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Rapid deployment of automation in today's world has opened up exciting possibilities in the realm of design and fabrication of soft robotic grippers endowed with sensing capabilities. Herein, a novel design and rapid fabrication by 3D printing of a mechano‐optic force sensor with a large dynamic range, sensitivity, and linear response, enabled by metamaterials‐based structures, is presented. A simple approach for programming the metamaterial's behavior based on mathematical modeling of the sensor under dynamic loading is proposed. Machine learning models are utilized to predict the complete force–deformation profile, encompassing the linear range, the onset of nonlinear behavior, and the slope of profiles in both bending and compression‐dominated regions. The design supports seamless integration of the sensor into soft grippers, enabling 3D printing of the soft gripper with an embedded sensor in a single step, thus overcoming the tedious and complex and multiple fabrication steps commonly applied in conventional processes. The sensor boasts a fine resolution of 0.015 N, a measurement range up to 16 N, linearity (adj. R2–0.991), and delivers consistent performance beyond 100 000 cycles. The sensitivity and range of the embedded mechano‐optic force sensor can be easily programmed by both the metamaterial structure and the material's properties.

Abstract Additive manufacturing technologies based on stereolithography rely on initiating spatial photopolymerization by using photoinitiators activated by UV-visible light. Many applications requiring printing in water are limited since water-soluble photoinitiators are scarce, and their price is skyrocketing. On the contrary, thermal initiators are widely used in the chemical industry for polymerization processes due to their low cost and simplicity of initiation by heat at low temperatures. However, such initiators were never used in 3D printing technologies, such as vat photopolymerization stereolithography, since localizing the heat at specific printing voxels is impossible. Here we propose using a thermal initiator for 3D printing for localized polymerization processes by near-infrared and visible light irradiation without conventional photoinitiators. This is enabled by using gold nanorods or silver nanoparticles at very low concentrations as photothermal converters in aqueous and non-aqueous mediums. Our proof of concept demonstrates the fabrication of hydrogel and polymeric objects using stereolithography-based 3D printers, vat photopolymerization, and two-photon printing.

Traditional printing compositions for stereolithography (SLA), a vat photopolymerization technology, rely on light-sensitive photoinitiators (PIs) to initiate cross-linking reactions. Here, we propose a new approach for printing in which the polymerisation occurs locally with carbon nanotubes (CNTs), which function as photothermal converters combined with low-cost thermal initiators (TIs). The irradiation is performed at near-infrared (NIR), which enables deep light penetration, and polymerisation in black compositions, thus increasing the printing throughput. We demonstrate the control over polymerisation kinetics, printing resolution and cure depth, achieving very large printable layer thickness. The CNT photoconvertors can be used in both nonaqueous and aqueous systems, while the latter addresses the limited availability of water-soluble PIs for printing in water. The CNT enables dual use, initiating polymerisation and printing composite materials. This approach presents an advancement in SLA-based technologies, avoiding the use of conventional PIs and thus broadening the scope of 3D printing applications.

Soft grippers are garnering increasing attention for their adeptness in conforming to diverse objects, particularly delicate items, without warranting precise force control. This attribute proves especially beneficial in unstructured environments and dynamic tasks such as food handling. Human hands, owing to their elevated dexterity and precise motor control, exhibit the ability to delicately manipulate complex food items, such as small or fragile objects, by dynamically adjusting their grasping configurations. Furthermore, with their rich sensory receptors and hand-eye coordination that provide valuable information involving the texture and form factor, real-time adjustments to avoid damage or spill during food handling appear seamless. Despite numerous endeavors to replicate these capabilities through robotic solutions involving soft grippers, matching human performance remains a formidable engineering challenge. Robotic competitions serve as an invaluable platform for pushing the boundaries of manipulation capabilities, simultaneously offering insights into the adoption of these solutions across diverse domains, including food handling. Serving as a proxy for the future transition of robotic solutions from the laboratory to the market, these competitions simulate real-world challenges. Since 2021, our research group has actively participated in RoboSoft competitions, securing victories in the Manipulation track in 2022 and 2023. Our success was propelled by the utilization of a modified iteration of our Retractable Nails Soft Gripper (RNSG), tailored to meet the specific requirements of each task. The integration of sensors and collaborative manipulators further enhanced the gripper’s performance, facilitating the seamless execution of complex grasping tasks associated with food handling. This article encapsulates the experiential insights gained during the application of our highly versatile soft gripper in these competition environments.

