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1.
Anal Bioanal Chem ; 411(27): 7055-7059, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31598742

RESUMO

A new perspective on the relevant problem-creating simple, rapid, and efficient protein sensors based on microstructured optical fibers using a simple homogeneous analysis format-was proposed. Commercially available long-period grating hollow core microstructured optical fibers (LPG HCMOF) were used to determine bovine serum albumin (BSA) and albumin from chicken eggs (OVA) in binary mixtures as well as immunoglobulin G (IgG) in the presence of BSA and OVA. LPG HCMOF transmission spectra allowed the detection of both BSA and OVA up to 10 mg/mL with LOD as low as 0.1 and 0.8 µg/mL, respectively. Partial least squares regression (PLS) was utilized for modeling of LPG HCMOF spectral data and quantitative analysis of BSA, OVA, total protein, and IgG in binary and ternary mixtures. Rather high coefficients of determination (R2) and low root mean square error for the calibration (RMSEC) (15%) and prediction (RMSEP) (20%) were obtained for all PLS models. The proposed approach was tested in the analysis of BSA in spiked horse blood hemolyzed (HBH). The results demonstrated the functionality of the proposed approach and offered the opportunity for the creation of a wide range of sensors for protein determination in complex mixtures. Graphical abstract.


Assuntos
Imunoglobulina G/análise , Ovalbumina/análise , Soroalbumina Bovina/análise , Animais , Análise Química do Sangue/métodos , Bovinos , Galinhas , Cavalos , Análise dos Mínimos Quadrados , Camundongos , Modelos Moleculares , Fibras Ópticas
2.
Environ Sci Technol ; 53(18): 10880-10887, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31397559

RESUMO

Pathogenic bacteria pose a health threat and operational challenge in drinking water. UV-C light-emitting diodes (UV-C LEDs) are becoming a competitive disinfection technology but are limited by their small irradiation area. Side-emitting optical fibers (SEOFs) can serve as a UV-C LED light delivery technology for reactors or tubing. Modifying the surfaces of conventional optical fibers with scattering centers allows for side emission of 265 nm radiation from an LED for microbial inactivation in water. Solid-material absorbance and flux measurements differentiated light absorption from scattering for all materials. Silica spheres >200 nm in diameter achieved higher scattering than smaller silica. A critical discovery was that treating the silica-coated optical fiber in a solution of high ionic strength increased UV-C side emission by greater than 6-fold. Additionally, the cladding polymer Cytop had negligible absorbance at 265 nm wavelength. A scalable four-step treatment process was developed to fabricate the novel SEOF. Attached to a 265 nm LED, the side-emitting optical fiber achieved 2.9 log inactivation of Escherichia coli at a delivery dose of 15 mJ/cm2. The results illustrate proof of concept that UV-C SEOFs can inactivate E. coli and should be further explored for delivering LED light into water.


Assuntos
Nanopartículas , Purificação da Água , Desinfecção , Escherichia coli , Fibras Ópticas , Polímeros , Raios Ultravioleta , Água , Microbiologia da Água
3.
Anal Bioanal Chem ; 411(26): 6813-6823, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31432237

RESUMO

We demonstrate a DNA-based optical fiber device that uses an in-fiber grating, a light absorbing coating with surface anchored DNA, and a built-in optical thermometer. This device is used for precisely thermal cycling surface DNA spots bound by a simple UV cross-linking technique. Near-infrared light of wavelengths near 1550 nm and guided power near 300 mW is coupled out of the fiber core by a tilted fiber Bragg grating inscribed in the fiber and absorbed by the coating to increase its temperature to more than 95 °C. A co-propagating broadband light signal (also in the near-infrared region) is used to measure the reflection spectrum of the grating and thus the temperature from the wavelength shifts of the reflection peaks. The device is capable of sensitive DNA melt analysis and can be used for DNA amplification. Graphical abstract.


