Read by QxMD icon Read


Mayte Conejero-Muriel, Isaac Rodriguez-Ruiz, Cristobal Verdugo-Escamilla, Andreu Llobera, Jose Antonio Gavira
Microfluidics or lab-on-a-chip technology offer clear advantages over conventional systems such as a dramatic reduction of reagent consumption or a shorter analysis time, which are translated into costs effective systems. In this work, we present a photonic enzymatic lab on a chip reactor based on Cross-Linked Enzyme Crystals (CLECs), able to work in continuous flow, as a highly sensitive, robust, reusable and stable platform for continuous sensing with superior performance as compared to the state of the art...
October 26, 2016: Analytical Chemistry
Brandi L Baldock, James E Hutchison
DNA-functionalized gold nanoparticles have been increasingly applied as sensitive and selective analytical probes and biosensors. The DNA ligands bound to a nanoparticle dictate its reactivity, making it essential to know the type and number of DNA strands bound to the nanoparticle surface. Existing methods used to determine the number of DNA strands per gold nanoparticle (AuNP) require that the sequences be fluorophore labeled, which may affect the DNA surface coverage and reactivity of the nanoparticle, and/or require specialized equipment and other fluorophore-containing reagents...
October 26, 2016: Analytical Chemistry
Michael A Lee, Naveed Bakh, Gili Bisker, Emery N Brown, Michael S Strano
Cortisol is an important glucocorticoid hormone whose biochemistry influences numerous physiological and pathological processes. Moreover, it is a biomarker of interest for a number of conditions, including posttraumatic stress disorder, Cushing's syndrome, Addison's disease, and others. An implantable biosensor capable of real time monitoring of cortisol concentrations in adipose tissue may revolutionize the diagnosis and treatment of these disorders, as well as provide an invaluable research tool. Toward this end, a mathematical model, informed by the physiological literature, is developed to predict dynamic cortisol concentrations in adipose, muscle, and brain tissues, where a significant number of important processes with cortisol occur...
October 26, 2016: Advanced Healthcare Materials
Weiwei Ye, Yifan Xu, Lihao Zheng, Yu Zhang, Mo Yang, Peilong Sun
Histamine is an indicator of food quality and indispensable in the efficient functioning of various physiological systems. Rapid and sensitive determination of histamine is urgently needed in food analysis and clinical diagnostics. Traditional histamine detection methods require qualified personnel, need complex operation processes, and are time-consuming. In this study, a biofunctionalized nanoporous alumina membrane based electrochemical biosensor with magnetic nanoparticles (MNPs) concentration and signal amplification was developed for histamine determination...
October 22, 2016: Sensors
Muhammad Azhar Hayat Nawaz, Sajid Rauf, Gaelle Catanante, Mian Hasnain Nawaz, Gilvanda Nunes, Jean Louis Marty, Akhtar Hayat
Thin films of organic moiety functionalized carbon nanotubes (CNTs) from a very well-dispersed aqueous solution were designed on a screen printed transducer surface through a single step directed assembly methodology. Very high density of CNTs was obtained on the screen printed electrode surface, with the formation of a thin and uniform layer on transducer substrate. Functionalized CNTs were characterized by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Brunauer-Emmett- Teller (BET) surface area analyzer methodologies, while CNT coated screen printed transducer platform was analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS)...
October 6, 2016: Sensors
Rebecca J Stewart, Lachlan Whitehead, Brunda Nijagal, Brad E Sleebs, Guillaume Lessene, Malcolm J McConville, Kelly L Rogers, Christopher J Tonkin
Host cell invasion, exit and parasite dissemination is critical to the pathogenesis of apicomplexan parasites such as Toxoplasma gondii and Plasmodium spp. These processes are regulated by intracellular Ca(2+) signalling although the temporal dynamics of Ca(2+) fluxes and down-stream second messenger pathways are poorly understood. Here we use a genetically encoded biosensor, GFP-Calmodulin-M13-6 (GCaMP6), to capture Ca(2+) flux in live Toxoplasma and investigate the role of Ca(2+) signalling in egress and motility...
October 26, 2016: Cellular Microbiology
Jing Liu, Meirong Cui, Li Niu, Hong Zhou, Shusheng Zhang
Graphene composite connected with hemin and gold nanoparticles showing better performance for hydrogen peroxide decomposition compared that of three components alone or duplex hybrid complex. Our previous studies showed that, the morphology of the Au nanoparticles may greatly influence the catalytic activity of graphene-family peroxidase mimetic. Recently, interestingly we found that Au nanoflower could in-situ grow and form on the surface of Hemin/RGO. And the prickly morphology of this Au nanoflower brought higher catalytic ability with enhanced kinetic parameter than traditional Au nanoparticles which showed smooth surface on the surface of graphene...
