Sustainable Bioplastic Made from Biomass DNA and Ionomers

Bioinspired DNA Plastics with Brick-and-Mortar Structure: Enhanced Toughness, Recyclability, and Degradability

Bio-based plastics offer the advantage of biodegradability over traditional petroleum-based plastics, enabling natural reintegration into the environment and positioning them as a more sustainable alternative. DNA, as a natural biopolymer, exhibits excellent biocompatibility and degradability. However, the mechanical strength of currently biomass DNA-based materials is inferior to that of other bio-based and petroleum-based plastics. In this work, DNA plastics with a ″brick-and-mortar" structure were fabricated using DNA extracted from onions through bidirectional freezing, water vapor annealing, and compression densification. This biomimetic design significantly enhances the fracture toughness (∼1.5 MPa·m1/2) while possessing a high elastic modulus (∼560 MPa) of DNA plastic, making it superior or comparable to existing bio-based plastics and petroleum-based plastics, and thus positioning it as a potential structural material. Analysis of crack propagation behavior in DNA plastics reveals that their high toughness stems from a hierarchical ″brick-and-mortar″ structure operating across multiple length scales, facilitating a multiscale fracture process from macroscopic to molecular levels. Furthermore, these DNA plastics can be efficiently recycled in aqueous environments and fully biodegraded by enzymes, demonstrating strong environmental friendliness and significant potential for sustainable development.

DNA-Based Networks Formed by Coordination Cross-Linking of DNA with Metal-Organic Polyhedra: From Gels to Aerogels to Hydrogels

Herein, we introduce a supramolecular method to form DNA-based networks by cross-linking DNA with Rh(II)-based metal-organic polyhedra (MOPs), which entails coordination of DNA to the exohedral Rh(II) axial sites of the MOP. The resultant highly connected networks can then be processed into gels, porous aerogels, or hydrogels, exhibiting properties suitable for pollutant removal and drug release.

Coassembly of hybrid microscale biomatter for robust, water-processable, and sustainable bioplastics

Unlike conventional methods that typically involve extracting biopolymers/monomers from biomass using lots of hazardous chemicals and high energy, the direct utilization of biological matter (biomatter) without extraction offers a more sustainable alternative for bioplastic production. However, it often suffers from insufficient mechanical performances or limited processabilities. Herein, we proposed a hybrid microscale biomatter coassembly strategy that leverages the interactions between the inherent microarchitectures of waste cotton fiber and pollen particles. With minimal preprocessing, they form a castable slurry that can spontaneously organize into a dense fiber-laminate bioplastic network, exhibiting high mechanical properties (52.22 megapascals and 2.24 gigapascals) without using toxic organic chemicals or heavy machinery. The resulting bioplastic features controlled hydration-induced microstructural disassembly/reassembly, enabling water-based processability into complex, dynamic architectural systems. In addition, it demonstrates good biodegradability, closed-loop recyclability, and satisfactory environmental benefits, outperforming most common plastics. This study provides an instant nature-derived paradigm for bioplastics' sustainable production, processing, and recycling, offering a promising solution for facilitating eco-friendly advanced applications.

Solvent-Driven Synthesis of DNA-Based Liquid Crystalline Organogels with Extraordinary Stretchability, Self-Healing, and Higher-Order Structural Assembly

The fabrication of liquid crystalline (LC) organogel via supramolecular interactions between Deoxyribonucleic acid (DNA) and lyotropic cationic surfactant containing cyanobiphenyl moiety is reported. The fabricated organogel endows dominantly viscous behavior in dimethyl sulfoxide (DMSO) and elastic behavior in n-propanol (n-PrOH), respectively. By judiciously controlling the viscosity, DMSO organogels can be drawn to form a fiber with an elongation of up to 4.6 × 103%, emphasizing extraordinary stretchability. Higher-order structures, such as yarn and a co-alignment matrix for anisotropic particles, can be produced by assembling a single fiber. On the other hand, free-standing n-PrOH organogels demonstrate a remarkable storage modulus of 105 Pa and manifest self-healing properties. Finally, a sustainable method by transforming n-PrOH gel into an aerogel through critical point drying (CPD), enabling its use as an adsorbent while simultaneously enhancing its reusability is proposed. It is envisaged that these DNA-based organogels, through conceivable combinations between DNA as a building block and cationic surfactant with functionalities as a counterpart, will contribute to significant progress in DNA-based multi-functional organogels.

Opportunities and Challenges of DNA Materials toward Sustainable Development Goals

Sustainable development represents a significant and pressing challenge confronting the global community at present. A wide variety of macroscopic engineering systems has been developed to promote sustainable development. Recent advancements in DNA materials have showcased their substantial contributions toward achieving sustainable development goals (SDGs). Compared to nonbiological materials, DNA materials possess exceptional properties such as genetic functionality, molecular programmability, recognition capabilities, and biocompatibility. These unique characteristics enable DNA materials to serve as general and versatile substrates beyond their genetic role. Consequently, they can be used to develop DNA-based engineering systems that offer versatile solutions to support sustainable development. In this Perspective, we critically examine the opportunities that DNA-based engineering systems present in contributing to the achievement of the SDGs within various real-world scenarios. We establish direct relationships between DNA-based engineering systems and the SDGs, highlighting their inherent merits in accelerating sustainable development. Furthermore, in order to successfully achieve SDGs, we address the challenges associated with these systems and emphasize the urgent need for developing multifunctional, reliable, biosafe, and intelligent DNA-based engineering systems to overcome these challenges.