Assuntos
Técnicas Biossensoriais/instrumentação , DNA/química , Tecnologia de Fibra Óptica/instrumentação , Hibridização de Ácido Nucleico , DNA/genética , Desenho de Equipamento , Calefação , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Desnaturação de Ácido Nucleico , Fibras Ópticas
4.
Rev. ADM ; 76(4): 194-200, jul.-ago 2019. ilus, tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1023068

RESUMO

La gutapercha es químicamente un polímero a base de isopreno, impermeable, no poroso y radiopaco entre otras características, empleado desde el siglo XIX; sin embargo manifiesta algunos inconvenientes propios del material, lo cual ha dado lugar al nacimiento de otros materiales para mejorar sus propiedades. Recientemente se ha desarrollado y caracterizado un material novedoso a base de fibra óptica recubierta por nano partículas de plata (FONP), propuesto como un material alternativo para la obturación de conductos radiculares. En el presente estudio se seleccionaron 24 dientes para conformar cuatro grupos experimentales comparativos entre la obturación con fibra óptica y con gutapercha, ambos con el sellador AH Plus. Las raíces fueron obturadas en grupos de diez y almacenadas en solución salina a 37 oC. La filtración apical se midió desde el extremo apical de la interfaz del material hasta la extensión más coronal del tinte observado microscópicamente. Se empleó la herramienta de LAS EZ V3.0 (Leica Microsystems, Switzerland), los datos se tabularon y se analizaron. Resultados: Las mediciones de microfiltración a nivel apical e intraconductos manifestaron diferencias en favor de la gutapercha, donde los grupos experimentales manifestaron una filtración promedio correspondiente a 0.872 mm en el grupo de Gutapercha/AH-PLUS y de 2.390 mm con técnica lateral utilizando FONP/AH-PLUS, aun así se evidenció que las propiedades de sellado de la fibra óptica con nanopartículas fueron suficientes para considerarlo como un material de obturación de conductos radiculares dentales como posible sustituto de la gutapercha (AU)


Gutta-percha is chemically an Isoprene-based polymer, impervious, non-porous and radiopaque, among other characteristics, used since the 19th century, it manifests some disadvantages inherent to the material, which has led to the birth of new materials with improved properties. Recently, a novel material based on optical fiber covered by silver nanoparticles (FONP) has been developed, characterized and proposed as an alternative material for root canal obturation. In the present study, 24 teeth were selected and divided into four comparative experimental groups for obturation with fiber optics and gutta-percha, both with the AH Plus sealer. The roots were sealed in groups of ten and stored in saline at 37 oC. Apical filtration test was performed from the apical end of the material interface to the most coronal extension of the dye observed microscopically. The LAS EZ V3.0 tool was used to make the measurements and the data was tabulated and analyzed. Results: Measurements of microfiltration at the apical and intracanal level showed differences in favor of gutta-percha, where the experimental groups showed an average filtration of 0.872 mm in the Gutapercha/AH-PLUS group and 2.390 mm using FONP/AH-PLUS, even so, it was evidenced that the sealing properties of the optical fiber with nanoparticles are sufficient to consider this material as a proper filling material for dental root canals as a substitute for gutta-percha (AU)


Assuntos
Materiais Restauradores do Canal Radicular , Fibras Ópticas , Guta-Percha , Técnicas In Vitro , Projetos Piloto , Análise Estatística , Compostos de Prata , Infiltração Dentária , Nanopartículas Metálicas
5.
Sensors (Basel) ; 19(14)2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31323734

RESUMO

Advances in medicine and improvements in life quality has led to an increase in the life expectancy of the general population. An ageing world population have placed demands on the use of assistive technology and, in particular, towards novel healthcare devices and sensors. Besides the electromagnetic field immunity, polymer optical fiber (POF) sensors have additional advantages due to their material features such as high flexibility, lower Young's modulus (enabling high sensitivity for mechanical parameters), higher elastic limits, and impact resistance. Such advantages are well-aligned with the instrumentation requirements of many healthcare devices and in movement analysis. Aiming at these advantages, this review paper presents the state-of-the-art developments of POF sensors for healthcare applications. A plethora of healthcare applications are discussed, which include movement analysis, physiological parameters monitoring, instrumented insoles, as well as instrumentation of healthcare robotic devices such as exoskeletons, smart walkers, actuators, prostheses, and orthosis. This review paper shows the feasibility of using POF sensors in healthcare applications and, due to the aforementioned advantages, it is possible to envisage a further widespread use of such sensors in this research field in the next few years.


