{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:03:32Z","timestamp":1785402212063,"version":"3.56.0"},"reference-count":49,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T00:00:00Z","timestamp":1783468800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Turkish Ministry of National Education"},{"id":[{"id":"https:\/\/ror.org\/00jga9g46","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Measuring platelet function is important for patient stratification to judge bleeding vs. thrombotic risk and for research into antiplatelet drugs to prevent cardiovascular disease. Variability in platelet function is not fully understood, and large studies of inter-individual variation are making gradual progress using laboratory measurements, but rapid and high-performance hematological tests are also needed. We present here a novel microfluidic technology for platelet function analysis that images light scatter by platelets, using a low-cost, open-source, high-throughput and customizable darkfield imaging system called Dark-Pi. The hardware consists of a camera and a simple LED light source controlled by a Raspberry Pi, with 3D-printed parts. Using the Dark-Pi, platelet aggregation was imaged within adenosine 5\u2032-diphosphate-loaded microcapillaries, revealing clearly visible patterns. This darkfield cellular light scatter approach was previously developed for bacterial cells, and here we adapted and optimized it for directly monitoring platelet aggregation. Capturing high-quality time-resolved images of platelets undergoing activation within microcapillaries allowed us to measure changes in light scattering in platelet-rich plasma that correspond with aggregation measured using conventional laboratory methods. This novel prototype system shows that this approach may have potential for use in large-scale studies of platelet function, combining simplicity with low-cost components and using a disposable dip-and-test microfluidic format.<\/jats:p>","DOI":"10.3390\/s26144326","type":"journal-article","created":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T16:16:18Z","timestamp":1783527378000},"page":"4326","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Dark-Pi Imaging System Permits Open-Source Label-Free Microfluidic Monitoring of Platelet Aggregation by Cellular Light Scattering"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2155-653X","authenticated-orcid":false,"given":"R\u00fcya Meltem","family":"Sar\u0131yer Oglago","sequence":"first","affiliation":[{"name":"Department of Healthcare Management, K\u00fctahya Health Sciences University, Germiyan Campus, K\u00fctahya 43100, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2061-2253","authenticated-orcid":false,"given":"Alexander P.","family":"Bye","sequence":"additional","affiliation":[{"name":"Reading School of Pharmacy, University of Reading, Whiteknights Campus, Reading RG6 6AD, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8439-0055","authenticated-orcid":false,"given":"Sultan \u0130layda","family":"D\u00f6nmez Ery\u0131lmaz","sequence":"additional","affiliation":[{"name":"Department of Genetics and Bioengineering, Rafet Kay\u0131\u015f Engineering Faculty, Alanya Alaaddin Keykubat University, Alanya 07425, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chris I.","family":"Jones","sequence":"additional","affiliation":[{"name":"Reading School of Biological Sciences, University of Reading, Whiteknights Campus, Reading RG6 6AS, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2369-989X","authenticated-orcid":false,"given":"Alexander D.","family":"Edwards","sequence":"additional","affiliation":[{"name":"Reading School of Pharmacy, University of Reading, Whiteknights Campus, Reading RG6 6AD, UK"},{"name":"School of Electronics and Computer Science, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Gianazza, E., Brioschi, M., Baetta, R., Mallia, A., Banfi, C., and Tremoli, E. (2020). Platelets in Healthy and Disease States: From Biomarkers Discovery to Drug Targets Identification by Proteomics. Int. J. Mol. Sci., 21.","DOI":"10.3390\/ijms21124541"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1055\/s-2005-916671","article-title":"Platelets: Physiology and Biochemistry","volume":"31","author":"Jurk","year":"2005","journal-title":"Semin. Thromb. Hemost."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3","DOI":"10.21037\/aob.2019.01.02","article-title":"Novel Approaches to Quality Control and External Quality Assessment for Platelet Function Testing with a Focus on the Platelet Function Analyser (PFA-100 and PFA-200)","volume":"4","author":"Favaloro","year":"2019","journal-title":"Ann. Blood"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Alessi, M.