Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Microbiome ; 12(1): 89, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38745230

RESUMO

BACKGROUND: Non-toxic approaches to enhance radiotherapy outcomes are beneficial, particularly in ageing populations. Based on preclinical findings showing that high-fibre diets sensitised bladder tumours to irradiation by modifying the gut microbiota, along with clinical evidence of prebiotics enhancing anti-cancer immunity, we hypothesised that dietary fibre and its gut microbiota modification can radiosensitise tumours via secretion of metabolites and/or immunomodulation. We investigated the efficacy of high-fibre diets combined with irradiation in immunoproficient C57BL/6 mice bearing bladder cancer flank allografts. RESULT: Psyllium plus inulin significantly decreased tumour size and delayed tumour growth following irradiation compared to 0.2% cellulose and raised intratumoural CD8+ cells. Post-irradiation, tumour control positively correlated with Lachnospiraceae family abundance. Psyllium plus resistant starch radiosensitised the tumours, positively correlating with Bacteroides genus abundance and increased caecal isoferulic acid levels, associated with a favourable response in terms of tumour control. Psyllium plus inulin mitigated the acute radiation injury caused by 14 Gy. Psyllium plus inulin increased caecal acetate, butyrate and propionate levels, and psyllium alone and psyllium plus resistant starch increased acetate levels. Human gut microbiota profiles at the phylum level were generally more like mouse 0.2% cellulose profiles than high fibre profiles. CONCLUSION: These supplements may be useful in combination with radiotherapy in patients with pelvic malignancy. Video Abstract.


Assuntos
Fibras na Dieta , Suplementos Nutricionais , Microbioma Gastrointestinal , Inulina , Camundongos Endogâmicos C57BL , Psyllium , Neoplasias da Bexiga Urinária , Animais , Camundongos , Microbioma Gastrointestinal/efeitos dos fármacos , Inulina/administração & dosagem , Neoplasias da Bexiga Urinária/radioterapia , Neoplasias da Bexiga Urinária/patologia , Humanos , Feminino , Lesões por Radiação/prevenção & controle , Intestinos/microbiologia , Intestinos/efeitos da radiação , Linfócitos T CD8-Positivos
2.
Int J Biol Macromol ; 238: 124087, 2023 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-36940766

RESUMO

Gas therapy based on nitric oxide (NO) has emerged as a potential therapeutic approach for cancer, and in conjunction with multi-mode combination therapy, offers new possibilities for achieving significant hyperadditive effects. In this study, an integrated AI-MPDA@BSA nanocomposite for diagnosis and treatment was constructed for PDA based photoacoustic imaging (PAI) and cascade NO release. Natural NO donor L-arginine (L-Arg) and photosensitizer (PS) IR780 were loaded into mesoporous polydopamine (MPDA). Bovine serum albumin (BSA) was conjugated to the MPDA to increase the dispersibility and biocompatibility of the nanoparticles, as well as to serve as a gatekeeper controlling IR780 release from the MPDA pores. The AI-MPDA@BSA produced singlet oxygen (1O2) and converted it into NO through a chain reaction based on L-Arg, enabling a combination of photodynamic therapy and gas therapy. Moreover, due to the photothermal properties of MPDA, the AI-MPDA@BSA performed good photothermal conversion, which allowed photoacoustic imaging. As expected, both in vitro and in vivo studies have confirmed that the AI-MPDA@BSA nanoplatform has a significant inhibitory effect on cancer cells and tumors, and no apparent systemic toxicity or side effects were detected during the treatment period.


Assuntos
Nanopartículas , Neoplasias , Humanos , Fototerapia/métodos , Soroalbumina Bovina , Óxido Nítrico , Neoplasias/terapia
3.
Colloids Surf B Biointerfaces ; 210: 112261, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34902711

RESUMO

In this work, a novel layered double hydroxide (LDH)-based multifunctional nanoplatform was built for synergistic photothermal therapy (PTT)/chemotherapy. The platform was modified using the peptide B3int to target cancer cells with overexpression of integrin αvß3. Indocyanine green (ICG) and doxorubicin (DOX) were loaded into the nanocarrier (LDH-PEG-B3int NPs) to form a system having a high drug loading (18.62%) and a remarkable photothermal conversion efficiency of 25.38%. It also showed pH-responsive and near-infrared (NIR)-triggered DOX release. In vitro and in vivo studies indicated that the anti-tumor activity of the combined delivery system was significantly higher than that of a single delivery system. This co-delivery nanosystem may be helpful for future application in the clinical treatment of cancer.


