Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Macromol Rapid Commun ; 44(21): e2300354, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37572076

RESUMO

Adopting only a small amount of azobenzene molecular to design liquid crystal photo-responsive materials capable of quick response and flexible adjustability is in high demand but is challenging. Herein, azobenzenemolecules into polyurethane elastomer containing crystalline structure for preparing azobenzene liquid-crystal elastomers (ALCEs) are demonstrated and this phenomenon of the synergistic effects between liquid crystal and crystalline phase is discovered. The key point of the work is that the synthetic ALCEs can utilize the reversible isomerism capability of azobenzene molecules under light irradiation, which can pry the motion of the macromolecular crystalline region in system to realize the large macroscopic deformation of the photo-responsive behavior. Obviously, the ALCEs sample containing azobenzene molecule and polyethylene glycol crystallization can quickly bend, illuminated by ultraviolet light and rapidly straighten under green light. Under the same ultraviolet irradiation, the bending speed, final bending angle, recovery rate and recovery ratio of ALCEs are larger than that of ALCEs without any crystalline structure. This ALCEs based on the synergistic effects between liquid crystal and crystalline phase can break through the current dilemma that the application of traditional azobenzene photo-responsive materials is limited by their concentration, greatly expanding the design thought and their scope of application.


Assuntos
Elastômeros , Cristais Líquidos , Elastômeros/química , Cristais Líquidos/química , Compostos Azo/química , Polietilenoglicóis
2.
Am J Kidney Dis ; 80(3): 364-372, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35288217

RESUMO

RATIONALE & OBJECTIVE: Phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN) with circulating serum autoantibodies to PLA2R (SAb+) but no deposits of PLA2R antigen in glomerular tissue by immunofluorescence (GAg-) has been reported. However, little is known about the clinicopathological characteristics or prognosis of this subtype of MN. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 130 SAb+ patients in China with biopsy-proven MN who had follow-up data and received immunosuppressive therapy. The median follow-up was 16 (IQR, 9-25) months. PREDICTOR: PLA2R antigen detection by immunofluorescence staining of kidney biopsy specimens. OUTCOMES: Complete remission (CR) was defined as proteinuria levels <0.3 g/d and a >50% decrease compared with a previously established baseline. Partial remission (PR) was defined as proteinuria levels <3.5 g/d and a >50% decrease compared with a previously established baseline. The kidney function outcome was defined as a >40% decrease in estimated glomerular filtration rate (eGFR) at the end of the study compared with baseline. ANALYTICAL APPROACH: Kaplan-Meier analysis of PR and CR comparing SAb+/GAg+ and SAb+/GAg- patients. Cox proportional hazards models to examine these associations were adjusted for confounders. RESULTS: Among 130 SAb+ patients with PLA2R-associated MN, 18 were GAg-. Compared with SAb+/GAg+ patients, those who were SAb+/GAg- presented with more severe kidney injury as evidenced by higher SAb titer, greater proteinuria, lower serum albumin concentrations, lower eGFR (all P < 0.05), and more severe disease with higher chronicity scores (P < 0.001) on kidney biopsies. SAb+/GAg- patients exhibited a significantly lower probability of PR (P < 0.001) and CR (P = 0.03) and were more likely to experience a >40% decrease in eGFR (P = 0.008) than patients who were SAb+/GAg+. After adjusting for clinical and pathologic variables available at the time of biopsy, compared with SAb+/GAg+ patients, SAb+/GAg- patients had a lower rate of experiencing remission (hazard ratio, 0.32 [95% CI, 0.15-0.68]; P = 0.003) and a higher rate of the >40% eGFR decrease outcome (hazard ratio, 7.66 [95% CI, 1.54-38.08]; P = 0.01). LIMITATIONS: Retrospective study, small sample size, and lack of a uniform approach to treatment. CONCLUSIONS: Seropositive PLA2R-associated MN without PLA2R staining on kidney biopsy may represent a distinct clinical subtype with more severe disease and a worse prognosis. GAg- is independently associated with poor response to treatment and >40% eGFR decrease in seropositive PLA2R-associated MN.


