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1.
PLoS One ; 15(8): e0237971, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32833977

RESUMO

Satellite-based methods are proposed for the estimation of clear day average hourly illuminance from satellite data under local climate conditions. First, aerosol optical depth (AOD) data collected using a ground-based sun photometer were used to calibrate the satellite remote sensing AOD data. Next, we screened for the factors affecting the illuminance of clear sky and detected three important factors, namely the sine of the solar altitude angle, aerosol optical thickness, and atmospheric precise water content. Finally, based on the AOD data of satellite remote sensing, combined with the local illumination data and meteorological data, a clear sky average hourly illumination model in Chongqing was established via the regression method. There was good agreement between the calculated and the measured values of clear day average hourly illuminance, with a root mean square difference and mean bias difference of 22% and -0.05%, respectively. The model was used to map clear day annual, quarterly, and monthly average hourly illuminance. The maps show the clear day annual, seasonal, and monthly variations of average hourly illuminance in Chongqing.


Assuntos
Poluição do Ar , Monitoramento Ambiental/estatística & dados numéricos , Luz , Fenômenos Ópticos , China , Cidades , Modelos Estatísticos , Estações do Ano , Astronave
2.
Int J Nanomedicine ; 15: 4959-4967, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764929

RESUMO

Background: Particle-based drug delivery systems (DDSs) have a demonstrated value for drug discovery and development. However, some problems remain to be solved, such as limited stimuli, visual-monitoring. Aim: To develop an intelligent multicolor DDSs with both near-infrared (NIR) controlled release and macroscopic color changes. Materials and Methods: Microparticles comprising GO/pNIPAM/PEGDA composite hydrogel inverse opal scaffolds, with dextran and calcium alginate hydrogel were synthesized using SCCBs as the template. The morphology of microparticle was observed under scanning electron microscopy, and FITC-dextran-derived green fluorescence images were determined using a confocal laser scanning microscope. During the drug release, FITC-dextran-derived green fluorescence images were captured using fluorescent inverted microscope. The relationship between the power of NIR and the drug release rate was obtained using the change in optical density (OD) values. Finally, the amount of drug released could be estimated quantitatively used the structural color or the reflection peak position. Results: A fixed concentration 8% (v/v) of PEGDA and 4mg/mL of GO was chosen as the optimal concentration based on the balance between appropriate volume shrinkage and structure color. The FITC-dextran was uniformly encapsulated in the particles by using 0.2 wt% sodium alginate. The microcarriers shrank because of the photothermal response and the intrinsic fluorescence intensity of FITC-dextran in the microparticles gradually decreased at the same time, indicating drug release. With an increasing duration of NIR irradiation, the microparticles gradually shrank, the reflection peak shifted toward blue and the structural color changed from red to orange, yellow, green, cyan, and blue successively. The drug release quantity can be predicted by the structural color of microparticles. Conclusion: The multicolor microparticles have great potential in drug delivery systems because of its vivid reporting color, excellent photothermal effect, and the good stimuli responsivity.


Assuntos
Portadores de Fármacos/química , Microesferas , Resinas Acrílicas/química , Alginatos/química , Cor , Dextranos/química , Liberação Controlada de Fármacos , Fluoresceína-5-Isotiocianato/análogos & derivados , Fluoresceína-5-Isotiocianato/química , Hidrogéis/química , Fenômenos Ópticos , Polietilenoglicóis/química
3.
Opt Express ; 28(12): 18224-18240, 2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32680023

RESUMO

Recently the acquisition of the time-resolved reflection matrix was demonstrated based on spectral domain optical coherence tomography. In principle, the matrix describes the linear dependence of the OCT signal received from different depths on the field which is incident to the scattering sample. Knowledge of the matrix, hence, enables beam shaping to selectively enhance the received signal, for example to increase the penetration depth when imaging turbid media. We investigate the impact of image artefacts on the approach. Phase conjugation is shown to enhance the OCT signal, but not autocorrelation and mirror artefacts. Imaging applications are demonstrated indicating the potential for future in-vivo studies on biotissues.


