Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27.708
Filtrar
1.
J Chromatogr A ; 1663: 462747, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-34973480

RESUMO

Free-flow isoelectric focusing (FFIEF) is a useful tool for separating and purifying proteins, DNA, cells, and organelles, etc. However, the online monitoring of each fraction during an FFIEF run has not been achieved yet, resulting in a lack of process monitoring of FFIEF. Herein, an online array ultraviolet (UV) detection system was developed for the easy assay of FFE fractions. The detector was integrated with an apparatus of FFIEF with 32 fractions to show the online monitoring, and bovine serum albumin (BSA) and lysozyme were chosen as the model proteins for manifesting the UV detector performance. The experiments revealed that (i) all the fluidic cells had good linearity from 0.03 to 10 mg/mL BSA and fair limits of detection (LODs) of 0.01 mg/mL; (ii) all the cells had good uniformity of UV absorbance; and (iii) the deviations of intra-day and inter-day of UV detector were respectively 3.8% and 5.8%, indicating the fair stability of the UV detector. The UV detector could be well used for the process monitoring of two model proteins through the whole FFIEF run, and the online absorbance assay of proteins at the end of FFIEF. The UV detector herein had the evident potential for rapid and convenient assay of protein fraction in FFIEF as well as other FFE modes.


Assuntos
Soroalbumina Bovina , Focalização Isoelétrica
2.
Biosens Bioelectron ; 200: 113914, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34973568

RESUMO

Accurate determination of procalcitonin (PCT) is highly crucial in bacterial infection diagnosis. Many biosensors previously developed suffer from large sample consumption or lengthy waiting time, which raise difficulties for more vulnerable patients, such as infants, old people, and other critically ill patients. To address this dilemma, we present an innovative boronate affinity recognition (BAR)-enhanced dynamic light scattering (DLS) biosensor to achieve ultrasensitive PCT detection. In this biosensing system, monoclonal antibody-modified magnetic nanoparticles (MNP@mAb) are designed as probes to capture PCT from serum samples and generate DLS signal transduction. Polyvalent phenylboronic acid-labeled bovine serum albumin (BSA@PBA) is used as scaffold to aggregate MNP@mAb and PCT (MNP@mAb-PCT) complex because of the specific interaction of cis-diol-containing PCT with boronic acid ligands on the surface of BSA@PBA. The BAR-enhanced DLS biosensor shows ultrahigh sensitivity to PCT determination due to high binding affinity, with the limit of detection of 0.03 pg/mL. The total detection time of PCT in whole blood or serum is less than 15 min with small sample consumption (about 1 µL) due to the rapid magnetic separation and aggregation of MNP@mAb-PCT triggered by BSA@PBA. In addition, the proposed DLS biosensor exhibits a high specificity for PCT quantitative detection. Therefore, this work provides a promising and versatile strategy for extending DLS biosensor to rapid and ultrasensitive detection of trace PCT for broader patients and more urgent cases.


Assuntos
Técnicas Biossensoriais , Difusão Dinâmica da Luz , Humanos , Limite de Detecção , Pró-Calcitonina , Soroalbumina Bovina
3.
Talanta ; 237: 122959, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736684

RESUMO

Owing to the satisfactory properties such as high specific surface area, finely tunable chemical composition, large yet adjustable pore sizes, and diverse architecture, metal-organic frameworks (MOFs) have the potential to be used as a stable, efficient, reusable and protective biomacromolecule immobilization carrier in capillary electrophoresis. Herein, a novel immobilized receptor open-tubular affinity capillary electrochromatography (OT-ACEC) strategy was developed for the first time to rapidly investigate the interactions between a set of drugs and bovine serum albumin (BSA). To further increase the amount of immobilized BSA and maintain the bioactivity of BSA, BSA was immobilized on the inner capillary surface by using polydopamine (PDA) as the adhesion layer and surface functionalization agent, a MOF namely dresden university of technology-5 (DUT-5) as supporting platform and biomacromolecule immobilization carrier, respectively. The amount of immobilized BSA on the capillary surface of the BSA@capillary and the PDA/MOFs/BSA@capillary column are separately calculated as 0.00756 nmol and 0.01812 nmol. Besides, the PDA/MOFs/BSA@capillary column was applied to investigate the interactions between BSA and flavonoids, fluoroquinolones. Under the optimal interaction conditions, three flavonoids and three fluoroquinolones are able to achieve baseline separation in the PDA/MOFs/BSA@capillary column (with resolution values of three flavonoids, 5.78 and 4.13; three fluoroquinolones, 1.72 and 1.68). The PDA/MOFs/BSA@capillary column shows good stability and reproducibility over 100 runs (relative standard deviation (RSD)<5%). In addition, the normalized capacity factor (KRCE) in this method replaced the binding constant and was used as an evaluation index to fast predict the activities of 20 drugs, some of which have not yet been reported for their interactions with BSA. Spectroscopy and molecular docking further illuminated the binding mechanism.


