Chitin Nanofibrils in Poly(Lactic Acid) (PLA) Nanocomposites: Dispersion and Thermo-Mechanical Properties

Preparation of nanochitin using deep eutectic solvents

Chitin is an abundant and renewable non-wood biopolymer. Nanochitin is formed by the assembly of chitin molecules, which has the advantages of large tensile strength, high specific surface area, and biodegradability, so it has been widely used. However, the traditional methods of preparing nanochitin have many drawbacks. As the new generation of green solvents, deep eutectic solvents (DESs) have been successfully applied in the fields of chitin dissolution, extraction, and nanochitin preparation. In this review, the relevant knowledge of chitin, nanochitin, and DESs was first introduced. Then, the application status of DESs in the fields of chitin was summarized, with a focus on the preparation of nanochitin using DESs. In conclusion, this review provided a comprehensive analysis of the published literature and proposed insights and development trends in the field of preparation of nanochitin using DESs, aiming to provide guidance and assistance for future researchers.

From Food Waste to Functional Biopolymers: Characterization of Chitin and Chitosan Produced from Prepupae of Black Soldier Fly Reared with Different Food Waste-Based Diets

The use of food waste as a rearing substrate to grow insects is an ecofriendly and sustainable alternative to food waste disposal. In the present research, Hermetia illucens prepupae were reared with a standard diet, different food waste-based diets based on vegetables, fruits, and meat, and a mixed one, where the previous three components were present equally. The demineralization and deproteination of the prepupae allowed for the obtainment of chitin that was then deacetylated to produce chitosan. Also, the bleaching of chitosan was attempted for further purification. The yield of the different reactions was investigated, and the infrared spectra of the obtained materials were analyzed to obtain information on the quantity and acetylation degree trend of the chitin and chitosan as a function of the diet. The possibility to slightly modulate the yield and acetylation degree of both biopolymers thanks to the specific diet was enlightened. Interestingly, the standard diet resulted in the highest fraction of chitin having the highest acetylation degree, and in the highest fraction of chitosan having the lowest acetylation degree.

The Effects of the Deacetylation of Chitin Nanowhiskers on the Performance of PCL/PLA Bio-Nanocomposites

The multiple roles of organic nanofillers in biodegradable nanocomposites (NC) with a blend-based matrix is not yet fully understood. This work highlights combination of reinforcing and structure-directing effects of chitin nanowhiskers (CNW) with different degrees of deacetylation (DA), i.e., content of primary or secondary amines on their surface, in the nanocomposite with the PCL/PLA 1:1 matrix. Of importance is the fact that aminolysis with CNW leading to chain scission of both polyesters, especially of PLA, is practically independent of DA. DA also does not influence thermal stability. At the same time, the more marked chain scission/CNW grafting for PLA in comparison to PCL, causing changes in rheological parameters of components and related structural alterations, has crucial effects on mechanical properties in systems with a bicontinuous structure. Favourable combinations of multiple effects of CNW leads to enhanced mechanical performance at low 1% content only, whereas negative effects of structural changes, particularly of changed continuity, may eliminate the reinforcing effects of CNW at higher contents. The explanation of both synergistic and antagonistic effects of structures formed is based on the correspondence of experimental results with respective basic model calculations.

Chitin nanofibrils modulate mechanical response in tympanic membrane replacements

The tympanic membrane (TM), is a thin tissue lying at the intersection of the outer and the middle ear. TM perforations caused by traumas and infections often result in a conductive hearing loss. Tissue engineering has emerged as a promising approach for reconstructing the damaged TM by replicating the native material characteristics. In this regard, chitin nanofibrils (CN), a polysaccharide-derived nanomaterial, is known to exhibit excellent biocompatibility, immunomodulation and antimicrobial activity, thereby imparting essential qualities for an optimal TM regeneration. This work investigates the application of CN as a nanofiller for poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymer to manufacture clinically suitable TM scaffolds using electrospinning and fused deposition modelling. The inclusion of CN within the PEOT/PBT matrix showed a three-fold reduction in the corresponding electrospun fiber diameters and demonstrated a significant improvement in the mechanical properties required for TM repair. Furthermore, in vitro biodegradation assay highlighted a favorable influence of CN in accelerating the scaffold degradation over a period of one year. Finally, the oto- and cytocompatibility response of the nanocomposite substrates corroborated their biological relevance for the reconstruction of perforated eardrums.

Comparison of the Degree of Acetylation of Chitin Nanocrystals Measured by Various Analysis Methods

Chitin and its derivate chitosan have versatile properties and have been used in various applications. One key parameter determining the functionality of chitin-based materials is the degree of acetylation (DA). For DA determination, NMR and FTIR spectroscopy are often considered to be the gold standard, but these techniques may not always be available and are rather time-consuming and costly. The first derivative UV method has been suggested, although accurate measurements can be challenging for materials with high degrees of acetylation, due to hydroxymethylfurfural (HMF) formation and other side reactions occurring. In this paper, we re-evaluated the first derivate UV method for chitin and chitosan powder, chitin nanocrystals, and deacetylated chitin nanocrystals. Our results showed that the first derivative UV method is capable of measuring DA with high accuracy (>0.9), leading to values comparable to those obtained by 1H NMR, 13C NMR, and FTIR. Moreover, by-product formation could either be suppressed by selecting the proper experimental conditions, or be compensated. For chitin nanocrystals, DA calculation deviations up to 20% due to by-product formation can be avoided with the correction that we propose. We conclude that the first derivative UV method is an accessible method for DA quantification, provided that sample solubility is warranted.

