Chemistry Reference
In-Depth Information
Fig. 7.2 A prototype of a holographic paper-based micro
uidic device interpreted with a
smartphone application. a Capturing image from the assay, and b Displaying the results
fl
assays [
48
]. The app allowed automated analysis of the colorimetric tests. It utilised
the nearest neighbour problem approach to estimate the pH, protein and glucose
concentrations in arti
cial urine solutions using commercial test strips. The app
used the phone
s camera to convert colorimetric data from the assay into numerical
concentration values on the phone
'
s screen. It performed this by comparing the
colorimetric data with a pre-recorded calibration by locating the position of the
colour point data in the model and assigning it a concentration value. The app was
tested with both an Android phone and an iPhone, showing comparable accuracy.
The results can be stored, sent to a healthcare professional, or directly analysed by
the phone for diagnosis. The app allows users to collect quantitative data and
submit the results to clinicians for immediate review. By quickly getting medical
data from the
'
field to doctors or centralised laboratories can slow or limit the spread
of pandemics. Future work in this area should address automated compensation for
measurement variability (e.g. focus, angle, lighting conditions, shadow effects and
sensor type). Advanced algorithms should eventually produce actionable informa-
tion for the user while also ensuring patient safety [
49
]. Investigations of data
processing strategies and auto-compensation capabilities to mitigate errors due to
colorimetric interference will be valuable contributions to the
field. Such devel-
opments may create solutions for reducing interference from the background colour
of the samples (e.g. blood). Quantitative data processing on mobile devices such as
smartphones, tablets, smartwatches, Google Glass should enhance the compatibility
and feasibility in developing integrated holographic diagnostic devices. Figure
7.2
illustrates the prototype of an app that allows reading paper-based holographic