Assuntos
Glomerulonefrite Membranosa , Autoanticorpos , Biópsia , Humanos , Rim/patologia , Poliésteres/uso terapêutico , Proteinúria/etiologia , Receptores da Fosfolipase A2 , Estudos Retrospectivos , Coloração e Rotulagem
3.
Macromol Rapid Commun ; 43(3): e2100636, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34847277

RESUMO

High performance organic field effect transistor devices based on intrinsically scalable materials are of great significance in wearable electronics. In this work, an exclusive approach is reported to rationale the carrier mobility and stretchability of the conjugate polymers (CPs) by modifying the symmetry of the side chains species. Semiconductor CPs with symmetrical alkyl side chains (P(C-C)), symmetrical siloxane side chains (P(Si-Si)), and asymmetrical silicon-carbon side chains (P(C-Si)) are synthesized to investigate the influence of these side chains on the carrier mobility and mechanical behavior. The result shows that silicon-carbon asymmetric side chains can modulate the aggregation degree of polymer chains with a coherence length of 134 Å and maintain the mobility at 0.90 cm2 V-1 s-1 . P(C-Si) exhibits superior tensile properties that even elongation up to 100% the value of mobility retains a majority properties. The main reason is that the lowest coherence length of P(C-Si) polymer leads to an increased proportion of amorphous zones in its polymer film, which efficiently dissipates mechanical stresses. This study provides an efficient strategy for the design and synthesis of the CPs with high carrier transport properties-mechanical stability.


Assuntos
Polímeros , Siloxanas , Cetonas , Pirróis , Semicondutores
4.
Anal Chem ; 93(18): 7071-7078, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33905656

RESUMO

There is a great deal of interest in the development of nanoparticles for biomedicine. The question of how many nanoparticles are taken up by cells is important for biomedical applications. Here, we describe a fluorescence method for the quantitative measurement of the cellular uptake of polymer dots (Pdots) and a further estimation of intracellular Pdots photosensitizer for fluorescence imaging and photodynamic therapy. The approach relies on the high brightness, excellent stability, minimal aggregation quenching, and metalloporphyrin doping properties of the Pdots. We correlated the single-cell fluorescence brightness obtained from fluorescence spectrometry, confocal microscopy, and flow cytometry with the number of endocytosed Pdots, which was validated by inductively coupled plasma mass spectrometry. Our results indicated that, on average, ∼1.3 million Pdots were taken up by single cells that were incubated for 4 h with arginine 8-Pdots (40 µg/mL, ∼20 nm diameter). The absolute number of endocytosed Pdots of individual cells could be estimated from confocal microscopy by comparing the single-cell brightness with the average intensity. Furthermore, we investigated the cell viability as a result of an intracellular Pdots photosensitizer, from which the half maximal inhibitory concentration was determined to be ∼7.2 × 105 Pdots per cell under the light dose of 60 J/cm2. This study provides an effective method for quantifying endocytosed Pdots, which can be extended to investigate the cellular uptake of various conjugated polymer carriers in biomedicine.


Assuntos
Nanopartículas , Fotoquimioterapia , Pontos Quânticos , Fármacos Fotossensibilizantes , Polímeros , Semicondutores
5.
J Nanobiotechnology ; 18(1): 146, 2020 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-33076924

RESUMO

BACKGROUNDS: Surgical resection and adjunct chemotherapy or radio-therapy has been applied for the therapy of superficial malignant tumor in clinics. Whereas, there are still some problems limit its clinical use, such as severe pains and side effect. Thus, it is urgent need to develop effective, minimally invasive and low toxicity therapy stagey for superficial malignant tumor. Topical drug administration such as microneedle patches shows the advantages of reduced systemic toxicity and nimble application and, as a result, a great potential to treat superficial tumors. METHODS: In this study, microneedle (MN) patches were fabricated to deliver photosensitizer IR820 and chemotherapy agent cisplatin (CDDP) for synergistic chemo-photodynamic therapy against breast cancer. RESULTS: The MN could be completely inserted into the skin and the compounds carrying tips could be embedded within the target issue for locoregional cancer treatment. The photodynamic therapeutic effects can be precisely controlled and switched on and off on demand simply by adjusting laser. The used base material vinylpyrrolidone-vinyl acetate copolymer (PVPVA) is soluble in both ethanol and water, facilitating the load of both water-soluble and water-insoluble drugs. CONCLUSIONS: Thus, the developed MN patch offers an effective, user-friendly, controllable and low-toxicity option for patients requiring long-term and repeated cancer treatments.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Cisplatino/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Verde de Indocianina/farmacologia , Fotoquimioterapia/métodos , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Liberação Controlada de Fármacos , Tratamento Farmacológico , Feminino , Humanos , Verde de Indocianina/análogos & derivados , Camundongos Endogâmicos BALB C , Fármacos Fotossensibilizantes/administração & dosagem , Povidona/análogos & derivados
6.
Ann Vasc Surg ; 64: 389-396, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31669341