Polylactide (PLA) as a Cell Carrier in Mesophilic Anaerobic Digestion-A New Strategy in the Management of PLA

The management of waste polylactide (PLA) in various solutions of thermophilic anaerobic digestion (AD) is problematic and often uneconomical. This paper proposes a different approach to the use of PLA in mesophilic AD, used more commonly on the industrial scale, which consists of assigning the function of a microbial carrier to the biopolymer. The study involved the testing of waste wafers and waste wafers and cheese in a co-substrate system, combined with digested sewage sludge. The experiment was conducted on a laboratory scale, in a batch bioreactor mode. They were used as test samples and as samples with the addition of a carrier: WF-control and WFC-control; WF + PLA and WFC + PLA. The main objective of the study was to verify the impact of PLA in the granular (PLAG) and powder (PLAP) forms on the stability and efficiency of the process. The results of the analysis of physicochemical properties of the carriers, including the critical thermal analysis by differential scanning calorimetry (DSC), as well as the amount of cellular biomass of Bacillus amyloliquefaciens obtained in a culture with the addition of the tested PLAG and PLAP, confirmed that PLA can be an effective cell carrier in mesophilic AD. The addition of PLAG produced better results for bacterial proliferation than the addition of powdered PLA. The highest level of dehydrogenase activity was maintained in the WFC + PLAG system. An increase in the volume of the methane produced for the samples digested with the PLA granules carrier was registered in the study. It went up by c.a. 26% for WF, from 356.11 m³ Mg^-1 VS (WF-control) to 448.84 m³ Mg^-1 VS (WF + PLAG), and for WFC, from 413.46 m³ Mg^-1 VS, (WFC-control) to 519.98 m³ Mg^-1 VS (WFC + PLAG).

Chitin Nanocomposite Based on Plasticized Poly(lactic acid)/Poly(3-hydroxybutyrate) (PLA/PHB) Blends as Fully Biodegradable Packaging Materials

Fully bio-based poly(lactic acid) (PLA) and poly(3-hydroxybutyrate) (PHB) blends plasticized with tributyrin (TB), and their nanocomposite based on chitin nanoparticles (ChNPs) was developed using melt mixing followed by a compression molding process. The combination of PHB and ChNPs had an impact on the crystallinity of the plasticized PLA matrix, thus improving its oxygen and carbon dioxide barrier properties as well as displaying a UV light-blocking effect. The addition of 2 wt% of ChNP induced an improvement on the initial thermal degradation temperature and the overall migration behavior of blends, which had been compromised by the presence of TB. All processed materials were fully disintegrated under composting conditions, suggesting their potential application as fully biodegradable packaging materials.

Chitin Nanocrystals Provide Antioxidant Activity to Polylactic Acid Films

About 1/3rd of produced food goes to waste, and amongst others, advanced packaging concepts need to be developed to prevent this from happening. Here, we target the antioxidative functionality of food packaging to thus address food oxidation without the need for the addition of antioxidants to the food product, which is not desirable from a consumer point of view. Chitin nanocrystals (ChNC) have been shown to be promising bio-fillers for improving the mechanical strength of biodegradable plastics, but their potential as active components in plastic films is rather unexplored. In the current study, we investigate the antioxidant activity of chitin nanocrystals as such and as part of polylactic acid (PLA) films. This investigation was conducted using DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. Chitin nanocrystals produced via acid hydrolysis showed five times higher activity compared to crude chitin powder. When using these crystals as part of a polylactic acid film (either inside or on top), in both scenarios, antioxidant activity was found, but the effect was considerably greater when the particles were at the surface of the film. This is an important proof of the principle that it is possible to create biodegradable plastics with additional functionality through the addition of ChNC.

Viscoelastic and Properties of Amphiphilic Chitin in Plasticised Polylactic Acid/Starch Biocomposite

The enhancement of the PLA thermomechanical properties is significant due to its suitability as a replacement for primary synthetic polymer use in diverse industrial production. The amphiphilic chitin was used as a compatibilizer in PLA/starch biocomposite. The properties of plasticised polylactic acid blended with starch, and amphiphilic chitin was studied for enhanced thermomechanical and viscoelastic properties. Chitin was modified using acetylated substitution reaction and blended with plasticised PLA/starch biocomposite. The biocomposite was prepared with combined compression and melt extrusion techniques. The biocomposite’s thermomechanical, thermal, mechanical, and morphological properties were studied using dynamic mechanical analysis, TGA-DSC, tensile test, and scanning electron microscopy. The storage and loss modulus were significantly enhanced with increased amphiphilic chitin content. Similarly, the single peak of tan delta showed good miscibility of the polymeric blend. Additionally, the modulus increases with frequency change from 1 Hz to 10 Hz. The thermal stability of the biocomposite was observed to be lower than the neat PLA. The tensile properties of the biocomposite increased significantly more than the neat PLA, with P4S4C having the highest tensile strength and modulus of 87 MPa and 7600 MPa. The SEM images show good miscibility with no significant void in the fractured surface. The viscoelastic properties of PLA were enhanced considerably with plasticizer and amphiphilic chitin with improved biodegradability. The properties of the biocomposite can be adapted for various industrial applications.

Functional miscibility and thermomechanical properties enhancement of substituted phthalic acetylated modified chitin filler in biopolymer composite

The miscibility between hydrophobic and hydrophilic biopolymers has been of significant challenge. This study used a novel simplified chitin modification method to produce phthalic chitin using phthalic anhydride in a substitution reaction. The FT-IR functional group analysis was used to confirm the substitution reaction. The modified chitin was used as compatibilizer in polylactic acid (PLA)/starch biocomposite to enhance its properties. The biocomposite was prepared using melt extrusion and compression moulding technique. The biocomposite's morphological, thermomechanical and water absorption properties were characterized using scanning electron microscope, tensile test, dynamic mechanical analysis, thermogravimetry analysis, differential scanning calorimetry, thickness swelling and water absorption test. The FT-IR study shows a successful substitution reaction of the amine hydrogen ion present in the chitin as opposed to substituting the hydrogen ion in the hydroxide group. The tensile and impact properties of biocomposite incorporated with modified chitin showed better results compared with other samples. The SEM images showed uniform miscibility of the modified biocomposite. The dynamic mechanical analysis showed improved modulus value with the incorporation of modified chitin. The thermal properties showed improved thermal stability of the modified biocomposite. Furthermore, the percentage of water absorbed by biocomposite with modified chitin is reduced compared with the PLA/starch biocomposite. The produced biodegradable ternary blend can be used as a substitute for plastics in industrial applications.

