of PAMAM dendrimers needs to be assessed when used as a drug carrier to treat brain disease. However, the effects of PAMAM on the human nervous system remain unknown. In this study, human neural progenitor cells cultured as a 3D neurosphere model were used to study the effects of PAMAM dendrimers on the nervous system. Neurospheres were exposed to different G4-PAMAM dendrimers for 72 h at concentrations of 0.3, 1, 3, and 10 µg/ml. The biodistribution was investigated using fluorescence-labeled PAMAM dendrimers, and gene expression was evaluated using microarray analysis followed by pathway and network analysis. Results showed that PAMAM dendrimer nanoparticles can penetrate into neurospheres via superficial cells on them. PAMAM-NH2 but not PAMAM-SC can inhibit neurosphere growth. A reduced number of MAP2-positive cells in flare regions were inhibited after 10 days of differentiation, indicating an inhibitory effect of PAMAM-NH2 on cell proliferation and neuronal migration. A microarray assay showed 32 dendrimer toxicity-related genes, with network analysis showing 3 independent networks of the selected gene targets. Inducible immediate early gene early growth response gene 1 (Egr1), insulin-like growth factor-binding protein 3 (IGFBP3), tissue factor pathway inhibitor (TFPI2), and adrenomedullin (ADM) were the key genes in each network, and the expression of these genes was significantly down regulated. These findings suggest that exposure of neurospheres to PAMAM-NH2 dendrimers affects cell proliferation and migration through pathways regulated by Egr1, IGFBP3, TFPI2, and ADM.

Cationic micelle delivery of Trp2 peptide for efficient lymphatic draining and enhanced cytotoxic T-lymphocyte responses.

Neutral particles 20-45 nm in diameter showed potential as tumor antigen vectors because they targeted the draining lymph nodes after subcutaneous injection. However, they were weakly immune-stimulatory and could also spread throughout the body, raising the risk of systemic toxicity. Here we explored whether incorporating positively charged amphiphilic polymers into micelles improves their site specificity and immunogenicity. Cationic polyethylenimine (2k)-stearic acid (PSA) micelles were loaded with the melanoma antigen peptide Trp2; they showed an average size of 28.7±8.2 nm and an encapsulation efficiency of 99.21±5.38%. Empty PSA micelles acted as a robust adjuvant in vitro, promoting maturation, proliferation and migration of bone marrow-derived dendritic cells in a dose-dependent manner. After subcutaneous injection into mice, Trp2-loaded PSA micelles accumulated preferentially in the medulla and paracortex of the draining lymph nodes and were present at negligible levels in the systemic circulation. Mice immunized with Trp2-loaded PSA micelles showed significantly higher Trp2-specific cytotoxic T lymphocyte activity than mice immunized with free Trp2 or a mixture of Trp2 and empty PSA micelles. In a B16-F10 murine melanoma model, Trp2-loaded PSA micelles inhibited tumor growth significantly more than did free Trp2 and PSA micelles caused less systemic toxicity. These findings suggest that cationic PSA micelles loaded with Trp2 may be a potential approach for melanoma immunotherapy.

Protection of adenovirus from neutralizing antibody by cationic PEG derivative ionically linked to adenovirus.

BACKGROUND: The generation of anti-adenovirus neutralizing antibody (NAb) in humans severely restricts the utilization of recombinant adenovirus serotype 5 (Ad5) vectors in gene therapy for a wide range of clinical trials. To overcome this limitation, we ionically complexed Ad5 with a newly synthesized copolymer, which we called APC, making an adenovirus shielded from NAb. METHODS: APC, a cationic polyethylene glycol derivative, was synthesized via two steps of ring-opening copolymerization of ethylene oxide and allyl glycidyl ether, followed by the addition of 2-mercaptoethylamine. The copolymer or the control PEI-2k was ionically complexed to anionic Ad5 in 5% glucose, and in vitro transduction assays were carried out in coxsackievirus and adenovirus receptor-positive cells (A549) and coxsackievirus and adenovirus receptor-negative cells (B16 and SKOV3). The physical properties and morphology of adenovirus alone or the complexes were investigated respectively by zeta potential, size distribution, and transmission electron microscopy image. Then cytotoxicity of APC was examined using 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assays. Finally, the ability of APC to protect adenovirus from NAb was evaluated by transfection assays after a neutralizing effect. RESULTS: APC was successfully synthesized and showed a low cytotoxicity. Positively charged Ad5/APC exhibited slightly increased diameter (130.2 ± 0.60 nm) than naked Ad5 (115.6 ± 5.46 nm) while Ad5/PEI-2k showed severe aggregation (1382 ± 79.9 nm). Ad5/APC achieved a gene transfection level as high as Ad5/PEI-2k in A549 or B16 cells, and significantly higher than Ad5/PEI-2k in SKOV3 cells. Most importantly, after the exposure to the neutralizing antibody, naked Ad5 and Ad5/PEI-2k exhibited poor gene expression while Ad5/APC still showed significantly efficient gene expression. CONCLUSION: Our results demonstrated that Ad5/APC complex offered good protection for Ad5 against NAb in vitro and suggested a potential strategy of resistance to NAb in vivo.