In the context of sustainable materials for outdoor applications, the use of bio-based and biodegradable composites reinforced with agro-industrial waste represents a promising strategy. However, exposure to sunlight and oxygen can lead to photo-oxidation, potentially compromising both performance and biodegradability. In this study, Mater-Bi (MB) was compounded with 10 and 20 wt% grape pomace (GP), a by-product rich in polyphenols, and the resulting biocomposites were subjected to accelerated aging. The impact of photo-oxidation was evaluated through rheological, thermal, and mechanical analyses, alongside biodegradation tests in soil. The results revealed that while neat MB undergoes significant degradation upon aging, the GP-filled composites exhibited better resistance to photo-oxidative damage. Importantly, the biodegradation behaviour of the aged samples was also investigated, highlighting how prior oxidative degradation influences the subsequent disintegration of the material in a natural environment. The findings underscore the importance of assessing the end-of-life performance of biocomposites after environmental weathering, to ensure their sustainability under real-life outdoor conditions.

Biodegradable polymers often exhibit inferior properties and higher cost compared to their fossil-derived counterparts. The addition of plant waste and by-products can improve their performances, providing in the meantime functional activity and reducing their cost. In this work, we summarize the preparation of different biocomposites (BioCs) incorporating two diverse amounts (10 % and 20 %) of grape pomace (GP) in a Mater-Bi (MB) sample. GP, MB as well as BioCs were fully characterized. The influence of addition of GP on the properties and degradation in soil of the biocomposites was evaluated in comparison with the neat MB. However, natural antioxidants and other active compounds from GP could be sensitive to temperature. Thus, GP and MB underwent heat treatment at 180 degrees C to simulate and induce possible degradation during BioCs processing. GP analysis (particle size 50 mu m) showed only a slight decrease of antioxidant potency, despite the heat treatment simulating the BioCs processing. 1 H NMR of the MB soluble fraction in CDCl3 displayed the presence of two polymeric components: polylactide (PLA) and poly(butylene adipate-co-butylene terephthalate) (PBAT). Introduction of GP in the polymer matrix induced a proportional increase of antioxidant property in the BioCs as well as in complex viscosity at low frequencies. Moreover, a slight increase in the elastic modulus was observed with increasing the crystallinity of the samples. Degradation rate in soil, monitored by weight loss, increased with filler content and time. Moreover, NMR showed that, in the recovered sample after 45 days, the composition of PBAT changed, with the terephthalic percentage increased.

In this work, polylactide (PLA) was loaded with wood flour (WF) or hazelnut shells (HSs) (10% and 20% of fillers). The matrix and biocomposites were fully characterized from a mechanical and rheological point of view to test their processability and mechanical performance. Compost burial degradation test (30 days), with or without a prior photo-oxidation step, assessed their biodegradability after an outdoor application, and was monitored by weight loss (WL). The viscosity of the biocomposites was lower than that of the matrix and this unusual result can be attributed to a limited adhesion between the PLA and fillers. Both fillers increased the elastic modulus but decreased the tensile strength and elongation at break. As for the weathering, the degradation of PLA was mostly due to hydrolytic chain scission due to the presence of humidity. Resistance of PLA to UV irradiation improved in presence of both the two fillers. Their lignocellulosic nature was responsible for this behavior. Both fillers induced a high resistance and lower degradation in compost: WL percentages of virgin PLA was about 26%, biocomposites with 20% of WF or HS showed WL of about 10% and 14%, respectively. Photo-oxidation (36 h with condensation cycle) increased the compost degradation rate of both biocomposites and WL of PLA with 20% of WF or HS were about 15% and 21%, respectively, after 30 days.Highlights Poor adhesion between the matrix and fillers reduced the biocomposites viscosity. Fillers increased the elastic modulus but decreased the properties at break. Both fillers improved the resistance of PLA to UV irradiation. Biocomposites showed a lower susceptibility to compost degradation than PLA. Photo-oxidation increased the compost degradation rate of biocomposites. A biocomposites studying from the cradle to the grave. image

