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1.
Sensors (Basel) ; 21(9)2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34062895

RESUMO

Levofloxacin (LF) is a medically important antibiotic drug that is used to treat a variety of bacterial infections. In this study, three highly sensitive and selective carbon paste electrodes (CPEs) were fabricated for potentiometric determination of the LF drug: (i) CPEs filled with carbon paste (referred to as CPE); (ii) CPE coated (drop-casted) with ion-selective PVC membrane (referred to as C-CPE); (iii) CPE filled with carbon paste modified with a plasticizer (PVC/cyclohexanone) (referenced as P-CPE). The CPE was formulated from graphite (Gr, 44.0%) and reduced graphene oxide (rGO, 3.0%) as the carbon source, tricresyl phosphate (TCP, 47.0%) as the plasticizer; sodium tetrakis[3,5-bis(trifluoromethyl)phenyl] borate (St-TFPMB, 1.0%) as the ion exchanger; and levofloxacinium-tetraphenylborate (LF-TPB, 5.0%) as the lipophilic ion pair. It showed a sub-Nernstian slope of 49.3 mV decade-1 within the LF concentration range 1.0 × 10-2 M to 1.0 × 10-5 M, with a detection limit of 1.0 × 10-5 M. The PVC coated electrode (C-CPE) showed improved sensitivity (in terms of slope, equal to 50.2 mV decade-1) compared to CPEs. After the incorporation of PVC paste on the modified CPE (P-CPE), the sensitivity increased at 53.5 mV decade-1, indicating such improvement. The selectivity coefficient (log KLF2+,Fe+3pot.) against different interfering species (Na+, K+, NH4+, Ca2+, Al3+, Fe3+, Glycine, Glucose, Maltose, Lactose) were significantly improved by one to three orders of magnitudes in the case of C-CPE and P-CPE, compared to CPEs. The modification with the PVC membrane coating significantly improved the response time and solubility of the LF-TPB within the electrode matrix and increased the lifetime. The constructed sensors were successfully applied for LF determination in pharmaceutical preparation (Levoxin® 500 mg), spiked urine, and serum samples with high accuracy and precision.


Assuntos
Preparações Farmacêuticas , Cloreto de Polivinila , Carbono , Composição de Medicamentos , Eletrodos , Concentração de Íons de Hidrogênio , Levofloxacino , Potenciometria
2.
Int J Mol Sci ; 22(11)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34073734

RESUMO

Malignant glioma represents a fatal disease with a poor prognosis and development of resistance mechanisms against conventional therapeutic approaches. The distinct tumor zones of this heterogeneous neoplasm develop their own microenvironment, in which subpopulations of cancer cells communicate. Adaptation to hypoxia in the center of the expanding tumor mass leads to the glycolytic and angiogenic switch, accompanied by upregulation of different glycolytic enzymes, transporters, and other metabolites. These processes render the tumor microenvironment more acidic, remodel the extracellular matrix, and create energy gradients for the metabolic communication between different cancer cells in distinct tumor zones. Escape mechanisms from hypoxia-induced cell death and energy deprivation are the result. The functional consequences are more aggressive and malignant behavior with enhanced proliferation and survival, migration and invasiveness, and the induction of angiogenesis. In this review, we go from the biochemical principles of aerobic and anaerobic glycolysis over the glycolytic switch, regulated by the key transcription factor hypoxia-inducible factor (HIF)-1α, to other important metabolic players like the monocarboxylate transporters (MCTs)1 and 4. We discuss the metabolic symbiosis model via lactate shuttling in the acidic tumor microenvironment and highlight the functional consequences of the glycolytic switch on glioma malignancy. Furthermore, we illustrate regulation by micro ribonucleic acids (miRNAs) and the connection between isocitrate dehydrogenase (IDH) mutation status and glycolytic metabolism. Finally, we give an outlook about the diagnostic and therapeutic implications of the glycolytic switch and the relation to tumor immunity in malignant glioma.