RESUMO

BACKGROUND: Hemodialysis access dysfunction is the major cause of hospitalization for patients undergoing hemodialysis due to stenosis at the anastomotic site. Our purpose is to perform a meta-analysis comparing target lesion primary patency rates at 6 months and one year, and major procedure-associated complications between drug-eluting balloon (DEB) and plain balloon angioplasty (PBA) for the treatment of arteriovenous fistula (AVF) or synthetic arteriovenous graft (AVG) stenosis. METHODS: PubMed, Embase, and MEDLINE databases were screened up to December 2018 to compare target lesion primary patency and complications between DEB and PBA. Two independent reviewers identified studies fulfilling our inclusion/exclusion criteria, extracted relevant data, and assessed quality. Fixed- or random-effects models were used to calculate overall effect estimates. RESULTS: Our literature search identified 10 articles eligible for inclusion in the review and analysis. DEB provided significantly higher target lesion primary patency rates for failing hemodialysis access than did PBA at 6 months [70% vs. 54%; odds ratio (OR), 2.71, 95% confidence interval (CI), 1.51 to 4.85; P < 0.01] and one year (59% vs. 37%; OR, 3.12, 95% CI, 2.14 to 4.55; P < 0.01). No major procedure-associated complications were observed in the 2 groups. CONCLUSIONS: DEB is an effective and safe technology that can significantly prolong 6-month and one-year target lesion primary patency for failing hemodialysis access when compared to PBA.


Assuntos
Angioplastia com Balão/instrumentação , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Implante de Prótese Vascular/efeitos adversos , Fármacos Cardiovasculares/administração & dosagem , Materiais Revestidos Biocompatíveis , Oclusão de Enxerto Vascular/terapia , Diálise Renal , Dispositivos de Acesso Vascular , Angioplastia com Balão/efeitos adversos , Fármacos Cardiovasculares/efeitos adversos , Desenho de Equipamento , Oclusão de Enxerto Vascular/etiologia , Oclusão de Enxerto Vascular/fisiopatologia , Humanos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Grau de Desobstrução Vascular
7.
Anal Chem ; 91(6): 4179-4185, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30786718

RESUMO

Photoblinking is a fundamental process that occurs exclusively in single fluorophores such as organic dyes, fluorescent proteins, and quantum dots. Here, we describe a strategy to achieve pronounced, high on/off ratio, and cooperative blinking in donor-acceptor multifluorophore systems. An ensemble of dye molecules doped in semiconducting polymer dots (Pdots) exhibit robust photoblinking, while the pristine Pdots and the dye in optically inert polymer matrices fluoresce continuously. Energy transfer from Pdots to dye acceptors produces photoblinking via a cooperative process, in which the bright state originates from the dye ensemble and the dark state is due to quenching of semiconducting polymer by hole polarons. Using the blinking Pdots in subcellular structures labeling, we demonstrated approximately 3.6-fold enhancement of imaging resolution in high-order super-resolution optical fluctuation nanoscopy as compared to conventional microscopy. Our findings not only demonstrate the exciting possibility of transforming a nonquantized ensemble into a single-emitter-like optical source but also provide an effective approach to generate superior photoblinking fluorescent probes for super-resolution imaging applications.


Assuntos
Transferência Ressonante de Energia de Fluorescência , Corantes Fluorescentes/química , Imagem Molecular/métodos , Polímeros/química , Pontos Quânticos , Fluorescência , Semicondutores
8.
Anal Chem ; 90(9): 5569-5575, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29569904

RESUMO

Semiconducting polymer dots (Pdots) as fluorescent probes have shown promising applications because of their excellent optical properties. However, apparent differences were observed in cytotoxicity assays, which might originate from impurities introduced in polymer synthesis or nanoparticle preparation. A simple gel-filtration-based purification method was used to address this issue. Purified Pdots displayed obviously decreased cytotoxicity as compared with the same batch of unpurified Pdots. The purified Pdots were further examined in a cytotoxicity study on mesenchymal stem cells (MSCs), which are very sensitive to exogenous probes. The results indicated that purified Pdots did not affect the proliferation ability of MSCs, while unpurified Pdots could have obvious cytotoxicity. In addition, the purified Pdots did not show cytotoxicity even after 6 months of storage. Our results demonstrated that gel filtration is an effective method for obtaining Pdots with minimal cytotoxicity, which are more suitable for biological applications.


