Journal Article

Hierarchical Functionalisation of UiO-66(Zr)-NH2 with Cysteine, PEG, and SARS-CoV-2 Spike RBD to Facilitate ACE2 Receptor Targeting in Model Cells

Zelenková, Gabriela, Migasová, Alexandra, Zakany, Florina, Bodnár, Andrea, Schubert, Tim, Almáši, Miroslav, Salaková, Michaela, Szűcs, Péter, Zelenka, Tomáš, Váradi, Judit, Huntošová, Veronika, Walter, Andreas, Chowdhury, Arpan, Vámosi, György, Bilakovics, Noémi, Benziane, Anass, Sedlák, Erik, Jurašeková, Zuzana, Baddour, Saraa, Ambro, Ľuboš, Kovacs, Tamas

2026

Overview

Hierarchical functionalisation of the UiO-66(Zr)-NH2 metal–organic framework with cysteine, poly(ethylene glycol) (PEG), and the SARS-CoV-2 spike receptor-binding domain (RBD) was developed to enable receptor-specific interaction with the angiotensin-converting enzyme 2 receptor (ACE2) in model cells. Post-synthetic modification using cysteine and heterobifunctional PEG linkers allowed controlled bioconjugation of SpyTag-labelled RBD via SpyTag/SpyCatcher chemistry, while preserving the crystallinity, microporosity, and intrinsic optical properties of the UiO-66(Zr)-NH2 framework. Comprehensive physicochemical characterisation confirmed successful surface functionalisation, tunable aggregation behaviour, and retention of multimodal optical characteristics. Cellular studies in HEK293T and HeLa cells overexpressing EGFP-tagged ACE2 demonstrated enhanced and selective association and uptake of RBD-functionalised nanoparticles compared with non-targeted analogues. Multimodal fluorescence imaging, fluorescence lifetime imaging microscopy, flow-cytometry, and electron microscopy indicated ACE2-dependent endocytic internalisation, with predominant localisation in endosomal and autophagosomal compartments, while both amine- and cysteine-modified formulations exhibited good biocompatibility. Overall, this study establishes a virus-mimetic, ACE2-targeted UiO-66(Zr)-based nanosystem as a proof-of-concept biointerface platform for receptor-specific cellular delivery and imaging, providing a foundation for future MOF-based nanocarriers exploiting ligand–receptor interactions.

• Publisher: MDPI AG,Multidisciplinary Digital Publishing Institute (MDPI)
• Subject: ACE2 / ACE2 receptors / Adsorption / Aggregation behavior / Angiotensin / Angiotensin-converting enzyme 2 / Biocompatibility / Biomedical materials / Cysteine / cysteine functionalisation / Cytometry / Disease transmission / Electron microscopy / Fluorescence / Imaging / Metal-organic frameworks / metal–organic framework / Microporosity / Microscopy / Nanoparticles / Optical properties / Peptidyl-dipeptidase A / Polyethylene glycol / Proteins / Receptors / Severe acute respiratory syndrome coronavirus 2 / Software packages / Solvents / spike protein / targeted delivery / UiO-66(Zr)-NH2 / Viral infections / Zirconium