From sample to sensor: Usage and fabrication of point of care biosensor systems

Fast and reliable detection of infectious diseases is an important aspect of healthcare infrastructure. Point-of-Care (PoC) diagnostics - diagnostic tools that can be used quickly and easily at the patient-side - offer the possibility of a rapid diagnostic procedure without large infrastructure requirements. A common example for a PoC device is the Covid-19 rapid test, which was commonly used by many people during the pandemic. PoC devices can be extremely beneficial, not only during a pandemic but also for low-income countries with strained healthcare systems. This doctoral thesis examines the use and fabrication of PoC diagnostic devices. First, the current usage scenarios in low-income countries are critically analysed to identify factors that limit their widespread adaption. These newly acquired insights were consequently used to improve and develop several aspects of PoC systems. Firstly, a proof-of-application for the heat-transfer method, a novel method for pathogen detection, was established as a suitable sensor system for PoC use. Additionally, the usability of 3D-printing as a manufacturing method for low-cost microfluidic circuits was explored and consequently improved upon with the development of a completely novel technique coined ‘topographical vacuum sealing’. Microfluidic channels in PoC devices are used to bring the patient sample to the sensor surface. With this, this thesis aims to contribute to several aspects of PoC biosensing – from Sample to Sensor.