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Hydrogels are interesting materials as delivery systems of various therapeutic agents, mainly due to the water-swollen network and the localized and sustained drug release. Herein, single-component starch-based hydrogels with enhanced degradation rates were produced by applying a facile synthesis and proposed for a novel delivery system of therapeutic molecules. Starch was oxidized with sodium periodate in water and mild conditions to generate aldehyde derivatives that, after a freeze-thaw procedure, were allowed to compact and stable hydrogels. Oxidized starch was also cross-linked with asparagine through a Schiff base reaction to link the active molecule directly to the polysaccharide structure. The materials were structurally and morphologically characterized, and the ability to adsorb and release over time an active molecule was proven by qNMR spectroscopy. The cytotoxicity was evaluated on CAL-27 cell line (oral squamous cell carcinoma). Results indicated that synthesized hydrogels lead to a "frozen proliferative" state on cells due to the swelling capability in the cell medium. This behavior was confirmed by flow cytometry data indicating the hydrogels induced less "early apoptosis" and more "late apoptosis" in the cells, compared to the untreated control. Since the proposed materials are able to control the cell proliferation, they could open a new scenario within the field of precise therapeutic applications. [ABSTRACT FROM AUTHOR]

The reactivity of Morita–Baylis–Hillman Adduct (MBHA) derivative 7 was studied with different primary amine derivatives such as n‐butylamine, Nα‐acetyl‐L‐lysine methyl ester, and a poly‐(L‐lysine) derivative as lysine models to obtain information about the possible reactions in complex protein environments. MBHA derivative 7 reacted with n‐butylamine or Nα‐acetyl‐L‐lysine methyl ester producing monoadducts 9a or 9c, which showed bright emission features in the green region at 526–535 nm with photoluminescence quantum yield values in solutions of 73 % and 51 %, respectively. Based on these results, MBHA derivative 7 can be considered an interesting new fluorogenic probe potentially useful in the labelling of basic amino acid residues. Furthermore, similar to other MBHA derivatives, compound 7 showed the tendency to produce diadducts especially in polar solvents system where specific interactions between the extended aromatic moieties may play a major role. [ABSTRACT FROM AUTHOR]

Some syndiotactic-rich polyolefins, generally difficult to synthesize through stereospecific polymerization of the corresponding monomers, were prepared by homogeneous non-catalytic hydrogenation of syndiotactic 1,2 poly(1,3-diene)s with diimide, arising from thermal decomposition of p-toluene-sulfonyl-hydrazide. All the polymers synthesized were structurally characterized by means of several analytical techniques, such as FT-IR, NMR (1H, 13C and 2D), DSC, and GPC, and herein illustrated. [ABSTRACT FROM AUTHOR]

Contamination of the aqueous environment caused by the presence of heavy metal ions and oils is a growing concern that must be addressed to reduce their detrimental impact on living organisms and safeguard the environment. Recent efficient and environmentally friendly remediation methods for the treatment of water are based on third-generation bioaerogels as emerging applications for the removal of heavy metal ions and oils from aqueous systems. The peculiarities of these materials are various, considering their high specific surface area and low density, together with a highly porous three-dimensional structure and tunable surface chemistry. This review illustrates the recent progress in aerogels developed from cellulose and chitosan as emerging materials in water treatment. The potential of aerogel-based adsorbents for wastewater treatment is reported in terms of adsorption efficacy and reusability. Despite various gaps affecting the manufacturing and production costs of aerogels that actually limit their successful implementation in the market, the research progress suggests that bio-based aerogels are ready to be used in water-treatment applications in the near future. [ABSTRACT FROM AUTHOR]

Aerogels have recently started to be considered as "advanced materials"; therefore, as a general consideration, aerogels' toxicity testing should focus on their functionality which resides in their nanoscale open internal porosity. To assess the hazards of organic aerogels, testing at three levels may characterize their biophysical, in vitro and in vivo toxicity, defining distinct categories of aerogels. At the first level of testing, their abiotic characteristics are investigated, and the best aerogel(s) is forwarded to be tested at level 2, wherein in vitro methodologies may mainly evaluate the aerogels' cellular behavior. Within level 2 of testing, the main characteristics of toxicity are investigated and the selected aerogels are introduced to in vivo animal models at level 3. In the animal model testing, target organs are investigated along with systemic parameters of toxicity. Some study cases are presented for organic or anorganic aerogels. Within this tiered workflow, aerogels-based materials can be tested in terms of human health hazard. [ABSTRACT FROM AUTHOR]

