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Smallholder farmers and manufacturers in the Agri-Food sector face substantial challenges because of increasing circulation of counterfeit products (e.g., seeds), for which current countermeasures are implemented mainly at the secondary packaging level, and are generally vulnerable because of limited security guarantees. Here, by integrating biopolymer design with physical unclonable functions (PUFs), we propose a cryptographic protocol for seed authentication using biodegradable and miniaturized PUF tags made of silk microparticles. By simply drop casting a mixture of variant silk microparticles on a seed surface, tamper-evident PUF tags can be seamlessly fabricated on a variety of seeds, where the unclonability comes from the stochastic assembly of spectrally and visually distinct silk microparticles in the tag. Unique, reproducible, and unpredictable PUF codes are generated from both Raman mapping and microscopy imaging of the silk tags. Together, the proposed technology offers a highly secure solution for anticounterfeiting and product traceability in agriculture.

In semi-arid regions, water stress during seed germination and early seedling growth is the highest cause of crop loss. In nature, some seeds (for example, chia and basil) produce a mucilage-based hydrogel that creates a germination-promoting microenvironment by retaining water, regulating nutrient entry and facilitating interactions with beneficial microorganisms. Inspired by this strategy, a two-layered biopolymer-based seed coating has been developed to increase germination and water-stress tolerance in semi-arid, sandy soils. Seeds are coated with a silk/trehalose inner layer containing rhizobacteria and a pectin/carboxymethylcellulose outer layer that reswells upon sowing and acts as a water jacket. Using Phaseolus vulgaris (common bean) cultured under water-stress conditions in an experimental farm in Ben Guerir, Morocco, the proposed seed coating effectively delivered rhizobacteria to form root nodules, resulted in plants with better health and mitigated water stress in drought-prone marginal lands. A programmable seed coating technology has the potential to increase seed germination and water-stress tolerance in semi-arid, sandy soils. The seed coating consists of a silk/trehalose inner layer containing rhizobacteria and a pectin/carboxymethylcellulose outer layer that reswells upon sowing and acts as a water jacket. Coated common bean seeds showed better plant establishment in semi-arid soil.

New technologies that enhance soil biodiversity and minimize the use of scarce resources while boosting crop production are highly sought to mitigate the increasing threats that climate change, population growth, and desertification pose on the food infrastructure. In particular, solutions based on plant-growth-promoting bacteria (PGPB) bring merits of self-replication, low environmental impact, tolerance to biotic and abiotic stressors, and reduction of inputs, such as fertilizers. However, challenges in facilitating PGPB delivery in the soil still persist and include survival to desiccation, precise delivery, programmable resuscitation, competition with the indigenous rhizosphere, and soil structure. These factors play a critical role in microbial root association and development of a beneficial plant microbiome. Engineering the seed microenvironment with protein and polysaccharides is one proposed way to deliver PGPB precisely and effectively in the seed spermosphere. In this review, we will cover new advancements in the precise and scalable delivery of microbial inoculants, also highlighting the latest development of multifunctional rhizobacteria solutions that have beneficial impact on not only legumes but also cereals. To conclude, we will discuss the role that legislators and policymakers play in promoting the adoption of new technologies that can enhance the sustainability of crop production.

White wastes (unseparated plastics, face masks, textiles, etc.) pose a serious challenge to sustainable human development and the ecosystem and have recently been exacerbated due to the surge in plastic usage and medical wastes from COVID-19. Current recycling methods such as chemical recycling, mechanical recycling, and incineration require either pre-sorting and washing or releasing CO2. In this work, a carbon foam microwave plasma process is developed, utilizing plasma discharge to generate surface temperatures exceeding ∼3000 K in a N2 atmosphere, to convert unsorted white wastes into gases (H2, CO, C2H4, C3H6, CH4, etc.) and small amounts of inorganic minerals and solid carbon, which can be buried as artificial "coal". This process is self-perpetuating, as the new solid carbon asperities grafted onto the foam's surface actually increase the plasma discharge efficiency over time. This process has been characterized by in situ optical probes and infrared sensors and optimized to handle most of the forms of white waste without the need for pre-sorting or washing. Thermal measurement and modeling show that in a flowing reactor, the device can achieve locally extremely high temperatures, but the container wall will still be cold and can be made with cheap materials, and thus, a miniaturized waste incinerator is possible that also takes advantage of intermittent renewable electricity.