Assuntos
Neoplasias Encefálicas/metabolismo , Encéfalo/metabolismo , Glioma/metabolismo , Glicólise , Ácido Láctico/metabolismo , Microambiente Tumoral , Animais , Química Encefálica , Neoplasias Encefálicas/fisiopatologia , Anidrases Carbônicas , Glioma/fisiopatologia , Humanos , Concentração de Íons de Hidrogênio , Neovascularização Patológica
3.
Nat Commun ; 12(1): 3393, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099712

RESUMO

The iron gall ink-triggered chemical corrosion of hand-written documents is a big threat to Western cultural heritages, which was demonstrated to result from the iron gall (GA-Fe) chelate-promoted reactive oxygen species generation. Such a phenomenon has inspired us to apply the pro-oxidative mechanism of GA-Fe to anticancer therapy. In this work, we construct a composite cancer nanomedicine by loading gallate into a Fe-engineered mesoporous silica nanocarrier, which can degrade in acidic tumor to release the doped Fe3+ and the loaded gallate, forming GA-Fe nanocomplex in situ. The nanocomplex with a highly reductive ligand field can promote oxygen reduction reactions generating hydrogen peroxide. Moreover, the resultant two-electron oxidation form of GA-Fe is an excellent Fenton-like agent that can catalyze hydrogen peroxide decomposition into hydroxyl radical, finally triggering severe oxidative damage to tumors. Such a therapeutic approach by intratumoral synthesis of GA-Fe nano-metalchelate may be instructive to future anticancer researches.


Assuntos
Antineoplásicos/administração & dosagem , Ácido Gálico/administração & dosagem , Ferro/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Catálise , Complexos de Coordenação/administração & dosagem , Complexos de Coordenação/química , Complexos de Coordenação/metabolismo , Portadores de Fármacos/química , Feminino , Ácido Gálico/química , Ácido Gálico/metabolismo , Células HeLa , Células Endoteliais da Veia Umbilical Humana , Humanos , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Radical Hidroxila/química , Radical Hidroxila/metabolismo , Injeções Intravenosas , Ferro/química , Ferro/metabolismo , Ligantes , Nanopartículas Metálicas/química , Camundongos , Neoplasias/patologia , Oxirredução , Oxigênio/metabolismo , Dióxido de Silício/química , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Braz J Biol ; 82: e234413, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34105658

RESUMO

The viscera and other residues from fish processing are commonly discarded by the fishing industry. These by-products can be a source of digestive enzymes with industrial and biotechnological potential. In this study, we aimed at the extraction, characterization, and application of acidic proteases from the stomach of Carangoides bartholomaei (Cuvier, 1833). A crude extract from the stomachs was obtained and submitted to a partial purification process by salting-out, which obtained a Purified Extract (PE) with a specific proteolytic activity of 54.0 U⋅mg-1. A purification of 1.9 fold and a yield of 41% were obtained. The PE presents two isoforms of acidic proteases and a maximum proteolytic activity at 45 °C and pH 2.0. The PE acidic proteolytic activity was stable in the pH range of 1.5 to 7.0 and temperature from 25 °C to 50 °C. Purified Extract kept 35% of its proteolytic activity at the presence of NaCl 15% (m/v) but was totally inhibited by pepstatin A. Purified Extract aspartic proteases presented high activity in the presence of heavy metals such as Cd2+, Hg2+, Pb2+, Al3+, and Cu2+. The utilization of PE as an enzymatic addictive in the collagen extraction from Nile tilapia scales has doubled the process yield. The results indicate the potential of these aspartic proteases for industrial and biotechnological applications.


Assuntos
Peptídeo Hidrolases , Estômago , Concentração de Íons de Hidrogênio , Temperatura
5.
Braz J Biol ; 82: e239449, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34105678

RESUMO

Alpha amylase, catalyzing the hydrolysis of starch is a ubiquitous enzyme with tremendous industrial applications. A 1698 bp gene coding for 565 amino acid amylase was PCR amplified from Geobacillus thermodenitrificans DSM-465, cloned in pET21a (+) plasmid, expressed in BL21 (DE3) strain of E. coli and characterized. The recombinant enzyme exhibited molecular weight of 63 kDa, optimum pH 8, optimum temperature 70°C, and KM value of 157.7µM. On pilot scale, the purified enzyme efficiently removed up to 95% starch from the cotton fabric indicating its desizing ability at high temperature. 3D model of enzyme built by Raptor-X and validated by Ramachandran plot appeared as a monomer having 31% α-helices, 15% ß-sheets, and 52% loops. Docking studies have shown the best binding affinity of enzyme with amylopectin (∆G -10.59). According to our results, Asp 232, Glu274, Arg448, Glu385, Asp34, Asn276, and Arg175 constitute the potential active site of enzyme.