Assuntos
Hipertermia Induzida , Nanopartículas , Doxorrubicina/farmacologia , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Hidróxidos , Fototerapia , Terapia Fototérmica
4.
Eur J Nutr ; 60(4): 2063-2075, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33015732

RESUMO

PURPOSE: Farmed fish are increasingly raised on feeds containing vegetable oils, which affects their composition and possibly health properties. We investigated the effects of consuming farmed salmon, raised on different feeding regimes, on nutrient status and health outcomes in healthy subjects. METHODS: Salmon were grown on feeds containing mainly fish oil (FO) or rapeseed oil (RO), resulting in an eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) content of fillets of 2.1 or 0.9 g/100 g, respectively. In a randomized parallel controlled trial, 51 healthy subjects were allocated to consume 2 portions/week of FO salmon (n = 17), RO salmon (n = 17) or no additional salmon (Control, n = 17) as part of their habitual diet, for 18 weeks. We collected blood at 0, 9 and 18 weeks to measure omega-3 index (O3I) in red blood cells, plasma markers of cardiovascular risk, serum 25(OH)-vitamin D3 (25(OH)D3) and plasma trace elements. RESULTS: After 18 weeks, O3I was similarly increased in subjects consuming 2 portions/week of FO or RO salmon compared to control (both p < 0.05). Serum 25(OH)D3 was significantly higher, whereas plasma triacylglycerols were significantly lower in subjects consuming RO salmon compared to control (both p < 0.05). Heart rate was significantly lower in subjects consuming FO salmon after 9 weeks, compared to control (p < 0.01). Salmon consumption did not affect other markers. CONCLUSION: Consuming two portions/week of salmon raised on rapeseed oil rather than fish oil increased the O3I and vitamin D status, and decreased plasma triacylglycerols. These outcomes endorse opportunities for developing more sustainable feeds within aquaculture food systems. CLINICAL TRIAL REGISTRY: This trial was registered at clinicaltrials.gov as NCT01916434.


Assuntos
Brassica napus , Salmão , Animais , Ácidos Docosa-Hexaenoicos , Ácido Eicosapentaenoico , Óleos de Peixe , Humanos , Óleo de Brassica napus , Alimentos Marinhos
5.
Carbohydr Polym ; 247: 116672, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829800

RESUMO

Nanocomposites as "stevedores" for co-delivery of multidrugs hold great promise in addressing the drawbacks of traditional cancer chemotherapy. In this work, our strategy presents a new avenue for the stepwise release of two co-delivered agents into the tumor cells. The hybrid nanocomposite consists of a pH-responsive chitosan (CS), a thermosensitive poly(N-vinylcaprolactam) (PNVCL) and a functionalized cell-penetrating peptide (H6R6). Doxorubicin (DOX) and oleanolic acid (OA) are loaded into the nanocomposite (H6R6-CS-g-PNVCL). The system displayed a suitable size (∼190 nm), a high DOX loading (13.2 %) and OA loading efficiency (7.3 %). The tumor microenvironment triggered the nanocomposite to be selectively retained in tumor cells, then releasing the drugs. Both in vitro and in vivo studies showed a significant enhancement in antitumor activity of the co-delivered system in comparison to mono-delivery. This approach which relies on redox, pH and temperature effects utilizing co-delivery nanosystems may be beneficial for future applications in cancer chemotherapy.


Assuntos
Apoptose , Quitosana/química , Doxorrubicina/administração & dosagem , Sistemas de Liberação de Medicamentos , Nanocompostos/administração & dosagem , Ácido Oleanólico/administração & dosagem , Neoplasias Ovarianas/tratamento farmacológico , Animais , Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/farmacocinética , Proliferação de Células , Doxorrubicina/farmacocinética , Portadores de Fármacos/química , Feminino , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Nanocompostos/química , Ácido Oleanólico/farmacocinética , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Distribuição Tecidual , Células Tumorais Cultivadas , Microambiente Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Adv Healthc Mater ; 9(2): e1901307, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31814332

