Secretion and Reversible Assembly of Extracellular-like Matrix by Enzyme-Active Colloidosome-Based Protocells

Abstract

The secretion and reversible assembly of an extracellular-like matrix by enzyme-active inorganic protocells (colloidosomes) is described. Addition of N-fluorenyl-methoxycarbonyl-tyrosine-(O)-phosphate to an aqueous suspension of alkaline phosphatase-containing colloidosomes results in molecular uptake and dephosphorylation to produce a time-dependent sequence of supramolecular hydrogel motifs (outer membrane wall, cytoskeletal-like interior and extra-protocellular matrix) that are integrated and remodelled within the microcapsule architecture and surrounding environment. Heat-induced disassembly of the extra-protocellular matrix followed by cooling produces colloidosomes with a densely packed hydrogel interior. These procedures are exploited for the fabrication of nested colloidosomes with spatially delineated regions of hydrogelation.

Colloidal capsules: nano- and microcapsules with colloidal particle shells

“…259 The authors also observed the formation of nanofilaments from the hydrogels which were further investigated in a subsequent study. 260 A primitive cell-like division process of silica protocells was also invented by Mann and co-workers. Here, colloidal capsules containing a sodium phosphate buffer solution in a continuous oil phase were produced.…”

Design and construction of artificial photoresponsive protocells capable of converting day light to chemical energy

“…To this end, we fabricated novel semi-permeable photoresponsive protocells via the encapsulation and activation of metallized peptide/porphyrin (I4K2/TPPS/Pt) fibrils within silica nanoparticle-stabilized colloidosomes capable of exhibiting a range of biomimetic and cell-like functions such as membrane gating, 10 enzyme-induced small molecule signaling, 11 in situ gene expression, 12 enzyme-mediated catalysis, 10,12,13 capsule growth and division, 14 and enzyme-directed secretion of an extracellular-like matrix. 15 Encapsulation of the photoactive I4K2/TPPS/Pt complex within the colloidosomes produced photoresponsive protocells that exhibited efficient coordination of light capture and electron transfer as demonstrated by the conversion and storage of day light (700 lux) into chemical energy in the form of NADH production within the colloidosomes. aqueous dispersion of I4K2/TPPS/Pt nanofilaments.…”

Phagocytosis-inspired behaviour in synthetic protocell communities of compartmentalized colloidal objects

“…[6][7][8] Biomolecules such as genetic polymers and enzymes were encapsulated into the nanoparticle-stabilized aqueous droplets (water-in-oil Pickering emulsions [9][10][11][12], and the silica membrane was cross-linked in oil to produce colloidosomes in the form of robust, semi-permeable microcapsules that could be transferred into water. 6 A range of protocellular functions were subsequently demonstrated, including in situ gene expression, 6 enzyme-mediated catalysis, 6,8,13 microcapsule growth and division, 7 membrane gating, 8 enzymedirected secretion of an extracellular-like matrix, 14 and enzyme-induced small-molecule signalling. 15 The above studies, along with diverse investigations on alternative protocell models, [16][17][18][19][20][21][22][23][24] have focused primarily on the integration of functional components into individual microcompartmentalized constructs.…”