Assuntos
Cromatografia em Gel , Células-Tronco Mesenquimais/citologia , Polímeros/química , Pontos Quânticos/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Camundongos , Imagem Óptica , Tamanho da Partícula , Polímeros/síntese química , Polímeros/farmacologia , Semicondutores , Relação Estrutura-Atividade , Propriedades de Superfície
9.
Anal Chem ; 90(24): 14629-14634, 2018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30463405

RESUMO

Singlet oxygen (1O2) plays important roles in many biological processes. However, it is very difficult to detect 1O2 in the intracellular environment because of its relatively low concentration and short lifetime. Here, we developed a ratiometric probe based on semiconducting polymer dots (Pdots) that can sensitively detect 1O2 in live cells. An organic dye, singlet oxygen sensor green (SOSG), was doped in polyfluorene Pdots, and excitation energy was efficiently transferred from the polymer to the SOSG dye. Accordingly, the Pdots showed constant blue fluorescence as a reference, and increased green fluorescence upon singlet oxygen generation. The ratiometric response of Pdots was examined in the intracellular environment by in situ 1O2 generation with a photosensitizer and light irradiation. Both spectroscopic measurements and confocal imaging were performed to monitor intracellular 1O2 generation during photodynamic therapy using the Pdot probe. Our results indicate that the SOSG-doped Pdots are promising for intracellular 1O2 detection.


Assuntos
Microscopia Confocal , Polímeros/química , Pontos Quânticos/química , Oxigênio Singlete/metabolismo , Corantes Fluorescentes/química , Células HeLa , Humanos , Oxigênio Singlete/análise , Espectrometria de Fluorescência
10.
J Environ Sci (China) ; 42: 227-235, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27090715

RESUMO

The colloidal properties of biogenic elemental sulfur (S(0)) cause solid-liquid separation problems, such as poor settling and membrane fouling. In this study, the separation of S(0) from bulk liquids was performed using flocculation. Polyaluminum chloride (PAC), polyacrylamide (PAM) and microbial flocculant (MBF) were compared to investigate their abilities to flocculate S(0) produced during the treatment of sulfate-containing wastewater. A novel approach with response surface methodology (RSM) was employed to evaluate the effects and interactions of flocculant dose, pH and stirring intensity, on the treatment efficiency in terms of the S(0) flocculation and the supernatant turbidity removal. The dose optimization results indicated that the S(0) flocculation efficiency decreased in the following order PAC>MBF>PAM. Optimum S(0) flocculation conditions were observed at pH4.73, a stirring speed of 129 r/min and a flocculant dose of 2.42 mg PAC/mgS. During optimum flocculation conditions, the S(0) flocculation rate reached 97.53%. Confirmation experiments demonstrated that employing PAC for S(0) flocculation is feasible and RSM is an efficient approach for optimizing the process of S(0) flocculation. The results provide basic parameters and conditions for recovering sulfur during the treatment of sulfate-laden wastewaters.


Assuntos
Enxofre/análise , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/análise , Resinas Acrílicas/química , Hidróxido de Alumínio/química , Floculação , Resíduos Industriais , Enxofre/química , Poluentes Químicos da Água/química
11.
Reprod Fertil Dev ; 26(3): 375-84, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23497913

RESUMO

The objective of this study was to evaluate the efficacy of a novel polydimethylsiloxane (PDMS) well-insert system for oocyte in vitro maturation (IVM) and in vitro embryo culture (IVC) in pigs. The PDMS well inserts, consisting of multiple microwells with connecting microchannels, resulted in equivalent blastocyst development compared with standard microdrop culture for IVC. These PDMS well inserts were then evaluated for IVM or IVC in a rocking versus static environment. The rocking environment during both oocyte IVM and embryo culture had detrimental effects on oocyte and embryo development compared with a static environment. Importantly, blastocyst development of oocytes and embryos cultured in the PDMS well inserts in the static environment was equivalent to that of standard microdrops. Further analysis of transcript abundance in blastocysts produced from these different environments revealed that the PDMS well-insert system may produce more viable embryos. In conclusion, this PDMS well-insert system can successfully mature oocytes and culture embryos in an individually-identifiable manner without compromising, and perhaps enhancing, developmental potential.


