Christofer Toumazou

Christofer Toumazou
Imperial College London | Imperial · Department of Electrical and Electronic Engineering

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461
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Introduction
Skills and Expertise

Publications

Publications (461)
Article
Full-text available
This paper presents a fully automated point-of-care device for protein quantification using short-DNA aptamers, where no manual sample preparation is needed. The device is based on our novel aptamer-based methodology combined with real-time polymerase chain reaction (qPCR), which we employ for very sensitive protein quantification. DNA amplificatio...
Article
Full-text available
The negative effect of sedentary behaviour on type 2 diabetes markers is established, but the interaction with measures of physical activity is still largely unknown. Previous studies have analysed associations with single-activity models, which ignore the interaction with other behaviours. By including results from various analytical approaches, t...
Article
IntroductionImmunoassays targeting different SARS-CoV-2-specific antibodies are employed for seroprevalence studies. The degree of variability between immunoassays targeting anti-nucleocapsid (anti-NP; the majority) vs the potentially neutralising anti-spike antibodies (including anti-receptor-binding domain; anti-RBD), particularly in mild or asym...
Preprint
Full-text available
Isothermal amplification is an emerging approach for non-invasive, rapid and cost-effective real-time monitoring of cancer specific mutations through circulating tumour DNA (ctDNA). This study demonstrates a compact allele specific (AS) loop mediated isothermal amplification (LAMP) strategy, termed ‘AS-Mini-LAMP’, modelled using wild type (WT) and...
Article
Full-text available
Background As SARS-CoV-2 testing expands, particularly to widespread asymptomatic testing, high sensitivity point-of-care PCR platforms may optimise potential benefits from pooling multiple patients’ samples. Method We tested patients and asymptomatic citizens for SARS-CoV-2, exploring the efficiency and utility of CovidNudge (i) for detection in...
Article
Protein quantification is traditionally performed through enzyme-linked immunosorbent assay (ELISA), which involves long preparation times. To overcome this, new approaches use aptamers as an alternative to antibodies. In this paper, we present a new approach to quantify proteins with short DNA aptamers through polymerase chain reaction (PCR) resul...
Article
Full-text available
Background: Access to rapid diagnosis is key to the control and management of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Laboratory RT-PCR testing is the current standard of care but usually requires a centralised laboratory and significant infrastructure. We describe our diagnostic accuracy assessment of a novel, rapid point-of...
Preprint
Full-text available
Background Access to rapid diagnosis is key to the control and management of SARS-CoV-2. Reverse Transcriptase- Polymerase Chain Reaction (RT-PCR) testing usually requires a centralised laboratory and significant infrastructure. We describe the development and diagnostic accuracy assessment of a novel, rapid point-of-care RT-PCR test, the DnaNudge...
Article
Here, we present a new type of potassium sensor which possesses a combination of potassium sensing and anti-biofouling properties. Two major advancements were required to be developed with respect to the current technology; Firstly, design of surface linkers for this type of coating that would allow deposition of the potassiumselective coating on I...
Article
Full-text available
Background: A locally developed Case-Based Reasoning (CBR) algorithm, designed to augment antimicrobial prescribing in secondary care was evaluated. Methods: Prescribing recommendations made by a CBR algorithm were compared to decisions made by physicians in clinical practice. Comparisons were examined in two patient populations. Firstly, in pat...
Article
Full-text available
Breast cancer (BC) is a common cancer in women worldwide. Despite advances in treatment, up to 30% of women eventually relapse and die of metastatic breast cancer. Liquid biopsy analysis of circulating cell-free DNA fragments in the patients’ blood can monitor clonality and evolving mutations as a surrogate for tumour biopsy. Next generation sequen...
Article
Intensive attention on personalised skin-health solutions is on account of incomparable love of skin and an urgent need for effective treatment. In the meanwhile, people have great expectations on how to utilise genetic knowledge of our body to provide a precise solution for different individuals, such as daily use of skin-health products, since th...