Chitin Nanofibril-Nanolignin Complexes as Carriers of Functional Molecules for Skin Contact Applications

Chitin nanofibrils (CN) and nanolignin (NL) were used to embed active molecules, such as vitamin E, sodium ascorbyl phosphate, lutein, nicotinamide and glycyrrhetinic acid (derived from licorice), in the design of antimicrobial, anti-inflammatory and antioxidant nanostructured chitin nanofibrils–nanolignin (CN-NL) complexes for skin contact products, thus forming CN-NL/M complexes, where M indicates the embedded functional molecule. Nano-silver was also embedded in CN-NL complexes or on chitin nanofibrils to exploit its well-known antimicrobial activity. A powdery product suitable for application was finally obtained by spray-drying the complexes co-formulated with poly(ethylene glycol). The structure and morphology of the complexes was studied using infrared spectroscopy and field emission scanning electron microscopy, while their thermal stability was investigated via thermo-gravimetry. The latter provided criteria for evaluating the suitability of the obtained complexes for subsequent demanding industrial processing, such as, for instance, incorporation into bio-based thermoplastic polymers through conventional melt extrusion. In vitro tests were carried out at different concentrations to assess skin compatibility. The obtained results provided a physical–chemical, morphological and cytocompatibility knowledge platform for the correct selection and further development of such nanomaterials, allowing them to be applied in different products. In particular, chitin nanofibrils and the CN-NL complex containing glycyrrhetinic acid can combine excellent thermal stability and skin compatibility to provide a nanostructured system potentially suitable for industrial applications.

Influence of Chitin Nanocrystals on the Crystallinity and Mechanical Properties of Poly(hydroxybutyrate) Biopolymer

This study focuses on the use of pilot-scale produced polyhydroxy butyrate (PHB) biopolymer and chitin nanocrystals (ChNCs) in two different concentrated (1 and 5 wt.%) nanocomposites. The nanocomposites were compounded using a twin-screw extruder and calendered into sheets. The crystallization was studied using polarized optical microscopy and differential scanning calorimetry, the thermal properties were studied using thermogravimetric analysis, the viscosity was studied using a shear rheometer, the mechanical properties were studied using conventional tensile testing, and the morphology of the prepared material was studied using optical microscopy and scanning electron microscopy. The results showed that the addition of ChNCs significantly affected the crystallization of PHB, resulting in slower crystallization, lower overall crystallinity, and smaller crystal size. Furthermore, the addition of ChNCs resulted in increased viscosity in the final formulations. The calendering process resulted in slightly aligned sheets and the nanocomposites with 5 wt.% ChNCs evaluated along the machine direction showed the highest mechanical properties, the strength increased from 24 to 33 MPa, while the transversal direction with lower initial strength at 14 MPa was improved to 21 MPa.

Applications of chitin and chitosan based biomaterials for the adsorptive removal of textile dyes from water - A comprehensive review

The presence of pollutants in the water bodies deteriorate the water quality and make it unfit for use. From an environmental perspective, it is essential to develop new technologies for the wastewater treatment and recycling of dye contaminated water. The surface modified chitin and chitosan biopolymeric composites based adsorbents, have an important role in the toxic organic dyes from removal wastewater. The surface modification of biopolymers with various organics and inorganics produces more active sites at the surface of the adsorbent, which enhances dye and adsorbent interaction more reliable. Herein, the work brought in the thought of the application of various chitin and chitosan composites in wastewater remediation and suggested the versatility in composites for the development of rapid, selective and effective removal processes for the detoxification of a variety of organic dyes. It further emphasizes the existing obstruction and impending prediction for the deprivation of dyes via adsorption techniques.

Insight into melting point depression of polylactide nanocomposites with acetylated chitin nanocrystals

Chitin nanocrystal (ChNC) was used to prepare fully biodegradable nanocomposites with polylactide (PLA). The nucleation and melting behavior of nanocomposites were studied with the objective to correlate PLA-ChNC affinity to PLA crystallization. The results disclose that the PLA nanocomposites with pristine ChNCs and the ones with acetylated ChNCs show completely different nucleation and melting behavior because the role of ChNCs is altered after acetylation. Pristine ChNC acts as inert filler, with weak nucleating activity, while acetylated ChNCs as anti-nucleation agent, restraining crystallization of PLA. Accordingly, the nanocomposites with acetylated ChNCs show melting point depression, with reduced nucleation capability. The recrystallization and self-nucleation, as well as the double-melting behaviors were then studied in terms of acetylation levels of ChNCs and annealing temperatures, in order to better understand the relations between two-phase affinity and PLA chain dynamics. This work provides interesting information around designing thermal properties of the ChNC-filled PLA nanocomposites.

Liquid and Solid Functional Bio-Based Coatings

The development of new bio-based coating materials to be applied on cellulosic and plastic based substrates, with improved performances compared to currently available products and at the same time with improved sustainable end of life options, is a challenge of our times. Enabling cellulose or bioplastics with proper functional coatings, based on biopolymer and functional materials deriving from agro-food waste streams, will improve their performance, allowing them to effectively replace fossil products in the personal care, tableware and food packaging sectors. To achieve these challenging objectives some molecules can be used in wet or solid coating formulations, e.g., cutin as a hydrophobic water- and grease-repellent coating, polysaccharides such as chitosan-chitin as an antimicrobial coating, and proteins as a gas barrier. This review collects the available knowledge on functional coatings with a focus on the raw materials used and methods of dispersion/application. It considers, in addition, the correlation with the desired final properties of the applied coatings, thus discussing their potential.

