Departamento de Física

Facultad de Ciencia
Universidad de Santiago de Chile

Seminario de Física - Viernes 19 de Mayo - 2:00 PM - Sala de Conferencias

05/19/2017 - 14:00
Este viernes 19 de mayo, a las 14:00 hrs.
Quedan todos cordialmente invitados a asistir a esta interesante charla. 
Título: "Magnetic nanoparticles and carbon quantum dots for protein sensing: synthesis, characterization and the development of a chemical 'nose-tongue' strategy"
Dr. Rafael Freire de la Universidade Federal do Ceará
In this work, mixed ferrites of general formula M0.5Zn0.5Fe2O4 (M=Mn or Ni) were first investigated. Therefore, the hydro/solvothermal synthesis of these magnetic nanoparticles was performed under different conditions (solvent, reaction time and base concentration). Based on the magnetic properties of the two MNPs investigated, the mixed ferrite of formula Mn0.5Zn0.5Fe2O4 (MnZn) synthesized using water showed the greatest potential for sensing. Since among all synthesized MNPs, this sample displayed the highest saturation magnetization  value, lower crystallite size around 12 nm and superparamagnetic behavior. Once the first part of the doctoral thesis was concluded, the next step was to find a fluorescence probe. In this regard, it was performed the synthesis, as well as the application of branched poliethylenimine-functionalized carbon quantum dots (CQDs.BPEI) for protein detection. These carbon-based NPs were found to be protein-responsive.  Since CQDs.BPEI were able to detect eight different proteins (four metallic and four non-metallic) even using concentrations in the range of 5 – 40 nM. To further check the potential of the CQDs.BPEI, it was developed a “nose”-based methodology to identify proteins. Using materials as cheap as Cu2+ and ethylenediaminetetraacetic acid, the chemical “nose” approach was able to discriminate six different proteins at 40 nM concentration in phosphate buffered saline (PBS, pH 7.4). The identification accuracy of the random unknown set was 90% with all misclassification occurring for albumin proteins (e.g., Bovine Serum Albumin and Human Serum Albumin). The displayed results evidence the great potential of CQDs.BPEI as a protein-responsive probe to detect and identify proteins. Taken together, MnZn and CQDs.BPEI may be capable to build up a powerful protein sensing approach.    

Viernes 19 de Mayo 2017 a las 14:00 hrs.
Sala de Conferencias, 3er Piso
Departamento de Física
Universidad de Santiago