Novel allyl cobalt complexes, i.e., (η³-C4H7)(η4-C4H6)Co(PCyPh2) (1), (η³-C4H7)(η4-C4H6)Co(PMePh2) (2) and (η³-C5H9)(η4-C5H8)Co(PMePh2) (3), were synthesized by reacting CoCl2(PRPh2)2 (R = methyl, cyclohexyl) with 1,3-butadiene or isoprene in presence of metallic zinc. The complexes were fully characterized by Nuclear Magnetic Resonance (NMR) spectroscopy (¹H and 2D experiments); in case of 1, single crystals, suitable for X-ray analysis, were obtained and the molecular structure was determined. The allyl cobalt phosphine complexes alone gave highly crystalline 1,2 polymers from 1,2-propadiene, but they did not polymerize 1,3-dienes. Nevertheless, in the presence of a stoichiometric amount of methylaluminoxane (MAO), they were able to polymerize 1,3-butadiene and substituted 1,3-butadienes such as isoprene, (E)-1,3-pentadiene, (E)-1,3-hexadiene, and (E)-3-methyl-1,3-pentadiene. Specifically, 1/MAO gave predominantly syndiotactic 1,2 polymers from 1,3-butadiene and terminally substituted 1,3-butadienes (e.g., 1,3-pentadiene and 1,3-hexadiene), but it was practically not active in the polymerization of internally substituted 1,3-butadienes (e.g., isoprene and 3-methyl-1,3-pentadiene); 2/MAO and 3/MAO exhibited instead an opposite behavior, giving predominantly isotactic 1,2 polymers from 3-methyl-1,3-pentadiene, and showing very low activity in the polymerization of 1,3-butadiene, 1,3-pentadiene and 1,3-hexadiene. The results obtained are interesting from the mechanistic point of view, and some hypotheses to explain this particular behavior were formulated. [ABSTRACT FROM AUTHOR]

The homogeneous non-catalytic hydrogenation of cis-1,4 poly(isoprene), isotactic cis-1,4 poly(1,3-pentadiene) and syndiotactic cis-1,4 poly(1,3-pentadiene) with diimide, formed by thermal decomposition of para-toluenesulfonylhydrazide, is examined. Perfectly alternating ethylene/propylene copolymers having different tacticity (i.e., isotactic and syndiotactic), which are difficult to synthesize by stereospecific copolymerization of the corresponding monomers, are obtained. Both isotactic and syndiotactic alternating ethylene/propylene copolymers are amorphous, with very low glass transition temperatures. [ABSTRACT FROM AUTHOR]

A new polymer brush was synthesized by spontaneous polymerization of benzofulvene macromonomer 6-MOEG-9-T-BF3k bearing a nona(ethylene glycol) side chain linked to the 3-phenylindene scaffold by means of a triazole heterocycle. The polymer structure was studied by SEC-MALS, NMR spectroscopy, and MALDI-TOF MS techniques, and the results supported the role of oligomeric initiatory species in the spontaneous polymerization of polybenzofulvene derivatives. The aggregation features of high molecular weight poly-6-MOEG-9-T-BF3k-FE were investigated by pyrene fluorescence analysis, dynamic light scattering studies, and transmission electron microscopy, which suggested a tendency towards the formation of spherical objects showing dimensions in the range of 20–200 nm. Moreover, poly-6-MOEG-9-T-BF3k-FE showed an interesting cytocompatibility in the whole concentration range tested that, besides its aggregation features, makes this polybenzofulvene brush a good polymer candidate for nanoencapsulation and delivery of drug molecules. Finally, the photo-physical features of poly-6-MOEG-9-T-BF3k-FE could allow the biodistribution of the resulting drug delivery systems to be monitored by fluorescence microscopy techniques. [ABSTRACT FROM AUTHOR]

Contamination of the aqueous environment caused by the presence of heavy metal ions and oils is a growing concern that must be addressed to reduce their detrimental impact on living organisms and safeguard the environment. Recent efficient and environmentally friendly remediation methods for the treatment of water are based on third-generation bioaerogels as emerging applications for the removal of heavy metal ions and oils from aqueous systems. The peculiarities of these materials are various, considering their high specific surface area and low density, together with a highly porous three-dimensional structure and tunable surface chemistry. This review illustrates the recent progress in aerogels developed from cellulose and chitosan as emerging materials in water treatment. The potential of aerogel-based adsorbents for wastewater treatment is reported in terms of adsorption efficacy and reusability. Despite various gaps affecting the manufacturing and production costs of aerogels that actually limit their successful implementation in the market, the research progress suggests that bio-based aerogels are ready to be used in water-treatment applications in the near future.

The introduction of inorganic materials into biopolymers has been envisioned as a viable option to modify the optical and structural properties of these polymers and promote their exploitation in different application fields. In this work, the growth of Al 2 O 3 in freestanding ∼30-μm-thick poly(butylene succinate) (PBS) films by sequential infiltration (SIS) at 70 °C via trimethylaluminum (TMA) and H 2 O precursors was investigated for the first time. The incorporation of Al 2 O 3 into the PBS matrix was clearly demonstrated by XPS analysis and SEM-EDX cross-sectional images showing a homogeneous Al 2 O 3 distribution inside the PBS films. Raman measurements on infiltrated freestanding PBS show a reduction of the signal related to the ester carbonyl group as compared to pristine freestanding PBS films. Accordingly, FTIR and NMR characterization highlighted that the ester group is involved in polymer-precursor interaction, leading to the formation of an aliphatic group and the concomitant rupture of the main polymeric chain. Al 2 O 3 mass uptake as a function of the number of SIS cycles was studied by infiltration in thin PBS films spin-coated on Si substrates ranging from 30 to 70 nm. Mass uptake in the PBS films was found to be much higher than in standard poly(methyl methacrylate) (PMMA) films, under the same process conditions. Considering that the density of reactive sites in the two polymers is roughly the same, the observed difference in Al 2 O 3 mass uptake is explained based on the different free volume of these polymers and the specific reaction mechanism proposed for PBS. These results assessed the possibility to use SIS as a tool for the growth of metal oxides into biopolymers, paving the way to the synthesis of organic-inorganic hybrid materials with tailored characteristics., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)