Assuntos
Dimetilpolisiloxanos , Técnicas de Cultura Embrionária/instrumentação , Embrião de Mamíferos/embriologia , Oócitos/crescimento & desenvolvimento , Técnicas de Reprodução Assistida/instrumentação , Sus scrofa , Técnicas de Cultura de Tecidos/instrumentação , Análise de Variância , Animais , Blastocisto/citologia , Primers do DNA/genética , Reação em Cadeia da Polimerase/métodos
12.
Eur J Pharm Biopharm ; 198: 114271, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38537907

RESUMO

Liposome is a promising carrier for pulmonary drug delivery and the nano-sized liposomes have been widely investigated in the treatment of lung diseases. However, there still lack the knowledge of micron-sized liposomes for lung delivery, which have more advantages in terms of drug loading and sustained drug release capacity. The micron-sized liposomes can be classified into multilamellar liposome (MLL) and multivesicular liposome (MVL) according to their microstructure, thus, this study focused on exploring how the micron-sized liposomes with different microstructure and phospholipid composition influence their interaction with the lung. The MLL and MVL were prepared from different types of phospholipids (including soya phosphatidylcholine (SPC), egg yolk phosphatidylcholine (EPC), and dipalmitoyl phosphatidylcholine (DPPC)) with geometric diameter around 5 µm, and their in vitro pulmonary cell uptake, in vivo lung retention and organ distribution were investigated. The results showed that the microstructure of liposomes didn't affect pulmonary cellular uptake, in vivo lung retention and organ distribution. MLL and MVL prepared with the same phospholipid had similar cellular uptake in both NR8383 cells and A549 cells, and both of them possessed prolonged lung retention and limited distribution in other organs during 72 h. Notably, the phospholipid type presented remarkable influence on liposomes' interaction with the lung. SPC-based liposomes exhibited higher cellular uptake than the DPPC-based ones in both NR8383 cells and A549 cells, also possessed a better lung retention behavior. In conclusion, this study might provide theoretical knowledge for designing micron-sized liposomes intended for lung delivery.


Assuntos
Lipossomos , Fosfolipídeos , Lipossomos/química , Fosfolipídeos/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Pulmão/metabolismo
13.
ACS Nano ; 18(11): 8325-8336, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38447099

RESUMO

Radiotherapy is a mainstay treatment used in clinics for locoregional therapy, although it still represents a great challenge to improve the sensitivity and accuracy of radiotherapy for tumors. Here, we report the conjugated polymer, polydiiododiacetylene (PIDA), with an iodine content of 84 wt %, as a highly effective computed tomography (CT) contrast agent and tumor microenvironment-responsive radiosensitizer. PIDA exhibited several key properties that contribute to the improvement of precision radiotherapy. The integrated PIDA nanofibers confined within the tumor envelope demonstrated amplified CT intensity and prolonged retention, providing an accurate calculation of dose distribution and precise radiation delivery for CT image-guided radiotherapy. Therefore, our strategy pioneers PIDA nanofibers as a bridge to cleverly connect a fiducial marker to guide accurate radiotherapy and a radiosensitizer to improve tumor sensitivity, thereby minimizing potential damage to surrounding tissues and facilitating on-demand therapeutic intervention in tumors.


Assuntos
Nanofibras , Neoplasias , Polímero Poliacetilênico , Radiossensibilizantes , Radioterapia Guiada por Imagem , Humanos , Carbono , Microambiente Tumoral , Radiossensibilizantes/farmacologia , Radiossensibilizantes/uso terapêutico
14.
J Control Release ; 366: 746-760, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38237688

