Towards a remote portable bio-affinity surface plasmon resonance analyser for environmental steroidal-pollutants

The widespread presence of chemicals with the capacity to disrupt the endocrine system in both wildlife and humans in our natural environment has increasingly become of major concern in the last ten years. Endocrine disrupting compounds (EDCs) are a group of compounds that pose a potentially dangerous and real threat to the health of both humans and wildlife. These substances can mimic or interfere with the biological pathways of natural endogenous signalling chemicals controlling the endocrine system (e.g. sex hormones). Endocrine disrupters are ubiquitous in water. The detection, monitoring and treatment of wastewaters and surface waters for EDCs would significantly help minimise the environmental burden imposed by these natural and synthetic compounds. To optimise such processes, an economical, in-situ or field-based detection technique for EDCs is required. The research presented in this thesis describes the development of a portable surface plasmon resonance device for the detection of endocrine disrupters in wastewater and surface waters. The first two result chapters describe the construction, development and optimisation of the portable analyser and immunoassay protocol using anti-estrogenic antibodies. A novel approach for regenerating the SPR sensing surface was achieved by using Persil biological laundry liquid (1%). The developed immunoassay showed a working range between 0.2 - 7µg/L for Estrone-3-Gulcuronide (E13G) in buffer. The detection of 17beta- Estradiol (E2) in buffer, synthetic wastewater and real wastewater samples was also carried out; the working range was 0.1 - 10µg/L; 0.3-7µg/L and 0.1-10µg/L respectively. The second part of the thesis describes the synthesis and protocol development of a photo-chromic dye and its application to immuno-sensing systems en route to a reversible bio-affinity antibody for application to regenerating biosensing surfaces. This approach was to demonstrate the concept of remote regeneration of the active sensing surface for a portable optical sensor.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Towards a remote portable bio-affinity surface plasmon resonance analyser for environmental steroidal-pollutants

The widespread presence of chemicals with the capacity to disrupt the endocrine system in both wildlife and humans in our natural environment has increasingly become of major concern in the last ten years. Endocrine disrupting compounds (EDCs) are a group of compounds that pose a potentially dangerous and real threat to the health of both humans and wildlife. These substances can mimic or interfere with the biological pathways of natural endogenous signalling chemicals controlling the endocrine system (e.g. sex hormones). Endocrine disrupters are ubiquitous in water. The detection, monitoring and treatment of wastewaters and surface waters for EDCs would significantly help minimise the environmental burden imposed by these natural and synthetic compounds. To optimise such processes, an economical, in-situ or field-based detection technique for EDCs is required. The research presented in this thesis describes the development of a portable surface plasmon resonance device for the detection of endocrine disrupters in wastewater and surface waters. The first two result chapters describe the construction, development and optimisation of the portable analyser and immunoassay protocol using anti-estrogenic antibodies. A novel approach for regenerating the SPR sensing surface was achieved by using Persil biological laundry liquid (1%). The developed immunoassay showed a working range between 0.2 - 7µg/L for Estrone-3-Gulcuronide (E13G) in buffer. The detection of 17beta- Estradiol (E2) in buffer, synthetic wastewater and real wastewater samples was also carried out; the working range was 0.1 - 10µg/L; 0.3-7µg/L and 0.1-10µg/L respectively. The second part of the thesis describes the synthesis and protocol development of a photo-chromic dye and its application to immuno-sensing systems en route to a reversible bio-affinity antibody for application to regenerating biosensing surfaces. This approach was to demonstrate the concept of remote regeneration of the active sensing surface for a portable optical sensor

Towards microbioprocess control:an inexpensive 3D printed microbioreactor with integrated online real-time glucose monitoring