RESUMO

A nanoplatform that integrates diagnostic and therapeutic functions with intrinsic tumor microenvironment-responsive biodegradability is highly desired. Herein, a biodegradable nanotheranostic agent based on hollow mesoporous organosilica nanoparticles (HMONs), followed by encapsulating of heat shock protein 90 (Hsp 90) inhibitor is described. Then, the pore-engineering including gating with bovine serum albumin-iridium oxide nanoparticles (BSA-IrO2 ) and conjugation of polyethylene glycol (PEG) is conducted to yield 17AAG@HMONs-BSA-IrO2 -PEG (AHBIP) nanotheranostics for multimode computed tomography (CT)/photoacoustic (PA) imaging-guided photodynamic therapy (PDT) and low-temperature photothermal therapy (PTT). Such nanoplatforms show extraordinary photothermal conversion efficiency, high cargo loading (35.4% for 17AAG), and stimuli-responsive release of 17AAG for inhibition of Hsp90, which induces cell apoptosis at low-temperatures (≈41 °C). Also, the IrO2 simultaneously endows the nanotheranostics with catalytic activity in triggering the decomposition of H2 O2 into O2 and thus reducing the tumor hypoxia, as well as protecting normal tissues against H2 O2 -induced inflammation. AHBIP shows good photocatalysis activity for PDT as a result of the generation of superoxide anion by laser irradiation. The resulting AHBIP-mediated synergistic PTT/PDT offers an outstanding therapeutic outcome both in vitro and in vivo. Overall, the incorporation of the BSA-IrO2 and biodegradable HMONs into one nanoplatform has great potential for clinical applications.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Benzoquinonas/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Lactamas Macrocíclicas/administração & dosagem , Nanopartículas/química , Nanomedicina Teranóstica/métodos , Animais , Anti-Inflamatórios não Esteroides/química , Benzoquinonas/farmacocinética , Materiais Biocompatíveis/química , Neoplasias da Mama/patologia , Neoplasias da Mama/terapia , Linhagem Celular , Feminino , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Humanos , Peróxido de Hidrogênio/química , Irídio/química , Lactamas Macrocíclicas/farmacocinética , Camundongos Endogâmicos C57BL , Camundongos Nus , Oxigênio/farmacocinética , Técnicas Fotoacústicas , Fotoquimioterapia/métodos , Polietilenoglicóis/química , Soroalbumina Bovina/química , Superóxidos/metabolismo , Nanomedicina Teranóstica/instrumentação , Tomografia Computadorizada por Raios X , Microambiente Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Colloids Surf B Biointerfaces ; 185: 110585, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31683203

RESUMO

Synergistic tumor treatment has recently attracted more and more attention due to its remarkable therapeutic effect. Herein, a multifunctional drug delivery system based on hyaluronic acid (HA) targeted dual stimulation responsive MoS2 nanosheets (HA-PEI-LA-MoS2-PEG, HPMP) for active interaction with CD44 receptor positive MCF-7 cells is reported. Melanin (Mel), a new type of photothermal agent and doxorubicin (DOX) are both loaded onto the HPMP nanocomposite and can be released by mild acid or hyperthermia. The prepared HPMP nanocomposite has a uniform hydrodynamic diameter (104 nm), a high drug loading (944.3 mg.g-1 HPMP), a remarkable photothermal effect (photothermal conversion efficiency: 55.3%) and excellent biocompatibility. The DOX release from HPMP@(DOX/Mel) can be precisely controlled by the dual stimuli of utilizing the acidic environment in the tumor cells and external laser irradiation. Meanwhile, loading of Mel onto the surface can enhance the photothermal effect of the MoS2 nanosheets. In vitro experiments showed that the HPMP@(DOX/Mel) nanoplatform could efficiently deliver DOX into MCF-7 cells and demonstrated enhanced cytotoxicity compared to that of the non-targeted nanoplatform. In vivo experiments in a breast cancer model of nude mice further confirmed that the HPMP@(DOX/Mel) significantly inhibited tumor growth under near infrared (NIR) laser irradiation, which is superior to any single therapy. In summary, this flexible nanoplatform, based on multi-faceted loaded MoS2 nanosheets, exhibits considerable potential for efficient pH/NIR-responsive targeted drug delivery and chemo-photothermal synergistic tumor therapy.


Assuntos
Neoplasias da Mama/terapia , Dissulfetos/química , Doxorrubicina/farmacologia , Sistemas de Liberação de Medicamentos , Hipertermia Induzida , Molibdênio/química , Nanocompostos/química , Fototerapia , Animais , Antibióticos Antineoplásicos/farmacologia , Apoptose , Neoplasias da Mama/patologia , Proliferação de Células , Doxorrubicina/química , Liberação Controlada de Fármacos , Feminino , Humanos , Raios Infravermelhos , Camundongos , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
8.
J Biomed Nanotechnol ; 15(7): 1415-1431, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31196347

