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1.
Cancers (Basel) ; 14(21)2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36358857

RESUMO

Natural killer (NK) cells are one of the first lines of defense against infections and malignancies. NK cell-based immunotherapies are emerging as an alternative to T cell-based immunotherapies. Preclinical and clinical studies of NK cell-based immunotherapies have given promising results in the past few decades for hematologic malignancies. Despite these achievements, NK cell-based immunotherapies have limitations, such as limited performance/low therapeutic efficiency in solid tumors, the short lifespan of NK cells, limited specificity of adoptive transfer and genetic modification, NK cell rejection by the patient's immune system, insignificant infiltration of NK cells into the tumor microenvironment (TME), and the expensive nature of the treatment. Nanotechnology could potentially assist with the activation, proliferation, near-real time imaging, and enhancement of NK cell cytotoxic activity by guiding their function, analyzing their performance in near-real time, and improving immunotherapeutic efficiency. This paper reviews the role of NK cells, their mechanism of action in killing tumor cells, and the receptors which could serve as potential targets for signaling. Specifically, we have reviewed five different areas of nanotechnology that could enhance immunotherapy efficiency: nanoparticle-assisted immunomodulation to enhance NK cell activity, nanoparticles enhancing homing of NK cells, nanoparticle delivery of RNAi to enhance NK cell activity, genetic modulation of NK cells based on nanoparticles, and nanoparticle activation of NKG2D, which is the master regulator of all NK cell responses.

2.
Biosensors (Basel) ; 12(9)2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36140122

RESUMO

Cancer is one of the major killers across the globe. According to the WHO, more than 10 million people succumbed to cancer in the year 2020 alone. The early detection of cancer is key to reducing the mortality rate. In low- and medium-income countries, the screening facilities are limited due to a scarcity of resources and equipment. Paper-based microfluidics provide a platform for a low-cost, biodegradable micro-total analysis system (µTAS) that can be used for the detection of critical biomarkers for cancer screening. This work aims to review and provide a perspective on various available paper-based methods for cancer screening. The work includes an overview of paper-based sensors, the analytes that can be detected and the detection, and readout methods used.


Assuntos
Neoplasias , Biomarcadores , Detecção Precoce de Câncer , Humanos , Microfluídica , Neoplasias/diagnóstico
3.
J Mol Graph Model ; 114: 108208, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35533632

RESUMO

Regarding the serious threat of liver cancer owing to the concealment and hard detection of liver tumors at an early stage, primary diagnosis becomes quite crucial to guarantee human health. So, in this work platinum-decorated single-walled carbon nanotubes (SWCNTs) were proposed as superior nanodevice for the detection of 1-Octen-3-ol (octenol), decane, and hexanal as liver cancer biomarkers in the exhaled breath of the patients. Herein, density functional theory (DFT) calculations have been utilized to scrutinize the structural and electronic properties of pristine and Pt-decorated SWCNTs. Obtained results showed that the gas molecules were weakly physisorbed on the pristine SWCNT with negligible charge transfer and large interaction distances. Contrariwise, after the decoration of the SWCNT with Pt metal atom, significant charges are transferred, and energy adsorption increased. The results disclosed that the energy adsorption has been enhanced, for example, energy adsorption increased two times for decane and hexanal molecules (-1.06, and -1.07 eV) upon adsorption on Pt-decorated SWCNT. Moreover, substantial charges with amount of 0.238, 0.245, and 0.223 e were transferred from octenol, decane, and hexanal to the surface, respectively. So, investigations revealed that these compounds are strongly chemisorbed on Pt-SWCNT with small interaction distances and along with the short recovery time of 1.7, 83.4, and 123 s at room temperature toward octenol, decane, and hexanal, respectively which make it a compelling nanodevice. Considering the findings, Pt-SWCNT is an excellent substrate for the sense of liver cancer biomarkers with desired recovery time and the results demonstrate its feasibility for potential application in the near future in the field of liver cancer diagnosis.