Mineral Plastics and Gels from Multi-Arm Ionomers

Plastic production and waste are a growing menace that affects the soil, the marine environment, and the air in a cumulative manner. The demand for mineral and bioplastics from renewable and biodegradable materials has therefore increased in all relevant sectors. The use of currently available degradable plastics is, however, limited by their poor mechanical properties and high production costs. In addition, many of today's plastics undergo uncontrolled biodegradation processes that involve harsh or expensive conditions and which may last from months to years. Here, the advantages of using multi-arm polymers for the production of sustainable mineral plastics are presented. A 4-arm poly(acrylic acid) is synthesized via atom transfer radical polymerization and is reacted with divalent calcium ions to obtain semi-liquid hydrogel or degradable plastic when dried. The mechanical properties of the different phases are evaluated and compared with linear poly(acrylic acid) of the same molecular weight. The multi-arm approach yielded improved mechanical characteristics, including self-healing and biodegradation without compromising other typical hydrogel characteristics. This concept of synthesizing multi-arm polymers with improved characteristics from building blocks of traditionally linear structures may be applicable to other mineral and bioplastic materials including acrylates, polysaccharides, and DNA.

Biotechnology for the degradation and upcycling of traditional plastics

Traditional plastics, predominantly derived from petrochemicals, are extensively utilized in modern industry and daily life. However, inadequate management and disposal practices have resulted in widespread environmental contamination, with polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, and polystyrene being the most prevalent pollutants. Biological methods for plastic degradation have garnered significant attention due to their cost-effectiveness and potential for resource recovery, positioning them as promising strategies for sustainable plastic waste management. While polyethylene terephthalate, characterized by its relatively less stable C-O bonds, has been extensively studied and demonstrates significant potential for biodegradation. In contrast, the biodegradation of other plastics remains a significant challenge due to the inherent stability of their C-C backbone structures. This review comprehensively examines the state-of-the-art biotechnology for treating these traditional plastics, focusing on: (1) the roles of specific microorganisms and enzymes, their taxonomic classifications, and the metabolic pathways involved in plastic biodegradation; and (2) a proposed two-stage hybrid approach integrating physicochemical and biological processes to enhance the biodegradation or upcycling of these traditional plastics. Additionally, the review highlights the critical role of multi-omics approaches and tailored strategies in enhancing the efficiency of plastic biodegradation while examining the impact of plastic molecular structures and additives on their degradation potential. It also addresses key challenges and delineates future research directions to foster the development of innovative biological methods for the effective and sustainable management of plastic waste.

Distribution of microplastics in the soils of a petrochemical industrial region in China: Ecological and Human Health Risks

Although microplastic pollution is a global concern, information on the distribution of microplastics in petroleum and petrochemical urban soils is limited. In this study, we investigated the occurrence, ecological risk, and human exposure risk of microplastics in different land-use types of soil in Daqing Administrative region, a prominent petroleum and petrochemical industrial base in China. Stereoscopic microscopy and Fourier transform infrared spectroscopy (μ-FTIR) were used to study the chemical composition and distribution characteristics of microplastics. We found that the abundance of microplastics in Daqing soil ranged from 714 to 11,122 items/kg, with the highest value in educational land and the lowest in parks and green land. The dominant particle size of microplastics was < 1 mm (65.7%), and the shape was mainly fiber (55.1%), with white (28.9%) and black (25.6%) as the predominant colors. The most common polymer types were rayon, polypropylene, and polyethylene. Using the potential ecological risk index (RI) and polymeric risk index (H), we found that all land-use types, except woodland (Level I), were classified into Level V of ecological risk, with the highest risk in industrial land (RI = 14,959.85, H = 588.31). The daily exposure of infants to microplastics was much higher than that of adults. These findings provide valuable data for the pollution and potential risk assessment of microplastics in urban and rural environments, suggesting the importance of taking action to minimize its harmful effects on ecological and human health. In order to control the pollution caused by microplastics, we suggest that people should reduce the unnecessary use of single-use plastic items, such as water bottles, plastic shopping bags, straws, etc. In addition, the government needs to strengthen rubbish collection to prevent plastic waste from leaking into the environment during the period from the rubbish bins to the landfills, and to build recycling systems to increase the recycling rate.

A Highly Sustainable Supramolecular Bioplastic Film with Superior Hydroplasticity and Biodegradability

Massive accumulation of postconsumer plastic waste in eco-system has raised growing environmental concerns. Sustainable end-of-life managements of the indispensable plastic are highly demanding and challenging in modern society. To relieve the plastic menace, herein we present a full life cycle sustainable supramolecular bioplastic made from biomass-derived polyelectrolyte (chitosan quaternary ammonium salt, QCS) and natural sodium fatty acid (sodium laurate, SL) through solid-phase molecular self-assembly (SPMSA), by which the QCS-SL complexes, precipitated from mixing the aqueous solutions, self-assemble to form bioplastic film by mildly pressing at room temperature. The QCS-SL bioplastic films display superior hydroplasticity owing to the water-activated molecular rearrangement and electrostatic bond reconstruction, which allows facile self-healing and reprocessing at room temperature to significantly extend the service lifetime of both products and raw materials. With higher water content, the dynamic electrostatic interactions and precipitation-dissolution equilibrium endow the QCS-SL bioplastic films with considerable solubility in water, which is promising to mitigate the plastic accumulation in aquatic environment. Because both QCS and SL are biocompatible and biodegradable, the dissolved QCS-SL films are nontoxic and environmentally friendly. Thus, this novel supramolecular bioplastic is highly sustainable throughout the whole life cycle, which is expected to open a new vista in sustainable plastic materials.

Bioinspired and biomimetic nucleobase-containing polymers: the effect of selective multiple hydrogen bonds

Bioinspired and biomimetic nucleobase-containing polymers are a series of polydisperse nucleic acid analogs, mainly obtaining through highly efficient and scalable step-growth or chain polymerizations. The combination of pendant nucleobase groups and various backbones endows the polymers/materials with selective multiple H-bonds under distinct conditions, demonstrating the broad applicability of this new family of polymeric materials. In this perspective, we critically summarize recent advances of bioinspired and biomimetic nucleobase-containing polymers and materials in both solution and the bulk. Then, we discuss the effect of multiple H-bonds between complementary nucleobases on the structures and properties of the nucleobase-containing polymers and materials. Selective multiple H-bonds between complementary nucleobases are feasible to modulate the polymer sequence and self-assembly behaviour, achieve templated polymerization, tune nanostructure morphologies and functions, and selectively bind with nucleic acids in various solutions. Meanwhile, bioinspired and biomimetic nucleobase-containing polymers are capable of forming robust polymeric materials such as hydrogels, bioplastics, elastomers, adhesives, and coatings by optimizing the inter- and intramolecular multiple H-bonding interactions. Further, the conclusions and outlook for future development and challenges of bioinspired and biomimetic nucleobase-containing polymers are also presented. This perspective presents useful guidelines for fabricating novel bioinspired and biomimetic polymers and materials through rational design of multiple H-bonds nucleobase interactions.