Chitin Nanofibril Application in Tympanic Membrane Scaffolds to Modulate Inflammatory and Immune Response

Chitin nanofibrils (CNs) are an emerging bio-based nanomaterial. Due to nanometric size and high crystallinity, CNs lose the allergenic features of chitin and interestingly acquire anti-inflammatory activity. Here we investigate the possible advantageous use of CNs in tympanic membrane (TM) scaffolds, as they are usually implanted inside highly inflamed tissue environment due to underlying infectious pathologies. In this study, the applications of CNs in TM scaffolds were twofold. A nanocomposite was used, consisting of poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymer loaded with CN/polyethylene glycol (PEG) pre-composite at 50/50 (w/w %) weight ratio, and electrospun into fiber scaffolds, which were coated by CNs from crustacean or fungal sources via electrospray. The degradation behavior of the scaffolds was investigated during 4 months at 37 °C in an otitis-simulating fluid. In vitro tests were performed using cell types to mimic the eardrum, i.e., human mesenchymal stem cells (hMSCs) for connective, and human dermal keratinocytes (HaCaT cells) for epithelial tissues. HMSCs were able to colonize the scaffolds and produce collagen type I. The inflammatory response of HaCaT cells in contact with the CN-coated scaffolds was investigated, revealing a marked downregulation of the pro-inflammatory cytokines. CN-coated PEOT/PBT/(CN/PEG 50:50) scaffolds showed a significant indirect antimicrobial activity.

Functional Properties and Molecular Degradation of Schizostachyum Brachycladum Bamboo Cellulose Nanofibre in PLA-Chitosan Bionanocomposites

The degradation and mechanical properties of potential polymeric materials used for green manufacturing are significant determinants. In this study, cellulose nanofibre was prepared from Schizostachyum brachycladum bamboo and used as reinforcement in the PLA/chitosan matrix using melt extrusion and compression moulding method. The cellulose nanofibre(CNF) was isolated using supercritical carbon dioxide and high-pressure homogenisation. The isolated CNF was characterised with transmission electron microscopy (TEM), FT-IR, zeta potential and particle size analysis. The mechanical, physical, and degradation properties of the resulting biocomposite were studied with moisture content, density, thickness swelling, tensile, flexural, scanning electron microscopy, thermogravimetry, and biodegradability analysis. The TEM, FT-IR, and particle size results showed successful isolation of cellulose nanofibre using this method. The result showed that the physical, mechanical, and degradation properties of PLA/chitosan/CNF biocomposite were significantly enhanced with cellulose nanofibre. The density, thickness swelling, and moisture content increased with the addition of CNF. Also, tensile strength and modulus; flexural strength and modulus increased; while the elongation reduced. The carbon residue from the thermal degradation and the glass transition temperature of the PLA/chitosan/CNF biocomposite was observed to increase with the addition of CNF. The result showed that the biocomposite has potential for green and sustainable industrial application.

Smart and Sustainable Hair Products Based on Chitin-Derived Compounds

According to previous research studies, consumers worldwide are searching for new natural-oriented hair products that are both skin and environmentally friendly. Worldwide waste and air pollution, with the consequent environmental disasters, represent the greatest risk to human health and economy, further increased by the COVID-19 pandemic. Among others, non-biodegradable molecules are present in hair products (fossil-based additives, surfactants, etc.) and macromolecules (plastics). Plastics waste is considered the most serious problem, representing a forecast amount of 460 million tons per year by 2030, 12% of which is reused or recycled. Most plastics consumed, therefore, go to landfills and incineration, also if their recycling is considered an important driver of industrial profitability. Thus, the use of biopolymers represents an interesting alternative to produce biodegradable goods and tissues. After an introduction to the worldwide waste problem and the hair structure, the present review proposes the possibility to make biodegradable tissues that, realized by chitin nanofibrils and nano-lignin as natural polymers, may be used to produce an innovative and smart cosmetic hairline. Chitin-derived compounds are considered interesting polymers to produce non-woven tissues able to repair the hair damages provoked by the aggressiveness of both the environment and some aggressive cosmetic treatments, such as setting, bleaching, permanent waving, and oxidative coloring. The possible activity, that positively charged polymers such as chitin could have, has been speculated, interfering with the constitution and organization of the hair fibrils’ structure, which is negatively charged. The possibility of selecting biopolymers for their packaging is also discussed. Moreover, the use of these biopolymers, obtained from forestry-agro-food waste, may be of help to safeguard the further consumption of natural raw materials, necessary for future generations, also maintaining the earth’s biodiversity.

Protein based packaging of plant origin: Fabrication, properties, recent advances and future perspectives

Huge plastic waste is receiving worldwide attention nowadays due to its resistance to degradation and toxicity on environmental components including humans. Improper disposal of plastics affect the food chain and compromise various activities of aquatic life. Each facet of the plastic waste problem requires a significant attention and compels its elimination from the environment due to its ecologically deleterious threats. Therefore, this problem of plastic pollution and issues related thereof merits an attention regarding the alternatives wherein biopolymer based packaging has a potential role to play. This line of research has received a renewed focus where biodegradable films are being developed from proteins which are obtained from animals (include fish myofibrillar protein, collagen, gelatine, etc), and plants especially graminacea (rice, wheat, maize, barley etc), leguminaceae (soya beans, pea, etc.), asteraceae (sunflower) but little attention has been paid towards the potential of aquatic plants for development of packaging material. The present review provides a comprehensive account of biodegradable films developed from plant proteins viz. soy protein, wheat gluten, corn zein and sunflower protein as emerging supplement to plastics. Moreover, this article also tip-offs the potential of macrophytes for fabrication of protein based packaging films incorporated with bioactive materials extracted from macrophytes.

Surface chain engineering of chitin nanocrystals towards tailoring the nucleating capacities for poly(β-hydroxybutyrate)

Chitin nanocrystal (ChNC) is good nucleation agent for aliphatic polyesters because of its high-energy surface. To moderate its nucleation activity, silane coupling agents with different chain lengths or functional groups were used to modify ChNCs in this work, and biodegradable poly(β-hydroxybutyrate) (PHB) was used as target polymer for crystallization study. Surface coupling of ChNCs improves their phase adhesion to PHB chain and weakens their nucleation activities. The alterations strongly depend on the surface chain structure of ChNCs: sulfhydryl silane-coupled ChNC shows lowered nucleation activity, whereas amino silane-coupled ChNCs even become antinucleation agents. The interfacial compatibility is vital to altered role of ChNCs and to following changes in spherulite growth and ring-banded morphology, which is further disclosed using Flory-Huggins interaction parameters and rheological responses as probes. This work provides useful information on tailoring the functions of ChNCs as nanoadditive for biodegradable aliphatic polyesters by the way of surface chain engineering.

