title: Capillary hydrodynamic chromatography reveals temporal profiles of cell aggregates.
abstract: Microbial cells are known to form aggregates. Such aggregates can be found in various matrices; for example, functional drinks. Capillary hydrodynamic chromatography (HDC) enables separation of particles by size using nanoliter-scale volumes of samples. Here we propose an approach based on HDC for characterisation of real samples containing aggregated and non-aggregated bacterial and fungal cells. Separation of cells and cell aggregates in HDC arises from the parabolic flow profile under laminar flow conditions. In the presented protocol, hydrodynamic separation is coupled with different on-line and off-line detectors (light absorption/scattering and microscopy). The method has successfully been applied in the monitoring of dynamic changes in the microbiome of probiotic drinks. Chromatographic profiles of yogurt and kefir samples obtained at different times during fermentation are in a good agreement with microscopic images. Moreover, thanks to the implementation of an area imaging detector, capillary HDC could be multiplexed and used to profile spatial gradients in cell suspensions, which arise in the course of sedimentation of cells and cell aggregates. This result shows compatibility of sedimentation analysis and capillary HDC. We believe that the approach may find applications in the profiling of functional foods and other matrices containing aggregated bioparticles.
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan.
authors.forename: Ya-Ru
authors.initials: YR
authors.lastname: Tang
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan.
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Huang
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan.
authors.forename: Jie-Bi
authors.initials: JB
authors.lastname: Hu
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Rattinam
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan.
authors.forename: Chun-Hsien
authors.initials: CH
authors.lastname: Li
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan; Institute of Molecular Science, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan.
authors.forename: Yu-Chie
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan; Institute of Molecular Science, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan. Electronic address: plurban@nctu.edu.tw.
authors.forename: Pawel L
authors.initials: PL
authors.lastname: Urban
mesh_terms: D001419:Bacteria / Q000254:growth & development; D001628:Beverages / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods*; D003611:Dairy Products / Q000032:analysis*; D005285:Fermentation; D057446:Hydrodynamics; D019936:Probiotics
keywords: Aggregation; Cell suspension; Functional food; Hydrodynamic chromatography; Microbiome; Sedimentation analysis