Assuntos
Técnicas Biossensoriais/tendências , Tecnologia de Fibra Óptica/tendências , Fibras Ópticas , Humanos , Polímeros/química
6.
ACS Appl Mater Interfaces ; 11(31): 28546-28553, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31309830

RESUMO

This work reports an interferometric optical microfiber sensor functionalized with nitrogen- and sulfur-codoped carbon dots (CDs) for the detection of ferric ions (Fe3+). Compared to other CD-based ferric ion sensors, the sensing mechanism of this presented sensor is dependent on the refractive index modulations due to selective Fe3+ adsorption onto the CD binding sites at the tapered region. This is the first study in which CD-based sensing was performed at the solid phase as a chelator, which does not rely on its fluorescence properties. The detection performance of the proposed sensor is not only comparable to a conventional fluorescence-based CD nanoprobe sensor but also capable of delivering quantitative analysis results and ease of translation to a sensor device for on-site detection. The presented sensor exhibits Fe3+ detection sensitivity of 0.0061 nm/(µg/L) in the linear detection range between 0 and 300 µg/L and a detection limit of 0.77 µg/L based on the Langmuir isotherm model. Finally, the potential use of the CD-functionalized optical microfiber sensor in the real environmental and biological Fe3+ monitoring applications has also been validated in this work.


Assuntos
Carbono/química , Compostos Férricos/análise , Fluorescência , Fibras Ópticas , Pontos Quânticos/química , Compostos Férricos/química , Interferometria , Luz , Limite de Detecção
7.
Biosens Bioelectron ; 142: 111506, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325674

RESUMO

Saccharide sensors represent a broad research area in the scope of sensing devices and their involvement in the medical diagnosis field is particularly relevant for cancer detection at early stage. In that context, we present a non-enzymatic optical fiber-based sensor that makes use of plasmon-assisted tilted fiber Bragg gratings (TFBGs) functionalized for D-glucose biosensing through polydopamine (PDA)-immobilized concanavalin A (Con A). Our probe allows a live and accurate monitoring of the PDA layer deposition leading improved surface biochemistry. The SPR shift observed was assessed to 3.83 ±â€¯0.05 nm within 20 min for a 2 mg/mL dopamine solution. Tests performed in different D-Glucose solutions have revealed a limit of detection close to 10-7 M with the highest sensitivity in the 10-6 to 10-4 M range. This configuration has the capability to overcome the limitations of current enzyme-based solutions.


Assuntos
Concanavalina A/química , Glucose/análise , Indóis/química , Polímeros/química , Ressonância de Plasmônio de Superfície/métodos , Desenho de Equipamento , Humanos , Proteínas Imobilizadas/química , Limite de Detecção , Fibras Ópticas , Ressonância de Plasmônio de Superfície/instrumentação
8.
Opt Lett ; 44(13): 3350-3353, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31259958

RESUMO

Endogenous and exogenous fluorescence emission from biological samples encodes complementary information. Here we report, to the best of our knowledge, the first results from an optical imaging platform with interleaved excitation and detection of exogenous and endogenous fluorescence from tissue samples using a single flexible multimode fiber that delivers the excitation beam and collects the emitted light. A custom-built reflective optical chopper wheel with synchronized rotation temporally multiplexes an autofluorescence lifetime imaging apparatus with an intensity-based fluorescence module tailored to imaging green fluorescent protein. We demonstrate the functionality of such platform imaging dyes of varying fluorescence signatures and resolving cellularized areas on bio-engineered tissue constructs.


Assuntos
Fibras Ópticas , Imagem Óptica/instrumentação , Animais , Bovinos , Corantes Fluorescentes/química , Pericárdio/diagnóstico por imagem , Fatores de Tempo
9.
Sensors (Basel) ; 19(13)2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31288468

RESUMO

The objective of this paper is to study the ability of polymer optical fiber (POF) to be inserted in a knitted fabric and to measure both pressure and friction when walking. Firstly, POF, marketed and in development, have been compared in terms of the required mechanical properties for the insertion of the fiber directly into a knitted fabric on an industrial scale, i.e. elongation, bending rigidity, and minimum bending radius before plastic deformation. Secondly, the chosen optical fiber was inserted inside several types of knitted fabric and was shown to be sensitive to friction and compression. The knitted structure with the highest sensitivity has been chosen for sock prototype manufacturing. Finally, a feasibility study with an instrumented sock showed that it is possible to detect the different phases of walking in terms of compression and friction.