RESUMO

The fabrication of theranostic nanoplatforms which combine diagnostic and therapeutic functions have become an emerging approach for personal nanomedicine. Herein, a multifunctional nanoplatform consisting of A7R peptide (ATWLPPR) conjugated hollow mesoporous silica nanoparticles decorated with Ag2S nanodots (Ag2S@HMSs-A7R) has been developed as an efficient theranostic agent for simultaneous photoacoustic (PA) imaging and near-infrared fluorescence imaging (NIRF)-guided targeted chemotherapy and photothermal therapy against human breast cancer MDA-MB-231 cells. The design of Ag2S doped HMSs by in situ controlled growth of ultrasmall Ag2S nanodots in the mesopores of HMSs. The synthesized multifunctional nanoplatform exhibits high doxorubicin (DOX) loading capability (451 mg/g) and can be precisely controlled by glutathione (GSH), acidic environment and external laser irradiation. Thanks to the strong tunable NIR absorbance of Ag2S, the nanoplatform produce effective photoacoustic capacity and superb photothermal conversion under light irradiation, thereby exhibiting sufficient in vivo fluorescence and photoacoustic signals as well as desirable photothermal therapeutic performance. Importantly, A7R peptide can selectively bind the Neuropilin-1 (NRP-1) receptor which overexpressed by the MDA-MB-231 cells. The achieved Ag2S@HMSs-A7R possess ideal imaging capability for both PA and NIRF imaging in vivo, and the anti-tumor effect of Ag2S@HMSs(DOX)-A7R was studied in vitro and in vivo, showing remarkable synergistic chemo-photothermal effect (combination index, CI < 1). Over all, the strategy of utilizing triple-responsive nanocarriers presents a highly promising potential as an efficient method for cancer theranostics.


Assuntos
Neoplasias , Doxorrubicina , Humanos , Peptídeos , Dióxido de Silício , Nanomedicina Teranóstica
9.
ACS Appl Mater Interfaces ; 10(49): 42115-42126, 2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30462492

RESUMO

Noninvasive physical treatment with relatively low intensity stimulation and the development of highly efficient anticancer medical strategy are still desirable for cancer therapy. Herein a versatile, biodegradable, hollow mesoporous organosilica nanocapsule (HMONs) nanoplatform that is capped by the gemcitabine (Gem) molecule through a pH-sensitive acetal covalent bond is designed. The fabricated nanocapsule exhibits desirable small molecule release at the tumor tissues/cell sites and shows a reduced risk for drug accumulation. After loading indocyanine green (ICG), the heat-shock protein 90 (Hsp 90) inhibitor, and 17AAG and modification with polyethylene glycol (NH2-PEG), the resulting ICG-17AAG@HMONs-Gem-PEG exhibited a precisely controlled release of ICG and 17AAG and low-temperature photothermal therapy (PTT) (∼41 °C) with excellent tumor destruction efficacy. In addition, ICG loading conferred the nanoplatform with near-infrared fluorescence imaging (FL) and photoaccoustic (PA) imaging capability. In short, this work not only presents a smart drug self-controlled nanoplatform with pH-responsive payload release and theranostic performance but also provides an outstanding low-temperature PTT strategy, which is highly valid in the inhibition of cancer cells with minimal damage to the organism. Therefore, this research provides a paradigm that has a chemodrug-gated HMONs-based theranostic nanoplatform with intrinsic biodegradability, multimodal imaging capacity, high low-temperature PTT/chemotherapy efficacy, and reduced systemic toxicity.


Assuntos
Doxorrubicina , Hipertermia Induzida , Verde de Indocianina , Nanocápsulas , Compostos de Organossilício , Fototerapia , Animais , Linhagem Celular Tumoral , Doxorrubicina/química , Doxorrubicina/farmacocinética , Doxorrubicina/farmacologia , Humanos , Verde de Indocianina/química , Verde de Indocianina/farmacocinética , Verde de Indocianina/farmacologia , Camundongos , Camundongos Nus , Nanocápsulas/química , Nanocápsulas/uso terapêutico , Compostos de Organossilício/química , Compostos de Organossilício/farmacocinética , Compostos de Organossilício/farmacologia , Polietilenoglicóis/química , Polietilenoglicóis/farmacocinética , Polietilenoglicóis/farmacologia
10.
Drug Deliv ; 25(1): 1275-1288, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29847177

RESUMO

Nanoparticles and macromolecular carriers have been widely used to increase the efficacy of chemotherapeutics, largely through passive accumulation provided by their enhanced permeability and retention effect. However, the therapeutic efficacy of nanoscale anticancer drug delivery systems is severely truncated by their low tumor-targetability and inefficient drug release at the target site. Here, the design and development of novel l-peptide functionalized dual-responsive nanoparticles (l-CS-g-PNIPAM-PTX) for active targeting and effective treatment of GRP78-overexpressing human breast cancer in vitro and in vivo are reported. l-CS-g-PNIPAM-PTX NPs have a relative high drug loading (13.5%) and excellent encapsulation efficiency (74.3%) and an average diameter of 275 nm. The release of PTX is slow at pH 7.4 and 25 °C but greatly accelerated at pH 5.0 and 37 °C. MTT assays and confocal experiments showed that the l-CS-g-PNIPAM-PTX NPs possessed high targetability and antitumor activity toward GRP78 overexpressing MDA-MB-231 human breast cancer cells. As expected, l-CS-g-PNIPAM-PTX NPs could effectively treat mice bearing MDA-MB-231 human breast tumor xenografts with little side effects, resulting in complete inhibition of tumor growth and a high survival rate over an experimental period of 60 days. These results indicate that l-peptide-functionalized acid - and thermally activated - PTX prodrug NPs have a great potential for targeted chemotherapy in breast cancer.