This perspective provides an overview of the micro-/nanofabrication methods developed for structural biopolymers, highlighting recent advances in the rapid and ease construction of complex and multifunctional silk fibroin-based devices by integrating top-down manufacturing with bottom-up molecular self-assembly. Of particular interest is the development of a new nanofabrication strategy that employs templated crystallization to direct silk fibroin folding and assembly from a suspension of disordered, random coil molecules to ordered, hierarchical mesostructured materials. Such advancements in structural biopolymers fabrication provide the basis for engineering a new generation of technical materials that can be interfaced with food and plants.

In this study, a new edible coating material with enhanced mechanical and gas barrier properties was studied by coupling silk fibroin (SF) with poly(vinyl alcohol) (PVOH). SF and PVOH water suspens...

Significance In a world that strives to accommodate population growth and climate pattern changes, there is a compelling need to develop new technologies to enhance agricultural output while minimizing inputs and mitigating their effects on the environment. In this study, we describe a biomaterial-based approach to engineer the microenvironment of seeds through the preservation and delivery of plant growth promoting rhizobacteria (PGPRs) that are able to fix nitrogen and mitigate soil salinity. PGPRs are encapsulated in silk–trehalose (ST) coatings that achieve bacterial preservation and delivery upon sowing. The biomaterial choice is inspired by a recent finding that a combination of proteins and disaccharides is key for anhydrobiosis. This simple technology is effective to boost seed germination and mitigate soil salinity., Human population growth, soil degradation, and agrochemical misuse are significant challenges that agriculture must face in the upcoming decades as it pertains to global food production. Seed enhancement technologies will play a pivotal role in supporting food security by enabling germination of seeds in degraded environments, reducing seed germination time, and boosting crop yields. So far, a great effort has been pursued in designing plants that can adapt to different environments and germinate in the presence of abiotic stressors, such as soil salinity, heat, and drought. The technology proposed here seeks a different goal: To engineer the microenvironment of seeds by encapsulation, preservation, and precise delivery of biofertilizers that can boost seed germination and mitigate abiotic stressors. In particular, we developed a biomaterial based on silk fibroin (S) and trehalose that can be mixed with rhizobacteria and applied on the surface of seeds, retrofitting currently used techniques for seed coating, i.e., dip coating or spray drying. A micrometer thick transparent robust coating is formed by material assembly. The combination of a polymorphic protein as S and of a disaccharide used by living systems to tolerate abiotic stressors provides a beneficial environment for the survival of nonspore forming rhizobacteria outside the soil and in anhydrous conditions. Using Rhizobium tropici CIAT 899 and Phaseolus vulgaris as working models, we demonstrated that rhizobacteria delivered in the soil after coating dissolution infect seedlings’ roots, form root nodules, enhance yield, boost germination, and mitigate soil salinity.

New systems for agrochemical delivery in plants will foster precise agricultural practices and provide new tools to study plants and design crop traits, as standard spray methods suffer from elevated loss and limited access to remote plant tissues. Silk-based microneedles can circumvent these limitations by deploying a known amount of payloads directly in plants' deep tissues. However, plant response to microneedles' application and microneedles' efficacy in deploying physiologically relevant biomolecules are unknown. Here, we show that gene expression associated with Arabidopsis thaliana wounding response decreases within 24 hours post microneedles' application. Additionally, microinjection of gibberellic acid (GA