Assuntos
Neoplasias Hepáticas , Nanotubos de Carbono , Adsorção , Biomarcadores Tumorais , Humanos , Neoplasias Hepáticas/diagnóstico , Nanotubos de Carbono/química , Platina/química
4.
Sensors (Basel) ; 22(9)2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35590868

RESUMO

In this work, Green Phosphorene (GP) monolayers are studied as an electronic sensing element for detecting prostate cancer biomarkers from human urine. The adsorption of furan, C8H10 (p-xylene), and H2O on pristine GP and S- and Si-doped GP are investigated using the density functional theory (DFT) calculation. Furan and C8H10 molecules have been considered as important biomarkers of prostate cancer patients. First-principles DFT calculations are applied, and the results divulged that pristine GP could be a promising candidate for furan and C8H10 detection. It is manifested that furan and C8H10 are physisorbed on the S-, and Si-doped GP with small adsorption energy and negligible charge transfer. However, the calculations disclose that furan and C8H10 are chemically adsorbed on the pristine GP with adsorption energy of -0.73, and -1.46 eV, respectively. Moreover, we observe that a large charge is transferred from furan to the pristine GP with amount of -0.106 e. Additionally, pristine GP shows short recovery time of 1.81 s at room temperature under the visible light, which make it a reusable sensor device. Overall, our findings propose that the pristine GP sensor is a remarkable candidate for sensing of furan and other biomarkers of prostate cancer in the urine of patients.


Assuntos
Técnicas Biossensoriais , Neoplasias da Próstata , Biomarcadores , Furanos , Humanos , Masculino , Xilenos
5.
ACS Omega ; 6(7): 4696-4707, 2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33644577

RESUMO

In the present work, we report highly sensitive and selective nanosensors constructed with metal-decorated graphene-like BC6N employing nonequilibrium Green's function (NEGF) formalism combined by density functional theory (DFT) toward multiple inorganic and sulfur-containing gas molecules (NO, NO2, NH3, CO, CO2, H2S, and SO2) as disease biomarkers from human breath. Monolayer sheets of pristine BC6N and Pd-decorated BC6N were evaluated for their gas adsorption properties, electronic property changes, sensitivity, and selectivity toward disease biomarkers. The pristine BC6N nanosheets exhibited sharp drops in the bandgap when interacted with gases such as NO2 while barely affected by other gases. However, the nanosecond recovery time and low adsorption energies limit the gas sensing applications of the pristine BC6N sheet. On the other hand, the Pd-decorated BC6N-based sensor underwent a semiconductor to metal transition upon the adsorption of NO x gas molecules. The conductance change of the sensor's material in terms of I-V characteristics revealed that the Pd-decorated BC6N sensor is highly sensitive (98.6-134%) and selective (12.3-74.4 times) toward NO x gas molecules with a recovery time of 270 s under UV radiation at 498 K while weakly interacting with interfering gases in exhaled breath such as CO2 and H2O. The gas adsorption behavior suggests that metal-decorated BC6N sensors are excellent candidates for analyzing pulmonary disease and cardiovascular biomarkers, among other ailments of the stomach, kidney, and intestine.

6.
ACS Omega ; 6(4): 2450-2461, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33553863

RESUMO

MXenes, two-dimensional (2D) transition metal carbides and nitrides, have been arousing interest lately in the field of gas sensing thanks to their remarkable features such as graphene-like morphology, metal-comparable conductivity, large surface-to-volume ratio, mechanical flexibility, and great hydrophilic surface functionalities. With tunable etching and synthesis methods, the morphology of the MXenes, the interlayer structures, and functional group ratios on their surfaces were effectively harnessed, enhancing the efficiency of MXene-based gas-sensing devices. MXenes also efficiently form nanohybrids with other nanomaterials, as a practical approach to revamp the sensing performance of the MXene sensors. This Mini-Review summarizes the recent experimental and theoretical reports on the gas-sensing applications of MXenes and their hybrids. It also discusses the challenges and provides probable solutions that can accentuate the future perspective of MXenes in gas sensors.

