Research

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371 KiB

Open AccessArticle

Gait Event Detection on Level Ground and Incline Walking Using a Rate Gyroscope

by Paola Catalfamo, Salim Ghoussayni and David Ewins

Sensors 2010, 10(6), 5683-5702; https://doi.org/10.3390/s100605683 - 04 Jun 2010

Cited by 124 | Viewed by 14351

Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. Accurate determination of the Initial Contact of the foot with the floor (IC) and the final contact or Foot Off (FO) on different terrains is important. This paper [...] Read more.

Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. Accurate determination of the Initial Contact of the foot with the floor (IC) and the final contact or Foot Off (FO) on different terrains is important. This paper describes the evaluation of a gyroscope placed on the shank for determination of IC and FO in subjects walking outdoors on level ground, and up and down an incline. Performance was compared with a reference pressure measurement system. The mean difference between the gyroscope and the reference was less than –25 ms for IC and less than 75 ms for FO for all terrains. Detection success was over 98%. These results provide preliminary evidence supporting the use of the gyroscope for gait event detection on inclines as well as level walking. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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433 KiB

Open AccessArticle

Biosensing for the Environment and Defence: Aqueous Uranyl Detection Using Bacterial Surface Layer Proteins

by David J.R. Conroy, Paul A. Millner, Douglas I. Stewart and Katrin Pollmann

Sensors 2010, 10(5), 4739-4755; https://doi.org/10.3390/s100504739 - 10 May 2010

Cited by 18 | Viewed by 12371

Abstract

The fabrication of novel uranyl (UO₂²⁺) binding protein based sensors is reported. The new biosensor responds to picomolar levels of aqueous uranyl ions within minutes using Lysinibacillus sphaericus JG-A12 S-layer protein tethered to gold electrodes. In comparison to traditional self [...] Read more.

The fabrication of novel uranyl (UO₂²⁺) binding protein based sensors is reported. The new biosensor responds to picomolar levels of aqueous uranyl ions within minutes using Lysinibacillus sphaericus JG-A12 S-layer protein tethered to gold electrodes. In comparison to traditional self assembled monolayer based biosensors the porous bioconjugated layer gave greater stability, longer electrode life span and a denser protein layer. Biosensors responded specifically to UO₂²⁺ ions and showed minor interference from Ni²⁺, Cs⁺, Cd²⁺ and Co²⁺. Chemical modification of JG-A12 protein phosphate and carboxyl groups prevented UO₂²⁺ binding, showing that both moieties are involved in the recognition to UO₂²⁺. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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555 KiB

Open AccessArticle

A Multiwell Electrochemical Biosensor for Real-Time Monitoring of the Behavioural Changes of Cells in Vitro

by Daman J. Adlam and David E. Woolley

Sensors 2010, 10(4), 3732-3740; https://doi.org/10.3390/s100403732 - 13 Apr 2010

Cited by 9 | Viewed by 8764

Abstract

We report the development of a multiwell biosensor for detecting changes in the electrochemical open circuit potential (OCP) generated by viable human cells in vitro. The instrument features eight culture wells; each containing three gold sensors around a common silver/silver chloride reference [...] Read more.

We report the development of a multiwell biosensor for detecting changes in the electrochemical open circuit potential (OCP) generated by viable human cells in vitro. The instrument features eight culture wells; each containing three gold sensors around a common silver/silver chloride reference electrode, prepared using screen-printed conductive inks. The potential applications of the device were demonstrated by monitoring rheumatoid synovial fibroblasts (RSF) and HepG2 hepatocarcinoma cells in response to chemical and biological treatments. This technology could provide an alternative to conventional end-point assays used in the fields of chemotherapy, toxicology and drug discovery. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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4378 KiB

Open AccessArticle

Whispering Gallery Modes in Standard Optical Fibres for Fibre Profiling Measurements and Sensing of Unlabelled Chemical Species

by Anna Boleininger, Thomas Lake, Sophia Hami and Claire Vallance

Sensors 2010, 10(3), 1765-1781; https://doi.org/10.3390/s100301765 - 03 Mar 2010

Cited by 43 | Viewed by 13260

Abstract

Whispering gallery mode resonances in liquid droplets and microspheres have attracted considerable attention due to their potential uses in a range of sensing and technological applications. We describe a whispering gallery mode sensor in which standard optical fibre is used as the whispering [...] Read more.