Biodegradable and potentially biobased polyesteramide oligomers (PEA-Pro), obtained from melt condensation of sebacic acid and 3-amino-1-propanol, were characterized by nuclear magnetic resonance (NMR), matrix assisted laser desorption/ionization-time of flight/time of flight-mass spectrometry/mass spectrometry (MALDI-TOF/TOF-MS/MS), thermogravimetric analysis (TGA), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). NMR analysis showed the presence of hydroxyl and amino terminal groups as well as carboxylic groups of the sebacate moiety. Hydroxyl and carboxyl termination had the same abundance, while the amine termination was 2.7-times less frequent. Information regarding the fragmentation pathways and ester/amide bond sequences was obtained by MALDI-TOF/TOF-MS/MS analysis performed on sodiated adducts of cyclic species and linear oligomers. Different end groups did not influence the observed fragmentation. Three fragmentation pathways were recognized. The β-hydrogen-transfer rearrangement, which leads to the selective scission of the –O–CH2– bonds, was the main mechanism. Abundant product ions originating from –CH2–CH2– (β–γ) bond cleavage in the sebacate moiety and less abundant ions formed by –O–CO– cleavages were also detected. TGA showed a major weight loss (74%) at 381 °C and a second degradation step (22% weight loss) at 447 °C. Py-GC/MS performed in the temperature range of 350–400 °C displayed partial similarity between the degradation products and the main fragments detected in the MALDI-TOF/TOF-MS/MS experiments. Degradation products derived from amide bonds were related to the formation of CN groups, in agreement with the literature.

Biodegradable polymers are used in many biomedical devices, such as implants, cellular scaffolds and drug delivery systems. To improve drug delivery capability and to reduce systemic toxicity, the interest in polymer-drug conjugates has increased remarkably. With this aim, pranoprofen (PPF) (an effective non-steroidal anti-inflammatory drug used mainly in ophthalmology) was conjugated to poly(epsilon-caprolactone) (PCL) via microwave-assisted transesterification, acid-catalyzed by p-toluenesulfonic acid. The products obtained were characterized by NMR, matrix assisted laser desorption ionization time of flight mass spectrometry, gel permeation chromatography (which gave proof of the covalent link between PPF and PCL) and thermal analyses. The conjugates were found to contain up to 4.3% w/w of PPF and had molecular weights ranging from 5 to 12 kDa. (c) 2020 Society of Industrial Chemistry

Osteoarthritis (OA) is a debilitating disease affecting joints and impairing the ability to perform everyday tasks. Current treatment regimens tend to provide little to no relief. Therefore, there is a huge need for alternative strategies to manage this painful condition. The delivery of anti-inflammatory drugs into an injured joint with the aim of eliminating articular inflammation and modulate cartilage damage could be a useful strategy to treat OA. Accordingly, the aim of this study is to prepare microparticles (MPs) from new biodegradable poly (3-hydroxybutyrate-co-ε-caprolactone) copolymers (PHBCL) for the potential intra-articular injection of Diclofenac sodium for OA treatment. MPs were prepared starting from copolymers having different molecular weights and an HB/CL molar ratio and studied for their morphologies and size distribution by scanning electron microscopy. Drug loading and encapsulation efficiency were also determined. The in vitro release profile was assessed by the dialysis bag technique and the kinetic profile was evaluated by using several mathematical models revealing a diffusion release mechanism. A1 polymer and related MPs, as representative of the group, were selected for further biological investigation. In vitro studies performed on CaCo-2 and Balb/3T3 cells showed no toxic effects at the desired concentrations as revealed by MTT, CFE and Comet assays.

