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label free biomolecular interaction

Sibaprasad Maity, Ekaterina Viazovkina, Alexander Gall, Yuri Lyubchenko
Probing of biomolecular complexes by single-molecule force spectroscopy (SMFS) methods including AFM requires proper and suitable coupling methods for immobilization of biomolecules onto the AFM tip and the surface. The use of flexible tethers for the coupling process has dual advantages. First, they allow the specific immobilization of interacting molecules, and second, their flexibility facilitates the proper orientation of the interacting partners. Recently, we developed an approach termed Flexible Nano Array (FNA) in which interacting partners are located on the same polymeric FNA molecule separated by a flexible segment with a defined length...
2016: Journal of Nature and Science
Hui Wang, Ke Ma, Bin Xu, Wenjing Tian
Aggregation-induced emission (AIE) probes have shown great potential applications in fluorescent sensing of biomolecules, and the integration of AIE probe and graphene oxide (GO) attracts intense interest in developing new tools for label-free and "turn-on" fluorescent biomolecular analysis. Herein, an ultrasensitive label-free and "turn-on" DNA sensing is realized by tuning the supramolecular interactions of AIE probe and GO with DNA. The investigation of supramolecular interactions of AIE probes and GO with DNA demonstrate that AIE probe with short alkyl chains substitute shows highest binding affinity with DNA strand, and GO with low oxidation degree possesses strong binding interactions to ssDNA and the highest fluorescence quenching efficiency...
September 26, 2016: Small
Shu-Cheng Lo, En-Hung Lin, Pei-Kuen Wei, Wan-Shao Tsai
In this study, we demonstrate a compact imaging spectroscopic system for high-throughput detection of biomolecular interactions on plasmonic chips, based on a curved grating as the key element of light diffraction and light focusing. Both the curved grating and the plasmonic chips are fabricated on flexible plastic substrates using a gas-assisted thermal-embossing method. A fiber-coupled broadband light source and a camera are included in the system. Spectral resolution within 1 nm is achieved in sensing environmental index solutions and protein bindings...
October 17, 2016: Analyst
Qinglan Huang, Jessie Peh, Paul J Hergenrother, Brian T Cunningham
We report the design, fabrication, and testing of a photonic crystal (PC) biosensor structure that incorporates a porous high refractive index TiO2 dielectric film that enables immobilization of capture proteins within an enhanced surface-area volume that spatially overlaps with the regions of resonant electromagnetic fields where biomolecular binding can produce the greatest shifts in photonic crystal resonant wavelength. Despite the nanoscale porosity of the sensor structure, the PC slab exhibits narrowband and high efficiency resonant reflection, enabling the structure to serve as a wavelength-tunable element of an external cavity laser...
August 15, 2016: Applied Physics Letters
Huan Wang, Xiaomei Wang, Jue Wang, Weiling Fu, Chunyan Yao
The detection of tumor markers is very important in early cancer diagnosis; however, tumor markers are usually present at very low concentrations, especially in the early stages of tumor development. Surface plasmon resonance (SPR) is widely used to detect biomolecular interactions; it has inherent advantages of being high-throughput, real-time, and label-free technique. However, its sensitivity needs essential improvement for practical applications. In this study, we developed a signal amplification strategy using antibody-quantum dot (QD) conjugates for the sensitive and quantitative detection of α-fetoprotein (AFP), carcinoembryonic antigen (CEA) and cytokeratin fragment 21-1 (CYFRA 21-1) in clinical samples...
2016: Scientific Reports
D Verzijl, T Riedl, P W H I Parren, A F Gerritsen
Biolayer interferometry (BLI) is a well-established optical label-free technique to study biomolecular interactions. Here we describe for the first time a cell-based BLI (cBLI) application that allows label-free real-time monitoring of signal transduction in living cells. Human A431 epidermoid carcinoma cells were captured onto collagen-coated biosensors and serum-starved, followed by exposure to agonistic compounds targeting various receptors, while recording the cBLI signal. Stimulation of the epidermal growth factor receptor (EGFR) with EGF, the β2-adrenoceptor with dopamine, or the hepatocyte growth factor receptor (HGFR/c-MET) with an agonistic antibody resulted in distinct cBLI signal patterns...
