Transport of biological molecules in surfactant–alginate composite hydrogels

Abstract

Obstructed transport of biological molecules can result in improper release of pharmaceuticals or biologics from biomedical devices. Recent studies have shown that nonionic surfactants, such as Pluronic® F68 (F68), positively alter biomaterial properties, such as mesh size and microcapsule diameter. To further understand the effect of F68 (incorporated at concentrations well above the critical micelle concentration (CMC)) in traditional biomaterials, the transport properties of BSA and riboflavin were investigated in F68-alginate composite hydrogels. Results indicate that small molecule transport (represented by riboflavin) was not significantly hindered by F68 in homogeneously crosslinked hydrogels (up to an 11% decrease in loading capacity and 14% increase in effective diffusion coefficient, Deff), while protein transport in homogeneously crosslinked hydrogels (represented by BSA) was significantly affected (up to a 43% decrease in loading capacity and 40% increase in Deff). For inhomogeneously crosslinked hydrogels (CaCl2 or BaCl2 gelation), the Deff increased up to 50% and 83% for small molecule and proteins, respectively. Variation in the alginate gelation method was shown to affect transport through measurable changes in swelling ratio (30% decrease) and observable changes in crosslinking structure as well as up to a 3.6 and 11.8-fold difference in Deff for riboflavin and BSA, respectively. The change in protein transport properties is a product of mesh size restrictions (10–25 nm estimated by mechanical properties) and BSA-F68 interaction (DLS). Taken as a whole, these results show that incorporation of a nonionic surfactant at concentrations above the CMC can affect device functionality by impeding the transport of large biological molecules.

Addition of perfluorocarbons to alginate hydrogels significantly impacts molecular transport and fracture stress

“…However, the solutions containing PFOB were also statistically similar to 1% alginate with 1% or 2% F68, indicating that the change in the viscosity is mainly due to surfactant addition. 18 This is in agreement with our previous work on alginate/F68 solutions. 18 Increasing trends in viscosity should be monitored further for greater PFC incorporation or use of a PFC with higher molecular weight (>10%) since we expect significant increases in the viscosity to affect processing parameters in biomedical applications.…”

“…18,20 Briefly, CaEDTA was added to an alginate or alginate/F68/PFOB solution at a final concentration of 50 mM CaEDTA. Glucono-δ-lactone (GDL) was added initiate calcium release (50 mM).…”

“…The final alginate concentration for all solution formulations in this study is 1% w/v, though swelling studies indicate that during gelation more water is lost from formulations containing F68. 18 …”

“…The D eff was determined using experimental data and a 3D diffusion model 19,22,23 shown in Equation 1, as previously described. 18 Briefly, the mass of solute released while maintaining sink conditions throughout the 120 minute time course was quantified and fit to the model. $$M_t^{*}=\frac{M_t}{M_{\infty }}=1-true(\frac{8}{h^2{r}^2}{\sum }_{j=1}^{\infty }{\alpha }_j^{-2}{e}^{-D_{\mathit{\text{eff}}}{\alpha }_j^{2}t}true)true({\sum }_{k=0}^{\infty }{\beta }_k^{-2}{e}^{-D_{\mathit{\text{eff}}}{\beta }_k^{2}t}true)$$…”

Synthesis of environment friendly nonionic surfactants from sugar base and characterization of interfacial properties for detergent application

“…Nonionic surfactants generally exhibit a very low toxicity level and are also used as cleaners, wetting agents and emulsifiers in pharmaceuticals, cosmetics and food products. One of the major issues in surfactant and detergent industry is growing environmental concern such as biodegradability and mildness of surfactant, pollution control in manufacturing processes, and consumer desire for effective and eco-friendly green products [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”