Assuntos
Vestuário , Monitorização Fisiológica/instrumentação , Fibras Ópticas , Têxteis , Acelerometria , Desenho de Equipamento , Fricção , Humanos , Monitorização Fisiológica/métodos , Polímeros , Pressão , Reprodutibilidade dos Testes , Caminhada
10.
Biosens Bioelectron ; 142: 111505, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357154

RESUMO

Surface plasmon resonance (SPR) technology has effectively bolstered optic fiber sensing in fields of life science, clinical diagnosis, medicine, food safety and so on. The current review outlines the research status of fiber optic biosensor based on SPR, and the merits of optical fiber sensor and the development of optical fiber sensor based on SPR are completely covered. An in-depth review of four devices for generating SPR is presented, and optical fiber is finally adopted for a substrate to generate SPR. Different prototypes of optical fiber biosensor based on SPR are meticulously outlined: optical fiber grating biosensor based on SPR and optical fiber structured type biosensor based on SPR, and representative instances from literature are presented to verify the latest advancements in this potentially valuable research avenue. In addition, the sensing performance of different optical fiber structured type biosensor based on SPR are compared. What's more, simultaneous multi-parameter detection and improvement of sensitivity are discussed and summarized. The article concludes identify key challenges and develop orientation of optical fiber biosensor based on SPR.


Assuntos
Tecnologia de Fibra Óptica/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Animais , Desenho de Equipamento , Tecnologia de Fibra Óptica/métodos , Humanos , Fibras Ópticas , Ressonância de Plasmônio de Superfície/métodos
11.
Sensors (Basel) ; 19(11)2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31195714

RESUMO

The distributed feedback (DFB) laser is widely used in sensing because of its portable size, simple fabrication and high sensitivity. Most theoretical design models are based on passive Bragg gratings. However, passive grating models cannot be used to predict sensor performance using the important indicator of figure of merit (FOM) through theoretical calculations. To solve this problem, we replaced the passive grating with an active grating by using the imaginary part of the coupling constant that represents the value of the gain. As a comparison, the influence of the full width at half maximum (FWHM) and sensitivity were analyzed for different grating duty cycles and depths in the passive grating sensors. To obtain a higher FOM in the active grating sensors, we systematically investigated the effects of duty cycle and gain value through numerical simulations. We found that the redshift caused by a duty cycle increase can improve the sensitivity of biomolecule detection by 1.7 times.


Assuntos
Técnicas Biossensoriais , Desenho de Equipamento/métodos , Tecnologia de Fibra Óptica , Retroalimentação , Lasers , Luz , Fibras Ópticas
12.
Sensors (Basel) ; 19(13)2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31252623

RESUMO

This study demonstrated a measurement approach for biomolecules at the picoliter scale, using a newly developed picoliter cuvette inside an optical fiber constructed via near-ultraviolet femtosecond laser drilling. The sensing capacity was estimated to be within 0.4-1.2 pL due to an optical path length of 3-5 microns, as measured by scanning electron microscopy (SEM). The picoliter cuvette exhibited a change in the optical extinction spectrum after addition of biomolecules such as L-cysteine, in conjunction with a gold nanoparticle (GNP) dispersion solution, following a simple measurement configuration involving a small white light source and a compact spectrometer. A linear attenuation of the spectral dip near a wavelength of 520 nm was observed as the L-cysteine concentration was increased at 4 wt% of the GNP mass concentration. The measurement resolution of the concentration using the picoliter cuvette was evaluated at 0.125 mM. The experimental results showed the difference in aggregation processes caused by a different concentration of GNPs. Moreover, they revealed the ability of the picoliter cuvette to verify whether the concentration of GNPs in the liquid sample correspondingly determines homogeneous or inhomogeneous GNP aggregation, as supported by SEM observation and numerical calculations based on Mie theory.


