Functional imaging

Fluorescence correlation spectroscopy (FCS)

Description
Fluorescence correlation spectroscopy (FCS) is a correlation analysis of fluctuations in the fluorescence intensity. The analysis provides information on physical parameters of the fluorescent particles (molecules) in solution, such as concentration, average fluorescence intensity and diffusion speed. By following changes on these parameters it is possible to study binding events of the molecules or even conformational changes on them.

Service provider
Advanced Light Microscopy Facility (ALMF)

Location
Heidelberg, Germany

Contacts
Scientific contact: Rainer Pepperkok
Technical contact: Stefan Terjung

Fluorescence cross-correlation spectroscopy (FCCS)

Description
Fluorescence cross-correlation spectroscopy (FCCS) extends the FCS procedure in that it looks at the correlation between different colors (cross-correlation) rather than just the same color (auto-correlation). In other words, coincident green and red intensity fluctuations correlate if green and red labeled particles are moving together. As a result, FCCS provides a highly sensitive measurement of molecular interactions independent of diffusion rate.

Service provider
Advanced Light Microscopy Facility (ALMF)

Location
Heidelberg, Germany

Contacts
Scientific contact: Rainer Pepperkok
Technical contact: Stefan Terjung

Fluorescence recovery after photobleaching (FRAP)

Description
Fluorescence recovery after photobleaching (FRAP) denotes an optical technique capable of quantifying the two-dimensional lateral diffusion of a molecularly thin film containing fluorescently labeled probes. This technique is very useful in biological studies of cell membrane diffusion and protein binding as it not only reports on the diffusion rates of mobile fractions of molecules but also provides information about the proportion of immobile molecules. In addition, surface deposition of a fluorescent phospholipid bilayer (or monolayer) allows the characterization of hydrophilic (or hydrophobic) surfaces in terms of surface structure and free energy.

Service provider I
Advanced Light Microscopy Facility (ALMF)

Location
Heidelberg, Germany

Contacts
Scientific contact: Rainer Pepperkok
Technical contact: Stefan Terjung

 

Service provider II
The Institute of Photonic Sciences (ICFO)

Location
Barcelona, Spain

Contacts
Scientific contact: Pablo Loza-Alvarez 
Technical contact: Jordi Andilla, Maria Marsal   

Fluorescence resonance energy transfer (FRET)

Description
Fluorescence resonance energy transfer (FRET) is a mechanism describing energy transfer between two light-sensitive molecules (chromophores). A donor chromophore, initially in its electronic excited state, may transfer energy to an acceptor chromophore through non-radiative dipole-dipole coupling. The efficiency of this energy transfer is inversely proportional to the sixth power of the distance between donor and acceptor, making FRET extremely sensitive to small changes in distance and therefore an excellent reporter on molecule proximity and interaction.

Service provider I
Advanced Light Microscopy Facility (ALMF)

Location
Heidelberg, Germany

Contacts
Scientific contact: Rainer Pepperkok
Technical contact: Stefan Terjung

 

Service provider II
The Institute of Photonic Sciences (ICFO)

Location
Barcelona, Spain

Contacts
Scientific contact: Pablo Loza-Alvarez 
Technical contact: Jordi Andilla, Maria Marsal   

Raman spectroscopy

Description
Raman spectroscopy is a spectroscopic technique based on inelastic scattering of monochromatic light, usually from a laser source. Inelastic scattering means that the frequency of photons in monochromatic light changes upon interaction with a sample.

Service provider
The Institute of Photonic Sciences (ICFO)

Location
Barcelona, Spain

Contacts
Scientific contact: Pablo Loza-Alvarez 
Technical contact: Jordi Andilla, Maria Marsal