Assuntos
Algoritmos , Artefatos , Luz , Espalhamento de Radiação , Tomografia de Coerência Óptica/métodos , Interferometria/métodos , Fenômenos Ópticos , Fatores de Tempo , Tomografia de Coerência Óptica/instrumentação
4.
Food Chem ; 332: 127150, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32659696

RESUMO

We report an optical biosensor using imine, 5-((anthrcene-9-ylmethylene) amino)-2,3dihydrophthalazine) 1-4-dione (ADD) for direct detection of ascorbic acid (AA) via FRET quenched. The ADD was successfully prepared by using simple ultra - sonication method, which was characterized by various spectroscopic techniques. The fluorescence intensity of ADD probe was drastically quenched in presence of AA, and shown excellent selectivity towards the detection of AA in presence of possible biological active interferences. A wide linear range from 0.25 to 190 µM was achieved towards the detection of AA with a LOD of 10 nM. The occurrence of FRET mechanism is due to intermolecular hydrogen bonding between ADD and AA, which was confirmed by Density Functional Theory calculations. Moreover, the biosensor was successfully applied for the detection of AA in real samples such as fruits and vegetables to demonstrate the practicability. In addition, the developed biosensor could be a simple and economically cheap platform for the detection of AA in food samples.


Assuntos
Ácido Ascórbico/análise , Técnicas Biossensoriais/métodos , Frutas/química , Luminol/análogos & derivados , Fenômenos Ópticos , Sonicação , Verduras/química , Técnicas de Química Sintética , Limite de Detecção , Luminol/síntese química , Luminol/química
5.
Proc Natl Acad Sci U S A ; 117(31): 18310-18316, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32675247

RESUMO

Bionic electronic skin (E-skin) that could convert external physical or mechanical stimuli into output signals has a wide range of applications including wearable devices, artificial prostheses, software robots, etc. Here, we present a chameleon-inspired multifunctional E-skin based on hydroxypropyl cellulose (HPC), Poly(Acrylamide-co-Acrylic acid) (PACA), and carbon nanotubes (CNTs) composited liquid-crystal hydrogel. We found that the HPC could still form cholesteric liquid-crystal photonic structures with the CNTs additive for enhancing their color saturation and PACA polymerization for locating their assembled periodic structures. As the composite hydrogel containing HPC elements and the PACA scaffold responds to different stimuli, such as temperature variations, mechanical pressure, and tension, it could correspondingly change its volume or internal nanostructure and report these as visible color switches. In addition, due to the additive of CNTs, the composite hydrogel could also output these stimuli as electrical resistance signals. Thus, the hydrogel E-skins had the ability of quantitatively feeding back external stimuli through electrical resistance as well as visually mapping the stimulating sites by color variation. This dual-signal sensing provides the ability of visible-user interaction as well as antiinterference, endowing the multifunctional E-skin with great application prospects.


Assuntos
Celulose/química , Condutividade Elétrica , Hidrogéis/química , Cristais Líquidos , Dispositivos Eletrônicos Vestíveis , Cor , Fenômenos Ópticos
6.
J Breath Res ; 14(4): 047102, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32531773

RESUMO

The fraction of exhaled nitric oxide (FENO) is an important biomarker for the diagnosis and management of asthma and other pulmonary diseases associated with airway inflammation. In this study we report on a novel method for accurate, highly time-resolved, real time detection of FENO at the mouth. The experimental arrangement is based on a combination of optical sensors for the determination of the temporal profile of exhaled NO and CO2 concentrations. Breath CO2 and exhalation flow are measured at the mouth using diode laser absorption spectroscopy (at 2 µm) and differential pressure sensing, respectively. NO is determined in a sidestream configuration using a quantum cascade laser based, cavity-enhanced absorption cell (at 5.2 µm) which simultaneously measures sidestream CO2. The at-mouth and sidestream CO2 measurements are used to enable the deconvolution of the sidestream NO measurement back to the at-mouth location. All measurements have a time resolution of 0.1 s, limited by the requirement of a reasonable limit of detection for the NO measurement, which on this timescale is 4.7 ppb (2 σ). Using this methodology, NO expirograms (FENOgrams) were measured and compared for eight healthy volunteers. The FENOgrams appear to differ qualitatively between individuals and the hope is that the dynamic information encoded in these FENOgrams will provide valuable additional insight into the location of the inflammation in the airways and potentially predict a response to therapy. A validation of the measurements at low-time resolution is provided by checking that results from previous studies that used a two-compartment model of NO production can be reproduced using our technology.


