title: Microfluidic processing of synovial fluid for cytological analysis.
abstract: Cytological analysis of synovial fluid is widely used in the clinic to assess joint health and disease. However, in general practice, only the total number of white blood cells (WBCs) are available for cytologic evaluation of the joint. Moreover, sufficient volume of synovial aspirates is critical to run conventional analyses, despite limited volume of aspiration that can normally be obtained from a joint. Therefore, there is a lack of consistent and standardized synovial fluid cytological tests in the clinic. To address these shortcomings, we developed a microfluidic platform (Synovial Chip), for the first time in the literature, to achieve repeatable, cost- and time-efficient, and standardized synovial fluid cytological analysis based on specific cell surface markers. Microfluidic channels functionalized with antibodies against specific cell surface antigens are connected in series to capture WBC subpopulations, including CD4+, CD8+, and CD66b+ cells, simultaneously from miniscule volumes (100 μL) of synovial fluid aspirates. Cell capture specificity was evaluated by fluorescent labeling of isolated cells in microchannels and was around 90% for all three WBC subpopulations. Furthermore, we investigated the effect of synovial fluid viscosity on capture efficiency in the microfluidic channels and utilized hyaluronidase enzyme treatment to reduce viscosity and to improve cell capture efficiency (>60%) from synovial fluid samples. Synovial Chip allows efficient and standardized point-of-care isolation and analysis of WBC subpopulations in miniscule volumes of patient synovial fluid samples in the clinic.
authors.affiliation: Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA.|Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Krebs
authors.affiliation: Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA.|Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany.
authors.forename: Yunus
authors.initials: Y
authors.lastname: Alapan
authors.affiliation: Department of Orthopaedic Surgery, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Dennstedt
authors.affiliation: Department of Orthopaedic Surgery, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA.|Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA.|Department of Orthopaedics, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Wera
authors.affiliation: Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA. umut@case.edu.|Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA. umut@case.edu.|Department of Orthopaedics, Case Western Reserve University, Cleveland, OH, USA. umut@case.edu.|Biomedical Engineering Department, Case Western Reserve University, Cleveland, OH, USA. umut@case.edu.
authors.forename: Umut A
authors.identifier: 0000-0002-0331-9960
authors.initials: UA
authors.lastname: Gurkan
mesh_terms: D003584:Cytological Techniques / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D056656:Lab-On-A-Chip Devices; D013582:Synovial Fluid / Q000166:cytology*; D014783:Viscosity
keywords: Cell isolation; Joint health; Lab-on-a-chip systems; Point-of-care testing; White blood cells