Article
Full-text available
Closed-loop or intelligent neuromodulation allows adjustable, personalized neuromodulation which usually incorporates the recording of a biomarker, followed by implementation of an algorithm which decides the timing (when?) and strength (how much?) of stimulation. Closed-loop neuromodulation has been shown to have greater benefits compared to open-...
Article
Full-text available
Objective. Vagal nerve stimulation (VNS) has shown potential benefits for obesity treatment; however, current devices lack physiological feedback, which limit their efficacy. Changes in extracellular pH (pHe) have shown to be correlated with neural activity, but have traditionally been measured with glass microelectrodes, which limit their in vivo...
Article
Antibiotic resistance is an emerging global danger. Reaching responsible prescribing decisions requires the integration of broad and complex information. Artificial intelligence tools could support decision-making at multiple levels, but building them needs a transparent co-development approach to ensure their adoption upon implementation.
Article
Background Infection diagnosis can be challenging, relying on clinical judgement and non-specific markers of infection. We evaluated a supervised machine learning (SML) algorithm for diagnosing bacterial infection using routinely available blood parameters on presentation to hospital. Methods An SML algorithm was developed to classify cases into i...
Article
Full-text available
Background We developed a personalised antimicrobial information module co-designed with patients. This study aimed to evaluate the potential impact of this patient-centred intervention on short-term knowledge and understanding of antimicrobial therapy in secondary care. Methods Thirty previous patients who had received antibiotics in hospital wit...
Article
Full-text available
Objective: Vagus Nerve Stimulation (VNS) has shown great promise as a potential therapy for a number of conditions, such as epilepsy, depression and for Neurometabolic Therapies, especially for treating obesity. The objective of this study was to characterize the left ventral subdiaphragmatic gastric trunk of vagus nerve (SubDiaGVN) and to analyze...
Article
Full-text available
Background: Antimicrobial Resistance is threatening our ability to treat common infectious diseases and overuse of antimicrobials to treat human infections in hospitals is accelerating this process. Clinical Decision Support Systems (CDSSs) have been proven to enhance quality of care by promoting change in prescription practices through antimicrob...
Article
The rise of personalized diets is due to the emergence of nutrigenetics and genetic tests services. However, the recommendation system is far from mature to provide personalized food suggestion to consumers for daily usage. The main barrier of connecting genetic information to personalized diets is the complexity of data and the scalability of the...
Conference Paper
A Deep Belief Network architecture is proposed for prediction of DNA methylation characteristics across genetic regions. The proposed system uses an image analogous visualisation of DNA methylation features through an efficient mapping model. Implementation of this method has resulted in an accurate classification of DNA methylation for multiple Cp...
Article
Full-text available
Objective: Vagal nerve stimulation (VNS) has shown potential benefits for obesity treatment; however current devices lack physiological feedback, which limit their efficacy. Changes in extracellular pH (pH<sub>e</sub>) have shown to be correlated with neural activity, but have traditionally been measured with glass microelectrodes, which limit the...
Preprint
Closed loop neuromodulation, where the stimulation is controlled autonomously based on physiological events, has been more effective than open loop techniques. In the few existing closed loop implementations which have a feedback, indirect non-neurophysiological biomarkers have been typically used (e.g. heart rate, stomach distension). Although the...
Conference Paper
This paper describes the development of an array of individually addressable pH sensitive microneedles using injection moulding and their integration within a portable device for real-time wireless recording of pH distributions in biological samples. The fabricated microneedles are subjected to gold patterning followed by electrodeposition of iridi...
Poster
Full-text available
Objective: Safety is paramount in (semi-)automatic insulin delivery systems such as a closed-loop system, or a decision support system, for insulin dosing. Therefore, a safety layer is desired in order to minimise any risk of adverse events (i.e. hypo- and hyperglycaemia) due to any malfunctioning of the system (e.g. miscalculation of the dosing al...