Assuntos
Apoptose/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/química , Proteína Básica da Mielina/química , Nanopartículas/química , Paclitaxel/administração & dosagem , Paclitaxel/química , Fragmentos de Peptídeos/química , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos/efeitos dos fármacos , Chaperona BiP do Retículo Endoplasmático , Feminino , Humanos , Camundongos , Camundongos Nus , Pró-Fármacos/administração & dosagem , Pró-Fármacos/química
11.
Eur J Nutr ; 57(5): 1855-1872, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28560503

RESUMO

PURPOSE: Low fruit and vegetable consumption is linked with an increased risk of death from vascular disease and cancer. The benefit of eating fruits and vegetables is attributed in part to antioxidants, vitamins and phytochemicals. Whether increasing intake impacts on markers of disease remains to be established. This study investigates whether increasing daily intake of fruits, vegetables and juices from low (approx. 3 portions), to high intakes (approx. 8 portions) impacts on nutritional and clinical biomarkers. Barriers to achieving the recommended fruit and vegetable intakes are also investigated. METHOD: In a randomised clinical trial, the participants [19 men and 26 women (39-58 years)] with low reported fruit, juice and vegetable intake (<3 portions/day) were randomised to consume either their usual diet or a diet supplemented with an additional 480 g of fruit and vegetables and fruit juice (300 ml) daily for 12 weeks. Nutritional biomarkers (vitamin C, carotenoids, B vitamins), antioxidant capacity and genomic stability were measured pre-intervention, at 4-, 8- and 12 weeks throughout the intervention. Samples were also taken post-intervention after a 6-week washout period. Glucose, homocysteine, lipids, blood pressure, weight and arterial stiffness were also measured. Intake of fruit, fruit juice and vegetables was reassessed 12 months after conducting the study and a questionnaire was developed to identify barriers to healthy eating. RESULTS: Intake increased significantly in the intervention group compared to controls, achieving 8.4 portions/day after 12 weeks. Plasma vitamin C (35%), folate (15%) and certain carotenoids [α-carotene (50%) and ß-carotene (70%) and lutein/zeaxanthin (70%)] were significantly increased (P < 0.05) in the intervention group. There were no significant changes in antioxidant capacity, DNA damage and markers of vascular health. Barriers to achieving recommended intakes of fruits and vegetables measured 12 months after the intervention period were amount, inconvenience and cost. CONCLUSION: While increasing fruit, juice and vegetable consumption increases circulating level of beneficial nutrients in healthy subjects, a 12-week intervention was not associated with effects on antioxidant status or lymphocyte DNA damage. TRIAL REGISTRATION: This trial was registered at Controlled-Trials.com; registration ISRCTN71368072.


Assuntos
Antioxidantes/metabolismo , Biomarcadores/sangue , Dieta , Frutas , Estado Nutricional , Verduras , Adulto , Atitude , Carotenoides , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vitaminas/sangue
12.
Mater Sci Eng C Mater Biol Appl ; 79: 516-524, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28629048

RESUMO

A high-strength regenerated bacterial cellulose (RBC)/bacterial cellulose (BC) microfilament of potential use as a biomaterial was successfully prepared via a wet spinning process. The BC not only consists of a 3-D network composed of nanofibers with a diameter of several hundred nanometers but also has a secondary structure consisting of highly oriented nanofibrils with a diameter ranging from a few nanometers to tens of nanometers which explains the reason for the high mechanical strength of BC. Furthermore, a strategy of partially dissolving BC was used and this greatly enhanced the mechanical performance of spun filament and a method called post-treatment was utilized to remove residual solvents from the RBC/BC filaments. A comparison of structure, properties, as well as cytocompatibility between BC nanofibers and RBC/BC microfilaments was achieved using morphology, mechanical properties, X-ray Diffraction (XRD) and an enzymatic hydrolysis assay. The RBC/BC microfilament has a uniform groove structure with a diameter of 50-60µm and XRD indicated that the crystal form was transformed from cellulose Iα to cellulose IIII and the degree of crystallinity of RBC/BC (33.22%) was much lower than the original BC (60.29%). The enzymatic hydrolysis assay proved that the RBC/BC material was more easily degraded than BC. ICP detection indicated that the residual amount of lithium was 0.07mg/g (w/w) and GC-MS analysis showed the residual amount of DMAc to be 8.51µg/g (w/w) demonstrating that the post-treatment process is necessary and effective for removal of residual materials from the RBC/BC microfilaments. Also, a cell viability assay demonstrated that after post-treatment the RBC/BC filaments had good cytocompatibility.


