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1.
Langmuir ; 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38329721

RESUMO

The coexistence of lead, zinc, and copper ions in wastewater constitutes an environmental challenge of pressing concern. This research delves into the preparation of innovative oxidation-doped conjugated microporous poly(aniline) frameworks, exploring their prospective efficacy in regulating lead ion adsorption from aqueous solutions. H2SO4-CMPTA demonstrates the capability to reach adsorption equilibrium within 15 min at a lead concentration of 50 ppm. Even at a lead concentration of 20 ppm, it still efficaciously attenuates these levels to sub-10 ppb, a value surpassing extant standard. H2SO4-CMPTA retains over 78.8% adsorption efficiency after six cycles. Analytical characterization coupled with computational calculations suggests that sulfate-coordinated nitrogen cationic structure plays a crucial role in adsorption. A deeper investigation reveals the cardinal role of electrostatic attraction and exclusive chelation adsorption underpinning the efficient capture of lead ions by doped sulfate ions. Intriguingly, in a mixed heavy metal solution containing lead, zinc, and copper ions, H2SO4-CMPTA exhibits an initial predilection toward zinc ions, yet an eventual ion-exchange adsorption gravitating toward lead ions was discerned, governed by the latter's superior binding energy. Our study elucidates a promising material as an efficacious tool for the remediation of aquatic environments tainted with lead contaminants.

2.
Angew Chem Int Ed Engl ; 60(6): 2924-2928, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33107179

RESUMO

Synthetic routes for heteroatom-containing polycyclic aromatic hydrocarbons (H-PAHs) with alkyl and aryl substitution are demonstrated. Three H-PAHs, including heteroatom-containing rubicenes (H-rubicenes), angular-benzothiophenes (ABTs), and indenothiophene (IDTs) were successfully synthesized by two key steps, including polysubstituted olefin formation and cyclization. Specifically, ABT and H-rubicenes were comprehensively investigated by single-crystal X-ray diffraction, NMR spectroscopy, UV-vis absorption, cyclic voltammetry, transient absorption, and single-crystal OFET measurements.

3.
Small ; 16(17): e2000909, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32249500

RESUMO

Various organic nanoagents have been developed for photothermal therapy (PTT) and photodynamic therapy (PDT) under near-infrared (NIR) irradiation. Among them, small molecule-based nanoagents are very attractive due to their advantages of well-defined chemical structures, high purity, good reproducibility, and easy processability. However, only a few small molecule-based nanoagents have been developed for PDT under NIR irradiation. Moreover, the mechanism of PDT under NIR is still elusive. Herein, a semiconducting small molecule (BTA) with donor-acceptor-donor structure and twisted conformation is developed for PDT/PTT under NIR irradiation. A large π-conjugated electron-deficient unit is used as the core to couple with two electron-donating units, ensuring the strong absorption under 808 nm. Moreover, the donor-acceptor structures and twisted conformation can reduce the energy gap between the singlet and triplet states (∆EST ) to afford effective intersystem crossing, beneficial for reactive oxygen species generation. The mechanism is probed by experimental and theoretical evidence. Moreover, the BTA nanoparticles exhibit excellent biocompatibility and PTT/PDT in vitro performance under NIR irradiation. This provides a strategy for designing highly efficient PDT/PTT molecular materials.


Assuntos
Nanopartículas , Fotoquimioterapia , Terapia Fototérmica , Semicondutores , Raios Infravermelhos , Fotoquimioterapia/métodos , Terapia Fototérmica/métodos
4.
Chemistry ; 26(55): 12510-12522, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32246541

RESUMO

In recent decades, non-fullerene acceptors (NFAs) are undergoing rapid development and emerging as a hot area in the field of organic solar cells. Among the high-performance non-fullerene acceptors, aromatic diimide-based electron acceptors remain to be highly promising systems. This review discusses the important progress of perylene diimide (PDI)-based polymers as non-fullerene acceptors in all-polymer solar cells (all-PSCs) since 2014. The relationship between structure and property, matching aspects between donors and acceptors, and device fabrications are unveiled from a synthetic chemist perspective.

