16.8 Internal Cargo Distribution and Localization

Internal Cargo Distribution and Localization describes how encapsulated molecular cargo is spatially arranged within a compartment's interior once incorporation has occurred, covering both cases where cargo spreads evenly throughout the available volume and cases where it concentrates in specific regions such as the membrane surface, an internal phase, or a bound scaffold. It treats spatial arrangement as a property distinct from the simple presence or absence of cargo, since two compartments with identical cargo copy number can nonetheless differ substantially in how that cargo is organized internally.

Basic Distribution Patterns

Uniform Internal Cargo Distribution

Uniform internal cargo distribution describes an arrangement in which cargo molecules are spread evenly throughout the compartment's available internal volume, with no particular region showing elevated or depleted concentration relative to any other.

Nonuniform Internal Cargo Distribution

Nonuniform internal cargo distribution describes an arrangement in which cargo molecules are unevenly spread throughout the compartment's interior, with certain regions showing elevated concentration and others showing depletion relative to the average.

Surface and Interface Localization

Cargo Membrane Adsorption

Cargo membrane adsorption describes cargo molecules that specifically associate with the inner surface of the compartment boundary, accumulating there rather than remaining distributed through the bulk interior, directly paralleling the general interface adsorption concept applied specifically to encapsulated cargo.

Cargo Interface Accumulation

Cargo interface accumulation describes cargo molecules that concentrate at any internal interface present within the compartment, such as the boundary between two internal phases in a nested or hybrid compartment, rather than solely at the outer boundary surface.

Bulk Interior Localization

Cargo Lumen Localization

Cargo lumen localization describes cargo that remains within the bulk aqueous interior rather than associating with any boundary or internal interface, representing the counterpart to surface and interface localization.

Cargo Phase Partitioning

Cargo phase partitioning describes cargo that distributes preferentially into one distinct internal phase over another when a compartment's interior contains more than one physically or chemically distinct region, such as the dense and dilute regions of a nested coacervate.

Cargo Coacervate Recruitment

Cargo coacervate recruitment describes cargo that becomes selectively concentrated within the dense phase of a coacervate-containing compartment, reflecting the broader macromolecule enrichment behavior characteristic of coacervate compartments applied specifically to a co-encapsulated cargo species.

Cargo Internal Scaffold Binding

Cargo internal scaffold binding describes cargo that becomes physically attached to a structural scaffold present within the compartment interior, localizing according to the scaffold's specific spatial arrangement rather than through simple diffusion-driven distribution.

Consequences of Nonuniform Arrangement

Cargo Spatial Segregation

Cargo spatial segregation describes an outcome in which two or more distinct cargo species become localized to separate regions within the same compartment, physically separating components that are nonetheless both present within the same overall interior.

Cargo Local Concentration Enrichment

Cargo local concentration enrichment describes the elevated concentration a cargo species can reach within a specific localized region, such as an adsorbed surface layer or a coacervate dense phase, relative to what its average concentration across the whole compartment volume would suggest.

Cargo Diffusion Restriction

Cargo diffusion restriction describes a reduction in how freely a localized cargo species can move throughout the compartment interior, arising when the cargo is bound to a surface, interface, or scaffold rather than diffusing unimpeded through the bulk lumen.

Persistence and Change Over Time

Internal Cargo Redistribution

Internal cargo redistribution describes a change in cargo spatial arrangement occurring after initial encapsulation, such as a shift from uniform distribution toward surface adsorption over time, reflecting that internal distribution is not necessarily fixed at the moment of incorporation.

Cargo Localization Stability

Cargo localization stability describes the degree to which an established spatial arrangement of cargo persists over time without further redistribution, determining whether a given localization pattern represents a durable feature of the compartment or a transient state likely to change.