Harmonic modulation of acoustic standing wave fields for tissue engineering

Acoustic standing wave fields can be used to produce virtual, scaffold-less templates for tissue patterning and engineering. To date, only simple tissue patterns have been attempted and achieved such as layered microstructures. This is due in large part to the use of single-frequency standing waves transmitted from a single source, producing planar nodes and antinodes in the cell/growth medium suspension. The purpose of this study was to explore with computational models the possibility of generating complex tissue microstructures using multiple sources with multiple frequency capabilities. The models simulated multifrequency standing waves (i.e., modulated by higher harmonics), multiple acoustic sources at various angles to each other, and corresponding acoustic cavities. The simulations demonstrated that interference patterns of standing waves could be produced with a three-dimensional complexity similar to that of natural biological structures. Such patterns included alveolar structures (thin, membrane...