Threshold-triggered tracer particles

A tracer particle having a core-shell structure and having at least a reference function and a reporting function,

• wherein the particle comprises a core, a mesoporous shell layer and at least one diffusion resistant threshold-triggered hull encapsulating the core-shell structure,
• wherein the reference function, which is embedded in the core and/or in the mesoporous shell layer, serves to recognize the particle and as stable signal relative to the variable reporting function, the reference function being a fluorescent or luminescent marker,
• wherein the mesoporous shell layer includes the reporting function which changes irreversibly, depending on an experienced physical, chemical and/or biochemical parameter, the reporting function being a fluorescent or luminescent marker having a different excitation signal or emission signal than the reference function,
• wherein the hull encapsulating the core-shell structure is diffusion resistant until a specific threshold in the physical, chemical and/or biochemical parameter has been reached and which is stimuli-responsive triggered by the threshold, upon which the hull dissolves, becomes permeable or temporarily permeable, breaks or separates from the core-shell structure, inducing an irreversible change in the reporting function, and
• wherein the tracer particle further comprises a charged species, which is attached to the diffusion resistant threshold-triggered hull or which is integrated into the core and/or the mesoporous shell layer.