Sacculations

Sacculations is a term used to describe the formation and expansion of sac-like compartments, called saccules, within a surrounding medium. It is used in theoretical biology, materials science, and computational models to study compartmentalization and vesicle formation. Etymology: from sacculus, Latin for “little bag,” with the suffix -tion.

Principles and mechanisms: Sacculation involves creation of enclosed luminal spaces that separate internal contents from the surrounding environment. Mechanisms include vesicle budding from membranes, invagination during growth, or phase separation that yields voids surrounded by a boundary layer. In materials systems, swelling-induced vesiculation and delamination can produce sac-like voids.

Types: Primary sacculation arises from homogeneous precursors forming sacs de novo; secondary sacculation results from reorganization of existing compartments; and dynamic sacculation refers to reversible, stimulus-responsive sac formation.

Functions: Sacculations can enable localized storage of materials, selective sequestration, and controlled release, or modulation of mechanical properties by introducing compliant chambers within a solid or gel.

Applications: In synthetic biology, sacculations enable compartmentalized metabolic reactions; in drug delivery, sacculated vesicles may act as carriers; in materials science, sacculated polymers create porosity for catalysis or filtration; in computer simulations, sacculation models help study morphogenesis.

Challenges: Controlling sac size and stability, permeability, and biocompatibility across scales; predicting behavior in complex environments.

See also: vesicle, sacculus, compartmentalization, phase separation, morphogenesis.