October 25, 2016: Chemistry: a European Journal
Masataka Yamao, Kazuhiro Aoki, Naoto Yukinawa, Shin Ishii, Michiyuki Matsuda, Honda Naoki
We developed two new FRET imaging measures for intramolecular FRET biosensors, called linearly proportional (LP) and highly contrasting (HC) measures, which can be easily calculated by the fluorescence intensities of donor and acceptor as a ratio between their weighted sums. As an alternative to the conventional ratiometric measure, which non-linearly depends on the fraction of active molecule, we first developed the LP measure, which is linearly proportional to the fraction of active molecules. The LP measure inherently unmixes bleed-through signals and is robust against fluorescence noise...
2016: PloS One
Evan A Dubiel, Bruno Martin, Sylvain Vigier, Patrick Vermette
A quartz crystal microbalance (QCM) was constructed to assess if such a biosensor has value as a complementary real-time label-free analysis platform for the biopharmaceutical industry. This was achieved through modifying QCM crystals with a low-fouling carboxymethyl-dextran layer bearing Protein A, and then injecting solutions containing Etanercept (i.e., Enbrel(®)) into the QCM chambers. The kinetics of Enbrel(®) - Protein A interactions was modeled using the Langmuir binding model and Enbrel(®) concentrations between 0...
October 19, 2016: Colloids and Surfaces. B, Biointerfaces
Hui Xie, Yu-Tao Li, Yong-Min Lei, Yan-Lin Liu, Meng-Meng Xiao, Chuan Gao, Dai-Wen Pang, Wei-Hua Huang, Zhiyong Zhang, Guo-Jun Zhang
An ultrasensitive and highly efficient assay for real-time monitoring of nitric oxide (NO) at single cell level based on reduced graphene oxide (RGO) and iron-porphyrin functionalized graphene (FGPCs) field effect transistor (FET) biosensor is reported. A layer-to-layer assembly of RGO and FGPCs on a pre-fabricated FET sensor surface through p-p stacking interaction allowed superior electrical conductivity caused by RGO, and highly catalytic specificity induced by metalloporphyrin, ensuring the ultrasensitive and highly specific detection of NO...
October 25, 2016: Analytical Chemistry
Xiaosong Du, Yajuan Li, Gregory S Herman
Amorphous indium gallium zinc oxide (IGZO) field effect transistors (FETs) are a promising technology for a wide range of electronic applications. Herein, we fabricated and characterized FETs with a nanostructured IGZO network as a sensing transducer. The IGZO was patterned using colloidal lithography and electrohydrodynamic printing, where an 8 μm wide nanostructured close-packed hexagonal IGZO network was obtained. Electrical characterization of the nanostructured IGZO network FET demonstrated a drain-source current on-off ratio of 6...
October 25, 2016: Nanoscale
Tzu-Heng Wu, Chia-Chen Chang, Julien Vaillant, Aurélien Bruyant, Chii-Wann Lin
Smartphone camera based gold nanoparticle colorimetry (SCB-AuNP colorimetry) has shown good potential for point-of-care applications. However, due to the use of a camera as a photo-detector, there are major limitations to this technique such as a low bit resolution (∼8 bits mainstream) and a low data acquisition rate. These issues have limited the ultimate sensitivity of smartphone based colorimetry as well as the possibility to integrate efficiently a more sensitive approach such as detection based on a lock-in amplifier (LIA)...
October 25, 2016: Lab on a Chip
Sedef Ilk, Necdet Sağlam, Mustafa Özgen, Feza Korkusuz
Quorum sensing (QS) is a cell density dependent expression of species in bacteria mediated by compounds called autoinducers (AI). Several processes responsible for successful establishment of bacterial infection are mediated by QS. Inhibition of QS is therefore being considered as a new target for antimicrobial chemotherapy. Flavonoid compounds are strong antioxidant and antimicrobial agents but their applications are limited due to their poor dissolution and bioavailability. Our objective was to investigate the effect of kaempferol loaded chitosan nanoparticles on modulating QS mediated by AI in model bioassay test systems...