Abstract Bioprocessing is of crucial importance in pharmaceutical, biofuel, food and other industries. Miniaturization of bioprocesses into microbioreactors allows multiplexing of experiments as well as reduction of reagent consumption and labour-intensity. A crucial part of the research within microbioreactors is biochemical analysis of product, byproduct and substrate concentrations that currently heavily relies on large analytical equipment. Biosensors are a promising analytical tool, however, integration into a microbioreactor is associated with challenges in ensuring sterility, appropriate sensing range, control of matrix effects and stability. In this work we present a novel biosensor integrated analytical chip that features an internal, actuated buffer flow in contact with a biosensor downstream and a diffusion limiting membrane exposed to the sample upstream. The technology was developed and tested using an electrochemical glucose oxidase biosensor and was found to successfully surmount the aforementioned challenges including the extension of the linear range of sensitivity to more than 20 g L⁻¹ for online, real time monitoring of glucose. The biosensor integration chip with the glucose biosensor was then mounted onto a 3D printed microbioreactor with 1 mL of internal volume. The system successfully monitored the consumption of glucose of Saccharomyces cerevisiae in real time for more than 8 h. The developed technology and measurement methodologies are transferrable to other biosensors and microbioreactors as well as large scale applications

Characterization of an enzymatic packed-bed microreactor:experiments and modeling

Abstract A micro packed-bed reactor (µPBR) based on two-parallel-plates configuration with immobilized Candida antarctica lipase B in the form of porous particles (Novozym® 435) was theoretically and experimentally characterized. A residence time distribution (RTD) within µPBRs comprising various random distributions of particles placed in one layer was computationally predicted by a mesoscopic lattice Boltzmann (LB) method. Numerical simulations were compared with measurements of RTD, obtained by stimulus-response experiment with a pulse input using glucose as a tracer, monitored by an electrochemical glucose oxidase microbiosensor integrated with the reactor. The model was validated by a good agreement between the experimental data and predictions of LB model at different conditions. The developed µPBR was scaled-up in length and width comprising either a single or two layers of Novozym® 435 particles and compared regarding the selected enzyme-catalyzed transesterification. A linear increase in the productivity with the increase in all dimensions of the µPBR between two-plates demonstrated very efficient and simple approach for the capacity rise. Further characterization of µPBRs of various sizes using the piezoresistive pressure sensor revealed very low pressure drops as compared to their conventional counterparts and thereby great applicability for production systems based on numbering-up approach

Microfluidic flow injection immunoassay system for algal toxins determination:a case of study

Abstract A novel flow injection microfluidic immunoassay system for continuous monitoring of saxitoxin, a lethal biotoxin, in seawater samples is presented in this article. The system consists of a preimmobilized G protein immunoaffinity column connected in line with a lab-on-chip setup. The detection of saxitoxin in seawater was carried out in two steps: an offline incubation step (competition reaction) performed between the analyte of interest (saxitoxin or Ag, as standard or seawater sample) and a tracer (an enzyme-conjugated antigen or Ag*) toward a specific polyclonal antibody. Then, the mixture was injected through a “loop” of a few μL using a six-way injection valve into a bioreactor, in line with the valve. The bioreactor consisted of a small glass column, manually filled with resin upon which G protein has been immobilized. When the mixture flowed through the bioreactor, all the antibody-antigen complex, formed during the competition step, is retained by the G protein. The tracer molecules that do not interact with the capture antibody and protein G are eluted out of the column, collected, and mixed with an enzymatic substrate directly within the microfluidic chip, via the use of two peristaltic pumps. When Ag* was present, a color change (absorbance variation, ΔAbs) of the solution is detected at a fixed wavelength (655 nm) by an optical chip docking system and registered by a computer. The amount of saxitoxin, present in the sample (or standard), that generates the variation of the intensity of the color, will be directly proportional to the concentration of the analyte in the analyzed solution. Indeed, the absorbance response increased proportionally to the enzymatic product and to the concentration of saxitoxin in the range of 3.5 × 10⁻⁷–2 × 10⁻⁵ ng ml⁻¹ with a detection limit of 1 × 10⁻⁷ ng ml⁻¹ (RSD% 15, S N⁻¹ equal to 3). The immunoanalytical system has been characterized, optimized, and tested with seawater samples. This analytical approach, combined with the transportable and small-sized instrumentation, allows for easy in situ monitoring of marine water contaminations