August 28, 2016: Biosensors & Bioelectronics
M F M Fathil, M K Md Arshad, A R Ruslinda, M Nuzaihan M N, Subash C B Gopinath, R Adzhri, U Hashim
A real-time ability to interpret the interaction between targeted biomolecules and the surface of semiconductors (metal transducers) into readable electrical signals, without biomolecular modification involving fluorescence dyes, redox enzymes, and radioactive labels, created by label-free biosensors has been extensively researched. Field-effect transistor (FET)- and capacitor-based biosensors are among the diverse electrical charge biosensing architectures that have drawn much attention for having charge transduction; thus, enabling the early and rapid diagnosis of the appropriate cardiac biomarkers at lower concentrations...
September 7, 2016: Analytica Chimica Acta
Otto K Kari, Tatu Rojalin, Stefano Salmaso, Michela Barattin, Hanna Jarva, Seppo Meri, Marjo Yliperttula, Tapani Viitala, Arto Urtti
When nanocarriers are administered into the blood circulation, a complex biomolecular layer known as the "protein corona" associates with their surface. Although the drivers of corona formation are not known, it is widely accepted that this layer mediates biological interactions of the nanocarrier with its surroundings. Label-free optical methods can be used to study protein corona formation without interfering with its dynamics. We demonstrate the proof-of-concept for a multi-parametric surface plasmon resonance (MP-SPR) technique in monitoring the formation of a protein corona on surface-immobilized liposomes subjected to flowing 100 % human serum...
August 4, 2016: Drug Delivery and Translational Research
Gen He, Jie Li, Haina Ci, Chuanmin Qi, Xuefeng Guo
Herein, we report label-free detection of single-molecule DNA hybridization dynamics with single-base resolution. By using an electronic circuit based on point-decorated silicon nanowires as electrical probes, we directly record the folding/unfolding process of individual hairpin DNAs with sufficiently high signal-to-noise ratio and bandwidth. These measurements reveal two-level current oscillations with strong temperature dependence, enabling us to determine the thermodynamic and kinetic properties of hairpin DNA hybridization...
July 25, 2016: Angewandte Chemie
Dina Lakayan, Rob Haselberg, Wilfried M A Niessen, Govert W Somsen, Jeroen Kool
Surface plasmon resonance (SPR) is an optical technique that measures biomolecular interactions. Stand-alone SPR cannot distinguish different binding components present in one sample. Moreover, sample matrix components may show non-specific binding to the sensor surface, leading to detection interferences. This study describes the development of coupled size-exclusion chromatography (SEC) SPR sensing for the separation of sample components prior to their on-line bio-interaction analysis. A heterogeneous polyclonal human serum albumin antibody (anti-HSA) sample, which was characterized by proteomics analysis, was used as test sample...
June 24, 2016: Journal of Chromatography. A
M Lucia Bianconi
Isothermal titration calorimetry (ITC) is a label-free technique that allows the direct determination of the heat absorbed or released in a reaction. Frequently used to determining binding parameters in biomolecular interactions, it is very useful to address enzyme-catalyzed reactions as both kinetic and thermodynamic parameters can be obtained. Since calorimetry measures the total heat effects of a reaction, it is important to consider the contribution of the heat of protonation/deprotonation that is possibly taking place...
2016: Methods in Enzymology
Rahim Esfandyarpour, Lu Yang, Zahra Koochak, James S Harris, Ronald W Davis
The improvements in our ability to sequence and genotype DNA have opened up numerous avenues in the understanding of human biology and medicine with various applications, especially in medical diagnostics. But the realization of a label free, real time, high-throughput and low cost biosensing platforms to detect molecular interactions with a high level of sensitivity has been yet stunted due to two factors: one, slow binding kinetics caused by the lack of probe molecules on the sensors and two, limited mass transport due to the planar structure (two-dimensional) of the current biosensors...
February 2016: Biomedical Microdevices
Stephen Vance, Effat Zeidan, Vincent C Henrich, Marinella G Sandros
Sensitive and selective methods for the detection of human growth hormone (hGH) over a wide range of concentrations (high levels of 50-100 ng ml(-) (1) and minimum levels of 0.03 ng ml(-) (1)) in circulating blood are essential as variable levels may indicate altered physiology. For example, growth disorders occurring in childhood can be diagnosed by measuring levels of hGH in blood. Also, the misuse of recombinant hGH in sports not only poses an ethical issue it also presents serious health threats to the abuser...
