Angelo Nicosia
@unict.it
Department of Chemical Science
Università degli studi di Catania
Scopus Publications
Scopus Publications
Fabiana Vento, Angelo Nicosia, Lidia Mezzina, Domenico Franco, Roberto Zagami, Antonino Mazzaglia, and Placido Giuseppe Mineo
Elsevier BV
Lidia Mezzina, Angelo Nicosia, Laura Barone, Fabiana Vento, and Placido Giuseppe Mineo
MDPI AG
The development of nanotools for chemical sensing and macromolecular modifications is a new challenge in the biomedical field, with emphasis on artificial peptidases designed to cleave peptide bonds at specific sites. In this landscape, metal porphyrins are attractive due to their ability to form stable complexes with amino acids and to generate reactive oxygen species when irradiated by light of appropriate wavelengths. The issues of hydrophobic behavior and aggregation in aqueous environments of porphyrins can be solved by using its PEGylated derivatives. This work proposes the design of an artificial photo-protease agent based on a PEGylated mercury porphyrin, able to form a stable complex with l-Tryptophan, an amino acid present also in the lysozyme structure (a well-known protein model). The sensing and photodegradation features of PEGylated mercury porphyrin were exploited to detect and degrade both l-Trp and lysozyme using ROS, generated under green (532 nm) and red (650 nm) light lasers. The obtained system (Star3600_Hg) and its behavior as a photo-protease agent were studied by means of several spectroscopies (UV-Vis, fluorescence and circular dichroism), and MALDI-TOF mass spectrometry, showing the cleavage of lysozyme and the appearance of several short-chain residues. The approach of this study paves the way for potential applications in theranostics and targeted bio-medical therapies.
Angelo Nicosia, Placido Mineo, Norberto Micali, and Valentina Villari
MDPI AG
The development of biocompatible composites constituted by polydopamine and fluorescent carbon dots represents a promising way of exploiting the extraordinary adhesive properties of polydopamine for multi-purpose technologies. Here, a supramolecular complex is realized by the assembly of dopamine on the carbon dots surface, and the optical and structural properties are investigated by means of different spectroscopic techniques, from time-resolved fluorescence to Raman and NMR spectroscopies. The results suggest that the catechol unit of dopamine plays the main role in the formation of the supramolecular complex, in which carbon nanodot fluorescence emission is quenched by a photoinduced electron transfer process. The interaction with the nanodots’ basic surface sites promotes the oxidation of dopamine and drives to its oligomerization/polymerization on the nanodot surface.
Fabiana Vento, Angelo Nicosia, Lidia Mezzina, Giulia Raciti, Antonino Gulino, Marcello Condorelli, Luisa D'Urso, Guido De Guidi, and Placido Mineo
Wiley
Margherita Ferrante, Alfina Grasso, Gianluca Giuberti, Margherita Dall’Asta, Edoardo Puglisi, Giovanni Arena, Angelo Nicosia, Maria Fiore, and Chiara Copat
Elsevier BV
Fabiana Vento, Angelo Nicosia, Roberto Fiorenza, Salvatore Scirè, Anna Lucia Pellegrino, Lidia Mezzina, Giulia Raciti, and Placido Mineo
Wiley
AbstractIndustrial development and urbanization have increased the emission of Volatile Organic Compounds (VOCs) into the atmosphere, causing environmental and health risks. Several approaches are used for their abatement, including chemical, thermo‐ and photo‐catalytic oxidations, but they are not fully satisfactory. In this work, a thermoplastic TiO2‐based photo‐catalyst was used as a coating layer of a glass‐reactor. Solar‐triggered photocatalytic degradation of ethanol, toluene, and acetone (used as model VOCs) highlights the better performance of the coated photoreactor than that of TiO2 nanopowder. The influence of the pollutant flow rate on the photodegradation performance of the system was also investigated, revealing an inverse relationship between degradation and flow rates. The experimental data suggest that our approach provides a cost‐effective and efficient way to boost the abatement of VOCs, useful for further industrial‐scale applications. The morphology and the compositional homogeneity of the nanocomposite coating were addressed through Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X‐ray Analysis.
Angelo Nicosia, Giuseppe La Perna, Lorena Maria Cucci, Cristina Satriano, and Placido Mineo
MDPI AG
Polymer-based systems have been demonstrated in novel therapeutic and diagnostic (theranostic) treatments for cancer and other diseases. Polymers provide a useful scaffold to develop multifunctional nanosystems that combine various beneficial properties such as drug delivery, bioavailability, and photosensitivity. For example, to provide passive tumour targeting of small drug molecules, polymers have been used to modify and functionalise the surface of water-insoluble drugs. This approach also allows the reduction of adverse side effects, such as retinoids. However, multifunctional polymer conjugates containing several moieties with distinct features have not been investigated in depth. This report describes the development of a one-pot approach to produce a novel multifunctional polymer conjugate. As a proof of concept, we synthesised polyvinyl alcohol (PVA) covalently conjugated with rhodamine B (a tracking agent), folic acid (a targeting agent), and all-trans retinoic acid (ATRA, a drug). The obtained polymer (PVA@RhodFR) was characterised by MALDI-TOF mass spectrometry, gel permeation chromatography, thermal analysis, dynamic light-scattering, NMR, UV-Vis, and fluorescence spectroscopy. Finally, to evaluate the efficiency of the multifunctional polymer conjugate, cellular differentiation treatments were performed on the neuroblastoma SH-SY5Y cell line. In comparison with standard ATRA-based conditions used to promote cell differentiation, the results revealed the high capability of the new PVA@RhodFR to induce neuroblastoma cells differentiation, even with a short incubation time and low ATRA concentration.
Giulia Neri, Carmelo Iaria, Fabiano Capparucci, Gioele Capillo, Rosamaria Pennisi, Angelo Nicosia, Placido Giuseppe Mineo, Angela Scala, Maria Teresa Sciortino, Anna Piperno,et al.
Elsevier BV
Fabiana Vento, Angelo Nicosia, Lidia Mezzina, Gemma M. Rodríguez-Muñiz, Miguel A. Miranda, Placido G. Mineo, and Guido De Guidi
Elsevier BV
Lidia Mezzina, Angelo Nicosia, Giuseppe Antonio Baratta, Maria Elisabetta Palumbo, Carlotta Scirè, and Placido Giuseppe Mineo
MDPI AG
Space exploration missions are currently becoming more frequent, due to the ambition for space colonization in sight of strengthening terrestrial technologies and extracting new raw materials and/or resources. In this field, the study of the materials’ behaviour when exposed to space conditions is fundamental for enabling the use of currently existing materials or the development of new materials suitable for application in extra-terrestrial environments. In particular, the versatility of polymers renders them suitable for advanced applications, but the effects of space radiation on these materials are not yet fully understood. Here, to shed light on the effects of simulated solar wind on a polymeric material, polymethyl methacrylate (PMMA) was produced through radical bulk polymerization. The PMMA in the form of a thin film was subjected to proton beam bombardment at different fluences and in a high vacuum environment, with structural changes monitored through real-time FT-IR analysis. The structure of the residual material was investigated through MALDI-TOF mass spectrometry and 1H-NMR spectroscopy. The collected data allowed us to hypothesize the structural modifications of the PMMA and the related mechanisms.
Lidia Mezzina, Angelo Nicosia, Fabiana Vento, Guido De Guidi, and Placido Giuseppe Mineo
MDPI AG
Among different depollution methods, photocatalysis activated by solar light is promising for terrestrial outdoor applications. However, its use in underground structures and/or microgravity environments (e.g., extraterrestrial structures) is forbidden. In these cases, there are issues related to the energy emitted from the indoor lighting system because it is not high enough to promote the photocatalytic mechanism. Moreover, microgravity does not allow the recovery of the photocatalytic slurry from the depolluted solution. In this work, the synthesis of a filmable nanocomposite based on semiconductor nanoparticles supported by photosensitized copolyacrylates was performed through a bulk in situ radical copolymerization involving a photosensitizer macromonomer. The macromonomer and the nanocomposites were characterized through UV-Vis, fluorescence and NMR spectroscopies, gel permeation chromatography and thermogravimetric analysis. The photocatalytic activity of the sensitized nanocomposites was studied through photodegradation tests of common dyes and recalcitrant xenobiotic pollutants, employing UV-Vis and visible range (λ > 390 nm) light radiations. The sensitized nanocomposite photocatalytic performances increased about two times that of the unsensitized nanocomposite and that of visible range light radiation alone (>390 nm). The experimental data have shown that these new systems, applied as thin films, have the potential for use in indoor deep underground and extraterrestrial structures.
M. Cordaro, M. Trapani, M. A. Castriciano, J. A. A. W. Elemans, A. Nicosia, and P. Mineo
Georg Thieme Verlag KG
AbstractAn effective and convenient protocol for the synthesis of 1-substituted uracil-6-carbaldehyde derivatives has been developed. A three-step sequence permits the preparation of uracil-6-carbaldehydes with various substituents at the N-1 in large quantities by using low-cost precursors. The aldehyde-functionalized uracils served as useful precursors for the preparation of meso-(1-substituted 6-uracil)-derivatives of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY). In this way, regioselectively functionalized BODIPYs with a direct connection to a nucleobase were prepared in yields of 30–45%. MALDI-TOF mass spectrometry, NMR, UV/vis absorption, and steady-state and time-resolved fluorescence spectroscopies were used to characterize the structures and the spectroscopic/photophysical properties of the resultant dyes.
Valentina Villari, Norberto Micali, Angelo Nicosia, and Placido Mineo
Springer Science and Business Media LLC
This review arises from the need to rationalize the huge amount of information on the structural and spectroscopic properties of a peculiar class of porphyrin derivatives—the non-ionic PEGylated porphyrins—collected during almost two decades of research. The lack of charged groups in the molecular architecture of these porphyrin derivatives is the leitmotif of the work and plays an outstanding role in highlighting those interactions between porphyrins, or between porphyrins and target molecules (e.g., hydrophobic-, hydrogen bond related-, and coordination-interactions, to name just a few) that are often masked by stronger electrostatic contributions. In addition, it is exactly these weaker interactions between porphyrins that make the aggregated forms more prone to couple efficiently with external perturbative fields like weak hydrodynamic vortexes or temperature gradients. In the absence of charge, solubility in water is very often achieved by covalent functionalization of the porphyrin ring with polyethylene glycol chains. Various modifications, including of chain length or the number of chains, the presence of a metal atom in the porphyrin core, or having two or more porphyrin rings in the molecular architecture, result in a wide range of properties. These encompass self-assembly with different aggregate morphology, molecular recognition of biomolecules, and different photophysical responses, which can be translated into numerous promising applications in the sensing and biomedical field, based on turn-on/turn-off fluorescence and on photogeneration of radical species.
Angelo Nicosia, Fabiana Vento, Giovanni Marletta, Grazia M. L. Messina, Cristina Satriano, Valentina Villari, Norberto Micali, Maria Teresa De Martino, Maaike J. G. Schotman, and Placido Giuseppe Mineo
MDPI AG
The Spontaneous Symmetry Breaking (SSB) phenomenon is a natural event in which a system changes its symmetric state, apparently reasonless, in an asymmetrical one. Nevertheless, this occurrence could be hiding unknown inductive forces. An intriguing investigation pathway uses supramolecular aggregates of suitable achiral porphyrins, useful to mimic the natural light-harvesting systems (as chlorophyll). Using as SSB probe supramolecular aggregates of 5,10,15,20-tetrakis[p(ω-methoxypolyethyleneoxy)phenyl]porphyrin (StarP), a non-ionic achiral PEGylated porphyrin, we explore here its interaction with weak asymmetric thermal gradients fields. The cross-correlation of the experimental data (circular dichroism, confocal microscopy, atomic force microscopy, and cryo-transmission electron microscopy) revealed that the used building blocks aggregate spontaneously, organizing in flag-like structures whose thermally-induced circular dichroism depends on their features. Finally, thermal gradient-induced enantioselectivity of the supramolecular flag-like aggregates has been shown and linked to their size-dependence mesoscopic deformation, which could be visualized as waving flags in the wind.
