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The Effect of Swelling Ratio on the Coulter Underestimation of Hydrogel Microsphere Diameters.

Pellegrini M, Cherukupalli A, Medini M, Falkowski R, Olabisi R - Tissue Eng Part C Methods (2015)

Bottom Line: This phenomenon has also been observed in hydrogel particles, but not characterized.Since the Coulter principle uses the displacement of electrolyte to determine particle size, electrolyte contained within the swelled hydrogel microparticles results in an underestimate of actual particle diameters.The increased use of hydrogel microspheres in biomedical applications has led to the increased application of the Coulter principle to evaluate the size distribution of microparticles.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Rutgers University , Piscataway, New Jersey.

ABSTRACT
It has been demonstrated that the diameters of porous particles are underestimated by Coulter measurements. This phenomenon has also been observed in hydrogel particles, but not characterized. Since the Coulter principle uses the displacement of electrolyte to determine particle size, electrolyte contained within the swelled hydrogel microparticles results in an underestimate of actual particle diameters. The increased use of hydrogel microspheres in biomedical applications has led to the increased application of the Coulter principle to evaluate the size distribution of microparticles. A relationship between the swelling ratio of the particles and their reported Coulter diameters will permit calculation of the actual diameters of these particles. Using polyethylene glycol diacrylate hydrogel microspheres, we determined a correction factor that relates the polymer swelling ratio and the reported Coulter diameters to their actual size.

No MeSH data available.


Related in: MedlinePlus

Correction factor, f, plotted against hydrogel physical properties. Trendlines were fit only to PEGDA data, then alginate was plotted on the same graph to evaluate whether fit equations would predict alginate physical properties. (a) PEGDA hydrogel swelling ratios versus correction factor. Linear trendline equation closely predicts alginate values. (b) PEGDA hydrogel molecular weights versus correction factor. Linear trendline shows no relation to alginate molecular weights. (c) PEGDA hydrogel mesh size versus correction factor. Quadratic trendline shows no relation to alginate molecular weights.
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f2: Correction factor, f, plotted against hydrogel physical properties. Trendlines were fit only to PEGDA data, then alginate was plotted on the same graph to evaluate whether fit equations would predict alginate physical properties. (a) PEGDA hydrogel swelling ratios versus correction factor. Linear trendline equation closely predicts alginate values. (b) PEGDA hydrogel molecular weights versus correction factor. Linear trendline shows no relation to alginate molecular weights. (c) PEGDA hydrogel mesh size versus correction factor. Quadratic trendline shows no relation to alginate molecular weights.

Mentions: Diameters measured by the Coulter counter were consistently smaller than those determined by imaging for every molecular weight PEGDA (Fig. 1a–c). Once a correction factor (f) had been determined numerically (Table 1), Coulter distributions were multiplied by f and overlaid with ImageJ distributions (Fig. 1d–f). Values for hydrogel swelling ratio, molecular weight, and mesh size were calculated to determine whether there was any correlation with f (Table 1). For PEG hydrogels, the correction factor f was quadratically related to hydrogel mesh size and linearly related to hydrogel molecular weight and swelling ratio. Alginate was used as a test material to evaluate whether the fits of f could be used to predict values for f in materials other than PEGDA. There was a correlation to the swelling ratio, but not to molecular weight or mesh size (Fig. 2), which predicted an f of 0.144 compared to the actual numerically determined value of 0.125. The empirical equation that relates the correction factor to the swelling ratio is as follows:\documentclass{aastex}\usepackage{amsbsy}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{bm}\usepackage{mathrsfs}\usepackage{pifont}\usepackage{stmaryrd}\usepackage{textcomp}\usepackage{portland, xspace}\usepackage{amsmath, amsxtra}\pagestyle{empty}\DeclareMathSizes{10}{9}{7}{6}\begin{document}\begin{align*}f = - 0.0485S + 1.2355 \tag{4}\end{align*}\end{document}


The Effect of Swelling Ratio on the Coulter Underestimation of Hydrogel Microsphere Diameters.