In this study, we carried out the structural and thermal characterization of a medical-grade poly (lactide) (PLA) by SEC, TGA, DSC, NMR, ICP-MS and Py-GC/MS. Moreover, we investigated the laser-induced degradation occurring when ultrashort laser pulses (ULP) were employed to cut extremely thin polymer films prepared by solvent-casting. ULP polymer cutting technology is an interesting manufacturing process for its advantages in potential medical applications. In fact, heat transmission to the region surrounding the cuts is limited, so that the incisions are precise and the effects on the regions around them are small. In this way, the need for post-processing is reduced and ULP cutting becomes interesting for industrial applications. However, degradation induced by ULP may occur and compromise the properties of the polymer samples. To investigate this possibility, portions of PLA films, ultrashort laser cut (ULC) and uncut, were analysed by SEC, DSC, NMR and FTIR. Furthermore, PLA oligomers were studied by ESI-MS. Both SEC and NMR showed a decrease in the molecular weight. FTIR, ESI-MS and NMR spectra revealed the presence of olefin end groups originated from a β-H transfer mechanism, induced by heat and/or light (Norrish II mechanism). Additionally, the inspection of the ESI mass spectra highlighted the cleavage of ester bonds related to the Norrish I type mechanism, undetected by the other techniques.

A biodegradable poly(3-R-hydroxyalkanoate) synthesized by Pseudomonas mediterranea was investigated as a biomaterial to obtain colloidal drug delivery systems. Using a nanoprecipitation method, nanoparticles with a mean size of 155 nm and a negative surface charge were formed. They can be freeze-dried by adding hydroxypropyl-β-cyclodextrin as a cryoprotectant, and they have been shown to efficiently load both a hydrophilic (calcein) and a lipophilic (Nile red) model probe. Since this polymer contains terminal double bonds in the side chains, cross-linking conditions were tested. In particular, under the action of UV rays or irradiation with an incandescent yellow lamp, this polymer tended to cross-link.

ABSTRACTNew biodegradable biomaterials are attracting a huge interest as alternative to conventional polymers used in the field of drug delivery. In this work, we evaluated the ability of new biocompatible and biodegradable polyesters to form nanoparticles (NPs), and tested their potential carrier properties for controlled release of hydrophilic or lipophilic compounds. Multiblock copolymers derived from poly(R‐3‐hydroxybutyrate) and poly(1,4‐butylene adipate) by microwave‐assisted transesterification, having different chemical and physicochemical properties were tested. Nanoprecipitation was applied to obtain NPs with a homogenous size distribution. Oil Red O and calcein were encapsulated as lipophilic and hydrophilic probes, evaluating NP mean size and size polydispersity, surface charge, encapsulation efficiency, and release profile. The release curves were fitted into mathematical models to investigate the release mechanism. NPs stability appeared to be strictly related to storage conditions. The NPs were also successfully autoclaved and their mucoadhesive behavior was assessed by a “mucin‐particle method.” © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47233.

Pseudomonas aeruginosa ATCC 27853 was cultured on media containing long odd-chain fatty acids. Heptadecanoic, nonadecanoic, and heneicosanoic acids sustained cell growth and resulted in polyhydroxyalkanoate (PHA) accumulation when culturing was conducted under nitrogen starvation conditions. No PHA was produced using a complete or magnesium-deprived medium. The isolated polyesters were characterized by gas chromatography and liquid chromatography-electrospray ionization mass spectrometry (ESI-MS) of methanolyzed samples, 1H and 13C NMR spectroscopy, gel permeation chromatography, ESI MS of partially pyrolyzed samples, and differential scanning calorimetry. These PHAs are composed of seven different odd-chain repeating units starting from 3-hydroxyvalerate, with the highest species being the, to date, unreported constituent 3-hydroxyheptadecanoate, and minor amounts of 2 or 3 even-chain comonomers. The PHAs are soft, sticky, rubber-like materials having glass transition temperatures between -45 and -39°C, melting temperatures between 48 and 52°C, enthalpies of melting around 11J/g, and molar masses ranging from 77 to 188kg/mol. Statistical analysis of the ESI mass spectra of the products of their partial pyrolysis showed that they are pure copolymers and not a blend of copolymers or homopolymers.