Chromatin inspired bio-condensation between biomass DNA and guanosine monophosphate produces all-nucleic hydrogel as a hydrotropic drug carrier

The integration of biomolecules into supramolecular nanostructures forms the basis of the natural world. Naturally occurring liquid-liquid phase separation resulting in biomolecular condensates has inspired the formation of biomolecule-based smart materials with multi-dimensional applications. A non-covalent bio-condensation between biomass DNA and guanosine monophosphate (GMP) has been described, mimicking chromatin folding and creating a unique "all-nucleic" DNA-GMP condensates. These condensates initiate the formation of G-quadruplex-based superstructures, assembling into super-helical fibres driven by synergistic hydrogen bonding and stacking, which have been thoroughly investigated. This simple, one-step method for the bio-condensation of biomass DNA leads to an "all-nucleic" hydrogel with higher-order self-assembly and excellent mechanical properties. While most of the reported DNA based biomaterials, including hydrogels, require precisely sequenced and molecularly architectured DNA building blocks, we have developed a simple, universal, and facile bio-condensation method that utilizes biomass DNA acquired from any bio-resource to fabricate DNA hydrogels. The hydrogel efficiently encapsulates and sustains the release of both hydrophilic and hydrophobic drugs, demonstrating its competency as a drug carrier. We believe this energy-efficient and low-cost method represents a new technique for using biomass DNA as building blocks for the next generation of soft materials.

DNA-Intercalating Supramolecular Hydrogels for Tunable Thermal and Viscoelastic Properties

Polymeric supramolecular hydrogels (PSHs) leverage the thermodynamic and kinetic properties of non-covalent interactions between polymer chains to govern their structural characteristics. As these materials are formed via endothermic or exothermic equilibria, their thermal response is challenging to control without drastically changing the nature of the chemistry used to join them. In this study, we introduce a novel class of PSHs utilizing the intercalation of double-stranded DNA (dsDNA) as the primary dynamic non-covalent interaction. The resulting dsDNA intercalating supramolecular hydrogels (DISHs) can be tuned to exhibit both endothermically or exothermically driven binding through strategic selection of intercalators. Bifunctional polyethylene glycol (MW~2000 Da) capped with intercalators of varying hydrophobicity, charge, and size (acridine, psoralen, thiazole orange, and phenanthridine) produced DISHs with comparable moduli (500-1000 Pa), but unique thermal viscoelastic responses. Notably, acridine-based cross-linkers displayed invariant and even increasing relaxation times with temperature, suggesting an endothermic binding mechanism. This methodology expands the set of structure-properties available to biomass-derived DNA biomaterials and promises a new material system where a broad set of thermal and viscoelastic responses can be obtained due to the sheer number and variety of intercalating molecules.

Bioresponsive Immunotherapeutic Materials

The human immune system is an interaction network of biological processes, and its dysfunction is closely associated with a wide array of diseases, such as cancer, infectious diseases, tissue damage, and autoimmune diseases. Manipulation of the immune response network in a desired and controlled fashion has been regarded as a promising strategy for maximizing immunotherapeutic efficacy and minimizing side effects. Integration of "smart" bioresponsive materials with immunoactive agents including small molecules, biomacromolecules, and cells can achieve on-demand release of agents at targeted sites to reduce overdose-related toxicity and alleviate off-target effects. This review highlights the design principles of bioresponsive immunotherapeutic materials and discusses the critical roles of controlled release of immunoactive agents from bioresponsive materials in recruiting, housing, and manipulating immune cells for evoking desired immune responses. Challenges and future directions from the perspective of clinical translation are also discussed.

Sustainable Plastics with High Performance and Convenient Processibility

Designing and making sustainable plastics is especially urgent to reduce their ecological and environmental impacts. However, it remains challenging to construct plastics with simultaneous high sustainability and outstanding comprehensive performance. Here, a composite strategy of in situ polymerizing a petroleum-based monomer with the presence of an industrialized bio-derived polymer in a quasi-solvent-free system is introduced, affording the plastic with excellent mechanical robustness, impressive thermal and solvent stability, as well as low energy, consumes during production, processing, and recycling. Particularly, the plastic can be easily processed into diverse shapes through 3D printing, injection molding, etc. during polymerization and further reprocessed into other complex structures via eco-friendly hydrosetting. In addition, the plastic is mechanically robust with Young's modulus of up to 3.7 GPa and tensile breaking strength of up to 150.2 MPa, superior to many commercially available plastics and other sustainable plastics. It is revealed that hierarchical hydrogen bonds in plastic predominate the well-balanced sustainability and performance. This work provides a new path for fabricating high-performance sustainable plastic toward practical applications, contributing to the circular economy.

DNA nanotechnology in ionic liquids and deep eutectic solvents

Nucleic acids have the ability to generate advanced nanostructures in a controlled manner and can interact with target sequences or molecules with high affinity and selectivity. For this reason, they have applications in a variety of nanotechnology applications, from highly specific sensors to smart nanomachines and even in other applications such as enantioselective catalysis or drug delivery systems. However, a common disadvantage is the use of water as the ubiquitous solvent. The use of nucleic acids in non-aqueous solvents offers the opportunity to create a completely new toolbox with unprecedented degrees of freedom. Ionic liquids (ILs) and deep eutectic solvents (DESs) are the most promising alternative solvents due to their unique electrolyte and solvent roles, as well as their ability to maintain the stability and functionality of nucleic acids. This review aims to be a comprehensive, critical, and accessible evaluation of how much this goal has been achieved and what are the most critical parameters for accomplishing a breakthrough.

