BioMark sensor Research, University of Coimbra
Dynamic Light Scattering (DLS)
Dynamic Light Scattering (DLS) is used to measure particle and molecule size. This technique measures the diffusion of particles moving under Brownian motion, and converts this to size and a size distribution using the Stokes-Einstein relationship.
The Zetasizer Nano ZS from Malvern is a high performance two angle particle and molecular size analyzer for the enhanced detection of aggregates and measurement of small or dilute samples, and samples at very low or high concentration using dynamic light scattering with ‘NIBS’ optics. The ZS also incorporates a zeta potential analyzer that uses electrophoretic light scattering for particles, molecules and surfaces, and a molecular weight analyzer using static light scattering. Therefore, it can be used for the measurement of protein size, electrophoretic mobility of proteins, zeta potential of colloids and nanoparticles, and optionally the measurement of protein mobility and microrheology of protein and polymer solutions.
The high performance of the Zetasizer Nano ZS also enables the measurement of the molecular weight and second virial coefficient, A2, of macromolecules and kD, the DLS interaction parameter. The system can also be used in a flow configuration to operate as a size detector for SEC or FFF.
Infrared Spectroscopy with Fourier Transform (FTIR)
Infrared spectroscopy is a type of absorption spectroscopy, in which absorbed energy is found in the infrared region of the electromagnetic spectrum. Like all other spectroscopic techniques, it can be used to identify a compound or investigate the composition of a sample. The term Fourier transform infrared spectroscopy derives from the fact that it is necessary to use the Fourier transform (a mathematical process) to convert the data collected in the radiation spectrum.
The laboratory features a iS20 DTGS FTIR from Thermo Scientific, equipped with an ATR (Attenuated Total Reflection) accessory with diamond and germanium crystals, allowing direct analysis of most samples, without prior preparation in most cases. This equipment can be used to obtain an infrared spectrum of a solid, liquid or gas compound, collecting high spectral resolution data over a wide spectral range, which is particularly useful to follow-up qualitative chemical properties of materials.
Microplate Reader
A microplate reader is a laboratory instrument that is used to measure chemical, biological or physical reactions, properties and analytes within the well of a microplate. A microplate consists of small wells in which separated reactions take place. These reactions convert the presence of an analyte or the progression of biochemical processes into optical signals. The microplate reader detects these signals and quantifies the parameter of interest.
Berthold Tecnologies TriStar² S supports the following wide range of detection modes:
- Absorbance (UV/VIS)
- Fluorescence Intensity (including FRET)
- Fluorescence Polarization
- Luminescence (including BRET and BRET2)
- Time Resolved Fluorescence
- Time Resolved FRET (TR-FRET/HTRF®)
Electroanalysis with modular potentiostat / galvanostat
Electroanalysis consists on the application of electrochemistry in the analysis of the phenomena associated with the separation processes of electric charges. Often this separation of charges leads to charge transfer, which can occur homogeneously in solution, or heterogeneously on the surface of the electrode. Electrochemical measurements may be performed for analytical purposes under equilibrium conditions (zero current) with potentiometric or off- equilibrium (current passing) with amperometric or voltammetric sensors.
The instrumentation that the laboratory has for this type of measurements are several portable PalmSens4 modular potentiostats / galvanostats/ impedance analyzers. The PalmSens4 has a large potential range (-5V to 5V or -10V to 10V) and current range (100 pA to 10 mA) with a high resolution and low noise. These equipment allow connection to conventional three-electrode systems, as well as printed electrode reading boxes and photovoltaic and fuel cells.