Assuntos
Cisteína/isolamento & purificação , Nanopartículas Metálicas/química , Fibras Ópticas , Cisteína/química , Ouro/química , Lasers , Tamanho da Partícula , Refratometria , Ressonância de Plasmônio de Superfície
13.
Nat Commun ; 10(1): 2536, 2019 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182714

RESUMO

Optical fiber-mediated optogenetic activation and neuronal Ca2+ recording in combination with fMRI provide a multi-modal fMRI platform. Here, we developed an MRI-guided robotic arm (MgRA) as a flexible positioning system with high precision to real-time assist optical fiber brain intervention for multi-modal animal fMRI. Besides the ex vivo precision evaluation, we present the highly reliable brain activity patterns in the projected basal forebrain regions upon MgRA-driven optogenetic stimulation in the lateral hypothalamus. Also, we show the step-wise optical fiber targeting thalamic nuclei and map the region-specific functional connectivity with whole-brain fMRI accompanied by simultaneous calcium recordings to specify its circuit-specificity. The MgRA also guides the real-time microinjection to specific deep brain nuclei, which is demonstrated by an Mn-enhanced MRI method. The MgRA represents a clear advantage over the standard stereotaxic-based fiber implantation and opens a broad avenue to investigate the circuit-specific functional brain mapping with the multi-modal fMRI platform.


Assuntos
Imagem por Ressonância Magnética/instrumentação , Optogenética/instrumentação , Procedimentos Cirúrgicos Robóticos/instrumentação , Animais , Cálcio/metabolismo , Channelrhodopsins , Neuroimagem Funcional/instrumentação , Neuroimagem Funcional/métodos , Imagem por Ressonância Magnética/métodos , Masculino , Fibras Ópticas , Optogenética/métodos , Ratos Sprague-Dawley
14.
Appl Opt ; 58(17): 4806-4811, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31251304

RESUMO

A novel, to the best of our knowledge, liquid crystal (LC) biosensor, based on an optical fiber Mach-Zehnder interferometer (MZI), is proposed. The proposed optical fiber MZI consists of two single-mode fibers and a tapered photonic crystal fiber (PCF). The PCF is coated with 4'-pentyl-biphenyl-4-carboxylic acid (PBA)-doped 4-cyano-4'-pentylbiphenyl (5CB). Being a pH-sensitive material, PBA can manipulate LC molecules to different orientations according to their pH values. When the orientation of LC molecules changes with varying pH, the effective refractive index of the cladding modes also is accordingly affected. Enzymatic reactions of penicillinase can release H+, which causes the decrease of the pH. Therefore, the enzymatic reactions of penicillinase can be sensed by monitoring the peak shift in the interference spectrum. The effects of the tapered diameter on the sensitivity of the sensor were experimentally investigated as well.


Assuntos
Técnicas Biossensoriais , Interferometria/instrumentação , Cristais Líquidos/química , Penicilinase/metabolismo , Bacillus cereus/enzimologia , Concentração de Íons de Hidrogênio , Fibras Ópticas , Penicilina G/metabolismo
15.
Invest Ophthalmol Vis Sci ; 60(7): 2563-2570, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31212308

RESUMO

Purpose: Photochemical crosslinking of the sclera is an emerging technique that may prevent excessive eye elongation in pathologic myopia by stiffening the scleral tissue. To overcome the challenge of uniform light delivery in an anatomically restricted space, we previously introduced the use of flexible polymer waveguides. We presently demonstrate advanced waveguides that are optimized to deliver light selectively to equatorial sclera in the intact orbit. Methods: Our waveguides consist of a polydimethylsiloxane cladding and a polyurethane core, coupled to an optical fiber. A reflective silver coating deposited on the top and side surfaces of the waveguide prevents light leakage to nontarget, periorbital tissue. Postmortem rabbits were used to test the feasibility of in situ equatorial sclera crosslinking. Tensometry measurements were performed on ex vivo rabbit eyes to confirm a biomechanical stiffening effect. Results: Metal-coated waveguides enabled efficient light delivery to the entire circumference of the equatorial sclera with minimal light leakage to the periorbital tissues. Blue light was delivered to the intact orbit with a coefficient of variation in intensity of 22%, resulting in a 45 ± 11% bleaching of riboflavin fluorescence. A 2-fold increase in the Young's modulus at 5% strain (increase of 92% P < 0.05, at 25 J/cm2) was achieved for ex vivo crosslinked eyes. Conclusions: Flexible polymer waveguides with reflective, biocompatible surfaces are useful for sclera crosslinking to achieve targeted light delivery. We anticipate that our demonstrated procedure will be applicable to sclera crosslinking in live animal models and, potentially, humans in vivo.