RESUMO

Faced with the threat of lung cancer-related deaths worldwide, small interfering RNA (siRNA) can silence tumor related messenger RNA (mRNA) to tackle the issue of drug resistance with enhanced anti-tumor effects. However, how to increase lung tumor targeting and penetration with enhanced gene silencing are the issues to be addressed. Thus, the objective of this study is to explore the feasibility of designing non-viral siRNA vectors for enhanced lung tumor therapy via inhalation. Here, shell-core based polymer-lipid hybrid nanoparticles (HNPs) were prepared via microfluidics by coating PLGA on siRNA-loaded cationic liposomes (Lipoplexes). Transmission electron microscopy and energy dispersive spectroscopy study demonstrated that HNP consists of a PLGA shell and a lipid core. Atomic force microscopy study indicated that the rigidity of HNPs could be well tuned by changing thickness of the PLGA shell. The designed HNPs were muco-inert with increased stability in mucus and BALF, good safety, enhanced mucus penetration and cellular uptake. Crucially, HNP1 with the thinnest PLGA shell exhibited superior transfection efficiency (84.83%) in A549 cells, which was comparable to that of lipoplexes and Lipofectamine 2000, and its tumor permeability was 1.88 times that of lipoplexes in A549-3T3 tumor spheroids. After internalization of the HNPs, not only endosomal escape but also lysosomal exocytosis was observed. The transfection efficiency of HNP1 (39.33%) was 2.26 times that of lipoplexes in A549-3T3 tumor spheroids. Moreover, HNPs exhibited excellent stability during nebulization via soft mist inhaler. In conclusion, our study reveals the great potential of HNP1 in siRNA delivery for lung cancer therapy via inhalation.


Assuntos
Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/terapia , RNA Interferente Pequeno , Lipossomos , Transfecção , Células A549
15.
Langmuir ; 29(46): 14017-23, 2013 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-24147630

RESUMO

We developed a simple and general approach for constructing a wafer-scale monolayer, close-packed polystyrene (PS), and SiO2 sphere arrays, namely colloidal crystals, which have significant potential in various applications. The method combines slope self-assembly and thermal treatment to achieve large-area and high-quality colloidal crystal with a proper slant angle (θ) and latex concentration (volume fraction, φ). The dependence of the structures of colloidal crystals on a dispersion system was also investigated. Moreover, a theoretical analysis of the slope self-assembly method was proposed. In addition, we applied the method to assemble PS spheres on different kinds of substrates, which indicates that the method is a versatile and reliable way to fabricate monolayer colloidal crystals.


Assuntos
Temperatura , Água/química , Coloides , Poliestirenos/química , Dióxido de Silício/química
16.
Adv Healthc Mater ; 12(28): e2301292, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37458333

RESUMO

As a distinctly different way from apoptosis, ferroptosis can cause cell death through excessive accumulation of lipid peroxide (LPO) and show great potential for cancer therapy. However, efficient strategies for ferroptosis therapy are still facing great challenges, mainly due to insufficient endogenous H2 O2 or relatively high pH value for Fenton reaction-dependent ferroptosis, and the high redox level of tumor cells attenuates the oxidation therapy. Herein, an efficient lipid-based delivery system to load oxidation catalyst and glutathione peroxidase 4 (Gpx4) inhibitor is orchestrated, intending to amplify Fenton reaction-independent ferroptosis by bidirectional regulation of LPO accumulation. Ferric ammonium citrate (FAC), Gpx4 inhibitor sorafenib (SF), and unsaturated lipids are constructed into mPEG2K -DSPE-modified liposomes (Lip@SF&FAC). Influenced by the high level of intratumoral glutathione, FAC can be converted into Fe2+ , and subsequently the formed iron redox pair (Fe2+ /Fe3+ ) catalyzes unsaturated phospholipids of liposomes into LPO via a Fenton reaction-independent manner. Meanwhile, SF can downregulate LPO reduction by inhibiting Gpx4 activation. In vitro and in vivo antitumor experiments show that Lip@SF&FAC induces massive LPO accumulation in tumor cells and ultimately exhibits strong tumor-killing ability with negligible side effect. Consequently, this two-pronged approach provides a new ferroptosis strategy for predominant LPO accumulation and enhanced cancer therapy.


Assuntos
Ferroptose , Neoplasias , Humanos , Lipossomos/farmacologia , Oxirredução , Apoptose , Peróxidos Lipídicos , Sorafenibe/farmacologia , Sorafenibe/uso terapêutico , Neoplasias/tratamento farmacológico , Linhagem Celular Tumoral
17.
Eur J Pharm Biopharm ; 172: 101-111, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35149189