5.
Angew Chem Int Ed Engl ; 59(31): 12756-12761, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32343868

RESUMO

Cancer possesses normoxic and hypoxia microenvironments with different levels of oxygen, needing different efficacies of photothermal and photodynamic therapies. It is important to precisely tune the photothermal and photodynamic effects of phototherapy nano-agents for efficient cancer treatment. Now, a series of copolymeric nanoparticles (PPy-Te NPs) were synthesized in situ by controlled oxidative copolymerization with different ratios of pyrrole to tellurophene by FeCl3 . The photothermal and photodynamic effects of semiconducting nano-agents under the first near-infrared (NIR) irradiation were precisely and systematically tuned upon simply varying the molar ratio of the pyrrole to tellurophene. The PPy-Te NPs were used for cancer treatment in mice, exhibiting excellent biocompatibility and therapeutic effect. This work presents a simple method to tune photothermal and photodynamic therapies effect in semiconducting nano-agents for cancer treatment.


Assuntos
Antineoplásicos/uso terapêutico , Nanopartículas/uso terapêutico , Neoplasias/tratamento farmacológico , Fármacos Fotossensibilizantes/uso terapêutico , Polímeros/uso terapêutico , Pirróis/uso terapêutico , Animais , Antineoplásicos/síntese química , Antineoplásicos/efeitos da radiação , Linhagem Celular Tumoral , Raios Infravermelhos , Camundongos , Nanopartículas/química , Nanopartículas/efeitos da radiação , Fotoquimioterapia , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/efeitos da radiação , Terapia Fototérmica , Polimerização , Polímeros/síntese química , Polímeros/efeitos da radiação , Pirróis/síntese química , Pirróis/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo
6.
Angew Chem Int Ed Engl ; 59(35): 15043-15049, 2020 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-32385920

RESUMO

Triplet acceptors have been developed to construct high-performance organic solar cells (OSCs) as the long lifetime and diffusion range of triplet excitons may dissociate into free charges instead of net recombination when the energy levels of the lowest triplet state (T1 ) are close to those of charge-transfer states (3 CT). The current triplet acceptors were designed by introducing heavy atoms to enhance the intersystem crossing, limiting their applications. Herein, two twisted acceptors without heavy atoms, analogues of Y6, constructed with large π-conjugated core and D-A structure, were confirmed to be triplet materials, leading to high-performance OSCs. The mechanism of triplet excitons were investigated to show that the twisted and D-A structures result in large spin-orbit coupling (SOC) and small energy gap between the singlet and triplet states, and thus efficient intersystem crossing. Moreover, the energy level of T1 is close to 3 CT, facilitating the split of triplet exciton to free charges.

7.
Chemphyschem ; 20(20): 2600-2607, 2019 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-31179624

RESUMO

Tellurophene-based small molecules and polymers have received great attentions owing to their applications in thin-film transistors, solar cells, and sensors. This article reviews the current progress of the synthesis and applications of tellurophene-based small molecules and polymers. The physicochemical properties and optoelectronic applications of tellurophene-based materials are summarized and discussed. In the end, the challenges and outlook of tellurophene-based materials are presented.

8.
Inorg Chem ; 57(15): 9266-9273, 2018 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-29989396

RESUMO

The C═S double bonds in CS2 and thioketones were catalytically cleaved by Pd dimeric complexes [(N∧N)2Pd2(NO3)2](NO3)2 (N∧N, 2,2'-bipyridine, 4,4'-dimethylbipyridine or 4,4'-bis(trifluoromethyl)) at room temperature in one pot to afford CO2 and ketones, respectively, for the first time. The mechanisms were fully investigated by kinetic NMR, isotope-labeled experiments, in situ ESI-MS, and DFT calculations. The reaction is involved a hydrolytic desulfurization process to generate C═O double bonds and a trinuclear cluster, which plays a pivotal role in the catalytic cycle to regenerate the dimeric catalysts with HNO3. Furthermore, the electronic properties of catalyst ligands possess significant influence on reaction rates and kinetic parameters. At the same temperature, the reaction rate is consistent with the order of electronegativity of N∧N ligands (4,4'-bis(trifluoromethyl) > 2,2'-bipyridine > 4,4'-dimethylbipyridine). This homogeneous catalytic reaction features mild conditions, a broad substrate scope, and operational simplicity, affording insight into the mechanism of catalytic activation of carbon sulfur bonds.