Poster
Full-text available
Objective: Remote access to glucose related data (e.g. glucose measurements, meal insulin boluses, carbohydrates, exercise) is essential for safety of insulin decision support systems with capability to automatically adapt insulin therapy in type 1 diabetes (T1D). Decision support tools running on smartphones have the potential to send data through...
Article
Full-text available
The timely detection of viremia in HIV-infected patients receiving antiviral treatment is key to ensuring effective therapy and preventing the emergence of drug resistance. In high HIV burden settings, the cost and complexity of diagnostics limit their availability. We have developed a novel complementary metal-oxide semiconductor (CMOS) chip based...
Article
Over the past decade, ion-sensitive field-effect transistors (ISFETs) have played a major role in enabling the fabrication of fully integrated CMOS-based chemical sensing systems. This has allowed several new application areas, with the most promising being the fields of ion imaging and full genome sequencing. This paper reviews the new trends in f...
Article
Full-text available
Background: The Advanced Bolus Calculator for Diabetes (ABC4D) is an insulin bolus dose decision support system based on case-based reasoning (CBR). The system is implemented in a smartphone application to provide personalized and adaptive insulin bolus advice for people with type 1 diabetes. We aimed to assess proof of concept, safety, and feasib...
Article
Full-text available
Background: Insulin bolus calculators assist people with Type 1 diabetes (T1D) to calculate the amount of insulin required for meals to achieve optimal glucose levels but lack adaptability and personalization. We have proposed enhancing bolus calculators by the means of case-based reasoning (CBR), an established problem-solving methodology, by ind...
Poster
Objective: The ‘Advanced Bolus Calculator for Diabetes’ (ABC4D) relies on retrospective continuous glucose monitor (CGM) data and manual upload of this data for adaptation of bolus calculator parameters. The integration of CGM aims to reduce the workload and increase efficiency by fully automating the adaptation process. The second objective of thi...
Poster
Objective: To evaluate the glucose rate-of-change (ROC) at meal times during a six-week study (n=10) using the Advanced Bolus Calculator for Diabetes (ABC4D). ABC4D optimizes insulin bolus dosing based on previous postprandial glucose outcomes derived from continuous glucose monitoring (CGM) data. The aim of this work is to evaluate the potential u...
Poster
The Advanced Bolus Calculator for Diabetes (ABC4D) is a personalised insulin bolus advisory system that is able to adapt its parameters over time aiming to improve glycemic control. For safety reasons, performed adaptations are supervised by clinical experts who use their judgment to determine which scenarios are eligible to be used for adaptations...
Poster
Full-text available
Structured educational programmes for insulin dosing provide support for people with Type 1 diabetes on how to adapt insulin:carbohydrate ratios for meals with exercise or alcohol. The objective of this work is to analyse changes in the insulin:carbohydrate ratios and the resulting postprandial outcomes after a six-week pilot study using the adapti...
Poster
Full-text available
Objective: Currently available rapid acting insulin analogs (RAIs) are not fast enough to provide good post-prandial glycemic control in a fully automated artificial pancreas (AP) system (no user intervention required). Therefore, most of the existing AP systems incorporate a pre-meal insulin bolus to minimize postprandial glucose peaks. The advent...
Conference Paper
Electrical stimulation is the gold standard for modulating neural responses and has been successful in several invasive and non-invasive clinical therapies including Epilepsy and Depression. However, it poses a challenge of selectivity in non-invasive environments and for designers, safety and efficacy (including power). This project is developing...
Article
Full-text available
This paper presents the architecture and initial usability results of an advanced insulin bolus calculator for diabetes (ABC4D), which provides personalised insulin recommendations for people with diabetes by differentiating between various diabetes scenarios and automatically adjusting its parameters over time. The proposed platform comprises two...