Unlocking a Sustainable Future for Plastics: A Chemical-Enzymatic Pathway for Efficient Conversion of Mixed Waste to MHET and Energy-Saving PET Recycling

The heterogeneous monomers obtained from plastic waste degradation are unfavorable for PET recondensation and high-value derivative synthesis. Herein, we developed an efficient chemical-enzymatic approach to convert mixed plastic wastes into homogeneous mono-2-hydroxyethyl terephthalate (MHET) without downstream purification, benefiting from three discovered BHETases (KbEst, KbHyd, and BrevEst) in nature. Towards the mixed plastic waste, integrating the chemical K2CO3-driven glycolysis process with the BHETase depolymerization technique resulted in an MHET yield of up to 98.26 % in 40 h. Remarkably, BrevEst accomplished the highest BHET hydrolysis (~87 % efficiency in 12 h) for yielding analytical-grade MHET compared to seven state-of-the-art PET hydrolases (18 %-40 %). In an investigation combining quantum theoretical computations and experimental validations, we established a MHET-initiated PET repolymerization pathway. This shortcut approach with MHET promises to strengthen the valorization of mixed plastics, offering a substantially more efficient and energy-saving route for PET recycling.

A photoluminescent hydrogen-bonded biomass aerogel for sustainable radiative cooling

Passive radiant cooling is a potentially sustainable thermal management strategy amid escalating global climate change. However, petrochemical-derived cooling materials often face efficiency challenges owing to the absorption of sunlight. We present an intrinsic photoluminescent biomass aerogel, which has a visible light reflectance exceeding 100%, that yields a large cooling effect. We discovered that DNA and gelatin aggregation into an ordered layered aerogel achieves a solar-weighted reflectance of 104.0% in visible light regions through fluorescence and phosphorescence. The cooling effect can reduce ambient temperatures by 16.0°C under high solar irradiance. In addition, the aerogel, efficiently produced at scale through water-welding, displays high reparability, recyclability, and biodegradability, completing an environmentally conscious life cycle. This biomass photoluminescence material is another tool for designing next-generation sustainable cooling materials.

Electron-Rich Ru Supported on N-Doped Coffee Biochar for Selective Reductive Amination of Furfural to Furfurylamine

Highly selective synthesis of primary amines from renewable biomass has attracted increasing attention, but it still faces great challenges in chemical industry applications. In this study, an electron-rich Ru catalyst was constructed by doping N into coffee biochar using a one-pot carbonization method (Ru/NCB-600). Ru/NCB-600 showed high catalytic activity and yield for the reductive amination of furfural with green and cheap NH3 and H2. The excellent catalytic performance of Ru/NCB-600 was closely correlated to the formation of electron-rich Ruδ- species (Ruδ--Nxδ+), which endowed Ru/NCB-600 with an enhanced H2 adsorption and activation ability. Ru/NCB-600 showed a high formation rate of 95.6 gfurfurylamine·gRu-1·h-1 and a high yield of furfurylamine (98.6%) at 50 °C. Ru/NCB-600 can also be used for the reductive amination of various carbonyl compounds in good to excellent yield (95.4-99%). This study thus provides a potential pathway for the highly selective reductive amination of carbonyl compounds by regulating the electron density of Ru.

Chitinous Bioplastic Enabled by Noncovalent Assembly

Natural polymeric-based bioplastics usually lack good mechanical or processing performance. It is still challenging to achieve simultaneous improvement for these two usual trade-off features. Here, we demonstrate a full noncovalent mediated self-assembly design for simultaneously improving the chitinous bioplastic processing and mechanical properties via plane hot-pressing. Tannic acid (TA) is chosen as the noncovalent mediator to (i) increase the noncovalent cross-link intensity for obtaining the tough noncovalent network and (ii) afford the dynamic noncovalent cross-links to enable the mobility of chitin molecular chains for benefiting chitinous bioplastic nanostructure rearrangement during the shaping procedure. The multiple noncovalent mediated network (chitin-TA and chitin-chitin cross-links) and the pressure-induced orientation nanofibers structure endow the chitinous bioplastics with robust mechanical properties. The relatively weak chitin-TA noncovalent interactions serve as water mediation switches to enhance the molecular mobility for endowing the chitin/TA bioplastic with hydroplastic processing properties, rendering them readily programmable into versatile 2D/3D shapes. Moreover, the fully natural resourced chitinous bioplastic exhibits superior weld, solvent resistance, and biodegradability, enabling the potential for diverse applications. The full physical cross-linking mechanism highlights an effective design concept for balancing the trade-off of the mechanical properties and processability for the polymeric materials.

Preparation Strategies, Functional Regulation, and Applications of Multifunctional Nanomaterials-Based DNA Hydrogels

With the extensive attention of DNA hydrogels in biomedicine, biomaterial, and other research fields, more and more functional DNA hydrogels have emerged to match the various needs. Incorporating nanomaterials into the hydrogel network is an emerging strategy for functional DNA hydrogel construction. Surprisingly, nanomaterials-based DNA hydrogels can be engineered to possess favorable properties, such as dynamic mechanical properties, excellent optical properties, particular electrical properties, perfect encapsulation properties, improved magnetic properties, and enhanced antibacterial properties. Herein, the preparation strategies of nanomaterials-based DNA hydrogels are first highlighted and then different nanomaterial designs are used to demonstrate the functional regulation of DNA hydrogels to achieve specific properties. Subsequently, representative applications in biosensing, drug delivery, cell culture, and environmental protection are introduced with some selected examples. Finally, the current challenges and prospects are elaborated. The study envisions that this review will provide an insightful perspective for the further development of functional DNA hydrogels.

