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Carboxymethylated derivatives of pullulan (PU) were synthesized and evaluated as coating for the postharvest preservation of blueberries. Carboxymethylpullulan was obtained by etherification reaction with the substitution degrees of 0.52, 0.34, and 0.26 for CMP1, CMP2, and CMP3 respectively. Infrared spectroscopy and nuclear magnetic resonance results showed characteristic signals of the carbonyl group belonging to the carboxymethyl group. Thermal analysis showed that CMP1, CMP2, and CMP3 derivatives presented thermal stability values of 209.91 C, 214.73 C, and 225.52 °C, respectively, and were lower with respect to PU with Td of 238.84 °C. Furthermore, an increase in the glass transition temperature due to carboxymethylation was determined. The chemical modification decreased the contact angle with respect to PU (71.34°) with values for CMP1, CMP2, and CMP3 of 39.89°, 53.72° and 60.61°, respectively. The carboxymethylation also increased the water vapor permeability and mechanical properties of the films. In addition, it was found that the CMP molecules affected the optical properties. The application of CMP-based coatings reduced the mass loss and ripening rate of blueberries compared to native pullulan, therefore, packaging from CMP molecules could be used as a coating capable of delaying ripening and extending the shelf life of fruits.

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Renewable materials of biological origin exhibit attractive properties in relation to traditional plastics, as they can be partially or completely replaced, thereby reducing environmental impacts. Hemicelluloses are a group of polysaccharides that have expanded applications when acetylated. Acetylation can improve the mechanical strength and water vapor barrier properties of xylan-based bioplastics. By partially acetylating xylan in the present study, it was possible to use water as a solvent for the film-forming solution and starch as a second polysaccharide in the formation of bioplastics. Xylan was modified via partial chemical acetylation by varying the reaction time, solvent, and catalyst content. The bioplastics were formed by non-acetylated xylan and acetylated xylan with degrees of substitution (DS) of 0.45 and 0.9, respectively, with starch to form blends using glycerol as a plasticizer. Acetylation with DS 0.45 showed better results in increasing the hydrophilicity of the bioplastic. On the other hand, acetylation influenced the thermal stability of bioplastics, increasing the maximum temperature of the degradation rate from 302 °C to 329 °C and 315 °C, owing to changes in the crystallinity of the polymers. In addition to the modulus of elasticity 2.99 to 290.61 and 274.67 MPa for the non-acetylated bioplastic and the bioplastic with DS of 0.45 and 0.90, respectively. Thus, the films obtained presented suitable physicochemical properties for use in various industrial applications, such as active and intelligent packaging in the food sector.

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Biotechnological advancements require the physicochemical alteration of molecules to enhance their biological efficacy for the effective treatment of gastric ulcers. The study aimed to produce a polyelectrolytic compound from red angico gum (AG) by carboxymethylation, evaluate its physicochemical characteristics and investigate gastric protection against ethanol-induced ulcers. AG and carboxymethylated angico gum (CAG) were characterized by Fourier transform infrared spectroscopy, determination of the degree of substitution and gel permeation chromatography (GPC) and 13C NMR techniques. The results demonstrated that the modification of the polymer was satisfactory, presenting conformational changes e improving the interaction with the gastric mucosa. AG and CAG reduced macroscopic and microscopic damage such as edema, hemorrhage and cell loss caused by exposure of the mucosa to alcohol. Both demonstrated antioxidant activity in vitro, and in vivo, pretreatment with gums led to the restoration of superoxide dismutase and glutathione levels compared to the injured group. Concurrently, the levels of malondialdehyde and nitrite decreased. Atomic force microscopy showed that CAG presented better conformational properties of affinity and protection with the gastric mucosa compared to AG in the acidic pH. Based on our findings, it is suggested that this compound holds promise as a prospective product for future biotechnological applications.

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In this study, pectins from commercial citrus and isolated from gabiroba (Campomanesia xanthocarpa) fruits, were obtained with different degrees of methyl-esterification (DM) and applied in the films. The DM ranged from 0 % to 62.5 % and the gradual de-esterification process was confirmed by mono-dimensional analysis (1H NMR). In order to investigate the influence of DM values in pectin film properties, PCP (DM: 62.5 %); PCP-5 (DM: 37.4 %); PCP-15 (DM: 19.1 %), and a fully de-esterified sample PCP-35 (DM: 0 %) were selected. The functional properties of the films clearly showed that the DM and cross-linking process are necessary to obtain a material with water resistance. Furthermore, pectin isolated from the fruits of gabiroba was purified (GW-Na, DM: 51.9 %) and partially de-esterified (GW-Na-5, DM: 37.1 %). These pectins were used, for the first time, in development of films and the physical and mechanical properties were compared with films made with PCP and PCP-5 samples. GW-Na and GW-Na-5 films presented suitable properties, with reduced solubility reduced (57.1 and 26.2 %), high degree of swelling (2.14 and 2.26), low flexibility (18.05 and 6.11 MPa), respectively. High strength and rigidity (99.36 and 1040.9 MPa), for both films (GW-Na and GW-Na-5) were demonstrated, similar to that obtained by analyzed citrus pectin.

