A nanoencapsulated bioactive macromolecule or bioactive macromolecule cluster, consisting essentially of: (a) a disintegratable nanocapsule having a core/shell structure, wherein the shell of said nanocapsule is made of hybrid organosilica material comprising a three-dimensional framework of Si-O bonds, wherein at least a subset of Si atoms in the material's framework are connected to at least another Si atom in the framework through a linker having the following structure: *-R 1 -L-R 2 -*; wherein: each occurrence of * denotes a point of attachment to a Si atom in the material's framework; L represents a responsively cleavable covalent bond, and R 1 and R 2 independently represent an optionally substituted C1-20alkylenyl moiety, an optionally substituted C1-20heteroalkylenyl moiety, an optionally substituted ethylenyl moiety, -C≡C- or an optionally substituted phenyl moiety, wherein the C1-20alkylenyl, C1-20heteroalkylenyl or ethylenyl moiety may bear one or more substituents selected from halogen or -OR where R may represent H or C1-6alkyl, and the phenyl moiety may bear one or more substituents independently selected from halogen, C1-6alkyl, -NO 2, -CN, isocyano, -OR p, -N(R p) 2 wherein each occurrence of R p independently represents H or C1-6alkyl; and (b) a bioactive macromolecule or bioactive macromolecule cluster encapsulated within said nanocapsule, wherein the bioactive macromolecule(s) within the nanocapsule is/are in an active conformation; and wherein the nanocapsule inner core does not contain a micellar phase. (a) a disintegratable nanocapsule having a core/shell structure, wherein the shell of said nanocapsule is made of hybrid organosilica material comprising a three-dimensional framework of Si-O bonds, wherein at least a subset of Si atoms in the material's framework are connected to at least another Si atom in the framework through a linker having the following structure: *-R 1 -L-R 2 -*; wherein: each occurrence of * denotes a point of attachment to a Si atom in the material's framework; L represents a responsively cleavable covalent bond, and R 1 and R 2 independently represent an optionally substituted C1-20alkylenyl moiety, an optionally substituted C1-20heteroalkylenyl moiety, an optionally substituted ethylenyl moiety, -C≡C- or an optionally substituted phenyl moiety, wherein the C1-20alkylenyl, C1-20heteroalkylenyl or ethylenyl moiety may bear one or more substituents selected from halogen or -OR where R may represent H or C1-6alkyl, and the phenyl moiety may bear one or more substituents independently selected from halogen, C1-6alkyl, -NO 2, -CN, isocyano, -OR p, -N(R p) 2 wherein each occurrence of R p independently represents H or C1-6alkyl; and each occurrence of * denotes a point of attachment to a Si atom in the material's framework; L represents a responsively cleavable covalent bond, and R 1 and R 2 independently represent an optionally substituted C1-20alkylenyl moiety, an optionally substituted C1-20heteroalkylenyl moiety, an optionally substituted ethylenyl moiety, -C≡C- or an optionally substituted phenyl moiety, wherein the C1-20alkylenyl, C1-20heteroalkylenyl or ethylenyl moiety may bear one or more substituents selected from halogen or -OR where R may represent H or C1-6alkyl, and the phenyl moiety may bear one or more substituents independently selected from halogen, C1-6alkyl, -NO 2, -CN, isocyano, -OR p, -N(R p) 2 wherein each occurrence of R p independently represents H or C1-6alkyl; and (b) a bioactive macromolecule or bioactive macromolecule cluster encapsulated within said nanocapsule, wherein the bioactive macromolecule(s) within the nanocapsule is/are in an active conformation; and