Ruchi Gupta

Ruchi Gupta
University of Birmingham · School of Chemistry

Doctor of Philosophy

About

74
Publications
5,134
Reads
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455
Citations
Introduction
Ruchi Gupta is a Senior Lecturer and Birmingham Fellow in the University of Birmingham (UK). I combine chemistry, physics and engineering to develop polymeric optical biosensors. I use these sensors for on-site environmental analysis, point-of-care clinical diagnostics and wearable healthcare monitoring. See our website for more details: https://rguptagrouplab.com/
Additional affiliations
January 2017 - present
University of Birmingham
Position
  • Professor (Associate)
January 2017 - present
University of Birmingham
Position
  • Professor (Associate)
Description
  • Analytical Science
August 2014 - December 2016
University of Hull
Position
  • Lecturer
Education
September 2008 - August 2011
The University of Manchester
Field of study
  • Analytical Science
September 2005 - August 2007
McMaster University
Field of study
  • Engineering Physics
July 2001 - June 2005
Nanyang Technological University
Field of study
  • Electronics Engineering

Publications

Publications (74)
Conference Paper
A novel leaky waveguide grating (LWG) biosensor is reported where a continuous waveguide film of chitosan was photo patterned, resulting in a periodic modulation of the concentration of recognition elements (streptavidin in this case). This resulted in a periodic variation in the refractive index of the waveguide film, forming a phase grating at re...
Article
Current transmission grating sensors are unsuitable for use in typical samples that absorb and scatter light. To overcome this limitation, we report leaky waveguide gratings (LWGs), which operate in reflective...
Article
Full-text available
This is an unprecedented report of hydrogel gratings with an analyte responsive dye immobilised in alternating strips where the patterned dye is its own dispersive element to perform spectroscopy. At each wavelength, the diffraction efficiency of hydrogel gratings is a function of dye absorbance, which in turn is dependent on the concentration of a...
Article
The waveguide layer of diffraction-based leaky waveguides (LWs) must be made of materials that have low refractive index, are permeable to analytes, can be deposited by spin coating, and can be functionalised and crosslinked. These requirements are fulfilled by thin films of chitosan hydrogels. In this work, we studied the reproducibility of diffra...
Preprint
Food Allergy (FA) is now one of the most common chronic diseases of childhood often lasting throughout life and leading to significant worldwide healthcare burden. The precise mechanisms responsible for the development of this inflammatory condition are largely unknown; however, a multifactorial aetiology involving both environmental and genetic co...
Article
Full-text available
The resonance angles of leaky waveguides (LWs) can be observed directly as exponentially decaying interference fringes in waveguides with refractive index that is 0.001–0.01 higher than cover, and when illuminated with wedge-shaped light beam. This work for the first time shows that such LWs can be realised using hydrogels of acrylamide copolymeris...
Article
Full-text available
Background and aims The term “Food Allergy” refers to a complex global health problem with a wide spectrum of severity. However, a uniform definition of severe food allergy is currently missing. This systematic review is the preliminary step towards a state-of-the-art synopsis of the current evidence relating to the severity of IgE-mediated food al...
Article
Automation of fluid manipulation is needed to increase throughput and reproducibility of experiments while reducing the time spent by researchers on performing repetitive tasks. Current solutions are however bulky and expensive, and hence not suited to enable automation in academic laboratories. This work therefore reports a low cost, modular and p...
Article
Full-text available
Background and aims The term “Food Allergy” refers to a complex global health problem with a wide spectrum of severity. However, a uniform definition of severe food allergy is currently missing. This systematic review is the preliminary step towards a state-of-the-art synopsis of the current evidence relating to the severity of IgE-mediated food al...
Poster
Full-text available
1. R. Gupta, R., N. J. Goddard, Broadband absorption spectroscopy for rapid pH measurement in small volumes using an integrated porous waveguide, Analyst, 2017, 142, 169-176. 2. R. Gupta, N. J. Goddard, A proof-of-principle study for performing enzyme bioassays using substrates immobilized in a leaky optical waveguide. Sens. Actuat. B, 2017, 244, 5...
Article
Full-text available
We report a novel self-referenced diffraction-based leaky waveguide (LW) comprising a thin (~2 µm) film of a photofunctionalisable hydrogel created by covalent attachment of a biotinylated photocleavable linker to chitosan. Streptavidin attached to the chitosan via the photocleavable linker was selectively removed by shining 365 nm light through a...
Article
This review provides a historical perspective along with a tutorial on the concepts, instrumentation, and progress in the chemical and biological sensing applications of leaky waveguides (LWs) analytical use. The review compares the sensing performance (i.e. refractive index sensitivity, figure of merit, refractive index resolution, and absorption/...
Article
This report describes a Young interferometer (YI) sensor for real-time imaging of refractive index (RI) along the length of microchannels. The YI comprised a unique combination of Fresnel biprism and cylindrical lens to obtain two wedge shaped light beams, which ultimately overlapped to produce the interference fringes. The measured temporal and sp...
Article
Full-text available
