Yerba Mate Extract in Microfibrillated Cellulose and Corn Starch Films as a Potential Wound Healing Bandage

Bibliometric study and potential applications in the development of starch films with nanocellulose: A perspective from 2019 to 2023

This study aimed to perform a bibliometric analysis of starch films with nanocellulose, using the Scopus database and VOSviewer and Bibliometrix software. A total of 258 documents were identified between 2019 and 2023, reflecting a growing interest in research, particularly in journals such as the International Journal of Biological Macromolecules, Polymers, and Carbohydrate Polymers. The most common terms were "starch" (349 occurrences), "cellulose" (207), and "tensile strength" (175). China (58 articles), Brazil (38), and India (33) led scientific production, with authors like Ilyas (13 articles) and Sapuan (10) at the forefront. Approximately 41.7 % of the studies used corn starch. The analysis revealed that 66 % of the studies investigated films with cellulose nanofibrils (CNF), 32 % with cellulose nanocrystals (CNC), and 2 % with bacterial nanocellulose (CB). The majority of studies (94.1 %) used the casting method for film production. Additionally, 35.44 % focused on reinforcing films with nanocellulose, while 7 % developed blends with other biopolymers. About 59.44 % examined the performance of starch films for food packaging, 11.25 % explored practical applications in various foods. Furthermore, 7.94 % incorporated active agents to improve antioxidant and antimicrobial properties, 1.30 % investigated active packaging. Moreover, 2.36 % explored the use of films in materials engineering, and 2.36 % explored biomedical potential. Only 0.40 % evaluated the impact of films on wastewater treatment. The analysis highlights the potential of starch films with nanocellulose, demonstrating their diverse applications and the growing interest in the field.

Isolation of taro peel cellulose nanofibers and its application in improving functional properties of taro starch nanocomposites films

The current work focuses on developing nanocomposite films using taro starch and cellulose nanofibers extracted from the root's peel. Films were prepared using mixtures of starch, cellulose nanofibers (0 %, 5 %, 10 %, and 15 % w/w), glycerol, and water. Results showed that the addition of cellulose nanofibers increased film thickness, opacity, UV-light barrier capacity, and water swelling percentage. All films showed a typical B-type X-ray diffraction pattern characteristic of semicrystalline materials. FTIR analysis confirmed chemical interactions between the starch chains and the nanofibers, which probably interact through hydrogen bonds. Nanocomposite films exhibited increased tensile strength and reduced strain at break compared to control materials. Films with cellulose nanofibers showed an increase in Young's modulus compared to control ones, with no differences observed between films with cellulose nanofibers at 10 % and 15 %. Furthermore, films with cellulose nanofibers at 5 % and 10 % exhibited lower water vapor permeability than control samples, while those with cellulose nanofibers at 15 % showed an increase in this parameter compared to other materials. These results suggest that incorporating taro cellulose nanofibers is a promising alternative for obtaining taro starch nanocomposites films with improved properties.

Impact of defibrillation technique on the rheological, thermo-mechanical, and nutritional properties of nanosuspensions produced from multiple fractions of pinhão seed (Araucaria angustifolia (Bertol.) Kuntze)

This work aimed to evaluate the influence of the mechanical defibrillation technique on the pinhão nanosuspensions production obtained from the whole pinhão, its coat, and almond. The nanosuspensions were characterized concerning their composition, morphology, thermal stability, rheological behavior, compound profiling, and cytotoxicity. The results revealed a significant fiber content in pinhão coat nanosuspension (63.12 ± 0.52 %) and non-fiber carbohydrates in whole pinhão (59.00 ± 0.13 %) and almond (74.39 ± 0.23 %) nanosuspensions. The defibrillation process led to micro/nano-sized fibers in pinhão coat nanosuspensions and small-size starch granules in almond nanosuspensions. The nanosuspensions containing pinhão coat exhibited a gel-like behavior, while almond nanosuspensions displayed liquid-like characteristics. Pinhão coat nanosuspensions presented a significant content of flavonoids and phytosterols, whereas almond-based nanosuspensions contained substantial sugar amounts. No cytotoxicity was observed at the concentrations evaluated. These findings demonstrated that the defibrillation technique impacted the properties of pinhão constituents, allowing their application in new product development.

FTIR, 1H, and 13C NMR Characterization and Antibacterial Activity of the Combination of Euphorbia Honey and Potato Starch

AIM AND OBJECTIVE

In recent years, natural biopolymer (potato starch) hydrogels have been widely used in the field of wound dressing material. This study aimed to develop and characterize a novel antibacterial hydrogel made from potato starch and natural honey.

METHODS

The structure of the composite films was evaluated by Fourier transform infrared (FTIR) and 1H,13C nuclear magnetic resonance (NMR) spectroscopy, and the antibacterial activities were tested by agar diffusion method. FTIR analysis showed chemical interaction between the components of Euphorbia honey (EH) and potato starch hydrogel (PSH).