Assuntos
Celulose/química , Citoesqueleto de Actina , Materiais Biocompatíveis , Nanofibras , Difração de Raios X
13.
Mater Sci Eng C Mater Biol Appl ; 76: 845-855, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28482599

RESUMO

A new block polymer named poly 3-acrylamidophenylboronic acid-b-6-O-vinylazeloyl-d-galactose (p(AAPBA-b-OVZG)) was prepared using 3-acrylamidophenylboronic acid (AAPBA) and 6-O-vinylazeloyl-d-galactose (OVZG) via a two-step procedure involving S-1-dodecyl-S-(α', α'-dimethyl-α″-acetic acid) trithiocarbonate (DDATC) as chain transfer agent, 2,2-azobisisobutyronitrile (AIBN) as initiator and dimethyl formamide (DMF) as solvent. The structures of the polymer were examined by Fourier transform infrared spectroscopy (FT-IR) and 1H NMR and the thermal stability was determined by thermal gravimetric analysis (TG/DTG). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were utilized to evaluate the morphology and properties of the p(AAPBA-b-OVZG) nanoparticles. The cell toxicity, animal toxicity and therapeutic efficacy were also investigated. The results indicate the p(AAPBA-b-OVZG) was successfully synthesized and had excellent thermal stability. Moreover, the p(AAPBA-b-OVZG) nanoparticles were submicron in size and glucose-sensitive in phosphate-buffered saline (PBS). In addition, insulin as a model drug had a high encapsulation efficiency and loading capacity and the release of insulin was increased at higher glucose levels. Furthermore, the nanoparticles showed a low-toxicity in cell and animal studies and they were effective at decreasing blood glucose levels of mice over 96h. These p(AAPBA-b-OVZG) nanoparticles show promise for applications in diabetes treatment using insulin or other hypoglycemic proteins.


Assuntos
Nanopartículas , Animais , Ácidos Borônicos , Reagentes de Ligações Cruzadas , Portadores de Fármacos , Galactose , Insulina , Camundongos , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 173: 324-327, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27682217

RESUMO

The application of ultrasound to a solution can induce cavitional phenomena and generate high localised temperatures and pressures. These are dependent of the frequency used and have enabled ultrasound application in areas such as synthetic, green and food chemistry. High frequency (100kHz to 1MHz) in particular is promising in food chemistry as a means to inactivate enzymes, replacing the need to use periods of high temperature. A plant enzyme, horseradish peroxidase, was studied using time-resolved fluorescence techniques as a means to assess the effect of high frequency (378kHz and 583kHz) ultrasound treatment at equivalent acoustic powers. This uncovered the fluorescence emission from a newly formed species, attributed to the formation of di-tyrosine within the horseradish peroxidase structure caused by auto-oxidation, and linked to enzyme inactivation.


Assuntos
Peroxidase do Rábano Silvestre/química , Espectrometria de Fluorescência/métodos , Tirosina/química , Ultrassom/métodos , Ativação Enzimática , Peroxidase do Rábano Silvestre/metabolismo , Desnaturação Proteica , Solventes/química , Sonicação
15.
Mater Sci Eng C Mater Biol Appl ; 69: 1026-35, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27612799

RESUMO

Poly N-vinylcaprolactam-co-acrylamidophenylboronic acid p(NVCL-co-AAPBA) was prepared from N-vinylcaprolactam (NVCL) and 3-acrylamidophenylboronic acid (AAPBA), using 2,2-azobisisobutyronitrile (AIBN) as initiator. The synthesis and structure of the polymer were examined by Fourier Transform infrared spectroscopy (FT-IR) and (1)H-NMR. Dynamic light scattering (DLS), lower critical solution temperature (LCST) and transmission electron microscopy (TEM) were utilized to characterize the nanoparticles, CD spectroscopy was used to determine if there were any changes to the conformation of the insulin, and cell and animal toxicity were also investigated. The prepared nanoparticles were found to be monodisperse submicron particles and were glucose- and temperature-sensitive. In addition, the nanoparticles have good insulin-loading characteristics, do not affect the conformation of the insulin and show low-toxicity to cells and animals. These p(NVCL-co-AAPBA) nanoparticles may have some value for insulin or other hypoglycemic protein delivery.