-C., Si\u00e9, P., and Payrastre, B. (2020). Strengths and Weaknesses of Light Transmission Aggregometry in Diagnosing Hereditary Platelet Function Disorders. J. Clin. Med., 9.","DOI":"10.3390\/jcm9030763"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"4707","DOI":"10.1039\/D1LC00708D","article-title":"Fully Automated Light Transmission Aggregometry on a Disc for Platelet Function Tests","volume":"21","author":"Kim","year":"2021","journal-title":"Lab Chip"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"927","DOI":"10.1038\/194927b0","article-title":"Aggregation of Blood Platelets by Adenosine Diphosphate and Its Reversal","volume":"194","author":"Born","year":"1962","journal-title":"Nature"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"140","DOI":"10.1136\/jcp.14.2.140","article-title":"The Adhesiveness of Native Platelets and Its Prevention","volume":"14","year":"1961","journal-title":"J. Clin. Pathol."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Le Blanc, J., Mullier, F., Vayne, C., and Lordkipanidz\u00e9, M. (2020). Advances in Platelet Function Testing\u2014Light Transmission Aggregometry and Beyond. J. Clin. Med., 9.","DOI":"10.3390\/jcm9082636"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"650","DOI":"10.1080\/09537104.2018.1445838","article-title":"96-Well Plate-Based Aggregometry","volume":"29","author":"Chan","year":"2018","journal-title":"Platelets"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1111\/j.1365-2141.2011.08793.x","article-title":"Guidelines for the Laboratory Investigation of Heritable Disorders of Platelet Function","volume":"155","author":"Harrison","year":"2011","journal-title":"Br. J. Haematol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1309\/Y9EC63RW3XG1V313","article-title":"Platelet Aggregation Testing in Platelet-Rich Plasma Description of Procedures With the Aim to Develop Standards in the Field","volume":"123","author":"Zhou","year":"2005","journal-title":"Am. J. Clin. Pathol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s11239-020-02170-z","article-title":"Point-of-Care Platelet Function Tests: Relevance to Arterial Thrombosis and Opportunities for Improvement","volume":"51","author":"Gorog","year":"2021","journal-title":"J. Thromb. Thrombolysis"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"133","DOI":"10.2147\/VHRM.S44469","article-title":"Platelet Function Tests: A Comparative Review","volume":"11","author":"Paniccia","year":"2015","journal-title":"Vasc. Health Risk Manag."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"e002094","DOI":"10.1161\/JAHA.115.002094","article-title":"Platelet Function Tests: Why They Fail to Guide Personalized Antithrombotic Medication","volume":"4","author":"Gorog","year":"2015","journal-title":"J. Am. Heart Assoc."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2427745","DOI":"10.1080\/09537104.2024.2427745","article-title":"Light Transmission Aggregometry for Platelet Function Testing: Position Paper on Current Recommendations and French Proposals for Accreditation","volume":"35","author":"Fischer","year":"2024","journal-title":"Platelets"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"20200183","DOI":"10.1002\/VIW.20200183","article-title":"Microfluidic Systems toward Blood Hemostasis Monitoring and Thrombosis Diagnosis: From Design Principles to Micro\/Nano Fabrication Technologies","volume":"3","author":"Xu","year":"2022","journal-title":"View"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4257","DOI":"10.1038\/ncomms5257","article-title":"Identification of Platelet Function Defects by Multi-Parameter Assessment of Thrombus Formation","volume":"5","author":"Swieringa","year":"2014","journal-title":"Nat. Commun."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1016\/j.thromres.2021.04.014","article-title":"Multiparameter Microfluidics Assay of Thrombus Formation Reveals Increased Sensitivity to Contraction and Antiplatelet Agents at Physiological Temperature","volume":"203","author":"Herfs","year":"2021","journal-title":"Thromb. Res."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Roka-Moiia, Y., Bozzi, S., Ferrari, C., Mantica, G., Dimasi, A., Rasponi, M., Santoleri, A., Scavone, M., Consolo, F., and Cattaneo, M. (2020). The MICELI (MICrofluidic, ELectrical, Impedance): Prototyping a Point-of-Care Impedance Platelet Aggregometer. Int. J. Mol. Sci., 21.","DOI":"10.3390\/ijms21041174"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Yoon, I., Han, J.H., and Jeon, H.