Smartphone interfaced image based creatinine estimation on a novel micro pipette tip-based platform: Whole blood...

The rapid advancement of point-of-care diagnostic devices highlight different microfluidic platforms which have emerged special popularity due to their low-cost, portability, ready-to-use and easy-handling nature with the involvement of minimally skilled human resources. We envisage the development of a novel micro pipette-tip based platform for creatinine readout from whole blood sample-in and answer-out via single clinical assay using finger-pricked blood. A portable pipette-tip-based microfluidic diagnostic platform is presented for rapid on-device plasma separation and colorimetric detection of creatinine using a smartphone-interfaced analysis system. The platform integrates a hybrid solar/AC-operated mini-centrifuge that enables efficient plasma extraction from just 32 μL of finger-prick whole blood, eliminating the need for conventional laboratory infrastructure. The separated plasma subsequently reacts with alkaline 3,5-dinitrobenzoic acid within the same pipette-tip cartridge, producing a stable colored complex within 10 min through a non-enzymatic detection pathway. The resulting chromogenic signal is captured using a smartphone camera and analyzed through a custom application that extracts RGB intensity values to yield quantitative creatinine concentrations in milligrams per deciliter (mg/dL). A limit of detection has been found approximately as 0.16 mg/dL with lower limit of quantification as 0.52 mg/dL. The test kit shows excellent agreement with gold standard results. Moreover, this device has also been integrated with high purity blood-plasma separation. Hence, this low-cost micro-pipet tip-based platform provides colorimetry based final creatinine read-out from whole blood sample-in, answer-out format via single go with uncompromised accuracy which can easily be deployed in field-setting as a true point-of-care diagnostic tool.