Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Dependence of cancer cell adhesion kinetics on integrin ligand surface density measured by a high-throughput label-free resonant waveguide grating biosensor.

ABSTRACT: A novel high-throughput label-free resonant waveguide grating (RWG) imager biosensor, the Epic® BenchTop (BT), was utilized to determine the dependence of cell spreading kinetics on the average surface density (v(RGD)) of integrin ligand RGD-motifs. v(RGD) was tuned over four orders of magnitude by co-adsorbing the biologically inactive PLL-g-PEG and the RGD-functionalized PLL-g-PEG-RGD synthetic copolymers from their mixed solutions onto the sensor surface. Using highly adherent human cervical tumor (HeLa) cells as a model system, cell adhesion kinetic data of unprecedented quality were obtained. Spreading kinetics were fitted with the logistic equation to obtain the spreading rate constant (r) and the maximum biosensor response (Δλmax), which is assumed to be directly proportional to the maximum spread contact area (Amax). r was found to be independent of the surface density of integrin ligands. In contrast, Δλmax increased with increasing RGD surface density until saturation at high densities. Interpreting the latter behavior with a simple kinetic mass action model, a 2D dissociation constant of 1753 ± 243 μm(-2) (corresponding to a 3D dissociation constant of ~30 μM) was obtained for the binding between RGD-specific integrins embedded in the cell membrane and PLL-g-PEG-RGD. All of these results were obtained completely noninvasively without using any labels.

SUBMITTER: Orgovan N

PROVIDER: S-EPMC3916899 | biostudies-other | 2014

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Near cut-off wavelength operation of resonant waveguide grating biosensors.

Project description:Numerical simulations and analytical calculations are performed to support the design of grating-coupled planar optical waveguides for biological sensing. Near cut-off and far from cut-off modes are investigated, and their characteristics and suitability for sensing are compared. The numerical simulations reveal the high sensitivity of the guided mode intensity near the cut-off wavelength for any refractive index change along the waveguide. Consequently, it is sufficient to monitor the intensity change of the near cut-off sensing mode, which leads to a simpler sensor design compared to those setups where the resonant wavelength shift of the guided mode is monitored with high precision. The operating wavelength and the sensitivity of the proposed device can be tuned by varying the geometrical parameters of the corrugated waveguide. These results may lead to the development of highly sensitive integrated sensors, which have a simple design and therefore are cost-effective for a wide range of applications. These numerical findings are supported with experimental results, where the cut-off sensing mode was identified.

| S-EPMC8219702 | biostudies-literature

Resonant waveguide grating based assays for colloidal aggregate detection and promiscuity characterization in natural products.

Project description:Small molecules, including natural compounds, in aqueous buffer that self-associate into colloidal aggregates is the main cause of false results in the early stage of drug discovery. Here we reported resonant waveguide grating (RWG) based assays to identify natural compound aggregation and characterize its influence on membrane receptors in living cells. We first applied a cell-free aggregation assay to determine compound critical aggregation concentration (CAC) values. Then we characterized the aggregators' influence on membrane receptors using three types of dynamic mass redistribution (DMR) assays. Results showed that colloidal aggregates may cause false activity in DMR desensitization assays; some of the false activities can be implied by the large response in DMR agonism assays and can further be identified by DMR antagonism assays. Furthermore, the aggregation mechanism was confirmed by addition of 0.025% tween-80, with cell signals attenuated and potency decreased. Finally, these observations were used for aggregate examination and promiscuity investigation of a traditional herbal medicine, Rhodiola rosea, which ultimately led to the revealing of the true target and reduced the risk of a bioactivity tracking process at the very first stage. This study highlights that the RWG based assays can be used as practical tools to distinguish between real and false hits to provide reliable results in the early stage of drug discovery.

| S-EPMC9075791 | biostudies-literature

Fiber-optic label-free biosensor for SARS-CoV-2 spike protein detection using biofunctionalized long-period fiber grating.

