Poly vinyl phosphonic acid (p(VPA)) hydrogel nanoparticles (nanogels) were prepared using VPA as monomer via microemulsion polymerization employing cetyl trimethylammonium bromide (CTAB) as a cationic surfactant. The nanogels were rendered magnetic field responsive by inclusion of silica-coated Fe3O4 nanoparticles during micro emulsion polymerization. Moreover, a porous nanogel was prepared by using triethoxyvinylsilane as co-monomer in microemulsion polymerization and removing the silica by HF treatment after polymerization. The synthesized nanogels were demonstrated as drug delivery devices in biomedical applications with targetable ability by using Zuclopenthixol (ZP) and phenazopyridine hydrochloride (PP) as model drugs. The ZP and PP loading and release amounts were evaluated via UV-Vis spectrometer (as a function of time at 324 nm and 426 nm, respectively) at different pHs such as 1.5, 7.4 and 9.0. Moreover, p(VPA) nanogels were shown to be very useful in environmental applications as absorbents for the removal of organic contaminants such as 4-nitrophenol (4 -NP), 1,1'-Dimethyl-4,4'-bipyridinium dichloride (Paraquat, PQ, Methylene Blue (MB) and Rhodamine 6G (R-6G) from aqueous media. (C) 2016 Elsevier Ltd. All rights reserved.