Development of a multiplex sensing platform for the accurate and rapid diagnosis of sepsis

Demertzis, Nikolaos 2020. Development of a multiplex sensing platform for the accurate and rapid diagnosis of sepsis. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Sepsis derives from an uncontrolled response of the host immune system to a pathogenic insult. The complex, rapidly evolving nature of the condition makes diagnosis difficult, and to date a single ‘gold-standard’ biomarker has not been reported. An increasing number of studies suggest that monitoring of a panel of biomarkers, ideally at point-of-care, is needed. The present study therefore focused on the development of a multiplex biosensing platform targeting lipopolysaccharide (LPS), c-reactive protein (CRP), and procalcitonin (PCT). The study designed a series of electrochemical sensors targeting the three selected biomarkers. Whilst all systems employed aptamers as the recognition element, a hybrid system combining aptamer and molecular imprinting technology was also developed for LPS. Following optimisation of sensor design, electrochemical impedance spectroscopy was used to evaluate performance (binding affinity (Kd), sensitivity, selectivity and dynamic range). Aptasensors were developed for all markers with varying degrees of success. Whilst the optimised aptasensors for LPS and CRP demonstrated good performance, the PCT aptasensor showed poor stability. Despite these issues however, a limit of detection (LOD) of ~ 25 pg/ml was achieved. LODs for LPS and CRP were 100 and 250 fg/ml respectively. The use of a hybrid imprinting approach further enhanced the performance of the LPS detection system, taking the LOD down to 1 fg/ml whilst also increasing binding capacity. Although aptamer-based sensing systems have been described for LPS and CRP, to the best of our knowledge, this is the first report of a such a system targeting PCT. The hybrid imprinting strategy exploited in the study has previously been demonstrated for prostate specific antigen, however this is the first report of such an approach being used for non-protein targets. The recognition of such molecules using conventional imprinting approaches has been largely unsuccessful; the method described herein should be translatable to other biologically relevant targets.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Pharmacy
Subjects:	Q Science > Q Science (General)
Date of First Compliant Deposit:	4 January 2021
Last Modified:	26 Oct 2021 01:37
URI:	https://orca.cardiff.ac.uk/id/eprint/137251

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