Fradique, R. | Search bioRxiv

bioRxiv2023

Surface crosslinking of virus-like particles increases resistance to proteases, low pH and mechanical stress for mucosal applications

AbstractVirus-like particles (VLPs) are emerging as nano-scaffolds in a variety of biomedical applications including the delivery of vaccine antigens to mucosal surfaces. These soft, colloidal, and proteinaceous structures (capsids) are nevertheless susceptible to mucosal environmental factors which limit their usefulness. We addressed this issue by crosslinking multiple capsid surface reactive residues using polyethylene glycol tethers. Surface crosslinking enhanced the colloidal stability and mechanical strength of VLPs against low pH, proteases, and mechanical agitation, while it did not interfere with function as vaccine. Chemical crosslinking thus offers a viable means to enhance the resilience of VLPs in mucosal applications.

biophysics↗

bioRxiv2023

Assessing motile cilia coverage and beat frequency in mammalian in-vitro cell culture tissues

Cilia density, distribution and beating frequency are important parameters lung tissues, for example in diagnostics of Primary Ciliary Dyskinesia, and in the study of in vitro models, e.g. derived from induced Pluripotent Stem Cells. Video microscopy can be used to characterise these parameters, but most tools available at the moment are limited in the type of information they can provide, usually only describing the ciliary beat frequency of very small areas, while requiring human intervention and training for their use. We propose a novel and open source method to fully characterise cilia beating frequency and motile cilia coverage in an automated fashion without user intervention. We demonstrate the ability to differentiate between different coverage densities, identifying even small patches of cilia in a larger field of view, and to fully characterise the cilia beating frequency of all moving areas. We also show that the method can be used to combine multiple fields of view to better describe a sample without relying on small pre-selected regions of interest. This is released with a simple graphical user interface for file handling, enabling a full analysis of individual fields of view in a few minutes on a typical personal computer.

biophysics↗