Nucleotide-based regenerated fiber production using salmon (Oncorhynchus keta) milt waste by solution spinning

The use of nucleic acid-derived fibers has not been developed in contrast to the traditional use of polysaccharide- and protein-based fibers in daily life. Salmon, Oncorhynchus keta, is an abundant fishery resource, and its milt contains a huge amount of DNA. Most of the milt is discarded because it degrades easily and is unsuitable for food consumption. DNA-based fibers are expected to possess functionality and mechanical strength because DNA is a polyanion with a high molecular weight. Here, using DNA extracted from the salmon milt, we produced nucleotide-based fibers. A solution spinning system was applied using ethanol as a coagulant. Adding the salt to the dope solution reduced the solubility of DNA, which was essential for the successful spinning of DNA-based fibers. The obtained fibers became insoluble in water by ultraviolet (UV) exposure. Fibril-like structures were detected on the fracture surface, and humidity influenced the conformational structure. This study focuses on the bulk-scale production of biodegradable DNA-based fibers. Therefore, it can be used not only for clothing and filters but also as a functional material to remove harmful pollutants released into the ocean, such as heavy metal ions and aromatic derivatives.

A biomass-derived dual crosslinked DNA-nanoparticle hydrogel for visible light-induced photodynamic bacterial inactivation

Sustainability in developing novel nanomaterials (NPs) from biomass sources is a challenging proposition mainly due to the difficulty of infusing or retaining desired chemical functionalities in the biomass substrate. In this study, we demonstrate the synthesis of DNA-nanoparticles (DNA-NP) from onion genomic DNA as a plant biomass source through controlled hydrothermal pyrolysis to retain functional groups in the NPs for predictable downstream chemical transformations. A dual crosslinking scheme was introduced that involves the DNA-NP to form a hydrogel. Chemical crosslinking was achieved through the formation of a Schiff base between the -CHO groups of glutaraldehyde and the amine functionality present on the DNA-NP surface as well as in the nucleobases of the dangling DNA strands of DNA-NP. Simultaneous physical entanglement was attained through hybridization-mediated self-assembly of the dangling DNA strands of the DNA-NP with untransformed onion genomic DNA. As a corollary of the dual crosslinking, the resulting hydrogel not only displayed remarkable mechanical strength but also showed self-healing properties. The ability of the DNA-NP to generate reactive oxygen species (ROS) with visible light irradiation is translated to the hydrogel, making the system potent for biofilm destruction. The high loading efficiency of the model drug ampicillin sodium (Amp) in the hydrogel was achieved which was released in four days. This hints towards the application of the hydrogel through combination antibiotic-antibacterial photodynamic treatment (APDT) as demonstrated here with both Gram-positive and Gram-negative bacteria.

Biomass RNA for the Controlled Synthesis of Degradable Networks by Radical Polymerization

Nucleic acids extracted from biomass have emerged as sustainable and environmentally friendly building blocks for the fabrication of multifunctional materials. Until recently, the fabrication of biomass nucleic acid-based structures has been facilitated through simple crosslinking of biomass nucleic acids, which limits the possibility of material properties engineering. This study presents an approach to convert biomass RNA into an acrylic crosslinker through acyl imidazole chemistry. The number of acrylic moieties on RNA was engineered by varying the acylation conditions. The resulting RNA crosslinker can undergo radical copolymerization with various acrylic monomers, thereby offering a versatile route for creating materials with tunable properties (e.g., stiffness and hydrophobic characteristics). Further, reversible-deactivation radical polymerization methods, such as atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT), were also explored as additional approaches to engineer the hydrogel properties. The study also demonstrated the metallization of the biomass RNA-based material, thereby offering potential applications in enhancing electrical conductivity. Overall, this research expands the opportunities in biomass-based biomaterial fabrication, which allows tailored properties for diverse applications.

A review of microalgae biofilm as an eco-friendly approach to bioplastics, promoting environmental sustainability

In this comprehensive review, we delve into the challenges hindering the large-scale production of microalgae-based bioplastics, primarily focusing on economic feasibility and bioplastic quality. To address these issues, we explore the potential of microalgae biofilm cultivation as a sustainable and highly viable approach for bioplastic production. We present a proposed method for producing bioplastics using microalgae biofilm and evaluate its environmental impact using various tools such as life cycle analysis (LCA), ecological footprint analysis, resource flow analysis, and resource accounting. While pilot-scale and large-scale LCA data are limited, we utilize alternative indicators such as energy efficiency, carbon footprint, materials management, and community acceptance to predict the environmental implications of commercializing microalgae biofilm-based bioplastics. The findings of this study indicate that utilizing microalgae biofilm for bioplastic production offers significant environmental sustainability benefits. The system exhibits low energy requirements and a minimal carbon footprint. Moreover, it has the potential to address the issue of wastewater by utilizing it as a carbon source, thereby mitigating associated problems. However, it is important to acknowledge certain limitations associated with the method proposed in this review. Further research is needed to explore and engineer precise techniques for manipulating microalgae biofilm structure to optimize the accumulation of desired metabolites. This could involve employing chemical triggers, metabolic engineering, and genetic engineering to achieve the intended goals. In conclusion, this review highlights the potential of microalgae biofilm as a viable and sustainable solution for bioplastic production. While acknowledging the advantages, it also emphasizes the need for continued synthetic studies to enhance the efficiency and reliability of this approach. By addressing the identified drawbacks and maximizing the utilization of advanced techniques, we can further harness the potential of microalgae biofilm in contributing to a more environmentally friendly and economically feasible bioplastic industry.

Marine plastics, circular economy, and artificial intelligence: A comprehensive review of challenges, solutions, and policies

Global plastic production is rapidly increasing, resulting in significant amounts of plastic entering the marine environment. This makes marine litter one of the most critical environmental concerns. Determining the effects of this waste on marine animals, particularly endangered organisms, and the health of the oceans is now one of the top environmental priorities. This article reviews the sources of plastic production, its entry into the oceans and the food chain, the potential threat to aquatic animals and humans, the challenges of plastic waste in the oceans, the existing laws and regulations in this field, and strategies. Using conceptual models, this study looks at a circular economy framework for energy recovery from ocean plastic wastes. It does this by drawing on debates about AI-based systems for smart management. In the last sections of the present research, a novel soft sensor is designed for the prediction of accumulated ocean plastic waste based on social development features and the application of machine learning computations. Plus, the best scenario of ocean plastic waste management with a concentration on both energy consumption and greenhouse gas emissions is discussed using USEPA-WARM modeling. Finally, a circular economy concept and ocean plastic waste management policies are modeled based on the strategies of different countries. We deal with green chemistry and the replacement of plastics derived from fossil sources.