Assuntos
Testes Respiratórios/métodos , Fenômenos Ópticos , Análise Espectral/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
7.
J Vis Exp ; (159)2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32510507

RESUMO

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has been challenged. Here, we fabricate iron oxide nanoparticle shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform. Iron oxide nanoparticles serve as both magnetic and photothermal agents. Once intravenously injected, NSMs can be magnetically guided to the tumor site. Ultrasound triggers the release of iron oxide nanoparticles, facilitating the penetration of nanoparticles deep into the tumor due to the cavitation effect of microbubbles. Thereafter, magnetic hyperthermia and photothermal therapy can be performed on the tumor for combinational cancer therapy, a solution for cancer resistance due to the tumor heterogeneity. In this protocol, the synthesis and characterization of NSMs including structural, chemical, magnetic and acoustic properties were performed. In addition, the anti-cancer efficacy by thermal therapy was investigated using in vitro cell cultures. The proposed delivery strategy and combination therapy holds great promise in cancer treatment to improve both delivery and anticancer efficacies.


Assuntos
Acústica , Hipertermia Induzida , Fenômenos Magnéticos , Microbolhas/uso terapêutico , Neoplasias/terapia , Fenômenos Ópticos , Fototerapia/métodos , Terapia Combinada , Sistemas de Liberação de Medicamentos , Humanos , Temperatura
8.
Int J Nanomedicine ; 15: 3597-3603, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547016

RESUMO

Background: Transparent thin-film transistors (TFTs) have received a great deal of attention for medical sensors, OLED and medical display applications. Moreover, ultrathin nanomaterial layers are favored due to their more compact design architectures. Methods: Here, transparent TFTs are proposed and were investigated under different stress conditions such as temperature and biases. Results: Key electrical characteristics of the sensors, such as threshold voltage changes, illustrate their linear dependence on temperature with a suitable recovery, suggesting the potential of the devices to serve as medical temperature sensors. The temperature conditions changed in the range of 28°C to 40°C, which is within the standard human temperature testing range. The thickness of the indium-gallium-zinc oxide semiconductor layer was as thin as only 5-6 nm, deposited by mature radio-frequency sputtering which also showed good repeatability. Optimal bending durability caused by mechanical deformation was demonstrated via suitable electrical properties after up to 600 bending cycles, and by testing the flexible device at a different bending radii ranging from 48 mm to 18 mm. Conclusion: In summary, this study suggests that the present transparent nano TFTs are promising candidates for medical sensors, OLED and displays which require transparency and stability.


Assuntos
Nanoestruturas/química , Nanotecnologia/métodos , Fenômenos Ópticos , Transistores Eletrônicos , Reprodutibilidade dos Testes , Temperatura
9.
PLoS One ; 15(5): e0232546, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32365135

RESUMO

PURPOSE: To evaluate and compare the effect of misalignment and tilt on the optical performance of different aspheric intraocular lens (IOL) designs. METHODS: Three aspheric IOLs with a different quantity of spherical aberration (SA) have been designed and the effect of IOL misalignment and tilt on the imaging quality of an eye model has been numerically assessed using a commercial optical design software. The prototypes have been manufactured by lathe turning and tested in vitro using the same optical bench (PMTF, Lambda-X) that complies with International Organization for Standardization standard 11979-2 requirements. Image quality was evaluated from the modulation transfer functions (MTFs), through-focus modulation transfer functions (TF-MTFs), root mean square (RMS) values of defocus, astigmatism and coma, and images of the United States Air Force (USAF) target were taken. A comparison with the optical performance of spherical IOLs has also been performed. RESULTS: Intraocular lens misalignment and tilt increased wavefront aberrations; the effect of misalignment on root mean square (RMS) astigmatism and coma was positively correlated with the spherical aberration of the IOL. Aberration-free IOLs showed the highest MTF for all misalignment values and for IOLs with negative SA correction the MTF decays below 0.43 when they are decentered 0.50 mm. CONCLUSIONS: Aspherical IOLs are more sensitive than spherical IOLs to misalignment or tilt, depending on their SA correction. The optical degradation caused by IOL misalignment had a greater effect on IOL designs with a higher amount of negative spherical aberration. In contrast, the effect of tilt on the optical performance was less sensitive to the IOL design.


