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1.
Adv Exp Med Biol ; 1232: 375-381, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893434

RESUMO

The value of optical redox imaging (ORI) of cells/tissues based on the intrinsic fluorescences of NADH (nicotinamide adenine dinucleotide) and oxidized flavoproteins (containing flavin adenine dinucleotide, i.e., FAD) has been demonstrated for potential biomedical applications including diagnosis, prognosis, and determining treatment response. However, the Chance redox scanner (a 3D cryogenic tissue imager) is limited by spatial resolution (~50 µm), and tissue ORI using fluorescence microscopy (single or multi-photon) is limited by the light penetration depth. Furthermore, viable or snap-frozen tissues are usually required. In this project, we aimed to study whether ORI may be achieved for unstained fixed tissue using a state-of-the-art modern Serial Two-Photon (STP) Tomography scanner that can rapidly acquire multi-plane images at micron resolution. Tissue specimens of mouse muscle, liver, and tumor xenografts were harvested and fixed in 4% paraformaldehyde (PFA) for 24 h. Tissue blocks were scanned by STP Tomography under room temperature to acquire the autofluorescence signals (NADH channel: excitation 750 nm, blue emission filter; FAD channel: excitation 860 nm, green emission filter). We observed remarkable signals with significant intra-tissue heterogeneity in images of NADH, FAD and redox ratio (FAD/(NADH+FAD)), which are worthy of further investigation for extracting biological information.


Assuntos
Tecnologia Biomédica , NAD , Imagem Óptica , Animais , Tecnologia Biomédica/instrumentação , Tecnologia Biomédica/métodos , Estudos de Viabilidade , Flavina-Adenina Dinucleotídeo , Xenoenxertos/diagnóstico por imagem , Camundongos , Oxirredução , Fótons
2.
Chem Commun (Camb) ; 56(9): 1349-1352, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31904042

RESUMO

Herein, a novel two-photon ratiometric fluorescence assay was proposed for monitoring endogenous steroid sulfatase (STS) activity, which could be applied for the ratiometric imaging of STS activity in the endoplasmic reticulum of living cells and tissues and also could be used to distinguish estrogen-dependent tumor cells from other types of cells.


Assuntos
Corantes Fluorescentes/química , Naftalimidas/química , Esteril-Sulfatase/análise , Animais , Linhagem Celular Tumoral , Retículo Endoplasmático/metabolismo , Corantes Fluorescentes/metabolismo , Corantes Fluorescentes/toxicidade , Células HEK293 , Humanos , Limite de Detecção , Microscopia de Fluorescência/métodos , Simulação de Acoplamento Molecular , Naftalimidas/metabolismo , Naftalimidas/toxicidade , Fótons , Ligação Proteica , Esteril-Sulfatase/metabolismo
3.
Phys Chem Chem Phys ; 22(5): 2999-3007, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31957771

RESUMO

Infrared multiple photon dissociation (IRMPD) spectroscopy has been used to probe the structures of the three protonated base-pair mismatches containing 9-ethylguanine (9eG) in the gas phase. Computational chemistry has been used to determine the relative energies and compute the infrared spectra of these complexes. By comparing the IRMPD spectra with the computed spectra, in all cases, it was possible to deduce that what was observed experimentally were the lowest energy computed structures. The protonated complex between 9eG and 1-methylthymine (1mT) is protonated at N7 of 9eG-the most basic site of all three bases in this study-and bound in a Hoogsteen type structure with two hydrogen bonds. The experimental IRMPD spectrum for the protonated complex between 9eG and 9-methyladenine (9mA) is described as arising from a combination of the two lowest energy structures, both which are protonated at N1 of adenine and each containing two hydrogen bonds with 9eG being the acceptor of both. The protonated dimer of 9eG is protonated at N7 with an N7-H+-N7 ionic hydrogen bond. It also contains an interaction between a C-H of protonated guanine and the O6 carbonyl of neutral guanine which is manifested in a slight red shift of that carbonyl stretch. The protonated 9eG/9mA structures have been previously identified by X-ray crystallography in RNA and are contained within the protein database.


