Lipid nanoparticles (LNPs) are emerging as important carriers for mRNA delivery in RNA therapeutics, but key barriers must still be overcome before this strategy can achieve broad clinical impact beyond vaccines. In this presentation, I will describe our recent efforts to address some of these challenges by integrating micro- and nanofluidic systems with surface-sensitive optical microscopy. The work centers on the visualization and analysis of individual biological nanoparticles, including extracellular vesicles (EVs) and mRNA-containing LNPs. One approach combines label-free scattering with fluorescence imaging, enabling high-resolution single-particle characterization [1]. In parallel, our studies of LNP interactions with endosomal membrane mimics [2] have been extended by forming these mimics on nonporous silica rather than on planar glass substrates. This platform enables measurements of pH-dependent LNP fusion with supported endosomal membrane mimics and yields results that correlate well with in vitro data on endosomal escape efficiency and protein expression. [3] Using these systems, we have further quantified the refractive index and size of individual LNPs and, through selective fluorescence labeling, established direct correlations between these parameters and both cargo loading and surface-marker composition. [4] These studies have also provided insight into the contribution of protein-corona formation to the maturation processes that govern cellular uptake and mRNA delivery [5]. Collectively, these investigations advance our understanding of nanoparticle heterogeneity and its consequences for cellular membrane interactions, including the mechanisms underlying endosomal escape, and thereby support the development of next-generation nanocarriers with improved performance for oligonucleotide delivery. 

References

[1] Parkkila, P. et al., ” Time-resolved surface-sensitive waveguide scattering microscopy of single extracellular vesicles reveals content and biomarker heterogeneity” researchsquare 2024 https://doi.org/10.21203/rs.3.rs-4713578/v1
[2] Aliakbarinodehi, N. et al., “Interaction Kinetics of Individual mRNA-Containing Lipid Nanoparticles with an Endosomal Membrane Mimic: Dependence on pH, Protein Corona Formation, and Lipoprotein Depletion” ACS Nano 2022, 16 (12), 20163-20173.
[3] Aliakbarinodehi, N. et al., “Time-Resolved Inspection of Ionizable Lipid-Facilitated Lipid Nanoparticle Disintegration and Cargo Release at an Early Endosomal Membrane Mimic” ACS Nano 2024, 18 (34), 22989-23000.
[4] Sjoberg, M. et al., “Multiparametric functional characterization of individual lipid nanoparticles using surface-sensitive light-scattering microscopy” PNAS 2025, 122 (21), e2426601122.
[5] Niederkofler, S. et al. 2025. "Effects of Serum Incubation on Lipid Nanoparticle PEG Shedding, mRNA Retention, and Membrane Interactions." ACS Applied Materials & Interfaces 17(47): 64219-64231.

BIO
Fredrik Höök is Professor of Nanobio Physics at Chalmers University of Technology, where he has built an internationally recognised research environment at the interface of surface science, biophysics, and bioanalytical technology. His work has been driven by a long-standing ambition to develop quantitative methods that reveal how biological molecules and nanoparticles interact with surfaces and membrane-like environments, with applications ranging from fundamental biointerface science to medical diagnostics, drug delivery, and regenerative medicine.

A major part of Höök’s scientific impact lies in method development. His group contributed decisively to the maturation of quartz crystal microbalance technology into a widely used bioanalytical tool, helping establish it as an important instrument in biologically oriented surface science. The group has also made pioneering contributions to nanoplasmonics for biosensing, including the development of material-specific surface chemistries that improve sensitivity, quantification, and analytical robustness. Another contribution is the introduction of TIRF-based equilibrium fluctuation analysis, a single-molecule approach that has been adapted to probe dynamic interactions between viruses, nanoparticles, and cell-membrane mimics with exceptionally high sensitivity. This work has provided new possibilities for determining association and dissociation kinetics of low-molecular-weight compounds binding to membrane receptors and has also attracted interest from the pharmaceutical industry.

The research environment Höök has developed is characterised by close integration of engineering, physical chemistry, and life science, and by extensive collaboration across academic and industrial boundaries. His current work focuses on complementary surface-sensitive microscopy and analytical approaches, including combinations of fluorescence, scattering, and holographic microscopy, to characterise biological nanoparticles such as viruses, extracellular vesicles, and targeted drug-delivery systems at the single-particle level. These efforts are supported by theory, modelling, and advanced image analysis, and are aimed both at understanding biomolecular mechanisms and at guiding the design of functional nanomaterials and oligonucleotide delivery vehicles.

This interdisciplinary profile has also shaped Höök’s role as a scientific leader. He directed the Vinnova-funded Innovations for Future Health programme, a strategic collaboration between Chalmers, the University of Gothenburg, Karolinska Institutet, and AstraZeneca from 2009 to 2016. Building on this foundation, he has since 2017 led the large SSF-funded industrial research centre FoRmulaEx, dedicated to molecular design and analysis for next-generation pharmaceuticals. In the Swedish Research Council’s 2023 national evaluation of physics research, FoRmulaEx was highlighted as a particularly successful example of how fundamental research in an academic setting can generate broad societal impact. In 2024, Höök also helped initiate the Chalmers Precision HealthTech Hub, supported by Region Västra Götaland, with the aim of creating an open infrastructure for formulation, characterisation, and functional evaluation of biological nanoparticles and nucleic acid delivery systems.

His work has also contributed to innovation and knowledge transfer through extensive national and international collaborations, mobility of young researchers, and company formation, including the recent spinouts Nanolyze and InSingulo, focused on biological nanoparticle characterisation and drug screening. Across these activities, Höök has combined fundamental curiosity-driven science with a strong commitment to creating methods, environments, and partnerships that can accelerate both discovery and practical application. He is a member of the Royal Swedish Academy of Engineering Sciences (IVA) and the Royal Swedish Academy of Sciences (KVA).