Assuntos
Lentes Intraoculares , Astigmatismo/fisiopatologia , Astigmatismo/cirurgia , Simulação por Computador , Humanos , Técnicas In Vitro , Implante de Lente Intraocular , Lentes Intraoculares/normas , Lentes Intraoculares/estatística & dados numéricos , Modelos Biológicos , Fenômenos Ópticos , Desenho de Prótese , Pseudofacia/fisiopatologia , Acuidade Visual
10.
PLoS One ; 15(5): e0232982, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32407381

RESUMO

A photonic crystal fiber (PCF) structure with a ring-core and 5 well-ordered semiellipse air-holes has been creatively proposed. Through a comparison between the structures with a high refractive index (RI) ring-core and the structure without, it conclude that a PCF with a high RI ring-core can work better. Schott SF57 was elected as the substrate material of ring-core. This paper compares the effects of long-axis and short-axis changes on the PCF and selects the optimal solution. Especially TE0,1 mode's dispersion is maintained between 0 and 3 ps / (nm · km) ranging from 1.45 µm to 1.65 µm. This property can be used to generate a supercontinuum with 200 µm long zero dispersion wavelength (ZDM). In addition, Δneff reaches up to 10-3, which enables the near -degeneracy of the eigenmodes to be almost neglected. The proposed PCF structure will have great application value in the field of optical communications.


Assuntos
Fibras Ópticas , Simulação por Computador , Desenho de Equipamento , Tecnologia de Fibra Óptica/estatística & dados numéricos , Fibras Ópticas/estatística & dados numéricos , Fenômenos Ópticos , Refratometria/estatística & dados numéricos
11.
PLoS One ; 15(5): e0234066, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470032

RESUMO

The aim of our study was to quantitatively evaluate the optical properties of photochromic lenses available on the market under cold and warm temperatures corresponding to the winter and summer seasons. The transmittance of 12 photochromic lenses from five manufacturers was measured using an UV/VIS spectrophotometer at cold (6 ± 2°C) and at warm (21 ± 2°C) temperatures. Transmittances were recorded from 380 to 780 nm and at the wavelength with maximum absorbance, which was calculated from the transmittance. The characteristics of the lenses were evaluated by examining changes in the optical properties at colorless and colored states and in the fading rate depending on temperature. The wavelength with maximum absorbance for photochromic lenses at the cold temperature showed a shorter shift than that at the warm temperature. The photochromic properties at the cold temperature were 11.5% lower for transmittance, 1.4 times higher for the change in optical density, and 1.2 times higher for the change in transmittance in the colored and colorless states, optical blocking % ratio, and change in luminous transmittance as compared to those at the warm temperature in the colored state. The fading rates based on the half-life time at the cold temperature were from 2.7 to 5.4 times lower than those at the warm temperature. The fading time until 80% transmittance was 6.4 times longer at the cold as compared to that at the warm temperature. There were significant differences in the optical properties of the photochromic lenses in terms of an absorbance at a shorter wavelength, a lower transmittance, a higher optical density, optical blocking % ratio, and luminous transmittance at the cold as compared to the warm temperature. Hence, it is necessary to provide consumers with information on photochromic optical properties, including the transmittance in colored and colorless states, and the fading rates at temperatures corresponding to the summer and winter seasons for each product.


Assuntos
Lentes , Fenômenos Ópticos , Temperatura , Meia-Vida , Cinética , Fatores de Tempo
12.
J Chromatogr A ; 1622: 461173, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32450987

RESUMO

Poly(diphenylacetylene) having optically active anilide pendants (poly-1) were synthesized by the condensation reaction of an optically active carboxylic acid with a key precursor polymer containing amino (-NH2) groups, which was prepared by the polymerization of a phthalimide-protected diphenylacetylene monomer using WCl6-Ph4Sn as a catalyst, followed by phthalimide deprotection in the resulting polymer using hydrazine monohydrate. Poly-1 formed a preferred-handed helical conformation (h-poly-1) upon thermal annealing in DMF because of chirality of the pendant group. Poly-1 and h-poly-1 showed different chiral recognition abilities from the analogous poly(diphenylacetylene)s, having the corresponding optically active amide pendants, as chiral stationary phases (CSPs) for high-performance liquid chromatography. The resolution results with the h-poly-1-based CSP were much better than those with the poly-1-based CSP owing to the preferred-handed macromolecular helicity. Among the tested racemates, the h-poly-1-based CSP exhibited superior chiral recognition ability, especially toward binaphthyl compounds and chiral metal complexes.