Assuntos
Gases/química , Guanina/análogos & derivados , Espectrofotometria Infravermelho , Adenina/análogos & derivados , Adenina/química , Adenina/metabolismo , Pareamento Incorreto de Bases , Cristalografia por Raios X , Guanina/química , Guanina/metabolismo , Ligações de Hidrogênio , Modelos Moleculares , Fótons , Timina/análogos & derivados , Timina/química , Timina/metabolismo
4.
Zhongguo Yi Liao Qi Xie Za Zhi ; 43(6): 391-396, 2019 Nov 30.
Artigo em Chinês | MEDLINE | ID: mdl-31854520

RESUMO

Fluorescent Diffuse Optical Tomography (FDOT), as a new imaging technology, can achieve three-dimensional quantitative functional imaging of probe in biological tissues, and has wide application value in biomedicine. Forward model which describes the photon propagation within a biological tissue is a prerequisite for implementing FDOT and determines the performance of FDOT. To further improve the efficiency of FDOT, this paper proposes a new forward model based on the Lattice Boltzmann (LB) method derived from the discretization of radiation transfer equation and applies it to FDOT. The experimental results of numerical simulation and physical phantom show that the LB-based forward model proposed in this paper can increase the imaging speed of FDOT by about 5 times compared with the traditional diffusion equation method, without reducing its imaging quality.


Assuntos
Tomografia Óptica , Difusão , Imagens de Fantasmas , Fótons
7.
Phys Rev Lett ; 123(16): 163901, 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31702361

RESUMO

When the feature size of photonic structures becomes comparable or even smaller than the wavelength of light, the fabrication imperfections inevitably introduce disorder that may eliminate many functionalities of subwavelength photonic devices. Here we suggest a novel concept to achieve a robust band gap which can endure disorder beyond 30% as a result of the transition from photonic crystals to Mie-resonant metamaterials. By utilizing Mie-resonant metamaterials with high refractive index, we demonstrate photonic waveguides and cavities with strong robustness to position disorder, thus providing a novel approach to the band-gap-based nanophotonic devices with new properties and functionalities.


Assuntos
Modelos Teóricos , Óptica e Fotônica/métodos , Fótons
8.
Anal Bioanal Chem ; 411(29): 7737-7745, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31713014

RESUMO

A newly developed molecularly imprinted photonic polymer (MIPP) film, which was prepared by colloidal crystal templating and surface molecular imprinting, was used for selective capture of S-layer protein (SLP) from a complex Lactobacillus acidophilus sample. The colloidal crystal templates were formed by a dipping process followed by chemical binding of the imprinted template SLP molecules. A sandwich structure consisting of two glass slides was formed after the SLP-silica layer had been covered with a poly(methyl methacrylate) glass slide. After polymerization of the SLP-silica layer with the preprepared polymerization solution, hydrofluoric acid and acetic phosphate buffer solutions removed the silica particles and SLP molecules, respectively. The MIPP film obtained exhibited a three-dimensional, highly ordered and interconnected macroporous structure (pore size greater than 200 nm), which is specifically accessible to SLP molecules. The adsorbed SLP molecules were simply and straightforwardly detected by a fiber-optic spectrometer. The redshift of the Bragg diffraction peak of the MIPP film was linearly related to the number of SLP molecules that had been harvested in the film. The detection limit of the SLP-MMIP-fiber-optic spectrometer method for SLP was 1 ng mL-1. The MIPP sensor was successfully applied to detect SLP molecules in a crudely extracted Lactobacillus acidophilus sample. Our results prove the applicability of the SLP-MIPP film for fast and real-time measurement of SLP. Graphical abstract.