Assuntos
Eletrocromatografia Capilar , Estruturas Metalorgânicas , Preparações Farmacêuticas , Indóis , Simulação de Acoplamento Molecular , Polímeros , Reprodutibilidade dos Testes , Soroalbumina Bovina
4.
Talanta ; 237: 122893, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736709

RESUMO

A facile, universal and highly efficient approach for producing a self-cleaning electrochemical protein-imprinting biosensor based on dual stimuli-responsive memory hydrogels via free-radical polymerisation is described. As confirmed by static contact angle and scanning electron microscopy results, the imprinted hydrogels exhibited reversible conformational changes after being simulated by an external electric field and temperature. By exploring the properties of imprinted hydrogels for sensing applications, the electrochemical protein-imprinting biosensor was originally fabricated on a glassy carbon electrode using the drop-casting method. Because of the trigger gates of the temperature and electric field, the biosensor demonstrated excellent self-cleaning behaviours compared with other corresponding electric-field or thermo-responsive imprinting biosensors. Moreover, the prepared biosensor exhibited satisfactory selectivity, good biocompatibility, comparable limits of detection and linearity ranges as well as acceptable stability toward bovine serum albumin. Consequently, the biosensor was successfully employed to simultaneously enrich, detect and extract bovine serum albumin from complex biological samples; the process was dynamic, controllable and harmless to the template under the dual external stimuli. Thus, the proposed biosensor exhibited considerable potential in controlled drug/chemical delivery and smart sensing for bioanalyses involving dual stimuli-responsive behaviours.


Assuntos
Técnicas Biossensoriais , Impressão Molecular , Técnicas Eletroquímicas , Eletrodos , Hidrogéis , Soroalbumina Bovina
5.
Food Chem ; 372: 131280, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34818732

RESUMO

In this study, the binding mechanism between bovine serum albumin (BSA) and three gingerols ([6]-, [8]- and [10]-gingerol) was evaluated to explore an effective strategy for improving solubility and stability of gingerols. The fluorescence analysis suggested gingerols could bind with BSA to form a stable BSA/gingerols complex and [10]-gingerol had the strongest binding affinity (Ka = 4.016 × 104 L/mol) at 298 K. Thermodynamic parameters and molecular modeling validated that hydrophobic interaction and hydrogen bonds were the main driving force for the interaction of BSA/gingerols. Gingerols bound to BSA at site I (subdomain IIA) resulted in a conformational change of BSA with a structure shrinkage, which was responsible for the decrease of surface hydrophobicity. The formation of BSA/gingerols complexes promoted the solubility of [6]-, [8]- and [10]-gingerol increasing by 1.50, 6.04 and 23.50 times, respectively. In addition, the stability and antioxidant capacity of gingerols was significantly improved after binding with BSA.