RESULTS

The 1H-13C NMR and FTIR analyses of EH/PSH confirmed their structure and showed the presence of glucose and hydrocarbon derivatives. After 24 h of incubation, the EH/PSH hydrogel showed good antibacterial activity against three bacterial strains (K.pneumonia, P.mirabilis, and P. aeruginosa) by producing clear inhibition zones of 12.33 ± 1.88 mm, 15.33 ± 0.94, and 10 ± 0 mm, respectively. In addition, K. pneumonia, P. mirabilis, and P. aeruginosa were sensitive to the EH/SPH with a minimum inhibitory concentration (MIC) of 1 %.

CONCLUSION

These results suggest that EH-PS has potential as an alternative candidate to conventional antibiotics.

Nanofibrillated cellulose originated from Rhododendron ponticum to produce scaffolds using 3D printing for biomedical applications

Rhododendron ponticum is an invasive species that spreads rapidly and is described as one of the biggest threats to peatlands in Ireland. This study offers an innovative approach to utilizing Rhododendron waste. Initially, sawdust was submitted to a bleaching treatment and the nanofibrillated cellulose (NFC) was obtained using two different methods: ultra-fine friction grinding and twin-screw extrusion with the assistance of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) pre-treatment. The samples processed through twin-screw extrusion exhibited the presence of NFC at five intervals, as confirmed by TEM analysis. However, these samples displayed a higher diameter deviation compared to those processed through grinding alone. Notably, after 20 extrusion steps, the NFC diameter became more uniform, reaching approximately 35 nm. Sedimentation tests showed that extrusion produced more homogeneous cellulose size than the grinder method. However, FTIR characterization for the samples showed a unique band related to C-O-C glycosidic linkage. The results showed that grinding breaks these groups resulting in crystallinity values lower than extrusion, 50 % compared 60 %. Therefore, NFC with 20 steps by grinding was blended with polycaprolactone to produce a 3D scaffold using a 3D printer at different ratios of 1-5 % addition. The effect of 1 % of NFC was unique showing significant enhanced mechanical properties compared to pure polycaprolactone (PCL), additionally, the NFC does not exhibit toxicity so these materials show promise for biomedical applications.

Preparation, characteristics, and soil-biodegradable analysis of corn starch/nanofibrillated cellulose (CS/NFC) and corn starch/nanofibrillated lignocellulose (CS/NFLC) films

The objective of this study was to produce high-performance and biodegradable starch nanocomposites through film casting by using corn starch/nanofibrillated cellulose (CS/NFC) and corn starch/nanofibrillated lignocellulose (CS/NFLC). NFC and NFLC were obtained by super grinding process and added to fibrogenic solutions (1, 3, and 5 g/100 g of starch). The addition of NFC and NFLC from 1 to 5 % was verified to be influential in enhancing mechanical properties (tensile, burst, and tear index) and reducing WVTR, air permeability, and essential properties in food packaging materials. But, in comparison to control samples, the addition of NFC and NFLC from 1 to 5 % decreased the opacity, transparency, and tear index of films. In acidic solutions, produced films were more soluble than in alkaline or water solutions. The soil-biodegradability analysis showed that after 30 days of exposure to soil, the control film lost 79.5 % of its weight. The weight loss of all films was >81 % after 40 days. The results of this study may contribute to expanding the industrial applications of both NFC and NFLC by laying a basis for preparing high-performance CS/NFC or CS/NFLC.

Plant Polysaccharides in Engineered Pharmaceutical Gels

Hydrogels are a great ally in the pharmaceutical and biomedical areas. They have a three-dimensional polymeric structure that allows the swelling of aqueous fluids, acting as an absorbent, or encapsulating bioactive agents for controlled drug release. Interestingly, plants are a source of biogels, specifically polysaccharides, composed of sugar monomers. The crosslinking of these polymeric chains forms an architecture similar to the extracellular matrix, enhancing the biocompatibility of such materials. Moreover, the rich hydroxyl monomers promote a hydrophilic behavior for these plant-derived polysaccharide gels, enabling their biodegradability and antimicrobial effects. From an economic point of view, such biogels help the circular economy, as a green material can be obtained with a low cost of production. As regards the bio aspect, it is astonishingly attractive since the raw materials (polysaccharides from plants-cellulose, hemicelluloses, lignin, inulin, pectin, starch, guar, and cashew gums, etc.) might be produced sustainably. Such properties make viable the applications of these biogels in contact with the human body, especially incorporating drugs for controlled release. In this context, this review describes some sources of plant-derived polysaccharide gels, their biological function, main methods for extraction, remarkable applications, and properties in the health field.