Pellegrini M, Cherukupalli A, Medini M, Falkowski R, Olabisi R - Tissue Eng Part C Methods (2015)

Correction factor, f, plotted against hydrogel physical properties. Trendlines were fit only to PEGDA data, then alginate was plotted on the same graph to evaluate whether fit equations would predict alginate physical properties. (a) PEGDA hydrogel swelling ratios versus correction factor. Linear trendline equation closely predicts alginate values. (b) PEGDA hydrogel molecular weights versus correction factor. Linear trendline shows no relation to alginate molecular weights. (c) PEGDA hydrogel mesh size versus correction factor. Quadratic trendline shows no relation to alginate molecular weights.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4663640&req=5

f2: Correction factor, f, plotted against hydrogel physical properties. Trendlines were fit only to PEGDA data, then alginate was plotted on the same graph to evaluate whether fit equations would predict alginate physical properties. (a) PEGDA hydrogel swelling ratios versus correction factor. Linear trendline equation closely predicts alginate values. (b) PEGDA hydrogel molecular weights versus correction factor. Linear trendline shows no relation to alginate molecular weights. (c) PEGDA hydrogel mesh size versus correction factor. Quadratic trendline shows no relation to alginate molecular weights.
Mentions: Diameters measured by the Coulter counter were consistently smaller than those determined by imaging for every molecular weight PEGDA (Fig. 1a–c). Once a correction factor (f) had been determined numerically (Table 1), Coulter distributions were multiplied by f and overlaid with ImageJ distributions (Fig. 1d–f). Values for hydrogel swelling ratio, molecular weight, and mesh size were calculated to determine whether there was any correlation with f (Table 1). For PEG hydrogels, the correction factor f was quadratically related to hydrogel mesh size and linearly related to hydrogel molecular weight and swelling ratio. Alginate was used as a test material to evaluate whether the fits of f could be used to predict values for f in materials other than PEGDA. There was a correlation to the swelling ratio, but not to molecular weight or mesh size (Fig. 2), which predicted an f of 0.144 compared to the actual numerically determined value of 0.125. The empirical equation that relates the correction factor to the swelling ratio is as follows:\documentclass{aastex}\usepackage{amsbsy}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{bm}\usepackage{mathrsfs}\usepackage{pifont}\usepackage{stmaryrd}\usepackage{textcomp}\usepackage{portland, xspace}\usepackage{amsmath, amsxtra}\pagestyle{empty}\DeclareMathSizes{10}{9}{7}{6}\begin{document}\begin{align*}f = - 0.0485S + 1.2355 \tag{4}\end{align*}\end{document}

Bottom Line: This phenomenon has also been observed in hydrogel particles, but not characterized.Since the Coulter principle uses the displacement of electrolyte to determine particle size, electrolyte contained within the swelled hydrogel microparticles results in an underestimate of actual particle diameters.The increased use of hydrogel microspheres in biomedical applications has led to the increased application of the Coulter principle to evaluate the size distribution of microparticles.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Rutgers University , Piscataway, New Jersey.

ABSTRACT
It has been demonstrated that the diameters of porous particles are underestimated by Coulter measurements. This phenomenon has also been observed in hydrogel particles, but not characterized. Since the Coulter principle uses the displacement of electrolyte to determine particle size, electrolyte contained within the swelled hydrogel microparticles results in an underestimate of actual particle diameters. The increased use of hydrogel microspheres in biomedical applications has led to the increased application of the Coulter principle to evaluate the size distribution of microparticles. A relationship between the swelling ratio of the particles and their reported Coulter diameters will permit calculation of the actual diameters of these particles. Using polyethylene glycol diacrylate hydrogel microspheres, we determined a correction factor that relates the polymer swelling ratio and the reported Coulter diameters to their actual size.

No MeSH data available.


Related in: MedlinePlus