Abstract Fabrication of glass with complex geocd the low resolution of particle‐based or fused glass technologies. Herein, a high‐resolution 3D printing of transparent nanoporous glass is presented, by the combination of transparent photo‐curable sol–gel printing compositions and digital light processing (DLP) technology. Multi‐component glass, including binary (Al2O3‐SiO2), ternary (ZnO‐Al2O3‐SiO2, TiO2‐Al2O3‐SiO2), and quaternary oxide (CaO‐P2O5‐Al2O3‐SiO2) nanoporous glass objects with complex shapes, high spatial resolutions, and multi‐oxide chemical compositions are fabricated, by DLP printing and subsequent sintering process. The uniform nanopores of Al2O3‐SiO2‐based nanoporous glasses with the diameter (≈6.04 nm), which is much smaller than the visible light wavelength, result in high transmittance (>95%) at the visible range. The high surface area of printed glass objectives allows post‐functionalization via the adsorption of functional guest molecules. The photoluminescence and hydrophobic modification of 3D printed glass objectives are successfully demonstrated. This work extends the scope of 3D printing to transparent nanoporous glasses with complex geometry and facile functionalization, making them available for a wide range of applications.

Abstract Although natural continuum structures, such as the boneless elephant trunk, provide inspiration for new versatile grippers, highly deformable, jointless, and multidimensional actuation has still not been achieved. The challenging pivotal requisites are to avoid sudden changes in stiffness, combined with the capability of providing reliable large deformations in different directions. This research addresses these two challenges by harnessing porosity at two levels: material and design. Based on the extraordinary extensibility and compressibility of volumetrically tessellated structures with microporous elastic polymer walls, monolithic soft actuators are fabricated by 3D printing unique polymerizable emulsions. The resulting monolithic pneumatic actuators are printed in a single process and are capable of bidirectional movements with just one actuation source. The proposed approach is demonstrated by two proof‐of‐concepts: a three‐fingered gripper, and the first ever soft continuum actuator that encodes biaxial motion and bidirectional bending. The results open up new design paradigms for continuum soft robots with bioinspired behavior based on reliable and robust multidimensional motions.

We present a methodology for a high-throughput screening (HTS) of transcription factor libraries, based on bacterial cells and GFP fluorescence. The method is demonstrated on the Escherichia coli LysR-type transcriptional regulator YhaJ, a key element in 2,4-dinitrotuluene (DNT) detection by bacterial explosives’ sensor strains. Enhancing the performance characteristics of the YhaJ transcription factor is essential for future standoff detection of buried landmines. However, conventional directed evolution methods for modifying YhaJ are limited in scope, due to the vast sequence space and the absence of efficient screening methods to select optimal transcription factor mutants. To overcome this limitation, we have constructed a focused saturation library of ca. 6.4 × 107 yhaJ variants, and have screened over 70 % of its sequence space using fluorescence-activated cell sorting (FACS). Through this screening process, we have identified YhaJ mutants exhibiting superior fluorescence responses to DNT, which were then effectively transformed into a bioluminescence-based DNT detection system. The best modified DNT reporter strain demonstrated a 7-fold lower DNT detection threshold, a 45-fold increased signal intensity, and a 40 % shorter response time compared to the parental bioreporter. The FACS-based HTS approach presented here may hold a potential for future molecular enhancement of other sensing and catalytic bioreactions.

The median survival time of patients with an aggressive brain tumor, glioblastoma, is still poor due to ineffective treatment. The discovery of androgen receptor (AR) expression in 56% of cases offers a potential breakthrough. AR antagonists, including bicalutamide and enzalutamide, induce dose-dependent cell death in glioblastoma and glioblastoma-initiating cell lines (GIC). Oral enzalutamide at 20 mg/kg reduces subcutaneous human glioblastoma xenografts by 72% (p = 0.0027). We aimed to further investigate the efficacy of AR antagonists in intracranial models of human glioblastoma. In U87MG intracranial models, nude mice administered Xtandi (enzalutamide) at 20 mg/kg and 50 mg/kg demonstrated a significant improvement in survival compared to the control group (p = 0.24 and p < 0.001, respectively), confirming a dose–response relationship. Additionally, we developed a newly reformulated version of bicalutamide, named “soluble bicalutamide (Bic-sol)”, with a remarkable 1000-fold increase in solubility. This reformulation significantly enhanced bicalutamide levels within brain tissue, reaching 176% of the control formulation’s area under the curve. In the U87MG intracranial model, both 2 mg/kg and 4 mg/kg of Bic-sol exhibited significant efficacy compared to the vehicle-treated group (p = 0.0177 and p = 0.00364, respectively). Furthermore, combination therapy with 8 mg/kg Bic-sol and Temozolomide (TMZ) demonstrated superior efficacy compared to either Bic-sol or TMZ as monotherapies (p = 0.00706 and p = 0.0184, respectively). In the ZH-161 GIC mouse model, the group treated with 8 mg/kg Bic-sol as monotherapy had a significantly longer lifespan than the groups treated with TMZ or the vehicle (p < 0.001). Our study demonstrated the efficacy of androgen receptor antagonists in extending the lifespan of mice with intracranial human glioblastoma, suggesting a promising approach to enhance patient outcomes in the fight against this challenging disease.

