Lab-on-a-chip device to quantify buffer capacity of blood

• Main Author: Gandhi, Sahir
• Other Authors: O'Hare, Danny, Boutelle, Martyn
• Format: Doctoral or Postdoctoral Thesis
• Language: unknown
• Published: Imperial College London 2016
• Subjects: Sickle; Carbonic acid
• Online Access: http://hdl.handle.net/10044/1/34399; https://doi.org/10.25560/34399

An accurate estimation of physiological buffer capacity and total titratable buffer concentration of blood can give a great deal of insight into the physiological stability of a patient and yet it remains an undervalued diagnostic marker. This thesis highlights the need for a lab-on-chip device to quantify buffer capacity of whole blood samples by estimating the total titratable buffer concentration. Buffer capacity is quantified by titrating the buffer to its end point using monoprotic acids. More sophisticated ways include electrolytic titration, i.e. producing a proton flux using electrodes in a controlled environment. This thesis looks at a novel approach to electrolytic (coulometric) titration by inhibiting the production of OH ions during electrolysis and titrating the sample due to the proton flux from the anode. By definition, is the amount of acid or base added to change the pH of 1 litre of buffer by 1 pH unit. The carbonic acid bicarbonate buffer system is the most important buffer that maintains the body’s pH within a stable range. To quantify this buffer’s total buffering concentration, it is important to know and indicate its titration end point which signifies the total exhaustion of all buffering constituents. Colorimetric indicators have been used to indicate this end point which can be quantified through cameras or spectrophotometric techniques. Using this novel coulometric titrator and the colorimetric end point detector, this thesis presents a portable lab-on-chip prototype to spectrophotometrically quantify total titratable buffer concentration. Clinically, this device could benefit patients with sickle cell disease, nephritic disease and those admitted in accident and emergency wards. This research work is aimed at presenting a proof-of-concept for a device that can titrate nano-litre samples and be able to detect the end point of a titration in a controlled way. Open Access