RESUMO

Liposome is the promising nanocarrier for pulmonary drug delivery and surface charge is its basic property. However, there is a lack of knowledge about relationship between the liposomal surface charge and its interaction with biological barriers in the lung. Therefore, the purpose of this research is to elucidate the influence of liposome surface charge on its in vivo fate. Firstly, liposomes with positive, negative and neutral surface charge were constructed and characterized, their compatibility towards pulmonary cells was studied. Then their interaction with different biological barriers in lung, including mucus, trachea, bronchoalveolar lavage fluid (BALF) and alveolar macrophage, were investigated. Their retention behavior in lung and systemic exposure were further explored. It was demonstrated that neutrally and negatively charged liposomes were safer than positively charged ones. In the conducting airway, liposome with positive surface charge could better enhance trachea distribution but only within 2 h. In the respiratory region, both neutrally and negatively charged liposomes presented improved mucus permeability, good stability in BALF containing pulmonary surfactant, decreased macrophage uptake, prolonged lung retention and decreased systemic exposure to other organs, with neutrally charged liposome showing superior performance than the negatively charged ones. While the positively charged liposome was not stable in lung microenvironment with aggregation observed, leading to increased alveolar macrophage uptake, thereby lower pulmonary retention and higher risk of systemic exposure. In conclusion, liposomal surface charge is a tunable formulation factor to modulate the interaction with biological barriers in the lung and thus in vivo fate of inhaled liposomes.


Assuntos
Lipossomos , Pulmão , Sistemas de Liberação de Medicamentos , Macrófagos , Macrófagos Alveolares
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120419, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34619506

RESUMO

Nitroaromatic compounds (NACs) can lead to various environmental pollution healh problems. In order to effectively recognize and sense NACs, a novel coordination polymers (CPs) with fluorescent characteristic [Zn3(btc)2(tpt)(H2O)2]·4H2O (1) (tpt = tris(4-pyridyl)triazine, H3btc = 1,3,5-benzenetricarboxylic acid) has been triumphantly prepared as an fluorescence probe by solvothermal method. 1 possesses remarkable PH stability ranging from 2.0 to 12.0 and is also stable in different pure organic solvents. It should be noted that 1 manifests a fluorescence quenching response against the detection of selectivity and sensitivity towards 2,4,6-trinitrophenol (TNP) in aqueous solution. It also makes analysis on the limit of detection towards TNP, which is as low as 0.94 µM compared with most reported CPs sensors for TNP. Therefore, 1 can become a satisfactory sensor for TNP detection with remarkable selectivity, strong anti-interference and favorable recyclability. In addition, the quenching mechanisms were also discussed. It was supposed that the mechanisms of photoinduced electron transfer (PET) as well as resonance energy transfer (RET) might be the main influencing factors.


Assuntos
Luminescência , Polímeros , Picratos , Zinco
19.
Biomater Sci ; 9(2): 328-346, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-32779646

RESUMO

Optical probes that specifically and sensitively change the optical properties upon contact with targets have become irreplaceable tools in fundamental biology and medicine. Semiconducting polymer dots (Pdots) have emerged as popular optical nanoplatforms because of their excellent characteristics, such as tunable luminescence, high brightness, superior stability and biocompatibility, for biological applications. In particular, facile surface and intra-particle modifications enable Pdots to detect various biological parameters, such as reactive oxygen species (ROS), typical metal ions, pH values, temperature and a variety of biomolecules. In this review, we provide a brief overview of the preparation and bio-functionalization strategies of Pdots. This review focuses on the applications of Pdots as optical probes in biosensors and describes the challenges in this field.


Assuntos
Técnicas Biossensoriais , Pontos Quânticos , Luminescência , Polímeros , Semicondutores
20.
J Comp Neurol ; 529(5): 1018-1028, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32720701

RESUMO

A prominent model of the origins of speech, known as the "frame/content" theory, posits that oscillatory lowering and raising of the jaw provided an evolutionary scaffold for the development of syllable structure in speech. Because such oscillations are nonvocal in most nonhuman primates, the evolution of speech required the addition of vocalization onto this scaffold in order to turn such jaw oscillations into vocalized syllables. In the present functional MRI study, we demonstrate overlapping somatotopic representations between the larynx and the jaw muscles in the human primary motor cortex. This proximity between the larynx and jaw in the brain might support the coupling between vocalization and jaw oscillations to generate syllable structure. This model suggests that humans inherited voluntary control of jaw oscillations from ancestral species, but added voluntary control of vocalization onto this via the evolution of a new brain area that came to be situated near the jaw region in the human motor cortex.


Assuntos
Mandíbula/fisiologia , Córtex Motor/fisiologia , Fonética , Fala/fisiologia , Adulto , Evolução Biológica , Mapeamento Encefálico , Tronco Encefálico/fisiologia , Feminino , Humanos , Laringe/fisiologia , Imageamento por Ressonância Magnética , Masculino , Músculos da Mastigação/fisiologia , Movimento , Volição , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA