Acoustic method for permeability measurement of tissue-engineering scaffold

Abstract

An accurate intrinsic permeability measurement system has been designed and realized in order to quantify the inter-pore connectivity structure of tissue-engineering scaffolds by using a single (pressure) transducer. The proposed method uses a slow alternating airflow as a fluid medium and allows at the same time a simple and accurate measurement procedure. The intrinsic permeability is determined in the linear Darcy's region, and deviation from linearity due to inertial losses is also quantified. The structural parameters of a scaffold, such as effective porosity, tortuosity and effective length of cylindrical pores, are estimated using the classical Ergun's equation recently modified by Wu et al. From this relation, it is possible to achieve a well-defined range of data and associated uncertainties for characterizing the structure/architecture of tissue-engineering scaffolds. This quantitative analysis is of paramount importance in tissue engineering, where scaffold topological features are strongly related to their biological performance.

Digital light processing stereolithography of hydroxyapatite scaffolds with bone‐like architecture, permeability, and mechanical properties

“…23 Impregnation of alumina matrix in eight-harness satin Nextel 610 fabric has been studied numerically in Ref. [ 24 ]. Modeling approaches used in the above work generally involved modeling the flow of a high viscosity resin through porous media and modeling the chemical reactions and volumetric changes during processing.…”

“…In this work, the intrinsic Darcian permeability k was experimentally determined by measuring the pressure wave drop of a slow alternating airflow, [24][25][26] with a known volumetric airflow rate through the scaffold, according to Equation 2: where q v,rms was the root-mean-square (r.m.s.) value of alternating volumetric airflow rate, that is,…”

“…The amplitude of the sinusoidal pressure component was measured by a proper capacitive microphone, with a given sensitivity in mV/Pa; the measurement device and the experimental procedure were previously described in detail elsewhere. 24 Therefore, by combining the quantities above described, the experimental intrinsic Darcian permeability k was obtained by the following physical model (Equation ( 3)):…”

“…According to Darcy's law, 24,26,27 a very low frequency of oscillation (ω ≈ 1 rad/s) was imposed to keep the laminar regime of the volumetric airflow rate. Once the quantities in Equation ( 3) have been assessed, the intrinsic Darcian permeability k of the scaffolds was determined from experimental measurements performed on six different samples (diameter 4.99 ± 0.13 mm, height 9.88 ± 0.09 mm).…”

A novel vertical greenery module system for building envelopes: The results and outcomes of a multidisciplinary research project

“…The hydraulic conductivity, K, a parameter that describes the behaviour of a given fluid as it passes through the interstitial spaces of a porous material, was determined on the same materials on the basis of the measurement of intrinsic permeability k, using an appropriate measuring procedure [38], in both loaded and unloaded conditions [39].…”