Recastable assemblies of carbon dots into mechanically robust macroscopic materials

Assembly of nanoparticles into macroscopic materials with mechanical robustness, green processability, and recastable ability is an important and challenging task in materials science and nanotechnology. As an emerging nanoparticle with superior properties, macroscopic materials assembled from carbon dots will inherit their properties and further offer collective properties; however, macroscopic materials assembled from carbon dots solely remain unexplored. Here we report macroscopic films assembled from carbon dots modified by ureido pyrimidinone. These films show tunable fluorescence inherited from carbon dots. More importantly, these films exhibit collective properties including self-healing, re-castability, and superior mechanical properties, with Young's modulus over 490 MPa and breaking strength over 30 MPa. The macroscopic films maintain original mechanical properties after several cycles of recasting. Through scratch healing and welding experiments, these films show good self-healing properties under mild conditions. Moreover, the molecular dynamics simulation reveals that the interplay of interparticle and intraparticle hydrogen bonding controls mechanical properties of macroscopic films. Notably, these films are processed into diverse shapes by an eco-friendly hydrosetting method. The methodology and results in this work shed light on the exploration of functional macroscopic materials assembled from nanoparticles and will accelerate innovative developments of nanomaterials in practical applications.

Programmable DNA Hydrogel Provides Suitable Microenvironment for Enhancing TSPCS Therapy in Healing of Tendinopathy

Tendon stem/progenitor cells (TSPCs) therapy is a promising strategy for enhancing cell matrix and collagen synthesis, and regulating the metabolism of the tendon microenvironment during tendon injury repair. Nevertheless, the barren microenvironment and gliding shear of tendon cause insufficient nutrition supply, damage, and aggregation of injected TSPCs around tendon tissues, which severely hinders their clinical application in tendinopathy. In this study, a TSPCs delivery system is developed by encapsulating TSPCs within a DNA hydrogel (TSPCs-Gel) as the DNA hydrogel offers an excellent artificial extracellular matrix (ECM) microenvironment by providing nutrition for proliferation and protection against shear forces. This delivery method restricts TSPCs to the tendons, significantly extending their retention time. It is also found that TSPCs-Gel injections can promote the healing of rat tendinopathy in vivo, where cross-sectional area and load to failure of injured tendons in rats are significantly improved compared to the free TSPCs treatment group at 8 weeks. Furthermore, the potential healing mechanism of TSPCs-Gel is investigated by RNA-sequencing to identify a series of potential gene and signaling pathway targets for further clinical treatment strategies. These findings suggest the potential pathways of using DNA hydrogels as artificial ECMs to promote cell proliferation and protect TSPCs in TSPC therapy.

Constructing An All-Natural Bulk Structural Material from Surface-Charged Bamboo Cellulose Fibers with Enhanced Mechanical and Thermal Properties

Bamboo is widely distributed, rapidly regenerable, and incorporates long cellulose fibers, which make it one of the most lightweight and strong natural materials. Processing bamboo into a high-performance structural material for plastic replacement is highly promising but challenging. In this study, an all-natural, high-performance structural material is derived from natural bamboo with superior mechanical and thermal properties that benefit from the introduction of surface charge and further layer-by-layer assembly of bamboo cellulose fibers. The obtained modified bamboo fiber plate (MBFP) transcends the constraints of the natural size and anisotropy of bamboo, showing high flexural strength (ca. 179 MPa) and flexural modulus (ca. 12 GPa). Moreover, the product has an extremely low coefficient of thermal expansion (ca. 11.3×10^-6  K^-1 ), high thermal stability, and superior fire resistance. The excellent mechanical and thermal properties combined with the efficient and rational manufacturing process make MBFP a powerful plastic alternative for furniture, construction, and automotive industries.

Development of Salmon Sperm DNA/Regenerated Silk Bio-Based Films for Biomedical Studies on Human Keratinocyte HaCaT Cells under Solar Spectrum

In this study, we fabricated adhesive patches from silkworm-regenerated silk and DNA to safeguard human skin from the sun's rays. The patches are realized by exploiting the dissolution of silk fibers (e.g., silk fibroin (SF)) and salmon sperm DNA in formic acid and CaCl₂ solutions. Infrared spectroscopy is used to investigate the conformational transition of SF when combined with DNA; the results indicated that the addition of DNA provides an increase in the SF crystallinity. UV-Visible absorption and circular dichroism spectroscopy showed strong absorption in the UV region and the presence of B-form of DNA once dispersed in the SF matrix, respectively. Water absorption measurements as well as thermal dependence of water sorption and thermal analysis, suggested the stability of the fabricated patches. Biological results on cellular viability (MTT assay) of keratinocyte HaCaT cells after exposures to the solar spectrum showed that both SF and SF/DNA patches are photo-protective by increasing the cellular viability of keratinocytes after UV component exposure. Overall, these SF/DNA patches promise applications in wound dressing for practical biomedical purposes.

Soy Protein Isolate/Genipin-Based Nanoparticles for the Stabilization of Pickering Emulsion to Design Self-Healing Guar Gum-Based Hydrogels

Nowadays, stretchable self-healing hydrogels designed by biomass-based materials have gathered remarkable attention in numerous frontier fields such as wound healing, health monitoring issues, and electronic skin. In this study, soy protein isolate (SPI), a common plant protein, was cross-linked to nanoparticles (SPI NPs) by Genipin, (Gen) which was attracted from the native Geniposide. Oil-in-water (O/W) Pickering emulsion was formed by SPI NPs wrapping the linseed oil, and further implanted into poly(acrylic acid)/guar gum (PAA/GG)-based self-healing hydrogels by multiple reversible weak interactions. With the addition of Pickering emulsion, the hydrogels have achieved a remarkable self-healing ability (self-healing efficiency could reach 91.6% within 10 h) and mechanical properties (tensile strength of 0.89 MPa and strain of 853.2%). Therefore, these hydrogels with good reliable durability have outstanding application prospects in sustainable materials.

