Validity of Three-Dimensional Tortuous Pore Structure and Fouling of Hemoconcentration Capillary Membrane Using the Tortuous Pore Diffusion Model and Scanning Probe Microscopy

Hemoconcentration membranes used in cardiopulmonary bypass require a pore structure design with high pure water permeability, which does not allow excessive protein adsorption and useful protein loss. However, studies on hemoconcentration membranes have not been conducted yet. The purpose of this study was to analyze three-dimensional pore structures and protein fouling before and after blood contact with capillary membranes using the tortuous pore diffusion model and a scanning probe microscope system. We examined two commercially available capillary membranes of similar polymer composition that are successfully used in hemoconcentration clinically. Assuming the conditions of actual use in cardiopulmonary bypass, bovine blood was perfused inside the lumens of these membranes. Pure water permeability before and after bovine blood perfusion was measured using dead-end filtration. The scanning probe microscopy system was used for analysis. High-resolution three-dimensional pore structures on the inner surface of the membranes were observed before blood contact. On the other hand, many pore structures after blood contact could not be observed due to protein fouling. The pore diameters calculated by the tortuous pore diffusion model and scanning probe microscopy were mostly similar and could be validated reciprocally. Achievable pure water permeabilities showed no difference, despite protein fouling on the pore inlets (membrane surface). In addition, low values of albumin sieving coefficient are attributable to protein fouling that occurs on the membrane surface. Therefore, it is essential to design the membrane structure that provides the appropriate control of fouling. The characteristics of the hemoconcentration membranes examined in this study are suitable for clinical use.

Download Full-text

Validity of Three-Dimensional Tortuous Pore Structure and Fouling of Hemoconcentration Capillary Membrane Using the Tortuous Pore Diffusion Model and Scanning Probe Microscopy

10.20944/preprints202008.0157.v1 ◽

2020 ◽

Author(s):

Makoto Fukuda ◽

Hiroki Yoshinoto ◽

Hitoshi Saomoto ◽

Kiyotaka Sakai

Keyword(s):

Diffusion Model ◽

Scanning Probe Microscopy ◽

Pure Water ◽

Three Dimensional ◽

Pore Diffusion ◽

Scanning Probe ◽

Probe Microscopy ◽

Protein Fouling ◽

Pore Structures ◽

Pore Diffusion Model

Hemoconcentration membranes used in cardiopulmonary bypass require a pore structure design with high pure water permeability, and which does not allow protein adsorption and useful protein loss. However, studies on hemoconcentration membranes have not been conducted yet. The purpose of this study was to analyze three-dimensional pore structures and protein fouling before and after blood contact with capillary membranes using the tortuous pore diffusion model and a scanning probe microscope system. We examined two commercially available capillary membranes of similar polymer composition that are successfully used in hemoconcentration clinically. Assuming the conditions of actual use in cardiopulmonary bypass, we perfused these membranes with bovine blood. Pure water permeability before and after bovine blood perfusion was measured using the dead-end filtration. The scanning probe microscopy system was used for analysis. High-resolution three-dimensional pore structures on the inner surface of the membranes were observed before blood contact. On the other hand, pore structures after blood contact could not be observed due to protein fouling. The pore diameters calculated by the tortuous pore diffusion model and scanning probe microscopy were mostly similar and could be validated reciprocally. Achievable pure water permeabilities showed no difference despite protein fouling, leading to low values of albumin SC. This is due to the mechanism that protein fouling occurs on the membrane surface, while there is little internal pore blocking. Therefore, controlling the fouling is essential for membranes in medical use. These characteristics of the hemoconcentration membranes examined in this study are suitable for clinical use.

Download Full-text

K-3 Scanning electron microscopy and scanning probe microscopy for visualizing the three-dimensional structure of cells and tissues

Microscopy ◽

10.1093/jmicro/dfz041 ◽

2019 ◽

Vol 68 (Supplement_1) ◽

pp. i21-i21

Author(s):

Tatsuo Ushiki

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Scanning Probe Microscopy ◽

Three Dimensional ◽

Scanning Probe ◽

Dimensional Structure ◽

Probe Microscopy ◽

Three Dimensional Structure ◽

Scanning Electron

Download Full-text

Determination and Correction of Position Detection Nonlinearity in Single Particle Tracking and Three-Dimensional Scanning Probe Microscopy

Microscopy and Microanalysis ◽

10.1017/s1431927604040140 ◽

2004 ◽

Vol 10 (4) ◽

pp. 425-434 ◽

Cited By ~ 14

Author(s):

Christian Tischer ◽

Arnd Pralle ◽

Ernst-Ludwig Florin

Keyword(s):

Optical Tweezers ◽

Particle Tracking ◽

Single Particle ◽

Scanning Probe Microscopy ◽

Three Dimensional ◽

Single Particle Tracking ◽

Scanning Probe ◽

Detection Scheme ◽

Probe Microscopy ◽

Position Detection

A general method is presented for determining and correcting nonlinear position detector responses in single particle tracking as used in three-dimensional scanning probe microscopy based on optical tweezers. The method uses locally calculated mean square displacements of a Brownian particle to detect spatial changes in the sensitivity of the detector. The method is applied to an optical tweezers setup, where the position fluctuations of a microsphere within the optical trap are measured by an interferometric detection scheme with nanometer precision and microsecond temporal resolution. Detector sensitivity profiles were measured at arbitrary positions in solution with a resolution of approximately 6 nm and 20 nm in the lateral and axial directions, respectively. Local detector sensitivities are used to reconstruct the real positions of the particle from the measured position signals.

Download Full-text