Assuntos
Soroalbumina Bovina , Sítios de Ligação , Catecóis , Dicroísmo Circular , Álcoois Graxos , Simulação de Acoplamento Molecular , Ligação Proteica , Soroalbumina Bovina/metabolismo , Solubilidade , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Termodinâmica
6.
Bioorg Chem ; 118: 105467, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34781115

RESUMO

Metal-organic structures (MOF), modern extremely proliferous materials consisting of metal ions and organic coordinating molecules, has become a promising biomedical material because of its unusual features, including great surface area, wide pore volume, flexible functionality and superior performance for drug loading. In the current investigation, Gemcitabine Hydrochloride (Gem), an anticancer drug, and Amygdalin (Amy) were loaded into a nanocomposite structure formed from bovine serum albumin (BSA) as a center and zeolytic imidazolate framework-8 (ZIF-8) as a pH sensitive protective coating. The formed BSA-Gem@ZIF-8 and BSA-Gem-Amy@ZIF-8 were successively coated by polydopamine, chelated by Au3+ and conjugated via gallic acid (GA), acquired ZIF-8 structure as a multifunctional nanocarrier at the end. It was confirmed by different characterization methods that the nanocarrier was successfully produced. Due to the nature of ZIF-8, pH dependent releases of BSA-Gem@ZIF-8/Dopa/GA and BSA-Gem-Amy@ZIF-8/Dopa/GA were observed in in vitro studies. Cytotoxicity and apoptotic effects of these nanocarriers were evaluated using WST-1 and acridine orange staining in MCF-7 human breast cancer and HUVEC control cell lines. In-vitro cytotoxicity studies showed that both BSA-Gem@ZIF-8/Dopa/GA and BSA-Gem-Amy@ZIF-8/Dopa/GA were more effective than gemcitabine alone in MCF-7 cells with less toxicity in HUVEC cells. Additionally, both pH-responsive nanocarriers induced more apoptotic cell death in MCF-7 cells. We therefore believe that the built multifunctional nanocarrier based on ZIF-8 could be an alternative therapeutic strategy the use of gemcitabine for cancer therapy.


Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Materiais Biocompatíveis/química , Desoxicitidina/análogos & derivados , Dopamina/química , Sistemas de Liberação de Medicamentos , Estruturas Metalorgânicas/química , Soroalbumina Bovina/química , Animais , Antimetabólitos Antineoplásicos/química , Bovinos , Proliferação de Células/efeitos dos fármacos , Desoxicitidina/química , Desoxicitidina/farmacologia , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Concentração de Íons de Hidrogênio , Células MCF-7 , Estrutura Molecular , Relação Estrutura-Atividade , Células Tumorais Cultivadas
7.
Food Chem ; 375: 131893, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34954575

RESUMO

The influence of cholesterol (CHO), bovine serum albumin (BSA) and lactoferrin (LF), on the phase transition temperature (Tm) and structure of DPPC liposomes during in vitro digestion was investigated using Dynamic Laser Scattering (DLS) and Fourier Transform Infrared Spectroscopy technologies (FTIR). CHO enhanced bilayers thickness and acyl chain order, especially in DPPC:CHO of 6:1, with the average size increase to 1.77 ± 0.20 µm and broaden of phase transition (Tm 45.8 °C). Protein critically impacted on the liposomal structure through formation of hydrogen bonds between in DPPC and protein. Liposomal size and Tm were significantly changed after simulated gastric digestion, whereas the pancreatic incubation can broaden transition phase and weaken functional groups of liposomes. Our data provided a better understanding on structure changes of CHO-containing membrane and protein addition by revealing Tm and chemical bonds details, and added to current knowledge for evaluating the different component on liposomal digestibility in food area.


Assuntos
Colesterol , Lipossomos , Digestão , Difusão Dinâmica da Luz , Soroalbumina Bovina , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Biochim Biophys Acta Mol Basis Dis ; 1868(1): 166283, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34601015

RESUMO

Advanced glycation end products (AGEs) play a critical pathogenic role in the development of diabetic complications. Recent studies have shown that diabetes is associated with not only abnormal glucose metabolism but also abnormal ribose and fructose metabolism, although glucose is present at the highest concentration in humans. The glycation ability and contribution of ribose and fructose to diabetic complications remain unclear. Here, the glycation ability of ribose, fructose and glucose under a mimic physiological condition, in which the concentration of ribose or fructose was one-fiftieth that of glucose, was compared. Bovine serum albumin (BSA) was used as the working protein in our experiments. Ribose generated more AGEs and was markedly more cytotoxic to SH-SY5Y cells than fructose. The first-order rate constant of ribose glycation was found to be significantly greater than that of fructose glycation. LC-MS/MS analysis revealed 41 ribose-glycated Lys residues and 12 fructose-glycated residues. Except for the shared Lys residues, ribose reacted selectively with 17 Lys, while no selective Lys was found in fructose-glycated BSA. Protein conformational changes suggested that ribose glycation may induce BSA into amyloid-like monomers compared with fructose glycation. The levels of serum ribose were correlated positively with glycated serum protein (GSP) and diabetic duration in type 2 diabetes mellitus (T2DM), respectively. These results indicate that ribose has a greater glycation ability than fructose, while ribose largely contributes to the production of AGEs and provides a new insight to understand in the occurrence and development of diabetes complications.