Seed priming has been for a long time an efficient application method of biofertilizers and biocontrol agents. Due to the quick degradation of the priming agents, this technique has been limited to specific immediate uses. With the increase of awareness of the importance of sustainable use of biofertilizers, seed coating has presented a competitive advantage regarding its ability to adhere easily to the seed, preserve the inoculant, and decompose in the soil. This study compared primed Phaseolus vulgaris seeds with Rhizobium tropici and trehalose with coated seeds using a silk solution mixed with R. tropici and trehalose. We represented the effect of priming and seed coating on seed germination and the development of seedlings by evaluating physiological and morphological parameters under different salinity levels (0, 20, 50, and 75 mM). Results showed that germination and morphological parameters have been significantly enhanced by applying R. tropici and trehalose. Seedlings of coated seeds show higher root density than the freshly primed seeds and the control. The physiological response has been evaluated through the stomatal conductance, the chlorophyll content, and the total phenolic compounds. The stability of these physiological traits indicated the role of trehalose in the protection of the photosystems of the plant under low and medium salinity levels. R. tropici and trehalose helped the plant mitigate the negative impact of salt stress on all traits. These findings represent an essential contribution to our understanding of stress responses in coated and primed seeds. This knowledge is essential to the design of coating materials optimized for stressed environments. However, further progress in this area of research must anticipate the development of coatings adapted to different stresses using micro and macro elements, bacteria, and fungi with a significant focus on biopolymers for sustainable agriculture and soil microbiome preservation.

Renewable silk-protein technologies promote plant growth and reduce food waste

There is a compelling need across several industries to substitute non-degradable, intentionally added microplastics with biodegradable alternatives. Nonetheless, stringent performance criteria in actives' controlled release and manufacturing at scale of emerging materials hinder the replacement of polymers used for microplastics fabrication with circular ones. Here, the authors demonstrate that active microencapsulation in a structural protein such as silk fibroin can be achieved by modulating protein protonation and chain relaxation at the point of material assembly. Silk fibroin micelles' size is tuned from several to hundreds of nanometers, enabling the manufacturing-by retrofitting spray drying and spray freeze drying techniques-of microcapsules with tunable morphology and structure, that is, hollow-spongy, hollow-smooth, hollow crumpled matrices, and hollow crumpled multi-domain. Microcapsules degradation kinetics and sustained release of soluble and insoluble payloads typically used in cosmetic and agriculture applications are controlled by modulating fibroin's beta-sheet content from 20% to near 40%. Ultraviolet-visible studies indicate that burst release of a commonly used herbicide (i.e., saflufenacil) significantly decreases from 25% to 0.8% via silk fibroin microencapsulation. As a proof-of-concept for agrochemicals applications, a 6-day greenhouse trial demonstrates that saflufenacil delivered on corn plants via silk microcapsules reduces crop injury when compared to the non-encapsulated version.

Silk fibroin from the Bombyx mori caterpillar has been processed into many material forms, with potential applications in areas ranging from optoelectronics to tissue engineering. As a hydrogel, silk fibroin has been engineered as a substrate for the regeneration of soft tissues where hydration and mechanical compatibility are necessary. Current fabrication of silk fibroin hydrogels produces microstructured materials that lack transparency and limits the ability to fully exploit the hydrogel form. Transparency is the main characteristic of some human tissues (e.g., cornea) where silk fibroin in the film format has shown potential as scaffolding material, however, lacking the necessary hydration and successful attachment of cells without biochemical functionalization. Additionally, detection using light is an important method to translate information for instruction, sensing, and visualization of biological entities and light sensitive molecules. Here, we introduce a method for the fabrication of transpare...