The metal-clad leaky waveguide (MCLW) is an optical biosensor consisting of a metal layer and a low index waveguide layer on a glass substrate. This label-free sensor measures refractive index (RI) changes within the waveguide layer. This work shows the development and optimisation of acrylate based-hydrogel as the waveguide layer formed from PEG d...
Article
We report a very simple biosensor based on the direct observation of leaky waveguide (LW) modes as exponentially decaying interference fringes in the reflectivity curve. This phenomenon was only observed when the refractive index contrast between the waveguide and sample was low (0.002–0.005) and the LW was illuminated with a range of angles of inc...
Article
Leaky waveguide (LW) biosensors enable accurate measurements using small sample volumes and are cheap to produce, and hence, are advantageous in the area of point-ofuse devices. Yet, current instrumentation to test LW chips is both bulky and costly because of the use of expensive components, such as glass optics, and manufacturing techniques, such...
Data
Use of waveguides for imaging particles
Code
Source code for PC software for 3D printed instrument
Data
PCB for 3D printed instrument
Code
xTimeComposer software for 3D printed instrument
Data
STL files for 3D printed instrument
Article
This proof-of-principle study demonstrates the feasibility of a leaky waveguide (LW) aptasensor, where aptamers were immobilised in a mesoporous chitosan waveguiding film, for the detection of thrombin. This work has demonstrated that aptamers immobilised in hydrogels retain their affinity and selectivity towards their target and thus can be used a...
Article
Front Cover: In article number 1900228 by Ruchi Gupta and co‐workers, a water‐soluble chemical method for making a photo‐functionalizable hydrogel is reported for the fabrication of optical grating sensors with high (>3) aspect ratio. This grating sensor contains a dye that is sensitive to pH, resulting in changes in the diffraction pattern as the...
Article
Improving the limit of detection by preconcentration and reducing the response time of optical biosensors are key requirements to enable their use in point of care (PoC) applications. To address these requirements, we have shown that integration of isoelectric focusing (IEF) at a pH step with a leaky waveguide (LW) sensor containing a non-specific...
Article
Volume amplitude gratings made of mesoporous hydrogels are beneficial for sensing, but are difficult to fabricate because they involve creating high aspect ratio features in soft materials. A novel photofunctionalizable hydrogel is reported and its suitability for fabricating grating sensors is demonstrated comprising of features with an aspect rat...
Poster
Full-text available
Acute respiratory illnesses (ARIs) are either bacterial or viral, but both present with very similar symptoms in patients. Antibiotics are therefore being grossly overprescribed by doctors for viral infections, of which they have no use; approximately 60% of ARIs are viral, while the prescription rate of antibiotics for ARIs exceeds 70%. Procalcit...
Article
Full-text available
We report a method where the refractive index increments of an iron storage protein, ferritin, and apoferritin (ferritin minus iron) were measured over the wavelength range of 450 to 678 nm to determine the average iron content of the protein. The protein used in this study had ~3375 iron atoms per molecule. The measurement of optical dispersion ov...
Poster
Full-text available
Optical structures made of photo patternable hydrogels have emerged as promising multi-analyte biosensors [1] for point-of-care diagnostics and chronic wound monitoring such as diabetic foot ulcers (DFUs), which pose significant societal challenges and currently cost ~£3 billion p.a. in the UK alone [2, 3]. Additionally, the incidence of chronic wo...
Data
This work reports a novel sensor with internal referencing to eliminate the undesirable effects of variations in background refractive index and non-specific interactions. The sensor differs from previously reported internally-referenced devices in its basic principle of operation and physical structure.
Presentation
Full-text available
We investigated a label-free optical biosensor for analyte measurement in wound fluid based on a Resonant Mirror (RM) device and 3D printed instrumentation. This work builds on our previous report of a novel RM device (DOI: 10.1039/c3an00263b), which consisted of silica sol–gel spacer and polystyrene waveguide layers spin-coated on a standard micro...
Poster
Full-text available
We report a polyacrylamide-allylamine based hydrogel where the amine groups are caged with a photolabile group, 4,5-Dimethoxy-2-nitrobenzyl chloroformate (NVOC) to fabricate optical structures.
Presentation
Chronic wounds such as diabetic foot ulcers (DFUs) pose significant societal challenges and currently cost ~£3 billion in the UK alone. Wounds are typically covered with dressings to facilitate healing. Standard dressings, however, do not provide insights into the status of the wound underneath. Thus, dressings are often changed to examine and asse...
Poster
We report a photofunctionalisable polysaccharide, agarose, hydrogel.
Article
Full-text available
Food protein–induced enterocolitis (FPIES) is a non-IgE cell- mediated food allergy that can be severe and lead to shock. Despite the potential seriousness of reactions, awareness of FPIES is low; high-quality studies providing insight into the pathophysiology, diagnosis, and management are lacking; and clinical outcomes are poorly established. Thi...
Article
This work is a proof-of-principle study on the feasibility of performing enzyme bioassays using a dye-doped leaky waveguide (DDLW) where the substrate was immobilised in the entire volume of the waveguide and the fraction of light confined in the waveguide interacted with the absorbing product formed as a result of the enzyme's action on the substr...
Article