7.
Int J Mol Sci ; 21(15)2020 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-32717853

RESUMO

As SARS-CoV-2 is spreading rapidly around the globe, adopting proper actions for confronting and protecting against this virus is an essential and unmet task. Reactive oxygen species (ROS) promoting molecules such as peroxides are detrimental to many viruses, including coronaviruses. In this paper, metal decorated single-wall carbon nanotubes (SWCNTs) were evaluated for hydrogen peroxide (H2O2) adsorption for potential use for designing viral inactivation surfaces. We employed first-principles methods based on the density functional theory (DFT) to investigate the capture of an individual H2O2 molecule on pristine and metal (Pt, Pd, Ni, Cu, Rh, or Ru) decorated SWCNTs. Although the single H2O2 molecule is weakly physisorbed on pristine SWCNT, a significant improvement on its adsorption energy was found by utilizing metal functionalized SWCNT as the adsorbent. It was revealed that Rh-SWCNT and Ru-SWCNT systems demonstrate outstanding performance for H2O2 adsorption. Furthermore, we discovered through calculations that Pt- and Cu-decorated SWNCT-H2O2 systems show high potential for filters for virus removal and inactivation with a very long shelf-life (2.2 × 1012 and 1.9 × 108 years, respectively). The strong adsorption of metal decorated SWCNTs and the long shelf-life of these nanomaterials suggest they are exceptional candidates for designing personal protection equipment against viruses.


Assuntos
Betacoronavirus/efeitos dos fármacos , Desinfetantes/farmacologia , Peróxido de Hidrogênio/análise , Nanotubos de Carbono/química , Adsorção , COVID-19 , Infecções por Coronavirus/prevenção & controle , Teoria da Densidade Funcional , Desinfetantes/química , Estabilidade de Medicamentos , Humanos , Ferro/química , Ferro/farmacologia , Pandemias/prevenção & controle , Equipamento de Proteção Individual , Platina/química , Platina/farmacologia , Pneumonia Viral/prevenção & controle , Ródio/química , Ródio/farmacologia , Rutênio/química , Rutênio/farmacologia , SARS-CoV-2 , Inativação de Vírus
8.
Nanotechnology ; 31(2): 025708, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31609687

RESUMO

In this paper, we present high-performance and versatile inkjet-printed paper photo-actuators based on two-dimensional (2D) nanomaterials. As a rapid fabrication method, inkjet printing of 2D materials is used to promptly fabricate photo-actuators in a bi-layer paper/polymer structure. Water-based and biocompatible inks based on graphene and molybdenum disulfide are developed based on liquid phase exfoliation and differential centrifugation technique. It is shown that incorporation of 2D materials with inkjet printing techniques and liquid phase exfoliation can lead to rapid fabrication of photo-actuators with huge opto-mechanical energy release and versatility with a broad range of applications due to specific design and methods presented in this paper.

9.
Lab Chip ; 19(11): 1899-1915, 2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31049504

RESUMO

In this paper, we report the development of the nanotube-CTC-chip for isolation of tumor-derived epithelial cells (circulating tumor cells, CTCs) from peripheral blood, with high purity, by exploiting the physical mechanisms of preferential adherence of CTCs on a nanotube surface. The nanotube-CTC-chip is a new 76-element microarray technology that combines carbon nanotube surfaces with microarray batch manufacturing techniques for the capture and isolation of tumor-derived epithelial cells. Using a combination of red blood cell (RBC) lysis and preferential adherence, we demonstrate the capture and enrichment of CTCs with a 5-log reduction of contaminating WBCs. EpCAM negative MDA-MB-231/luciferase-2A-green fluorescent protein (GFP) cells were spiked in the blood of wild mice and enriched using an RBC lysis protocol. The enriched samples were then processed using the nanotube-CTC-chip for preferential CTC adherence on the nanosurface and counting the GFP cells yielded anywhere from 89% to 100% capture from the droplets. Electron microscopy (EM) studies showed focal adhesion with filaments from the cell body to the nanotube surface. We compared the nanotube preferential adherence to collagen adhesion matrix (CAM) scaffolding, reported as a viable strategy for CTC capture in patients. The CAM scaffolding on the device surface yielded 50% adherence with 100% tracking of cancer cells (adhered vs. non-adhered) versus carbon nanotubes with >90% adherence and 100% tracking for the same protocol. The nanotube-CTC-chip successfully captured CTCs in the peripheral blood of breast cancer patients (stage 1-4) with a range of 4-238 CTCs per 8.5 ml blood or 0.5-28 CTCs per ml. CTCs (based on CK8/18, Her2, EGFR) were successfully identified in 7/7 breast cancer patients, and no CTCs were captured in healthy controls (n = 2). CTC enumeration based on multiple markers using the nanotube-CTC-chip enables dynamic views of metastatic progression and could potentially have predictive capabilities for diagnosis and treatment response.