Assuntos
Escherichia coli , alfa-Amilases , Clonagem Molecular , Estabilidade Enzimática , Escherichia coli/genética , Geobacillus , Concentração de Íons de Hidrogênio , Temperatura , alfa-Amilases/genética , alfa-Amilases/metabolismo
6.
J Enzyme Inhib Med Chem ; 36(1): 1230-1235, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34074197

RESUMO

The ongoing Covid-19 is a contagious disease, and it is characterised by different symptoms such as fever, cough, and shortness of breath. Rising concerns about Covid-19 have severely affected the healthcare system in all countries as the Covid-19 outbreak has developed at a rapid rate all around the globe. Intriguing, a clinically used drug, acetazolamide (a specific inhibitor of carbonic anhydrase, CA, EC 4.2.1.1), is used to treat high-altitude pulmonary oedema (HAPE), showing a high degree of clinical similarities with the pulmonary disease caused by Covid-19. In this context, this preliminary study aims to provide insights into some factors affecting the Covid-19 patients, such as hypoxaemia, hypoxia as well as the blood CA activity. We hypothesise that patients with Covid-19 problems could show a dysregulated acid-base status influenced by CA activity. These preliminary results suggest that the use of CA inhibitors as a pharmacological treatment for Covid-19 may be beneficial.


Assuntos
Acetazolamida/uso terapêutico , Antivirais/uso terapêutico , COVID-19/tratamento farmacológico , Inibidores da Anidrase Carbônica/uso terapêutico , Anidrases Carbônicas/sangue , Equilíbrio Ácido-Base/efeitos dos fármacos , Doença da Altitude/sangue , Doença da Altitude/tratamento farmacológico , Anticonvulsivantes/uso terapêutico , Bicarbonatos/sangue , COVID-19/sangue , COVID-19/diagnóstico por imagem , COVID-19/virologia , Dióxido de Carbono/sangue , Tosse/sangue , Tosse/tratamento farmacológico , Tosse/patologia , Tosse/virologia , Reposicionamento de Medicamentos , Dispneia/sangue , Dispneia/tratamento farmacológico , Dispneia/patologia , Dispneia/virologia , Febre/sangue , Febre/tratamento farmacológico , Febre/patologia , Febre/virologia , Humanos , Concentração de Íons de Hidrogênio , Hipertensão Pulmonar/sangue , Hipertensão Pulmonar/tratamento farmacológico , Hipóxia/sangue , Hipóxia/tratamento farmacológico , Hipóxia/patologia , Hipóxia/virologia , Oximetria , Projetos de Pesquisa , SARS-CoV-2/patogenicidade , SARS-CoV-2/fisiologia , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X
7.
J Hazard Mater ; 415: 125653, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34088177

RESUMO

This research experiment was conducted to investigate the potential of Brevundimonas species IITISM22 to remove mercury by using live biomass of bacterial cells at 298, 308, and 318 K. Characterization of bio-sorbent was done by FT-IR and SEM-EDX. The prime functional groups accountable for binding Hg were OH, -NH2, -CH, -SH and -COO. The deformed bacterial structure was seen after Hg adsorption over the bacterial cell. Influences of different experimental factors, such as pH, temperature, contact time, Hg concentration, and biomass dose was examined. IITISM22 exhibited the highest Hg absorption at pH 6.5, contact time of 4 h, and showed an increased adsorption capacity while increasing the concentration of Hg. Kinetics were recommended by pseudo-second-order for adsorption process and isotherm was adequately defined by the Linear Langmuir isotherm model (KL) = 1.4, 1.2, 0.9 mg/l; (RL) = 0.020, 0.015, 0.013, respectively than Freundlich isotherm model. The Activation energy (Ea) of biosorption calculated were (131.10 KJ/mole) by using Arrhenius equation, and the thermodynamic parameters were ΔG⸰ (-41.03, -16.33, -16.12 KJ/mol), ΔH⸰ (-36.87 KJ/mol) and ΔS⸰ (-194.03 J/mol), respectively. These findings suggest that the removal process was based on chemisorption and the biosorption was exothermic. The result of the current experiment indicated that the IITISM22 could be an authentic biosorbent for Hg detoxification.


