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Solvent‐free liquid avidin as a step towards cold chain elimination

DOI: 10.1002/bit.27587 DOI Help

Authors: Liem Bui-le (Imperial College London) , Alex P. S. Brogan (King's College London) , Jason P. Hallett (Imperial College London; King's College London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biotechnology And Bioengineering

State: Published (Approved)
Published: October 2020
Diamond Proposal Number(s): 22514 , 19247

Abstract: The temperature sensitivity of vaccines and therapeutic proteins forces the distribution of life‐saving treatments to rely heavily on the temperature‐controlled (usually 2 – 8 °C) supply and distribution network known as the cold chain. Here, using avidin as a model, we demonstrate how surface engineering could significantly increase the thermal stability of therapeutic proteins. A combination of spectroscopic (Fourier Transform Infrared, circular dichroism and ultraviolet‐visible) and scattering techniques (dynamic light scattering, small‐angle and wide‐angle X‐ray scattering) were deployed to probe the activity, structure, and stability of the model protein. Temperature‐dependent synchrotron radiation circular dichroism spectroscopy was used to demonstrate a significant increase in thermal stability, with a half denaturation temperature of 139.0 °C and reversible unfolding with modified avidin returning to a 90 % folded state when heated to temperatures below 100 °C. Accelerated ageing studies revealed that modified avidin retained its secondary structure after storage at 40 °C for 56 days, equivalent to 160 days at 25 °C. Furthermore, binding studies with multiple ligands revealed that the binding site remained functional after modification. As a result, this approach has potential as a storage technology for therapeutic proteins and the elimination of the cold chain, enabling dissemination of life‐saving vaccines worldwide.

Journal Keywords: cold‐chain; solvent‐free biofluid; surface engineering; thermal stability; vaccine storage

Subject Areas: Biology and Bio-materials, Medicine

Instruments: B21-High Throughput SAXS , B23-Circular Dichroism , I22-Small angle scattering & Diffraction