Project description:With COVID-19 widespread worldwide, people are still struggling to develop faster and more accurate diagnostic methods. Here we demonstrated the label-free detection of SARS-CoV-2 spike protein by employing a SARS-CoV-2 spike antibody-conjugated phase-shifted long-period fiber grating (PS-LPFG) inscribed with a CO2 laser. At a specific cladding mode, the wavelength separation (λD) between the two split dips of a PS-LPFG varies with the external refractive index, although it is virtually insensitive to ambient temperature variations. To detect SARS-CoV-2 spike protein, SARS-CoV-2 spike antibodies were immobilized on the fiber surface of the fabricated PS-LPFG functionalized through chemical modification. When exposed to SARS-CoV-2 spike protein with different concentrations, the antibody-immobilized PS-LPFG exhibited the variation of λD according to the protein concentration, which was caused by bioaffinity binding-induced local changes in the refractive index at its surface. In particular, we also confirmed the potential of our sensor for clinical application by detecting SARS-CoV-2 spike protein in virus transport medium. Moreover, our sensor could distinguish SARS-CoV-2 spike protein from those of MERS-CoV and offer efficient properties such as reusability and storage stability. Hence, we have successfully fabricated a promising optical transducer for the detection of SARS-CoV-2 spike protein, which can be unperturbed by external temperature disturbances.

| S-EPMC8363218 | biostudies-literature

A fully reconfigurable waveguide Bragg grating for programmable photonic signal processing.

Project description:Since the discovery of the Bragg's law in 1913, Bragg gratings have become important optical devices and have been extensively used in various systems. In particular, the successful inscription of a Bragg grating in a fiber core has significantly boosted its engineering applications. However, a conventional grating device is usually designed for a particular use, which limits general-purpose applications since its index modulation profile is fixed after fabrication. In this article, we propose to implement a fully reconfigurable grating, which is fast and electrically reconfigurable by field programming. The concept is verified by fabricating an integrated grating on a silicon-on-insulator platform, which is employed as a programmable signal processor to perform multiple signal processing functions including temporal differentiation, microwave time delay, and frequency identification. The availability of ultrafast and reconfigurable gratings opens new avenues for programmable optical signal processing at the speed of light.

| S-EPMC5895633 | biostudies-literature

Geometrical tuning art for entirely subwavelength grating waveguide based integrated photonics circuits.

Project description:Subwavelength grating (SWG) waveguide is an intriguing alternative to conventional optical waveguides due to the extra degree of freedom it offers in tuning a few important waveguide properties, such as dispersion and refractive index. Devices based on SWG waveguides have demonstrated impressive performances compared to conventional waveguides. However, the high loss of SWG waveguide bends jeopardizes their applications in integrated photonic circuits. In this work, we propose a geometrical tuning art, which realizes a pre-distorted refractive index profile in SWG waveguide bends. The pre-distorted refractive index profile can effectively reduce the mode mismatch and radiation loss simultaneously, thus significantly reduce the bend loss. This geometry tuning art has been numerically optimized and experimentally demonstrated in present study. Through such tuning, the average insertion loss of a 5 μm SWG waveguide bend is reduced drastically from 5.43 dB to 1.10 dB per 90° bend for quasi-TE polarization. In the future, the proposed scheme will be utilized to enhance performance of a wide range of SWG waveguide based photonics devices.

| S-EPMC4857108 | biostudies-literature

Polarization-Controlled Broad Color Palette Based on an Ultrathin One-Dimensional Resonant Grating Structure.

Project description:Highly efficient polarization-tuned structural color filters, which are based on a one- dimensional resonant aluminum grating that is integrated with a silicon nitride waveguide, are proposed and demonstrated to feature a broad color palette. For such a metallic grating structure, transmissive color filtering is only feasible for the incident transverse-magnetic (TM) polarization due to its high reflection regarding the transverse-electric (TE) case; however, polarization-tuned customized colors can be efficiently achieved by optimizing the structural parameters like the duty ratio of the metallic grating. For the fabricated color filters, the transmission peaks, which are imputed to the resonance between the incident light and the guided modes that are supported by the dielectric waveguide, provided efficiencies as high as 90% and 70% for the TM and TE polarizations, respectively, as intended. Through the tailoring of the polarization, a group of filters with different grating periods were successfully exploited to produce a broad color palette spanning the entire visible band. Lastly, a nanoscale alphabetic pattern featuring a flexible combination of colorations was practically constructed via an arrangement of horizontal and vertical gratings.

| S-EPMC5220310 | biostudies-literature

All Dielectric Transmissive Structural Multicolor Pixel Incorporating a Resonant Grating in Hydrogenated Amorphous Silicon.