Assuntos
Mercúrio , Poluentes Químicos da Água , Adsorção , Biomassa , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
8.
J Hazard Mater ; 415: 125749, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34088204

RESUMO

Biochar prepared from sludge and liriodendron leaves (SLAC) was modified by Fe3+ (SLAC-Fe), and they were used to remove methyl orange (MO) from single system and aqueous solution with Cr6+. The physical and chemical properties of biochar were characterized by BET, SEM, TEM, EDS, FTIR and XPS. The influences of initial MO concentration, adsorbent dose, pH, contact time and temperature on the adsorption of MO by biochar were investigated. The results indicated that SLAC-Fe had a higher removal efficiency for MO than SLAC. In the binary system, the maximum adsorption capacities of MO were 0.26 and 0.22 mmol/g with Cr6+ concentrations of 0.2 and 0.8 mmol/L, respectively. The adsorption kinetic model of pseudo-second-order fitted well with the experimental data of MO in single system. The equilibrium experimental data of MO in single and binary component systems were fitted well to Freundlich isotherm models. It was based on chemical and multilayer adsorption. It could be concluded that there was a competitive adsorption between Cr6+ and MO. The reason was that the HCrO4- and Cr2O72- competed with SO3- for the effective adsorption sites on the surface of SLAC-Fe, resulting in a reduction in the adsorption capacity of MO.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Adsorção , Compostos Azo , Carvão Vegetal , Concentração de Íons de Hidrogênio , Ferro , Cinética , Poluentes Químicos da Água/análise
9.
Sensors (Basel) ; 21(10)2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34069524

RESUMO

Surfactant liquid-membrane type sensors are usually made of a PVC, ionophore and a plasticizer. Plasticizers soften the PVC. Due to their lipophilicity, they influence the ion exchange across the membrane, ionophore solubility, membrane resistance and, consequently, the analytical signal. We used the DMI-TPB as an ionophore, six different plasticizers [2-nitrophenyl-octyl-ether (P1), bis(2-ethylhexyl) phthalate (P2), bis(2-ethylhexyl) sebacate (P3), 2-nitrophenyl phenyl ether (P4), dibutyl phthalate (P5) and dibutyl sebacate (P6)] and a PVC to produce ionic surfactant sensors. Sensor formulation with P1 showed the best potentiometric response to four usually used cationic surfactant, with the lowest LOD, 7 × 10-7 M; and potentiometric titration curves with well-defined and sharp inflexion points. The sensor with P6 showed the lowest analytical performances. Surfactant sensor with P1 was selected for quantification of cationic surfactant in model solutions and commercial samples of disinfectants and antiseptics. It showed high accuracy and precision in all determinations, with recovery from 98.2 to 99.6, and good agreement with the results obtained with surfactant sensor used as a referent one, and a standard two-phase titration method. RDS values were lower than 0.5% for all determinations.


Assuntos
Anti-Infecciosos Locais , Desinfetantes , Concentração de Íons de Hidrogênio , Plastificantes , Cloreto de Polivinila , Potenciometria , Tensoativos
10.
Talanta ; 232: 122475, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34074443

RESUMO

The weakly alkaline microenvironment (pH ~8.0) in mitochondria plays a vital role in maintaining its morphology and function. Thus monitoring mitochondrial pH (pHmito) is of great significance. Herein, a ratiometric fluorescent probe (ENBT) for pHmito imaging in mitochondria of living cells is reported. pH variation closely correlates to intramolecular charge transfer (ICT) from naphthol to ß-naphthothiazolium. ENBT exhibits a remarkable decrease on ratiometric fluorescence at λem1/λem2 = F595/F700 in response to pH variation within 6.30-9.29. In addition, ENBT has an ideal pKa value of 7.94 ± 0.08, which is advantageous in accurate sensing of pHmito. Moreover, ENBT has a Stokes shift of >150 nm, which effectively eliminates the potential interference from the excitation irradiation. ENBT shows excellent capability for specific staining of mitochondria with low cytotoxicity, which is most suitable for pHmito imaging in live cells. The probe was applied for monitoring pHmito variation in mitochondria of live cells caused by H2O2, NAC (N-Acetyl-l-cysteine), NH4Cl, carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and lactate/pyruvate. The morphological alterations of mitochondria in living cells after treatment by CCCP were further evaluated.