High resolution bioimaging is not only critical to the study of cellular structures and processes but it also has important applications in drug delivery and therapeutics. Fluorescent nanodiamonds (NDs) are excellent candidates for long-term bioimaging and tracking of biological structures at the nanoscale. Encapsulating NDs in natural biopolymers like silk fibroin (SF) widens their biomedical applications. Here we report the synthesis, structural and optical characterization of ND incorporated SF nanospheres. The photoluminescence from optical defects within the NDs is found to increase when encapsulated in the SF spheres. The encapsulated NDs are applied in vitro to investigate the intracellular mobility compared to bare NDs. The diffusion rate of encapsulated NDs is shown to improve due to SF coating. These ND-SF spheres are envisioned as highly suitable candidates for bioinjectable imaging and drug release carriers for targeted drug delivery applications.

Current methods to produce silk films include casting and spin coating. Here we introduce a new method for the fabrication of silk films: electrogelation. Through use of a closed-loop anode, films with high surface smoothness and optical transparency are produced. Bending the electrode loop allows films with three-dimensional topologies to be formed, possessing thicknesses capable of descending into the submicron thin film regime.

This study reports on the production and characterization of highly porous (up to 91%) composite foams for potential bone tissue engineering (BTE) applications. A calcium phosphate-based glass particulate (PGP) filler of the formulation 50P2O5-40CaO-10TiO2 mol.%, was incorporated into biodegradable poly(d,l-lactic acid) (PDLLA) at 5, 10, 20, and 30 vol.%. The composites were fabricated by melt compounding (extrusion) and compression molding, and converted into porous structures through solid-state foaming (SSF) using high-pressure gaseous carbon dioxide. The morphological and mechanical properties of neat PDLLA and composites in both nonporous and porous states were examined. Scanning electron microscopy micrographs showed that the PGPs were well dispersed throughout the matrices. The highly porous composite systems exhibited improved compressive strength and Young&rsquo, s modulus (up to &gt, 2-fold) and well-interconnected macropores (up to ~78% open pores at 30 vol.% PGP) compared to those of the neat PDLLA foam. The pore size of the composite foams decreased with increasing PGPs content from an average of 920 &micro, m for neat PDLLA foam to 190 &micro, m for PDLLA-30PGP. Furthermore, the experimental data was in line with the Gibson and Ashby model, and effective microstructural changes were confirmed to occur upon 30 vol.% PGP incorporation. Interestingly, the SSF technique allowed for a high incorporation of bioactive particles (up to 30 vol.%&mdash, equivalent to ~46 wt.%) while maintaining the morphological and mechanical criteria required for BTE scaffolds. Based on the results, the SSF technique can offer more advantages and flexibility for designing composite foams with tunable characteristics compared to other methods used for the fabrication of BTE scaffolds.

The precise deployment of functional payloads to plant tissues is a new approach to help advance the fundamental understanding of plant biology and accelerate plant engineering. Here, the design of a silk‐based biomaterial is reported to fabricate a microneedle‐like device, dubbed “phytoinjector,” capable of delivering a variety of payloads ranging from small molecules to large proteins into specific loci of various plant tissues. It is shown that phytoinjector can be used to deliver payloads into plant vasculature to study material transport in xylem and phloem and to perform complex biochemical reactions in situ. In another application, it is demonstrated Agrobacterium‐mediated gene transfer to shoot apical meristem (SAM) and leaves at various stages of growth. Tuning of the material composition enables the fabrication of another device, dubbed “phytosampler,” which is used to precisely sample plant sap. The design of plant‐specific biomaterials to fabricate devices for drug delivery in planta opens new avenues to enhance plant resistance to biotic and abiotic stresses, provides new tools for diagnostics, and enables new opportunities in plant engineering., A silk‐based biomaterial is designed to fabricate a microneedle‐like device with controlled degradation rate in planta via tuning material composition. The device enables precise access to xylem, phloem, and other plant tissues, thus being capable of serving as a delivery tool to release cargo molecules and as a sampling tool for analysis of plants fluid.

