Lab‐in‐a‐Bead: Magnetic Janus Bead Probe for the Detection of Biomarkers in Blood

• Published in: Advanced materials interfaces Vol. 10; no. 34
• Main Authors: Gunatilake, Udara Bimendra, Caballe‐Abalos, Adriana, Garcia‐Rey, Sandra, Mercader‐Ruiz, Jon, Basabe‐Desmonts, Lourdes, Benito‐Lopez, Fernando
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 01.12.2023; Wiley-VCH
• Subjects: Actuation; Alginates; Biofouling; Biomarkers; blood; colorimetric glucose; Colorimetry; Erythrocytes; Ferromagnetism; Hydrogels; Iron oxides; Janus beads; Lab‐in‐a‐Bead; Magnetic fields; magnetic hydrogels; Magnetic properties; Microparticles; Nanoparticles; Nanotubes; Remote sensors; sensor scaffolds; Sensors; Titanium dioxide
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.202202459

Remotely handled miniaturized colorimetric sensor platforms with multiple functionalities are able to mimic conventional laboratory operations with reduced assets. The integration of a magnetic phase in a miniaturized hydrogel sensor system allows the manipulation of the sensor, under a magnetic field, in a programmable manner. However, dark color interferences from conventional magnetic phases (Fe3O4, Fe2O3, and Fe micro/nanoparticles) affect the signal readout, hindering the colorimetric response. Therefore, a novel Janus bead configuration is introduced and tested by the localized incorporation of ferromagnetic iron microparticles into a TiO2 nanotubes/alginate hydrogel bead biosystem, under an applied magnetic field. The so‐called hydrogel Janus bead shows both, magnetic translocation and biosensing properties in the same bead. These beads are used for the direct colorimetric analysis of biomarkers in blood. The surface of the Janus bead prevents the biofouling of red blood cells, keeping the sensor surface clean for accurate optical colorimetric analysis. Moreover, the external magnetic manipulation of the bead permits precise control of the time and position of the bead in the sample. Therefore, multiple functionalities are presented by a single magnetic TiO2 nanotubes/alginate Janus bead such as actuation, low biofouling, and sensing, positioning this technology as a truly Lab‐in‐a‐Bead System. A novel hydrogel‐based Janus bead is fabricated and tested by the localized incorporation of ferromagnetic iron microparticles to a TiO2 nanotubes/alginate hydrogel bead biosystem, under an applied magnetic field. The multiple functionalities of this novel Janus bead such as remote handling, magnetic manipulation, assay reagent immobilization and storage, red blood cells filtration, and biosensing demonstrate the concept of Lab‐in‐a‐Bead.