Assuntos
Proteínas de Bactérias/análise , Tecnologia de Fibra Óptica , Glicoproteínas de Membrana/análise , Impressão Molecular , Fótons , Polímeros/química , Análise Espectral/instrumentação , Lactobacillus acidophilus/química , Limite de Detecção
9.
Chem Commun (Camb) ; 55(87): 13140-13143, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31617528

RESUMO

In this work, we depleted glutathione (GSH) by releasing SO2 with internal stimulus GSH itself, and also selectively marked the cancer cells followed by release of anticancer drug using another orthogonal stimulus i.e., two-photon (TP) NIR light by a single naphthalene based chromophore (TP absorbance 77 GM and uncaging cross-section 21 GM). We demonstrated the improved therapeutic efficacy of chlorambucil by the stepwise dual stimuli approach and dual surveillance of both the drug uncaging process in real-time using in vitro studies.


Assuntos
Alquilantes/farmacologia , Antineoplásicos Alquilantes/farmacologia , Clorambucila/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Naftalenos/farmacologia , Fótons , Alquilantes/química , Antineoplásicos Alquilantes/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Clorambucila/química , Liberação Controlada de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Glutationa/metabolismo , Humanos , Raios Infravermelhos , Estrutura Molecular , Naftalenos/química , Imagem Óptica , Dióxido de Enxofre/metabolismo
10.
Nihon Hoshasen Gijutsu Gakkai Zasshi ; 75(10): 1135-1140, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31631106

RESUMO

Radiotherapy linear accelerators are calibrated to deliver a specific dose under standard conditions following accepted protocols (for example, JSMP12 protocol). The linear accelerator output is calibrated to deliver 1.0 cGy per 1.0 monitor unit (MU) at the depth of maximum in tissue maximum ratio. Beams of photons or electrons pass through a monitor chamber located in the linear accelerators head, which turns off the beam once the prescribed MU is delivered. The clinical outcome of radiotherapy demands that the linear accelerators output do not deviate from the calibrated level by more than a few percent. The purpose of this study is to characterize and understand the long term behavior of the output, change of flatness and symmetry from megavoltage radiotherapy linear accelerators (TrueBeam, Varian Medical Systems). Output trends of beams from three linear accelerators in two institutions over a period of more than 3 years are reported and analyzed. Output taken once per month the basis of this study. The output is measured using ionization chamber with water phantom. These are calibrated by accredited dosimetry laboratory with Japanese traceability system. When the output variation was bounded ±1%, monitor chamber was re-calibrated. The results show that the output from Linac was constantly upward trend. The output of Linac increased up to 8.0% in 1st year. However, upward trend became plateau slowly after years. Beams of same energies from another Linac are correlated with a correlation coefficient. Symmetry and flatness from one Truebeam stabled within 1%. If these adjustments are artificially removed then there is an increase in output, it is important to check the output of linear accelerator periodically.


Assuntos
Aceleradores de Partículas , Fótons , Elétrons , Imagens de Fantasmas , Radiometria , Dosagem Radioterapêutica
12.
Chem Commun (Camb) ; 55(84): 12667-12670, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31584046

RESUMO

We have synthesized symmetrical carbocyanine dyes in which two 4-quinolinium rings are joined by a pentamethine bridge that is meso-substituted with H or Cl. Irradiation of the halogenated dye at 830 nm produces hydroxyl radicals that generate DNA direct strand breaks. This represents the first reported example of DNA photocleavage upon single photon excitation of a chromophore at wavelengths above 800 nm.


