Advancements in medical diagnostics have allowed us to understand the underlying mechanism and treat the root cause for many diseases which had been causing morbidity and mortality up until this point in human history. Furthermore, many of the standard diagnostic procedures have now been transformed to provide answers at or near the point-of-care. However, the effects of these positive developments have not trickled down to the parts of our society which are considered underdeveloped and lack the necessary infrastructure and facilities. Diagnostics in such resource limited settings still lag behind and fail to provide the requisite healthcare.
In order to translate the diagnostic solutions designed for central laboratories to resource limited settings, there are certain challenges that need to be addressed, such as portability, reduction in cost and ease-of-use, while keeping the sensitivity and specificity at the required level. The work presented in this thesis focuses on addressing some of these issues by using microfluidics to develop diagnostic platforms that are suitable to be used in resource limited settings.
In paper I, a very low-cost and simple centrifugal microfluidic platform was developed to be used in settings which do not have a reliable supply of electricity. The platform uses a smartphone as a source of power and the sensors of the phone for speed control.
In paper II, a portable and low-cost diagnostic platform was developed for multiplexed detection of biomarkers based on centrifugal microfluidics. The platform uses colorimetric detection and a simple readout method which does not require a spectrophotometer for quantification.
In paper III, a platform was developed for COVID-19 diagnostics which combines centrifugal microfluidics with a novel bead-based strategy for signal enhancement. The platform uses fluorescent detection with a smartphone readout and has the capability to process up to 20 samples at the same time.
In paper IV, as a follow up of paper III, a more advanced platform was developed for COVID-19 diagnostics which allows the operator to carry out nucleic acid amplification in a completely automated manner, from adding the sample to getting the final result.
In paper V, an alternative method for detection of SARS-CoV-2 was developed using electrochemical biosensing. This work combines the electrochemical technique with a flexible printed circuit board for a rapid, amplification-free and label-free detection of target SARS-CoV-2 sequences.