Graphene magnetic beads

Graphene beads (MaGO - MarGO)

Graphene-doped magnetic beads for separation and purification (MaGO)

Applications: Separation and purification of basic dyes and aromatic molecules

 

Immagina MaGO beads have a magnetic core embedded in an agarose structure. Beads are doped with Graphene Oxide or Reduced Graphene Oxide. MaGO are spherical beads with dimensions of about 50 µm. The adsorption capacity of MaGO sample was tested using a set of aromatic positively charged dyes (Nile Blue, Methylene Blue, Rhodamine 6G, and Crystal Violet). The results are reported in Figure 1. All the molecules tested showed a high value of adsorption capacity and a very fast adsorption kinetics.

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Figure 1.Up: UV-visible spectroscopy of the NB, CV, MB, and Rh6G dyes solutions and the supernatants after absorption for 1 minute with MaGO Table: Values of absorption capacity (Qt) and the absorption time of the tested molecules.

TetramethylRhodamine molecules (TAMRA) and TAMRA-labelled antibody (IgG-TAMRA) incubated with MaGO beads for 5-10 seconds followed by magnetic separation of the beads (Figure 2). As revealed from the Uv-Vis absorption spectra and spectrofluorometric analysis, MaGO beads can efficiently remove the free dye while the TAMRA-labelled antibody is still in solution (< 10% reduction).

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Figure 2. A and B UV Vis of IgG-TAMRA and free TAMRA dye (black lines) incubated with MaGO beads followed by vortexing for 5 seconds (red lines). C and D. Fluorescence emission of of IgG-TAMRA and free TAMRA dye (black lines) incubated with MaGO beads followed by vortexing for 5 seconds (red lines).

Fast Protocol for free dye/protein separation

  • Vortex the MaGO beads tube for 30 seconds
  • Put the required MaGO beads volume in a new 1.5 mL tube
  • Place the tube on the magnet to separate the beads. Remove the supernatant
  • Resuspend the beads in your dye-protein mixture
  • Vortex for 5-10 seconds
  • Place immediately the tube on the magnet to separate the beads. Remove the supernatant enriched with your labelled protein
  • Discard the beads containing the free dye

 

Palladium decorated Graphene-doped magnetic beads for catalysis (MarGO-Xm)

 

Applications: Catalysis

Video of Methylene Blue reduction with Sodium Borohydride in water catalyzed by MarGO-Xm

Immagina MarGO-Xm beads are palladium-decorated graphene magnetic beads. Beads are functionalized with palladium nanoparticles. MarGO-Xm are spherical beads with dimensions of about 50 µm.
MarGO-Xm particles were tested as catalysts for the catalytic reduction of molecules by sodium boron hydride. These reactions in the absence of catalysts are very slow and require days to reach completion. The metallic nanoparticles present on the surface of the graphene can increase the speed of the reaction by several orders of magnitude. 4-Nitrophenol (4-NP), Congo red (CR), and Methylene Blue (MB) were chosen as models for testing the catalytic properties of the MarGO-Xm palladium beads. The Turnover Frequency (TOF) values of the aforementioned reactions are reported in Table 2. The efficiency in degradation of Rh6G, CR, MB and 4-NP compared with those reported in literature ranks MarGO-Pd among the more active catalyst.

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Table 2: TOF values of MarGO-Xm in different reaction.

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Figure 3. UV-Vis spectra of 4-NP reduction before (black) and 1 minute after the addition of the MarGO-Xm beads (red).

Standard Protocol

  • Vortex the MarGO-Xm beads tube for 5 seconds
  • Put the required MarGO-Xm beads volume in a new 1.5 mL tube
  • Place the tube on the magnet to separate the beads. Remove the supernatant
  • Resuspend the beads in your reaction mixture
  • Vortex for 5 seconds
  • Place the tube in a sonication bath and kept it until the reaction is complete, or alternatively mix with a thermomixer (do not use magnetic stirrer)
  • Place the tube on the magnet to separate the beads. Remove the supernatant to collect the product.
  • Discard the beads
Graphene beads (MaGO - MarGO)
IMMAGINA BioTechnology’s General Terms and Conditions