Assuntos
Carbocianinas/química , Clivagem do DNA/efeitos da radiação , DNA/química , Corantes Fluorescentes/química , Quinolinas/química , Antineoplásicos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Humanos , Radical Hidroxila/química , Raios Infravermelhos , Estrutura Molecular , Imagem Óptica , Processos Fotoquímicos , Fótons , Espectrometria de Fluorescência
13.
Nat Commun ; 10(1): 4282, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31537786

RESUMO

Microbial biophotovoltaics (BPV) offers a biological solution for renewable energy production by using photosynthetic microorganisms as light absorbers. Although abiotic engineering approaches, e.g., electrode modification and device optimization, can enhance the electrochemical communication between living cells and electrodes, the power densities of BPV are still low due to the weak exoelectrogenic activity of photosynthetic microorganisms. Here, we develop a BPV based on a D-lactate mediated microbial consortium consisting of photosynthetic cyanobacteria and exoelectrogenic Shewanella. By directing solar energy from photons to D-lactate, then to electricity, this BPV generates a power density of over 150 mW·m-2 in a temporal separation setup. Furthermore, a spatial-temporal separation setup with medium replenishment enables stable operation for over 40 days with an average power density of 135 mW·m-2. These results demonstrate the electron flow constrained microbial consortium can facilitate electron export from photosynthetic cells and achieve an efficient and durable power output.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Eletricidade , Energia Renovável , Shewanella/metabolismo , Synechococcus/metabolismo , Técnicas Eletroquímicas , Ácido Láctico/metabolismo , Fótons , Shewanella/genética , Energia Solar , Synechococcus/genética
14.
Phys Med ; 64: 74-80, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31515038

RESUMO

PURPOSE: The aim of this study was to investigate the response of a nanoDot optically stimulated luminescence dosimeter (OSLD) system in megavoltage photon beams. METHODS: The nanoDot response was compared with the ionization chamber measurements for 4-18-MV photons in a plastic water phantom. The response was also calculated by the Monte Carlo method. In addition, the perturbation correction factor, PQ, in the nanoDot cavity was calculated according to the Burlin's cavity theory. The angular dependence of the nanoDot was evaluated using a spherical phantom. RESULTS: The calculated and measured nanoDot responses at a 10-cm depth and 10 × 10-cm2 field were in agreement within 1% for 4-18-MV. The response increased by 3% at a 20 × 20-cm2 field for the lower energy of 4 MV; however, it was constant within ±1% for 6-18 MV. The response was in a range from 1.0 to 0.99 for mean photon energy of more than 1.0 MeV but it increased with less than the 1.0 MeV. PQ for the nanoDot cavity was approximately constant at 0.96-0.97 for greater than and equal to 10 MV. The angular dependence decreased by 5% and 3% for 6 and 15 MV, respectively. CONCLUSIONS: The nanoDot was energy-independent in megavoltage photon beams.


Assuntos
Nanotecnologia , Dosimetria por Luminescência Estimulada Opticamente , Fótons , Método de Monte Carlo
15.
Opt Express ; 27(18): 24914-24922, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31510372

RESUMO

Reconfigurable/reprogrammable universal silicon photonic circuits represent a paradigm shift in designing photonic devices. However, it is very challenging to perform adaptive arbitrary reconfiguration when the high-dimensional solution of phase distribution cannot be explicitly determined, especially when there are random initial phase errors, which hinder the implementation of novel potential functions in universal circuits. This work presents an arbitrary black-box reconfiguration for universal circuits with random phase errors by a bacteria-foraging algorithm and unlocks a novel function of arbitrary-port-and-arbitrary-bit-resolution reconfigurable 6-bit photonic digital-to-analog conversion. This work offers a general and efficient method to ease multipurpose reconfiguration for universal silicon photonic circuits.