Angelo Nicosia, Fabiana Vento, Gisella Maria Di Mari, Luisa D’Urso, and Placido G. Mineo
MDPI AG
Photocatalytic remediation represents a potential sustainable solution to the abatement of xenobiotic pollutants released within the water environment. Aeroxide® P25 titanium dioxide nanoparticles (TiO2 NPs) are well-known as one of the most efficient photocatalysts in several applications, and have also been investigated in water remediation as suspended powder. Recently, their application in the form of thin films has been revealed as a potential alternative to avoid time-consuming filtration processes. Polymers represent suitable substrates to immobilize TiO2 NPs, allowing further production of thin films that can be exploited as a photoactive coating for environmental remediation. Nevertheless, the methods adopted to immobilize TiO2 NPs on polymer matrix involve time-consuming procedures and the use of several reactants. Here, titanium dioxide-based nanocomposites (NCx) were obtained through a new approach based on Methyl Methacrylate in situ bulk polymerization and were compared with a blended mixture (BL). Their morphology and chemical–physical properties were investigated through Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), UV–Vis, and Raman spectroscopies. It was revealed that the in situ approach deeply influences the chemical–physical interactions between the polymer matrix and TiO2 NPs. Photocatalytic experiments revealed the boosted photodegradation activity of NCx thin films, induced by the in situ approach. The photodegradation of paraquat and acetaminophen was also ascertained.
Angelo Nicosia, Antonio Abbadessa, Fabiana Vento, Antonino Mazzaglia, and Placido Giuseppe Mineo
MDPI AG
Silver nanoparticles (AgNPs) stand out over other metal nanoparticles thanks to their peculiar bactericidal and spectroscopic properties. Tunability of the AgNPs chemical–physical properties could be provided through their organic covalent coating. On the other hand, PEGylated porphyrin derivatives are versatile heteromacrocycles investigated for uses in the biomedical field as cytotoxic and tracking agents, but also as sensors. In this work, an easy multi-step approach was employed to produce coated silver nanoparticles. Specifically, the AgNPs were functionalized with 5,10,15-[p-(ω-methoxy-polyethyleneoxy)phenyl]-20-(p-hydroxyphenyl)-porphyrin (P(PEG350)3), using chloropropanethiol as a coupling agent. The P(PEG350)3 was structurally characterized through MALDI-TOF mass spectrometry, NMR spectroscopy and thermal analyses. The functionalization of AgNPs was monitored step-by-step employing UV-Vis spectroscopy, dynamic light scattering and thermogravimetric techniques. HRTEM and STEM measurements were used to investigate the morphology and the composition of the resulting nanostructured system (AgNP@P(PEG350)3), observing a long-range alignment of the outer porphyrin layer. The AgNP@P(PEG350)3 combines the features of the P(PEG350)3 with those of AgNPs, producing a potential multifunctional theranostic tool. The nanosystem revealed itself suitable as a removable pH sensor in aqueous solutions and potentially feasible for biological environment applications.
Claudia Foti, Placido Giuseppe Mineo, Angelo Nicosia, Angela Scala, Giulia Neri, and Anna Piperno
Frontiers Media SA
The decontamination of water containing toxic metals is a challenging problem, and in the last years many efforts have been undertaken to discover efficient, cost-effective, robust, and handy technology for the decontamination of downstream water without endangering human health. According to the World Health Organization (WHO), 180 million people in the world have been exposed to toxic levels of arsenic from potable water. To date, a variety of techniques has been developed to maintain the arsenic concentration in potable water below the limit recommended by WHO (10 μg/L). Recently, a series of technological advancements in water remediation has been obtained from the rapid development of nanotechnology-based strategies that provide a remarkable control over nanoparticle design, allowing the tailoring of their properties toward specific applications. Among the plethora of nanomaterials and nanostructures proposed in the remediation field, graphene-based materials (G), due to their unique physico-chemical properties, surface area, size, shape, ionic mobility, and mechanical flexibility, are proposed for the development of reliable tools for water decontamination treatments. Moreover, an emerging class of 3D carbon materials characterized by the intrinsic properties of G together with new interesting physicochemical properties, such as high porosity, low density, unique electrochemical performance, has been recently proposed for water decontamination. The main design criteria used to develop remediation nanotechnology-based strategies have been reviewed, and special attention has been reserved for the advances of magnetic G and for nanostructures employed in the fabrication of membrane filtration.