Trends in Surgical and Beauty Masks for a Cleaner Environment

The surgical face mask (SFM) is a sheet medical device covering the mouth, nose and chin to protect the medical staff from the spread of respiratory droplets produced by the infective coughing or sneezing of hospitalized patients. On the other hand the beauty face mask (BFM) has been made by the same sheet but with a different aim—to protect the skin from pollution, acting as a hydrating and rejuvenation agent. Currently, both masks are made principally by non-biodegradable tissues, utilized to avoid the increasing great pollution invading our planet. Due to the diffusion of the current COVID-19 infection rate and the increasing consumption of skin care and beauty products, the waste of these masks, made principally by petrol-derived polymers, is creating further intolerable waste-invaded land and oceans. After an introduction to the aims, differences and market of the various masks, their productive means and ingredients are reported. These news are believed necessary to give the reader the working knowledge of these products, in the context of the bioeconomy, to better understand the innovative tissues proposed and realized by the biobased and biodegradable polymers. Thus, the possibility of producing biodegradable SFMs and BFMs, characterized for their effective antimicrobial and skin repairing activities or hydrating and antiaging activity, respectively. These innovative smart and biodegradable masks are requested from the majority of consumers oriented towards a future green environment. Giving this new sense of direction to their production and consumption, it will be possible to reduce the current waste, ranging worldwide at about 2 billion tons per year.

Biodegradable Polymeric Micro/Nano-Structures with Intrinsic Antifouling/Antimicrobial Properties: Relevance in Damaged Skin and Other Biomedical Applications

Bacterial colonization of implanted biomedical devices is the main cause of healthcare-associated infections, estimated to be 8.8 million per year in Europe. Many infections originate from damaged skin, which lets microorganisms exploit injuries and surgical accesses as passageways to reach the implant site and inner organs. Therefore, an effective treatment of skin damage is highly desirable for the success of many biomaterial-related surgical procedures. Due to gained resistance to antibiotics, new antibacterial treatments are becoming vital to control nosocomial infections arising as surgical and post-surgical complications. Surface coatings can avoid biofouling and bacterial colonization thanks to biomaterial inherent properties (e.g., super hydrophobicity), specifically without using drugs, which may cause bacterial resistance. The focus of this review is to highlight the emerging role of degradable polymeric micro- and nano-structures that show intrinsic antifouling and antimicrobial properties, with a special outlook towards biomedical applications dealing with skin and skin damage. The intrinsic properties owned by the biomaterials encompass three main categories: (1) physical–mechanical, (2) chemical, and (3) electrostatic. Clinical relevance in ear prostheses and breast implants is reported. Collecting and discussing the updated outcomes in this field would help the development of better performing biomaterial-based antimicrobial strategies, which are useful to prevent infections.

Maria H, Gopi S, Volova T, C. M. Fernandes S, Thomas S. Extraction of Nanochitin from Marine Resources and Fabrication of Polymer Nanocomposites: Recent Advances

Industrial sea food residues, mainly crab and shrimp shells, are considered to be the most promising and abundant source of chitin. In-depth understanding of the biological properties of chitin and scientific advancements in the field of nanotechnology have enabled the development of high-performance chitin nanomaterials. Nanoscale chitin is of great economic value as an efficient functional and reinforcement material for a wide range of applications ranging from water purification to tissue engineering. The use of polymers and nanochitin to produce (bio) nanocomposites offers a good opportunity to prepare bioplastic materials with enhanced functional and structural properties. Most processes for nanochitin isolation rely on the use of chemical, physical or mechanical methods. Chitin-based nanocomposites are fabricated by various methods, involving electrospinning, freeze drying, etc. This review discusses the progress and new developments in the isolation and physico-chemical characterization of chitin; it also highlights the processing of nanochitin in various composite and functional materials.

Bio-Based Packaging: Materials, Modifications, Industrial Applications and Sustainability

Environmental impacts and consumer concerns have necessitated the study of bio-based materials as alternatives to petrochemicals for packaging applications. The purpose of this review is to summarize synthetic and non-synthetic materials feasible for packaging and textile applications, routes of upscaling, (industrial) applications, evaluation of sustainability, and end-of-life options. The outlined bio-based materials include polylactic acid, polyethylene furanoate, polybutylene succinate, and non-synthetically produced polymers such as polyhydrodyalkanoate, cellulose, starch, proteins, lipids, and waxes. Further emphasis is placed on modification techniques (coating and surface modification), biocomposites, multilayers, and additives used to adjust properties especially for barriers to gas and moisture and to tune their biodegradability. Overall, this review provides a holistic view of bio-based packaging material including processing, and an evaluation of the sustainability of and options for recycling. Thus, this review contributes to increasing the knowledge of available sustainable bio-based packaging material and enhancing the transfer of scientific results into applications.

Sustainable Micro and Nano Additives for Controlling the Migration of a Biobased Plasticizer from PLA-Based Flexible Films

Plasticized poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blend-based films containing chitin nanofibrils (CN) and calcium carbonate were prepared by extrusion and compression molding. On the basis of previous studies, processability was controlled by the use of a few percent of a commercial acrylic copolymer acting as melt strength enhancer and calcium carbonate. Furthermore, acetyl n-tributyl citrate (ATBC), a renewable and biodegradable plasticizer (notoriously adopted in PLA based products) was added to facilitate not only the processability but also to increase the mechanical flexibility and toughness. However, during the storage of these films, a partial loss of plasticizer was observed. The consequence of this is not only correlated to the change of the mechanical properties making the films more rigid but also to the crystallization and development of surficial oiliness. The effect of the addition of calcium carbonate (nanometric and micrometric) and natural nanofibers (chitin nanofibrils) to reduce/control the plasticizer migration was investigated. The prediction of plasticizer migration from the films’ core to the external surface was carried out and the diffusion coefficients, obtained by regression of the experimental migration data plotted as the square root of time, were evaluated for different blends compositions. The results of the diffusion coefficients, obtained thanks to migration tests, showed that the CN can slow the plasticizer migration. However, the best result was achieved with micrometric calcium carbonate while nanometric calcium carbonate results were less effective due to favoring of some bio polyesters’ chain scission. The use of both micrometric calcium carbonate and CN was counterproductive due to the agglomeration phenomena that were observed.

