3D Bioplotter Research Papers

Polarized THz time domain spectroscopy was used to study the anisotropic properties of wood-based materials for potential optical elements in the THz range, such as half-wave and quarter-wave plates. Wood samples of different species and sample thickness were studied experimentally showing high birefringence but rather high absorption. We elaborate on two approaches to optimize the optical properties for use as wave plates and assess them based on a figure of merit describing their efficiency as a function of birefringence and absorption. The first approach is to dry the wood samples, which significantly improves the efficiency of wave plates. The second…

Geraniaceae seeds represent a role model in soft robotics thanks to their ability to move autonomously across and into the soil driven by humidity changes. The secret behind their mobility and adaptivity is embodied in the hierarchical structures and anatomical features of the biological hygroscopic tissues, geometrically designed to be selectively responsive to environmental humidity. Following a bioinspired approach, the internal structure and biomechanics of Pelargonium appendiculatum (L.f.) Willd seeds are investigated to develop a model for the design of a soft robot. The authors exploit the re-shaping ability of 4D printed materials to fabricate a seed-like soft robot, according…

Polymer blend system has been commonly applied in a wide variety of applications. Herein, we propose to introduce sugar particles to polymer matrix, which results in a controllable polymer swelling under the action of osmotic pressure upon soaking in water. Taking advantage of this economic and environment-friendly, water-induced polymer swelling process, we have fabricated wrinkled conductive films and 3D structures by depositing conductive materials on the swollen polymer substrates for stretchable strain sensing devices. Several commercial silicone elastomers were utilized in the study. Key processing factors affecting the polymer swelling were investigated, including film thickness, sugar concentration, and temperature of…

As an engineering frontier, highly stretchable sensors are widely applied in many fields, such as human motion detection, personal healthcare monitoring, and human-machine interactions. In this study, novel silver nanowire (AgNW)-based stretchable sensors with hierarchical wrinkled structures were fabricated through a two-step process, namely water-induced swelling and AgNW deposition. As highly soluble additives, sodium chloride particles were incorporated into the elastomer matrix. Upon soaking in dopamine aqueous solution, significant swelling was introduced onto the elastomer substrate. The dopamine deposition is accompanied with the swelling process, which endows the sample surface with ultra-hydrophilicity. Additionally, the dopamine-modified swollen samples “capture” the nanowires…

People with neurological deficits face difficulties perceiving their surroundings, resulting in an urgent need for wearable electronic skin (e-skin) that can monitor external stimuli and temperature changes. However, the monolithic structure of e-skin is not conducive to breathability and hinders hair growth, limiting its wearing comfort. In this work, we prepared fully three-dimensional (3D) printed e-skin that allowed hair penetration and growth. This e-skin also achieved simultaneous pressure and temperature detection and a high tactile resolution of 100 cm–2, which is close to that of human fingertips. The temperature sensor maintained linear measurements within 10–60 °C. The pore microstructure prepared…

Amine-functionalized polymers (AFPs) are able to react with carbon dioxide (CO2) and are therefore useful in CO2 capture and sensing. To develop AFP-based CO2 sensors, it is critical to examine their electrical responses to CO2 over long periods of time, so that the device can be used consistently for measuring CO2 concentration. To this end, we synthesized poly(N-[3-(dimethylamino)propyl] methacrylamide) (pDMAPMAm) by free radical polymerization and tested its ability to behave as a CO2-responsive polymer in a transducer. The electrical response of this polymer to CO2 upon long exposure times was measured in both the aqueous and solid phases. Direct current…

Presented here is the synthesis of a 3D printable nano-polysaccharide self-healing hydrogel for flexible strain sensors. Consisting of three distinct yet complementary dynamic bonds, the crosslinked network comprises imine, hydrogen, and catecholato-metal coordination bonds. Self-healing of the hydrogel is demonstrated by macroscopic observation, rheological recovery, and compression measurements. The hydrogel was produced via imine formation of carboxyl methyl chitosan, oxidized cellulose nanofibers, and chitin nanofibers followed by two subsequent crosslinking stages: immersion in tannic acid (TA) solution to create hydrogen bonds, followed by soaking in FeIII solution to form catecholato-metal coordination bonds between TA and FeIII. The metal coordination bonds…

The capacity for a soft material to combine remote sensing and remote actuation is highly desirable for many applications in soft robotics and wearable technologies. This work presents a silicone elastomer with a suspension of a small weight fraction of ferromagnetic nickel nanorods, which is capable of both sensing deformation and altering stiffness in the presence of an external magnetic field. Cylinders composed of silicone elastomer and 1% by weight nickel nanorods experience large increases in compressive modulus when exposed to an external magnetic field. Incremental compressions totaling 600 g of force applied to the same silicone–nanorod composites increase the…

Emerging technologies such as smart packaging are shifting the requirements on electronic components, notably regarding service life, which counts in days instead of years. As a result, standard materials are often not adapted due to economic, environmental or manufacturing considerations. For instance, the use of metal conductive tracks in disposable electronics is a waste of valuable resources and their accumulation in landfills is an environmental concern. In this work, we report a conductive ink made of carbon particles dispersed in a solution of shellac. This natural and water-insoluble resin works as a binder, favourably replacing petroleum-derived polymers. The carbon particles…

Soft-ionic materials with biocompatibility and 3D printability are needed to develop next-generation devices to interface between electronic and biological signals. Herein, thermoreversible and biocompatible ionic liquid gels or iongels, which can be processed by direct ink writing are reported. The iongels are designed by taking advantage of polyvinyl alcohol/phenol interactions to gelify biocompatible cholinium carboxylate ionic liquids. The obtained iongels are stable, soft, and flexible materials (Young modulus between 14 and 70 kPa) with high ionic conductivity (1.8 × 10–2 S cm–1). Interestingly, they presented thermoreversible properties with gel–sol transitions ranging from 85 and 110 °C, which allows the iongel…

Flexible and stretchable conductors are crucial components for next-generation flexible devices. Wrinkled structures often have been created on such conductors by depositing conductive materials on the pre-stretched or organic solvent swollen samples. Herein, water swelling is first proposed to generate the wrinkled structures on silicone elastomers. By immersing silicone/sugar hybrid in water, a significant amount of swelling occurs as a result of osmosis and capillary interactions with the sugar and silicone matrix. Considering the drastic swelling effect and controllable swelling ratio, water swelling is used to replace the conventional pre-stretching and organic solvent swelling to fabricate stretchable conductors. In situ…

Detecting hydrogen peroxide (H2O2) as the side product of enzymatic reactions is of great interest in food and medical applications. Despite the advances in this field, the majority of reported H2O2 sensors are bulky, expensive, limited to only one phase detection (either gas or liquid), and require multistep fabrications. This article aims to address some of these limitations by presenting a 3D printable paper-based sensor made from poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) decorated with horseradish peroxidase, an enzyme able to interact with H2O2. Unlike most electrochemical PEDOT:PSS-based H2O2 sensors with voltametric or potentiometric mechanisms, the sensing mechanism in this technology is impedimetric, significantly…

The use of nanoparticles within living systems is a growing field, but the long‐term effects of introducing nanoparticles to a biological system are unknown. If nanoparticles remain localized after in vivo implantation unanticipated side effects due to unknown biodistribution can be avoided. Unfortunately, stabilization and retention of nanoparticles frequently alters their function.1 In this work multiple hydrogel platforms are developed to look at long‐term localization of nanoparticle sensors with the goal of developing a sensor platform that will stabilize and localize the nanoparticles without altering their function. Two different hydrogel platforms are presented, one with a liquid core of sensors…