Assuntos
Ácidos Borônicos/química , Caprolactama/análogos & derivados , Sistemas de Liberação de Medicamentos , Glucose/análise , Insulina/administração & dosagem , Insulina/farmacologia , Nanopartículas/química , Polímeros/química , Temperatura , Animais , Glicemia/metabolismo , Caprolactama/química , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Feminino , Humanos , Hidrodinâmica , Concentração de Íons de Hidrogênio , Masculino , Camundongos , Micelas , Peso Molecular , Nanopartículas/ultraestrutura , Tamanho da Partícula , Espectroscopia de Prótons por Ressonância Magnética , Ratos , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática
16.
Mater Sci Eng C Mater Biol Appl ; 62: 702-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26952475

RESUMO

Wet spun microfibers have great potential in the design of multifunctional controlled release materials. Curcumin (Cur) and vitamin E acetate (Vit. E Ac) were used as a model drug system to evaluate the potential application of the drug-loaded microfiber system for enhanced delivery. The drugs and polyacrylonitrile (PAN) were blended together and spun to produce the target drug-loaded microfiber using an improved wet-spinning method and then the microfibers were successfully woven into fabrics. Morphological, mechanical properties, thermal behavior, drug release performance characteristics, and cytocompatibility were determined. The drug-loaded microfiber had a lobed "kidney" shape with a height of 50-100 µm and width of 100-200 µm. The addition of Cur and Vit. E Ac had a great influence on the surface and cross section structure of the microfiber, leading to a rough surface having microvoids. X-ray diffraction and Fourier transform infrared spectroscopy indicated that the drugs were successfully encapsulated and dispersed evenly in the microfilament fiber. After drug loading, the mechanical performance of the microfilament changed, with the breaking strength improved slightly, but the tensile elongation increased significantly. Thermogravimetric results showed that the drug load had no apparent adverse effect on the thermal properties of the microfibers. However, drug release from the fiber, as determined through in-vitro experiments, is relatively low and this property is maintained over time. Furthermore, in-vitro cytocompatibility testing showed that no cytotoxicity on the L929 cells was found up to 5% and 10% respectively of the theoretical drug loading content (TDLC) of curcumin and vitamin E acetate. This study provides reference data to aid the development of multifunctional textiles and to explore their use in the biomedical material field.


Assuntos
Resinas Acrílicas/química , Portadores de Fármacos/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/toxicidade , Linhagem Celular , Curcumina/química , Curcumina/toxicidade , Liberação Controlada de Fármacos , Camundongos , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Vitamina E/química , Vitamina E/toxicidade , Difração de Raios X
17.
Carbohydr Polym ; 135: 72-8, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26453853

RESUMO

In order to enhance the efficiency and specificity of anticancer drug delivery and realize intelligently controlled release, a new drug carrier was developed. Graphene oxide (GO) was first modified with carboxymethyl chitosan (CMC), followed by conjugation of hyaluronic acid (HA) and fluorescein isothiocyanate (FI). The resulting GO-CMC-FI-HA conjugate was characterized and used as a carrier to encapsulate the anticancer drug doxorubicin (DOX) to study in vitro release behavior. The drug loading capacity is as high as 95% and the drug release rate under tumor cell microenvironment of pH 5.8 is significantly higher than that under physiological conditions of pH 7.4. Cell uptake studies show that the GO-CMC-FI-HA/DOX complex can specifically target cancer cells, which are over-expressing CD44 receptors and effectively inhibit their growth. The above results suggest that the functionalized graphene-based material has potential applications for targeted delivery and controlled release of anticancer drugs.


Assuntos
Quitosana/análogos & derivados , Portadores de Fármacos/química , Grafite/química , Ácido Hialurônico/química , Óxidos/química , Antineoplásicos/administração & dosagem , Antineoplásicos/química , Transporte Biológico , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Doxorrubicina/administração & dosagem , Doxorrubicina/química , Portadores de Fármacos/administração & dosagem , Liberação Controlada de Fármacos , Células HeLa , Humanos
18.
Colloids Surf B Biointerfaces ; 135: 209-216, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26255164

RESUMO

The thermoresponsive double-hydrophilic glycopolymer (DHG), Poly (6-O-vinyl-nonanedioyl-D-galactose-co-N-vinylcaprolactam) (P(OVNG-co-NVCL)) was synthesized via a chemo-enzymatic process and a free radical copolymerization and the resulting nanofibers were fabricated using an electrospinning process. The desired lower critical solution temperature (LCST) between 32 and 40 °C of the DHG polymers was achieved by adjusting the molar fraction of galactose monomer in the copolymers during the synthesis. The thermoresponsive DHG polymers were found to have good cytocompatibility with Hela cells as determined by the MTT assay, and special recognition of the protein peanut agglutinin (PNA). The drug release properties of these newly designed thermoresponsive DHG P(OVNG-co-NVCL) nanofibers are temperature regulated, can target specific proteins and have the potential application in the field of sustained drug release.