2016: Journal of Visualized Experiments: JoVE
Abhinav Kumar, Elif Melis Bicer, Anna Babin Morgan, Paul E Pfeffer, Marco Monopoli, Kenneth A Dawson, Jonny Eriksson, Katarina Edwards, Steven Lynham, Matthew Arno, Annelie F Behndig, Anders Blomberg, Graham Somers, Dave Hassall, Lea Ann Dailey, Ben Forbes, Ian S Mudway
UNLABELLED: When inhaled nanoparticles deposit in the lungs, they transit through respiratory tract lining fluid (RTLF) acquiring a biomolecular corona reflecting the interaction of the RTLF with the nanomaterial surface. Label-free snapshot proteomics was used to generate semi-quantitative profiles of corona proteins formed around silica (SiO2) and poly(vinyl) acetate (PVAc) nanoparticles in RTLF, the latter employed as an archetype drug delivery vehicle. The evolved PVAc corona was significantly enriched compared to that observed on SiO2 nanoparticles (698 vs...
May 2016: Nanomedicine: Nanotechnology, Biology, and Medicine
Purushottam Babu Tiwari, Aykut Üren, Jin He, Yesim Darici, Xuewen Wang
Surface plasmon resonance (SPR) is a widely used, affinity based, label-free biophysical technique to investigate biomolecular interactions. The extraction of rate constants requires accurate identification of the particular binding model. The bivalent analyte model involves coupled non-linear differential equations. No clear procedure to identify the bivalent analyte mechanism has been established. In this report, we propose a unique signature for the bivalent analyte model. This signature can be used to distinguish the bivalent analyte model from other biphasic models...
October 2015: Review of Scientific Instruments
Björn Agnarsson, Anders Lundgren, Anders Gunnarsson, Michael Rabe, Angelika Kunze, Mokhtar Mapar, Lisa Simonsson, Marta Bally, Vladimir P Zhdanov, Fredrik Höök
Advancement in the understanding of biomolecular interactions has benefited greatly from the development of surface-sensitive bioanalytical sensors. To further increase their broad impact, significant efforts are presently being made to enable label-free and specific biomolecule detection with high sensitivity, allowing for quantitative interpretation and general applicability at low cost. In this work, we have addressed this challenge by developing a waveguide chip consisting of a flat silica core embedded in a symmetric organic cladding with a refractive index matching that of water...
December 22, 2015: ACS Nano
Miriam Jauset Rubio, Markéta Svobodová, Teresa Mairal, Ciara K O'Sullivan
Surface plasmon resonance imaging (SPRi) is a label-free detection method that offers a suitable and reliable platform for the real time monitoring of biomolecular interactions. In the work reported here, SPRi was used to evaluate the affinity and specificity of three different aptamers selected against the Lup an 1 anaphylactic allergen β-conglutin (β-conglutin binding aptamers I and II (β-CBA I and β-CBA II)), as well as an 11-mer truncated version of β-CBA I. Thiol modified aptamers were immobilised on a gold substrate through a self-assembling process and the use of different blocking strategies to prevent non-specific binding were evaluated...
March 15, 2016: Methods: a Companion to Methods in Enzymology
Shuo Wang, Gregory M K Poon, W David Wilson
Biosensor-surface plasmon resonance (SPR) technology has emerged as a powerful label-free approach for the study of nucleic acid interactions in real time. The method provides simultaneous equilibrium and kinetic characterization for biomolecular interactions with low sample requirements and without the need for external probes. A detailed and practical guide for protein-DNA interaction analyses using biosensor-SPR methods is presented. Details of SPR technology and basic fundamentals are described with recommendations on the preparation of the SPR instrument, sensor chips and samples, experimental design, quantitative and qualitative data analyses and presentation...
2015: Methods in Molecular Biology
Yun Liu, Shimeng Chen, Qiang Liu, Jean-François Masson, Wei Peng
A compact multi-channel surface plasmon resonance (SPR) biosensor is demonstrated based on a tablet as the measurement platform. The SPR biosensor employs a bundle of fiber-optic SPR sensors as the multiplexed sensing elements that are illuminated by a light-emitting diode (LED) plane light source and detected by a cordless camera. The multi-channel SPR biosensor was based on optical fiber components for precise, label-free and high-throughput detection without the use of complex, specialized or fragile instrumentation that would require optical calibration...
August 10, 2015: Optics Express
Juliane Junesch, Gustav Emilsson, Kunli Xiong, Shailabh Kumar, Takumi Sannomiya, Hudson Pace, Janos Vörös, Sang-Hyun Oh, Marta Bally, Andreas B Dahlin
The biochemical processes of cell membranes are sensitive to the geometry of the lipid bilayer. We show how plasmonic "nanowells" provide label-free real-time analysis of molecules on membranes with detection of preferential binding at negative curvature. It is demonstrated that norovirus accumulate in invaginations due to multivalent interactions with glycosphingolipids.
October 7, 2015: Nanoscale
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