<p>To elucidate the mechanisms of cellular mechanotransduction, it is necessary to employ biomaterials that effectively merge biofunctionality with appropriate mechanical characteristics. Agarose is a standard biopolymer used in cartilage mechanobiology but lacks necessary adhesion motifs for cell-matrix interactions to complete mechanostransduction studies. Collagen type I is a natural biomaterial used in cartilage mechanotransduction studies but creates an environment much softer than native cartilage tissue.  In these studies, agarose was blended at two final concentrations (2% w/v and 4% w/v) with collagen type I (2 mg/mL). The overarching goal was to determine whether a composite hydrogel of agarose and collagen can create a mechanically and biologically suitable matrix for chondrocyte studies. First, hydrogels were characterized by rheologic and compressive properties, contraction, and structural homogeneity. Following baseline characterization, primary murine chondrocytes were embedded (1 × 106 cells/mL) within the hydrogels to assess the longer-term <em>in vitro</em> impact on matrix mechanics, cell proliferation, sulfated glycosaminoglycan (sGAG) content, and cellular morphology. To begin probing questions about physiologic loading conditions that chondrocytes experience <em>in</em> <em>vivo</em>, a custom compression loading system was validated using cell-laden hydrogels. Briefly, the 4% agarose – 2 mg/mL collagen I hydrogel composites were able to retain chondrocyte morphology over 21 days in culture, resulted in continual sGAG production, and had bulk mechanics similar to that of the stiffest hydrogel material tested, indicating this hydrogel class may be promising towards developing an effective hydrogel for chondrocyte mechanotransduction and mechanobiology studies, a critical step towards a fuller understanding of cell-matrix interactions. </p>

<p>Swift recognition of disease-causing pathogens at the point-of-care enables life-saving treatment and infection control. However, current rapid diagnostic devices often fail to detect the low concentrations of pathogens present in the early stages of infection, causing delayed and even incorrect treatments. Rapid diagnostics that require multiple steps and/or elevated temperatures to perform have a number of barriers to use at the point-of-care and in the field, and despite efforts to simplify these platforms for ease of use, many still require diagnostic-specific training for the healthcare professionals who use them. Most nucleic acid amplification assays require hours to perform in a sterile laboratory setting that may be still more hours from a patient’s bedside or not at all feasible for transport in remote or low-resourced areas. The cold-chain storage of reagents, multistep sample preparation, and costly instrumentation required to analyze samples has prohibited many nucleic acid detection and antibody-based assays from reaching the point-of-care. There remains a critical need to bring rapid and accessible pathogen identification technologies that determine disease status and ensure effective treatment out of the laboratory.</p> <p>Paper-based diagnostics have emerged as a portable platform for antigen and nucleic acid detection of pathogens but are often limited by their imperfect control of reagent incubation, multiple complex steps, and inconsistent false positive results. Here, I have developed mechanisms to economically improve thermal incubations, automate dried reagent flow for multistep assays, and specifically detect pathogenic antigens while improving final output sensitivity on paper-based devices. First, I characterize miniaturized inkjet printed joule-heaters (microheaters) that enable thermal control for pathogen lysis and nucleic acid amplification incubation on a low-cost paper-based device. Next, I explore 2-Dimensional Paper Networks as a means to automate multistep visual enhancement reactions with dried reagents to increase the sensitivity and readability of nucleic acid detection with paper-based devices. Lastly, I aim to create a novel Reverse-Transcription Recombinase Polymerase Reaction mechanism to amplify and detect a specific region of the Spike protein domain of SARS-CoV-2. This will allow the rapid detection of SARS-CoV-2 infections to aid in managing the current COVID-19 pandemic. In the future, these tools could be integrated into a rapid diagnostic test for SARS-CoV-2 and other pathogens, ultimately improving the accessibility and sensitivity of rapid diagnostics on multiple fronts.</p>

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No description available.

Transfemoral amputees around the world experience increased difficulty in climbing stairs due to lack of muscle, balance, and other factors. The loss of a lower limb greatly diminishes the amount of natural force generation provided that is necessary to propel oneself up stairs. This study investigated possible solutions to the problem of stair ascension for transfemoral amputees by the means of designing and developing an externally attachable device to a prosthesis. The number of amputations from military service has greatly increased since 2008, which shows there is a clear need for assistive devices (Wenke, Krueger, & Ficke, 2012). With the number of amputations rising and no current externally attachable products on the market to aid in stair ascension for transfemoral amputees, the need for this specific device has become more prominent. Research, previous work, and preliminary testing provided a basis for design and development of a new prototype. Bench top testing was conducted to review concepts in the prototype and provide data for further modifications. Results from testing of previous work, as well as testing of new concepts and modifications, provided a framework for designing a new externally attachable device for assistance in stair ascension. A new prototype was then designed, manufactured, and tested with bench models as well as real-time testing with amputees. Success of the device’s performance was based on bench top results and feedback from amputees, noting both the advantages and shortcomings of the new prototype. Testing provided results and feedback that the device was well built and functioned properly, but did not perform satisfactorily, particularly in the categories of force generation and balance.