9.
Nat Mater ; 14(6): 636-42, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25849532

RESUMO

The remarkable performance of lead halide perovskites in solar cells can be attributed to the long carrier lifetimes and low non-radiative recombination rates, the same physical properties that are ideal for semiconductor lasers. Here, we show room-temperature and wavelength-tunable lasing from single-crystal lead halide perovskite nanowires with very low lasing thresholds (220 nJ cm(-2)) and high quality factors (Q ∼ 3,600). The lasing threshold corresponds to a charge carrier density as low as 1.5 × 10(16) cm(-3). Kinetic analysis based on time-resolved fluorescence reveals little charge carrier trapping in these single-crystal nanowires and gives estimated lasing quantum yields approaching 100%. Such lasing performance, coupled with the facile solution growth of single-crystal nanowires and the broad stoichiometry-dependent tunability of emission colour, makes lead halide perovskites ideal materials for the development of nanophotonics, in parallel with the rapid development in photovoltaics from the same materials.

10.
Phys Rev Lett ; 117(6): 067601, 2016 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-27541475

RESUMO

Many chalcogenide glasses undergo a breakdown in electronic resistance above a critical field strength. Known as threshold switching, this mechanism enables field-induced crystallization in emerging phase-change memory. Purely electronic as well as crystal nucleation assisted models have been employed to explain the electronic breakdown. Here, picosecond electric pulses are used to excite amorphous Ag_{4}In_{3}Sb_{67}Te_{26}. Field-dependent reversible changes in conductivity and pulse-driven crystallization are observed. The present results show that threshold switching can take place within the electric pulse on subpicosecond time scales-faster than crystals can nucleate. This supports purely electronic models of threshold switching and reveals potential applications as an ultrafast electronic switch.

11.
J Am Chem Soc ; 137(5): 2089-96, 2015 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-25602495

RESUMO

Recent discoveries of highly efficient solar cells based on lead iodide perovskites have led to a surge in research activity on understanding photo carrier generation in these materials, but little is known about trap states that may be detrimental to solar cell performance. Here we provide direct evidence for hole traps on the surfaces of three-dimensional (3D) CH3NH3PbI3 perovskite thin films and excitonic traps below the optical gaps in these materials. The excitonic traps possess weak optical transition strengths, can be populated from the relaxation of above gap excitations, and become more significant as dimensionality decreases from 3D CH3NH3PbI3 to two-dimensional (2D) (C4H9NH3I)2(CH3NH3I)(n-1)(PbI2)(n) (n = 1, 2, 3) perovskites and, within the 2D family, as n decreases from 3 to 1. We also show that the density of excitonic traps in CH3NH3PbI3 perovskite thin films grown in the presence of chloride is at least one-order of magnitude lower than that grown in the absence of chloride, thus explaining a widely known mystery on the much better solar cell performance of the former. The trap states are likely caused by electron-phonon coupling and are enhanced at surfaces/interfaces where the perovskite crystal structure is most susceptible to deformation.

12.
Iran J Kidney Dis ; 17(4): 191-198, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37634245

RESUMO

INTRODUCTION: This study was conducted to determine the factors affecting the development of sarcopenias in elderly patients with chronic kidney disease (CKD), in order to provide future clinical reference and guidance in preventing the occurrence of sarcopenias in patients with CKD. METHODS: We included 116 CKD patients admitted to affiliated Hospital of Hebei University for retrospective analysis between September 2019 and March 2022. Fifty-one CKD patients with sarcopenias were selected as the observation group (OG) and 65 CKD patients without sarcopenias were considered as the control group (CG). Clinical baseline data such as age and sex were recorded, venous blood was collected for routine examination, and a multi-frequency body composition analyzer was applied to measure patients' body composition. Grip strength, middle arm circumstances (MAC) and triceps skin-fold thickness (TSF) were also measured. Then, patients' sleep quality, nutritional status and negative psychological status were assessed by using the Pittsburgh Sleep Quality Index (PSQI), Malnutrition inflammation score (MIS), and Self-rating Anxiety/Depression Scale (SAS/SDS), respectively. Differences in test results were compared inter-group, and the factors affecting the occurrence of sarcopenias in CKD patients were analyzed by multiple Logistic regression. RESULTS: OG patients were older than CG patients, with a higher number of female patients. Their BMI, bone mass, MAC, serum creatinine (Scr), uric acid (UA) and triglyceride (TG) were lower (P < .05). According to multiple Logistic regression analysis, age, as well as PSQI, MIS, SAS, and SDS scores were the risk factors for sarcopenias in CKD, while BMI, bone mass, MAC, Scr, UA and TG were protective factors (P < .05). CONCLUSION: Age, poor sleep quality, poor nutritional status and negative emotions are independent risk factors for sarcopenias in CKD patients, while BMI, bone mass, MAC, UA, TG, and Scr are independent protective factors.  DOI: 10.52547/ijkd.7537.


