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This study aimed to investigate the impact of plastic particles on cell viability and tissue toxicity. The cells were subjected to incubation with plastic particles immobilized in agar gels, resulting in minimal cell death and cytotoxicity. Furthermore, direct exposure of various cell types to suspended plastic particles showed negligible effects on cell viability, with no observed lysis or growth inhibition. Staining techniques revealed minimal plastic particle‐induced cell death, with the majority of cells remaining viable. However, histological evaluations of mouse tissues demonstrated that the nondegradable low‐density poly(ethylene) (LDPE) groups exhibited severe irritation, characterized by an excessive presence of macrophages, neutrophils, fibrosis, fat infiltration, and increased blood vessel formation in subcutaneous tissue. In contrast, biodegradable neat poly(butylene succinate) (KRICT‐PBS) and cellulose nanocrystals/PBS nanocomposite (CNC‐PBS) groups induced minimal toxicity. Interestingly, the intravenous injection of KRICT‐PBS and CNC‐PBS degradate solutions in mice exhibited mild toxicity, suggesting no significant damage to normal kidney and liver function. [ABSTRACT FROM AUTHOR]

Recent advancements in the utilization of naturally derived nanocellulose and nanochitin/chitosan have opened new avenues for self‐cleaning and purification applications to address environmental challenges. This review highlights the unique structural properties of bio‐based nanofibers, which are typically rich in hydroxyl groups that enhance their functionality in various industrial sectors. Through appropriate chemical modification, they can perform specific functions facilitated by carboxylic acids or amine groups. We explored the mechanisms by which these materials facilitate oil/water separation, ultrafiltration, and self‐cleaning processes, including the incorporation of inorganic nanoparticles, such as TiO2, to improve hydrophilicity and oleophobicity. Furthermore, this review discusses innovative fabrication techniques, such as spray‐assisted layer‐by‐layer assembly, which enhance the performance of nanofiber‐based coatings. We examined the potential of these materials for diverse applications, including food packaging, wastewater treatment, and personal protective equipment, emphasizing their role in promoting sustainable industrial practices. As the global emphasis on eco‐friendly solutions intensifies, continued research and development of nanocellulose and nanochitin is expected to drive significant advancements in materials science, paving the way for greener technologies. [ABSTRACT FROM AUTHOR]

Self‐healing polymeric materials, which can repair physical damage, offer promising prospects for protective applications across various industries. Although prolonged durability and resource conservation are key advantages, focusing solely on mechanical recovery may limit the market potential of these materials. The unique physical properties of self‐healing polymers, such as interfacial reduction, seamless connection lines, temperature/pressure responses, and phase transitions, enable a multitude of innovative applications. In this perspective, the diverse applications of self‐healing polymers beyond their traditional mechanical strength are emphasized and their potential in various sectors such as food packaging, damage‐reporting, radiation shielding, acoustic conservation, biomedical monitoring, and tissue regeneration is explored. With regards to the commercialization challenges, including scalability, robustness, and performance degradation under extreme conditions, strategies to overcome these limitations and promote successful industrialization are discussed. Furthermore, the potential impacts of self‐healing materials on future research directions, encompassing environmental sustainability, advanced computational techniques, integration with emerging technologies, and tailoring materials for specific applications are examined. This perspective aims to inspire interdisciplinary approaches and foster the adoption of self‐healing materials in various real‐life settings, ultimately contributing to the development of next‐generation materials. [ABSTRACT FROM AUTHOR]

Despite that biodegradable plastics are perceived as environmentally friendly, there is a lack of comprehensive understanding of their fate in soil. Current Environmental, Social, and Governance (ESG) frameworks, along with new UNEP regulations on plastic pollution, necessitate scientific information on plastic degradation in soils for developing sustainable biodegradable plastics. In this study, we examined the degradation rates of two biodegradable plastics, poly(butylene adipate‐co‐terephthalate) (PBAT) and poly(lactic acid) (PLA), in a laboratory microcosm experiment using uncontaminated soil, with PBAT or PLA added at 8.3% (w/w). Our aim was to further understand the impact of these plastic types on soil properties and microbial communities under different incubation temperatures. Both PBAT and PLA treatments elevated cumulative CO2 efflux compared with the control soil incubated at 25 and 58°C. After 33 weeks, 9.2% and 6.1% of the added PBAT and PLA degraded, respectively, at 58°C, while only 2.3% of PBAT and 1.7% of PLA degraded at 25°C, implying slower degradation rates of PBAT and PLA under the lower temperature. Degradation at 58°C increased total soil carbon by 0.6%, 1.9%, and 4.3% for Control, PBAT, and PLA, respectively, and soil electrical conductivity by 0.17, 0.33, and 2.38 dS m−1, respectively, but decreased soil pH. Microbial diversity and richness decreased under thermophilic conditions at 58°C compared with that at 25°C. We conclude that the degradation of PBAT and PLA varies with environmental condition, and influences soil properties. [ABSTRACT FROM AUTHOR]

