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1.
Nat Commun ; 11(1): 4489, 2020 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-32895384

RESUMO

We report a covalent chemistry-based hepatocellular carcinoma (HCC)-specific extracellular vesicle (EV) purification system for early detection of HCC by performing digital scoring on the purified EVs. Earlier detection of HCC creates more opportunities for curative therapeutic interventions. EVs are present in circulation at relatively early stages of disease, providing potential opportunities for HCC early detection. We develop an HCC EV purification system (i.e., EV Click Chips) by synergistically integrating covalent chemistry-mediated EV capture/release, multimarker antibody cocktails, nanostructured substrates, and microfluidic chaotic mixers. We then explore the translational potential of EV Click Chips using 158 plasma samples of HCC patients and control cohorts. The purified HCC EVs are subjected to reverse-transcription droplet digital PCR for quantification of 10 HCC-specific mRNA markers and computation of digital scoring. The HCC EV-derived molecular signatures exhibit great potential for noninvasive early detection of HCC from at-risk cirrhotic patients with an area under receiver operator characteristic curve of 0.93 (95% CI, 0.86 to 1.00; sensitivity = 94.4%, specificity = 88.5%).


Assuntos
Biomarcadores Tumorais/isolamento & purificação , Carcinoma Hepatocelular/diagnóstico , Detecção Precoce de Câncer/métodos , Vesículas Extracelulares/genética , Neoplasias Hepáticas/diagnóstico , Idoso , Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/sangue , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Estudos de Casos e Controles , Química Click/instrumentação , Química Click/métodos , Química Computacional , Simulação por Computador , Diagnóstico Diferencial , Dimetilpolisiloxanos/química , Progressão da Doença , Detecção Precoce de Câncer/instrumentação , Feminino , Células Hep G2 , Humanos , Dispositivos Lab-On-A-Chip , Biópsia Líquida/instrumentação , Biópsia Líquida/métodos , Cirrose Hepática/sangue , Cirrose Hepática/patologia , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Masculino , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Pessoa de Meia-Idade , Nanoestruturas/química , Nanofios/química , Estadiamento de Neoplasias , RNA Mensageiro/genética , RNA Mensageiro/isolamento & purificação , Curva ROC , Reação em Cadeia da Polimerase Via Transcriptase Reversa/instrumentação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos
2.
J Chromatogr A ; 1626: 461349, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797829

RESUMO

In the present work, a very sensitive and fully automated direct immersion PAL SPME Arrow procedure, coupled with GC-MS, has been developed and validated for determination of nine phosphorus flame retardants in different types of water samples (river, drinking and rainwater). PDMS/DVB was selected among three commercially available SPME Arrows (PDMS/DVB, DVB/PDMS/CWR and PDMS/CWR), since it resulted in the best sensitivity. The important experimental parameters were optimized via a central composite design response surface methodology and as result, extraction time of 65 min, extraction temperature of 80 °C and added salt concentration of 19% (w/v), were selected as the optimum values. The optimized method showed linear response over the calibration range (2 - 500 ng L-1), with R2-values higher than 0.9937. The precision (RSD%) measured by replicate analyses (n = 7) was estimated at 2 and 100 ng L-1 and was less than 29% and 21%, respectively. The LOQ of PAL SPME Arrow, calculated as S/N = 10, was between 0.2 and 1.2 ng L-1 (for triphenyl phosphate and tris-(1­chloro­2-propyl) phosphate, respectively) with extraction efficiencies between 5.9 and 31% (for tris-(1,3-dichloro-2-propyl) phosphate and tri-n­butyl phosphate, respectively). To assess the performance of the developed technique for real samples, two river water samples, tap water from two regions and a rainwater sample were analyzed. Most of the target analytes were observed in the river samples with concentrations of 1.0 - 250 ng L-1 and the obtained recoveries at 50 ng L-1 ranged between 60 and 107%. Considering the figures of merit of the optimized method, PAL SPME Arrow-GC-MS showed to be the most sensitive analytical approach for determination of phosphorus flame retardants in water, with satisfying precision and accuracy, compared with conventional SPME-NPD, LLE-GC-MS and SPE-LC-MS/MS.