NEMS devices, nano-electro-mechanical systems, by virtue of their minute size, offer ultra-high sensitivity, though at the expense of manufacturing complexity. Here, Stassi et al succeed in manufacturing high quality factor NEMS devices using high resolution 3D printing.

UV-curable particle-free ceramic compositions for stereolithography-based 3D printing technologies present a promising alternative to the commonly used particle-based compositions. So far, such compositions were mainly based on solutions of pre-ceramic polymers which limit their applications to silicon-containing materials. However, the application of particle-free inks for the fabrication of other ceramic materials, in particular dense polycrystalline ones, is very little explored. We present a new and general fabrication approach based on all-solution compositions, by combining sol–gel chemistry and photopolymerization, for obtaining dense 3D ceramic structures by DLP printing. The process is demonstrated here for the fabrication of barium titanate (BaTiO3). By using chelating solvent and monomer, a stable UV-curable solution is obtained. An aging period of 8–14 days was crucial for obtaining dense ceramic objects without any secondary phases. The heat treatment was found to affect the microstructure, density and hardness of the resulting ceramics. The presented process enables obtaining objects free of carbon materials, having a density as high as 98% of the theoretical value, and a hardness of 4.3 GPa.

Self-healing hydrogels can mimic the damage repair behaviour of living tissues, but such hydrogels have only been processed via extrusion-based additive manufacturing technology. Here, the authors demonstrate a rapidly self-healing hydrogel which can be processed by DLP printing.

Abstract Localization of rectal tumors is a challenge in minimally invasive surgery due to the lack of tactile sensation. We had developed liposomal indocyanine green (Lip-ICG) for localization of rectal tumor. In this study we evaluated the effects of liposome size and lipid PEGylation on imaging. We used an endoscopically-guided orthotopic experimental rectal cancer model in which tumor fluorescence was determined at different time points after intravenous (i.v.) administration of Lip-ICG and PEGylated liposomes (PEG-Lip-ICG). Signal intensity was measured by tumor-to-background ratio (TBR), or normalized TBR (compared to TBR of free ICG). Fluorescence microscopy of tumor tissue was performed to determine fluorescence localization within the tissue and blood vessels. Liposomes of 60 nm showed an increased TBR compared with free ICG at 12 hours after i.v. injection: normalized TBR (nTBR) = 3.11 vs. 1, respectively (p = 0.006). Larger liposomes (100 nm and 140 nm) had comparable signal to free ICG (nTBR = 0.98 ± 0.02 and 0.78 ± 0.08, respectively), even when additional time points were examined (0.5, 3 and 24 hours). PEG-Lip- ICG were more efficient than Lip-ICG (TBR = 4.2 ± 0.18 vs. 2.5 ± 0.12, p

Effective management of heat transfer, such as conduction and radiation, through glass windows is one of the most challenging issues in smart window technology. In this work, reduced Graphene Oxide (rGO) thin films of varying thicknesses are fabricated onto Fluorine-doped Tin Oxide (FTO) glass via electrophoretic deposition technique. The sample thicknesses increase with increasing number of deposition cycles (5, 10, 20 cycles). It is hypothesized that such rGO thin films, which are well-known for their high thermal conductivities, can conduct heat away laterally towards heat sinks and reduce near-infrared (NIR) transmittance through them, thus effectively slowing down the temperature increment indoors. The performance of rGO/FTO in reducing indoor temperatures is investigated with a solar simulator and a UV-Vis-NIR spectrophotometer. The 20-cycles rGO thin films showed 30% more NIR blocked at 1000 nm as compared to clean FTO, as well as the least temperature increment of 0.57 °C following 30 min of solar irradiation. Furthermore, the visible transmittance of the as-fabricated rGO films remain on par with commercial solar films, enabling up to 60% of visible light transmittance for optimal balance of transparency and heat reduction. These results suggest that the rGO thin films have great potential in blocking heat transfer and are highly recommended for smart window applications. Keywords: Electrophoretic deposition, Reduced graphene oxide, Thin films, Heat conduction, Smart windows