Assuntos
Sarcopenia , Idoso , Humanos , Feminino , Sarcopenia/diagnóstico , Sarcopenia/epidemiologia , Estudos Retrospectivos , Composição Corporal , Densidade Óssea , Força da Mão , Inflamação
13.
Front Oncol ; 12: 1050288, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36620557

RESUMO

Background: Stomach adenocarcinoma (STAD) arises from the mutations of stomach cells and has poor overall survival. Chemotherapy is commonly indicated for patients with stomach cancer following surgical resection. The most prevalent alteration that affects cancer growth is N6-methyladenosine methylation (m6A), although the possible function of m6A in STAD prognosis is not recognized. Method: The research measured predictive FRGs in BLCA samples from the TCGA and GEO datasets. Data on the stemness indices (mRNAsi), gene mutations, copy number variations (CNV), tumor mutation burden (TMB), and corresponding clinical characteristics were obtained from TCGA and GEO. STAD from TCGA and GEO at 24 m6A was investigated. Lasso regression was used to construct the prediction model to assess the m6A prognostic signals in STAD. In addition, the correlation between m6a and immune infiltration in STAD patients was discussed using GSVA and ssGSEA analysis. Based on these genes, GO and KEGG analyses were performed to identify key biological functions and key pathways. Result: A significant relationship was discovered between numerous m6A clusters and the tumor immune microenvironment, as well as three m6A alteration patterns with different clinical outcomes. Furthermore, GSVA and ssGSEA showed that m6A clusters were significantly associated with immune infiltration in the STAD. The low-m6Ascore group had a lower immunotherapeutic response than the high-m6Ascore group. ICIs therapy was more effective in the group with a higher m6Ascore. Three writers (VIRMA, ZC3H13, and METTL3) showed significantly lower expression, whereas five authors (METTL14, METTL16, WTAP, RBM15, and RBM15B) showed considerably higher expression. Three readers (YTHDC2, YTHDF2, and LRPPRC) had higher levels of expression, whereas eleven readers (YTHDC1, YTHDF1, YTHDF3, HNRNPC, FMR1, HNRNPA2B1, IGFBP1, IGFBP2, IGFBP3, and RBMX) had lower levels. As can be observed, the various types of m6 encoders have varied ramifications for STAD control. Conclusion: STAD occurrence and progression are linked to m6A-genes. Corresponding prognostic models help forecast the prognosis of STAD patients. m6A-genes and associated immune cell infiltration in the tumor microenvironment (TME) may serve as potential therapeutic targets in STAD, which requires further trials. In addition, the m6a-related gene signature offers a viable alternative to predict bladder cancer, and these m6A-genes show a prospective research area for STAD targeted treatment in the future.

14.
Front Oncol ; 12: 938413, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35898876

RESUMO

Objective: This study aimed to evaluate a convolution neural network algorithm for breast lesion detection with multi-center ABUS image data developed based on ABUS image and Yolo v5. Methods: A total of 741 cases with 2,538 volume data of ABUS examinations were analyzed, which were recruited from 7 hospitals between October 2016 and December 2020. A total of 452 volume data of 413 cases were used as internal validation data, and 2,086 volume data from 328 cases were used as external validation data. There were 1,178 breast lesions in 413 patients (161 malignant and 1,017 benign) and 1,936 lesions in 328 patients (57 malignant and 1,879 benign). The efficiency and accuracy of the algorithm were analyzed in detecting lesions with different allowable false positive values and lesion sizes, and the differences were compared and analyzed, which included the various indicators in internal validation and external validation data. Results: The study found that the algorithm had high sensitivity for all categories of lesions, even when using internal or external validation data. The overall detection rate of the algorithm was as high as 78.1 and 71.2% in the internal and external validation sets, respectively. The algorithm could detect more lesions with increasing nodule size (87.4% in ≥10 mm lesions but less than 50% in <10 mm). The detection rate of BI-RADS 4/5 lesions was higher than that of BI-RADS 3 or 2 (96.5% vs 79.7% vs 74.7% internal, 95.8% vs 74.7% vs 88.4% external). Furthermore, the detection performance was better for malignant nodules than benign (98.1% vs 74.9% internal, 98.2% vs 70.4% external). Conclusions: This algorithm showed good detection efficiency in the internal and external validation sets, especially for category 4/5 lesions and malignant lesions. However, there are still some deficiencies in detecting category 2 and 3 lesions and lesions smaller than 10 mm.