Assuntos
Algoritmos , Conversão Análogo-Digital , Bactérias/metabolismo , Fótons , Silício/química , Interferometria
16.
Analyst ; 144(20): 6089-6097, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31531497

RESUMO

Raman spectroscopy is a powerful analytical tool to be used in many biomedical applications and could be potentially translated into clinical work. The challenge of Raman spectroscopy in biomedical applications is the high inherent fluorescence of biological samples. One promising method to suppress the fluorescence background is to use pulsed lasers and time-gated detectors but the complexity of time-gated systems has hindered their widespread usage. We present here chemical imaging of human teeth by means of a new kind of compact and practical fluorescence-suppressed Raman spectrometer based on a time-resolved 16 × 256 CMOS single-photon avalanche diode (SPAD) line sensor with an integrated 256-channel 3-bit on-chip time-to-digital converter. The chemical images were constructed by utilizing a simple unsupervised machine learning algorithm (k-means clustering). The high quality of Raman spectra measured with the time-resolved CMOS SPAD-based Raman spectrometer was verified by comparing the spectra to those collected with a commercial conventional continuous wave (CW) Raman spectrometer. The spectra measured by using the time-resolved CMOS SPAD-based Raman spectrometer had 4.4-8.8 times higher signal to peak-to-peak noise ratio values than the spectra from the CW Raman spectrometer when the same radiant exposure (∼300 J mm-2) was used with both spectrometers. This paper shows in practice the potential of time-resolved CMOS SPAD-based Raman spectroscopy in the field of biomedicine and we expect that the presented technology could pave the way for the development of new kind of compact and practical fluorescence-suppressed Raman spectrometers to be used both in biomedical research and clinical settings.


Assuntos
Análise Espectral Raman , Dente/diagnóstico por imagem , Algoritmos , Humanos , Fótons , Espectrometria de Fluorescência/métodos , Análise Espectral Raman/instrumentação , Análise Espectral Raman/métodos
17.
Int J Nanomedicine ; 14: 5865-5874, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31534328

RESUMO

Purpose: To investigate the effect of precise modeling for Monte Carlo simulations of gold nanoparticles (GNPs) dose-enhanced radiotherapy, two models characterized by their distribution of GNPs in a simulated macroscopic cubic tumor were introduced. The motivation was the widely documented tendency of GNPs to localize around the cell nucleus. Methods: The introduced models composed of 2.7×107 ellipsoid cells, each of them containing a centrally located nucleus as the target for dose evaluation. In the first model, the spheres of GNP are homogeneously distributed in the whole tumor volume, and in the latter, GNPs are localized in the cytoplasms surrounded the nuclei. Results: The results achieved through applying Monte Carlo radiation transports using the Mont Carlo N-Particle eXtended code (MCNPX) show an underestimation of nuclear dose enhancement caused by homogeneous model compared with that of heterogeneous distribution. By investigating various quantities, it was found that subcellular location of GNPs strongly governs the sensitivity of dose enhancement to the number and concentration of GNPs targeted in the tumor. Other obvious differences are revealed by studying the dose enhancement curves in depth of the tumor. While the heterogeneous model predicts an approximately constant dose enhancement in depth for primary photon energies of 50 keV and more, the homogeneous model estimates an energy-dependent increase of about 11 to 30%. Conclusion: It can be concluded that defining a model in accordance with the experimental observations can effectively account for accurate prediction of macroscopic dose enhancement in the target of interest.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Dosagem Radioterapêutica , Núcleo Celular/patologia , Núcleo Celular/efeitos da radiação , Humanos , Método de Monte Carlo , Neoplasias/patologia , Neoplasias/radioterapia , Fótons
18.
Int J Nanomedicine ; 14: 6035-6060, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31534335