Broadband absorption spectroscopy integrated with microfluidics is widely used to measure the pH of samples available in small volumes. Single pass absorption spectroscopy, however, suffers from poor minimum detectable absorption coefficient because the optical path length is determined by the physical dimensions of microchannels. As a result, eith...
Article
Simultaneous refractive index monitoring and absorption spectroscopy in small volumes common to both measurements using single light source and detector are beneficial, but challenging to perform. This work presents an optical device consisting of a porous waveguide deposited on glass, which is called dye-doped leaky waveguide (DDLW), for this purp...
Article
Background: Multiple breath washout (MBW) in infants presents a number of technical challenges. Conventional MBW is based on simultaneous measurement of flow and gas concentrations. These two signals are aligned and combined to derive expired gas volumes from which lung volumes and measures of ventilation inhomogeneity are calculated. Accuracy of...
Article
Full-text available
Background The Innocor device contains a highly sensitive photoacoustic gas analyser that has been used to perform multiple breath washout (MBW) measurements using very low concentrations of the tracer gas SF6. Use in smaller subjects has been restricted by the requirement for a gas analyser response time of <100 ms, in order to ensure accurate est...
Presentation
Full-text available
This work reports a novel sensor, called a leaky waveguide grating (LWG), consisting of an array of strip leaky waveguides. The LWG produces a π-phase difference between the light reflected from the strips and the area between the strips at the resonance angle (i.e. the angle at which light couples in the strips). As a result, a strong diffraction...
Conference Paper
Full-text available
This work reports a novel sensor with internal referencing to eliminate the undesirable effects of variations in background refractive index and non-specific interactions. The sensor is based on a two layer metal-clad leaky waveguide that supports two optical modes that are largely confined to one or other of the two waveguide layers. The lower or...
Article
Full-text available
Typically, Electrowetting on dielectric (EWOD) digital microfluidic devices consist of an array of metal electrodes covered with a continuous hydrophobic dielectric layer. The monitoring of droplet position and detection in EWOD is usually achieved via microscopy, thereby resulting in increasing the size and complexity of the instrumentation associ...
Article
A novel resonant mirror (RM) device, which consisted of silica sol-gel spacer and polystyrene waveguide layers on a standard microscope slide glass substrate, was developed in this work. The device was successfully used to measure the absorption spectrum of methylene blue with a limit of detection (LOD) of at most 20.8 μM at 635 nm and a minimum de...
Article
Evanescent wave (EW) broadband absorption spectroscopy is commonly interfaced with a range of analytical systems, including microfluidic flow cells, for identification and quantitation of species. A miniaturised spectrometer integrated with a microfluidic flow cell is useful to permit on-site analysis of samples. This work reports a novel leaky wav...
Article
Evanescent wave (EW) broadband absorption spectroscopy is commonly interfaced with a range of analytical systems, including microfluidic flow cells, for identification and quantitation of species. A miniaturised spectrometer integrated with a microfluidic flow cell is useful to permit on-site analysis of samples. This work reports a novel leaky wav...
Article
Broadband absorption spectroscopy is advantageous because the full spectral profile of an analyte can permit identification of species. This work for the first time investigates the feasibility of a metal clad leaky waveguide (MCLW) device to obtain an absorption spectrum of an analyte of interest, methylene blue, using a white light source in a mi...
Article
Full-text available
This work reports a novel sensor with internal referencing to eliminate the undesirable effects of variations in background refractive index and non-specific interactions. The sensor is based on a two layer metal-clad leaky waveguide that supports two optical modes that are largely confined to one or other of the two waveguide layers. The lower or...
Article
The primary requirement for a mixing operation in droplet-based microfluidic devices is an accurate pairing of droplets of reaction fluids over an extended period of time. In this paper, a novel device for self-synchronous production of droplets has been demonstrated. The device uses a change in impedance across a pair of electrodes introduced due...
Article
Cellobiohydrolase (CBH) is an important enzyme for the conversion of lignocellulosic biomass to ethanol. This work separated the glycoforms of CBH possessing different numbers of neutral mannoses using capillary zone electrophoresis (CZE) in a 50 mM, pH 7.5 phosphate buffer. The method analysed CBH in an intact form using a polyacrylamide coated fu...
Article
Bagasse is one of the waste crop materials highlighted as commercially viable for cellulosic bio-ethanol production via enzymatic conversion to release fermentable sugars. Genetically modified sugarcane expressing cellobiohydrolases (CBH), endoglucanase (EG), and β-glucosidases (BG) provide a more cost-effective route to cellulose breakdown compare...
Article
The foremost requirement of quantification of cellulases expressed in genetically modified sugarcane is an efficient sample clean-up. This work investigates the feasibility of isotachophoresis for this purpose. An electrolyte system comprising a leading electrolyte of 10mM formic acid at pH 9.0 and a terminating electrolyte of 10mM β-alanine was de...

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Cited By

Projects

Projects (9)
Archived project
Electrophoresis and Microfluidics
Archived project
Optical biosensors
Archived project
Photopolymerisable acrylate hydrogels with tailored density of functional groups