Tailoring polyvinyl alcohol-sodium alginate (PVA-SA) hydrogel beads by controlling crosslinking pH and time

Pieter Candry*, Bruce J. Godfrey, Ziwei Wang, Fabrizio Sabba, Evan Dieppa, Julia Fudge, Oluwaseyi Balogun, George Wells, Mari Karoliina Henriikka Winkler

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Hydrogel-encapsulated catalysts are an attractive tool for low-cost intensification of (bio)-processes. Polyvinyl alcohol-sodium alginate hydrogels crosslinked with boric acid and post-cured with sulfate (PVA-SA-BS) have been applied in bioproduction and water treatment processes, but the low pH required for crosslinking may negatively affect biocatalyst functionality. Here, we investigate how crosslinking pH (3, 4, and 5) and time (1, 2, and 8 h) affect the physicochemical, elastic, and process properties of PVA-SA-BS beads. Overall, bead properties were most affected by crosslinking pH. Beads produced at pH 3 and 4 were smaller and contained larger internal cavities, while optical coherence tomography suggested polymer cross-linking density was higher. Optical coherence elastography revealed PVA-SA-BS beads produced at pH 3 and 4 were stiffer than pH 5 beads. Dextran Blue release showed that pH 3-produced beads enabled higher diffusion rates and were more porous. Last, over a 28-day incubation, pH 3 and 4 beads lost more microspheres (as cell proxies) than beads produced at pH 5, while the latter released more polymer material. Overall, this study provides a path forward to tailor PVA-SA-BS hydrogel bead properties towards a broad range of applications, such as chemical, enzymatic, and microbially catalyzed (bio)-processes.

Original languageEnglish (US)
Article number20822
JournalScientific reports
Volume12
Issue number1
DOIs
StatePublished - Dec 2022

Funding

P.C. acknowledges the support provided by U.S. Department of Energy, Office of Science, Office of Biological & Environmental Research (#DE-SC0020356). J.F. was supported by the National Institutes of Health (1R01DK130815-01). O.B and G.W. acknowledge final support from the National Science Foundation under the grant numbers, CBET 1937290 and CMMI 2100447. The authors would also like to acknowledge Buddy Ratner for useful discussions, and Bowen Xie for assistance with sample analysis.

ASJC Scopus subject areas

  • General

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