Assuntos
Corantes Fluorescentes , Peróxido de Hidrogênio , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Mitocôndrias , Imagem Óptica
11.
Braz J Biol ; 82: e244735, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34076169

RESUMO

L-Asparaginase catalysing the breakdown of L-Asparagine to L-Aspartate and ammonia is an enzyme of therapeutic importance in the treatment of cancer, especially the lymphomas and leukaemia. The present study describes the recombinant production, properties and anticancer potential of enzyme from a hyperthermophilic archaeon Pyrococcus abyssi. There are two genes coding for asparaginase in the genome of this organism. A 918 bp gene encoding 305 amino acids was PCR amplified and cloned in BL21 (DE3) strain of E. coli using pET28a (+) plasmid. The production of recombinant enzyme was induced under 0.5mM IPTG, purified by selective heat denaturation and ion exchange chromatography. Purified enzyme was analyzed for kinetics, in silico structure and anticancer properties. The recombinant enzyme has shown a molecular weight of 33 kDa, specific activity of 1175 U/mg, KM value 2.05mM, optimum temperature and pH 80°C and 8 respectively. No detectable enzyme activity found when L-Glutamine was used as the substrate. In silico studies have shown that the enzyme exists as a homodimer having Arg11, Ala87, Thr110, His112, Gln142, Leu172, and Lys232 being the putative active site residues. The free energy change calculated by molecular docking studies of enzyme and substrate was found as ∆G - 4.5 kJ/mole indicating the affinity of enzyme with the substrate. IC50 values of 5U/mL to 7.5U/mL were determined for FB, caco2 cells and HepG2 cells. A calculated amount of enzyme (5U/mL) exhibited 78% to 55% growth inhibition of caco2 and HepG2 cells. In conclusion, the recombinant enzyme produced and characterized in the present study offers a good candidate for the treatment of cancer. The procedures adopted in the present study can be prolonged for in vivo studies.


Assuntos
Antineoplásicos/farmacologia , Asparaginase , Pyrococcus abyssi , Asparaginase/biossíntese , Asparaginase/farmacologia , Células CACO-2 , Estabilidade Enzimática , Escherichia coli/genética , Humanos , Concentração de Íons de Hidrogênio , Simulação de Acoplamento Molecular , Pyrococcus abyssi/enzimologia , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/farmacologia , Especificidade por Substrato
12.
Chemosphere ; 276: 130191, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34088088

RESUMO

In this study, Levenberg Marquardt back propagation algorithm was used to train the Artificial Neural Network (ANN) and to predict the adsorptive removal of cationic dye Basic Violet 03 (BV03) by biochar derived from biowaste of groundnut hull. The experimental conditions such as solution pH, biochar dose, initial dye concentration, contact time and temperature were used as input variables and BV03 percentage removal as target. The hidden and the output layer of the network was trained by tangent sigmoid and liner transfer functions. The feasibility of the adsorption process is evaluated by the kinetic studies and it exhibited that pseudo-second order kinetic models fit well with experimental data. The adsorbent stability and adsorption mechanism has been discoursed by the thermodynamic characteristics and sorption free energy. The predicted target values were compared with the experiment resulted in a better correlation coefficient of 0.9920. Thus, the results attained from this ANN model was found to be effective in predicting the percentage removal of BV03 dye at any given operating condition.


Assuntos
Redes Neurais de Computação , Carvão Vegetal , Concentração de Íons de Hidrogênio , Cinética , Termodinâmica
13.
Water Sci Technol ; 83(11): 2700-2713, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34115624

RESUMO

Bioconversion (e.g. anaerobic fermentation and compost) is the common recycling method of waste activated sludge (WAS) and its hydrolysis, as the rate-limiting step of fermentation, could be accelerated by protease. However, the commercial protease was unstable in a sludge environment, which increased the cost. An endogenous alkaline protease stable in sludge environment was screened in this study and its suitability for treating the sludge was analyzed. The optimal production medium was determined by Response Surface Methodology as starch 20 g/L, KH2PO4 4 g/L, MgSO4·7H2O 1 g/L, sodium carboxy-methyl-cellulose 4 g/L, casein 4 g/L and initial pH 11.3, which elevated the yield of protease by up to 15 times (713.46 U/mL) compared with the basal medium. The obtained protease was active and stable at 35 °C-50 °C and pH 7.0-11.0. Furthermore, it was highly tolerant to sludge environment and maintained high efficiency of sludge hydrolysis for a long time. Thus, the obtained protease significantly hydrolyzed WAS and improved its bioavailability. Overall, this work provided a new insight for enzymatic treatment of WAS by isolating the endogenous and stable protease in a sludge environment, which would promote the resource utilization of WAS by further bioconversion.


