Stephen P Morgan

Stephen P Morgan
University of Nottingham | Notts · Faculty of Engineering

PhD

About

201
Publications
44,678
Reads
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2,578
Citations
Citations since 2017
61 Research Items
1372 Citations
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250

Publications

Publications (201)
Article
Full-text available
A long period grating Mach–Zehnder interferometer (LPGMZI) that consists of two identical long period gratings (LPGs) in a single fibre was developed to measure immunoglobulin M (IgM). The measured spectrum has fringes due to the interference between the core mode and cladding mode. This immunosensor inherits the advantages of an LPG and has the po...
Article
Propofol is used widely for intravenous anaesthesia during surgery and sedation in critical care. There is no method currently to assay the concentration of propofol in plasma in real time. The ability to do so would significantly improve patient safety. A novel approach to propofol assay consisting of Beta-Cyclodextrin (β−CD) assisted propofol-imp...
Article
Colorimetric measurement is a versatile, low-cost method for bio-/chemical sensing and that has importance in biomedical applications. General carbon dioxide (CO2) sensors based on colorimetric change of a pH indicator report only one parameter at a time and are cross-sensitive to relative humidity (RH). This work describes a novel optical fiber se...
Article
Full-text available
Compression therapy is widely used as the gold standard for management of chronic venous insufficiency and venous leg ulcers, and the amount of pressure applied during the compression therapy is crucial in supporting healing. A fibre optic pressure sensor using Fibre Bragg Gratings (FBGs) is developed in this paper to measure sub-bandage pressure w...
Article
Full-text available
Background: International newborn resuscitation guidelines recommend electrocardiogram (ECG) heart rate (HR) monitoring at birth. We evaluated the application time of pre-set ECG electrodes fixed to a polyethene patch allowing adhesive-free attachment to the wet skin of the newborn chest. Objectives: Using a three-electrode pre-set ECG patch con...
Article
This work reports an optical fibre probe functionalised with ‘cotton-shaped’ gold-silica nanostructures for relative humidity (RH) monitoring. The sensor response utilises the localised surface plasmon resonance (LSPR) of self-assembled nanostructures: gold nanospheres (40 nm) surrounded by one layer of poly (allylamine hydrochloride) and hydrophil...
Article
Full-text available
Incorrect endotracheal tube (ETT) cuff inflation pressure causes significant problems for intubated patients. The technical development and first in vivo use of a smart ETT for measurements at the cuff-trachea interface during mechanical ventilation are described. The intra-tracheal multiplexed sensing (iTraXS) ETT contains integrated optical fibre...
Article
Immunoglobulin A (IgA), IgG, and IgM immunosensors based on long period gratings (LPG) are developed in this work. An LPG has the advantages of being lightweight and small size, which provide possibility to design miniaturized immunosensors for point of care antibody tests. Poly (allylamine hydrochloride) (PAH) and silica nanoparticles (SiNPs) are...
Article
Full-text available
Pulse arrival time (PAT) is the delay time between the peak of the R-wave Electrocardiogram (ECG) signal and the peak of Photoplethysmogram (PPG) signals. This method is widely exploited for continuous cuffless blood pressure measurement. In the literature, the PAT was determined based on the mean at a certain number or certain period of heartbeats...
Article
Full-text available
Capillary refill time (CRT) refers to the time taken for body tissue to regain its colour after an applied blanching pressure is released. Usually, pressure is manually applied and not measured. Upon release of pressure, simple mental counting is typically used to estimate how long it takes for the skin to regain its colour. However, this method is...
Article
Full-text available
An optical fibre ammonia gas sensor utilising a functionalised four-leaf-clover-shaped suspended-core fibre (SCF) is demonstrated. The fibre is functionalised by depositing a thin layer of an ammonia sensitive dye (tetraphenylporphyrin tetrasulfonic acid hydrate) on the wall of the inner cavities of the SCF through capillary action. An in-line fibr...
Article
Full-text available
Temperature and humidity are essential parameters in monitoring the health of patients in critical care. An optical fibre sensor has been developed for simultaneous measurement of relative humidity (RH) and temperature at a single optical fibre tip based on the reflected intensity. Combining these measurements enables absolute humidity values to be...
Article
Conventional blood pressure (BP) measurement methods have a number of drawbacks such as being invasive, cuff-based or requiring manual operation. Many studies are focussed on emerging methods of noninvasive, cuff-less and continuous BP measurement, and using only photoplethysmography to estimate BP has become popular. Although it is well known that...