Pseudomonas strains produce rhamnolipid mixtures (RLs) that generally consist of one or two molecules of rhamnose linked to one or two molecules of 3-hydroxyalkanoic acid. This study evaluates carbon source effects (glycerol, glucose, myristic acid, and Brassica carinata oil) on the synthesis of monorhamnolipids (mono-RLs) versus dirhamnolipids (di-RLs) in a human isolate of Pseudomonas aeruginosa PAL05. Spectrophotometry, an emulsifying index (E24) test, and an orcinol assay confirmed the production of RLs by PAL05. Purified RLs were characterized by 1H NMR analysis. PAL05 primarily produces mono-RLs when provided carbon sources containing long chain fatty acids (FAs) (myristic acid and B. carinata oil) and di-RLs when provided glycerol or glucose. qRT-PCR analysis showed that delayed expression of rhlC occurred when B. carinata oil was used, but not glycerol, glucose, or myristic acid. Our data show that the carbon source influenced the transcriptional expression of the rhlC gene and, consequently, the predominance of mono-RLs or di-RLs in PAL05 cultures.

RATIONALE:Bacterial poly(3-hydroxyalkanoates) (PHAs) are an emergent class of plastic materials available from renewable resources. Their properties are strictly correlated with the comonomeric composition and sequence, which may be determined by various mass spectrometry approaches. In this paper we compare fast-atom bombardment (FAB) and electrospray ionization (ESI) to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of partially pyrolyzed samples.METHODS:We determined the compositions and sequences of the medium-chain-length PHAs (mcl-PHAs) prepared by bacterial fermentation of Pseudomonas aeruginosa ATCC 27853 cultured in media containing fatty acids with 8, 12, 14, 18, and 20 carbon atoms as carbon sources by means of MALDI-TOFMS of pyrolyzates, and compared the results with those obtained by FAB- and ESI-MS in previous studies. MALDI matrices used were 9-aminoacridine (9-AA) and indoleacrylic acid (IAA).RESULTS:MALDI-TOFMS was carried out in negative ion mode when using 9-AA as a matrix, giving a semi-quantitative estimation of the 3-hydroxyacids constituting the PHAs, and in positive mode when using IAA, allowing us, through statistical analysis of the relative intensity of the oligomers generated by pyrolysis, to establish that the polymers obtained are true random copolyesters and not a mixture of homopolymers or copolymers.CONCLUSIONS:MALDI-TOFMS in 9-AA and IAA of partial pyrolyzates of mcl-PHAs represents a powerful method for the structural analysis of these materials. In comparison with FAB and ESI, MALDI provided an extended mass range with better sensitivity at higher mass and a faster method of analysis.

Within a research directed to developing new polymeric materials, suitable for decorating the surface of colloidal drug carriers, PEG(5000) polymers containing a free carboxyl or amine group at one end were conjugated to an alpha-lipoamino moiety (LAA). The conjugates were characterized by FT-IR,H-1-NMR, and MALDI-TOF mass spectrometry. They showed the same profile of solubility as the parent PEGs in water and in some polar and apolar solvents of pharmaceutical use. Representative terms showed to be well tolerated when incubated with Caco-2 or L929 cell cultures.Dedicated differential scanning calorimetry (DSC) studies were performed to prove the interaction of increasing molar fractions of the PEG(5000)-LAA conjugates with dipalmitoylphosphatidylcholine (DPPC) bilayers, to gain information about their possible incorporation in drug nanocarriers. While the parent PEGs affected only the superficial structure of bilayers, the amphiphilic PEG-LAA conjugates induced a perturbing effect on the thermotropic behavior of DPPC liposomes, according to the structure of the linked LAA residue. A molar concentration of these PEG-LAA between 5 and 10% was individuated as the most suitable to produce stable vesicles. (C) 2014 Elsevier B.V. All rights reserved.

