title: Labelling Bacterial Nanocages with Photo-switchable Fluorophores.
abstract: The robustness and biocompatibility of bacterial nanocages holds promise for bio-nanotechnologies. The propensity of these nano-carriers to penetrate cells has been demonstrated, which calls for the development of tracking strategies, both in vitro and in vivo. Here, we label bacterial nanocages with photo-switchable fluorophores, to facilitate their imaging by super-resolution microscopy. We demonstrate the functionalization of the encapsulin from Brevibacterium linens with a spiropyran, which is not fluorescent, by covalent attachment to the amine residues at the outer encapsulin shell. Upon alternating irradiation with ultraviolet and visible light, the spiropyran switches forth and back to its fluorescent merocyanine photo-isomer and thus the fluorescence can be switched on and off, reversibly. We also show that the bacterial compartments preserve their structural integrity upon covalent modification and over at least five irradiation cycles.
authors: Bio-inspired and Smart Materials, Laboratory for Biomolecular Nanotechnology (BNT), MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands.
authors: Rindia M
authors: RM
authors: Putri
authors: Bio-inspired and Smart Materials, Laboratory for Biomolecular Nanotechnology (BNT), MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands.
authors: Jean Wilfried
authors: JW
authors: Fredy
authors: Bio-inspired and Smart Materials, Laboratory for Biomolecular Nanotechnology (BNT), MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands.
authors: Jeroen J L M
authors: JJ
authors: Cornelissen
authors: Bio-inspired and Smart Materials, Laboratory for Biomolecular Nanotechnology (BNT), MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands.
authors: Melissa S T
authors: MS
authors: Koay
authors: Bio-inspired and Smart Materials, Laboratory for Biomolecular Nanotechnology (BNT), MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands. n.h.katsonis@utwente.nl.
authors: Nathalie
authors: N
authors: Katsonis
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D001578:Benzopyrans / Q000737:chemistry*; D001951:Brevibacterium / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D008027:Light; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D010316:Particle Size; D055668:Photochemical Processes; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D001578:Benzopyrans; D005456:Fluorescent Dyes; D007211:Indoles; C548873:merocyanine
keywords: molecular switches; photochromism; protein cages; self-assembly; spiropyrans