Assuntos
Neoplasias da Mama/patologia , Adesão Celular , Biópsia Líquida/instrumentação , Nanotubos de Carbono/química , Células Neoplásicas Circulantes/patologia , Análise Serial de Tecidos/instrumentação , Linhagem Celular Tumoral , Células Epiteliais/patologia , Humanos , Invasividade Neoplásica , Metástase Neoplásica , Análise de Célula Única , Propriedades de Superfície
10.
Sci Rep ; 8(1): 4296, 2018 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-29511291

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

11.
Sci Rep ; 8(1): 64, 2018 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-29311609

RESUMO

We describe the coupled straintronic-photothermic effect where coupling between bandgap of the 2D layered semiconductor under localized strains, optical absorption and the photo-thermal effect results in a large chromatic mechanical response in TMD-nanocomposites. Under the irradiation of visible light (405 nm to 808 nm), such locally strained atomic thin films based on 2H-MoS2 embedded in an elastomer such as poly (dimethyl) siloxane matrix exhibited a large amplitude of photo-thermal actuation compared to their unstrained counterparts. Moreover, the locally strain engineered nanocomposites showed tunable mechanical response giving rise to higher mechanical stress at lower photon energies. Scanning photoluminescence spectroscopy revealed a change in bandgap of 30 meV between regions encompassing highly strained compared to the unstrained few layers. For 1.6% change in the bandgap, the macroscopic photo-thermal response increased by a factor of two. Millimeter scale bending actuators based on the locally strained 2H-MoS2 resulted in significantly enhanced photo-thermal actuation displacements compared to their unstrained counterparts at lower photon energies and operated up to 30 Hz. Almost 1 mN photo-activated force was obtained at 50 mW and provided long-term stability. This study demonstrates a new mechanism in TMD-nanocomposites that would be useful for developing broad range of transducers.

12.
Sci Rep ; 8(1): 275, 2018 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-29305573

RESUMO

A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.

13.
Sci Rep ; 7(1): 14599, 2017 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-29097706

RESUMO

The ability to convert electrical energy into mechanical motion is of significant interest in many energy conversion technologies. Here, we demonstrate the first liquid phase exfoliated WS2-Nafion nanocomposite based electro-mechanical actuators. Highly exfoliated layers of WS2 mixed with Nafion solution, solution cast and doped with Li+ was studied as electromechanical actuators. Resonant Raman spectroscopy, X-ray photo-electron-spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, and AC impedance spectroscopy were used to study the structure, photoluminescence, water uptake, mechanical and electromechanical actuation properties of the exfoliated nanocomposites. A 114% increase in elastic modulus (dry condition), 160% increase in proton conductivity, 300% increase in water uptake, cyclic strain amplitudes of ~0.15% for 0.1 Hz excitation frequency, tip displacements greater than nanotube-Nafion and graphene-Nafion actuators and continuous operation for more than 5 hours is observed for TMD-Nafion actuators. The mechanism behind the increase in water uptake is a result of oxygen atoms occupying the vacancies in the hydrophilic exfoliated flakes and subsequently bonding with water, not possible in Nafion composites based on carbon nanotube and graphene.