Assuntos
Acetileno/análogos & derivados , Anilidas/síntese química , Cromatografia Líquida de Alta Pressão/métodos , Fenômenos Ópticos , Acetileno/química , Anilidas/química , Polimerização , Polímeros/síntese química , Polímeros/química , Estereoisomerismo
13.
J Vis Exp ; (158)2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32364541

RESUMO

In this work, we describe a protocol for a novel application of hyperspectral imaging (HSI) in the analysis of luminescent lanthanide (Ln3+)-based molecular single crystals. As representative example, we chose a single crystal of the heterodinuclear Ln-based complex [TbEu(bpm)(tfaa)6] (bpm=2,2'-bipyrimidine, tfaa- =1,1,1-trifluoroacetylacetonate) exhibiting bright visible emission under UV excitation. HSI is an emerging technique that combines 2-dimensional spatial imaging of a luminescent structure with spectral information from each pixel of the obtained image. Specifically, HSI on single crystals of the [Tb-Eu] complex provided local spectral information unveiling variation of the luminescence intensity at different points along the studied crystals. These changes were attributed to the optical anisotropy present in the crystal, which results from the different molecular packing of Ln3+ ions in each one of the directions of the crystal structure. The HSI herein described is an example of the suitability of such technique for spectro-spatial investigations of molecular materials. Yet, importantly, this protocol can be easily extended for other types of luminescent materials (such as micron-sized molecular crystals, inorganic microparticles, nanoparticles in biological tissues, or labelled cells, among others), opening many possibilities for deeper investigation of structure-property relationships. Ultimately, such investigations will provide knowledge to be leveraged into the engineering of advanced materials for a wide range of applications from bioimaging to technological applications, such as waveguides or optoelectronic devices.


Assuntos
Elementos da Série dos Lantanídeos/química , Imagem Óptica , Fenômenos Ópticos , Anisotropia , Luminescência
14.
Langmuir ; 36(16): 4405-4415, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32243164

RESUMO

This paper presents sols of uncoated and citric acid-coated Fe3O4 nanoparticles obtained by a combination of coprecipitation and sonochemistry methods. A stable concentrated CA-Fe3O4 sol synthesized by a combination of coprecipitation with an inconvenient Fe2+/Fe3+ ratio, modification with citric acid and US treatment was obtained for the first time. A comparative analysis of the composition and morphology of nanoparticles was performed. The sols are oppositely charged and behave as a typical ferrofluid. The citric acid-modified sol is aggregatively stable over wider ranges of pH and electrolyte concentration, but it becomes less stable with the temperature increase. DLVO calculations showed that steric repulsion forces are a vital factor contributing to increased aggregative stability in a modified Fe3O4 sol. The experiments have revealed the magneto-optical effect in a modified Fe3O4 sol with an electrolyte concentration of 0.025-0.075 M caused by a high potential barrier and a deep secondary minimum in pairwise interaction curves. The "pK spectroscopy" mathematical model to describe the potentiometric curves of synthesized magnetite sols was used for the first time. According to potentiometric titration, the ions of the electrolyte practically do not contribute to formation of a surface charge in modified Fe3O4 with a change in pH due to blocking the magnetite surface by citric acid molecules. Drosophila melanogaster was used as a model to show that Fe3O4 in chronic exposure has a low toxic effect.


Assuntos
Drosophila melanogaster/efeitos dos fármacos , Longevidade/efeitos dos fármacos , Nanopartículas de Magnetita/química , Soluções/química , Animais , Ácido Cítrico/química , Ácido Cítrico/toxicidade , Feminino , Fenômenos Magnéticos , Nanopartículas de Magnetita/toxicidade , Masculino , Fenômenos Ópticos , Tamanho da Partícula , Soluções/toxicidade
15.
Opt Lett ; 45(6): 1293-1296, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32163948

RESUMO

Spatiotemporal optical coherence (STOC) imaging is a new technique for suppressing coherent cross talk noise in Fourier-domain full-field optical coherence tomography (FD-FF-OCT). In STOC imaging, the time-varying inhomogeneous phase masks modulate the incident light to alter the interferometric signal. Resulting interference images are then processed as in standard FD-FF-OCT and averaged incoherently or coherently to produce cross-talk-free volumetric optical coherence tomography (OCT) images of the sample. Here, we show that coherent averaging is suitable when phase modulation is performed for both interferometer arms simultaneously. We explain the advantages of coherent over incoherent averaging. Specifically, we show that modulated signal, after coherent averaging, preserves lateral phase stability, enabling computational phase correction to compensate for geometrical aberrations. Ultimately, we employ it to correct for aberrations present in the image of the photoreceptor layer of the human retina that reveals otherwise invisible photoreceptor mosaics.