This study reports on the production and characterization of highly porous (up to 91%) composite foams for potential bone tissue engineering (BTE) applications. A calcium phosphate-based glass particulate (PGP) filler of the formulation 50P2O5-40CaO-10TiO2 mol.%, was incorporated into biodegradable poly(d,l-lactic acid) (PDLLA) at 5, 10, 20, and 30 vol.%. The composites were fabricated by melt compounding (extrusion) and compression molding, and converted into porous structures through solid-state foaming (SSF) using high-pressure gaseous carbon dioxide. The morphological and mechanical properties of neat PDLLA and composites in both nonporous and porous states were examined. Scanning electron microscopy micrographs showed that the PGPs were well dispersed throughout the matrices. The highly porous composite systems exhibited improved compressive strength and Young’s modulus (up to >2-fold) and well-interconnected macropores (up to ~78% open pores at 30 vol.% PGP) compared to those of the neat PDLLA foam. The pore size of the composite foams decreased with increasing PGPs content from an average of 920 µm for neat PDLLA foam to 190 µm for PDLLA-30PGP. Furthermore, the experimental data was in line with the Gibson and Ashby model, and effective microstructural changes were confirmed to occur upon 30 vol.% PGP incorporation. Interestingly, the SSF technique allowed for a high incorporation of bioactive particles (up to 30 vol.%—equivalent to ~46 wt.%) while maintaining the morphological and mechanical criteria required for BTE scaffolds. Based on the results, the SSF technique can offer more advantages and flexibility for designing composite foams with tunable characteristics compared to other methods used for the fabrication of BTE scaffolds.

We report an artificial intelligence (AI) based method to predict the molecular structure of proteins, focused here on an important subclass of proteins dominated by alpha-helix secondary structure, as found in many structural biomaterials such as keratin and membrane proteins. Fast yet accurate predictions of an unknown protein’s 3D all-atom structure can yield a pre-screened set of candidate proteins to be investigated further via large-scale protein expression in bacteria or yeast. However, classical molecular simulations are greatly limited by the time scale and significant computational cost needed for the complete folding of a long peptide into a complex structure from scratch, which can easily exceed the capability of a supercomputer. To accelerate simulations at low computational cost here we report an innovative machine learning method to offer a high-throughput prediction of the protein structure, as well as the material and biological functions from purely the protein sequences. To achieve this, we designed a novel Multi-scale Neighborhood-based Neural Network (MNNN) model that is capable of learning the neighborhood structured information in the raw protein sequence trained on the database of over 120,000 protein structures. The method directly predicts the phi-psi dihedral angles of the backbone of each constituting amino acid, which is then used to construct the full all-atom 3D structure of the corresponding protein without any template or co-evolutional information. We find that our machine learning model can accurately predict all dihedral angles of any target sequence. The prediction yields a maximum average error of 2.1 A of the predicted 3D structure compared with experimental measurement. We find that the predicted folded structure from MNNN consumes less than six orders of magnitude time than classical molecular dynamics simulations, offering extremely fast folding predictions. Our results suggest that the MNNN model can be used to greatly accelerate the prediction of protein structures.

We report simple, water-based fabrication methods based on protein self-assembly to generate 3D silk fibroin bulk materials that can be easily hybridized with water-soluble molecules to obtain multiple solid formats with predesigned functions. Controlling self-assembly leads to robust, machinable formats that exhibit thermoplastic behavior consenting material reshaping at the nanoscale, microscale, and macroscale. We illustrate the versatility of the approach by realizing demonstrator devices where large silk monoliths can be generated, polished, and reshaped into functional mechanical components that can be nanopatterned, embed optical function, heated on demand in response to infrared light, or can visualize mechanical failure through colorimetric chemistries embedded in the assembled (bulk) protein matrix. Finally, we show an enzyme-loaded solid mechanical part, illustrating the ability to incorporate biological function within the bulk material with possible utility for sustained release in robust, programmably shapeable mechanical formats.

