Integration of a superconducting nanowire single-photon detector into a confocal microscope for time-resolved photoluminescence (TRPL)-mapping: Sensitivity and time resolution.

This report highlights the combination of the MicroTime 100 upright confocal fluorescence lifetime microscope with a Single Quantum Eos Superconducting Nanowire Single-Photon Detector (SNSPD) system as a powerful tool for photophysical research and applications. We focus on an application in materials science, photoluminescence imaging, and lifetime characterization of Cu(InGa)Se2 (CIGS) devices intended for solar cells. We demonstrate improved sensitivity, signal-to-noise ratio, and time-resolution in combination with confocal spatial resolution in the near-infrared (NIR) range, specifically in the 1000-1300 nm range. The MicroTime 100-Single Quantum Eos system shows two orders of magnitude higher signal-to-noise ratio for CIGS devices' photoluminescence imaging compared to a standard NIR-photomultiplier tube (NIR-PMT) and a three-fold improvement in time resolution, which is now limited by the laser pulse width. Our results demonstrate the advantages in terms of image quality and time resolution of SNSPDs technology for imaging in materials science.

Factors influencing isolation of functional pancreatic rat islets.

Yields and function of isolated islets vary considerably in spite of the introduction of new or improved methods for isolation. In most studies, these variations have been attributed to inadequacies of the applied collagenase preparations. However, when we retrospectively analyzed our rat islet isolations, we found large variations in yield and function in spite of application of identical collagenase sources. Therefore, in the present study, we determined the effect of rat donor strain, the source of inhibition of proteolytic activity (by bovine serum albumin), and the culture conditions on yield and function. AO rats showed a twofold higher islet yield than Wistar and Lewis rats. However, a higher yield was not associated with a higher response on glucose load since this response was more pronounced with Lewis islets than with Wistar and AO islets. Rats with a higher weight donate more islets but have a lower insulin secretory capacity. Islet yield and function also vary with application of different sources of bovine serum albumin during digestion. Moreover, the culture conditions influence the functional survival of isolated rat islets. CMRL1066 preserves the insulin secretory capacity of rat islets better than RPMI1640. Finally, the number of islets surviving the culture is higher when 4 instead of 12 and 24 islets were applied per square centimeter. Our observations indicate that strain and weight of the rat donor, the source of bovine serum albumin, and the culture conditions of islets are pertinent factors in efficacious isolation of islets.