Assuntos
Complicações do Diabetes/sangue , Diabetes Mellitus Tipo 2/sangue , Produtos Finais de Glicação Avançada/genética , Soroalbumina Bovina/metabolismo , Animais , Bovinos , Cromatografia Líquida , Complicações do Diabetes/metabolismo , Complicações do Diabetes/patologia , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patologia , Frutose/sangue , Glucose/metabolismo , Produtos Finais de Glicação Avançada/metabolismo , Glicosilação , Humanos , Ribose/sangue , Espectrometria de Massas em Tandem
9.
Food Chem ; 366: 130422, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34392082

RESUMO

Tea cream, produced by interactions among tea ingredients, is undesirable in tea beverage industry. The interaction between bovine serum albumin (BSA) and theaflavin-3,3'-digallate (TFDG, an important component in tea cream and functional substance of black tea) was investigated by fluorescence spectroscopy, ultraviolet-visible (UV-vis) absorption spectroscopy, synchronous fluorescence spectroscopy, fourier-transform infrared (FT-IR) spectroscopy, and molecular docking technique. Multi-spectroscopic experiments demonstrated that TFDG interacted with BSA via static quenching, and the microenvironment around BSA became more hydrophobicity. FT-IR showed that the α-helix of BSA was increased when binding with TFDG. Thermodynamic parameters and molecular docking demonstrated that hydrophobic interactions and hydrogen bonds dominated the interaction between TFDG and BSA. The mechanism proposed in this research could further develop some nanoparticles to excellent biochemical properties while reducing the formation of tea cream, and explore the potential of BSA as transport carrier for TFDG.


Assuntos
Soroalbumina Bovina , Biflavonoides , Sítios de Ligação , Catequina/análogos & derivados , Dicroísmo Circular , Simulação de Acoplamento Molecular , Ligação Proteica , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
10.
Food Chem ; 368: 130651, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34392117

RESUMO

Bovine serum albumin (BSA) and BSA-glucose conjugates (GBSAⅠ and GBSAⅠI) with different extent of glycation were complexed with curcumin (CUR). The formation mechanism of BSA/GBSA-CUR complexes and the effect of glycation on their physicochemical properties were investigated. Fluorescence quenching and FTIR analysis indicated that the BSA/GBSA-CUR nanocomplexes were formed mainly by hydrophobic interactions. XRD analysis demonstrated that CUR was present in an amorphous state in the nanocomplexes. BSA with a greater extent of glycation (BSA < GBSAⅠ

Assuntos
Curcumina , Glicosilação , Interações Hidrofóbicas e Hidrofílicas , Soroalbumina Bovina
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120261, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34419830

RESUMO

Bovine serum albumin (BSA) has been used as a transporter protein for levothyroxine (LT4) and rutin, due to its property of binding to various ligands. Rutin binding to the BSA-LT4 complex can bring many benefits due to its proven pharmacological properties. Using Fourier-Transform Infrared Spectroscopy (FT-IR) the changes induced by rutin in the structure of BSA-LT4 complex were determined. Fluorescence studies allowed us to determine the quenching mechanism and affinity of rutin to the BSA-LT4 complex. The thermodynamic parameters suggest the binding of rutin to BSA-LT4 is a spontaneous process, driven by enthalpy and electrostatic forces. Also, the second derivative of the emission spectra suggests the Trp's of BSA are located in two different microenvironments. Thermal and chemical denaturation of BSA-LT4-rutin complex presents similar behavior but with better stability of the complex in case of chemical denaturation. Molecular docking studies show the binding of the two ligands to the same BSA site, suggesting that rutin may influence the bond of LT4 with the protein. Studies on the antioxidant activity of the BSA-LT4-rutin complex suggest that the presence of LT4 decreases the antioxidant activity of the rutin, but even so this antioxidant activity can be used to bring benefits for medical purposes.