Modification of PLA-Based Films by Grafting or Coating

Recently, the demand for the use of natural polymers in the cosmetic, biomedical, and sanitary sectors has been increasing. In order to meet specific functional properties of the products, usually, the incorporation of the active component is required. One of the main problems is enabling compatibility between hydrophobic and hydrophilic surfaces. Therefore, surface modification is necessary. Poly(lactide) (PLA) is a natural polymer that has attracted a lot ofattention in recent years. It is bio-based, can be produced from carbohydrate sources like corn, and it is biodegradable. The main goal of this work was the functionalization of PLA, inserting antiseptic and anti-inflammatory nanostructured systems based on chitin nanofibrils-nanolignin complexes ready to be used in the biomedical, cosmetics, and sanitary sectors. The specific challenge of this investigation was to increase the interaction between the hydrophobic PLA matrix with hydrophilic chitin-lignin nanoparticle complexes. First, chemical modification via the "grafting from" method using lactide oligomers was performed. Then, active coatings with modified and unmodified chitin-lignin nanoparticle complexes were prepared and applied on extruded PLA-based sheets. The chemical, thermal, and mechanical characterization of prepared samples was carried out and the obtained results were discussed.

3D Hierarchical, Nanostructured Chitosan/PLA/HA Scaffolds Doped with TiO2/Au/Pt NPs with Tunable Properties for Guided Bone Tissue Engineering

Bone tissue is the second tissue to be replaced. Annually, over four million surgical treatments are performed. Tissue engineering constitutes an alternative to autologous grafts. Its application requires three-dimensional scaffolds, which mimic human body environment. Bone tissue has a highly organized structure and contains mostly inorganic components. The scaffolds of the latest generation should not only be biocompatible but also promote osteoconduction. Poly (lactic acid) nanofibers are commonly used for this purpose; however, they lack bioactivity and do not provide good cell adhesion. Chitosan is a commonly used biopolymer which positively affects osteoblasts' behavior. The aim of this article was to prepare novel hybrid 3D scaffolds containing nanohydroxyapatite capable of cell-response stimulation. The matrixes were successfully obtained by PLA electrospinning and microwave-assisted chitosan crosslinking, followed by doping with three types of metallic nanoparticles (Au, Pt, and TiO2). The products and semi-components were characterized over their physicochemical properties, such as chemical structure, crystallinity, and swelling degree. Nanoparticles' and ready biomaterials' morphologies were investigated by SEM and TEM methods. Finally, the scaffolds were studied over bioactivity on MG-63 and effect on current-stimulated biomineralization. Obtained results confirmed preparation of tunable biomimicking matrixes which may be used as a promising tool for bone-tissue engineering.

Properties and Skin Compatibility of Films Based on Poly(Lactic Acid) (PLA) Bionanocomposites Incorporating Chitin Nanofibrils (CN)

Nanobiocomposites suitable for preparing skin compatible films by flat die extrusion were prepared by using plasticized poly(lactic acid) (PLA), poly(butylene succinate-co-adipate) (PBSA), and Chitin nanofibrils as functional filler. Chitin nanofibrils (CNs) were dispersed in the blends thanks to the preparation of pre-nanocomposites containing poly(ethylene glycol). Thanks to the use of a melt strength enhancer (Plastistrength) and calcium carbonate, the processability and thermal properties of bionanocomposites films containing CNs could be tuned in a wide range. Moreover, the resultant films were flexible and highly resistant. The addition of CNs in the presence of starch proved not advantageous because of an extensive chain scission resulting in low values of melt viscosity. The films containing CNs or CNs and calcium carbonate resulted biocompatible and enabled the production of cells defensins, acting as indirect anti-microbial. Nevertheless, tests made with Staphylococcus aureus and Enterobacter spp. (Gram positive and negative respectively) by the qualitative agar diffusion test did not show any direct anti-microbial activity of the films. The results are explained considering the morphology of the film and the different mechanisms of direct and indirect anti-microbial action generated by the nanobiocomposite based films.

Effect of Chitin Nanocrystals on Crystallization and Properties of Poly(lactic acid)-Based Nanocomposites

The crystalline phase of poly(lactic acid) (PLA) has crucial effects on its own properties and nanocomposites. In this study, the isothermal crystallization of PLA, triethyl citrate-plasticized PLA (PLA-TEC), and its nanocomposite with chitin nanocrystals (PLA-TEC-ChNC) at different temperatures and times was investigated, and the resulting properties of the materials were characterized. Both PLA and PLA-TEC showed extremely low crystallinity at isothermal temperatures of 135, 130, 125 °C and times of 5 or 15 min. In contrast, the addition of 1 wt % of ChNCs significantly improved the crystallinity of PLA under the same conditions owing to the nucleation effect of the ChNCs. The samples were also crystallized at 110 °C to reach their maximal crystallinity, and PLA-TEC-ChNC achieved 48% crystallinity within 5 min, while PLA and PLA-TEC required 40 min to reach a similar level. Moreover, X-ray diffraction analysis showed that the addition of ChNCs resulted in smaller crystallite sizes, which further influenced the barrier properties and hydrolytic degradation of the PLA. The nanocomposites had considerably lower barrier properties and underwent faster degradation compared to PLA-TEC110. These results confirm that the addition of ChNCs in PLA leads to promising properties for packaging applications.

