Heterogeneity in desiccated solutions: Implications for biostabilization

Vishard Ragoonanan, Alptekin Aksan

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Biopreservation processes such as freezing and drying inherently introduce heterogeneity. We focused on exploring the mechanisms responsible for heterogeneity in isothermal, diffusively dried biopreservation solutions that contain a model protein. The biopreservation solutions used contained trehalose (a sugar known for its stabilization effect) and salts (LiCl, NaCl, MgCl 2, and CaCl2). Performing Fourier transform infrared spectroscopy analysis on the desiccated droplets, spatial distributions of the components within the dried droplet, as well as their specific interactions, were investigated. It was established that the formation of multiple thermodynamic states was induced by the spatial variations in the cosolute concentration gradients, directly affecting the final structure of the preserved protein. The spatial distribution gradients were formed by two competing flows that formed within the drying droplet: a dominant peripheral flow, induced by contact line pinning, and the Marangoni flow, induced by surface tension gradients. It was found that the changes in cosolute concentrations and drying conditions affected the spatial heterogeneity and stability of the product. It was also found that trehalose and salts had a synergistic stabilizing effect on the protein structure, which originated from destructuring of the vicinal water, which in turn mediated the interactions of trehalose with the protein. This interaction was observed by the change in the glycosidic CO, and the CH stretch vibrations of the trehalose molecule.

Original languageEnglish (US)
Pages (from-to)2212-2227
Number of pages16
JournalBiophysical journal
Issue number6
StatePublished - Mar 15 2008

Bibliographical note

Funding Information:
This research is supported by a grant (GIA-20328) from the Office of the Dean of the Graduate School of the University of Minnesota.


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