October 21, 2016: International Journal of Biological Macromolecules
Daniel P Brink, Celina Borgström, Felipe G Tueros, Marie F Gorwa-Grauslund
BACKGROUND: The sugar sensing and carbon catabolite repression in Baker's yeast Saccharomyces cerevisiae is governed by three major signaling pathways that connect carbon source recognition with transcriptional regulation. Here we present a screening method based on a non-invasive in vivo reporter system for real-time, single-cell screening of the sugar signaling state in S. cerevisiae in response to changing carbon conditions, with a main focus on the response to glucose and xylose. RESULTS: The artificial reporter system was constructed by coupling a green fluorescent protein gene (yEGFP3) downstream of endogenous yeast promoters from the Snf3p/Rgt2p, SNF1/Mig1p and cAMP/PKA signaling pathways: HXT1p/2p/4p; SUC2p, CAT8p; TPS1p/2p and TEF4p respectively...
October 24, 2016: Microbial Cell Factories
Keiichiro Yamanaka, Mun'delanji C Vestergaard, Eiichi Tamiya
In this review we present electrochemical biosensor developments, focusing on screen-printed electrodes (SPEs) and their applications. In particular, we discuss how SPEs enable simple integration, and the portability needed for on-field applications. First, we briefly discuss the general concept of biosensors and quickly move on to electrochemical biosensors. Drawing from research undertaken in this area, we cover the development of electrochemical DNA biosensors in great detail. Through specific examples, we describe the fabrication and surface modification of printed electrodes for sensitive and selective detection of targeted DNA sequences, as well as integration with reverse transcription-polymerase chain reaction (RT-PCR)...
October 21, 2016: Sensors
Shavini Wijesuriya, Krishna Burugapalli, Ruth Mackay, Godwin Chukwuebuka Ajaezi, Wamadeva Balachandran
Surface-enhanced Raman spectroscopy (SERS) substrates manufactured using complex nano-patterning techniques have become the norm. However, their cost of manufacture makes them unaffordable to incorporate into most biosensors. The technique shown in this paper is low-cost, reliable and highly sensitive. Chemical etching of solid Ag metal was used to produce simple, yet robust SERS substrates with broadband characteristics. Etching with ammonium hydroxide (NH₄OH) and nitric acid (HNO₃) helped obtain roughened Ag SERS substrates...
October 19, 2016: Sensors
Zheng Dai, I G Rosen, Chuming Wang, Nancy Barnett, Susan E Luczak
Alcohol researchers/clinicians have two ways to collect subject /patient field data, standard-drink self-report and the breath analyzer, neither of which is passive or accurate because active subject participation is required. Transdermal alcohol sensors have been developed to measure transdermal alcohol concentration (TAC), but they are used primarily as abstinence monitors because converting TAC into more meaningful blood/breath alcohol concentration (BAC/BrAC) is difficult. In this paper, BAC/BrAC is estimated from TAC by first calibrating forward distributed parameter-based convolution models for ethanol transport from the blood through the skin using patient-collected drinking data for a single drinking episode and a nonlinear pharmacokinetic metabolic absorption/elimination model to estimate BAC...
October 1, 2016: Mathematical Biosciences and Engineering: MBE
Selvaraj Naveenraj, Ramalinga Viswanathan Mangalaraja, Jerry J Wu, Abdullah M Asiri, Sambandam Anandan
Gold triangular nanoprisms and nanodecahedra (pentagonal bipyramids) were synthesized in the absence and presence of nanoseeds by a simple solvothermal synthesis through the reduction of Auric Chloride (HAuCl4) with poly(vinylpyrrolidone) (PVP) in N,N-dimethylformamide (DMF), respectively. These gold nanoparticles exhibit two plasmon resonance bands. The interaction of these gold nanoparticles with luminol was investigated using UV-vis and fluorescence spectroscopy since hefty number of environmental and biological sensors are based on the combination of luminol and gold nanoparticles...
October 24, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Christian Helbing, Robert Stößel, Dominik A Hering, Matthias Michael Lothar Arras, Jörg Bossert, Klaus D Jandt
Nanostructured surfaces have the potential to influence the assembly as well as the orientation of adsorbed proteins and may, thus, strongly influence the biomaterials performance. For the class of polymeric (bio)materials a reproducible and well characterized nanostructure is the ordered chain folded surface of a polyethylene single crystal (PE-SC). We tested the hypothesis that the trinodal-rod shaped protein human plasma fibrinogen (HPF) adsorbs on the (001) surface of PE-SCs along specific crystallographic directions...
October 24, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
X R Zhang, Y Zhang, F T Chen, Y Li, S S Zhang
A novel biosensor was developed based on the cation-exchange of CuS nanoparticles (NPs) and Cu(i)-based click chemistry of functionalized gold nanoparticles (AuNPs). As a proof-of-principle, novel applications of this method as a versatile biosensor for single-nucleotide polymorphisms (SNPs) and DNA methyltransferase (MTase) were presented.
October 24, 2016: Chemical Communications: Chem Comm
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"