3D Chitin Scaffolds of Marine Demosponge Origin for Biomimetic Mollusk Hemolymph-Associated Biomineralization Ex-Vivo

Structure-based tissue engineering requires large-scale 3D cell/tissue manufacture technologies, to produce biologically active scaffolds. Special attention is currently paid to naturally pre-designed scaffolds found in skeletons of marine sponges, which represent a renewable resource of biomaterials. Here, an innovative approach to the production of mineralized scaffolds of natural origin is proposed. For the first time, a method to obtain calcium carbonate deposition ex vivo, using living mollusks hemolymph and a marine-sponge-derived template, is specifically described. For this purpose, the marine sponge Aplysin aarcheri and the terrestrial snail Cornu aspersum were selected as appropriate 3D chitinous scaffold and as hemolymph donor, respectively. The formation of calcium-based phase on the surface of chitinous matrix after its immersion into hemolymph was confirmed by Alizarin Red staining. A direct role of mollusks hemocytes is proposed in the creation of fine-tuned microenvironment necessary for calcification ex vivo. The X-ray diffraction pattern of the sample showed a high CaCO3 amorphous content. Raman spectroscopy evidenced also a crystalline component, with spectra corresponding to biogenic calcite. This study resulted in the development of a new biomimetic product based on ex vivo synthetized ACC and calcite tightly bound to the surface of 3D sponge chitin structure.

Nanomaterials Derived from Fungal Sources-Is It the New Hype?

Greener alternatives to synthetic polymers are constantly being investigated and sought after. Chitin is a natural polysaccharide that gives structural support to crustacean shells, insect exoskeletons, and fungal cell walls. Like cellulose, chitin resides in nanosized structural elements that can be isolated as nanofibers and nanocrystals by various top-down approaches, targeted at disintegrating the native construct. Chitin has, however, been largely overshadowed by cellulose when discussing the materials aspects of the nanosized components. This Perspective presents a thorough overview of chitin-related materials research with an analytical focus on nanocomposites and nanopapers. The red line running through the text emphasizes the use of fungal chitin that represents several advantages over the more popular crustacean sources, particularly in terms of nanofiber isolation from the native matrix. In addition, many β-glucans are preserved in chitin upon its isolation from the fungal matrix, enabling new horizons for various engineering solutions.

Hybrid Bilayer PLA/Chitosan Nanofibrous Scaffolds Doped with ZnO, Fe3O4, and Au Nanoparticles with Bioactive Properties for Skin Tissue Engineering

Burns affect almost half a million of Americans annually. In the case of full-thickness skin injuries, treatment requires a transplant. The development of bioactive materials that promote damaged tissue regeneration constitutes a great alternative to autografts. For this reason, special attention is focused on three-dimensional scaffolds that are non-toxic to skin cells and can mimic the extracellular matrix, which is mainly composed of nanofibrous proteins. Electrospinning, which enables the preparation of nanofibers, is a powerful tool in the field of biomaterials. In this work, novel hybrid poly (lactic acid)/chitosan biomaterials functionalized with three types of nanoparticles (NPs) were successfully developed. ZnO, Fe3O4, and Au NPs were investigated over their morphology by TEM method. The top layer was obtained from PLA nanofibers, while the bottom layer was prepared from acylated chitosan. The layers were studied over their morphology by the SEM method and their chemical structure by FT-IR. To verify their potential in burn wound treatment, the scaffolds' susceptibility to biodegradation as well as moisture permeability were calculated. Also, biomaterials conductivity was determined in terms of electrostimulation. Finally, cytotoxicity tests were carried out by XTT assay and morphology analysis using both fibroblasts cell line and primary cells. The hybrid nanofibrous scaffolds displayed a great potential in tissue engineering.

Vegetable Additives in Food Packaging Polymeric Materials

Plants are the most abundant bioresources, providing valuable materials that can be used as additives in polymeric materials, such as lignocellulosic fibers, nano-cellulose, or lignin, as well as plant extracts containing bioactive phenolic and flavonoid compounds used in the healthcare, pharmaceutical, cosmetic, and nutraceutical industries. The incorporation of additives into polymeric materials improves their properties to make them suitable for multiple applications. Efforts are made to incorporate into the raw polymers various natural biobased and biodegradable additives with a low environmental fingerprint, such as by-products, biomass, plant extracts, etc. In this review we will illustrate in the first part recent examples of lignocellulosic materials, lignin, and nano-cellulose as reinforcements or fillers in various polymer matrices and in the second part various applications of plant extracts as active ingredients in food packaging materials based on polysaccharide matrices (chitosan/starch/alginate).

Flat Die Extruded Biocompatible Poly(Lactic Acid) (PLA)/Poly(Butylene Succinate) (PBS) Based Films

Biodegradable polymers are promising materials for films and sheets used in many widely diffused applications like packaging, personal care products and sanitary products, where the synergy of high biocompatibility and reduced environmental impact can be particularly significant. Plasticized poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blend-based films, showing high cytocompatibility and improved flexibility than pure PLA, were prepared by laboratory extrusion and their processability was controlled by the use of a few percent of a commercial melt strength enhancer, based on acrylic copolymers and micro-calcium carbonate. The melt strength enhancer was also found effective in reducing the crystallinity of the films. The process was upscaled by producing flat die extruded films in which elongation at break and tear resistance were improved than pure PLA. The in vitro biocompatibility, investigated through the contact of flat die extruded films with cells, namely, keratinocytes and mesenchymal stromal cells, resulted improved with respect to low density polyethylene (LDPE). Moreover, the PLA-based materials were able to affect immunomodulatory behavior of cells and showed a slight indirect anti-microbial effect. These properties could be exploited in several applications, where the contact with skin and body is relevant.

