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N-isopropylacrylamide (NIPAM) monomer undergoes phase separation in water at very high concentrations, which offers striking opportunities to engineer biphasic hydrogel systems. However, this is a metastable state and NIPAM evolves to crystallize. Besides, the concentration of NIPAM in the lower phase is very small. In this work we show that the aforementioned limitations can be overcome by the incorporation of selected components. Thus, the addition of acrylic acid enables accessing remarkably stable biphasic NIPAM-water systems, as corroborated by DSC (absence of NIPAM crystallization). The addition of a third monomer, diallyldimethylammonium chloride (DDAC), further allows modifying NIPAM partition notably. The phase-distribution of the components for different monomer mixtures was gauged by 1H NMR. Subsequent polymerization leads to the formation of biphasic hydrogels systems in a single step, whose phase morphology and temperature response (swelling response) has been characterized by SEM. This methodology also permits adjusting the crosslinker partition as a function of its nature, which can be used to tune the swelling behaviour of each phase for a certain composition.

A robust strategy is reported to build perfectly monodisperse star polycationscombining a trehalose-based cyclooligosaccharide (cyclotrehalan, CT) centralcore onto which oligoethyleneimine radial arms are installed. Thearchitectural perfection of the compounds is demonstrated by a variety ofphysicochemical techniques, including NMR, MS, DLS, TEM, and GPC. Key tothe strategy is the possibility of customizing the cavity size of the macrocyclicplatform to enable/prevent the inclusion of adamantane motifs. Theseproperties can be taken into advantage to implement sequential levels ofstimuli responsiveness by combining computational design, precisionchemistry and programmed host-guest interactions. Specifically, it is shownthat supramolecular dimers implying a trimeric CT-tetraethyleneimine starpolycation and purposely designed bis-adamantane guests are preorganizedto efficiently complex plasmid DNA (pDNA) into transfection-competentnanocomplexes. The stability of the dimer species is responsive to theprotonation state of the cationic clusters, resulting in dissociation at acidicpH. This process facilitates endosomal escape, but reassembling can takeplace in the cytosol then handicapping pDNA nuclear import. By equippingthe ditopic guest with a redox-sensitive disulfide group, recapturingphenomena are prevented, resulting in drastically improved transfectionefficiencies both in vivo and in vitro.

Poly(N-isopropylacrylamide-co-methacrylic acid) hydrogels were structured with hydrophobic compartments. To achieve that, N-isopropylacrylamide was copolymerized with methacrylic acid and a small percentage (~0.4 %mol) of (3,4-dihydroxy-5-nitrophenyl)methacrylamide (nitrocatechol monomer) in the presence of sodium dodecyl sulphate at a concentration below its CMC value. All the results support the structuring of poly(N-isopropylacrylamide-co-methacrylic acid) hydrogels with hydrophobic domains in water. These compartments were found to be rich in methacrylic acid and nitrocatechol units. Moreover, the structuring disappeared when hydrogels were swollen at pH 7.4. The structured hydrogel was capable of loading hydrophobic molecules (methyl-2-naphthoate and methyl-9-anthracenecarboxylate) as well as charged drugs (doxorubicin hydrochloride). This hydrogel permitted cell adhesion and growth as well as its detachment when the temperature fell below the LCST.

We have developed silica stabilized ferrimagnetic magnetite nanocubes (MNCs) as effective heat mediators for magnetic hyperthermia. To do that, large hydrophobic magnetite nanoparticles, with a mean size of 79 and 124 nm were synthesized and transferred to water by silica surface modification. The heating ability of these water suspensions was studied by measuring the Specific Power Absorption (SPA) applying an AC magnetic field of amplitude H0 = 45 kA/m and frequency f = 360 kHz. High SPA values were obtained, ranging from 560 to 1160 W/g. The normalization of the SPA values by the inverse of the frequency and squared field amplitude was performed in order to compare our results with these described in literature. The SPA value for our samples, normalized in this way, yielded values of 0.7-1.5 nH m2/kg.

A straightforward approach was proposed to decorate gold nanoparticles onto recyclable supports based on magnetite/polymer composite materials for highly efficient catalysis. Cross-linked particles bearing a controllable content of catechol active residues were synthesized by precipitation polymerization of mussel-inspired monomer, dopamine methacrylamide, and ethylene glycol dimethacrylate. The magnetite nanoparticles were also surface modified with dopamine derivatives to introduce vinyl or catechol groups. Then, the magnetite nanoparticles with vinyl groups were incorporated inside of the polymeric particles forming a magnetic core during the precipitation polymerization. As an alternative pathway to achieve these efficient catalytic systems, magnetic nanoparticles functionalized with dopamine were immobilized at the surface of the polymeric particles via Michael addition. Then, catechol redox chemistry was used to form and anchor gold nanoparticles on the surface of both synthesized magnetic supports. Subsequently, we investigated the catalytic activity and reusability of the magnetic composite catalysts toward the reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride. The systems with high gold content undergo great catalytic performance. Besides, the prepared catalysts can be easily recovered from the reaction mixture and reused several times.