Assuntos
Tomografia de Coerência Óptica/métodos , Adulto , Análise de Fourier , Humanos , Imageamento Tridimensional/métodos , Imageamento Tridimensional/estatística & dados numéricos , Interferometria/métodos , Interferometria/estatística & dados numéricos , Fenômenos Ópticos , Células Fotorreceptoras de Vertebrados/citologia , Retina/anatomia & histologia , Retina/diagnóstico por imagem , Razão Sinal-Ruído , Análise Espaço-Temporal , Tomografia de Coerência Óptica/estatística & dados numéricos
16.
Opt Lett ; 45(6): 1379-1382, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32163975

RESUMO

We embed large-scale, plasmonic metasurfaces into off-the-shelf rigid gas permeable contact lenses and study their ability to serve as visual aids for color vision deficiency. In this study, we specifically address deuteranomaly, which is the most common class of color vision deficiency. This condition is caused by a redshift of the medium-type cone photoreceptor and leads to ambiguity in the color perception of red and green and their combinations. The effect of the metasurface-based contact lenses on the color perception was simulated using Commission Internationale de l'Eclairage (CIE) color spaces and conventional models of the human color-sensitive photoreceptors. Comparison between normal color vision and uncorrected and corrected deuteranomaly by the proposed element demonstrates the ability offered by the nanostructured contact lens to shift back incorrectly perceived pigments closer to the original pigments. The maximal improvement in the color perception error before and after the proposed correction for deuteranomaly is up to a factor of $\sim{10}$∼10. In addition, an Ishihara-based color test was also simulated, showing the contrast restoration achieved by the element, for deuteranomaly conditions.


Assuntos
Defeitos da Visão Cromática/reabilitação , Lentes de Contato , Auxiliares Sensoriais , Materiais Revestidos Biocompatíveis , Percepção de Cores , Testes de Percepção de Cores , Defeitos da Visão Cromática/fisiopatologia , Simulação por Computador , Desenho de Equipamento , Humanos , Nanoestruturas , Dispositivos Ópticos , Fenômenos Ópticos , Análise Espectral , Propriedades de Superfície
17.
Mikrochim Acta ; 187(4): 208, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-32152752

RESUMO

A nanocurcumin (NCur)-VO2+ ensemble-based optical nanoprobe is proposed for monitoring of human serum albumin (HSA) and transferrin (TF) in biofluids of serum and urine. The determination strategy of HSA and TF is based on the decrease of the absorbance/color intensity of NCur in the presence of VO2+ due to the formation of NCur-VO2+ ensemble. This leads to aggregation of the NCur and the color change of solution from orange to pale pink. Upon addition of HSA or TF, release of VO2+ from NCur-VO2+ ensemble occurs due to their stronger binding affinities to VO2+ in competition with the NCur. This leads to deaggregation of the NCur and recovery of the decreased absorption/color intensity within a defined time range. The absorption changes at λ = 455 and the color of NCur solution can be monitored spectrophotometrically or visually by a smartphone camera, respectively. Under optimal conditions, the analytical signals increase linearly in the ranges 50-200 nM (LOD = 11 nM) and 20-140 nM (LOD = 8 nM) for HSA and TF, respectively. The difference in the different affinities between the HSA and the TF for binding to VO2+ produces the unique time profiles of each protein. Therefore, the simultaneous determination of HSA and TF is provided by using the least-square support-vector machine (LS-SVM) model. The good recoveries and small errors of predicted values suggest that the nanoprobe is capable to resolve binary mixtures of HSA and TF. The method was applied to the simultaneous determination of HSA and TF in serum and urine samples. Graphical abstract.


Assuntos
Líquidos Corporais/química , Nanopartículas/química , Albumina Sérica Humana/análise , Transferrina/análise , Curcumina/química , Humanos , Modelos Moleculares , Fenômenos Ópticos , Software , Espectrofotometria , Ultrassom , Vanadatos/química
18.
Mikrochim Acta ; 187(4): 230, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170435