Among plastic items, single‐use straws are particularly detrimental to marine ecosystems because such straws, including those made of poly(lactic acid) (PLA), are sharp and extremely slowly degradable in the ocean. While paper straws are promising alternatives, they exhibit hydration‐induced swelling even when coated with a non‐degradable plastic coating and promote effervescence (fizzing) in soft drinks owing to their surface heterogeneities. In this study, upgraded paper straw is coated with poly(butylene succinate) cellulose nanocrystal (PBS/CNC) composites. CNC increases adhesion to paper owing to their similar chemical structures, optimizes crystalline PBS spherulites through effective nucleation, and reinforces the matrix through its anisotropic and rigid features. The straws are not only anti‐fizzing when used with soft drinks owing to their homogeneous and seamless surface coatings, but also highly water‐resistant and tough owing to their watertight surfaces. All degradable components effectively decompose under aerobic composting and in the marine environment. This technology contributes to United Nations Sustainable Development Goal 14 (Life Below Water). [ABSTRACT FROM AUTHOR]

Accumulation of microplastics (MPs) in agricultural environments has caused growing concern in recent years because of its detrimental impacts on soil quality, crop productivity and ecosystem function. This study was conducted to assess the impact of biochar on soil chemical and microbial properties in a MP‐contaminated soil under two moisture regimes. Soil was contaminated with 1% (w/w) of low‐density polyethylene MPs. Four types of standard biochar, that is, oil seed rape (OSR) biochar produced at 550°C (OSR 550) and 700°C (OSR 700) and soft wood pellet (SWP) biochar produced at 550°C (SWP 550) and 700°C (SWP 700), were applied at a rate of 5% (w/w). The control was maintained without MP addition. The samples were incubated in soil with two moisture regimes, that is, at 30% and 70% of the water holding capacity, and the soil chemical and microbiological properties were assessed after 100 days of incubation. OSR biochar application significantly increased soil pH (8.53–8.81) and electrical conductivity (0.51–0.58 dS/m) in both moisture regimes. The effect of biochar application on soil enzyme activity and microbial community composition did not show a clear trend. However, SWP 700 biochar improved soil enzyme activity compared with that of the control and improved bacterial diversity and evenness compared with those of other biochars, which was attributed to the high surface area available for microbial colonization. Low soil moisture content significantly reduced enzyme activity and bacterial richness even with biochar amendment, except for SWP 550 biochar. This study implies the suitability of biochar for improvement of soil quality in MP contaminated soil under both moisture regimes. However, further long‐term studies are needed to get a clear understanding on the impact of different types of biochar on MP‐contaminated soil. [ABSTRACT FROM AUTHOR]

Chemo‐biological upcycling of poly(ethylene terephthalate) (PET) developed in this study includes the following key steps: chemo‐enzymatic PET depolymerization, biotransformation of terephthalic acid (TPA) into catechol, and its application as a coating agent. Monomeric units were first produced through PET glycolysis into bis(2‐hydroxyethyl) terephthalate (BHET), mono(2‐hydroxyethyl) terephthalate (MHET), and PET oligomers, and enzymatic hydrolysis of these glycolyzed products using Bacillus subtilis esterase (Bs2Est). Bs2Est efficiently hydrolyzed glycolyzed products into TPA as a key enzyme for chemo‐enzymatic depolymerization. Furthermore, catechol solution produced from TPA via a whole‐cell biotransformation (Escherichia coli) could be directly used for functional coating on various substrates after simple cell removal from the culture medium without further purification and water‐evaporation. This work demonstrates a proof‐of‐concept of a PET upcycling strategy via a combination of chemo‐biological conversion of PET waste into multifunctional coating materials. [ABSTRACT FROM AUTHOR]

The demand for face masks is increasing exponentially due to the coronavirus pandemic and issues associated with airborne particulate matter (PM). However, both conventional electrostatic‐ and nanosieve‐based mask filters are single‐use and are not degradable or recyclable, which creates serious waste problems. In addition, the former loses function under humid conditions, while the latter operates with a significant air‐pressure drop and suffers from relatively fast pore blockage. Herein, a biodegradable, moisture‐resistant, highly breathable, and high‐performance fibrous mask filter is developed. Briefly, two biodegradable microfiber and nanofiber mats are integrated into a Janus membrane filter and then coated by cationically charged chitosan nanowhiskers. This filter is as efficient as the commercial N95 filter and removes 98.3% of 2.5 µm PM. The nanofiber physically sieves fine PM and the microfiber provides a low pressure differential of 59 Pa, which is comfortable for human breathing. In contrast to the dramatic performance decline of the commercial N95 filter when exposed to moisture, this filter exhibits negligible performance loss and is therefore multi‐usable because the permanent dipoles of the chitosan adsorb ultrafine PM (e.g., nitrogen and sulfur oxides). Importantly, this filter completely decomposes within 4 weeks in composting soil. [ABSTRACT FROM AUTHOR]