Assuntos
Retardadores de Chama/análise , Fósforo/análise , Microextração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Automação , Dimetilpolisiloxanos/química , Cromatografia Gasosa-Espectrometria de Massas , Polivinil/química , Soluções
3.
Int J Nanomedicine ; 15: 5405-5416, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801696

RESUMO

Purpose: Although the effective and safe medical defoamers, dimethicone (DM) and simethicone (SM) are widely used in electronic gastroscope examination (EGE), their preparations are presented in the form of suspensions or emulsions, these are untransparent or milk-like in appearance and can easily cause misdiagnosis as a result of an unclear field of vision if the doctor does not master the amount of defoamer or operates incorrectly. At the same time, it is also difficult to wash out the camera and pipeline, due to the large oil droplets of preparations. The purpose of this study was to develop a new clear and transparent oil in water (O/W) DM nanoemulsions (DMNs) and observe the effect of application in EGE. Methods: The oil phase was chosen for its antifoaming activity and viscosity. The emulsifier and co-emulsifier were selected according to the solubility of the oil phase in them. The water titration method was used to make the pseudoternary phase diagrams of nanoemulsions and optimize the prescription composition. DM-in-water nanoemulsion was prepared by the low energy method and evaluated for appearance, antifoaming ability, droplet size, and stability. The effect of DMNs utilized in EGEs was also observed. Results: The optimal formulation of DMNs contained CRH-40 as an emulsifier, PEG-400 as a co-emulsifier, DM as oil phase with the viscosity of 10 mPa.s, and their proportion was 4.5:4.5:1, respectively. DMNs obtained the average particle size of 67.98 nm with the polydispersity index (PDI) of 0.332, and 57.14% defoaming rate. The result of using an EGE showed that DMNs were superior in comparison to the emulsions with regard to the defoaming effect, visual clarity, and easy cleanup. Conclusion: DMNs were found to provide excellent visual clarity to its other preparations. The novel DMNs is a promising substitute for DM emulsions or suspensions in EGEs.


Assuntos
Antiespumantes/química , Dimetilpolisiloxanos/química , Emulsões/química , Gastroscopia/métodos , Antiespumantes/efeitos adversos , Antiespumantes/uso terapêutico , Óleo de Rícino/química , Dimetilpolisiloxanos/efeitos adversos , Dimetilpolisiloxanos/uso terapêutico , Emulsificantes/química , Feminino , Gastroscopia/efeitos adversos , Humanos , Masculino , Nanoestruturas/química , Tamanho da Partícula , Polietilenoglicóis/química , Solubilidade , Viscosidade
4.
PLoS One ; 15(8): e0235229, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797117

RESUMO

With desirable physical performances of impressive actuation strain, high energy density, high degree of electromechanical coupling and high mechanical compliance, dielectric elastomer actuators (DEAs) are widely employed to actuate the soft robots. However, there are many challenges to establish the dynamic models for DEAs, such as their inherent nonlinearity, complex electromechanical coupling, and time-dependent viscoelastic behavior. Moreover, most previous studies concentrated on the planar DEAs, but the studies on DEAs with some other functional shapes are insufficient. In this paper, by investigating a conical DEA with the material of polydimethylsiloxane and considering the influence of inertia, we propose a dynamic model based on the principles of nonequilibrium thermodynamics. This dynamic model can describe the complex motion characteristics of the conical DEA. Based on the experimental data, the differential evolution algorithm is employed to identify the undetermined parameters of the developed dynamic model. The result of the model validation demonstrates the effectiveness of the model.