Yes / Introduction: Clinicians typically use findings from cohort studies to objectively inform judgements regarding the potential (dis)advantages of prescribing a new prosthetic device. However, before finalising prescription a clinician will typically ask a patient to ‘try out’ a change of prosthetic device while the patient is at the clinic. Observed differences in gait when using the new device should be the result of the device’s mechanical function, but could also conceivably be due to patient related factors which can change from day-to-day and can thus make device comparisons unreliable. To determine whether a device’s mechanical function consistently has a more meaningful impact on gait than patient-related factors, the present study undertook quantitative gait analyses of a trans-tibial amputee walking using two different foot-ankle devices on two occasions over a year apart. If the observed differences present between devices, established using quantitative gait analysis, were in the same direction and of similar magnitude on each of the two occasions, this would indicate that device-related factors were more important than patient-related factors. Methods: One adult male with a unilateral trans-tibial amputation completed repeated walking trials using two different prosthetic foot devices on two separate occasions, 14 months apart. Walking speed and sagittal plane joint kinematics and kinetics for both limbs were assessed on each occasion. Clinically meaningful differences in these biomechanical outcome variables were defined as those with an effect size difference (d) between prosthetic conditions of at least 0.4 (i.e. ‘medium’ effect size). Results: Eight variables namely, walking speed, prosthetic ‘ankle’ peak plantar- and dorsi- flexion and peak positive power, and residual knee loading response flexion, peak stance-phase extension and flexion moments and peak negative power, displayed clinically meaningful differences (d > 0.4) between foot devices during the first session. All eight of these showed similar effect size differences during the second session despite the participant being heavier and older. Conclusions: Findings suggest that a prosthetic device’s mechanical function consistently has a more meaningful impact on gait than patient-related factors. These findings support the current clinical practice of making decisions regarding prosthetic prescription for an individual, based on a single session evaluation of their gait using two different devices. However, to confirm this conclusion, a case series using the same approach as the present study could be undertaken.

Yes / Passive prosthetic devices are set up to provide optimal function at customary walking speed and thus may function less effectively at other speeds. This partly explains why joint kinetic adaptations become more apparent in lower-limb amputees when walking at speeds other than customary. The present study determined whether a trans-tibial prosthesis incorporating a dynamic-response foot that was attached to the shank via an articulating hydraulic device (hyA-F) lessened speed-related adaptations in joint kinetics compared to when the foot was attached via a rigid, non-articulating attachment (rigF). Eight active unilateral trans-tibial amputees completed walking trials at their customary walking speed, and at speeds they deemed to be slow-comfortable and fast-comfortable whilst using each type of foot attachment. Moments and powers at the distal end of the prosthetic shank and at the intact joints of both limbs were compared between attachment conditions. There was no change in the amount of intact-limb ankle work across speed or attachment conditions. As speed level increased there was an increase on both limbs in the amount of hip and knee joint work done, and increases on the prosthetic side were greater when using the hyA-F. However, because all walking speed levels were higher when using the hyA-F, the intact-limb ankle and combined joints work per meter travelled were significantly lower; particularly so at the customary speed level. This was the case despite the hyA-F dissipating more energy during stance. In addition, the amount of eccentric work done per meter travelled became increased at the residual knee when using the hyA-F, with increases again greatest at customary speed. Findings indicate that a trans-tibial prosthesis incorporating a dynamic-response foot reduced speed-related changes in compensatory intact-limb joint kinetics when the foot was attached via an articulating hydraulic device compared to rigid attachment. As differences between attachment conditions were greatest at customary speed, findings indicate a hydraulic ankle-foot device is most effectual at the speed it is set-up for.

<p>  </p> <p>In this study, we present advancements in smart contact lenses, highlighting their potential as minimally or non-invasive diagnostic and drug delivery platforms. The eyes, rich in physiological and diagnostic data, make contact lens sensors an effective tool for disease diagnosis. These sensors, particularly smart contact lenses, can measure various biomolecules like glucose, urea, ascorbate, and electrolytes (Na+, K+, Cl-, HCO3-) in ocular fluids, along with physical biomarkers such as movement of the eye, intraocular pressure (IOP) and ocular surface temperature (OST).</p> <p>The study explores the use of continuous, non-invasive contact lens sensors in clinical or point-of-care settings. Although promising, their practical application is hindered by the developmental stage of the field. This thesis addresses these challenges by examining the integration of contact lens sensors, covering their working principle, fabrication, sensitivity, and readout mechanisms, with a focus on monitoring glaucoma and eye health conditions like dry eye syndrome and inflammation.</p> <p>Our design adapts these sensors to fit various corneal curvatures and thicknesses. The lenses can visually indicate IOP through microfluidic channels' mechanical deformation under ambulatory conditions. We also introduce a colorimetric hydrogel tear fluid sensor that detects pH, electrolytes, and ocular surface temperature, indicating conditions like dry eye disease and inflammation.</p> <p>The evaluation of these contact lens sensors includes in vivo/vitro biocompatibility, ex vivo functionality studies, and in vivo safety assessments. Our comprehensive analysis aims to enhance the practicality and effectiveness of smart contact lenses in ophthalmic diagnostics and therapeutics.</p>

No description available.

No description available.