14.
Biosensors (Basel) ; 7(2)2017 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-28420169

RESUMO

This study demonstrates the rapid and label-free detection of Interleukin-6 (IL-6) using carbon nanotube micro-arrays with aptamer as the molecular recognition element. Single wall carbon nanotubes micro-arrays biosensors were manufactured using photo-lithography, metal deposition, and etching techniques. Nanotube biosensors were functionalized with 1-Pyrenebutanoic Acid Succinimidyl Ester (PASE) conjugated IL-6 aptamers. Real time response of the sensor conductance was monitored with increasing concentration of IL-6 (1 pg/mL to 10 ng/mL), exposure to the sensing surface in buffer solution, and clinically relevant spiked blood samples. Non-specific Bovine Serum Albumin (BSA), PBS samples, and anti-IgG functionalized devices gave similar signatures in the real time conductance versus time experiments with no significant change in sensor signal. Exposure of the aptamer functionalized nanotube surface to IL-6 decreased the conductance with increasing concentration of IL-6. Experiments based on field effect transistor arrays suggested shift in drain current versus gate voltage for 1 pg and 1 ng of IL-6 exposure. Non-specific BSA did not produce any appreciable shift in the Ids versus Vg suggesting specific interactions of IL-6 on PASE conjugated aptamer surface gave rise to the change in electrical signal. Both Z axis and phase image in an Atomic Force Microscope (AFM) suggested unambiguous molecular interaction of the IL-6 on the nanotube-aptamer surface at 1 pg/mL concentration. The concentration of 1 pg falls below the diagnostic gray zone for cancer (2.3 pg-4 ng/mL), which is an indicator of early stage cancer. Thus, nanotube micro-arrays could potentially be developed for creating multiplexed assays involving cancer biomarker proteins and possibly circulating tumor cells all in a single assay using PASE functionalization protocol.


Assuntos
Aptâmeros de Nucleotídeos/química , Interleucina-6/sangue , Nanotubos de Carbono/química , Análise Serial de Proteínas/métodos , Animais , Biomarcadores Tumorais/sangue , Bovinos , Feminino , Humanos , Masculino , Neoplasias/sangue , Pirenos/química , Sensibilidade e Especificidade , Soroalbumina Bovina/química , Succinimidas/química
15.
Open Access Med Stat ; 2016(6): 21-29, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27942497

RESUMO

The development of biosensors that produce time series data will facilitate improvements in biomedical diagnostics and in personalized medicine. The time series produced by these devices often contains characteristic features arising from biochemical interactions between the sample and the sensor. To use such characteristic features for determining sample class, similarity-based classifiers can be utilized. However, the construction of such classifiers is complicated by the variability in the time domains of such series that renders the traditional distance metrics such as Euclidean distance ineffective in distinguishing between biological variance and time domain variance. The dynamic time warping (DTW) algorithm is a sequence alignment algorithm that can be used to align two or more series to facilitate quantifying similarity. In this article, we evaluated the performance of DTW distance-based similarity classifiers for classifying time series that mimics electrical signals produced by nanotube biosensors. Simulation studies demonstrated the positive performance of such classifiers in discriminating between time series containing characteristic features that are obscured by noise in the intensity and time domains. We then applied a DTW distance-based k-nearest neighbors classifier to distinguish the presence/absence of mesenchymal biomarker in cancer cells in buffy coats in a blinded test. Using a train-test approach, we find that the classifier had high sensitivity (90.9%) and specificity (81.8%) in differentiating between EpCAM-positive MCF7 cells spiked in buffy coats and those in plain buffy coats.