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Ideally, the dressings used in the clinic have characteristics that help the wound closure process. Among several factors that affect the success of this healing process, there is debridement. It manages the wound bed components and the re-epithelialization process. Still, the property of debridement is not generally associated with dressings. Here, we show a chemically modified bacterial cellulose film conjugated to a proteolytic enzyme, papain, as a dressing with debridement properties. Bacterial cellulose films were reacted with a spacer derived from succinic acid and finally had this enzyme covalently immobilized in its structure by an amide bond. FT-IR and UV-vis showed bands typically of bioconjugated polymer. Enzymatic immobilization was very effective under the conditions applied with high yield (33% w/w), and these remained activated after the coupling reaction. The bacterial cellulose film with the enzyme papain attached to it was also very compatible with fibroblast cells, suggesting that it could be a promising wound dressing material for future research.

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In this work, polyhydroxybutyrate (PHB) was maleic anhydride (MA)-grafted in the molten state, using dicumyl peroxide (DCP) as a reaction initiator. Tin(II) 2-ethylhexanoate (Sn(Oct)2) and styrene monomer (St.) were used to maximize the maleic anhydride grafting degree. When PHB was modified with MA/DCP and MA/DCP/Sn(Oct)2, viscosity was reduced, suggesting chain scission in relation to pure PHB. However, when the styrene monomer was added, the viscosity increased due to multiple grafts of MA and styrene into the PHB chain. In addition, the FTIR showed the formation of a new band at 1780 cm-1 and 704 cm-1, suggesting a multiphase copolymer PHB-g-(St-co-MA). The PHB (MA/DCP) system showed a grafting degree of 0.23%; however, the value increased to 0.39% with incorporating Sn(Oct)2. The highest grafting efficiency was for the PHB (MA/DCP/St.) system with a value of 0.91%, while the PHB (MA/DCP/St./Sn(Oct)2) hybrid mixture was reduced to 0.73%. The chemical modification process of PHB with maleic anhydride increased the thermal stability by about 20 °C compared with pure PHB. The incorporation of 0.5 phr of the Sn(Oct)2 catalyst increased the efficiency of the grafting degree in the PHB. However, the St./Sn(Oct)2 hybrid mixture caused a deleterious effect on the maleic anhydride grafting degree.

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This study aimed to immobilize trypsin on activated carbon submitted to different surface modifications and its application in casein hydrolysis. With the aim of determining which support can promote better maintenance of the immobilized enzyme. Results showed that pH 5.0 was obtained as optimal for immobilization and pH 9.0 for the casein hydrolysis reaction for activated carbon and glutaraldehyde functionalized carbon. Among the supports used, activated carbon modified with iron ions in the presence of a chelating agent was the one that showed best results, under the conditions evaluated in this study. Presenting an immobilization yield of 95.15% and a hydrolytic activity of 4.11 U, same as soluble enzyme (3.76 U). This derivative kept its activity stable at temperatures above 40 °C for1 h and when stored for 30 days at 5 °C. Furthermore, it was effective for more than 6 reuse cycles (under the same conditions as the 1st cycle). In general, immobilization of trypsin on metallized activated carbon can be an alternative to biocatalysis, highlighting the advantages of protease immobilization.

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The objective of this work was to modify banana starch with pineapple leaf fibers (PALF) and its production of biodegradable films. The reaction conditions of the starch modification were a Starch/PALF mass ratio of 50, a time of 1 h and a temperature of 140 °C, to obtain a yield of 41.18 %. Characterization by FTIR and NMR confirmed that the chemical reaction was carried out. XRD and TGA analysis showed that the crystalline zones of the starch were affected during the modification and the product obtained is thermally less stable compared to unmodified starch. The modified starch showed a lower pasting profile compared to the native starch; however, the modified starch showed the ability to form a film. The starch-PALF films were obtained by the casting method and partially characterized. These films presented better mechanical properties compared to the unmodified films. Also, these films could compete with conventional non-biodegradable plastics.