15.
Biotechnol Biofuels ; 14(1): 174, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34461979

RESUMO

BACKGROUND: Isobutanol is an attractive biofuel with many advantages. Third-generation biorefineries that convert CO2 into bio-based fuels have drawn considerable attention due to their lower feedstock cost and more ecofriendly refining process. Although autotrophic cyanobacteria have been genetically modified for isobutanol biosynthesis, there is a lack of stable and convenient strategies to improve their production. RESULTS: In this study, we first engineered Synechococcus elongatus for isobutanol biosynthesis by introducing five exogenous enzymes, reaching a production titer of 0.126 g/L at day 20. It was then discovered that high salinity stress could result in a whopping fivefold increase in isobutanol production, with a maximal in-flask titer of 0.637 g/L at day 20. Metabolomics analysis revealed that high salinity stress substantially altered the metabolic profiles of the engineered S. elongatus. A major reason for the enhanced isobutanol production is the acceleration of lipid degradation under high salinity stress, which increases NADH. The NADH then participates in the engineered isobutanol-producing pathway. In addition, increased membrane permeability also contributed to the isobutanol production titer. A cultivation system was subsequently developed by mixing synthetic wastewater with seawater to grow the engineered cyanobacteria, reaching a similar isobutanol production titer as cultivation in the medium. CONCLUSIONS: High salinity stress on engineered cyanobacteria is a practical and feasible biotechnology to optimize isobutanol production. This biotechnology provides a cost-effective approach to biofuel production, and simultaneously recycles chemical nutrients from wastewater and seawater.

16.
Sci Bull (Beijing) ; 65(18): 1580-1586, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-36738076

RESUMO

It is important to regulate the concentration of reactive oxygen species (ROS) in cells since they play important roles in metabolism. Thus, developing nanoreagents to control the ROS is critical. Herein, tellurium-doped carbon quantum dots (Te-CDs) were developed by a simple and efficient hydrothermal method, which can scavenge H2O2 to protect cells under ambient condition, but generate ·OH under 808 nm irradiation as photodynamic application. This contribution presented a kind of novel CDs with dual-functions, which can potentially regulate ROS under different conditions.

17.
Food Res Int ; 129: 108847, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32036922

RESUMO

The rheological properties and microstructure of dairy gels involve the connectivity between milk fat globules (MFG) and casein micelles that is affected by technological processes such as milk homogenization and heat treatment. The underlying mechanisms require further quantification of the interactions at the nanoscale level to be fully understood and controlled. In this study, we examined the adhesion of homogenized MFG to milk proteins and evaluated the role of ultra-high temperature (UHT) heat treatment and pH. The combination of physico-chemical analysis, rheology and microscopy observations at different scale levels associated to atomic force microscopy (AFM) force spectroscopy were used. AFM experiments performed at the particle scale level showed that adhesion of individual homogenized MFG to milk proteins (1) is increased upon acidification at pH 4.5: 1.4 fold for unheated samples and 3.5 fold for UHT samples, and (2) is enhanced by about 1.7 fold at pH 4.5 after UHT heat treatment of milk, from 176 pN to 296 pN, thanks to highly-reactive heat-denatured whey proteins located at the surface of MFG and caseins. The increased inter-particle adhesion forces accounted for more connected structures and stiffer UHT milk acid gels, compared to unheated-milk gels. Using a multiscale approach, this study showed that heat treatment of milk markedly affected the interactions occurring at the particle's surface level with consequences on the bulk structural and rheological properties of acid gels. Such findings will be useful for manufacturers to modulate the texture of fermented dairy products through the tailoring of heat-induced complexation of proteins and the connectivity of homogenized MFG with the protein network. This work will also contribute in a better understanding of the impact of process-induced changes on the digestibility and metabolic fate of proteins and lipids.


