title: Efficient removal of platelets from peripheral blood progenitor cell products using a novel micro-chip based acoustophoretic platform.
abstract: BACKGROUND
  Excessive collection of platelets is an unwanted side effect in current centrifugation-based peripheral blood progenitor cell (PBPC) apheresis. We investigated a novel microchip-based acoustophoresis technique, utilizing ultrasonic standing wave forces for the removal of platelets from PBPC products. By applying an acoustic standing wave field onto a continuously flowing cell suspension in a micro channel, cells can be separated from the surrounding media depending on their physical properties.
  
  
  METHODS
  PBPC samples were obtained from patients (n = 15) and healthy donors (n = 6) and sorted on an acoustophoresis-chip. The acoustic force was set to separate leukocytes from platelets into a target fraction and a waste fraction, respectively. The PBPC samples, the target and the waste fractions were analysed for cell recovery, purity and functionality.
  
  
  RESULTS
  The median separation efficiency of leukocytes to the target fraction was 98% whereas platelets were effectively depleted by 89%. PBPC samples and corresponding target fractions were similar in the percentage of CD34+ hematopoetic progenitor/stem cells as well as leukocyte/lymphocyte subset distributions. Median viability was 98%, 98% and 97% in the PBPC samples, the target and the waste fractions, respectively. Results from hematopoietic progenitor cell assays indicated a preserved colony-forming ability post-sorting. Evaluation of platelet activation by P-selectin (CD62P) expression revealed a significant increase of CD62P+ platelets in the target (19%) and waste fractions (20%), respectively, compared to the PBPC input samples (9%). However, activation was lower when compared to stored blood bank platelet concentrates (48%).
  
  
  CONCLUSIONS
  Acoustophoresis can be utilized to efficiently deplete PBPC samples of platelets, whilst preserving the target stem/progenitor cell and leukocyte cell populations, cell viability and progenitor cell colony-forming ability. Acoustophoresis is, thus, an interesting technology to improve current cell processing methods.
authors.affiliation: Clinical Immunology and Transfusion Medicine, Regional and University Laboratories, Lund, Sweden. josefina.dykes@med.lu.se
authors.forename: Josefina
authors.initials: J
authors.lastname: Dykes
authors.forename: Andreas
authors.initials: A
authors.lastname: Lenshof
authors.forename: Ing-Britt
authors.initials: IB
authors.lastname: Åstrand-Grundström
authors.forename: Thomas
authors.initials: T
authors.lastname: Laurell
authors.forename: Stefan
authors.initials: S
authors.lastname: Scheding
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D001792:Blood Platelets / Q000166:cytology* / Q000378:metabolism; D003114:Colony-Forming Units Assay; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007937:Leukapheresis / Q000295:instrumentation* / Q000379:methods*; D007962:Leukocytes / Q000166:cytology; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D019007:P-Selectin / Q000097:blood; D015539:Platelet Activation; D010976:Platelet Count; D015203:Reproducibility of Results
chemical_list: D019007:P-Selectin