Properties and Characterization of a PLA-Chitin-Starch Biodegradable Polymer Composite

This paper presents a comparison on the effects of blending chitin and/or starch with poly(lactic acid) (PLA). Three sets of composites (PLA–chitin, PLA–starch and PLA–chitin–starch) with 92%, 94%, 96% and 98% PLA by weight were prepared. The percentage weight (wt.%) amount of the chitin and starch incorporated ranges from 2% to 8%. The mechanical, dynamic mechanical, thermal and microstructural properties were analyzed. The results from the tensile strength, yield strength, Young’s modulus, and impact showed that the PLA–chitin–starch blend has the best mechanical properties compared to PLA–chitin and PLA–starch blends. The dynamic mechanical analysis result shows a better damping property for PLA–chitin than PLA–chitin–starch and PLA–starch. On the other hand, the thermal property analysis from thermogravimetry analysis (TGA) shows no significant improvement in a specific order, but the glass transition temperature of the composite increased compared to that of neat PLA. However, the degradation process was found to start with PLA–chitin for all composites, which suggests an improvement in PLA degradation. Significantly, the morphological analysis revealed a uniform mix with an obvious blend network in the three composites. Interestingly, the network was more significant in the PLA–chitin–starch blend, which may be responsible for its significantly enhanced mechanical properties compared with PLA–chitin and PLA–starch samples.

Chitin Nanofibrils and Nanolignin as Functional Agents in Skin Regeneration

Chitin and lignin, by-products of fishery and plant biomass, can be converted to innovative high value bio- and eco-compatible materials. On the nanoscale, high antibacterial, anti-inflammatory, cicatrizing and anti-aging activity is obtained by controlling their crystalline structure and purity. Moreover, electropositive chitin nanofibrlis (CN) can be combined with electronegative nanolignin (NL) leading to microcapsule-like systems suitable for entrapping both hydrophilic and lipophilic molecules. The aim of this study was to provide morphological, physico-chemical, thermogravimetric and biological characterization of CN, NL, and CN-NL complexes, which were also loaded with glycyrrhetinic acid (GA) as a model of a bioactive molecule. CN-NL and CN-NL/GA were thermally stable up to 114 °C and 127 °C, respectively. The compounds were administered to in vitro cultures of human keratinocytes (HaCaT cells) and human mesenchymal stromal cells (hMSCs) for potential use in skin contact applications. Cell viability, cytokine expression and effects on hMSC multipotency were studied. For each component, CN, NL, CN-NL and CN-NL/GA, non-toxic concentrations towards HaCaT cells were identified. In the keratinocyte model, the proinflammatory cytokines IL-1α, IL-1 β, IL-6, IL-8 and TNF-α that resulted were downregulated, whereas the antimicrobial peptide human β defensin-2 was upregulated by CN-LN. The hMSCs were viable, and the use of these complexes did not modify the osteo-differentiation capability of these cells. The obtained findings demonstrate that these biocomponents are cytocompatible, show anti-inflammatory activity and may serve for the delivery of biomolecules for skin care and regeneration.

Synthesis and Applications of Biopolymer Composites

In recent years, there has been a growing demand for a clean and pollution-free environment and an evident target to minimizing fossil fuel [...].

Cosmetic Packaging to Save the Environment: Future Perspectives

Consumer awareness about the damages that plastic packaging waste cause to the environment, coupled with bio-economy and circular economy policies, are pushing plastic packaging versus the use of bio-based and biodegradable materials. In this contest, even cosmetic packaging is looking for sustainable solutions, and research is focusing on modifying bio-based and biodegradable polymers to meet the challenging requirements for cosmetic preservation, while maintaining sustainability and biodegradability. Several bio-based and biodegradable polymers such as poly(lactic acid), polyhydroxyalkanoates, polysaccharides, etc., are available, and some first solutions for both rigid and flexible packaging are already present on the market, while many others are under study and optimization. A fruitful cooperation among researchers and industries will drive the cosmetic sector toward being more ecological and contributing to save our environment.

A New Carrier for Advanced Cosmeceuticals

Cosmetic products are generally formulated as emulsions, ointments, solutions or powders containing active ingredients. According to EU legislation, a cosmetic product is “any substance or preparation intended to be placed in contact with the various external parts of the human body with a view exclusively or mainly to cleaning, perfuming them, changing their appearance, and/or correcting body odors and/or protecting them or keeping them in good conditions”. However, science advancement in both active carriers and ingredients has streamlined the process through which many cosmetic products by their delivery systems can induce modifications on the skin physiology. This is the reason why Reed and Kligman redefined these products as “cosmeceuticals”, which refers to the combination of cosmetics and pharmaceuticals. Until recently, the term of cosmeceuticals has not had legal significance. The so-called cosmeceuticals, in fact, may induce modifications on the skin physiology, modifying, for example, transepidermal water loss, keratinocytes cohesion and turnover, modulating the inflammatory cascade, and/or altering the surface microbiota by the activity of the preservatives content. For these reasons, they are claimed to have medical or drug-like benefits. Naturally, their effectiveness on minor skin disorders or mild skin abnormalities has to be shown by in vitro and in vivo studies. On the other hand, their formulations contain emulsifiers, preservatives, and other chemicals which, by their cumulative use, may provoke side effects, such as allergic and/or sensitization phenomena. Moreover, many ingredients and packaging for such products are not biodegradable. In this study, we would like to introduce an innovative category of cosmeceuticals made by biodegradable nonwoven tissues. These cosmeceutical tissues, produced through the use of natural fibers, may bind different active ingredients and therefore become effective as antibacterial, anti-inflammatory, sun-protective, whitening, or anti-aging products, depending on the ingredient(s) used. Differently from the usual cosmetics, they do not contain preservatives, emulsifiers, colors, and other chemicals. They can be applied as dried tissue on wet skin, remaining in loco for around 30 min, slowly releasing the active ingredients entrapped into the fibers. It is interesting to underline that the tissue, acting as a carrier, has its own effectiveness via chitin and lignin polymers with an antibacterial and anti-inflammatory activity. When hydrolyzed by the human microbiota enzymes, they give rise to ingredients used as cell nourishment or energy. This paper will review part of the scientific research results, supporting this new category of biodegradable cosmetic products known as facial mask sheets.