Biology subjects

Poc, P.

Publications and source records attributed to Poc, P..

2 recordsLinked to original sources

bioRxiv2026

A modular HaloTag platform for engineering magnetically responsive bacterial microrobots

Functionalizing bacteria with magnetic nanoparticles (MNPs) is a common route toward magnetically responsive bacterial microrobots. However, existing strategies are often limited by low functionalization efficiency, weak binding, poor reproducibility, and nonspecific interactions. Here, we present a robust, specific, and reproducible magnetic functionalization platform based on the self-labeling protein HaloTag, yielding magnetic bacterial microrobots termed HaloBots. Using Escherichia coli as an engineering host, HaloTag was displayed on the outer membrane via the Lpp-OmpA anchoring system, with the assistance of a Long and Flexible (LF) peptide linker. Optimization of genetic engineering vectors and colony purification enabled robust and uniform HaloTag display across bacterial populations. In addition, MNPs were modified with chloroalkane-PEG ligands to enable site-specific covalent conjugation with HaloTag. Tuning the ligand density on MNPs revealed a critical balance between ligand accessibility and surface charge for achieving efficient and specific attachment. Consequently, the resulting HaloBots exhibited stable MNP conjugation and reliable magnetic actuation. Collectively, this work establishes a modular and tunable strategy for engineering magnetically responsive bacterial microrobots.

bioengineering↗

bioRxiv2020

Interrogating surface versus intracellular transmembrane receptor populations using cell-impermeable SNAP-tag substrates

Employing self-labelling protein tags for the attachment of fluorescent dyes has become a routine and powerful technique in optical microscopy to visualize and track fused proteins. However, membrane permeability of the dyes and the associated background signals can interfere with the analysis of extracellular labeling sites. Here we describe a novel approach to improve extracellular labeling by functionalizing the SNAP-tag substrate benzyl guanine ("BG") with a charged sulfonate ("SBG"). This chemical manipulation improves solubility, reduces non-specific staining and renders the bioconjugation handle impermeable while leaving its cargo untouched. We report SBG-conjugated fluorophores across the visible spectrum, which cleanly label SNAP-fused proteins in the plasma membrane of living cells. We demonstrate the utility of SBG-conjugated fluorophores to interrogate class A, B and C G protein-coupled receptors (GPCRs) using a range of imaging approaches including nanoscopic super-resolution imaging, analysis of GPCR trafficking from intra- and extracellular pools, in vivo labelling in mouse brain and analysis of receptor stoichiometry using single molecule pull down.

physiology↗