We have been developing systems for point-of-care detection of disorders related with inflammation, coagulopathy and newborn jaundice. The development of such systems requires combination of new scientific methods together with engineering approaches from mechanical and electrical engineering. Our group has expertise in development of handheld prototypes as well as disposable cartridges. The ideal point-of-care product works with single use low-cost cartridges. Below are some examples from our research work.
Portable microfluidic system for rapid measurement of erythrocyte sedimentation rate (Z. Isiksacan et. al. 2016)
We developed a microfluidic system that measures erythrocyte sedimentation rate (ESR) from erythrocyte aggregation using only 40 μl of whole blood in 2 min. The system consists of a disposable single-channel polycarbonate cartridge and a handheld opto-electro-mechanical analyzer. The test cycle starts off by completely disaggregating erythrocytes in the cartridge using a rigorous back and forth fluid motion generated by a solenoid pinch valve. Then, the fluid motion is ceased, and cells start to aggregate. During this aggregation phase, optically transmitted through the cartridge is measured for 1.5 min. Then, the ESR value is calculated using the optical signal change. For experimental verification of the microfluidic system and the measurement method, whole blood samples of 70 patients were tested with our system. The microfluidic system was shown to correlate with the conventional Westergren method with %86 using linear regression. Designing another unique cartridge, we were able to demonstrate the one-to-one correspondence between the aggregation of erythrocytes and the optical transmission signal. This microfluidic system is of high value for ultrafast point-of-care ESR measurement, which requires only a drop of whole blood.
We devised a surface plasmon resonance (SPR) imaging system integrated to a smartphone. We have developed very low-cost grating coupled SPR sensor chips using off-the-shelf optical storage discs. Additionally, we designed a compact optical system, using a 3D-printed apparatus that hosts the LED source, collimator, bandpass filter, linear polarizer, beamsplitter plate and an external imaging lens which can be easily attached to the smartphone. We employed a silver/gold (Ag/Au) bilayer structure coated on the periodic corrugations of Blu-ray discs in order to perform plasmon resonance imaging at the central region of visible spectrum under normal incidence illumination in aqueous environment. This allowed the optimal use of the CMOS sensor of the smartphone whilemaintaining high sensitivity, chemical stability and biological affinity. A microfluidic channel is placed on the bimetallic layer for controlled plumbing of the liquids. The use of Blu-ray discs and standard metal deposition techniques together with the low-cost microfluidic channel resulted in significant cost-reduction which can allow the system to be used for applications requiring disposable SPR sensors.
A point-of-care device for newborn jaundice monitoring (unpublished)
We are working on a handheld system for rapid detection of total serum bilirubin from capillary blood for effective monitoring of newborn jaundice. Jaundice is very commonly seen in newborns and may lead to brain damage if not treated. Although treatment of jaundice is relatively straightforward, it is a pity that the newborns need to be kept at emergency departments during treatment at the first few days of their lives. In the current practice, the bilirubin level of the newborn is measured mostly using photometric devices which require a tube of blood and plasma separation. We are developing a technology that can separate plasma from whole blood and measure total serum bilirubin using only 15 ul of whole blood sample in 2 minutes. Stay tuned for more results…