Assuntos
Rutina , Soroalbumina Bovina , Sítios de Ligação , Simulação de Acoplamento Molecular , Ligação Proteica , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Tiroxina
12.
Food Chem ; 368: 130902, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34438176

RESUMO

Overcoming harsh gastric environment is still a challenging to bioactive proteins, microencapsulation provides one strategy in designing this protection barrier. In this work, bovine serum albumin and ovalbumin were chosen as model proteins, while polylysine-alginate complex was fabricated for microencapsulation purpose. Both of the protein-loaded microcapsules had regular internal microstructures. The model protein's embedding increased the thermal stability of the microcapsules. Both of the protein-loaded microcapsules had a slow release rate in simulated gastric fluids (pH 3.0), while a sustained release profile in simulated intestinal fluids (pH 6.4), indicating an excellent tolerance to the acidic gastric environment. The microencapsulation process was mild and had no influence on the protein's molecular weight, while a slight peak shifting occurred in the secondary structure of the released proteins. The developed microcapsules could be explored as a kind of vehicle for bioactive proteins applied in functional foods, health care products and medical formulations.


Assuntos
Polilisina , Soroalbumina Bovina , Alginatos , Cápsulas , Ovalbumina
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120306, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34461524

RESUMO

Discrimination of human serum albumin (HSA) from bovine serum albumin (BSA) based on the fluorescence probe technique is still challenging due to similar chemical structures. In this work, a novel flavonoid-based fluorescent probe AF is reported for successful discrimination of HSA from BSA. The sensing performances of probe, including sensing dynamic, sensitivity and selectivity, have been carefully studied. Moreover, sensing mechanism was elucidated by Job's plot, displacement experiment, and molecular docking, suggesting that the specific response to HSA originated from the albumin-induced restricted intramolecular rotation (RIR) of probe. This work may provide a simple way for designing of novel probes for HSA with high selectivity.


Assuntos
Soroalbumina Bovina , Albumina Sérica Humana , Flavonoides , Humanos , Simulação de Acoplamento Molecular , Ligação Proteica , Albumina Sérica Humana/metabolismo , Espectrometria de Fluorescência
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120298, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34464920

RESUMO

Dapagliflozin (DAPA) is a selective sodium-glucose cotransporter-2 inhibitor that reduces renal glucose reabsorption. The drug has recently become a crucial milestone in the management of diabetes and heart failure. In this study, the interaction of DAPA with bovine serum albumin (BSA) was investigated for the first time using various fluorescence spectroscopic techniques, UV-absorption spectroscopy, molecular docking, and molecular dynamic (MD) simulation. The fluorescence spectroscopic titration study performed at different temperatures showed that DAPA quenched the fluorescence of BSA through a combination of dynamic and static mechanisms, which was confirmed by UV absorption, fluorescence-resonance energy transfer measurements, and MD simulation. The binding thermodynamic parameters demonstrated that the binding stoichiometry between BSA and DAPA was 1:1. Competitive binding experiments using site-specific markers as well as molecular docking studies showed that DAPA binds to site I on BSA. The positive values of enthalpy change (ΔH) and entropy change (ΔS) revealed that hydrophobic forces played a predominant role in the binding of DAPA to BSA, whereas the negative value of Gibbs free energy change (ΔG) indicated the spontaneity of the interaction. Moreover, the synchronous fluorescence spectroscopy has shown that DAPA binding to the protein molecule occurs in the vicinity of the tryptophan residue. These findings were confirmed by the molecular docking and MD simulation studies.


