Browsing by Author "Xia, Hui"
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Item A high-throughput microfluidic approach for 1000-fold leukocyte reduction of platelet-rich plasma(Scientific Reports, 10/24/2016) Xia, Hui; Strachan, Briony C.; Gifford, Sean C.; Shevkoplyas, Sergey S.Leukocyte reduction of donated blood products substantially reduces the risk of a number of transfusion-related complications. Current ‘leukoreduction’ filters operate by trapping leukocytes within specialized filtration material, while allowing desired blood components to pass through. However, the continuous release of inflammatory cytokines from the retained leukocytes, as well as the potential for platelet activation and clogging, are significant drawbacks of conventional ‘dead end’ filtration. To address these limitations, here we demonstrate our newly-developed ‘controlled incremental filtration’ (CIF) approach to perform high-throughput microfluidic removal of leukocytes from platelet-rich plasma (PRP) in a continuous flow regime. Leukocytes are separated from platelets within the PRP by progressively syphoning clarified PRP away from the concentrated leukocyte flowstream. Filtrate PRP collected from an optimally-designed CIF device typically showed a ~1000-fold (i.e. 99.9%) reduction in leukocyte concentration, while recovering >80% of the original platelets, at volumetric throughputs of ~1?mL/min. These results suggest that the CIF approach will enable users in many fields to now apply the advantages of microfluidic devices to particle separation, even for applications requiring macroscale flowrates.Item A portable system for processing donated whole blood into high quality components without centrifugation(PLoS One, 1/18/2018) Gifford, Sean C.; Strachan, Briony C.; Xia, Hui; Vörös, Eszter; Torabian, Kian; Tomasino, Taylor A.; Griffin, Gary D.; Lichtiger, Benjamin; Aung, Fleur M.; Shevkoplyas, Sergey S.Background The use of centrifugation-based approaches for processing donated blood into components is routine in the industrialized world, as disparate storage conditions require the rapid separation of ‘whole blood’ into distinct red blood cell (RBC), platelet, and plasma products. However, the logistical complications and potential cellular damage associated with centrifugation/apheresis manufacturing of blood products are well documented. The objective of this study was to evaluate a proof-of-concept system for whole blood processing, which does not employ electromechanical parts, is easily portable, and can be operated immediately after donation with minimal human labor. Methods and findings In a split-unit study (n = 6), full (~500mL) units of freshly-donated whole blood were divided, with one half processed by conventional centrifugation techniques and the other with the new blood separation system. Each of these processes took 2–3 hours to complete and were performed in parallel. Blood products generated by the two approaches were compared using an extensive panel of cellular and plasma quality metrics. Comparison of nearly all RBC parameters showed no significant differences between the two approaches, although the portable system generated RBC units with a slight but statistically significant improvement in 2,3-diphosphoglyceric acid concentration (p < 0.05). More notably, several markers of platelet damage were significantly and meaningfully higher in products generated with conventional centrifugation: the increase in platelet activation (assessed via P-selectin expression in platelets before and after blood processing) was nearly 4-fold higher for platelet units produced via centrifugation, and the release of pro-inflammatory mediators (soluble CD40-ligand, thromboxane B2) was significantly higher for centrifuged platelets as well (p < 0.01). Conclusion This study demonstrated that a simple, passive system for separating donated blood into components may be a viable alternative to centrifugation—particularly for applications in remote or resource-limited settings, or for patients requiring highly functional platelet product.Item Towards bedside washing of stored red blood cells: a prototype of a simple apparatus based on microscale sedimentation in normal gravity(Vox Sanguinis, 1/1/2019) Khanal, Grishma; Huynh, R.A.; Torabian, Kian; Xia, Hui; Vörös, Eszter; Shevkoplyas, Sergey S.Background and ObjectivesInfusion of by?products of red blood cell (RBC) storage?induced degradation as well as of the residual plasma proteins and the anticoagulant?preservative solution contained in units of stored blood serve no therapeutic purpose and may be harmful to some patients. Here, we describe a prototype of a gravity?driven system for bedside washing of stored RBCs. Materials and Methods Stored RBCs were diluted to 10% haematocrit (Hct) with normal saline, matching the conventional washing procedure. The dilute RBC suspensions were passed through a column of coiled tubing to allow RBC sedimentation in normal gravity, thus separating them from the washing solution. Washed RBCs were collected using bifurcations located along the tubing. Washing efficiency was quantified by measuring Hct, morphology, deformability, free haemoglobin and total?free protein. Results The gravity?driven washing system operating at 0·5 ml/min produced washed RBCs with final Hct of 36·7 ± 3·4% (32·3–41·2%, n = 10) and waste Hct of 3·4 ± 0·7% (2·4–4·3%, n = 10), while removing 80% of free haemoglobin and 90% of total?free protein. Washing improved the ability of stored RBCs to perfuse an artificial microvascular network by 20%. The efficiency of washing performed using the gravity?driven system was not significantly different than that of conventional centrifugation. Conclusions This proof?of?concept study demonstrates the feasibility of washing stored RBCs using a simple, disposable system with efficiency comparable to that of conventional centrifugation, and thus represents a significant first step towards enabling low?cost washing of stored blood at bedside.Item Washing in hypotonic saline reduces the fraction of irreversibly-damaged cells in stored blood: a proof-of-concept study(Blood Transfusion, 2017-09) Xia, Hui; Khanal, Grishma; Strachan, Briony C.; Vörös, Eszter; Piety, Nathaniel Z.; Gifford, Sean C.; Shevkoplyas, Sergey S.Background During hypothermic storage, a substantial fraction of red blood cells (RBCs) transforms from flexible discocytes to rigid sphero-echinocytes and spherocytes. Infusion of these irreversibly-damaged cells into the recipient during transfusion serves no therapeutic purpose and may contribute to adverse outcomes in some patients. In this proof-of-concept study we describe the use of hypotonic washing for selective removal of the irreversibly-damaged cells from stored blood. Materials and methods Stored RBCs were mixed with saline of various concentrations to identify optimal concentration for inducing osmotic swelling and selective bursting of spherical cells (sphero-echinocytes, spherocytes), while minimising indiscriminate lysis of other RBCs. Effectiveness of optimal treatment was assessed by measuring morphology, rheological properties, and surface phosphatidylserine (PS) exposure for cells from several RBCs units (n=5, CPD>AS-1, leucoreduced, 6 weeks storage duration) washed in hypotonic vs isotonic saline. Results Washing in mildly hypotonic saline (0.585 g/dL, osmolality: 221.7±2.3 mmol/kg) reduced the fraction of spherical cells 3-fold from 9.5±3.4% to 3.2±2.8%, while cutting PS exposure in half from 1.48±0.86% to 0.59±0.29%. Isotonic washing had no effect on PS exposure or the fraction of spherical cells. Both isotonic and hypotonic washing increased the fraction of well-preserved cells (discocytes, echinocytes 1) substantially, and improved the ability of stored RBCs to perfuse an artificial microvascular network by approximately 25%, as compared with the initial sample. Discussion This study demonstrated that washing in hypotonic saline could selectively remove a significant fraction of the spherical and PS-exposing cells from stored blood, while significantly improving the rheological properties of remaining well-preserved RBCs. Further studies are needed to access the potential effect from hypotonic washing on transfusion outcomes.