Assuntos
Dimetilpolisiloxanos/química , Elastômeros/química , Simulação de Dinâmica Molecular , Eletricidade , Fenômenos Mecânicos
5.
J Chromatogr A ; 1627: 461405, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823110

RESUMO

This study focused on the measurements and validity of relative distribution constants of vaporized hydrocarbons between air and polydimethylsiloxane (PDMS) using commercially available capillary columns. Capillary column gas chromatography (CCGC) measurements, using two columns containing a PDMS stationary phase with different film thicknesses, were conducted to determine the relative distribution constants of n-heptane, toluene, n-octane, p-xylene, n-nonane, and 1,2,4-trimethylbenzene between air and PDMS at 90 and 120 °C. To validate the accuracy of the relative distribution constants via CCGC, the compositions of three headspace samples containing different amounts of hydrocarbons were calculated using the relative distribution constants via CCGC and extracted amounts via PDMS solid phase microextraction (SPME) at 90 and 120 °C. It was found that calculated hydrocarbon compositions of headspace samples were comparable to true headspace hydrocarbon compositions via direct vapor analysis, with an average absolute relative error of 3.2%. Our results indicate that CCGC is an alternative method that can provide a reliable and convenient method to determine the relative distribution constants of various hydrocarbons between air and PDMS for quantitative chemical analysis of headspace.


Assuntos
Ar , Dimetilpolisiloxanos/química , Hidrocarbonetos/análise , Cromatografia de Fase Reversa , Hidrocarbonetos/química , Microextração em Fase Sólida , Volatilização
6.
Proc Natl Acad Sci U S A ; 117(29): 16743-16748, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32611809

RESUMO

Mammalian nervous systems, as natural ionic circuitries, stand out in environmental perception and sophisticated information transmission, relying on protein ionic channels and additional necessary structures. Prosperously emerged ionic regulated biomimetic nanochannels exhibit great potentialities in various application scenarios, especially signal transduction. Most reported direct current systems possess deficiencies in informational density and variability, which are superiorities of alternating current (AC) systems and necessities in bioinspired nervous signal transmission. Here, inspired by myelinated saltatory conduction, alternating electrostatic potential controlled nanofluidics are constructed with a noncontact application pattern and MXene nanosheets. Under time-variant external stimuli, ions confined in the interlaminar space obtain the capability of carriers for the AC ionic circuit. The transmitted information is accessible from typical sine to a frequency-modulated binary signal. This work demonstrates the potentiality of the bioinspired nervous signal transmission between electronics and ionic nanofluidics, which might push one step forward to the avenue of AC ionics.


Assuntos
Potenciais de Ação , Materiais Biomiméticos/química , Condutividade Elétrica , Microfluídica/métodos , Modelos Neurológicos , Nanoestruturas/química , Dimetilpolisiloxanos/química , Equipamentos e Provisões Elétricas , Transporte de Íons , Microfluídica/instrumentação
7.
Nat Commun ; 11(1): 2804, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32499540

RESUMO

Toward the development of surface-sensitive analytical techniques for biosensors and diagnostic biochip assays, a local integration of low-concentration target materials into the sensing region of interest is essential to improve the sensitivity and reliability of the devices. As a result, the dynamic process of sorting and accurate positioning the nanoparticulate biomolecules within pre-defined micro/nanostructures is critical, however, it remains a huge hurdle for the realization of practical surface-sensitive biosensors and biochips. A scalable, massive, and non-destructive trapping methodology based on dielectrophoretic forces is highly demanded for assembling nanoparticles and biosensing tools. Herein, we propose a vertical nanogap architecture with an electrode-insulator-electrode stack structure, facilitating the generation of strong dielectrophoretic forces at low voltages, to precisely capture and spatiotemporally manipulate nanoparticles and molecular assemblies, including lipid vesicles and amyloid-beta protofibrils/oligomers. Our vertical nanogap platform, allowing low-voltage nanoparticle captures on optical metasurface designs, provides new opportunities for constructing advanced surface-sensitive optoelectronic sensors.


Assuntos
Técnicas Biossensoriais , Nanopartículas/química , Nanoestruturas/química , Nanotecnologia/métodos , Bacillus subtilis , Materiais Biocompatíveis , Simulação por Computador , Dimetilpolisiloxanos/química , Eletroquímica , Eletrodos , Desenho de Equipamento , Fungos , Cinética , Lipídeos/química , Teste de Materiais , Osmose , Reprodutibilidade dos Testes
8.
PLoS One ; 15(6): e0234482, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32520967