Angelo Nicosia, Fabiana Vento, Anna Lucia Pellegrino, Vaclav Ranc, Anna Piperno, Antonino Mazzaglia, and Placido Mineo
MDPI AG
Nanocomposites obtained by the decoration of graphene-based materials with silver nanoparticles (AgNPs) have received increasing attention owing to their antimicrobial activity. However, the complex synthetic methods for their preparation have limited practical applications. This study aims to synthesize novel NanoHybrid Systems based on graphene, polymer, and AgNPs (namely, NanoHy-GPS) through an easy microwave irradiation approach free of reductants and surfactants. The polymer plays a crucial role, as it assures the coating layer/substrate compatibility making the platform easily adaptable for a specific substrate. AgNPs’ loading (from 5% to 87%) can be tuned by the amount of Silver salt used during the microwave-assisted reaction, obtaining spherical AgNPs with average sizes of 5–12 nm homogeneously distributed on a polymer-graphene nanosystem. Interestingly, microwave irradiation partially restored the graphene sp2 network without damage of ester bonds. The structure, morphology, and chemical composition of NanoHy-GPS and its subunits were characterized by means of UV-vis spectroscopy, thermal analysis, differential light scattering (DLS), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray analysis (EDX), Atomic Force Microscopy (AFM), and High-Resolution Transmission Electron Microscopy (HRTEM) techniques. A preliminary qualitative empirical assay against the typical bacterial load on common hand-contacted surfaces has been performed to assess the antibacterial properties of NanoHy-GPS, evidencing a significative reduction of bacterial colonies spreading.
Pascal Tomasella, Vanessa Sanfilippo, Carmela Bonaccorso, Lorena Maria Cucci, Giuseppe Consiglio, Angelo Nicosia, Placido Giuseppe Mineo, Giuseppe Forte, and Cristina Satriano
MDPI AG
In this study, graphene oxide (GO) and reduced-thiolated GO (rGOSH) were used as 2D substrate to fabricate nanocomposites with nanoparticles of gold nanospheres (AuNS) or nanorods (AuNR), via in situ reduction of the metal salt precursor and seed-mediated growth processes. The plasmonic sensing capability of the gold-decorated nanosheets were scrutinized by UV-visible (UV-VIS) spectroscopy. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analyses (TGA), and atomic force microscopy (AFM) were performed in order to prove the actual reduction that occurred concomitantly with the thiolation of GO, the increase in the hydrophobic character as well as the size, and preferential gathering of the gold nanoparticles onto the nanosheet substrates, respectively. Moreover, the theoretical electronic and infrared absorption (UV-VIS and IR) spectra were calculated within a time-dependent approach of density functional theory (DFT). Eventually, in vitro cellular experiments on human neuroblastoma cells (SH-SY5Y line) were carried out in order to evaluate the nanotoxicity of the nanocomposites by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reduction (MTT) colorimetric assay. Results pointed out the promising potential of these hybrids as plasmonic theranostic platforms with different hydrophilic or hydrophobic features as well as cytotoxic effects against cancer cells.
Angelo Nicosia, Fabiana Vento, Cristina Satriano, Valentina Villari, Norberto Micali, Lorena Maria Cucci, Vanessa Sanfilippo, and Placido Giuseppe Mineo
American Chemical Society (ACS)
A recent approach in the treatment of diseased cells/tissues is the use of smart, stimuli-responsive nanomaterials. Well-known examples include photosensitizer agents that after light irradiation at a specific wavelength generate singlet oxygen species (strongly cytotoxic) or self-assembled supramolecular structures, which blow up cancer cells by releasing their payload upon an external stimulus, thus making cancer cells swell and burst (so-called “nanobombs”). In this work we synthesized and characterized a polymeric star-like pentaporphyrin system (5P) that, depending on the photoexcitation wavelength selected, can act either as a photosensitizer or as a nanobomb. The 5P compound was characterized by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, nuclear magnetic resonance, UV–vis, and fluorescence spectroscopy techniques. The hydrodynamic size of the 5P compound in physiological buffer solution, as determined by dynamic light spectroscopy, pointed to the formation o...
Davide Gentile, Giuseppe Floresta, Vincenzo Patamia, Angelo Nicosia, Placido G. Mineo, and Antonio Rescifina
Royal Society of Chemistry (RSC)
The main objective of supramolecular chemistry is to mimic the macrosystems present in nature, a goal that fits perfectly with the green chemistry guidelines.
Norberto Micali, Placido Mineo, Fabiana Vento, Angelo Nicosia, and Valentina Villari
American Chemical Society (ACS)
Supramolecular nanostructures are obtained in aqueous solutions by noncovalent binding between graphene oxide (GO) sheets and uncharged porphyrin derivatives. The formation of the complexes is proved by studying the ground- and excited-state properties with the use of absorption, steady-state, and time-resolved fluorescence measurements. Despite the lack of charged groups in porphyrin, the complexes are stable and their binding is effective and occurs via two distinct interaction mechanisms. The results indicate that a fast deactivation process of emission is triggered, which is mainly static (and likely due to electron donor/acceptor action), even if small contribution of collisional (dynamic) quenching is present and depends on the GO sites that remained available after the complex formation. The obtained supramolecular structure also displays interesting prospects as the “turn-on” fluorescence sensor of cationic pollutants.
