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Biology subjects

Visser, E. W.

Publications and source records attributed to Visser, E. W..

2 recordsLinked to original sources

Automated and Simulation-Guided Multiplexed DNA-PAINT for Nanoparticle Characterization

Recent advances in lab automation have dramatically increased the throughput of material synthesis, enabling rapid screening of nanomaterials for specific applications in nanotechnology and nanomedicine. However, this progress highlights a key bottleneck: most high-resolution characterization techniques, such as electron microscopy, atomic force microscopy (AFM), and super-resolution microscopy, remain low-throughput and labor-intensive. To keep pace, characterization must evolve toward greater automation and scalability. Here, we present an integrated and automatable workflow for multicolor DNA point accumulation for imaging in nanoscale topography (DNA-PAINT) super-resolution microscopy tailored for nanoparticles. Our approach combines kinetic simulations, automated multiplexed imaging, and streamlined image analysis to enable end-to-end automation, from experimental design to quantitative data output. Simulations predict optimal experimental conditions, thus reducing the need for manual optimization. A fluidics system paired with a TIRF microscope is used to automate multiplexed imaging by rounds of imaging and probe exchange (exchange-PAINT) on multiple memorized positions without human oversight during the acquisition process. Finally, an image analysis pipeline tailored for NPs allows for the quantification of nanoparticle size and multiplexed ligand functionalization. This methodology improves the throughput and reproducibility of single-molecule localization microscopy (SMLM) using DNA-PAINT and lowers the entry barrier for non-expert users, thus paving the way for broader adoption in nanomedicine and materials discovery workflows.

biophysics↗

Molecular mechanism of thyroxine transport by monocarboxylate transporters

Thyroid hormones (the common name for prohormone thyroxine and the bioactive form triiodothyronine) control major developmental and metabolic processes. Release of thyroid hormones from the thyroid gland into the bloodstream and their transport into target cells is facilitated by plasma membrane transporters, of which monocarboxylate transporter (MCT)8 and the highly homologous MCT10 are most important. Patients with MCT8 mutations suffer from a severe neurodevelopmental and metabolic disorder, however, the molecular mechanism underlying thyroid hormone transport is unknown. Using cryogenic-sample electron microscopy (cryo-EM), we determined the ligand-free and thyroxine-bound human MCT8 structures in the outward-open state and the thyroxine-bound human MCT10 in the inward-facing state. Our structural analysis revealed a network of conserved gate residues involved in conformational changes upon thyroxine binding, triggering ligand release on the opposite compartment. We then determined the structure of a folded, but inactive patient-derived MCT8 mutant, indicating a subtle conformational change which explains its reduced transport activity. In addition, we determined the structure of MCT8 bound to its inhibitor silychristin, revealing an interaction with residues essential to drive transition to the inward-facing state, thereby locking the protein in the outward-facing state. This study provides molecular and structural insights into normal and disordered thyroid hormone transport.

biochemistry↗