Assuntos
Diabetes Mellitus Tipo 2 , Inibidores do Transportador 2 de Sódio-Glicose , Compostos Benzidrílicos , Sítios de Ligação , Glucosídeos , Humanos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Termodinâmica
15.
J Colloid Interface Sci ; 608(Pt 1): 255-264, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34626972

RESUMO

The adhesion force evolution of protein on surfaces with continuously varied hydrophobicity/hydration layer has not been completely clarified yet, limiting the further development of environmental applications such as membrane anti-biofouling and selective adsorption of the functional surfaces. Herein, chemical force spectroscopy using atomic force microscopy (AFM) was utilized to quantify the evolution of the adhesion forces of protein on hydration surfaces in water, where bovine serum albumin (BSA) was immobilized on an AFM tip as the representative protein. The stiffness, roughness and charge properties of the substrate surfaces were kept constant and the hydrophobicity was the only variant to monitor the role of hydrated water layers in protein adhesion. The adhesion force increased non-monotonically as a function of hydrophobicity of substrate surfaces, which was related to the concentration of humic acid, and independent of pH values and ionic strength. The non-monotonic variation occurred in the range of contact angle at 60-80° due to the mutual restriction between solid-liquid interface energy and solid-solid interface energy. Hydrophobic attraction was the dominant force that drove adhesion of BSA to these model substrate surfaces, but the passivation of hydration layers at the interface could weaken the hydrophobic attraction. In contrast to the measurements in water, the adhesion forces decreased as a function of surface hydrophobicity when measured in air, because capillary forces from condensation water dominated adhesion forces. The passivation of hydration layers of protein was revealed by quantitatively determining the evolution of adhesion forces on the hydration surfaces of varying hydrophobicity, which was ignored by traditional adhesion theory.


Assuntos
Soroalbumina Bovina , Adsorção , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica , Propriedades de Superfície
16.
Biosens Bioelectron ; 196: 113705, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34715535

RESUMO

A visualization method for the qualitative evaluation of soybean isoflavones secreted from soybean roots by transferring them onto a sheet with immobilized bovine serum albumin (BSA) was developed. BSA was chemically bonded onto a glass microfiber filter. The fluorescence quenching resulting from the interaction of BSA with soybean isoflavones such as daidzein and daidzin was utilized. Fluorescence images before and after soybean roots were placed in contact with the sheets with immobilized BSA were taken with an electron-multiplying charge-coupled device camera. The fluorescence quenching in the images was visualized and analyzed. Soybean isoflavones were extracted from the sheets for quantitative analysis, and the correlation coefficient between the quenched fluorescence intensity per sheet and the total amount of soybean isoflavones was 0.78 (p < 0.01), indicating a high correlation. The quenched fluorescence intensity was lower in pumpkin roots, which do not secrete soybean isoflavone. It was found from analyzed images that soybean isoflavone is secreted in larger amounts from the basal region of the taproot and the tips of the lateral roots of soybean.


Assuntos
Técnicas Biossensoriais , Isoflavonas , Raízes de Plantas , Soroalbumina Bovina , Soja
17.
ChemistryOpen ; 10(12): 1251-1259, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34907672

RESUMO

The synthesis and characterization of amino-functionalized mesoporous silica nanoparticles are presented following two different synthetic methods: co-condensation and post-synthesis grafting of 3-aminopropyltriethoxysilane. The amino groups' distribution on the mesoporous silica nanoparticles was evaluated considering the aggregation state of a grafted photosensitizer (Verteporfin) by using spectroscopic techniques. The homogeneous distribution of amino groups within the silica network is a key factor to avoid aggregation during further organic functionalization and to optimize the performance of functionalized silica nanoparticles in biomedical applications. In addition, the formation of a protein corona on the external surface of both bare and amino-functionalized mesoporous silica was also investigated by adsorbing Bovine Serum Albumin (BSA) as a model protein. The adsorption of BSA was found to be favorable, reducing the aggregation phenomena for both bare and amino-modified nanoparticles. Nevertheless, the dispersant effect of BSA was much more evident in the case of amino-modified nanoparticles, which reached monodispersion after adsorption of the protein, thus suggesting that amino-modified nanoparticles can benefit from protein corona formation for preventing severe aggregation in biological media.