Well‐known hard‐template methods for nitrogen (N)‐doped chiral carbon nanomaterials require complicated construction and removal of the template, high‐temperature pyrolysis, harsh chemical treatments, and additional N‐doping processes. If naturally occurring chiral nematic chitin nanostructures [(C8H13NO5)n] in exoskeletons were wholly transformed into an N‐doped carbon, this would be an efficient and sustainable method to obtain a useful chiral nanomaterial. Here, a simple, sacrificial‐template‐free, and environmentally mild method was developed to produce an N‐doped chiral nematic carbon‐sheath nanofibril hydrogel with a surface area >300 m2 g−1 and enantioselective properties from renewable chitin biomass. Calcium‐saturated methanol physically exfoliated bulk chitin and produced a chiral nematic nanofibril hydrogel. Hydrothermal treatment of the chiral chitin hydrogel at 190 °C produced an N‐doped chiral carbon‐sheath nanofibril hydrogel without N‐doping. This material preferentially adsorbed d‐lactic acid over l‐lactic acid and produced 16.3 % enantiomeric excess of l‐lactic acid from a racemic mixture. [ABSTRACT FROM AUTHOR]

Three of the major impediments to using hydroxyapatite (HAp)-collagen composites for hard tissue repair are the difficulties in anisotropic growth of HAp, in functional collagen production, and in their cross-linking. To solve these problems, we fabricated HAp-based composites for hard tissue repair by using chitosan as a collagen matrix substitute, and dopamine as a replacement for aldehyde-based cross-linkers. In the presence of chitosan and dopamine, the HAp particles grew anisotropically in a needle shape with an aspect ratio of ∼4.4. The needle-shaped HAp particles were dispersed well in the chitosan matrix, and dopamine-mediated cross-linking enhanced the stiffness and reduced swelling in the presence of water. The composite is too weak for use in hard tissue repair, but could be used for curing dentin sensitivity by blocking and remineralization on dentinal tubules, and in drug-delivery applications. [ABSTRACT FROM AUTHOR]

Chitosan is one of the most widely used structural polymers for biomedical applications because it has many favorable properties. However, one of the most critical drawbacks regarding the use of chitosan as a biomedical material is its poor mechanical properties in wet conditions. Here, we designed a method to improve the mechanical properties of chitosan in wet conditions and minimized the swelling behavior of chitosan film due to water adsorption by mimicking the sclerotization of insect cuticles and squid beaks, that is, catechol-meditated crosslinking. The biomimetic chitosan composite film was prepared by mixing chitosan with l-3,4-dihydroxyphenylalanine (DOPA) as a catecholic crosslinker and sodium periodate as an oxidant. The catechol-meditated crosslinking provided a sevenfold enhancement in the stiffness in wet conditions compared to pure chitosan films and reduced the swelling behavior of the chitosan film. This strategy expands the possible applications for the use of chitosan composites as load-bearing biomaterials. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29: 505-512, 2013 [ABSTRACT FROM AUTHOR]

Biocatalysis, catechol, esterase, poly(ethylene terephthalate), upcycling Cover Feature: Chemo-Biological Upcycling of Poly(ethylene terephthalate) to Multifunctional Coating Materials (ChemSusChem 19/2021) Keywords: biocatalysis; catechol; esterase; poly(ethylene terephthalate); upcycling EN biocatalysis catechol esterase poly(ethylene terephthalate) upcycling 3977 3977 1 10/07/21 20211005 NES 211005 B The Cover Feature b shows a direct chemo-biological upcycling of poly(ethylene terephthalate) (PET) into a functional coating agent through a combination of chemo-enzymatic depolymerization and biotransformation. [Extracted from the article]

Biodegradable Facemasks: Biodegradable, Efficient, and Breathable Multi-Use Face Mask Filter (Adv. Sci. 6/2021) In article number 2003155, Jeyoung Park, Dongyeop X. Oh, Sung Yeon Hwang, and co-workers report a biodegradable, moisture-resistant, highly efficient, and breathable face mask filter based on easy-to obtain poly(butylene succinate) coated with chitosan nanowhiskers. Integrated microfiber/nanofiber mats present a particulate matter removal efficiency as high as the commercial N95 filter due to a combination of physical sieving and electrostatic adsorption. [Extracted from the article]

Highlights from the article: Cover Feature: The Renewable and Sustainable Conversion of Chitin into a Chiral Nitrogen-Doped Carbon-Sheath Nanofiber for Enantioselective Adsorption (ChemSusChem 14/2019) B The Cover Feature b shows a sacrificial-template-free and environmentally mild method for the production of N-doped chiral nematic carbon nanofibril hydrogel from renewable chitin biomass. This material has enantioselective properties, selectively adsorbs d-lactic acid over l-lactic acid, and enriches a racemic solution to one with 16.3 % enantiomeric excess.