A portable microfluidic system for rapid measurement of the erythrocyte sedimentation rate

The erythrocyte sedimentation rate (ESR) is a frequently used 30 min or 60 min clinical test for screening of several inflammatory conditions, infections, trauma, and malignant diseases, as well as non-inflammatory conditions including prostate cancer and stroke. Erythrocyte aggregation (EA) is a physiological process where erythrocytes form face-to-face linear structures, called rouleaux, at stasis or low shear rates. In this work, we proposed a method for ESR measurement from EA. We developed a microfluidic opto-electro-mechanical system, using which we experimentally showed a significant correlation (R2 = 0.86) between ESR and EA. The microfluidic system was shown to measure ESR from EA using fingerprick blood in 2 min. 40 μl of whole blood is filled in a disposable polycarbonate cartridge which is illuminated with a near infrared emitting diode. Erythrocytes were disaggregated under the effect of a mechanical shear force using a solenoid pinch valve. Following complete disaggregation, transmitted light through the cartridge was measured using a photodetector for 1.5 min. The intensity level is at its lowest at complete disaggregation and highest at complete aggregation. We calculated ESR from the transmitted signal profile. We also developed another microfluidic cartridge specifically for monitoring the EA process in real-time during ESR measurement. The presented system is suitable for ultrafast, low-cost, and low-sample volume measurement of ESR at the point-of-care. © The Royal Society of Chemistry

A microfluidic erythrocyte sedimentation rate analyzer using rouleaux formation kinetics

Red blood cell aggregation is an intrinsic property of red blood cells that form reversible stacked structures, also called rouleaux, under low shear rates. Erythrocyte sedimentation rate (ESR), commonly performed in clinics, is an indirect inflammation screener and a prognostic test for diseases. We have recently developed a microfluidic system for rapid measurement of ESR from 40 µl whole blood employing the aggregation dynamics. In this work, we propose the use of an aggregation inducer, dextran polyglucose, for the preparation of multiple blood samples with differing aggregation dynamics. Using these samples, we characterized the performance of the system with three aggregation indices and under varying experimental conditions. Additionally, using the same underlying principle, we improved the system for ESR measurement using both venipuncture and fingerprick whole blood samples depending on the user needs. The results demonstrate that the system performs equally well with both samples, which validates the compatibility of the system for both laboratory and point-of-care applications where venous and capillary blood are the primary samples, respectively. The detailed characterization presented in this study legitimates the feasibility of the system for ultrafast and facile measurement of ESR in clinics and diverse off-laboratory settings. © 2017, Springer-Verlag Berlin Heidelberg

Rapid fabrication of microfluidic PDMS devices from reusable PDMS molds using laser ablation

The conventional fabrication methods for microfluidic devices require cleanroom processes that are costly and time-consuming. We present a novel, facile, and low-cost method for rapid fabrication of polydimethylsiloxane (PDMS) molds and devices. The method consists of three main fabrication steps: female mold (FM), male mold (MM), and chip fabrication. We use a CO2 laser cutter to pattern a thin, spin-coated PDMS layer for FM fabrication. We then obtain reusable PDMS MM from the FM using PDMS/PDMS casting. Finally, a second casting step is used to replicate PDMS devices from the MM. Demolding of one PDMS layer from another is carried out without any potentially hazardous chemical surface treatment. We have successfully demonstrated that this novel method allows fabrication of microfluidic molds and devices with precise dimensions (thickness, width, length) using a single material, PDMS, which is very common across microfluidic laboratories. The whole process, from idea to device testing, can be completed in 1.5 h in a standard laboratory. © 2016 IOP Publishing Ltd

Microfluidic measurement of erythrocyte sedimentation rate and monitoring of erytrocyte aggregation

We developed a novel microfluidic opto-electro-mechanical system and performed ultrafast, cheap, and low-sample volume measurement of erythrocyte sedimentation rate (ESR) from erythrocyte aggregation (EA). We also showed EA dynamics in real-time during measurements

In vitro analysis of multiple blood flow determinants using red blood cell dynamics under oscillatory flow

Abstract The flow behavior of blood is determined mainly by red blood cell (RBC) deformation and aggregation as well as blood viscoelasticity. These intricately interdependent parameters should be monitored by healthcare providers to understand all aspects of circulatory flow dynamics under numerous cases including cardiovascular and infectious diseases. Current medical instruments and microfluidic systems lack the ability to quantify these parameters all at once and in physiologically relevant flow conditions. This work presents a handheld platform and a measurement method for quantitative analysis of multiple of these parameters from 50 μl undiluted blood inside a miniaturized channel. The assay is based on an optical transmission analysis of collective RBC deformation and aggregation under near-infrared illumination during a 1 s damped oscillatory flow and at stasis, respectively. Measurements with blood of different hemo-rheological properties demonstrate that the presented approach holds a potential for initiating simultaneous and routine on-chip blood flow analysis even in resource-poor settings

An in-situ fabrication technique to form integrated microelectrodes

ACS Publications, Analytical Chemistry;American Elements;Aquatech Co., Ltd and Takasago Fluidic Systems;ASK;CapitalBio Technology;et al.19th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2015 -- 25 October 2015 through 29 October 2015 -- -- 122797In this study we have developed a new fabrication method to form microelectrodes for microfluidic applications. We present a microfabrication route to achieve embedded microelectrodes within a microchannel without needing for a microfabrication facility or lithography and metallization processes. This method includes attaching a gold microwires on a glass slide and bonding PDMS micro channels perpendicular to the microwire. Then aqua regia solution is passed through the channel etching the wire inside of the channel and forming two electrodes on the two sides. We applied these electrodes to the impedance flow cytometry for high sensitive detection of polystyrene beads and red blood cells. We also compared the performance of our electrodes with the coplanar electrodes which is the most commonly used geometry of the impedance flow cytometry. The etched electrodes give up to 20 times better SNR compared to coplanar electrodes. © 15CBMS-0001

Lab-on-a-chip platforms for disease detection and diagnosis

[No abstract available

Assessment of stored red blood cells through lab-on-a-chip technologies for precision transfusion medicine

Abstract Transfusion of red blood cells (RBCs) is one of the most valuable and widespread treatments in modern medicine. Lifesaving RBC transfusions are facilitated by the cold storage of RBC units in blood banks worldwide. Currently, RBC storage and subsequent transfusion practices are performed using simplistic workflows. More specifically, most blood banks follow the “first-in-first-out” principle to avoid wastage, whereas most healthcare providers prefer the “last-in-first-out” approach simply favoring chronologically younger RBCs. Neither approach addresses recent advances through -omics showing that stored RBC quality is highly variable depending on donor-, time-, and processing-specific factors. Thus, it is time to rethink our workflows in transfusion medicine taking advantage of novel technologies to perform RBC quality assessment. We imagine a future where lab-on-a-chip technologies utilize novel predictive markers of RBC quality identified by -omics and machine learning to usher in a new era of safer and precise transfusion medicine