Assuntos
Ácidos Graxos Voláteis , Esgotos , Proteínas de Bactérias , Endopeptidases , Fermentação , Concentração de Íons de Hidrogênio , Hidrólise
14.
Water Sci Technol ; 83(11): 2714-2723, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34115625

RESUMO

The textile industry is one of the main generators of industrial effluent due to the large volumes of water containing a wide variety of pollutants, including dyes. Thus, the present study aimed to remove the Disperse Blue 56 dye present in synthetic textile effluent using ionic flocculation through surfactant flocs produced from animal/vegetable fat, assessing the system at different surfactant concentrations and temperatures. The process kinetics, adsorption mechanism and equilibrium were evaluated. The results show that the kinetics was better described by the Elovich model when compared to pseudo-first order and pseudo-second order models, indicating that chemical adsorption occurs during the process. The study of the adsorption mechanism obtained lower outer layer diffusivities than their intra-particle counterparts, demonstrating that the dye transport to the surfactant floc is controlled through the outer layer. The Langmuir isotherm was suitable for equilibrium data and the separation factor calculated showed that the isotherm is classified as favorable. Dye removal efficiency reached 87% after 360 minutes of contact between the effluent and the surfactant flocs, indicating that ionic flocculation is an efficient alternative in the treatment of textile effluent containing disperse dye.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Adsorção , Antraquinonas , Corantes , Floculação , Concentração de Íons de Hidrogênio , Cinética , Indústria Têxtil , Têxteis , Poluentes Químicos da Água/análise
15.
Water Sci Technol ; 83(11): 2793-2808, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34115632

RESUMO

In this work, mixed oxides of LaxCa1-xMnO3 perovskite type (x = 0, 0.5 and 1.0) were synthesized through modified proteic method using collagen and calcination process at 700 °C/2 h in order to remove the commercial textile dye Bezaktiv Blue S-MAX from water. Oxides were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 physisorption, scanning electron microscopy (SEM) and point of zero charge (PZC) techniques while the dye only by the first two techniques. The XRD showed that perovskite monophase was obtained for x = 0.5 and 1.0. However, for x = 0, the low crystalline perovskite phase was obtained in the midst of precursor oxides. FTIR showed the adsorption process did not damage the adsorbents structure. The successful obtained materials have meso and macroporous with slit or cavity shape, rough surface and particles with varying sizes. The pseudo-second-order model was the one that best fit the kinetic data. The process must occur through electrostatic surface interactions between the adsorbent surface and the dye molecule. For the equilibrium study, Langmuir isotherm is the most suitable when using LaMnO3 adsorbent, while Freundlich isotherm was better suited when used the other two materials. The adsorbents were termally regenerated and reused five times. The best performance was exhibited by LaMnO3.


Assuntos
Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Água , Poluentes Químicos da Água/análise
16.
Int J Nanomedicine ; 16: 3185-3199, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34007173

RESUMO

Background: The acidic microenvironment of cancer can promote tumor metastasis and drug resistance. Acidic tumor microenvironment-targeted therapy is currently an important means for treating tumors, inhibiting metastasis, and overcoming drug resistance. In this study, a dual pH-responsive DOX-encapsulated liposome (DOPE-DVar7-lip@DOX) was designed and fabricated for targeting the acidic tumor microenvironment. On the one hand, the response of acid-sensitive peptide (DVar7) to the acidic tumor microenvironment increased the uptake of liposomes in tumors and prolonged the retention time; on the other hand, the response of acid-sensitive phospholipid (DOPE) to the acidic tumor microenvironment improved the controlled release of DOX in tumors. Methods: The acid-sensitive peptide DVar7 modified liposomes can be obtained by simple incubation of DSPE-DVar7 with DOX-loaded DOPE liposomes (DOPE-lip@DOX). The tumor targeting of the dual pH-responsive liposome was investigated in vitro and in vivo by near-infrared fluorescence imaging. The tumor therapeutic efficacy of DOPE-DVar7-lip@DOX was evaluated in breast cancer mouse model using the traditional liposome as a control. Moreover, we regulated the tumor microenvironment acidity by injecting glucose to further enhance the therapeutic efficacy of cancer. Results: DVar7 can allosterically insert into the tumor cell membrane in the acidic tumor microenvironment to enhance the tumor uptake of liposomes and prolong the retention time of liposomes in tumor. In addition, the therapeutic efficacy of pH-responsive liposomes can be further enhanced by glucose injection regulating the acidity of tumor microenvironment. Discussion: DVar7 modified acid-sensitive nanocarriers combined with acidity regulation have great potential to improve drug resistance in clinical practice, thus improving the response rate and therapeutic effect of chemotherapy.