RESUMO

Three-dimensional polydimethylsiloxane platforms were developed to mimic the extracellular matrix with blood vessels by having scaffolds with micropatterns, porous membrane and trenches. Precisely controlled physical dimensions, layouts, and topography as well as different surface chemical treatments were applied to study their influences on nasopharyngeal carcinoma cell (10-15 µm in diameter) migration in mimicked platforms over 15-hour of time-lapse imaging. By placing the pores at different distance from the edges of the trenches, pores with different trench sidewall exposures and effective sizes were generated. Pores right next to the trench sidewalls showed the highest cell traversing probability, most likely related to the larger surface contact area with cells along the sidewalls. Straight grating oriented perpendicular to trenches below the top layer increased cell traversing probability. Pore shape as well as pore size influenced the cell traversing probability and cells could not traverse through pores that were 6 µm or less in diameter, which is much smaller than the cell size. Trench depth of 15 µm could induce more cells to traverse through the porous membrane, while shallower trenches impeded cell traversing and longer time was needed for cells to traverse because 3 and 6 µm deep trenches were much smaller than cell size which required large cell deformation. Hydrophobic surface coating on the top layer and fibronectin in pores and trenches increased the cell traversing probability and reduced the pore size that cells could traverse from 8 to 6 µm, which indicated that cells could have larger deformation with certain surface coatings.


Assuntos
Materiais Biomiméticos/química , Movimento Celular , Dimetilpolisiloxanos/química , Linhagem Celular Tumoral , Matriz Extracelular/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Porosidade , Tecidos Suporte/química
9.
Chemosphere ; 258: 127179, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554002

RESUMO

Hydrophobic membranes for desalination and toxic organic pollutant removal have been fabricated using polyamide - PDMS (polydimethylsiloxane) chemistries in a one-step protocol. The curing of polyamide and PDMS are orthogonal and co-curing both networks imparts hydrophobicity to the thin film composite membranes. The membranes exhibit increased adsorption of pesticides from the feed water along with maintaining excellent salt rejection capability (97% NaCl rejection), thus giving the membranes a multifunctional character. Three toxic pesticides have been used in this study to demonstrate the viability of combining osmosis desalination technology with organic matter adsorption. The membranes also show excellent resistance to fouling by toxic pesticides (85% salt rejection vs 67% for commercial membranes in the presence of pesticides) and significantly improved chlorine tolerance (93.8% salt rejection vs 86.5% for commercial membranes after 20 h of exposure to sodium hypochlorite solution).


Assuntos
Cloro/química , Dimetilpolisiloxanos/química , Membranas Artificiais , Praguicidas/isolamento & purificação , Purificação da Água/instrumentação , Varredura Diferencial de Calorimetria , Interações Hidrofóbicas e Hidrofílicas , Nylons/química , Osmose , Espectrometria por Raios X , Termogravimetria , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos
10.
PLoS One ; 15(5): e0232081, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374763

RESUMO

The reproduction of reliable in vitro models of human skeletal muscle is made harder by the intrinsic 3D structural complexity of this tissue. Here we coupled engineered hydrogel with 3D structural cues and specific mechanical properties to derive human 3D muscle constructs ("myobundles") at the scale of single fibers, by using primary myoblasts or myoblasts derived from embryonic stem cells. To this aim, cell culture was performed in confined, laminin-coated micrometric channels obtained inside a 3D hydrogel characterized by the optimal stiffness for skeletal muscle myogenesis. Primary myoblasts cultured in our 3D culture system were able to undergo myotube differentiation and maturation, as demonstrated by the proper expression and localization of key components of the sarcomere and sarcolemma. Such approach allowed the generation of human myobundles of ~10 mm in length and ~120 µm in diameter, showing spontaneous contraction 7 days after cell seeding. Transcriptome analyses showed higher similarity between 3D myobundles and skeletal signature, compared to that found between 2D myotubes and skeletal muscle, mainly resulting from expression in 3D myobundles of categories of genes involved in skeletal muscle maturation, including extracellular matrix organization. Moreover, imaging analyses confirmed that structured 3D culture system was conducive to differentiation/maturation also when using myoblasts derived from embryonic stem cells. In conclusion, our structured 3D model is a promising tool for modelling human skeletal muscle in healthy and diseases conditions.