Surface Hydrophobization Provides Hygroscopic Supramolecular Plastics Based on Polysaccharides with Damage-Specific Healability and Room-Temperature Recyclability

Supramolecular materials with room-temperature healability and recyclability are highly desired because they can extend materials lifetimes and reduce resources consumption. Most approaches toward healing and recycling rely on the dynamically reversible supramolecular interactions, such as hydrogen, ionic and coordinate bonds, which are hygroscopic and vulnerable to water. The general water-induced plasticization facilitates the healing and reprocessing process but cause a troubling problem of random self-adhesion. To address this issue, here it is reported that by modifying the hygroscopic surfaces with hydrophobic alkyl chains of dodecyltrimethoxysilane (DTMS), supramolecular plastic films based on commercial raw materials of sodium alginate (SA) and cetyltrimethylammonium bromide (CTAB) display extraordinary damage-specific healability. Owing to the hydrophobic surfaces, random self-adhesion is eliminated even under humid environment. When damage occurs, the fresh surfaces with ionic groups and hydroxyl groups expose exclusively at the damaged site. Thus, damage-specific healing can be readily facilitated by water-induced plasticization. Moreover, the films display excellent room-temperature recyclability. After multiple times of reprocessing and re-modifying with DTMS, the rejuvenated films exhibit fatigueless mechanical properties. It is anticipated that this approach to damage-specific healing and room-temperature recycling based on surface hydrophobization can be applied to design various of supramolecular plastic polysaccharides materials for building sustainable societies.

Enzyme catalyzes ester bond synthesis and hydrolysis: The key step for sustainable usage of plastics

Petro-plastic wastes cause serious environmental contamination that require effective solutions. Developing alternatives to petro-plastics and exploring feasible degrading methods are two solving routes. Bio-plastics like polyhydroxyalkanoates (PHAs), polylactic acid (PLA), polycaprolactone (PCL), poly (butylene succinate) (PBS), poly (ethylene furanoate) s (PEFs) and poly (ethylene succinate) (PES) have emerged as promising alternatives. Meanwhile, biodegradation plays important roles in recycling plastics (e.g., bio-plastics PHAs, PLA, PCL, PBS, PEFs and PES) and petro-plastics poly (ethylene terephthalate) (PET) and plasticizers in plastics (e.g., phthalate esters, PAEs). All these bio- and petro-materials show structure similarity by connecting monomers through ester bond. Thus, this review focused on bio-plastics and summarized the sequences and structures of the microbial enzymes catalyzing ester-bond synthesis. Most of these synthetic enzymes belonged to α/β-hydrolases with conserved serine catalytic active site and catalyzed the polymerization of monomers by forming ester bond. For enzymatic plastic degradation, enzymes about PHAs, PBS, PCL, PEFs, PES and PET were discussed, and most of the enzymes also belonged to the α/β hydrolases with a catalytic active residue serine, and nucleophilically attacked the ester bond of substrate to generate the cleavage of plastic backbone. Enzymes hydrolysis of the representative plasticizer PAEs were divided into three types (I, II, and III). Type I enzymes hydrolyzed only one ester-bond of PAEs, type II enzymes catalyzed the ester-bond of mono-ester phthalates, and type III enzymes hydrolyzed di-ester bonds of PAEs. Divergences of catalytic mechanisms among these enzymes were still unclear. This review provided references for producing bio-plastics, and degrading or recycling of bio- and petro-plastics from an enzymatic point of view.

Fully recyclable multifunctional adhesive with high durability, transparency, flame retardancy, and harsh-environment resistance

Recyclable/reversible adhesives have attracted growing attention for sustainability and intelligence but suffer from low adhesion strength and poor durability in complex conditions. Here, we demonstrate an aromatic siloxane adhesive that exploits stimuli-responsive reversible assembly driven by π-π stacking, allowing for elimination and activation of interfacial interactions via infiltration-volatilization of ethanol. The robust cohesive energy from water-insensitive siloxane assembly enables durable strong adhesion (3.5 MPa shear strength on glasses) on diverse surfaces. Long-term adhesion performances are realized in underwater, salt, and acid/alkali solutions (pH 1-14) and at low/high temperatures (-10-90°C). With reversible assembly/disassembly, the adhesive is closed-loop recycled (~100%) and reused over 100 times without adhesion loss. Furthermore, the adhesive has unique combinations of high transparency (~98% in the visible light region of 400-800 nm) and flame retardancy. The experiments and theoretical calculations reveal the corresponding mechanism at the molecular level. This π-π stacking-driven siloxane assembly strategy opens up an avenue for high-performance adhesives with circular life and multifunctional integration.

Biomass derived self-assembled DNA-dot hydrogels for enhanced bacterial annihilation

Nanotization of biomass for interesting biomedical applications is still in the nascent stage with no visible market available products. While products derived from biomass DNA and protein have unquestionable biocompatibility, induction of desired properties needs careful manipulation of the biomolecules. Herein, for the first time, we report the transformation of onion derived biomass DNA into DNA-dots through its partial hydrothermal pyrolysis to induce improved mechanical and photophysical properties. The DNA-dots were further used as crosslinkers to create a hydrogel through hybridization-mediated self-assembly with untransformed genomic DNA. The DNA dot-DNA hydrogel sustainably delivers the ciprofloxacin antibiotic as well as produces on-demand reactive oxygen species (ROS) with visible light irradiation. This prompted us to explore the hydrogel as a topical formulation for combination antibiotic Antibacterial-Photodynamic Therapy (APDT) applications. Remarkable annihilation of E. coli and S. aureus, and most importantly two drug-resistant strains of E. coli, shows the success of our sustainable approach.