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Hydrogels are structures that have value for application in the area of tissue engineering because they mimic the extracellular matrix. Naturally obtained polysaccharides, such as chitosan (CH) and cashew gum, are materials with the ability to form polymeric networks due to their physicochemical properties. This research aimed to develop a scaffold based on chitosan and phthalated cashew tree gum and test it as a support for the growth of human mesenchymal stem cells. In this study, phthalation in cashew gum (PCG) was performed by using a solvent-free route. PCG-CH scaffold was developed by polyelectrolyte complexation, and its ability to support adherent stem cell growth was evaluated. The scaffold showed a high swelling rate. The pore sizes of the scaffold were analyzed by scanning electron microscopy. Human dental pulp stem cells (hDPSCs) were isolated, expanded, and characterized for their potential to differentiate into mesenchymal lineages and for their immunophenotypic profile. Isolated mesenchymal stem cells presented fibroblastoid morphology, plastic adhesion capacity, and differentiation in osteogenic, adipogenic, and chondrogenic lineages. Mesenchymal stem cells were cultured in scaffolds to assess cell adhesion and growth. The cells seeded on the scaffold showed typical morphology, attachment, and adequate distribution inside the matrix pores. Thus, cells seeded in the scaffold may improve the osteoinductive and osteoconductive properties of these biomaterials.

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The present work explores the esterification reaction in the polysaccharide extracted from the seaweed Gracilaria birdiae and investigates its antioxidant potential. The reaction process was conducted with phthalic anhydride at different reaction times (10, 20 and 30 min), using a molar ratio of 1:2 (polymer: phthalic anhydride). Derivatives were characterized by FTIR, TGA, DSC and XRD. The biological properties of derivatives were investigated by assays of cytotoxicity and antioxidant activity (2,2-diphenyl-1-picrylhydroxyl - DPPH and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt - ABTS). The results obtained by FT-IR confirmed the chemical modification, there was a reduction related to the presence of carbonyl and hydroxyl groups when compared to the in nature polysaccharide spectrum. TGA analysis showed a change in the thermal behavior of the modified materials. X-ray diffraction, it was shown that the in nature polysaccharide appeared as an amorphous material, while the material obtained after the chemical modification process had increased crystallinity, due to the introduction of phthalate groups. For the biological assays, it was observed that the phthalate derivative was more selective than the unmodified material for the murine metastatic melanoma tumor cell line (B16F10), revealing a good antioxidant profile for DPPH and ABTS radicals.

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Nanotechnology is a crucial technology in recent years has resulted in new and creative applications of nanomedicine. Polymeric nanoparticles have increasing demands in pharmaceutical applications and require high reproducibility, homogeneity, and control over their properties. Work explores the use of cashew phthalate gum (PCG) as a particle-forming polymer. PCG exhibited a pH-sensitive behavior due to the of acid groups on its chains, and control drug release. We report the development of nanoparticles carrying benznidazole. Formulations were characterized by DLS, encapsulation efficiency, drug loading, FTIR, pH-responsive behavior, release, and in vitro kinetics. Interaction between polymer and drug was an evaluated by molecular dynamics. Morphology was observed by SEM, and in vitro cytotoxicity by MTT assay. Trypanocidal effect for epimastigote and trypomastigote forms was also evaluated. NPs responded to the slightly basic pH, triggering the release of BNZ. In acidic medium, they presented small size, spherical shape, and good stability. It was indicated NP with enhanced biological activity, reduced cytotoxicity, high anti T. cruzi performance, and pH-sensitive release. This work investigated properties related to the development and enhancement of nanoparticles. PCG has specific physicochemical properties that make it a promising alternative to drug delivery, however, there are still challenges to be overcome.

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In recent years, fluctuating global fossil fuel market prices and growing concern about environmental pollution have increased efforts to obtain novel value-added products from renewable agricultural biomass. To this end, a wide variety of triacylglycerols (edible and non-edible oils and fats) and their derivatives (free fatty acids or monoalkyl esters) stand out as promising feedstocks for the production of biolubricant base stocks, due to their biodegradability, excellent physicochemical properties, and sustainable nature. These raw materials can be transformed into biolubricants using chemical or biochemical (lipases) catalysts, with the enzymatic production of biolubricants using lipases as catalysts being recognized as an environmentally friendly approach. The present mini-review highlights recent advances in this field, published in the last three years. The different chemical modification processes used to develop a wide variety of industrial biolubricant base stocks are comprehensively reviewed, with exploration of future prospects for industrial production via the enzymatic route. This study contributes to the current state-of-the-art, identifying relevant research questions and providing important technical information for new applications of lipases in oleochemical manufacturing industries.