Assuntos
Técnicas de Cultura de Células , Fibras Musculares Esqueléticas/citologia , Músculo Esquelético/citologia , Engenharia Tecidual , Tecidos Suporte/química , Animais , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Diferenciação Celular , Células Cultivadas , Dimetilpolisiloxanos/química , Humanos , Hidrogéis/química , Teste de Materiais , Camundongos , Modelos Biológicos , Conformação Molecular , Desenvolvimento Muscular , Músculo Esquelético/fisiologia , Mioblastos/citologia , Mioblastos/fisiologia , Análise de Célula Única/instrumentação , Análise de Célula Única/métodos , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos
11.
Nat Commun ; 11(1): 2190, 2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32366850

RESUMO

Microfluidics by soft lithography has proven to be of key importance for biophysics and life science research. While being based on replicating structures of a master mold using benchtop devices, design modifications are time consuming and require sophisticated cleanroom equipment. Here, we introduce virtual fluidic channels as a flexible and robust alternative to microfluidic devices made by soft lithography. Virtual channels are liquid-bound fluidic systems that can be created in glass cuvettes and tailored in three dimensions within seconds for rheological studies on a wide size range of biological samples. We demonstrate that the liquid-liquid interface imposes a hydrodynamic stress on confined samples, and the resulting strain can be used to calculate rheological parameters from simple linear models. In proof-of-principle experiments, we perform high-throughput rheology inside a flow cytometer cuvette and show the Young's modulus of isolated cells exceeds the one of the corresponding tissue by one order of magnitude.


Assuntos
Dimetilpolisiloxanos/química , Módulo de Elasticidade/fisiologia , Técnicas Analíticas Microfluídicas/métodos , Microfluídica/métodos , Polietilenoglicóis/química , Algoritmos , Desenho de Equipamento , Citometria de Fluxo , Células HEK293 , Células HL-60 , Humanos , Hidrodinâmica , Técnicas Analíticas Microfluídicas/instrumentação , Microfluídica/instrumentação , Modelos Teóricos , Reologia , Esferoides Celulares
12.
Food Chem ; 328: 127109, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32454261

RESUMO

Feijoa is a subtropical bush of the Myrtaceae family. It has unique fruit with organoleptic properties that make it an exotic fruit. Head space solid phase microextraction (HS-SPME) with a 65 µm divinylbenzene/polydimethylsiloxane (DVB/PDMS) fiber and gas chromatography coupled to mass spectrophotometry (GC-MS) was used to study the volatile fraction of feijoa fruit cultured in Caldas, Colombia. The profile analyzed included 134 volatile organic compounds (VOCs). 127 VOCs were classified based on the functional group using the spectral and structural networks correlation analysis. Methyl, ethyl and (Z)-3-hexenyl benzoate with 50% of the volatile composition, were the main compounds. Biosynthesis of the volatilome of feijoa fruit was associated with five main metabolic pathways. This study represents the first analysis of feijoa fruit commercialized in the region. This is an innovator view in elucidation of metabolic pathways that represent the biochemistry of the aroma of this fruit.


Assuntos
Feijoa/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise , Colômbia , Dimetilpolisiloxanos/química , Feijoa/metabolismo , Análise de Alimentos/métodos , Frutas/química , Frutas/metabolismo , Odorantes/análise , Polivinil/química
13.
J Chromatogr A ; 1623: 461065, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32448558

