The development of an experimental setup capable of contrasting fluorescent materials by their recombinative lifetimes
in an imaging mode is discussed. Such materials might include molecular dyes and QDs. The system is comprised of a
standard upright microscope fitted with an imaging CCD, and a white light laser that illuminates a circular region within
the field of view with variable period excitation pulse trains. Different fluorescent species within this region absorb the
laser light and fluoresce with a recombination lifetime dependent on material composition and local environment.
Species with differing fluorescent lifetimes can be distinguished in an imaging mode by their contrasting intensity
response to the pulse train at the range of different pulse frequencies. The technique is discussed and applied to samples
containing both CdTe (705 nm) and CdSe (611 nm) QDs, showing contrast between long (70-100 ns) and (relatively)
short (25-35 ns) lifetime within an image.
The technical objective of this study has been to design, build and validate biocompatible hollow fiber implants based on
fluorescence with integrated biophotonics components to enable in fiber kinetic cell based assays. A human
osteosarcoma in vitro cell model fiber system has been established with validation studies to determine in fiber cell
growth, cell cycle analysis and organization in normal and drug treated conditions. The rationale for implant
development have focused on developing benchmark concepts in standard monolayer tissue culture followed by the
development of in vitro hollow fiber designs; encompassing imaging with and without integrated biophotonics.
Furthermore the effect of introducing targetable biosensors into the encapsulated tumor implant such as quantum dots for
informing new detection readouts and possible implant designs have been evaluated. A preliminary micro/macro
imaging approach has been undertaken, that could provide a mean to track distinct morphological changes in cells
growing in a 3D matrix within the fiber which affect the light scattering properties of the implant. Parallel engineering
studies have showed the influence of the optical properties of the fiber polymer wall in all imaging modes. Taken all
together, we show the basic foundation and the opportunities for multi-modal imaging within an in vitro implant format.