Characterization of Gels and Films Produced from Pinhão Seed Coat Nanocellulose as a Potential Use for Wound Healing Dressings and Screening of Its Compounds towards Antitumour Effects

The reuse of agro-industrial waste assumes great importance today. Pinhão is the seed of Araucaria angustifolia, which is native to the mountains of southern Brazil, Paraguay, and Argentina. The coat is a by-product of this seed and is rich in phenolic compounds. The present study aimed to use the residue as a precursor material for the production of nanocellulose through the mechanical defibrillation process and perform the characterization of the films and the gel to investigate the effect on the physical and regenerative properties when incorporated with polyvinyl alcohol (PVA). The modulus of elasticity was higher when the MFC of pinhão was added to the PVA. Film and gel had their cytotoxicity tested by MTT assay using 3T3 fibroblast and Schwann cancer cells, and a migration assay was also performed using the scratch test on HaCat keratinocyte cells. For the scratch test, film and gel samples with low concentration presented a complete scratch closure in 72 h. Molecular docking was performed and quercetin had the ideal interaction score values, so it was used with the PACAP protein which presented a slightly moderate interaction with the protein synthesis of Schwann cells, presenting compactness of the compound after 14 ns.

Starch as a Matrix for Incorporation and Release of Bioactive Compounds: Fundamentals and Applications

Due to its abundance in nature and low cost, starch is one of the most relevant raw materials for replacing synthetic polymers in a number of applications. It is generally regarded as non-toxic, biocompatible, and biodegradable and, therefore, a safe option for biomedical, food, and packaging applications. In this review, we focused on studies that report the use of starch as a matrix for stabilization, incorporation, or release of bioactive compounds, and explore a wide range of applications of starch-based materials. One of the key application areas for bioactive compounds incorporated in starch matrices is the pharmaceutical industry, especially in orally disintegrating films. The packaging industry has also shown great interest in using starch films, especially those with antioxidant activity. Regarding food technology, starch can be used as a stabilizer in nanoemulsions, thus allowing the incorporation of bioactive compounds in a variety of food types. Starch also presents potential in the cosmetic industry as a delivery system. However, there are still several types of industry that could benefit from the incorporation of starch matrices with bioactive compounds, which are described in this review. In addition, the use of microbial bioactive compounds in starch matrices represents an almost unexplored field still to be investigated.

Nanocellulose for peripheral nerve regeneration in rabbits using citric acid as crosslinker with chitosan and freeze/thawed PVA

This work investigates peripheral nerve regeneration using membranes consisting of pure chitosan (CHI), which was further blended with nanofibrillated cellulose, with citric acid as crosslinker, with posterior addition of polyvinyl alcohol, with subsequent freeze thawing. Nanocellulose improves the mechanical and thermal resistance, as well as flexibility of the film, which is ideal for the surgical procedure. The hydrogel presented a slow rate of swelling, which is adequate for cell and drug delivery. A series ofin vitrotests revealed to be non-toxic for neuronal Schwann cell from the peripheral nervous system of Rattus norvegicus, while there was a slight increase in toxicity if crosslink is performed-freeze-thaw. Thein vivoresults, using rabbits with a 5 mm gap nerve defect, revealed that even though pure CHI was able to regenerate the nerve, it did not present functional recovery with only the deep pain attribute being regenerated. When autologous implant was used jointly with the biomaterial membrane, as a covering agent, it revealed a functional recovery within 15 d when cellulose and the hydrogel were introduced, which was attributed to the film charge interaction that may help influence the neuronal axons growth into correct locations. Thus, indicating that this system presents ideal regeneration as nerve conduits.

Microfibrillated cellulose films containing chitosan and tannic acid for wound healing applications

The effectiveness of tannic acid as antimicrobial and wound healing for burns have been shown for a century; however, uncontrolled target dosage may result in undesirable side-effects. Remarkably, tannic acid polyphenols compounds crosslinked with polymeric materials produce a strong composite containing the beneficial properties of this tannin. However, investigation of the crosslink structure and its antibacterial and regenerative properties are still unknown when using nanocellulose by mechanical defibrillation; additionally, due to the potential crosslink structure with chitosan, its structure can be complex. Therefore, this work uses bleach kraft nanocellulose in order to investigate the effect on the physical and regenerative properties when incorporated with chitosan and tannic acid. This film results in increased rigidity with a lamellar structure when incorporated with tannic acid due to its strong hydrogen bonding. The release of tannic acid varied depending on the structure it was synthesised with, whereas with chitosan it presented good release model compared to pure cellulose. In addition, exhibiting similar thermal stability as pure cellulose films with antibacterial properties tested against S. aureus and E. coli with good metabolic cellular viability while also inhibiting NF-κB activity, a characteristic of tannic acid.