Assuntos
Doxorrubicina/uso terapêutico , Sistemas de Liberação de Medicamentos , Glucose/administração & dosagem , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Liberação Controlada de Fármacos , Endocitose/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Lipossomos , Camundongos Endogâmicos BALB C , Neoplasias/patologia , Imagem Óptica , Tamanho da Partícula , Fosfatidiletanolaminas/química
17.
Int J Nanomedicine ; 16: 3217-3240, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34007175

RESUMO

Background: GD2 is a mainstream biomarker for neuroblastoma (NB)-targeted therapy. Current anti-GD2 therapeutics exhibit several side effects since GD2 is also expressed at low levels on normal cells. Thus, current anti-GD2 therapeutics can be compromised by the coexistence of the target receptor on both cancer cells and normal cells. Propose: Aptamers are promising and invaluable molecular tools. Because of the pH difference between tumor and normal cells, in this study, we constructed a pH-sensitive aptamer-mediated drug delivery system (IGD-Targeted). Methods: In vivo Systematic Evolution of Ligands by Exponential Enrichment (SELEX) was used to generate a novel GD2 aptamer. Flow cytometry and molecular docking were applied to assess the binding specificities, affinities abilities of the aptamers. Confocal microscope, CCK8 assay, and BrdU assay were utilized to evaluate whether IGD-Targeted could only bind with GD2 at acidic environment. To evaluate whether IGD-Targeted could inhibit GD2-positive tumor and protect normal cells, in vivo living imaging, histomorphological staining, blood test, and RNA-sequencing were observed in animal model. Results: GD2 aptamer termed as DB67 could bind with GD2-positive cells with high specificity, while has minimal cross-reactivities to other negative cells. It has been validated that the i-motif in IGD-Targeted facilitates the binding specificity and affinity of the GD2 aptamer to GD2-positive NB tumor cells but does not interfere with GD2-positive normal cells at the pH of the cellular microenvironment. In addition, IGD-Targeted is capable of delivering Dox to only GD2-positive NB tumor cells and not to normal cells in vivo and in vitro, resulting in precise inhibition of tumor cells and protection of normal cells. Conclusion: This study suggests that IGD-Targeted as a promising platform for NB therapy which could show greater tumor inhibition and fewer side effects to normal cells, regardless of the existence of the same receptor on the target and nontarget cells.


Assuntos
Antineoplásicos/uso terapêutico , Aptâmeros de Nucleotídeos/química , DNA/química , Nanomedicina , Neuroblastoma/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Sistemas de Liberação de Medicamentos , Feminino , Humanos , Concentração de Íons de Hidrogênio , Camundongos Endogâmicos BALB C , Simulação de Acoplamento Molecular , Neuroblastoma/genética , Neuroblastoma/patologia , Técnica de Seleção de Aptâmeros , Transcriptoma/genética , Microambiente Tumoral/efeitos dos fármacos
18.
J Hazard Mater ; 414: 125567, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34030414