Conference Paper
This paper presents an AC-coupled instrumentation amplifier for electroneurogram (ENG) activity recording. For this design, we evaluate gain and noise requirements based on interference sources (electrodes, power line, EMG). The circuit has been implemented in a commercially-available 0.35μm CMOS technology with total power consumption 460μW. The a...
Article
The advent of semiconductors in health care has enabled significant advancements in the development of point-of-care biomedical devices. Miniaturized portable systems are replacing bulky instruments. Telemedicine and remote care are being practiced in diagnostics. However, their communication with the biology is mainly in digital, whereas biology i...
Article
In this paper, the ion-sensitive field-effect transistor (ISFET) performance in unmodified complementary metal-oxide-semiconductor is thoroughly studied in terms of transconductance, threshold voltage, offset, and drift for the dimension and shape effects. It is shown that by increasing the ISFET sensing area, decoupling capacitors-as a function of...
Article
Full-text available
Background and objective: Insulin bolus calculators are simple decision support software tools incorporated in most commercially available insulin pumps and some capillary blood glucose meters. Although their clinical benefit has been demonstrated, their utilisation has not been widespread and their performance remains suboptimal, mainly because o...
Poster
Full-text available
Objective: A significant challenge of closed-loop insulin delivery systems for blood glucose control is to provide robustness against the uncertainty and variability inherent in diabetes management. In this work, a novel model predictive control algorithm that uses interval analysis to account for such uncertainty and variability is proposed. Metho...
Article
Full-text available
Background: The Bio-inspired Artificial Pancreas (BiAP) is a closed-loop insulin delivery system based on a mathematical model of beta-cell physiology and implemented in a microchip within a low-powered handheld device. We aimed to evaluate the safety and efficacy of the BiAP over 24 hours, followed by a substudy assessing the safety of the algori...
Poster
Full-text available
Objective: To evaluate safety of the Advanced Bolus Calculator for Type 1 Diabetes (ABC4D) application for mealtime insulin bolus calculation in a controlled clinical environment followed by assessment in the home. The ABC4D system consists of a smartphone-based platform running a novel decision support algorithm based on Case-Based Reasoning (CBR)...
Article
Full-text available
The minimal model of glucose-insulin dynamics is currently being used in several diabetes-related applications, such as investigating the glucose metabolism, and in the developments of model predictive controllers and fault detection techniques for automatic blood glucose control (i.e., artificial pancreas). Different approaches have been proposed...
Poster
Full-text available
Objective: Insulin bolus calculators are formula-based decision support tools using subject-specific parameters for insulin dose calculation. Although clinical benefit has been demonstrated, performance remains suboptimal due to technical and human factors. Accurate tuning of the parameters is important, and is currently done manually. We present,...
Conference Paper
Breast cancer is one of the most common cancer types in women, with 1 in 8 women having a lifetime risk of incidence. From the cases of primary breast cancer, more than 30% of diagnosed and treated cases will most likely lead to a metastasis, also known as cancer recurrence, within a period of 5-15 years from time of first diagnosis, dependent on t...
Article
Full-text available
This paper presents a low power current-mode method for monitoring differentially derived changes in pH from ion-sensitive field-effect transistor (ISFET) sensors, by adopting the Chemical Gilbert Cell. The fabricated system, with only a few transistors, achieves differential measurements and therefore drift minimisation of continuously recorded pH...
Article
Full-text available
Emerging materials in the field of implantable sensors should meet the needs for biocompatibility; transparency; flexibility and integrability. In this work; we present an integrated approach for implementing flexible bio-sensors based on thin Parylene C films that serve both as flexible support substrates and as active H+ sensing membranes within...
Article
Full-text available
The frequency response of an implantable antenna is key to the performance of a wireless implantable sensor. If the antenna detunes significantly, there are substantial power losses resulting in loss of accuracy. One reason for detuning is because of a change in the surrounding environment of an antenna. The pulsating anatomy of the human heart con...