Assuntos
Nanopartículas , Dióxido de Silício , Adsorção , Soroalbumina Bovina
18.
Analyst ; 146(23): 7126-7130, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34723292

RESUMO

Recently, gold nanoclusters (AuNCs) have received considerable scientific interest due to their ability to generate intrinsic photoluminescence (PL), making them suitable for a wide range of applications, such as sensing, biolabeling and bioimaging. Fluorescence lifetime imaging microscopy (FLIM) is an extremely promising technique when it comes to tissue imaging, especially once combined with near-infrared two-photon excitation (TPE) due to deep tissue penetration and improved spatial resolution. In this paper, we carried out an innovative study on the ability of bovine serum albumin stabilized gold nanoclusters (BSA-AuNCs) to perform as reliable label-free contrast agents for the visualization of tissue-like agarose phantoms via TPE-FLIM. We prove that BSA-AuNCs exhibit uniform and reproducible TPE PL in the first biological window, when embedded in phantoms, under 820 nm excitation provided by a Ti:Sapphire pulsed laser. The two-photon origin of the emission signal inside the phantom is demonstrated by the quadratic dependence of the PL intensity on the excitation power. Moreover, we focused on the evaluation of BSA-AuNCs' potential as contrast agents at different concentrations inside phantoms, simulating an ex vivo environment, at three NIR excitation wavelengths, in view of defining the optimal experimental conditions for future real-tissue imaging assays. The present study aims at translating our previous results on the successful performance of BSA-AuNCs as contrast agents for in vitro FLIM imaging, using visible light, towards non-invasive ex vivo NIR imaging applications. Besides the advantageous use of the combined techniques TPE-FLIM, the novelty of our work consists of demonstrating for the first time the capacity of BSA-AuNCs to perform as bright contrast agents inside cancer-tissue mimicking phantoms. We prove that BSA-AuNCs show great promise as fluorescent contrast agents for TPE-FLIM towards image-assisted tumor surgery.


Assuntos
Ouro , Nanopartículas Metálicas , Meios de Contraste , Imagem Óptica , Soroalbumina Bovina
19.
Soft Matter ; 17(42): 9682-9688, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34633019

RESUMO

The formation of protein gel networks in aqueous systems is a result of protein intermolecular interactions after an energy input, like heating. In this research, we report that a redox reaction between Au3+ ions and proteins can also lead to the formation of a protein gel network. Amino acids, like cysteine and tyrosine, get oxidized and form covalent bonds with neighboring protein molecules, while Au3+ ions get reduced to Au+ and Au0, nucleate and form gold nanoparticles. The protein gel network formation occurs within 2 h at room temperature and can be tuned by varying Au3+/protein ratio and accelerated by increasing the incubation temperature. The proposed Au3+-induced gel network formation was applied to different proteins, like egg yolk high-density lipoprotein, bovine serum albumin and whey protein. This research opens new insights for the investigation of the metal-protein interactions and may aid in the design of novel hybrid-soft nanocomposite materials.


Assuntos
Ouro , Nanopartículas Metálicas , Aminoácidos , Cisteína , Soroalbumina Bovina
20.
Biochemistry ; 60(42): 3200-3212, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34633183

RESUMO

Fatty acid photodecarboxylase (FAP), one of the few natural photoenzymes characterized so far, is a promising biocatalyst for lipid-to-hydrocarbon conversion using light. However, the optimum supramolecular organization under which the fatty acid (FA) substrate should be presented to FAP has not been addressed. Using palmitic acid embedded in phospholipid liposomes, phospholipid-stabilized microemulsions, and mixed micelles, we show that FAP displays a preference for FAs present in liposomes and at the surface of microemulsions. The kinetics of adsorption onto phospholipid and galactolipid monomolecular films further suggests the ability of FAP to bind to and penetrate into membranes, with a higher affinity in the presence of FAs. The FAP structure reveals a potential interfacial recognition site with clusters of hydrophobic and basic residues surrounding the active site entrance. The resulting dipolar moment suggests the orientation of FAP at negatively charged interfaces. These findings provide important clues about the mode of action of FAP and the development of FAP-based bioconversion processes.


Assuntos
Proteínas de Algas/química , Carboxiliases/química , Adsorção , Animais , Biocatálise , Bovinos , Chlorella/enzimologia , Emulsões/química , Cinética , Micelas , Ácido Palmítico/química , Soroalbumina Bovina/química , Lipossomas Unilamelares/química , Água/química , beta-Ciclodextrinas/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...