16.
Sci Rep ; 6: 34831, 2016 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-27713550

RESUMO

The ability to convert photons of different wavelengths directly into mechanical motion is of significant interest in many energy conversion and reconfigurable technologies. Here, using few layer 2H-MoS2 nanosheets, layer by layer process of nanocomposite fabrication, and strain engineering, we demonstrate a reversible and chromatic mechanical response in MoS2-nanocomposites between 405 nm to 808 nm with large stress release. The chromatic mechanical response originates from the d orbitals and is related to the strength of the direct exciton resonance A and B of the few layer 2H-MoS2 affecting optical absorption and subsequent mechanical response of the nanocomposite. Applying uniaxial tensile strains to the semiconducting few-layer 2H-MoS2 crystals in the nanocomposite resulted in spatially varying energy levels inside the nanocomposite that enhanced the broadband optical absorption up to 2.3 eV and subsequent mechanical response. The unique photomechanical response in 2H-MoS2 based nanocomposites is a result of the rich d electron physics not available to nanocomposites based on sp bonded graphene and carbon nanotubes, as well as nanocomposite based on metallic nanoparticles. The reversible strain dependent optical absorption suggest applications in broad range of energy conversion technologies that is not achievable using conventional thin film semiconductors.

17.
Nanotechnology ; 27(44): 44LT03, 2016 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-27680886

RESUMO

We demonstrate the rapid and label-free capture of breast cancer cells spiked in blood using nanotube-antibody micro-arrays. 76-element single wall carbon nanotube arrays were manufactured using photo-lithography, metal deposition, and etching techniques. Anti-epithelial cell adhesion molecule (anti-EpCAM), Anti-human epithelial growth factor receptor 2 (anti-Her2) and non-specific IgG antibodies were functionalized to the surface of the nanotube devices using 1-pyrene-butanoic acid succinimidyl ester. Following device functionalization, blood spiked with SKBR3, MCF7 and MCF10A cells (100/1000 cells per 5 µl per device, 170 elements totaling 0.85 ml of whole blood) were adsorbed on to the nanotube device arrays. Electrical signatures were recorded from each device to screen the samples for differences in interaction (specific or non-specific) between samples and devices. A zone classification scheme enabled the classification of all 170 elements in a single map. A kernel-based statistical classifier for the 'liquid biopsy' was developed to create a predictive model based on dynamic time warping series to classify device electrical signals that corresponded to plain blood (control) or SKBR3 spiked blood (case) on anti-Her2 functionalized devices with ∼90% sensitivity, and 90% specificity in capture of 1000 SKBR3 breast cancer cells in blood using anti-Her2 functionalized devices. Screened devices that gave positive electrical signatures were confirmed using optical/confocal microscopy to hold spiked cancer cells. Confocal microscopic analysis of devices that were classified to hold spiked blood based on their electrical signatures confirmed the presence of cancer cells through staining for DAPI (nuclei), cytokeratin (cancer cells) and CD45 (hematologic cells) with single cell sensitivity. We report 55%-100% cancer cell capture yield depending on the active device area for blood adsorption with mean of 62% (∼12 500 captured off 20 000 spiked cells in 0.1 ml blood) in this first nanotube-CTC chip study.

18.
Nanotechnology ; 27(13): 13LT02, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26901310

RESUMO

We demonstrate the rapid and label-free capture of breast cancer cells spiked in buffy coats using nanotube-antibody micro-arrays. Single wall carbon nanotube arrays were manufactured using photo-lithography, metal deposition, and etching techniques. Anti-epithelial cell adhesion molecule (EpCAM) antibodies were functionalized to the surface of the nanotube devices using 1-pyrene-butanoic acid succinimidyl ester functionalization method. Following functionalization, plain buffy coat and MCF7 cell spiked buffy coats were adsorbed on to the nanotube device and electrical signatures were recorded for differences in interaction between samples. A statistical classifier for the 'liquid biopsy' was developed to create a predictive model based on dynamic time warping to classify device electrical signals that corresponded to plain (control) or spiked buffy coats (case). In training test, the device electrical signals originating from buffy versus spiked buffy samples were classified with ∼100% sensitivity, ∼91% specificity and ∼96% accuracy. In the blinded test, the signals were classified with ∼91% sensitivity, ∼82% specificity and ∼86% accuracy. A heatmap was generated to visually capture the relationship between electrical signatures and the sample condition. Confocal microscopic analysis of devices that were classified as spiked buffy coats based on their electrical signatures confirmed the presence of cancer cells, their attachment to the device and overexpression of EpCAM receptors. The cell numbers were counted to be ∼1-17 cells per 5 µl per device suggesting single cell sensitivity in spiked buffy coats that is scalable to higher volumes using the micro-arrays.


