Multifunctional\nPhosphate-Based Inorganic–Organic\nHybrid Nanoparticles

Abstract

Phosphate-based\ninorganic–organic hybrid nanoparticles (IOH-NPs)\nwith the general composition [<i>M</i>]²⁺[<i>R</i>_{<i>function</i>}(O)­PO₃]^2– (<i>M</i> = ZrO, Mg₂O; <i>R</i> = functional organic group) show multipurpose and multifunctional\nproperties. If [<i>R</i>_{<i>function</i>}(O)­PO₃]^2– is a fluorescent dye anion\n([<i>R</i>_<i>dye</i>OPO₃]^2–), the IOH-NPs show blue, green, red, and near-infrared\nfluorescence. This is shown for [ZrO]²⁺[PUP]^2–, [ZrO]²⁺[MFP]^2–, [ZrO]²⁺[RRP]^2–, and [ZrO]²⁺[DUT]^2– (PUP = phenylumbelliferon phosphate, MFP = methylfluorescein phosphate,\nRRP = resorufin phosphate, DUT = Dyomics-647 uridine triphosphate).\nWith pharmaceutical agents as functional anions ([<i>R</i>_<i>drug</i>OPO₃]^2–), drug transport and release of anti-inflammatory ([ZrO]²⁺[BMP]^2–) and antitumor agents ([ZrO]²⁺[FdUMP]^2–) with an up to 80% load of active drug\nis possible (BMP = betamethason phosphate, FdUMP = 5′-fluoro-2′-deoxyuridine\n5′-monophosphate). A combination of fluorescent dye and drug\nanions is possible as well and shown for [ZrO]²⁺[BMP]^2–_0.996[DUT]^2–_0.004. Merging of functional anions, in general, results in [ZrO]²⁺([<i>R</i>_<i>drug</i>OPO₃]_1–<i>x</i>[<i>R</i>_<i>dye</i>OPO₃]_<i>x</i>)^2– nanoparticles and is highly relevant\nfor theranostics. Amine-based functional anions in [MgO]²⁺[<i>R</i>_<i>amine</i>PO₃]^2– IOH-NPs, finally, show CO₂ sorption\n(up to 180 mg g^–1) and can be used for CO₂/N₂ separation (selectivity up to α = 23). This\nincludes aminomethyl phosphonate [AMP]^2–, 1-aminoethyl\nphosphonate [1AEP]^2–, 2-aminoethyl phosphonate [2AEP]^2–, aminopropyl phosphonate [APP]^2–, and aminobutyl phosphonate [ABP]^2–. All [<i>M</i>]²⁺[<i>R</i>_{<i>function</i>}(O)­PO₃]^2– IOH-NPs are prepared\nvia noncomplex synthesis in water, which facilitates practical handling\nand which is optimal for biomedical application. In sum, all IOH-NPs\nhave very similar chemical compositions but can address a variety\nof different functions, including fluorescence, drug delivery, and\nCO₂ sorption.