Assuntos
Preparações de Ação Retardada/química , Galactosídeos/química , Nanofibras/química , Polivinil/química , Caprolactama/química , Sobrevivência Celular/efeitos dos fármacos , Ácidos Cumáricos/administração & dosagem , Ácidos Cumáricos/química , Preparações de Ação Retardada/farmacocinética , Sistemas de Liberação de Medicamentos , Radicais Livres/química , Galactose/química , Galactosídeos/toxicidade , Células HeLa , Humanos , Lectinas , Nanofibras/toxicidade , Aglutinina de Amendoim/química , Polimerização , Polivinil/toxicidade , Temperatura
19.
Ultrason Sonochem ; 27: 509-514, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26186873

RESUMO

This study examined anthocyanin extraction using the application of ultrasound to raw freeze dried, microwaved and raw sliced Purple Majesty potato, a new pigmented potato variety rich in anthocyanins. A 20 kHz probe was used for the sonication at 3 different amplitudes (30%, 50% and 70%) and ethanol in water at different ratios (50:50 and 70:30 v/v) was used for the extraction. Anthocyanin extraction from raw freeze dried purple potato was optimal at an ethanol:water ratio (70:30; v/v) after 5 min of ultrasonication, while the least amount of anthocyanins was extracted from raw sliced potatoes. The application of microwaves (as a pre-treatment) before the UAE resulted in an increase in the amount of anthocyanins extracted and a decrease in the amount of solvent used. Analysis of variance showed that potato form, ultrasonication time, ultrasonication amplitude and solvent ratio as well as two and three way interactions between some of these factors had a very significant effect (p<0.000) on the amount of anthocyanins extracted.


Assuntos
Antocianinas/isolamento & purificação , Fracionamento Químico/métodos , Solanum tuberosum/química , Ondas Ultrassônicas , Criopreservação , Etanol/química , Micro-Ondas , Solventes/química , Fatores de Tempo , Água/química
20.
Br J Nutr ; 113(8): 1254-70, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25809236

RESUMO

High-protein diets are an effective means for weight loss (WL), but the mechanisms are unclear. One hypothesis relates to the release of gut hormones by either protein or amino acids (AA). The present study involved overweight and obese male volunteers (n 18, mean BMI 36·8 kg/m2) who consumed a maintenance diet for 7 d followed by fully randomised 10 d treatments with three iso-energetic WL diets, i.e. with either normal protein (NP, 15% of energy) or high protein (HP, 30%) or with a combination of protein and free AA, each 15% of energy (NPAA). Psychometric ratings of appetite were recorded hourly. On day 10, plasma samples were taken at 30 min intervals over two consecutive 5 h periods (covering post-breakfast and post-lunch) and analysed for AA, glucose and hormones (insulin, total glucose-dependent insulinotropic peptide, active ghrelin and total peptide YY (PYY)) plus leucine kinetics (first 5 h only). Composite hunger was 16% lower for the HP diet than for the NP diet (P<0·01) in the 5 h period after both meals. Plasma essential AA concentrations were greatest within 60 min of each meal for the NPAA diet, but remained elevated for 3-5 h after the HP diet. The three WL diets showed no difference for either fasting concentrations or the postprandial net incremental AUC (net AUCi) for insulin, ghrelin or PYY. No strong correlations were observed between composite hunger scores and net AUCi for either AA or gut peptides. Regulation of hunger may involve subtle interactions, and a range of signals may need to be integrated to produce the overall response.


Assuntos
Aminoácidos/química , Dieta Redutora , Proteínas Alimentares/química , Fome , Mucosa Intestinal/metabolismo , Adulto , Idoso , Apetite , Área Sob a Curva , Glicemia/análise , Composição Corporal , Índice de Massa Corporal , Peso Corporal , Polipeptídeo Inibidor Gástrico/sangue , Hormônios Gastrointestinais/sangue , Grelina/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/sangue , Obesidade/metabolismo , Peptídeo YY/sangue , Período Pós-Prandial , Psicometria , Triptofano/química , Redução de Peso , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...