RESUMO

We report the preparation of high performance, sputtered, polydimethylsiloxane (PDMS)-coated solid phase microextraction (SPME) fibers that show negligible carry-over and phase bleed. This process involves sputtering silicon onto silica fibers and functionalizing the resulting porous nanostructures with ultrathin films of vapor-deposited PDMS. Different thicknesses of silicon (0.25, 0.8, and 1.8 µm) and PDMS (8, 16, and 36 nm) were produced and their extraction efficiencies evaluated. The deposition of PDMS was confirmed by time-of-fight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), and contact angle goniometry on model, planar silicon substrates. These fibers were investigated using direct immersion SPME coupled with gas chromatography-mass spectrometry (GC-MS) analysis of a series of polycyclic aromatic hydrocarbons (PAHs), which are carcinogenic pollutants. The 1.8 µm thick silicon coating with 16 nm of PDMS (Si (1.8 µm)/PDMS (16 nm)) produced the best response among the combinations tested. Conditions for the extraction of PAHs with this fiber were optimized and its extraction performance was compared to that of a commercial 7 µm PDMS fiber. The linearity (1-110 µgL-1), repeatability (RSD%, n = 3) (17% ave.), and minimum detection limits (0.6-1.5 µgL-1) of the sputtered fibers were determined and found to be superior to the commercial 7 µm PDMS fiber in many respects. Carry-over and phase bleed from commercial PDMS-based SPME fibers are two of their major drawbacks, which decrease their lifetimes and usefulness. Minimal carry-over and phase bleed were observed for our sputtered PDMS-coated fibers. In particular, our fiber only shows 12% of the phase bleed of the comparable commercial fiber. In addition, it shows no carry-over for analytes with retention times greater than pyrene, and only 5% of the carry-over of the other analytes. Our fibers could be used for at least 300 injections without any significant loss of performance.


Assuntos
Dimetilpolisiloxanos/química , Silício/química , Microextração em Fase Sólida/métodos , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Espectroscopia Fotoeletrônica , Hidrocarbonetos Policíclicos Aromáticos/análise , Temperatura , Fatores de Tempo , Água/química , Poluentes Químicos da Água/análise
14.
Mikrochim Acta ; 187(3): 194, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32124079

RESUMO

A controllable approach for preparing a portable colloidal photonic crystal (CPC) array chip is presented. The approach was inspired by the confinement effect of nanoparticle self-assembly on patterned surface. Hydrophobic polydimethylsiloxane substrate with reproducible micro-region array was fabricated by soft-lithography. The substrate was employed as the patterned template for self-assembly of monodisperse polystyrene nanoparticles. The CPC units can be prepared in several minutes, and exhibit consistent reflection wavelength. By adjusting the size of polystyrene nanoparticles and the shape of micro-regions, CPC units with multiple structure, colors and geometries were obtained. The CPC array chip features fluorescence enhancement owing to the optical modulation capability of the periodic nanostructure of the self-assembled CPC. With the reflection wavelength (523 nm) of green CPC units overlapping the emission wavelength (520 nm, with excitation wavelength of 490 nm) of 6-carboxyfluorescein-labeled DNA probe, the fluorescence intensity increased more than 10-fold. For signal-amplified assay of adenosine, the concentration range of linear response was 5.0 × 10-5 mol L-1 to 1.0 × 10-3 mol L-1, and the limit of detection was 1.3 × 10-6 mol L-1. Because of the enhancement effect of photonic crystal, the fluorescence images were more readable from the CPC array chip, compared with those from the planar substrate. The chip has potential applications in multiplex determination with high-throughput via encoding strategy based on the tunable structure, color or geometric shape. Graphical abstractSchematic diagram of signal-enhanced fluorescent detection of adenosine based on the colloidal photonic crystal array chip (PDMS, polydimethylsiloxane; PS NPs, polystyrene nanoparticles; CPC, colloidal photonic crystal; GO, graphene oxide; FAM, 6-carboxyfluorescein).


Assuntos
Adenosina/análise , Técnicas Biossensoriais/métodos , Fluoresceínas/química , Corantes Fluorescentes/química , Dispositivos Lab-On-A-Chip , Coloides , Cristalização , Sondas de DNA/química , Dimetilpolisiloxanos/química , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Fótons , Espectrometria de Fluorescência , Propriedades de Superfície
15.
PLoS One ; 15(2): e0228203, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027678