Wood warping is a phenomenon known as a deformation in wood that occurs when changes in moisture content cause an unevenly volumetric change due to fiber orientation. Here we present an investigation of wood warped objects that were fabricated by 3D printing. Similar to natural wood warping, water evaporation causes volume decrease of the printed object, but in contrast, the printing pathway pattern and flow rate dictate the direction of the alignment and its intensity, all of which can be predesigned and affect the resulting structure after drying. The fabrication of the objects was performed by an extrusion-based 3D printing technique that enables the deposition of water-based inks into 3D objects. The printing ink was composed of 100% wood-based materials, wood flour, and plant-extracted natural binders cellulose nanocrystals, and xyloglucan, without the need for any additional synthetic resins. Two archetypal structures were printed: cylindrical structure and helices. In the former, we identified a new length scale that gauges the effect of gravity on the shape. In the latter, the structure exhibited a shape transition analogous to the opening of a seedpod, quantitatively reproducing theoretical predictions. Together, by carefully tuning the flow rate and printing pathway, the morphology of the fully dried wooden objects can be controlled. Hence, it is possible to design the printing of wet objects that will form different final 3D structures.

We have shown previously that Nano-PSO, a nanodroplet formulation of pomegranate seed oil, delayed progression of neurodegeneration signs when administered for a designated period of time to TgMHu2ME199K mice, modeling for genetic prion disease. In the present work, we treated these mice with a self-emulsion formulation of Nano-PSO or a parallel Soybean oil formulation from their day of birth until a terminal disease stage. We found that long term Nano-PSO administration resulted in increased survival of TgMHu2ME199K lines by several months. Interestingly, initiation of treatment at day 1 had no clinical advantage over initiation at day 70, however cessation of treatment at 9 months of age resulted in the rapid loss of the beneficial clinical effect. Pathological studies revealed that treatment with Nano-PSO resulted in the reduction of GAG accumulation and lipid oxidation, indicating a strong neuroprotective effect. Contrarily, the clinical effect of Nano-PSO did not correlate with reduction in the levels of disease related PrP, the main prion marker. We conclude that long term administration of Nano-PSO is safe and may be effective in the prevention/delay of onset of neurodegenerative conditions such as genetic CJD.

Second skin is a topically applied, skin-conforming material that mimics human skin properties and bears potential cosmetic and e-skin applications. To successfully integrate with natural skin, characteristics such as color and skin features must be matched. In this work, we prepared bio-based skin-like films from cross-linked keratin/melanin films (KMFs), using a simple fabrication method and non-toxic materials. The films retained their stability in aqueous solutions, showed skin-like mechanical properties, and were homogenous and handleable, with non-granular surfaces and a notable cross-linked structure as determined by attenuated total reflection (ATR). In addition, the combination of keratin and melanin allowed for adjustable tones similar to those of natural human skin. Furthermore, KMFs showed light transmittance and UV-blocking (up to 99%) as a function of melanin content. Finally, keratin/melanin ink (KMI) was used to inkjet-print high-resolution images with natural skin pigmented features. The KMFs and KMI may offer advanced solutions as e-skin or cosmetics platforms.

With the rapid development of wearable electronic systems, the need for stretchable nanogenerators becomes increasingly important for autonomous applications such as the Internet-of-Things. Piezoelectric nanogenerators are of interest for their ability to harvest mechanical energy from the environment with its inherent polarization arising from crystal structures or molecular arrangements of the piezoelectric materials. In this work, 3D printing is used to fabricate a stretchable piezoelectric nanogenerator which can serve as a self-powered sensor based on synthesized oxide–polymer composites.

Three-dimensional (3D) printing has recently been introduced into the field of chemistry as an enabling tool employed to perform reactions, but so far, its use has been limited due to material and structural constraints. We have developed a new approach for fabricating 3D catalysts with high-complexity features for chemical reactions via digital light processing printing (DLP). PtO2-WO3 heterogeneous catalysts with complex shapes were directly fabricated from a clear solution, composed of photo-curable organic monomers, photoinitiators, and metallic salts. The 3D-printed catalysts were tested for the hydrogenation of alkynes and nitrobenzene, and displayed excellent reactivity in these catalytic transformations. Furthermore, to demonstrate the versatility of this approach and prove the concept of multifunctional reactors, a tungsten oxide-based tube consisting of three orderly sections containing platinum, rhodium, and palladium was 3D printed.