RESUMO

An interferometric reflectance spectroscopy-based biosensor for the determination of cathepsin B (Cat B) as a cancer-related enzyme has been fabricated. For this purpose, the nanoporous anodic alumina (NAA) was fabricated electrochemically. The NAA was then modified with the amino-silane coupling agent. After that, human serum albumin (HSA) was immobilized into the NAA pores by using glutaraldehyde as a cross-linking agent. Subsequently, the carboxylic group of HSA was activated with N-ethyl-N'-(3-(dimethylamino)propyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to attach to thionine (TH) as a photoprobe to fabricate the labeled HSA (HSA-TH). HSA-TH plays a significant role in this sensor to determine cathepsin B as a model analyte for the development of the interferometric reflectance spectroscopy-based biosensor for the measurement of protease. The attached TH adsorbed the illuminated white light on NAA modified with HSA-TH. Therefore, the intensity of the reflected light to the charge-coupled device (CCD) detector decreased in the wavelength range 450-1050 nm. In the presence of Cat B, HAS-TH cleaved into short peptide fragments and washed away by flow cell system. Since TH was removed from NAA, the intensity of the reflected light increased. The peak area has a logarithmic relationship with the concentration of Cat B in the range 0.5 to 64.0 nM. The limit of detection of the biosensor sensor was 0.08 nM. The optical sensor was used for the determination of Cat B in a human serum sample. Graphical abstract Schematic presentation of biosensor for the determination of the cathepsin B which is based on nanoporous anodic alumina modified with HSA-thionine. The principle response of the optical biosensor is based on detecting changes in the intensity of the reflected light after cleaving the immobilized HSA-thionine by cathepsin B into short peptide fragments.


Assuntos
Óxido de Alumínio/química , Técnicas Biossensoriais , Catepsina B/análise , Técnicas Eletroquímicas , Fenotiazinas/química , Albumina Sérica Humana/química , Catepsina B/metabolismo , Eletrodos , Humanos , Fenômenos Ópticos , Tamanho da Partícula , Porosidade , Propriedades de Superfície
19.
Mikrochim Acta ; 187(4): 234, 2020 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-32180011

RESUMO

This review (with 145 refs.) summarizes the progress that has been made in the use of zeolitic imidazolate frameworks in chemical sensing and biosensing. Zeolitic imidazolate frameworks (ZIFs) are a type of porous material with zeolite topological structure that combine the advantages of zeolite and traditional metal-organic frameworks. Owing to the structural flexibility of ZIFs, their pore sizes and surface functionalization can be reasonably designed. Following an introduction into the field of metal-organic frameworks and the zeolitic imidazolate framework (ZIF) subclass, a first large section covers the various kinds and properties of ZIFs. The next large section covers electrochemical sensors and assays (with subsections on methods for gases, electrochemiluminescence, electrochemical biomolecules). This is followed by main sections on ZIF-based colorimetric and luminescent sensors, with subsections on sensors for metal ions and anions, for gases, and for organic biomolecules. The last section covers SERS-based assays. Several tables are presented that give an overview on the wealth of methods and materials. A concluding section summarizes the current status, addresses current challenges, and gives an outlook on potential future trends. Graphical abstract In recent years, ZIFs and their composites have been widely used as probes in chemical sensing, and these probes have shown great advantages over other materials. This review describes the current progress on ZIFs toward electrochemical, luminescence, colorimetric, and SERS-based sensing applications, highlighting the different strategies for designing ZIFs and their composites and potential challenges in this field.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Imidazóis/química , Estruturas Metalorgânicas/química , Zeolitas/química , Fenômenos Ópticos
20.
Sci Adv ; 6(8): eaay5064, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32128406

RESUMO

PROTACs (PROteolysis TArgeting Chimeras) are bifunctional molecules that target proteins for ubiquitylation by an E3 ligase complex and subsequent degradation by the proteasome. They have emerged as powerful tools to control the levels of specific cellular proteins. We now introduce photoswitchable PROTACs that can be activated with the spatiotemporal precision that light provides. These trifunctional molecules, which we named PHOTACs (PHOtochemically TArgeting Chimeras), consist of a ligand for an E3 ligase, a photoswitch, and a ligand for a protein of interest. We demonstrate this concept by using PHOTACs that target either BET family proteins (BRD2,3,4) or FKBP12. Our lead compounds display little or no activity in the dark but can be reversibly activated with different wavelengths of light. Our modular approach provides a method for the optical control of protein levels with photopharmacology and could lead to new types of precision therapeutics that avoid undesired systemic toxicity.


Assuntos
Fenômenos Ópticos , Proteólise , Linhagem Celular Tumoral , Humanos , Luz , Proteólise/efeitos da radiação , Proteína 1A de Ligação a Tacrolimo/metabolismo
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