Assuntos
Reagentes para Ligações Cruzadas , Fibras Ópticas , Órbita/efeitos dos fármacos , Fármacos Fotossensibilizantes/uso terapêutico , Riboflavina/uso terapêutico , Esclera/metabolismo , Raios Ultravioleta , Animais , Fenômenos Biomecânicos , Materiais Revestidos Biocompatíveis , Colágeno/metabolismo , Módulo de Elasticidade , Órbita/metabolismo , Polímeros , Coelhos , Prata
16.
Int J Nanomedicine ; 14: 2349-2369, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31040661

RESUMO

Background: In view of the growing importance of nanotechnologies, the detection/identification of nanoparticles type has been considered of utmost importance. Although the characterization of synthetic/organic nanoparticles is currently considered a priority (eg, drug delivery devices, nanotextiles, theranostic nanoparticles), there are many examples of "naturally" generated nanostructures - for example, extracellular vesicles (EVs), lipoproteins, and virus - that provide useful information about human physiology or clinical conditions. For example, the detection of tumor-related exosomes, a specific type of EVs, in circulating fluids has been contributing to the diagnosis of cancer in an early stage. However, scientists have struggled to find a simple, fast, and low-cost method to accurately detect/identify these nanoparticles, since the majority of them have diameters between 100 and 150 nm, thus being far below the diffraction limit. Methods: This study investigated if, by projecting the information provided from short-term portions of the back-scattered laser light signal collected by a polymeric lensed optical fiber tip dipped into a solution of synthetic nanoparticles into a lower features dimensional space, a discriminant function is able to correctly detect the presence of 100 nm synthetic nanoparticles in distilled water, in different concentration values. Results and discussion: This technique ensured an optimal performance (100% accuracy) in detecting nanoparticles for a concentration above or equal to 3.89 µg/mL (8.74E+10 particles/mL), and a performance of 90% for concentrations below this value and higher than 1.22E-03 µg/mL (2.74E+07 particles/mL), values that are compatible with human plasmatic levels of tumor-derived and other types of EVs, as well as lipoproteins currently used as potential biomarkers of cardiovascular diseases. Conclusion: The proposed technique is able to detect synthetic nanoparticles whose dimensions are similar to EVs and other "clinically" relevant nanostructures, and in concentrations equivalent to the majority of cell-derived, platelet-derived EVs and lipoproteins physiological levels. This study can, therefore, provide valuable insights towards the future development of a device for EVs and other biological nanoparticles detection with innovative characteristics.


Assuntos
Tecnologia Biomédica/métodos , Técnicas Biossensoriais/métodos , Nanopartículas/química , Fibras Ópticas , Análise Discriminante , Exossomos/química , Vesículas Extracelulares , Análise de Fourier , Humanos , Polímeros/química , Soluções
17.
Biomater Sci ; 7(7): 2812-2825, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31066391

RESUMO

Among brain tumors, glioblastoma multiforme (GBM) is the most common and aggressive form (WHO grade IV) with a median survival of only 14.6 months in adults. Photodynamic therapy (PDT) is a combination of a photosensitizer (PS), light and molecular oxygen, and considered a promising treatment for GBM. Therapeutic outcomes of PDT rely on ROS generation in a tumor microenvironment, which can be controlled with dual selectivity by localization of the photosensitizer and confinement of light to the targeted tumor microenvironment. We previously demonstrated the photodynamic anticancer efficacy of mitochondrial-targeted photosensitizer-loaded albumin nanoparticles (PS@chol-BSA NPs). In this study, the photodynamic therapeutic effect of PS@chol-BSA NPs was further enhanced by confinement of light using a fiber optic cannula in orthotopic GBM-xenografted mice. In vitro cellular uptake and phototoxicity of PS@chol-BSA NPs were evaluated in brain tumor (U87MG) and endothelial (bEnd.3) cells. In vivo biodistribution was determined by an in vivo imaging system (IVIS) and the photodynamic efficacy was evaluated with confined laser irradiation. PS@chol-BSA NPs showed higher cellular uptake and phototoxicity in U87MG cells than in bEnd.3 cells. PS@chol-BSA NPs showed a brain tumor accumulation of 0.2%ID within 2 h and remain in the brain tumor for 22 h. When compared to the control group, there was remarkable suppression in tumor growth by laser irradiation with and without the fiber optic cannula at a dose of 1 mg kg-1, in which significant tumor suppression up to 40% was observed with confined laser irradiation. Together, dual-selective photodynamic therapy with a mitochondria-targeted photosensitizer and fiber optic cannula provides a promising therapeutic strategy for malignant brain tumors.


Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Cânula , Glioblastoma/tratamento farmacológico , Mitocôndrias/metabolismo , Fibras Ópticas , Fotoquimioterapia/instrumentação , Fármacos Fotossensibilizantes/farmacologia , Animais , Neoplasias Encefálicas/patologia , Bovinos , Linhagem Celular Tumoral , Portadores de Fármacos/química , Glioblastoma/patologia , Humanos , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/efeitos da radiação , Nanopartículas/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacocinética , Soroalbumina Bovina/química , Distribuição Tecidual
18.
Biosens Bioelectron ; 137: 25-32, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31077987

RESUMO

Continuous glucose monitoring facilitates the stringent control of blood glucose concentration in diabetic and intensive care patients. Optical fibers have emerged as an attractive platform; however, their practical applications are hindered due to lack of biocompatible fiber materials, complex and non-practical readout approaches, slow response, and time-consuming fabrication processes. Here, we demonstrate the quantification of glucose by smartphone-integrated fiber optics that overcomes existing technical limitations. Simultaneously, a glucose-responsive hydrogel was imprinted with an asymmetric microlens array and was attached to a multimode silica fiber's tip during photopolymerization, and subsequent interrogated for glucose sensing under physiological conditions. A smartphone and an optical power meter were employed to record the output signals. The functionalized fiber showed a high sensitivity (2.6 µW mM-1), rapid response, and a high glucose selectivity in the physiological glucose range. In addition, the fiber attained the glucose complexation equilibrium within 15 min. The lactate interference was also examined and it was found minimal ∼0.1% in the physiological range. A biocompatible hydrogel made of polyethylene glycol diacrylate was utilized to fabricate a flexible hydrogel fiber to replace the silica fiber, and the fiber's tip was functionalized with the glucose-sensitive hydrogel during the ultraviolet light curing process. The biocompatible fiber was quickly fabricated by the molding, the readout approach was facile and practical, and the response to glucose was comparable to the functionalized silica fiber. The fabricated optical fiber sensors may have applications in wearable and implantable point-of-care and intensive-care continuous monitoring systems.


Assuntos
Técnicas Biossensoriais , Glicemia/isolamento & purificação , Tecnologia de Fibra Óptica , Glicemia/química , Automonitorização da Glicemia , Humanos , Hidrogéis/química , Fibras Ópticas
19.
Neurosci Bull ; 35(3): 425-433, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31062336

RESUMO

Fiber photometry is a sensitive and easy way to detect changes in fluorescent signals. The combination of fiber photometry with various fluorescent biomarkers has substantially advanced neuroscience research over the last decade. Despite the wide use of fiber photometry in biomedical fields, the lack of a detailed and comprehensive protocol has limited progress and sometimes complicated the interpretation of data. Here, we describe detailed procedures of fiber photometry for the long-term monitoring of neuronal activity in freely-behaving animals, including surgery, apparatus setup, data collection, and analysis.


Assuntos
Encéfalo/metabolismo , Sinalização do Cálcio , Neurônios/metabolismo , Imagem Óptica/métodos , Fotometria/métodos , Animais , Feminino , Masculino , Camundongos , Procedimentos Neurocirúrgicos , Fibras Ópticas , Imagem Óptica/instrumentação , Fotometria/instrumentação
20.
Sensors (Basel) ; 19(9)2019 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-31083614

RESUMO

An optical cavity-based sensor using a differential detection method has been proposed for point-of-care diagnostics. We developed a low-cost and portable optical cavity-based sensor system using a 3D printer and off-the-shelf optical components. In this paper, we demonstrate the sensing capability of the portable system through refractive index measurements. Fabricated optical cavity samples were tested using the portable system and compared to simulation results. A referencing technique and digital low pass filtering were applied to reduce the noise of the portable system. The measurement results match the simulation results well and show the improved linearity and sensitivity by employing the differential detection method. The limit of detection achieved was 1.73 × 10-5 Refractive Index Unit (RIU), which is comparable to other methods for refractive index sensing.


Assuntos
Técnicas Biossensoriais/economia , Técnicas Biossensoriais/métodos , Desenho de Equipamento/métodos , Fibras Ópticas , Refratometria/métodos
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