Shape memory polymers are attractive smart materials that have many practical applications and academic interest. Three-dimensional (3D) printable shape memory polymers are of great importance for the fabrication of soft robotic devices due to their ability to build complex 3D structures with desired shapes. We present a 3D printable shape memory polymer, with controlled melting and transition temperature, composed of methacrylated polycaprolactone monomers and N-Vinylcaprolactam reactive diluent. Tuning the ratio between the monomers and the diluents resulted in changes in melting and transition temperatures by 20, and 6 °C, respectively. The effect of the diluent addition on the shape memory behavior and mechanical properties was studied, showing above 85% recovery ratio, and above 90% fixity, when the concentration of the diluent was up to 40 wt %. Finally, we demonstrated multi-material printing of a 3D structure that can be activated locally, at two different temperatures, by two different stimuli; direct heating and light irradiation. The remote light activation was enabled by utilizing a coating of Carbon Nano Tubes (CNTs) as an absorbing material, onto sections of the printed objects.

Titanium(IV) complexes exhibit high potential as anti-tumor agents, particularly due to their low intrinsic toxicity and cytotoxicity toward cisplatin resistant cells. Nevertheless, Ti(IV) complexes generally undergo rapid hydrolysis that previously hampered their utilization as anticancer drugs. We recently overcame this difficulty by developing a highly stable Ti(IV) complex that is based on tetra-phenolato, hexadentate ligand, formulated into organic nanoparticles. Herein we investigated the activity of this complex in vitro and in vivo. Although inactive when tested directly due to poor solubility, when formulated, this complex displayed (a) high cytotoxicity toward cisplatin resistant human ovarian cells, A2780-cp, with resistance factor of 1.1; (b) additive behavior in combination with cisplatin toward ovarian and colon cancer cells; (c) selectivity toward cancer cells as implied by its mild activity toward non-cancerous, fibroblast lung cells, MRC-5; (d) high stability and durability as manifested by the ability to maintain cytotoxicity, even following one week of incubation in 100% aquatic medium solution; and (e) in vivo efficacy toward solid tumors of human colon cancer cells, HT-29, in nude mice without any clinical signs of toxicity. These features support the formulated phenolato Ti(IV) complex being an effective and selective anti-tumoral agent.

Aerogel objects inspired by plant cell wall components and structures were fabricated using extrusion-based 3D printing at cryogenic temperatures. The printing process combines 3D printing with the alignment of rod-shaped nanoparticles through the freeze-casting of aqueous inks. We have named this method direct cryo writing (DCW) as it encompasses in a single processing step traditional directional freeze casting and the spatial fidelity of 3D printing. DCW is demonstrated with inks that are composed of an aqueous mixture of cellulose nanocrystals (CNCs) and xyloglucan (XG), which are the major building blocks of plant cell walls. Rapid fixation of the inks is achieved through tailored rheological properties and controlled directional freezing. Morphological evaluation revealed the role of ice crystal growth in the alignment of CNCs and XG. The structure of the aerogels changed from organized and tubular to disordered and flakey pores with an increase in XG content. The internal structure of the printed objects mimics the structure of various wood species and can therefore be used to create wood-like structures via additive manufacturing technologies using only renewable wood-based materials.

In the past few years, the synthesis of Cu nanoparticles has attracted much attention because of its huge potential for replacing expensive nano silver inks utilized in conductive printing. A major problem in utilizing these copper nanoparticles is their inherent tendency to oxidize in ambient conditions. Recently, there have been several reports presenting various approaches which demonstrate that copper nanoparticles can resist oxidation under ambient conditions, if they are coated by a proper protective layer. This layer may consist of an organic polymer, alkene chains, amorphous carbon or graphenes, or inorganic materials such as silica, or an inert metal. Such coated copper nanoparticles enable achieving high conductivities by direct printing of conductive patterns. These approaches open new possibilities in printed electronics, for example by using copper based inkjet inks to form various devices such as solar cells, Radio Frequency Identification (RFID) tags, and electroluminescence devices. This paper provides a review on the synthesis of copper nanoparticles, mainly by wet chemistry routes, and their utilization in printed electronics.