-J. (2024). Advances in Platelet-Dysfunction Diagnostic Technologies. Biomolecules, 14.","DOI":"10.3390\/biom14060714"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Kang, M., Bresette, C.A., and Ku, D.N. (2024). Advancing Microfluidic Point-of-Care Platelet Function Tests: Opportunities and Challenges from Bench to Market. Front. Bioeng. Biotechnol., 12.","DOI":"10.3389\/fbioe.2024.1507972"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"128645","DOI":"10.1016\/j.snb.2020.128645","article-title":"Label-Free Smartphone Quantitation of Bacteria by Darkfield Imaging of Light Scattering in Fluoropolymer Micro Capillary Film Allows Portable Detection of Bacteriophage Lysis","volume":"323","author":"Needs","year":"2020","journal-title":"Sens. Actuators B Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"959","DOI":"10.1039\/C6AN02622B","article-title":"Covalent Immobilisation of Antibodies in Teflon-FEP Microfluidic Devices for the Sensitive Quantification of Clinically Relevant Protein Biomarkers","volume":"142","author":"Pivetal","year":"2017","journal-title":"Analyst"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"8414","DOI":"10.1039\/C5CC01559F","article-title":"A Novel Microfluidic Approach for Extremely Fast and Efficient Photochemical Transformations in Fluoropolymer Microcapillary Films","volume":"51","author":"Reis","year":"2015","journal-title":"Chem. Commun."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1623","DOI":"10.1039\/D3SD00162H","article-title":"Time- and Distance-Resolved Robotic Imaging of Fluid Flow in Vertical Microfluidic Strips: A New Technique for Quantitative, Multiparameter Measurement of Global Haemostasis","volume":"2","author":"Gill","year":"2023","journal-title":"Sens. Diagn."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1531","DOI":"10.1016\/S0140-6736(00)02175-9","article-title":"Platelets","volume":"355","author":"George","year":"2000","journal-title":"Lancet"},{"key":"ref_27","first-page":"36","article-title":"Image Processing with ImageJ","volume":"11","author":"Abramoff","year":"2004","journal-title":"Biophotonics Int."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"e022125","DOI":"10.1161\/JAHA.121.022125","article-title":"Cangrelor: Clinical Data, Contemporary Use, and Future Perspectives","volume":"10","author":"Steg","year":"2021","journal-title":"J. Am. Heart Assoc."},{"key":"ref_29","first-page":"426","article-title":"Detection of Platelet Aggregates Using Light Scattering","volume":"43","author":"Satoh","year":"1995","journal-title":"Rinsho Byori Jpn. J. Clin. Pathol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"174","DOI":"10.1088\/0957-0233\/6\/2\/008","article-title":"A Laser Light Scattering in Situ System for Counting Aggregates in Blood Platelet Aggregation","volume":"6","author":"Yamamoto","year":"1995","journal-title":"Meas. Sci. Technol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1016\/S0008-6363(98)00114-X","article-title":"Platelet Aggregation in Acute Coronary Syndromes: Use of a New Aggregometer with Laser Light Scattering to Assess Platelet Aggregability","volume":"40","author":"Eto","year":"1998","journal-title":"Cardiovasc. Res."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"515","DOI":"10.1016\/0049-3848(96)00026-6","article-title":"Factors That Affect the Size of Platelet Aggregates in Epinephrine-Induced Activation: A Study Using the Particle Counting Method Based upon Light Scattering","volume":"81","author":"Satoh","year":"1996","journal-title":"Thromb. Res."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1016\/S0049-3848(98)00138-8","article-title":"A New System to Detect Native Microaggregates of Platelets In Vivo, with a Novel Platelet Aggregometer Employing Laser Light Scattering","volume":"92","author":"Tomida","year":"1998","journal-title":"Thromb. Res."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"437","DOI":"10.1007\/0-306-48382-3_89","article-title":"Spontaneous Platelet Aggregation in Patients with Beh\u00e7et\u2019s Disease by Using Laser-Light Scattering Aggregometer","volume":"Volume 528","author":"Zouboulis","year":"2004","journal-title":"Adamantiades-Beh\u00e7et\u2019s Disease"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"719","DOI":"10.1046\/j.1525-1594.2001.06863.x","article-title":"Platelet Damage Caused by the Centrifugal Pump: Laser-Light Scattering Analysis of Aggregation Patterns","volume":"25","author":"Tanaka","year":"2001","journal-title":"Artif. Organs"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1067\/mlc.2003.4","article-title":"Laser-Light Scattering, a New Method for Continuous Monitoring of Platelet Activation in Circulating Fluid","volume":"141","author":"Abela","year":"2003","journal-title":"J. Lab. Clin. Med."