Assuntos
Anticorpos/metabolismo , Neoplasias da Mama/patologia , Separação Celular/métodos , Análise Serial de Proteínas/métodos , Linhagem Celular Tumoral , Feminino , Humanos , Células MCF-7 , Nanotubos de Carbono/química , Coloração e Rotulagem
19.
Nanotechnology ; 26(26): 261001, 2015 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-26056744

RESUMO

New molybdenum disulfide (MoS2)-based polymer composites and their reversible mechanical responses to light are presented, suggesting MoS2 as an excellent candidate for energy conversion. Homogeneous mixtures of MoS2/polydimethylsiloxane (PDMS) nanocomposites (0.1-5 wt.%) were prepared and their near infrared (NIR) mechanical responses studied with increasing pre-strains. NIR triggering resulted in an extraordinary change in stress levels of the actuators by ~490 times. Actuation responses of MoS2 polymer composites depended on applied pre-strains. At lower levels of pre-strains (3-9%) the actuators showed reversible expansion while at high levels (15-50%), the actuators exhibited reversible contraction. An opto-mechanical conversion (η)∼0.5-3 MPa W(-1) was calculated. The ratio of maximum stress due to photo-actuation (σmax) at 50% strain to the minimum stress due to photo-actuation (σmin) at 3% strain was found to be ∼315-322% for MoS2 actuators (for 0.1 to 5 wt.% additive), greater than single layer graphene (∼188%) and multi-wall nanotube (∼172%) photo-mechanical actuators. Unlike other photomechanical actuators, the MoS2 actuators exhibited strong light-matter interactions and an unambiguous increase in amplitude of photomechanical response with increasing strains. A power law dependence of σmax/σmin on strains with a scaling exponent of ß = 0.87-1.32 was observed, suggesting that the origin of photomechanical response is intertwined dynamically with the molecular mechanisms at play in MoS2 actuators.

20.
Nanotechnology ; 25(35): 355501, 2014 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-25116197

RESUMO

Elastomeric composites based on nanotube liquid crystals (LCs) that preserve the internal orientation of nanotubes could lead to anisotropic physical properties and flexible energy conversion. Using a simple vacuum filtration technique of fabricating nanotube LC films and utilizing a transfer process to poly (dimethyl) siloxane wherein the LC arrangement is preserved, here we demonstrate unique and reversible photomechanical response of this layered composite to excitation by near infra-red (NIR) light at ultra-low nanotube mass fractions. On excitation by NIR photons, with application of small or large pre-strains, significant expansion or contraction of the sample occurs, respectively, that is continuously reversible and three orders of magnitude larger than in pristine polymer. Schlieren textures were noted in these LC composites confirming long range macroscopic nematic order of nanotubes within the composites. Order parameters of LC films ranged from S(optical) = 0.51-0.58 from dichroic measurements. Film concentrations, elastic modulus and photomechanical stress were all seen to be related to the nematic order parameter. For the same nanotube concentration, the photomechanical stress was almost three times larger for the self-assembled LC nanotube actuator compared to actuator based on randomly oriented carbon nanotubes. Investigation into the kinetics of photomechanical actuation showed variation in stretching exponent ß with pre-strains, concentration and orientation of nanotubes. Maximum photomechanical stress of ∼ 0.5 MPa W(-1) and energy conversion of ∼ 0.0045% was achieved for these layered composites. The combination of properties, namely, optical anisotropy, reversible mechanical response to NIR excitation and flexible energy conversion all in one system accompanied with low cost makes nanotube LC elastomers important for soft photochromic actuation, energy conversion and photo-origami applications.

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