Article
Full-text available
A tip-based fibreoptic localised surface plasmon resonance (LSPR) sensor is reported for the sensing of volatile organic compounds (VOCs). The sensor is developed by coating the tip of a multi-mode optical fibre with gold nanoparticles (size: 40 nm) via a chemisorption process and further functionalisation with the HKUST-1 metal–organic framework (...
Article
Full-text available
Conventional blood pressure (BP) measurement methods have different drawbacks such as being invasive, cuff-based or requiring manual operations. There is significant interest in the development of non-invasive, cuff-less and continual BP measurement based on physiological measurement. However, in these methods, extracting features from signals is c...
Article
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Butyrylfentanyl is a new designer drug reported with growing use and related deaths. Routine toxicological analyses of this novel synthetic opioid drug have not been established yet. This work reports a fibre optic sensor that measures carboxyl-fentanyl which is the major metabolite of butyrylfentanyl presented in blood, providing a promising tool...
Article
Respiratory rate monitoring provides crucial information on the overall health condition of patients and a reliable, low cost respiratory rate monitor for normal hospital inpatient or home use would be of significant benefit. The proposed system measures light reflection from a Fibre Bragg Grating located near, and the total reflection spectrum fro...
Article
Full-text available
Textile-based systems are an attractive prospect for wearable technology as they can provide monitoring of key physiological parameters in a comfortable and unobtrusive form. A novel system based on multichannel optical fibre sensor probes integrated into a textile sleeve is described. The system measures the photoplethysmogram (PPG) at two wavelen...
Article
Full-text available
Development of a biocompatible pH sensor is of importance in biomedical applications, particularly for in vivo measurement, providing necessary information for clinical diagnosis and treatment such as chronic wounds and foetal acidosis. Traditional pH-indicator based optical sensors have problems of dye-leaching and photobleaching that restrict the...
Article
Full-text available
An optical fibre sensor for monitoring relative humidity (RH) changes during exercise is demonstrated. The humidity sensor comprises a tip coating of poly (allylamine hydrochloride) (PAH)/silica nanoparticles (SiO2 NPs) deposited using the layer-by-layer technique. An uncoated fibre is employed to compensate for bending losses that are likely to oc...
Article
Full-text available
The widely applied capillary refill time (CRT) measurement is currently performed by manually applying pressure and using a stopwatch to record the time taken for the skin to recover its normal colour after a blanching pressure is applied. This method is highly subjective and observer-dependent. This paper presents a new, integrated optical sensor...
Article
Full-text available
A novel method for the continual, cuff-less estimation of the systolic blood pressure (SBP) and diastolic blood pressure (DBP) values based on signal complexity analysis of the photoplethysmogram (PPG) and the electrocardiogram (ECG) is reported. The proposed framework estimates the blood pressure (BP) values obtained from signals generated from 14...
Article
Full-text available
Real time monitoring of bacterial attachment to medical devices provides opportunities to detect early biofilm formation and instigate appropriate interventions before infection develops. This study utilises long period grating (LPG) optical fibre sensors, incorporated into the lumen of endotracheal tubes (ETTs), to monitor in real time, Pseudomona...
Conference Paper
This paper presents the development of an optical-based fibre sensor system for pulse transit time (PTT) measurement. PTT is a promising method for cuffless continuous blood pressure (BP). In this study, the time delay between the R-wave peak of the Electrocardiogram (ECG) and the peak of the Photoplethysmogram (PPG) was measured and denoted as PTT...
Conference Paper
Full-text available
An endotracheal tube with integrated optical fibre sensors (fibre Bragg grating and photoplethysmography) is described. The system aims to ensure the appropriate cuff inflation pressure to achieve a gas seal but reduce pressure injury.
Conference Paper
Development of an optical fibre sensor based on a long period grating functionalised with surface imprinted polymers for detection of Dabrafenib, a B-Raf inhibitor drug, in the concentration range 0-800 μg/ml is reported.
Article
Full-text available
Ammonia (NH3) and carbon dioxide (CO2) are important breath biomarkers for diagnosis of renal and respiratory diseases. Simultaneous sensing of the two gases is useful for assessment of Helicobacter Pylori infection. This study introduces a multi-parameter optical fibre sensor by coating two different dyes, thymol blue and tetraphenylporphyrin tetr...
Article
Full-text available
The spatial resolution and light detected in fluorescence imaging for small animals are limited by light scattering, absorption and autofluorescence. To address this, novel near-infrared fluorescent contrast agents and imaging configurations have been investigated. In this paper, the influence of the light wavelength and imaging configurations (ful...