Hierarchical Assembly of Flexible Biopolymer Polyphosphate-Manganese into Nanosheets

Polyphosphate (polyP) is one of the most compact inorganic polyanionic biopolymers that participates in various physiological processes. However, the development of polyP-based nanomaterials is still in its infancy. Here, biocompatible polyphosphate-manganese nanosheets are designed and synthesized by a hierarchical assembly strategy. The thickness and the lateral size of the resulting polyP-Mn nanosheets (PMNSs) are 5 nm and 120-130 nm, respectively. Molecular dynamics simulations suggested that the polyP-hexadecyl trimethyl ammonium bromide flat structure possesses a strong aggregating capacity and serves as the template for the 2D assembly of polyP-Mn. The PMNSs can activate the inflammatory response of macrophages resulting in the recovery of innate immunological functions to inhibit tumor proliferation. This work has initiated a new direction in constructing layered polyP-based nanomaterials and provides guidance for biocompatible and biodegradable biopolymer-based materials in the regulation of innate responses.

Mechanically Robust, Self-Repairable, Shape Memory and Recyclable Ionomeric Elastomer Composites with Renewable Lignin via Interfacial Metal-Ligand Interactions

Lignin, the most abundant aromatic polymer in nature, is one of the most promising renewable feedstocks for value-added polymer products. However, it is challenging to prepare high-performance and multifunctional polymer materials with renewable lignin because of its poor compatibility with the elastomer matrix. In fact, lignin often requires solvent fractionation, chemical modification, or prohibitively expensive additives. This work develops a cost-effective strategy to prepare ionomeric elastomer composites based on a commercial carboxyl elastomer and a high content of lignin without purification or chemical modification. The compatibility between the elastomer and lignin is improved by the incorporation of zinc oxide which creates metal-ligand coordination at the interfaces between the carboxyl groups of the elastomer and the oxygen-bearing groups of the lignin. This results in fine dispersion of the lignin in the elastomer matrix, even when its content reaches 50 wt %. The lignin/elastomer composites show excellent mechanical properties, which are attributed to the reinforcing effect of the lignin domains and the presence of abundant sacrificial coordination bonds. Moreover, ionic bonds and ionic aggregates created by the neutralization of the zinc ions with the carboxyl groups of the elastomer behave as physical crosslinks which endow the composites with excellent recyclability; namely, their mechanical properties are retained or even improved after multiple reprocessing cycles. They also show good self-repairability and shape memory. Hence, this work may open up new avenues to utilize lignin as a renewable alternative to petroleum derivatives for designing and fabricating high-performance and multifunctional elastomer materials.

DNA Hydrogels in the Perspective of Mechanical Properties

Tailoring the mechanical properties has always been a key to the field of hydrogels in terms of different applications. Particularly, deoxyribonucleic acid (DNA) hydrogels offer an unambiguous way to precisely tune the mechanical properties, largely on account of their programmable sequences, abundant responding toolbox, and various ligation approaches. In this review, DNA hydrogels from the perspective of mechanical properties, from synthetic standpoint to different applications are introduced. The relationship between the structure and their mechanical properties in DNA hydrogels and the methods of regulating the mechanical properties of DNA hydrogels are specifically summarized. Furthermore, several recent applications of DNA hydrogels in relation to their mechanical properties are discussed. Benefiting from the tunability and flexibility, rational design of mechanical properties in DNA hydrogels provided unheralded interest from fundamental science to extensive applications. This article is protected by copyright. All rights reserved.

Hydrogen-Bonding Affords Sustainable Plastics with Ultrahigh Robustness and Water-Assisted Arbitrarily Shape Engineering

Herein, the supramolecular plastic-like hydrogel (SPH) is introduced as a platform to fabricate sustainable plastics with ultrahigh stiffness and strength as well as water-assisted arbitrarily shapeable capability. The transparent plastics are constructed from SPHs of cellulose ether/polycarboxylic acid complexes and demonstrate mechanical robustness with Young's modulus up to 3.4 GPa and tensile strength up to 124.0 MPa, superior or comparable to most common plastics. Meanwhile, the shape of the plastics can be reversibly engineered by air drying of the SPHs with diverse 2D/3D shapes and structures, which are generated conveniently via origami, kirigami, embossing, etc., in virtue of plastic deformation and shape memory effect of SPHs. On the basis of multi-dimensional infrared-spectral analysis, it is revealed that the dense acid-acid and acid-ether hydrogen (H)-bonding network in the plastic is responsible for the mechanical robustness while the evolution of water-polymer H-bonds into polymer-polymer H-bonds during air drying contributes to the shape fixing. This work provides a novel method of manufacturing sustainable plastics with simultaneous strong mechanical performance and convenient processibility from hydrogels with plastic-like mechanical behavior.

Application of Nucleic Acid Frameworks in the Construction of Nanostructures and Cascade Biocatalysts: Recent Progress and Perspective

Nucleic acids underlie the storage and retrieval of genetic information literally in all living organisms, and also provide us excellent materials for making artificial nanostructures and scaffolds for constructing multi-enzyme systems with outstanding performance in catalyzing various cascade reactions, due to their highly diverse and yet controllable structures, which are well determined by their sequences. The introduction of unnatural moieties into nucleic acids dramatically increased the diversity of sequences, structures, and properties of the nucleic acids, which undoubtedly expanded the toolbox for making nanomaterials and scaffolds of multi-enzyme systems. In this article, we first introduce the molecular structures and properties of nucleic acids and their unnatural derivatives. Then we summarized representative artificial nanomaterials made of nucleic acids, as well as their properties, functions, and application. We next review recent progress on constructing multi-enzyme systems with nucleic acid structures as scaffolds for cascade biocatalyst. Finally, we discuss the future direction of applying nucleic acid frameworks in the construction of nanomaterials and multi-enzyme molecular machines, with the potential contribution that unnatural nucleic acids may make to this field highlighted.