Jürgen Czarske

In vivo Brillouin microscopy of the larval zebrafish spinal cord (Conference Presentation)

The mechanical properties of biological tissues are increasingly recognized as crucial parts of signaling cascades involved in developmental and pathological processes. While most techniques measuring intrinsic mechanical properties necessitate invasive sample preparations or are currently applicable only to large sample dimensions, confocal Brillouin microscopy provides means to quantify the mechanical properties of single cells and tissues in a contact- and label-free manner. Here, we show for the first time a systematic application of confocal Brillouin microscopy to quantify physical properties of tissues in vivo. By using our custom-built Brillouin microscope, zebrafish larvae were probed in all anatomical planes, at different time points during development and after spinal cord injury. These experiments revealed that confocal Brillouin microscopy is capable of detecting the mechanical properties of distinct anatomical structures without interfering with the animal’s natural development. We furthermore detected an increasing Brillouin shift of spinal cord tissue during development and a transiently decreasing Brillouin shift after spinal cord injury. The presented work constitutes the first step towards an in vivo assessment of spinal cord tissue mechanics during regeneration, provides a basis to identify key determinants of mechanical tissue properties and allows to test their importance in combination with biochemical and genetic factors.

Analytische Modellierung der spektralen Verteilung der Rayleigh-Streuung zur Verringerung der Messunsicherheit bei der Bestimmung von Temperatur und Strömungsgeschwindigkeit

Die Messung von Temperatur- und Geschwindigkeitsfeldern spielt eine wichtige Rolle in der Energie- und Verfahrenstechnik, beispielsweise um den Wirkungsgrad von Kraftwerken zu steigern. Mit optischen Verfahren konnen hochaufgeloste Messungen von Stromungen vorgenommen werden, aber ublicherweise sind Partikel fur die Lichtstreuung einzubringen. In diesem Beitrag wird eine neuartige Methode vorgestellt, die keinerlei Streupartikel benotigt und eine gleichzeitige flachige Messung von Druck, Temperatur und Geschwindigkeit erlaubt. Die Methode basiert auf der spektralen Auswertung von gefilterter Rayleigh-Streuung. Die Reduzierung der Messunsicherheit mittels einer analytischen Modellfunktion und der Methode der kleinsten Fehlerquadrate wird dargelegt.

Undisturbed imaging through a dynamic gas-liquid boundary by wavefront manipulation

We present a technique for distortion-free laser-based measurements through a dynamic gas-liquid interface. Suitable components, methods and applications of the adaptive interferometric technique will be discussed by accomplished experiments and simulations.