Additive manufacturing (AM) techniques have gained interest in the tissue engineering field thanks to their versatility and unique possibilities of producing constructs with complex macroscopic geometries and defined patterns. Recently, composite materials - namely heterogeneous biomaterials identified as continuous phase (matrix) and reinforcement (filler) - have been proposed as inks that can be processed by AM to obtain scaffolds with improved biomimetic and bioactive properties. Significant efforts have been dedicated to hydroxyapatite (HA)-reinforced composites, especially targeting bone tissue engineering, thanks to the chemical similarities of HA with respect to mineral components of native mineralized tissues. Here we review applications of AM techniques to process HA-reinforced composites and biocomposites for the production of scaffolds with biological matrices, including cellular tissues. The primary outcomes of recent investigations in terms of morphological, structural, and in vitro and in vivo biological properties of the materials are discussed. We classify the approaches based on the nature of the matrices employed to embed the HA reinforcements and produce the tissue substitutes and report a critical discussion on the presented state of the art as well as the future perspectives, to offer a comprehensive picture of the strategies investigated as well as challenges in this emerging field.

Soil sensors and plant wearables play a critical role in smart and precision agriculture via monitoring real-time physical and chemical signals in the soil, such as temperature, moisture, pH, and pollutants and providing key information to optimize crop growth circumstances, fight against biotic and abiotic stresses, and enhance crop yields. Herein, the recent advances of the important soil sensors in agricultural applications, including temperature sensors, moisture sensors, organic matter compounds sensors, pH sensors, insect/pest sensors, and soil pollutant sensors are reviewed. Major sensing technologies, designs, performance, and pros and cons of each sensor category are highlighted. Emerging technologies such as plant wearables and wireless sensor networks are also discussed in terms of their applications in precision agriculture. The research directions and challenges of soil sensors and intelligent agriculture are finally presented.

Chloroplasts extracted from spinach leaves were entrapped in B. mori silk fibroin films to investigate the maintenance of their photosynthetic activity in a dry environment. Chloroplast stability was studied under various storage conditions (different temperature and light cycles) using electron microscopy, spectroscopic analysis and measuring of their photosynthetic activity (i.e. oxygen production). When compared to other environments previously investigated, silk fibroin films enhanced the preservation of the chloroplasts' photosynthetic activity.

We report that pure silk fibroin can be a green and biofunctional photoresist for deep ultraviolet photolithography. All processes are entirely water-based, from resist solvent to resist removal, and rely on the phototendering effect that decreases the crystallinity of silk fibroin films by DUV exposure. Additionally, the potential decrease in activity of bio-dopants due to high-energy irradiation is irrelevant to our positive-tone lithographic method.

Recent use of biopolymers as interface materials between planar, inorganic electronics and biological tissues has required the adaptation of micro- and nanofabrication techniques for use with these nontraditional materials. In this work, a method which builds on this principle for spatial control of adhesion in multilayer silk fibroin laminates is investigated. This is accomplished through the addition of a spatially patterned amorphous silk adhesive layer in between the films to be adhered, before thermally processing them with heat (120 °C) and pressure (80 Psi) according to established procedures. A one-step method for rapid, high-throughput fabrication is demonstrated, which establishes a strong (1100 kPa) bond between the layers independent of the initial processing conditions of the films. The adhesive layers can be patterned using existing silk fabrication techniques, allowing for the assembly of complex geometries including bilayers and microbubbles. Additionally, the utility of this method is demonstrated for potential applications in drug delivery and transient electronics. This approach provides a versatile method for construction of complex multilayer structures in silk, which with future work may ultimately improve the utility of this material as a bridge between high technology and the biomedical sciences.