RESUMO

The presence of ciprofloxacin (CIP) in natural water may cause potential threats to the environment. Adsorption is a convenient and efficient method to remove CIP from aqueous solution. Bayberry tannin (BT), a natural polyphenol, has been utilized in the synthesis of tannin foam (TF) due to its abundant polyphenolic hydroxyls to chelate with metal ions. The obtained TF was subsequently immobilized with Fe3+ via a facile chelative adsorption to fabricate functional tannin foam (TF-Fe), which was highly porous, with a porosity of 78.93%. The Fe species in the TF-Fe featured good dispersity, which were active for chelative adsorption of CIP. The adsorption of CIP on the TF-Fe was a pH-dependent process. At the optimized pH of 7.0, the TF-Fe provided the adsorption capacity of 91.8 mg g-1. When applied in removal of CIP at the low concentration of 2.0 µg mL-1, a high removal efficiency of 96.60% was still obtained, which was superior to commercial activated carbon (28.78%). The adsorption kinetics were well fitted by the pseudo-second-order rate model while the adsorption isotherms were well described by the Langmuir model. The TF-Fe was capable of recycling, which still maintained a high removal efficiency of 92.25% in the 5th cycle.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Adsorção , Ciprofloxacina , Concentração de Íons de Hidrogênio , Cinética , Taninos , Poluentes Químicos da Água/análise
19.
Nanoscale ; 13(20): 9402-9414, 2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34002757

RESUMO

The dense extracellular matrix (ECM) in tumor tissue severely hinders the penetration and enrichment of antitumor nanomedicines, which could significantly affect their efficiency. In this study, we used pH-sensitive nanocarriers loaded with collagenase (Col) to remold the tumor microenvironment (TME). Furthermore, we combined the collagenase delivery system with a nanomedicine to improve its penetration and enrichment in the tumor, thereby improving efficacy. We synthesized acetalated dextran (Ace-DEX) with an ideal pH-sensitivity as the carrier material of collagenase. Under mild preparation conditions, collagenase was loaded into Ace-DEX nanoparticles (NPs) with a high loading capacity (>4%) and remained highly active (>90%). Col-carrying NPs (Col-NPs) significantly reduced the tumor collagen content by 15.1%. Pretreatment with Col-NPs increased the accumulation of doxorubicin (DOX)-loaded liposome (DOX-Lipo) in the tumor by 2.8-fold. There were no safety concerns as the Col-NP showed no significant toxicity and reduced Col-induced damage to healthy tissues. Additionally, the number of circulating tumor cells remained unchanged after Col-NP treatment, suggesting no increased risk of tumor metastasis. Because the Col-NP acts essentially independent of the subsequent treatment, it has considerable potential for enhancing many existing delivery systems and drugs for cancer treatment. It may also be used for treating other collagen-related diseases.


Assuntos
Nanopartículas , Neoplasias , Linhagem Celular Tumoral , Colagenases/uso terapêutico , Doxorrubicina/uso terapêutico , Portadores de Fármacos/uso terapêutico , Sistemas de Liberação de Medicamentos , Humanos , Concentração de Íons de Hidrogênio , Nanomedicina , Neoplasias/tratamento farmacológico , Microambiente Tumoral
20.
Int J Mol Sci ; 22(9)2021 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-33946951

RESUMO

Flavonoid compounds are known for their antibacterial, anti-inflammatory, and anticancer properties. Therefore, they can influence membrane properties that interest us, modifying both their structure and functions. We used kaempferol (K) and myricetin (M) as representatives of this group. We investigated the influence of the abovementioned compounds on model cell membranes' properties (i.e., Langmuir monolayers and liposomes). The basic research methods used in these studies were the Langmuir method with Brewster angle microscopy and microelectrophoresis. The π-A isotherms were registered for the pure components and mixtures of these compounds with phosphatidylcholine (PC) in appropriate volume ratios. Using mathematical equations, we established that kaempferol, myricetin, and the lipids formed complexes at 1:1 ratios. We derived the parameters characterizing the formed complexes, i.e., the surfaces occupied by the complexes and the stability constants of the formed complexes. Using the microelectrophoretic method, we determined the dependence of the lipid membranes' surface charge density as a function of the pH (in the range of 2 to 10) of the electrolyte solution. The presented results indicate that the PC membrane's modification with kaempferol or myricetin affected changes in the surface charge density and isoelectric point values.


Assuntos
Derivados de Alilbenzenos/farmacologia , Dioxolanos/farmacologia , Eletroforese/métodos , Quempferóis/farmacologia , Membranas Artificiais , Microquímica/métodos , Fosfatidilcolinas/química , Lipossomas Unilamelares/química , Derivados de Alilbenzenos/química , Difusão , Dioxolanos/química , Concentração de Íons de Hidrogênio , Quempferóis/química , Microscopia de Polarização/métodos , Pressão , Refratometria , Eletricidade Estática , Propriedades de Superfície , Tensoativos , Viscosidade
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