Table 6.
Different strategies implemented into MSNs for achieving light-responsive drug delivery.
| Approach | Description | Reference | |
|---|---|---|---|
| Thermo-Responsive Disassembling Gatekeepers | |||
| DNA | Large DNA strands acting as gatekeepers that dehybridize above a certain temperature, triggering drug release | [231,384,385,386] | |
| Short DNA strands used as linkers for grafting bulky gatekeepers (proteins, small nanoparticles) that allow drug release when strands dehybridize upon heating | [387,388,389] | ||
| Peptides | Peptide sequences used as gatekeepers that self-assemble at physiological temperature and undergo disassembly when heated | [390,391,392] | |
| Heterodimeric peptide acting as gatekeeper that present a coiled coil conformation at physiological temperature. That 3D structure is lost when heat is applied, triggering drug release | [393] | ||
| Nanovalves | Supramolecular nanovalves attached to the surface through thermo-sensitive stalks | [394,395] | |
| LCST Polymers (Hydrophobic if T > LCST) | |||
| poly(urethane-amine) | LCST ca. 50 °C | Polymers form a polymeric network. Below LCTS hydrophilic chains hamper drug release. When T > LCTS, polymers become hydrophobic and the polymeric network shrinks, facilitating drug release. | [397] |
| p(MEO2MA-co-OEGMA) | LCST ca. 37 °C | [398] | |
| p(NIPAM) | LCST ca. 32 °C | [399,400] | |
| p(NIPAM-co-MPS) | LCST ca. 36 °C | [401,402] | |
| p(NIPAM-co-MAA) | LCST ca. 44 °C | [403,404] | |
| p(NIPAM-co-NHMA) | LCST ca. 42 °C | [137,405,406] | |
| UCST Polymers (Hydrophilic if T > UCST) | |||
| poly(acrylamide-co-acrylonitrile) | UCST ca. 42 °C | Polymers become hydrophilic above UCST, adopting an extended conformation that triggers drug release | [407] |
| p(NAGAm-co-NPhAm) | UCST ca. 45 °C | [408] | |