Copolymers containing (R)-3-hydroxybutyric acid (HB), 1,4-butanediol (B), and adipic acid (A) were synthesized by microwave-assisted transesterification of biodegradable poly(R-3-hydroxybutyrate) (PHB) and poly(1,4-butyleneadipate) (PBA) in solution at different reaction times, composition of the starting mixture, and amount of 4-toluenesulfonic acid, used as a catalyst. The copolyesters were characterized with regard to their molecular weights, thermal properties, molar composition, and average block length of repeating units by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXS), 1H-NMR, and 13C-NMR, respectively. Random and microblock copolymers could be obtained depending on experimental conditions, with weight average molecular weight of up to 17,000. The glass transition temperature (Tg) of all samples lay in the range between the Tgs of PBA and PHB, while their structure varied from partially crystalline to totally amorphous. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectra of copolymers allowed us to ascertain that they were hydroxyl and carboxyl chain-end terminated.

Poly(ethylene glycol) (PEG2000) polymers containing one or two amine residues are linked to a-lipoamino acids (LAA) to produce mono- and homo-disubstituted PEGLAA conjugates as new materials for the surface coating of colloidal drug carriers. Conjugates are characterized by FT-IR, 1H-NMR, and MALDITOF mass spectrometry. Differential scanning calorimetry studies are performed to assess the interaction of PEG2000LAAs with a biomembrane model (dipalmitoylphosphatidylcholine multilamellar liposomes). Whereas the parent PEGs affect only the superficial structure of the bilayers, the amphiphilic PEGLAA conjugates exert a modulated perturbing effect on the thermotropic profile of liposomes. A molar concentration between 5% and 10% is individuated as the more suitable to produce stable vesicles.

A direct, rapid, and easy electrospray ionization mass spectrometry (ESI-MS) method to determine concentrations of sebacic acid (SA) and terephthalic acid (TA) residues in biodegradable copolymers was developed. Copolyester samples were synthesized from 1,4-butanediol and sebacic and terephthalic acids by melt polymerization. Extraction of monomers was performed in methanol. Their concentrations were determined by direct infusion ESI-MS, without chromatographic separation, using 1,12-dodecanedioic acid (DDA) as an internal standard. Calibration curves were obtained by plotting the ratio of the areas of the peaks relative to monomers and DDA standard as a function of their concentration ratio. We validated the method by determining the concentration of TA residue using both the ESI-MS protocol and high-performance liquid chromatography (HPLC) analysis with UV detection. The linearity range and the detection limit of this assay were 0.1-5.0 and 0.01 ppm for SA and 0.1-6.0 and 0.03 ppm for TA. This assay represents a useful alternative to conventional methods currently employed for acid quantification, resulting advantageous for its speed and high sensitivity.

Cepacian is an exopolysaccharide produced by the majority of the isolates belonging to the Burkholderia cepacia complex bacteria, a group of 17 species, some of which infect cystic fibrosis patients, sometime with fatal outcome. The repeating unit of cepacian consists of a backbone having a trisaccharidic repeating unit with three side chains, as reported in the formula below. The exopolysaccharide is also acetylated, carrying from one to three acetyl esters per repeating unit, depending on the strain examined. The consequences of O-acetyl substitution in a polysaccharide are important both for its biological functions and for industrial applications, including the preparation of conjugated vaccines, since O-acetyl groups are important immunogenic determinants. The location of acetyl groups was achieved by NMR spectroscopy and ESI mass spectrometry and revealed that these substituents are scattered in non-stoichiometric ratio on many sugar residues in different positions, a feature which adds to the already unique carbohydrate structure of the polysaccharide.

Linking PEG(2,000) polymers ending in 1 or 2 carboxylic groups to lipoamino acids (LAAs) gives mono- and homo-disubstituted PEG-LAA conjugates. They show an identical solubility to parent PEGs in water and organic solvents. By DSC the degree and depth of interaction of these conjugates with a biomembrane model is studied, gaining information about their future incorporation in drug-loaded nanocarriers. The ability of PEG-LAA conjugates to adopt an ordinate arrangement on the surface of particles and efficiently cover them is demonstrated, compared to DSPE-PEG, by measuring the zeta potential values of negatively charged liposomes prepared in their presence.