Type I collagen is a major structural and functional protein in connective tissues. However, collagen gels exhibit unstable geometrical properties, arising from extensive cell-mediated contraction. In an effort to stabilize collagen-based hydrogels, plastic compression was used to hybridize dense collagen (DC) with electrospun silk fibroin (SF) mats, generating multilayered DC-SF-DC constructs. Seeded mesenchymal stem cell (MSC)-mediated DC-SF-DC contraction, as well as growth and differentiation under chondrogenic and osteogenic supplements, were compared to those seeded in DC and on SF alone. The incorporation of SF within DC prevented extensive cell-mediated collagen gel contraction. The effect of the multilayered hybrid on MSC remodelling capacity was also evident at the transcription level, where the expression of matrix metalloproteinases and their inhibitor (MMP1, MMP2, MMP3, MMP13 and Timp1) by MSCs within DC-SF-DC were comparable to those on SF and significantly downregulated in comparison to DC, except for Timp1. Chondrogenic supplements stimulated extracellular matrix production within the construct, stabilizing its multilayered structure and promoting MSC chondrogenic differentiation, as indicated by the upregulation of the genes Col2a1 and Agg and the production of collagen type II. In osteogenic medium there was an upregulation in ALP and OP along with the presence of an apatitic phase, indicating MSC osteoblastic differentiation and matrix mineralization. In sum, these results have implications on the modulation of three-dimensional collagen-based gel structural stability and on the stimulation and maintenance of the MSC committed phenotype inherent to the in vitro formation of chondral tissue and bone, as well as on potential multilayered complex tissues. Copyright © 2015 John Wiley & Sons, Ltd.

Food quality monitoring, particularly, the detection of bacterial pathogens and spoilage throughout the food supply chain, is critical to ensure global food safety and minimize food loss. Incorporating sensors into packaging is promising, but it is challenging to achieve the required sampling volume while using food‐safe sensor materials. Here, by leveraging water‐based processing of silk fibroin, a platform for the detection of pathogenic bacteria in food is realized using a porous silk microneedle array; the microneedle array samples fluid from the interior of the food by capillary action, presenting the fluid to polydiacetylene‐based bioinks printed on the backside of the array. Through the colorimetric response of bioink patterns, Escherichia coli contamination in fish fillets is identified within 16 h of needle injection. This response is distinct from spoilage measured via the increase in sample pH. It is also shown that the microneedles can pierce commercial food packaging, and subsequently sample fluid and present it to the sensor, enabling the adaptation of the technology downstream in food supply chains such as in stores or at home. This study highlights that regenerated structural biopolymers can serve as safe materials for food contact and sensing with robust mechanical properties and tailored chemistry.

In article number 1903551, Benedetto Marelli and co‐workers design a silk‐based biomaterial to fabricate a microneedle‐like device with controlled degradation rate in planta via tuning material composition. The device enables precise access to xylem, phloem, and other plant tissues, thus being capable of serving as a delivery tool to release cargo molecules and as a sampling tool for analysis of plants fluid. [Image: see text]

When adipose tissue (AT) is impaired by trauma or disease, AT engineering could provide a shelf-ready structural and functional restoration as alternative to current clinical treatments, which mainly aim at aesthetic replacement. Yet, the lack of an efficient vascular network within the scaffolds represents a major limitation to their translation application in patients. Here, we propose the use of microstructured crosslinked gelatin hydrogels with an embedded prevascular channel as scaffolding materials for AT engineering. The scaffolds are fabricated using – simultaneously – alginate-based microbeads and 3D printed filaments as sacrificial material encapsulated in gelatin at the point of material fabrication and removed post-crosslinking. This method yields the formation of microstructures that resemble the micro-architecture of physiological human fat tissue and of microvessels that can facilitate vascularization through anastomosis with patients’ own blood vessels. The cytocompatible method used to prepare the gelatin scaffolds showed structural stability over time while allowing for cell infiltration and protease-based remodeling/degradation. Scaffolds’ mechanical properties were also designed to mimic the one of natural breast adipose tissue, a key parameter for AT regeneration. Scaffold’s embedded channel (∅ = 300–400 µm) allowed for cell infiltration and enabled blood flow in vitro when an anastomosis with a rat blood artery was performed using surgical glue. In vitro tests with human mesenchymal stem cells (hMSC) showed colonization of the porous structure of the gelatin hydrogels, differentiation into adipocytes and accumulation of lipid droplets, as shown by Oil Red O staining. Statement of Significance The potential clinical use of scaffolds for adipose tissue (AT) regeneration is currently limited by an unmet simultaneous achievement of adequate structural/morphological properties together with a promoted scaffold vascularization. Sacrificial materials, currently used either to obtain a tissue-mimicking structure or hollow channels to promote scaffold’ vascularization, are powerful versatile tools for the fabrication of scaffolds with desired features. However, an integrated approach by means of sacrificial templates aiming at simultaneously achieving an adequate AT-mimicking structure and hollow channels for vascularization is missing. Here, we prove the suitability of crosslinked gelatin scaffolds obtained by using sacrificial alginate microbeads and 3D printed strands to achieve proper features and hollow channels useful for scaffolds vascularization.

