The inverted microscope, which has its light source and condenser above the stage pointing down and the objective and turret below the stage, has become ubiquitous for studying living cells and organisms at the bottom of tissue culture flasks and well plates without needing to remove the cells from their 'natural habitat' and place them on glass slides as is the case with the conventional microscope. According to Peter Drent, general manager of the biosciences group at Nikon Instruments Europe, the company's new range of Nikon microscopes has taken all the good points from its previous platform the TE2000 and made them work faster and more efficiently. The Ti range features three models the Ti-S (specialisation), Ti-U (universal) and Ti-E (electronic) with the E-model being the top of the range system which is completely automated. "In the previous generation, theTE2000 range, we introduced a new concept with the perfect focus system (PFS) that automatically measures the distance between the objective lens and the object to ensure that the microscope is in focus - even over several days," said Drent. In keeping with Nikon's 'Cellology' philosophy that inspired the BioStation, the microscope can be fitted with a stage incubator that controls the temperature, humidity and CO2 content of the sample so that the cells stay in their optimum environment while imaging is conducted. The system readjusts the focus hundreds of times every second as well as letting you define multiple positions to focus on, ensuring that time-lapse photography across samples in 96 well plates could be fully automated. "The disadvantage with the old PFS was that it would take up on the optical channels in the microscopes, somewhat limiting the application of the technology," said Drent. "In the new system we have built the PFS into the nosepiece of the system so that it doesn't take up a channel expanding the number of applications that the system can be used for." The system has also combined the source for fluorescence experiments with TIRF (total internal reflection fluorescence) so that a photo-activation unit can be mounted at the same time as the fluorescence unit to study PA-GFP (photo-activatable green fluorescent protein). Another feature of the new system is that it can dramatically speed up a 17 minute experiment by a clever optimisation of the systems movements so that it will now only take 7.5 minutes. "Automation movements usually work in a sequential manner and this takes up a lot of time, but the new Ti system uses simultaneous movements to reduce the time between the acquisition of different images," said Drent. The other major advance that has been incorporated into the new system is the addition of an external phase unit. Typically these phase units are incorporated into the objective lens to increase the phase contrast of the optical image. However, they tend to cut out between 10 to 15 per cent of the light. While this is not an issue during standard optical imaging, it can be very important to capture every photon when conducting fluorescent imaging experiments to monitor very infrequent cellular events. The Ti microscopes incorporate the phase ring into a conjugate plain of the microscope so that the sensitive camera can detect 100 per cent of the photons produce, while enabling the phase contrast to be seen through the eye piece. The new Ti range is available at similar prices to the previous TE2000 systems while improving the performance of the system. "Use of our inverted microscopes has led to some of the most exciting scientific breakthroughs of the twenty-first century. We are confident that this legacy will be continued and that further important discoveries will be made possible with our newest platform the Ti series," said Robert Forster, general manager of Nikon Instruments, UK.