Conference Paper
Full-text available
An optical fibre temperature sensor modified with coating a thermochromic liquid crystal (TLC) film on the tip of fibre is reported. The interrogation is conducted in the wavelength domain using a CCD spectrometer and halogen light source. The TLC sensor shows a reversible wavelength shift of the reflective light peak in the detected temperature ra...
Conference Paper
Full-text available
Monitoring of key physiological and pharmacological parameters is an important part of a closed loop control system in critical care. Optical fiber sensors provide a versatile platform technology that can be easily incorporated into existing in-dwelling catheters or face masks. With appropriate functional coatings they can be used to monitor a rang...
Article
Full-text available
An array of optical fibre long period gratings (LPGs) has been demonstrated for biomedical application to monitor temperature and relative humidity (RH) changes in the air delivered by a mechanical ventilator operating in different modes. The LPG array consists of two gratings, where one was kept bare to monitor the temperature change and the secon...
Article
Full-text available
Diabetic foot ulcers are a major complication of diabetes and present a considerable burden for both patients and health care providers. As healing often takes many months, a method of determining which ulcers would be most likely to heal would be of great value in identifying patients who require further intervention at an early stage. Hyperspectr...
Article
A reflection-mode carbon dioxide (CO2) fiber optic sensor (FOS) is developed based on the colorimetric change of pH indicator dye thymol blue. The CO2 sensing film comprises thymol blue and tetramethylammonium hydroxide in the form of an ion pair doped in an organically modified silica film. A dip coating process was conducted to coat the sensing f...
Conference Paper
Full-text available
Blood pressure measurement is a significant part of preventive healthcare and has been widely used in clinical risk and disease management. However, conventional measurement does not provide continuous monitoring and sometimes is inconvenient with a cuff. In addition to the traditional cuff-based blood pressure measurement methods, some researchers...
Article
Full-text available
A novel optical sensor probe combining monitoring of blood oxygen saturation (SpO2) with contact pressure is presented. This is beneficial as contact pressure is known to affect SpO2 measurement. The sensor consists of three plastic optical fibres (POF) used to deliver and collect light for pulse oximetry, and a fibre Bragg grating (FBG) sensor to...
Article
Full-text available
Optical fibre sensors (OFS), as a result of their unique properties such as small size, no interference with electromagnetic radiation, high sensitivity and the ability to design multiplexed or distributed sensing systems, have found applications ranging from structural health monitoring to biomedical and point of care instrumentation. While the fo...
Article
An optical fibre long period grating (LPG) based volatile organic compound (VOC) sensor coated with ZIF-8, a material from the zeolite imidazolate framework (ZIF) family, functional coating is presented. ZIF-8 film was deposited onto the surface of the LPG using an in-situ crystallization technique by mixing freshly prepared 12.5 mM zinc nitrate he...
Article
Full-text available
An optical fibre long period grating (LPG) biosensor is appealing in the detection of biomolecules because of the high sensitivity, label-free and real-time measurement. The miniaturized size, ability of remote sensing and immunity to electromagnetic interference of the LPG biosensor provide various possibility of single-point sensing in situations...
Article
Objectives Postintubation laryngotracheal injury is common. Assessment of histopathological changes currently requires animal models. We set about developing a viable, resource effective animal model to study these effects and to develop a detailed tissue injury score. Methods Six pigs were anesthetized using a standard regimen. We intubated the t...
Article
Full-text available
In vivo imaging of self-illuminating bio-and chemiluminescent reporters is used to observe the physiology of small animals. However, strong light scattering by biological tissues results in poor spatial resolution of the optical imaging, which also degrades the quantitative accuracy. To overcome this challenging problem, focused ultrasound is used...
Article
Full-text available
Bioluminescence imaging has shown great potential for studying and monitoring disease progression in small animal pre-clinical imaging. However, absolute bioluminescence source recovery through tomographic multi-wavelength measurements is often hindered through the lack of quantitative accuracy and suffers from both poor localisation and quantitati...
Conference Paper
Real time monitoring of plasma propofol concentration is an important goal for safe anaesthesia. LPGs functionalized with host-guest imprinted TiO2 films were used to test propofol detection in aqueous solutions. The lowest detected concentration was 0.6 μM.
Conference Paper
Molecularly imprinted nanoparticles (MIPs) synthesized via a solid-phase synthesis process are successfully deposited on the surface of a long period grating (LPG) optical fibre sensor for detection of fentanyl in a liquid solution. Real-time detection of fentanyl can be observed from the LPG sensor. The wavelength change of LPG sensor linearly fit...