Light-induced material phase transitions enable the formation of shapes and patterns from the nano- to the macroscale. From lithographic techniques that enable high-density silicon circuit integration, to laser cutting and welding, light-matter interactions are pervasive in everyday materials fabrication and transformation. These noncontact patterning techniques are ideally suited to reshape soft materials of biological relevance. We present here the use of relatively low-energy (< 2 nJ) ultrafast laser pulses to generate 2D and 3D multiscale patterns in soft silk protein hydrogels without exogenous or chemical cross-linkers. We find that high-resolution features can be generated within bulk hydrogels through nearly 1 cm of material, which is 1.5 orders of magnitude deeper than other biocompatible materials. Examples illustrating the materials, results, and the performance of the machined geometries in vitro and in vivo are presented to demonstrate the versatility of the approach.

A formulation of regenerated silk fibroin solution that can be easily functionalized and inkjet printed on numerous surfaces is developed. As an example, the inks can be printed on laboratory gloves that change color when exposed to bacteria.

We demonstrate that intrafibrillar, homogenous collagen biomineralization can be achieved by controlling self-assembly under mildly alkaline conditions. Using dense collagen (DC) gels as an osteoid model, we modulated their fibrillogenesis environment to evaluate the effects of fibrillogenesis pH on the protein charge distribution and ultimately on biomineralization. Cationic and anionic dye staining and electron cryomicroscopy analyses established that fibrillogenesis under mildly alkaline conditions promotes the formation of electronegative charges within the protein (anionic DC gels). These charges are stable upon titration of the gel pH to physiological values. Subsequent exposure of anionic DC gels to simulated body fluid induced the intrafibrillar biomineralization of the gels, promoting a rapid, extensive formation of carbonated hydroxyapatite, and strongly impacting gel mechanical properties. The generality and significance of this approach has been addressed by implanting freshly made anionic DC gels in vivo, in a rat subcutaneous model. Subcutaneous implants showed an extensive, homogenous biomineralization as early as at day 7, indicating that anionic collagen gels rapidly self-mineralize upon contact with body fluids in a non-osseous implantation site. The control of collagen fibrillogenesis pH provides not only new interpretations to what has been called the collagen mineralization enigma by demonstrating that neat collagen can intrafibrilarly self-mineralize, but it will also set a new starting point for the use of DC gels in bone regenerative medicine, in addition as potential applications as mineralized tissue model or as slow-release delivery carriers.

Carbonic anhydrase was entrapped in a matrix of ultrasonically bonded hydroxyapatite microparticles coated with β-sheet structured silk fibroin. Transfer of the reactant and product between the enzyme and the assembly surface was evident and the system showed a remarkable operational, storage and thermal stability, with enzymatic activity almost unchanged after a one hour's treatment at 110 °C and the assembly retained 45% of its initial activity after 3 weeks of continuous heating at 80 °C in an amine solution. This thermal stability was excellent compared with described CA immobilization systems and indicates that silk fibroin may limit thermally induced enzyme conformation changes and prevent desorption.