An official website of the United States government
Abstract Three-dimensional (3D) bio-printing is a rapidly growing field attempting to recreate functional tissues for medical and pharmaceutical purposes. The printability of multiple materials encapsulating various living cells can take this emerging effort closer to tissue regeneration. In our earlier research, we designed a Y-like nozzle connector system capable of switching materials between more than one filament with continuous deposition. The device had a fixed switching angle, was made from plastic, and was suitable for one-time use. This paper presents the extension of our previously proposed nozzle system. We considered 30°, 45°, 60°, and 90° angles (vertical and tilted) between the two materials and chose stainless steel as a material to fabricate those nozzle connectors. The overall material switching time was recorded and compared to analyze the effects of those various angles. Our previously developed hybrid hydrogel (4% Alginate and 4% Carboxymethyl Cellulose, CMC) was used as a test material to flow through the nozzle system. These in-house fabricated nozzle connectors are reusable, easy to clean, and sterile, allowing smooth material transition and flow.
more »
« less
Precision Delivery of Multiscale Payloads to Tissue‐Specific Targets in Plants
Abstract 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 demonstratedAgrobacterium‐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 deliveryin plantaopens new avenues to enhance plant resistance to biotic and abiotic stresses, provides new tools for diagnostics, and enables new opportunities in plant engineering.
more »
« less
- Award ID(s):
- 1752172
- PAR ID:
- 10457490
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Science
- Volume:
- 7
- Issue:
- 13
- ISSN:
- 2198-3844
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Controlling the deformation of a soft body has potential applications in fields requiring precise control over the shape of the body. Areas such as medical robotics can use the shape control of soft robots to repair aneurysms in humans, deliver medicines within the body, among other applications. However, given known external loading, it is usually not possible to deform a soft body into arbitrary shapes if it is fabricated using only a single material. In this work, we propose a new physics-based method for the computational design of soft hyperelastic bodies to address this problem. The method takes as input an undeformed shape of a body, a specified external load, and a user desired final shape. It then solves an inverse problem in design using nonlinear optimization subject to physics constraints. The nonlinear program is solved using a gradient-based interior-point method. Analytical gradients are computed for efficiency. The method outputs fields of material properties which can be used to fabricate a soft body. A body fabricated to match this material field is expected to deform into a user-desired shape, given the same external loading input. Two regularizers are used to ascribea prioricharacteristics of smoothness and contrast, respectively, to the spatial distribution of material fields. The performance of the method is tested on three example cases in silico.more » « less
-
Abstract PremiseDetecting clear tissue‐ and organ‐specific patterns of gene expression is key to understanding the genetic mechanisms that control plant development. In situ hybridization (ISH) of mRNA is one of the most precise, yet most challenging approaches to gene expression assays. Methods and ResultsDetection of histone H4 expression in reproductive tissues ofMimulus lewisii, a model angiosperm, was optimized using the RNAscope ISH assay. The optimized protocol was used to detect histone H4 expression in reproductive tissues of two gymnosperm species,Taxodium distichumandJuniperus virginiana, without further need for species‐specific optimization. Additionally, the optimized protocol was used to detect expression ofCYCLOIDEAtranscription factors inM. lewisiireproductive tissues without further optimization and with results similar to those previously reported. ConclusionsThe RNAscope assay can quickly and sensitively generate high‐quality ISH results in reproductive tissues across a breadth of plant species.more » « less
-
ABSTRACT A fascinating feature of land plants is their ability to continually initiate new tissues and organs throughout their lifespan, driven by a pool of pluripotent stem cells located in meristems. In seed plants, various types of meristems are initiated and maintained during the sporophyte generation, while their gametophytes lack meristems and rely on sporophyte tissues for growth. In contrast, seed‐free vascular plants, such as ferns, develop meristems during both the sporophyte and gametophyte generations, allowing for the independent growth of both generations. Recent findings have highlighted both conserved and lineage‐specific roles of the HAIRY MERISTEM (HAM) family of GRAS‐domain transcriptional regulators in various meristems throughout the land plant lifecycle. Here, we review and discuss howHAMgenes maintain meristem indeterminacy in both sporophytes and gametophytes, with a focus on studies performed in two model species: the flowering plantArabidopsis thalianaand the fernCeratopteris richardii. Additionally, we summarize the crucial and tightly regulated functions of the microRNA171 (miR171)‐HAM regulatory modules, which define HAM spatial patterns and activities during meristem development across various meristem identities in land plants.more » « less
-
Tissue engineering is an interdisciplinary field combining biology, chemistry, and engineering to create implantable structures that support healing and regeneration. Autografts, tissues taken from a patient’s own body, are commonly used due to their high compatibility and minimal disease transmission risk. However, autografts are limited by the small amount of tissue that can be harvested. Allografts, or transplants from one person to another, provide a more natural alternative to synthetic or metal implants, yet their use is constrained by limited donor availability, high rejection rates, and significant operating costs. Although synthetic polymer, ceramic, and metallic implants have gained popularity due to their affordability and durability, they often lead to chronic pain, restricted movement, and eventual reimplantation because of issues like surface wear and reduced lubrication. Advances in artificial intelligence (AI), machine learning (ML), and 3D printing are opening new possibilities in tissue engineering. Researchers are now exploring natural polymers as an alternative to synthetic materials by focusing on the structural complexities and sustainability of native tissues. For example, type I collagen (Col), the most abundant protein in human connective tissues, shows promise as a replacement for titanium in bone tissue engineering due to its excellent mechanical properties, biocompatibility, and ability to support bone growth (osteogenesis). When combined with hydroxyapatite (HAp), Col-HAp composites can closely mimic the natural organic-inorganic structure of bone, providing both the chemical and physical properties needed to promote tissue healing and regeneration. However, the extraction and processing of collagen pose challenges, as they can degrade its natural properties and complicate the 3D printing of implants. This perspective examines the processing, characterization, and manufacturability of Col, its composites, and other robust biomaterials for bone tissue engineering, aiming to replicate the mechanical behavior of human limbs under both static and dynamic conditions. It also explores how AI and ML can enhance the precision and reproducibility of Col composite printing and enable generative scaffold design to foster vascularization, cell viability, and tissue growth. Finally, this work underscores the advancements in novel and customized 3D bioprinting systems designed to address patient-specific requirements, promote higher cell proliferation, and fabricate complex scaffold structures with improved structural properties.more » « less
