In biology, a filament is a "long chain of proteins, such as those found in hair, muscle, or in flagella". They are often bundled together for strength and rigidity. Some cellular examples include:
Filaments are also highly dynamic in nature and far from a static structure that acts as a stable "scaffold" for a cell. Some phenomena that profile a protein filaments' dynamics are:
References
Protein filament Wikipedia(Text) CC BY-SA