RESUMO

We previously developed an in vivo site-specific transfection method using a suction device in mice; namely, a tissue suction-mediated transfection method (tissue suction method). The aim of this study was to apply the tissue suction method for cardiac gene transfer. Naked plasmid DNA (pDNA) was intravenously injected in mice, followed by direct suction on the beating heart by using a suction device made of polydimethylsiloxane. We first examined the effects of suction conditions on transgene expression and toxicity. Subsequently, we analyzed transgene-expressing cells and the transfected region of the heart. We found that heart suction induced transgene expression, and that -75 kPa and -90 kPa of suction achieved high transgene expression. In addition, the inner diameter of the suction device was correlated with transgene expression, but the pressure hold time did not change transgene expression. Although the tissue suction method at -75 kPa induced a transient increase in the serum cardiac toxicity markers at 6 h after transfection, these markers returned to normal at 24 h. The cardiac damage was also analyzed through the measurement of hypertrophic gene expression, but no significant differences were found. In addition, the cardiac function monitored by echocardiography remained normal at 11 days after transfection. Immunohistochemical analysis revealed that CD31-positive endothelial cells co-expressed the ZsGreen1-N1 reporter gene. In conclusion, the tissue suction method can achieve an efficient and safe gene transfer to the beating heart in mice.


Assuntos
Coração/fisiologia , Miocárdio/metabolismo , Transfecção/métodos , Transgenes/genética , Animais , Creatina Quinase Forma MB/sangue , Dimetilpolisiloxanos/química , Ecocardiografia , Expressão Gênica , Camundongos , Miocárdio/patologia , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Plasmídeos/administração & dosagem , Plasmídeos/genética , Plasmídeos/metabolismo , Pressão , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Transfecção/instrumentação , Troponina T/sangue
16.
J Vis Exp ; (155)2020 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-32065157

RESUMO

A traditional strain measurement sensor needs to be electrified and is susceptible to electromagnetic interference. In order to solve the fluctuations in the analog electrical signal in a traditional strain gauge operation, a new strain measurement method is presented here. It uses a photographic technique to display the strain change by amplifying the change of the pointer displacement of the mechanism. A visual polydimethylsiloxane (PDMS) lens with a focal length of 7.16 mm was added to a smartphone camera to generate a lens group acting as a microscope to capture images. It had an equivalent focal length of 5.74 mm. Acrylonitrile butadiene styrene (ABS) and nylon amplifiers were used to test the influence of different materials on the sensor performance. The production of the amplifiers and PDMS lens is based on improved 3D printing technology. The data obtained were compared with the results from finite element analysis (FEA) to verify their validity. The sensitivity of the ABS amplifier was 36.03 ± 1.34 µÎµ/µm, and the sensitivity of the nylon amplifier was 36.55 ± 0.53 µÎµ/µm.


Assuntos
Impressão Tridimensional/instrumentação , Butadienos/química , Dimetilpolisiloxanos/química , Temperatura
17.
Nat Commun ; 11(1): 535, 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31988308

RESUMO

To date, numerous biosensing platforms have been developed for assessing drug-induced cardiac toxicity by measuring the change in contractile force of cardiomyocytes. However, these low sensitivity, low-throughput, and time-consuming processes are severely limited in their real-time applications. Here, we propose a cantilever device integrated with a polydimethylsiloxane (PDMS)-encapsulated crack sensor to measure cardiac contractility. The crack sensor is chemically bonded to a PDMS thin layer that allows it to be operated very stably in culture media. The reliability of the proposed crack sensor has been improved dramatically compared to no encapsulation layer. The highly sensitive crack sensor continuously measures the cardiac contractility without changing its gauge factor for up to 26 days (>5 million heartbeats), while changes in contractile force induced by drugs are monitored using the crack sensor-integrated cantilever. Finally, experimental results are compared with those obtained via conventional optical methods to verify the feasibility of building a contraction-based drug-toxicity testing system.


Assuntos
Técnicas Biossensoriais , Dimetilpolisiloxanos/química , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Animais , Avaliação Pré-Clínica de Medicamentos/métodos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Miócitos Cardíacos/fisiologia , Quinidina/toxicidade , Ratos Sprague-Dawley , Verapamil/toxicidade
18.
Macromol Rapid Commun ; 41(5): e1900569, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31994812

RESUMO

Rapid prototyping of thin, stretchable substrates with engineered stiffness gradients at desired locations has potential impact in the robustness of skin-wearable electronics, as the gradients can inhibit cracking of interconnect and delamination of embedded electronic chips. Drop-on-demand inkjetting of thinned polydimethylsiloxane (PDMS) curing agent onto a spin-cast 80 µm-thick 20:1 (base: curing agent) PDMS substrate sets the elastic modulus of the subsequently cured film with sub-millimeter accuracy. The inkjet process creates digitally defined stiffness gradient spans as small as 100 µm for single droplets. Varying the drop density results in differences in elastic modulus of up to 80%. In jetting tests of curing agent into pure base PDMS, a continuous droplet spacing of 100 µm results in smooth lines with total widths of 1 mm and a curing agent gradient span of ≈300 µm. Release of freeform mesh elastomer microstructures by removing the uncured base after selective jetting of curing agent into pure base PDMS results in structural line width resolution down to 500 µm.