Article
An optical fibre long period grating (LPG) based carbon dioxide (CO2) sensor coated with HKUST-1, a material from the metal organic framework family, functional coating is presented. In-situ crystallization and layer by layer (LbL) techniques of HKUST-1 thin film synthesis are compared in terms of the feasibility of the deposition procedure (time a...
Article
Full-text available
An optical fiber sensor for ethanol detection in exhaled breath has been developed. It has been fabricated by functionalizing a Long Period Grating with a metal-organic framework, ZIF-8. The sensor’s response was tested by exposure to exhaled breath of a person before and after the ingestion of alcoholic drinks, showing a higher wavelength differen...
Article
A new approach for fluorescence imaging in optically turbid media centered on the use of nanoscale ultrasound-switchable FRET-based liposome contrast agents is reported. Liposomes containing lipophilic carbocyanine dyes as FRET pairs with emission wavelengths located in the near-infrared window are prepared. The efficacy of FRET and self-quenching...
Article
The sensitivity of a low-cost polymeric optical fibre humidity sensor based on transmittance changes due to evanescent wave absorption is reported using test measurements in an environmental chamber and of the skin. The layer-by-layer method was used to coat 30 mm of the central unclad section of a multimode polymeric optical fibre with 7 layers of...
Conference Paper
Bioluminescence imaging (BLI) is a commonly used imaging modality in biology to study cancer in vivo in small animals. Images are generated using a camera to map the optical fluence emerging from the studied animal, then a numerical reconstruction algorithm is used to locate the sources and estimate their sizes. However, due to the strong light sca...
Article
Full field laser Doppler imaging (LDI) and single exposure laser speckle contrast imaging (LSCI) are directly compared using a novel instrument which can concurrently image blood flow using both LDI and LSCI signal processing. Incorporating a commercial CMOS camera chip and a field programmable gate array (FPGA) the flow images of LDI and the contr...
Article
Full-text available
A new imaging contrast agent is reported that provides an increased fluorescent signal upon application of ultrasound (US). Liposomes containing lipids labelled with pyrene were optically excited and the excimer fluorescence emission intensity was detected in the absence and presence of an ultrasound field using an acousto-fluorescence setup. The a...
Data
Calculation of acoustic radiation force. (DOCX)
Data
Size distribution of PyPC labelled liposomes. (DOCX)
Conference Paper
An optical fibre sensor for simultaneous temperature and humidity measurements consisting of one fibre Bragg grating (FBG) to measure temperature and a mesoporous film of bilayers of Poly(allylamine hydrochloride)(PAH) and silica (SiO2) nanoparticles deposited onto the tip of the same fibre to measure humidity is reported. The hygroscopic film was...
Conference Paper
Optical fibre sensors have the potential to be incorporated into wound dressings to monitor moisture and predict healing without the need to remove the dressing. A low cost polymeric optical fibre humidity sensor based on evanescent wave absorption is demonstrated for skin humidity measurement. The sensor is fabricated by coating the fibre with a h...
Conference Paper
Full-text available
A method for measuring the contact pressure between an endotracheal tube cuff and the trachea was designed and developed by using a fibre Bragg grating (FBG) based optical fibre sensor. The FBG sensor is encased in an epoxy based UV-cured cuboid patch and transduces the transversely loaded pressure into an axial strain that induces wavelength shift...
Article
Objective: To develop a compact probe that can be used to monitor humidity in ventilator care equipment. A mesoporous film of alternate layers of Poly(allylamine hydrochloride) (PAH) and silica (SiO2) nanoparticles (bilayers), deposited onto an optical fibre was used. The sensing film behaves as a Fabry-Perot cavity of low-finesse where the absorp...
Article
Full-text available
A system has been developed in which multi-exposure laser speckle contrast imaging (LSCI) is implemented using a high frame rate CMOS imaging sensor chip. Processing is performed using a field programmable gate array (FPGA). The system allows different exposure times to be simulated by accumulating a number of short exposures. This has the advantag...
Conference Paper
Full-text available
An optical fibre Bragg grating (FBG) was used to measure local strain (due to contact pressure) at the interface of a cuffed endotracheal tube (ETT) tested in a tracheal model. The tracheal model consisted of a corrugated tube. Two FBG sensors written in a single optical fibre were attached to the outside wall of the cuff of the ETT. Intracuff endo...
Article
Full-text available
An optical fibre long period grating (LPG), modified with a coating of silica core gold shell (SiO2:Au) nanoparticles (NPs) deposited using the layer-by-layer method, was employed for the development of a biosensor. The SiO2:Au NPs were electrostatically assembled onto the LPG with the aid of a poly(allylamine hydrochloride) (PAH) polycation layer....