title: Trapping cells in paper for white blood cell count.
abstract: White blood cell count is an important indicator of each individual's health condition. An abnormal white blood cell count usually results from an infection, cancer, or other conditions that trigger systemic inflammation responses. White blood cell count also provides predictive information on the incidence of cardiovascular diseases and Type 2 diabetes. Therefore, monitoring white blood cell count on a regular basis can potentially help individuals to take preventive measures and improve healthcare outcomes. Currently, white blood cell count is primarily conducted in centralized laboratories, and it requires specialized equipment and dedicated personnel to perform the test and interpret the results. So far there has been no rapid test that allows white blood cell count in low-resource settings. In this study, we have demonstrated a vertical flow platform that quantifies white blood cells by trapping them in the paper. White blood cells were tagged with gold nanoparticles, and flowed through the paper via a small orifice. The white blood cell count was determined by measuring the colorimetric intensity of gold nanoparticles on the surface of white blood cells that were trapped in the paper mesh. Using this platform, we were able to quantify white blood cells in 15 μL of blood, and visually differentiate the abnormal count of white blood cells from the normal count. The proposed platform enabled rapid white blood cell count in low resource settings with a small sample volume requirement. Its low-cost, instrument-free operations would be attractive for point-of-care applications.
authors.affiliation: Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore.
authors.forename: Jianhao
authors.initials: J
authors.lastname: Bai
authors.affiliation: Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore.
authors.forename: Hong
authors.initials: H
authors.lastname: Wu
authors.affiliation: Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore. Electronic address: jyying@ibn.a-star.edu.sg.
authors.forename: Jackie Y
authors.initials: JY
authors.lastname: Ying
mesh_terms: D002469:Cell Separation / Q000295:instrumentation*; D003124:Colorimetry / Q000295:instrumentation*; D004209:Disposable Equipment; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007958:Leukocyte Count / Q000295:instrumentation*; D007962:Leukocytes / Q000166:cytology*; D010209:Paper; D011934:Reagent Strips; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D011934:Reagent Strips
keywords: Flow-through; Gold nanoparticle; Immunoassay; Paper microfluidics; Vertical flow; White blood cell count