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The optimization of the parameters involved in lignin extraction is crucial for obtaining a lignin with specific structural features for its further valorization. The aim of this work was to develop an eco-friendly organosolv protocol for tuning the acetylation degree of coconut shell lignins (CSLs) by using MgCl2 and HCl as catalyst and co-catalyst, respectively. CSLs were obtained by mixing coconut shell powder with 90% v/v acetic acid combined to no catalyst, 2% v/v HCl and 2% w/v MgCl2 (1, 2 and 3 h) and 2% w/v MgCl2 combined to 0.1, 0.25 and 0.5% v/v HCl (2 h) at 110 °C. CSLs were characterized by FTIR, 1H NMR, GPC and TGA. The effects of the acetylation degree were evaluated on their antioxidant activity (DPPH assay) and UV-blocking capacity in sunscreen formulations. The results have shown that the use of HCl as co-catalyst increased the lignin yield (from 21.4 to 48.8%) and the acetylation degree (from 0.81 to 1.58 mmol g-1), which positively affected thermal (200 < Tonset < 226 °C), antioxidant (46.6 < IC50 < 67.5 µg mL-1) and UV-blocking capacities of CSLs. It can be concluded that the design of the organosolv process was capable of generating lignins with peculiar functionalities and properties through an eco-friendly protocol.

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This study describes the synthesis of a new bioadsorbent with zwitterionic characteristics and its successful application for removal of a cationic dye (crystal violet, CV) and an anionic dye (orange II, OII) from single component aqueous systems. The new bi-functionalized cellulose derivative (MC3) was produced by chemical modification of cellulose with succinic anhydride and choline chloride to introduce carboxylic and quaternary ammonium functional groups on the cellulose surface. MC3 was characterized by several wet chemical and spectroscopic methods. The effects of solution pH, contact time, and initial solute concentration on removal of CV and OII by MC3 were investigated. Studies of the desorption and re-adsorption of the dyes were also carried out. The isotherms for adsorption of CV and OII on MC3 were satisfactorily fitted using the Konda and Langmuir models. MC3 showed experimental maximum adsorption capacities of 2403 mg g-1 for CV and 201 mg g-1 for OII. The desorption and re-adsorption results showed that MC3 could be reused in successive adsorption cycles, which is essential for minimizing process costs and waste generation. The findings showed that MC3 is a versatile biosorbent capable of efficiently removing both cationic and anionic dyes.

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This work aimed to develop and evaluate the influence of processing variables on the morphology and swelling of sulfonated poly(ether ether ketone) (SPEEK) spheres for possible applications as a biomaterial. We used the drip method to obtain spheres with the polymer starting solutions SPEEK-6 (w/v: 6%) and SPEEK-10 (w/v: 10%), drip rates (20 and 30 mL/h), and drip heights (5 and 10 cm) in experimental planning. The samples were characterized by Fourier-transform infrared spectroscopy (FTIR), optical microscopy (OM), the absorption capacity of phosphate-buffered saline (PBS) by swelling (%), and statistical analysis of data through Design of Experiments (DOE). The obtained results evidenced that the processing variables influenced the morphology and swelling. Spheres with a bigger concentration of the polymer solution presented a greater degree of sulfonation (DS). We verified that the diameter of the spheres was directly related to the variable height and the sphericity was associated with the speed and viscosity of the solution. Bigger and more pores in a greater amount were observed in the spheres with a greater DS, influencing the behavior of the swelling in PBS. The better variable combinations with a high DS, regular sphericity, a smaller diameter, and greater swelling were the samples S2-10-20-5 e S10-10-20-5. The cytotoxicity indicated that the best samples obtained in the experimental planning (S2-10-20-5 and S10-10-20-5) were not toxic. In that regard, the evaluated spheres presented cell viability and swelling capacity, suggesting their possible applications as biomaterials.