Assuntos
Dimetilpolisiloxanos/farmacologia , Elastômeros/química , Impressão Tridimensional/instrumentação , Dimetilpolisiloxanos/química , Módulo de Elasticidade , Elastômeros/farmacologia , Eletrônica/instrumentação , Propriedades de Superfície
19.
Bull Environ Contam Toxicol ; 104(1): 107-113, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31768564

RESUMO

A new analytical method for the determination of naproxen, ketoprofen, diclofenac, carbamazepine, and triclosan (TCS) in water samples by liquid chromatography is developed and validated. The method is based on the extraction of the analytes by a polydimethylsiloxane (PDMS) rod. The different parameters affecting extraction, such as the addition of salt, pH, initial volume, extraction and elution times and elution solvent, as well as the application of sonication, are studied. The results showed that the detection limits are all in the 0.1-0.3 µg L-1 range except for carbamazepine (6 µg L-1) with relative standard deviations in the range of 0.4%-9.7%. The method developed, which was validated by analysing spiked surface water samples at 10, 25 and 75 µg L-1 gave recoveries of between 84.8% and 111.2%. In the case of carbamazepine, a recovery of 99.1% was obtained at 75 µg L-1. The main advantage of the developed method is that allows high performance liquid chromatography-diode array detection, which is widely available in non-specialised laboratories, to be applied for pharmaceuticals and TCS determination in surface waters after performing a preconcentration/clean-up step with PDMS rods as it has been shown by analysing real water samples.


Assuntos
Dimetilpolisiloxanos/química , Preparações Farmacêuticas/análise , Poluentes Químicos da Água/análise , Carbamazepina , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Diclofenaco , Limite de Detecção , Reprodutibilidade dos Testes , Solventes/química , Triclosan/análise
20.
J Chromatogr A ; 1613: 460669, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-31732157

RESUMO

The development and application of non-porous and porous sorptive rods, comprised of polydimethylsiloxane-microdiamond (PDMS-MD) composites, is reported. The PDMS-MD composites were made porous using inorganic salt (NaCl and NaHCO3) particles as dissolvable templates. Materials with pore size of ~40 µm down to ~5 µm were produced. The advantages of incorporating up to ~60%microdiamond (2-4 µm) into PDMS included: (1) significant increase in the density, which saw the rods sink within the aqueous sample without addition of secondary metal or glass materials, (2) significant improvement in mechanical stability (the porous composite rods could be thermally treated multiple times before application, unlike porous PDMS), (3) increased thermal stability up to 450-500 °C with only 6% weight loss of volatile components, and (4) higher thermal conductivity, estimated to be 108% higher than for PDMS. The PDMS-MD investigated as a sorbent for extraction, followed by liquid desorption and GC-FID analysis. Recovery of the sorbent for test solutes, isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, and phenethyl acetate, was found to range from ~87% to >100, with RSD of 2.10-12.50% in synthetic wine samples. Non-porous composite rods provided similar % recoveries to a commercial sorptive device (PDMS Twister), whereas porous rods showed improved % recovery for most of the test solutes (>10-20%) when applied under similar conditions. The limits of detection (LOD) for the above solutes within the developed method ranged from 0.60 to 27.30 µg L-1). Application of the PDMS-MD-LD-GC-FID method to white wine samples demonstrated how the PDMS-MD composite material can be applied as a robust and an efficient sorptive phase for trace chemical analysis.


Assuntos
Técnicas de Química Analítica/métodos , Diamante/química , Dimetilpolisiloxanos/química , Vinho/análise , Cromatografia Gasosa , Limite de Detecção , Água/química
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