Blood Banking in Living Droplets

Blood banking has a broad public health impact influencing millions of lives daily. It could potentially benefit from emerging biopreservation technologies. However, although vitrification has shown advantages over traditional cryopreservation techniques, it has not been incorporated into transfusion medicine mainly due to throughput challenges. Here, we present a scalable method that can vitrify red blood cells in microdroplets. This approach enables the vitrification of large volumes of blood in a short amount of time, and makes it a viable and scalable biotechnology tool for blood cryopreservation.National Institutes of Health (U.S.) (NIH R21 EB007707)Wallace H. Coulter FoundationUnited States. Army Medical Research and Materiel Command (Acquisition Activity Cooperative Agreement RO1 A1081534)Center for Integration of Medicine and Innovative TechnologyUnited States. Army Medical Research and Materiel Command (Acquisition Activity Cooperative Agreement R21 AI087107)United States. Army. Telemedicine & Advanced Technology Research Cente

Design and optimization of x-y-[t̳h̳e̳t̳a̳]z̳, cylindrical flexure stage

Thesis (S.B.)--Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis. In title on title page, double-underscored "t̳h̳e̳t̳a̳" appears as Greek letter. In title on title page, double underscored "z̳" appears as subscript.Includes bibliographical references (pages 63-64).Cylindrical flexures (CFs) are composed of curved beams whose length is defined by a radius, R, and a sweep angle, [phi], [1]. The curved nature of the beams results in additional kinematics, requiring additional design rules beyond those used for straight-beam flexures. The curvature also adds additional parameters that allow for adjustments, suggesting that CFs may meet requirements that cannot be met with straight-beams. CFs have the potential to further open the flexure design space. In this study, cylindrical flexure design rules and models were used to optimize an x-y-[theta]z stage design for a Dip-pen nanolithography (DPN) application. DPN a nanometer-scale fabrication technology that uses an atomic force microscope (AFM) cantilevered tip to place chemical compounds on a substrate. The flexure designed aids in alignment of the tip relative to the machine, increasing accuracy and repeatability. The first step to design a flexure system is applying CF design rules to create a system that best fits functional requirements. Several different system configurations were considered, since reaching an optimal design is a highly iterative process. Once the best configuration was determined, element parameters were optimized using CF design rules. The optimized design was then corroborated using finite element analysis (FEA). The CF design rules greatly informed the design, reducing time spent on FEA by quickly narrowing in on successful designs. The finalized flexure design was fabricated using a waterjet machine and placed in a testing apparatus designed to measure predicted stiffnesses and verify functionality. The CF model predicted the final measurements quite closely, although there were variability in the measurements and simplifications in the model. In K[theta]z, the error was as small as 0.3%, while the other stiffnesses had errors around 30%, except for Kx, which is twice as stiff than the model. This could be due to the simplification of more complicated tip boundary condition effects in the model or error in measurement of the fabricated flexure. Although the model did not predict the final stiffness values exactly, it was critical in reducing time spent optimizing the system by quickly determining key parameters. The process of design and optimization shed light on advantages and disadvantages of using cylindrical flexures for an x-y-[theta]z stage in general, and demonstrated the usability of CF rules. Observations from this research augmented the design guidelines, which will help others design CFs for other functional requirements.by Laura Yu Matloff.S.B

Video of four and six bar wing mechanisms from How pigeons couple three-dimensional elbow and wrist motion to morph their wings

Including wrist bones in a six-bar mechanism improves the model's performance in tracking measured wing bone motion. This video compares the four-bar wing model with fused wrist bones and a full six-bar wing model with the measured bone locations (both mechanisms are shown as cartoons in Figure 6). The measured locations of the large bones are shown in grey, while the modeled bones are shown in color

Video of non-planar wing morphing from How pigeons couple three-dimensional elbow and wrist motion to morph their wings

Wing skeletal motion is non-planar and deviates from the anatomical plane. In the ventral view, the wing bones appear to follow a traditional four-bar ‘drawing parallels’ pattern. However, when we rotate to the anterior view, we see the wing bones move out of plane, demonstrating that the overall motion is non-planar and therefore a 2D ‘drawing parallels’ model is insufficient. Skeletal motion is shown in the reference frames shown in figure 2

Supplemental text, tables and figures from How pigeons couple three-dimensional elbow and wrist motion to morph their wings

Birds change the shape and area of their wings to an exceptional degree, surpassing insects, bats and aircraft in their ability to morph their wings for a variety of tasks. This morphing is governed by a musculoskeletal system, which couples elbow and wrist motion. Since the discovery of this effect in 1839, the planar ‘drawing parallels’ mechanism has been used to explain the coupling. Remarkably, this mechanism has never been corroborated from quantitative motion data. Therefore, we measured how the wing skeleton of a pigeon (<i>Columba livia</i>) moves during morphing. Despite earlier planar assumptions, we found that the skeletal motion paths are highly three-dimensional and do not lie in the anatomical plane, ruling out the ‘drawing parallels’ mechanism. Furthermore, μCT scans in seven consecutive poses show how the two wrist bones contribute to morphing, particularly the sliding ulnare. From these data, we infer the joint types for all six bones that form the wing morphing mechanism and corroborate the most parsimonious mechanism based on least-squares error minimization. Remarkably, the algorithm shows that all optimal four-bar mechanisms either lock, unable to track the highly three-dimensional bone motion paths, or require the radius and ulna to cross for accuracy, which is anatomically unrealistic. In contrast, the algorithm finds that a six-bar mechanism recreates the measured motion accurately with a parallel radius and ulna and a sliding ulnare. This revises our mechanistic understanding of how birds morph their wings, and offers quantitative inspiration for engineering morphing wings

Criteria used in rating figure 10 from Inspiration for wing design: how forelimb specialization enables active flight in modern vertebrates

Criteria used to rate maneuverability, glide ratio, speed, adaptability and robustness in figure 10

Letter to Referees from Inspiration for wing design: how forelimb specialization enables active flight in modern vertebrates

Harnessing flight strategies refined by millions of years of evolution can help expedite the design of more efficient, manoeuvrable and robust flying robots. This review synthesizes recent advances and highlights remaining gaps in our understanding of how bird and bat wing adaptations enable effective flight. Included in this discussion is an evaluation of how current robotic analogues measure to their biological sources of inspiration. Studies of vertebrate wings have revealed skeletal systems well suited for enduring the loads required during flight, but the mechanisms that drive coordinated motions between bones and connected integuments remain ill-described. Similarly, vertebrate flight muscles have adapted to sustain increased wing loading, but a lack of <i>in vivo</i> studies limits our understanding of specific muscular functions. Forelimb adaptations diverge at the integument level, but both bird feathers and bat membranes yield aerodynamic surfaces with a level of robustness unparalleled by engineered wings. These morphological adaptations enable a diverse range of kinematics tuned for different flight speeds and manoeuvres. By integrating vertebrate flight specializations—particularly those that enable greater robustness and adaptability—into the design and control of robotic wings, engineers can begin narrowing the wide margin that currently exists between flying robots and vertebrates. In turn, these robotic wings can help biologists create experiments that would be impossible <i>in vivo</i>