Placido G. Mineo, Fabiana Vento, Antonio Abbadessa, Emilio Scamporrino, and Angelo Nicosia
Elsevier BV
Abstract The measure of the acid concentration in an organic media is a common issue in chemistry. With the aim to overcome this problem in a facile and inexpensive way, the spectroscopic properties of a PEGylate porphyrin derivative, the 5,10,15,20-p-(ω-methoxypolyethyleneoxyphenyl) porphyrin (P), as an acidity sensor were tested. Its behaviour was analysed in toluene and several fuels through acid titration experiments. In each case, examining UV–vis and fluorescence spectroscopic data, the disappearance of the free-base porphyrin derivative Uv–vis signals (B- and Q-bands) and the increasing of new bands, as a consequence of the added acid, was monitored. On the basis of these data it was possible to evaluate the presence of acid in several organic media as toluene, gasoline, diesel, and jet fuel, using our porphyrin derivative in very low amount (about 3 ppm). Finally, in order to exclude the risk of a negative contribution of P in ash formation, the complete oxidation of the porphyrin compound under common engine's combustion conditions was also ascertained.
Maria Angela Castriciano, Paola Cardiano, Enza Fazio, Placido Giuseppe Mineo, Angelo Nicosia, Roberto Zagami, Mariachiara Trapani, Luigi Monsù Scolaro, and Sandra Lo Schiavo
American Chemical Society (ACS)
The potential of pyrene-1-sulfonate to act as an emitting anion for the development of ionic liquids is explored here. Amphiphilic trimethylpropylammonium hepta(isooctyl)octasilsesquioxane and conventional imidazolium, namely, 1-vinyl-3-hexyl-, 1-vinyl-3-decyl-, and 1-methyl-3-decyl-imidazolium, featuring moderate alkyl chain length substituents, have been chosen as countercations. The new species have been synthesized via simple metathesis reactions involving pyrene-1-sulfonate sodium salt and the appropriate halide cation precursors. Their thermal behavior has been investigated by thermogravimetric and differential scanning calorimetry at different scanning rates. According to this latter technique, only the trimethylpropylammonium hepta(isooctyl)octasilsesquioxane pyrenesulfonate adduct, displaying a reversible glass transition at −4.2 °C, may be classified as an ionic liquid. All pyrene-1-sulfonate imidazolium-based ion pairs are crystalline solids with the melting point just above 100 °C that produce very complex, nonreversible, and scanning rate-dependent thermograms, very likely arising from polymorphism phenomena. Such a behavior may be attributed to the pyrene-1-sulfonate polycyclic system, which in solution, as confirmed through spectroscopic characterization, displays a general attitude in promoting supramolecular structures via cation interactions. Emission lifetime measurements on the emitting fluorophore reveal that there are at least two different active species, whereas light scattering measurements show the presence of aggregates with hydrodynamic radii depending on the medium and adduct concentration. Tests aimed at investigating the potential of these novel pyrene-1-sulfonate salts in functionalization/exfoliation of graphite flakes are also reported here.
Angela Scala, Anna Piperno, Serena M. Torcasio, Angelo Nicosia, Placido G. Mineo, and Giovanni Grassi
Elsevier BV
Abstract An innovative solvent- and catalyst-free procedure for the grafting of acetylene groups on polylactic acid (PLA) backbone is reported, using propargylamine as alkyne donor. The synthetic protocol was tested at different PLA/propargylamine molar ratio and the efficiency was determined in terms of functionalization degree and molecular weights. The engineering of PLA by the green protocol introduces alkyne moieties and generates free hydroxyl groups that are exploited to increase the alkyne functionality by treatment with pent-4-ynoic anhydride. Alkyne-grafted PLA derivatives are useful building blocks for access to a variety of functionalized polymers by Cu(I)-catalyzed cycloaddition reaction (CuAAC) with azides derivatives. As a proof of principle, methoxypolyethylene glycol azide and azide-fluor 545 are selected as models of hydrophilic polymer and fluorescent probe, respectively.