Segregation Behavior of Polysaccharide–Polysaccharide Mixtures—A Feasibility Study

Abstract

The segregative phase separation behavior of biopolymer mixtures composed entirely of polysaccharides was investigated. First, the electrical, optical, and rheological properties of alginate, modified beet pectin, and unmodified beet pectin solutions were characterized to determine their electrical charge, molecular weight, solubility, and flow behavior. Second, suitable conditions for inducing phase segregation in biopolymer mixtures were established by measuring biopolymer concentrations and segregation times. Third, alginate–beet pectin mixtures were blended at pH 7 to promote segregation and the partitioning of the biopolymers between the upper and lower phases was determined using UV–visible spectrophotometry, colorimetry, and calcium sensitivity measurements. The results revealed that phase separation depended on the overall biopolymer concentration and the degree of biopolymer hydrophobicity. A two-phase system could be formed when modified beet pectins (DE 68%) were used but not when unmodified ones (DE 53%) were used. Our measurements demonstrated that the phase separated systems consisted of a pectin-rich lower phase and an alginate-rich upper phase. These results suggest that novel structures may be formed by utilization of polysaccharide–polysaccharide phase separation. By controlling the product formulation and processing conditions it may therefore be possible to fabricate biopolymer particles with specific dimensions, shapes, and internal structures.

Aqueous Two‐Phase Enabled Low Viscosity 3D (LoV3D) Bioprinting of Living Matter

“…While the ability to form a stable ATPS is crucial for LoV3D bioprinting, this does not constrain its applicability as most commonly utilized (bio)polymers in tissue engineering are able to form ATPS. [19][20][21] To confirm the universal applicability of our approach, the formation of a stable interface was investigated for several commonly used (bio)polymer systems including dextran, PEG, alginic acid, gelatin, and heparin. Here, several combinations of polymers resulted in a stable interface (Figure 1c and Figure S2, Supporting Information) and thus were considered suitable for ATPS printing applications.…”