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The linear anionic class of polysaccharides, glycosaminoglycans (GAGs), are critical throughout the animal kingdom for developmental processes and the maintenance of healthy tissues. They are also of interest as a means of influencing biochemical processes. One member of the GAG family, heparin, is exploited globally as a major anticoagulant pharmaceutical and there is a growing interest in the potential of other GAGs for diverse applications ranging from skin care to the treatment of neurodegenerative conditions, and from the treatment and prevention of microbial infection to biotechnology. To realize the potential of GAGs, however, it is necessary to develop effective tools that are able to exploit the chemical manipulations to which GAGs are susceptible. Here, the current knowledge concerning the chemical modification of GAGs, one of the principal approaches for the study of the structure-function relationships in these molecules, is reviewed. Some additional methods that were applied successfully to the analysis and/or processing of other carbohydrates, but which could be suitable in GAG chemistry, are also discussed.

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Liposomal systems are well known for playing an important role as drug carriers, presenting several therapeutic applications in different sectors, such as in drug delivery, diagnosis, and in many other academic areas. A novel class of this nanoparticle is the actively target liposome, which is constructed with the surface modified with appropriated molecules (or ligands) to actively bind a target molecule of certain cells, system, or tissue. There are many ways to functionalize these nanostructures, from non-covalent adsorption to covalent bond formation. In this review, we focus on the strategies of modifying liposomes by glycerophospholipid covalent chemical reaction. The approach used in this text summarizes the main reactions and strategies used in phospholipid modification that can be carried out by chemists and researchers from other areas. The knowledge of these methodologies is of great importance for planning new studies using this material and also for manipulating its properties.

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Cell-penetrating peptides (CPPs) comprise a class of short polypeptides that possess the ability to selectively interact with the cytoplasmic membrane of certain cell types, translocate across plasma membranes and accumulate in the cell cytoplasm, organelles (e.g., the nucleus and mitochondria) and other subcellular compartments. CPPs are either of natural origin or de novo designed and synthesized from segments and patches of larger proteins or designed by algorithms. With such intrinsic properties, along with membrane permeation, translocation and cellular uptake properties, CPPs can intracellularly convey diverse substances and nanomaterials, such as hydrophilic organic compounds and drugs, macromolecules (nucleic acids and proteins), nanoparticles (nanocrystals and polyplexes), metals and radionuclides, which can be covalently attached via CPP N- and C-terminals or through preparation of CPP complexes. A cumulative number of studies on animal toxins, primarily isolated from the venom of arthropods and snakes, have revealed the cell-penetrating activities of venom peptides and toxins, which can be harnessed for application in biomedicine and pharmaceutical biotechnology. In this review, I aimed to collate examples of peptides from animal venoms and toxic secretions that possess the ability to penetrate diverse types of cells. These venom CPPs have been chemically or structurally modified to enhance cell selectivity, bioavailability and a range of target applications. Herein, examples are listed and discussed, including cysteine-stabilized and linear, α-helical peptides, with cationic and amphipathic character, from the venom of insects (e.g., melittin, anoplin, mastoparans), arachnids (latarcin, lycosin, chlorotoxin, maurocalcine/imperatoxin homologs and wasabi receptor toxin), fish (pardaxins), amphibian (bombesin) and snakes (crotamine and cathelicidins).

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Chemical modification of polysaccharides is an important approach for their transformation into customized matrices that suit different applications. Microwave irradiation (MW) has been used to catalyze chemical reactions. This study developed a method of MW-initiated synthesis for the production of phthalated cashew gum (Phat-CG). The structural characteristics and physicochemical properties of the modified biopolymers were investigated by FTIR, GPC, 1H NMR, relaxometry, elemental analysis, thermal analysis, XRD, degree of substitution, and solubility. Phat-CG was used as a matrix for drug delivery systems using benznidazole (BNZ) as a model drug. BNZ is used in the pharmacotherapy of Chagas disease. The nanoparticles were characterized by size, PDI, zeta potential, AFM, and in vitro release. The nanoparticles had a size of 288.8 nm, PDI of 0.27, and zeta potential of -31.8 mV. The results showed that Phat-CG has interesting and promising properties as a new alternative for improving the treatment of Chagas disease.

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The objective of this research was to modify chicha gum with phthalic anhydride to obtain a new biologically active material. The chemical modification of the gum structure was proven through FTIR, elemental analysis, XRD, TG, and DSC. The derived materials demonstrated excellent inhibitory effect against P. aeruginosa and K. pneumoniae species (rating 100% inhibition) and could also inhibit Escherichia coli growth. The best antimicrobial activity observed for the derivatives suggests that chicha gum hydrophobization due to the addition of phthalic groups improved the interaction of these derivatives with bacterial cell wall components. On the other hand, the derivatives increased CC50 in macrophages but did not present acute toxicity or hemolytic activity, indicating that they are promising for use in prophylaxis or treatment of infections caused by Gram-negative bacteria.

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