Progress in gene- and biotechnology has opened a new application domain of optics - i.e. biophotonics. In this field,
optical methods are developed and applied to the functional analysis of tissues and cells as well as to cell manipulation.
Growth processes, e.g. in the developing stage of tumours, reveal themselves through changes in their elasticity
properties and by micro movements. Holographic-interferometric methods have proven their capability to analyse local
elasticity distribution and micro movements. In combination with microscopic optics, these "microinterferometric"
methods provide a new basic technology - i.e. Digital Holographic Phase Contrast Microscope - for the analysis,
manipulation and utilisation of living systems down to the nanoscale. Modular digital holographic microscopy allows
maker-free, quantitative, contactless, fast, full field, high resolving (< 5 nm axially) imaging and analysis of living cells
and can be combined simultaneously with most of the modern microscopic technologies. In this way, diagnostics
standards for cell differentiation and manipulation as well as for cellular tissue engineering and other life sciences
domains can be extended.