[Soft Matter Café] Enzyme encapsulation in lipid sponge phase nanoparticles and the interactions at the lipid aqueous interface
Non-lamellar lipid aqueous phases, such as reverse cubic or hexagonal phases, have increasingly been used to entrap biomolecules. We here discuss encapsulation of two key types of enzymes of different sizes, namely Aspartic protease (34 KDa) and Beta-galactosidase (460 KDa) [1,2]. Although the curvature of the lipid aqueous interfaces in these phases determines the size of the aqueous cavities and hence the space given to the enzyme, the interaction between the enzyme and the lipid layer is an important factor that controls the efficiency of the encapsulation. We used mixtures of acylglycerides and acyldiglycerides, which are able to form highly swollen sponge phases (L3), with aqueous pores up to 13 nm of diameter . This system can with the help of the dispersing agent polysorbate 80 (P80) form well defined nanoparticles in excess water with an internal L3 structure . These particles adsorb at the interface to form a lipid bilayer as shown by QCM-D and neutron reflectometry . Raman spectroscopy results for the sponge phases show large similarities in lipid chain confirmation and head group interactions as in the lamellar and reverse bicontinuous cubic phase in the same lipid system as all three structures are formed by lipid bilayers . Size exclusion chromatography show efficient encapsulation of both enzymes, yet they retained their enzymatic activity over months, surpassing the storage stability of pure enzymes in solution [1,2]. The reason for this can be understood in terms penetration of the enzymes into the formed lipid bilayer as shown by Raman spectroscopy  and neutron reflectometry . This has been confirmed by neutron spin echo and molecular dynamics simulations .
 M. Valldeperas, M. Talaikis, S. K. Dhayal, M. Velicka, J. Barauskas, G. Niaura, T. Nylander. Biophys. J. 2019, 117, 829-843;  J. Gilbert, M. Valldeperas, S. K. Dhayal, J. Barauskas, C. Dicko, T. Nylander. Nanoscale 2019, 11, 21291–21301;  M. Valldeperas, M. Wisniewska, M. Ram-On, E. Kesselman, D. Danino, T. Nylander and J. Barauskas, Langmuir 32 (2016) 8650;  M. Valldeperas, A. P. Dabkowska, G. K. Pálsson, S. Rogers, N. Mahmoudi, A. Carnerup, J. Barauskas and T. Nylander, Soft Matter 15 (2019) 2178;  M. Talaikis, M. Valldeperas, I. Matulaitienė, J. Latynis Borzova, J. Barauskas, G. Niaura and T. Nylander, J. Phys. Chem. B 123 (2019) 2662;  M. Valldeperas, Lipid sponge phase nanostructures as carriers for enzymes. Doctoral Thesis, Lund University, Lund, Sweden (2019);  J. Gilbert, I. Ermilova, M. Nagao, J. Swenson, T. Nylander. Nanoscale, 2022, 14, 6990–7002
About the speaker: Prof. Tommy Nylander specialized in Food Technology at LU as an undergraduate before completing his PhD there in chemical engineering and biophysical technology. He completed his PhD in the same topic at Lund University under the supervision of Prof. Kåre Larsson in 1987. In 1990 he did a postdoc at Australian National University, Department of Applied Mathematics, Canberra, Australia with Prof. Barry Ninham. In 2000 he was appointed senior lecturer at the Div. of Physical Chemistry, LU and in 2007 he was promoted to full professor at the same division. The main theme of Prof. Nylander scientific activity has been to relate interfacial behaviour of surface-active molecules of biological origin to their solution behaviour, many of them focus on food related scientific challenges. He has published 270 scientific articles and book chapters within this area. He has extensive international collaboration both with academia and industry. Tommy Nylander was a member of the first Scientific Advisory Committee for ESS (2008-2011).