Project description:All dielectric transmissive type polarization-tuned structural multicolor pixels (MCPs) are proposed and demonstrated based on a one-dimensional hydrogenated amorphous silicon (a-Si:H) grating integrated with a silicon nitride waveguide. Both bandpass and bandstop transmission filtering characteristics in the visible regime, centered at the same wavelength, have been achieved by tailoring the structural parameters including the duty ratio of the grating and the thickness of the dielectric waveguide. For the three manufactured MCPs, the transmission peak exceeds 70% for the transverse electric (TE) polarization and 90% for the transverse magnetic (TM) polarization as observed at the resonance and off-resonance wavelength, respectively. The polarization-switched transmissions are attributed to the guided mode resonance initiated by the interaction of the a-Si:H grating and the dielectric waveguide. A broad color palette covering the entire visible band was successfully realized from a suite of MCPs with varying grating pitches. The proposed structural color pixels are expected to facilitate the construction of dynamic displays, image sensors, optical data storage, security tags, and so forth.

| S-EPMC5648771 | biostudies-literature

High Throughput Label Free Measurement of Cancer Cell Adhesion Kinetics Under Hemodynamic Flow.

Project description:The kinetics of receptor-mediated cell adhesion to extracellular matrix and adherent cell monolayers plays a key role in many physiological and pathological processes including cancer metastasis. Within this process the presence of fluidic shear forces is a key regulator of binding equilibrium and kinetics of cell adhesion. Current techniques to examine the kinetics of cell adhesion are either performed in the absence of flow or are low throughput, limiting their application to pharmacological compound screening or the high throughput investigation of biological mechanisms. We developed a high throughput flow device that applies flow in a multi-well format and interfaced this system with electric cell-substrate impedance sensing (ECIS) system to allow label free detection of cell adhesion. We demonstrate that this combined system is capable of making real time measurements of cancer cell adhesion to extracellular matrix and immobilized platelets. In addition, we examined the dependence of the kinetics of binding of cancer cells on the level of shear stress and in the presence of small molecule inhibitors to adhesion-related pathways. This versatile system is broadly adaptable to the high throughput study of cell adhesion kinetics for many applications including drug screening and the investigation of the mechanisms of cancer metastasis.

| S-EPMC4728493 | biostudies-literature

Optimizing the Limit of Detection of Waveguide-Based Interferometric Biosensor Devices.

Project description:Waveguide-based photonic sensors provide a unique combination of high sensitivity, compact size and label-free, multiplexed operation. Interferometric configurations furthermore enable a simple, fixed-wavelength read-out making them particularly suitable for low-cost diagnostic and monitoring devices. Their limit of detection, i.e., the lowest analyte concentration that can be reliably observed, mainly depends on the sensors response to small refractive index changes, and the noise in the read-out system. While enhancements in the sensors response have been extensively studied, noise optimization has received much less attention. Here we show that order-of-magnitude enhancements in the limit of detection can be achieved through systematic noise reduction, and demonstrate a limit of detection of ? 10 - 8 RIU with a silicon nitride sensor operating at telecom wavelengths.

| S-EPMC6749351 | biostudies-literature

A Self-Referenced Diffraction-Based Optical Leaky Waveguide Biosensor Using Photofunctionalised Hydrogels.

Project description:We report a novel self-referenced diffraction-based leaky waveguide (LW) comprising a thin (~2 µm) film of a photofunctionalisable hydrogel created by covalent attachment of a biotinylated photocleavable linker to chitosan. Streptavidin attached to the chitosan via the photocleavable linker was selectively removed by shining 365 nm light through a photomask to create an array of strips with high and low loading of the protein, which served as sensor and reference regions respectively. The differential measurements between sensor and reference regions were used for measuring analytes (i.e., biotin protein A and IgG) while reducing environmental and non-specific effects. These include changes in temperature and sample composition caused by non-adsorbing and adsorbing species, leading to reduction in effects by ~98%, ~99%, and ~97% respectively compared to the absolute measurements. The novelty of this work lies in combining photofunctionalisable hydrogels with diffraction-based LWs for referencing. This is needed to realise the full potential of label-free optical biosensors to measure analyte concentrations in real samples that are complex mixtures, and to allow for sample analysis outside of laboratories where drifts and fluctuations in temperature are observed.

| S-EPMC7601400 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data