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Han, J.H., Yoon, I., and Jeon, H.-J. (2024). Microfluidic System-Based Quantitative Analysis of Platelet Function through Speckle Size Measurement. Biomolecules, 14.","DOI":"10.3390\/biom14060612"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"9067","DOI":"10.1038\/s41467-024-53069-9","article-title":"Multi-Parametric Thrombus Profiling Microfluidics Detects Intensified Biomechanical Thrombogenesis Associated with Hypertension and Aging","volume":"15","author":"Din","year":"2024","journal-title":"Nat. Commun."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.mex.2018.12.012","article-title":"Platelet Aggregometry Assay for Evaluating the Effects of Platelet Agonists and Antiplatelet Compounds on Platelet Function in Vitro","volume":"6","author":"Tsoupras","year":"2019","journal-title":"MethodsX"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1183","DOI":"10.1111\/jth.12231","article-title":"Recommendations for the Standardization of Light Transmission Aggregometry: A Consensus of the Working Party from the Platelet Physiology Subcommittee of SSC\/ISTH","volume":"11","author":"Cattaneo","year":"2013","journal-title":"J. Thromb. Haemost."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1016\/j.blre.2004.05.002","article-title":"Platelet Function Analysis","volume":"19","author":"Harrison","year":"2005","journal-title":"Blood Rev."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1016\/j.hoc.2013.03.003","article-title":"Testing Platelet Function","volume":"27","author":"Harrison","year":"2013","journal-title":"Hematol. Oncol. Clin. N. Am."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1039\/B916757A","article-title":"A Microfluidics Device to Monitor Platelet Aggregation Dynamics in Response to Strain Rate Micro-Gradients in Flowing Blood","volume":"10","author":"Rosengarten","year":"2010","journal-title":"Lab Chip"},{"key":"ref_44","first-page":"98","article-title":"A Microfluidic Device for Platelet Aggregation Assay","volume":"229","author":"Guo","year":"2015","journal-title":"Proc. Inst. Mech. Eng. Part N J. Nanoeng. Nanosyst."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"2363","DOI":"10.1182\/blood.V122.21.2363.2363","article-title":"Clot-On-A-Chip: A Microfluidic Device To Study Platelet Aggregation and Contractility Under Shear","volume":"122","author":"Ting","year":"2013","journal-title":"Blood"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"5574413","DOI":"10.1155\/2021\/5574413","article-title":"Application of a Simple Microfluidic Chip Analysis Technology to Evaluate the Inhibitory Role of Protocatechuic Acid on Shear-Induced Platelet Aggregation","volume":"2021","author":"He","year":"2021","journal-title":"Evid.-Based Complement. Altern. Med."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1002\/bem.21785","article-title":"Does the Magnetic Field of a Magnetic Stirrer in an Optical Aggregometer Affect Concurrent Platelet Aggregation?","volume":"34","author":"Sagdilek","year":"2013","journal-title":"Bioelectromagnetics"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Albers, H., Passier, R., van den Berg, A., and van der Meer, A. (2019). Automated Analysis of Platelet Aggregation on Cultured Endothelium in a Microfluidic Chip Perfused with Human Whole Blood. Micromachines, 10.","DOI":"10.3390\/mi10110781"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1016\/j.mvr.2011.11.007","article-title":"A Microchip Flow-Chamber System for Quantitative Assessment of the Platelet Thrombus Formation Process","volume":"83","author":"Hosokawa","year":"2012","journal-title":"Microvasc. Res."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/14\/4326\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T16:18:13Z","timestamp":1783527493000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/14\/4326"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,8]]},"references-count":49,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2026,7]]}},"alternative-id":["s26144326"],"URL":"https:\/\/doi.org\/10.3390\/s26144326","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,8]]}}}