RESUMO

Background: The clearance of nanomaterials (NMs) from the liver is essential for clinical safety, and their hepatic clearance is primarily determined by the co-disposition process of various types of hepatic cells. Studies of this process and the subsequent clearance routes are urgently needed for organic NMs, which are used as drug carriers more commonly than the inorganic ones. Materials and methods: In this study, the co-disposition of chitosan-based nanoparticles (CsNps) by macrophages and hepatocytes at both the cellular and animal levels as well as their subsequent biological elimination were investigated. RAW264.7 and Hepa1-6 cells were used as models of Kupffer cells and hepatocytes, respectively. Results: The cellular studies showed that CsNps released from RAW264.7 cells could enter Hepa1-6 cells through both clathrin- and caveolin-mediated endocytosis. The transport from Kupffer cells to hepatocytes was also studied in mice, and it was observed that most CsNps localized to the hepatocytes after intravenous injection. Following the distribution in hepatocytes, the hepatobiliary-fecal excretion route was shown to be the primary elimination route for CsNps, besides the kidney-urinary excretion route. The elimination of CsNps in mice was a lengthy process, with a half time of about 2 months. Conclusion: The demonstration in this study of the transport of CsNps from macrophages to hepatocytes and the subsequent hepatobiliary-fecal excretion provides basic information for the future development and clinical application of NMs.


Assuntos
Quitosana/farmacologia , Hepatócitos/citologia , Hepatócitos/metabolismo , Nanopartículas/química , Animais , Transporte Biológico , Linhagem Celular Tumoral , Portadores de Fármacos/metabolismo , Exocitose , Hepatócitos/efeitos dos fármacos , Cinética , Fígado/metabolismo , Macrófagos/metabolismo , Camundongos , Nanopartículas/ultraestrutura , Fótons
19.
Int J Radiat Biol ; 95(11): 1543-1546, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31550183

RESUMO

Introduction: In multi-well cell culture plates, wells are bordered by air cavities. The air cavity inhomogeneities can reduce the amount of delivered dose. In this study, the effect of these cavities on cell survival was investigated.Materials and methods: A special phantom was designed to house the plates and air cavities were filled by water equivalent materials. Cultured melanoma cells were irradiated using 6MV photon for 200 cGy. MTT and clonogenic assay tests were used to evaluate cell survival.Results: Results of MTT assay showed mean survival percentage for irradiated cells in the first group, i.e. plates with air cavities, was 18.9% higher than the second group with air cavities filled with paraffin. Clonogenic assay results showed a maximum of 37% difference in the mean of number of colonies between the first group and the second group (p value < .05).Conclusions: The presence of air cavities in multi-well cell culture plates reduced radiation cell kill by up to 37%. To ensure the accuracy of delivered dose, it is necessary to replace the air cavities as well as the air surrounding the plates by a water equivalent material.


Assuntos
Ar , Técnicas de Cultura de Células , Sobrevivência Celular/efeitos da radiação , Melanoma/radioterapia , Neoplasias Cutâneas/radioterapia , Bioensaio , Linhagem Celular , Simulação por Computador , Raios gama , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Fótons , Polimetil Metacrilato , Radiobiologia , Água
20.
Int J Radiat Biol ; 95(12): 1685-1695, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31490703

RESUMO

Purpose: Estimation of energy absorption buildup factors (EABFs) of some human tissues for photon energies commonly used in brachytherapy (BT) and external beam radiotherapy (EBRT).Methods: A five parameter geometric progression (G-P) fitting approximation was used to estimate EABF at different energies and penetration depths (up to 20 mfp). MCNP6.1 was used to obtain EABF for comparison.Results: For radiation sources with lower mean energies (MEs), adipose tissue, which has lowest Zeq, has highest EABF values while bone, which has highest Zeq, has lowest EABF values. EABF reaches to a maximum value (EABFmax∼550) for Ir-192 BT source, which has a mean energy of 0.35 MeV. The radiation sources (MEs from 300 keV to a few MeV) were found to have higher values of EABF. At higher energies, e.g. 5 MeV, the annihilation photons contribute EABF at higher penetration depths, e.g. 20 mfp. In general, both MCNP and GP fitted EABF values along with available experimental data were found to agree well.Conclusions: EABFs of various human tissues have been investigated at radiation source energies relevant to BT and EBRT extensively. The presented data on EABF for the human tissues should be useful for accurate dose estimation at BT and EBRT.


Assuntos
Absorção de Radiação , Braquiterapia , Humanos , Especificidade de Órgãos , Fótons
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