Assuntos
Glicolipídeos/química , Glicoproteínas/química , Calefação , Gotículas Lipídicas/química , Microscopia de Força Atômica/métodos , Análise Espectral/métodos , Proteínas do Soro do Leite/química , Animais , Bovinos , Análise de Alimentos , Manipulação de Alimentos , Temperatura Alta , Concentração de Íons de Hidrogênio
18.
Polymers (Basel) ; 11(11)2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31652961

RESUMO

Developing cheap, clean and atomic-efficient synthetic methodologies for conjugated polymers are always critical for the field of organic electronics. Herein, classic Ullmann coupling polymerization is developed to synthesize a series of Acceptor-Acceptor (A-A) type homopolymers with microwave-assistance, which are supported by nuclear magnetic resonance (NMR), matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF), elemental analysis (EA) and gel permeation chromatography (GPC). The physicochemical properties of these polymers are studied by UV-vis spectroscopy, cyclic voltammetry (CV), thermal gravimetric analysis (TGA), and density functional theory (DFT) calculation. Furthermore, these A-A homopolymers are used as acceptors for all-polymer solar cells (All-PSCs), affording a promising efficiency of 3.08%, which is the highest value for A-A-homopolymer-based organic solar cells.

19.
ACS Appl Mater Interfaces ; 11(19): 17884-17893, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30998309

RESUMO

Semiconducting polymer (SP) nanoparticles (NPs) have recently emerged as one of the most promising agents for photoacoustic imaging (PAI)-guided photothermal/photodynamic therapy (PTT/PDT). Herein, a triplet tellurophene-based SP (PNDI-2T) was synthesized with efficient tin-free direct heteroarylation polycondensation. The PNDI-2T NPs display remarkable near-infrared absorption and low cytotoxicity. In addition, PNDI-2T NPs can generate abundant reactive oxygen species (ROS) since tellurophene facilitates the intersystem crossing to generate triplet excited states. Remarkably, PNDI-2T NPs present a high photothermal conversion efficiency (η = 45%) and a high ROS yield (ΦΔ = 38.7%) under 808 nm laser irradiation. Furthermore, we showed that PNDI-2T NPs could be excellent PAI-guided PTT/PDT agents for cancer theranostics. This study provides a new route to developing highly efficient and low cytotoxic agents for PAI-guided PTT/PDT.


Assuntos
Nanopartículas/química , Fotoquimioterapia , Polímeros/farmacologia , Nanomedicina Teranóstica , Proliferação de Células/efeitos dos fármacos , Células HeLa , Humanos , Técnicas Fotoacústicas , Polímeros/química , Espécies Reativas de Oxigênio/química , Semicondutores , Telúrio/química
20.
Colloids Surf B Biointerfaces ; 182: 110363, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31344611

RESUMO

The surface of milk fat globules consists of a biological membrane rich in polar lipids and glycoproteins. However, high shear stress applied upon homogenization disrupts the membrane and leads to the adsorption of casein micelles, as the major protein fraction of milk. These changes in the interface properties could affect the interactions between native or homogenized milk fat globules and the surrounding protein matrix, at neutral pH and upon acidification. In this study, macroscale rheometry, microscopic observations, nanoscale AFM-based force spectroscopy and physico-chemical analysis were combined to examine the interfacial composition and structure of milk fat globules and to evaluate their interactions with casein micelles. We showed that the surface properties of milk fat globules (biological membrane vs. caseins) and pH govern their interactions with casein micelles. The adhesion between individual fat globules and casein micelles was higher upon homogenization, especially at acid pH where the work of adhesion increased from 3.3 x 10-18 to 14 x 10-18 J for native and homogenized fat globules, respectively. Consequently, casein-coated homogenized fat globules yield stiffer milk acid gels. These findings cast light on the importance of colloidal particle's surface properties and pH on their connectivity with the surrounding matrix, which modulates the bulk microstructure and rheological properties with potential functional consequences, such as milk lipid digestion.


Assuntos
Caseínas/química , Glicolipídeos/química , Glicoproteínas/química , Leite/química , Animais , Géis , Concentração de Íons de Hidrogênio , Gotículas Lipídicas , Micelas , Microscopia de Força Atômica , Tamanho da Partícula , Ligação Proteica , Reologia , Propriedades de Superfície
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