Whispering gallery mode resonances in liquid droplets and microspheres have attracted considerable attention due to their potential uses in a range of sensing and technological applications. We describe a whispering gallery mode sensor in which standard optical fibre is used as the whispering gallery mode resonator. The sensor is characterised in terms of the response of the whispering gallery mode spectrum to changes in resonator size, refractive index of the surrounding medium, and temperature, and its measurement capabilities are demonstrated through application to high-precision fibre geometry profiling and the detection of unlabelled biochemical species. The prototype sensor is capable of detecting unlabelled biomolecular species in attomole quantities. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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Review

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2493 KiB

Open AccessReview

Microfluidic Systems for Biosensing

by Kuo-Kang Liu, Ren-Guei Wu, Yun-Ju Chuang, Hwa Seng Khoo, Shih-Hao Huang and Fan-Gang Tseng

Sensors 2010, 10(7), 6623-6661; https://doi.org/10.3390/s100706623 - 09 Jul 2010

Cited by 94 | Viewed by 20268

Abstract

In the past two decades, Micro Fluidic Systems (MFS) have emerged as a powerful tool for biosensing, particularly in enriching and purifying molecules and cells in biological samples. Compared with conventional sensing techniques, distinctive advantages of using MFS for biomedicine include ultra-high sensitivity, [...] Read more.

In the past two decades, Micro Fluidic Systems (MFS) have emerged as a powerful tool for biosensing, particularly in enriching and purifying molecules and cells in biological samples. Compared with conventional sensing techniques, distinctive advantages of using MFS for biomedicine include ultra-high sensitivity, higher throughput, in-situ monitoring and lower cost. This review aims to summarize the recent advancements in two major types of micro fluidic systems, continuous and discrete MFS, as well as their biomedical applications. The state-of-the-art of active and passive mechanisms of fluid manipulation for mixing, separation, purification and concentration will also be elaborated. Future trends of using MFS in detection at molecular or cellular level, especially in stem cell therapy, tissue engineering and regenerative medicine, are also prospected. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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1815 KiB

Open AccessReview

Metal Oxide Semi-Conductor Gas Sensors in Environmental Monitoring

by George F. Fine, Leon M. Cavanagh, Ayo Afonja and Russell Binions

Sensors 2010, 10(6), 5469-5502; https://doi.org/10.3390/s100605469 - 01 Jun 2010

Cited by 1154 | Viewed by 46657

Abstract

Metal oxide semiconductor gas sensors are utilised in a variety of different roles and industries. They are relatively inexpensive compared to other sensing technologies, robust, lightweight, long lasting and benefit from high material sensitivity and quick response times. They have been used extensively [...] Read more.

Metal oxide semiconductor gas sensors are utilised in a variety of different roles and industries. They are relatively inexpensive compared to other sensing technologies, robust, lightweight, long lasting and benefit from high material sensitivity and quick response times. They have been used extensively to measure and monitor trace amounts of environmentally important gases such as carbon monoxide and nitrogen dioxide. In this review the nature of the gas response and how it is fundamentally linked to surface structure is explored. Synthetic routes to metal oxide semiconductor gas sensors are also discussed and related to their affect on surface structure. An overview of important contributions and recent advances are discussed for the use of metal oxide semiconductor sensors for the detection of a variety of gases—CO, NOx, NH3 and the particularly challenging case of CO₂. Finally a description of recent advances in work completed at University College London is presented including the use of selective zeolites layers, new perovskite type materials and an innovative chemical vapour deposition approach to film deposition. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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887 KiB

Open AccessReview

Carbon Nanostructure-Based Field-Effect Transistors for Label-Free Chemical/Biological Sensors

by PingAn Hu, Jia Zhang, Le Li, Zhenlong Wang, William O’Neill and Pedro Estrela

Sensors 2010, 10(5), 5133-5159; https://doi.org/10.3390/s100505133 - 25 May 2010

Cited by 138 | Viewed by 17832

Abstract

Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has [...] Read more.

Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has advantages of high sensitivity, low decreased energy consumption and potentially highly miniaturized integration. Owing to their particular structure, excellent electrical properties and high chemical stability, carbon nanotube and graphene based electrical devices have been widely developed for high performance label-free chemical/biological sensors. Here, we review the latest developments of carbon nanostructure-based transistor sensors in ultrasensitive detection of chemical/biological entities, such as poisonous gases, nucleic acids, proteins and cells. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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1301 KiB

Open AccessReview

Sonochemically Fabricated Microelectrode Arrays for Use as Sensing Platforms

by Stuart D. Collyer, Frank Davis and Séamus P.J. Higson

Sensors 2010, 10(5), 5090-5132; https://doi.org/10.3390/s100505090 - 25 May 2010

Cited by 9 | Viewed by 11590

Abstract

The development, manufacture, modification and subsequent utilisation of sonochemically-formed microelectrode arrays is described for a range of applications. Initial fabrication of the sensing platform utilises ultrasonic ablation of electrochemically insulating polymers deposited upon conductive carbon substrates, forming an array of up to 70,000 [...] Read more.

The development, manufacture, modification and subsequent utilisation of sonochemically-formed microelectrode arrays is described for a range of applications. Initial fabrication of the sensing platform utilises ultrasonic ablation of electrochemically insulating polymers deposited upon conductive carbon substrates, forming an array of up to 70,000 microelectrode pores cm^–2. Electrochemical and optical analyses using these arrays, their enhanced signal response and stir-independence area are all discussed. The growth of conducting polymeric “mushroom” protrusion arrays with entrapped biological entities, thereby forming biosensors is detailed. The simplicity and inexpensiveness of this approach, lending itself ideally to mass fabrication coupled with unrivalled sensitivity and stir independence makes commercial viability of this process a reality. Application of microelectrode arrays as functional components within sensors include devices for detection of chlorine, glucose, ethanol and pesticides. Immunosensors based on microelectrode arrays are described within this monograph for antigens associated with prostate cancer and transient ischemic attacks (strokes). Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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3567 KiB

Open AccessReview

Oxidant Sensing by Protein Kinases A and G Enables Integration of Cell Redox State with Phosphoregulation

by Joseph R. Burgoyne and Philip Eaton

Sensors 2010, 10(4), 2731-2751; https://doi.org/10.3390/s100402731 - 26 Mar 2010

Cited by 18 | Viewed by 13925

Abstract

The control of vascular smooth muscle contractility enables regulation of blood pressure, which is paramount in physiological adaptation to environmental challenges. Maintenance of stable blood pressure is crucial for health as deregulation (caused by high or low blood pressure) leads to disease progression. [...] Read more.

The control of vascular smooth muscle contractility enables regulation of blood pressure, which is paramount in physiological adaptation to environmental challenges. Maintenance of stable blood pressure is crucial for health as deregulation (caused by high or low blood pressure) leads to disease progression. Vasotone is principally controlled by the cyclic nucleotide dependent protein kinases A and G, which regulate intracellular calcium and contractile protein calcium sensitivity. The classical pathways for activation of these two kinases are well established and involve the formation and activation by specific cyclic nucleotide second messengers. Recently we reported that both PKA and PKG can be regulated independently of their respective cyclic nucleotides via a mechanism whereby the kinases sense cellular oxidant production using redox active thiols. This novel redox regulation of these kinases is potentially of physiological importance, and may synergise with the classical regulatory mechanisms. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in the UK)

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