Publications by authors named "Hanjun Ryu"

Hydrocephalus, a neurological disorder caused by an abnormal accumulation of cerebrospinal fluid (CSF) in the brain, manifests in symptoms such as headaches, blurred vision, and balance issues. While ventriculoperitoneal shunting is a common treatment, it has high failure rates, especially in pediatric patients. Recent progress in continuous, non-invasive monitoring using skin-mounted sensors based on anemometric techniques and transient plane source methods offer significant promise.

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Chronic wounds pose a significant healthcare challenge due to their risk of severe complications, necessitating effective management strategies. Bioresorbable materials have emerged as an innovative solution, offering advantages such as eliminating the need for secondary surgical removal, reducing infection risks, and enabling time-delayed drug delivery. This review examines recent advancements in bioresorbable wound healing materials, focusing on a systematic review of bioresorbable materials, systems incorporating electrical stimulation, and drug delivery technologies to accelerate tissue repair.

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Introduction: Stool characteristics may change depending on the endoscopic activity of ulcerative colitis (UC). We developed a deep learning model using stool photographs of patients with UC (DLSUC) to predict endoscopic mucosal inflammation.

Methods: This was a prospective multicenter study conducted in 6 tertiary referral hospitals.

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Partial cystectomy procedures for urinary bladder-related dysfunction involve long recovery periods, during which urodynamic studies (UDS) intermittently assess lower urinary tract function. However, UDS are not patient-friendly, they exhibit user-to-user variability, and they amount to snapshots in time, limiting the ability to collect continuous, longitudinal data. These procedures also pose the risk of catheter-associated urinary tract infections, which can progress to ascending pyelonephritis due to prolonged lower tract manipulation in high-risk patients.

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Wound healing is a highly orchestrated biological process characterized by sequential phases involving inflammation, proliferation, and tissue remodeling, and the role of endogenous electrical signals in regulating these phases has been highlighted. Recently, external electrostimulation has been shown to enhance these processes by promoting cell migration, extracellular matrix formation, and growth factor release while suppressing pro-inflammatory signals and reducing the risk of infection. Among the innovative approaches, piezoelectric and triboelectric nanogenerators have emerged as the next generation of flexible and wireless electronics designed for energy harvesting and efficiently converting mechanical energy into electrical power.

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Chronic wounds represent a major health risk for diabetic patients. Regeneration of such wounds requires regular medical treatments over periods that can extend for several months or more. Schemes for monitoring the healing process can provide important feedback to the patient and caregiver.

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Bioresorbable bioelectronics, with their natural degradation properties, hold significant potential to eliminate the need for surgical removal. Despite notable achievements, two major challenges hinder their practical application in medical settings. First, they necessitate sustainable energy solutions with biodegradable components via biosafe powering mechanisms.

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Myocardial infarction (MI) is one of the leading causes of death and disability. Recently developed cardiac patches provide mechanical support and additional conductive paths to promote electrical signal propagation in the MI area to synchronize cardiac excitation and contraction. Cardiac patches based on conductive polymers offer attractive features; however, the modest levels of elasticity and high impedance interfaces limit their mechanical and electrical performance.

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Diabetic foot ulcers are chronic wounds that affect millions and increase the risk of amputation and mortality, highlighting the critical need for their early detection. Recent demonstrations of wearable sensors enable real-time wound assessment, but they rely on bulky electronics, making them difficult to interface with wounds. Herein, a miniaturized, wireless, battery-free wound monitor that measures lactate in real-time and seamlessly integrates with bandages for conformal attachment to the wound bed is introduced.

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Article Synopsis
  • * Inflammation from these wounds disrupts natural electrical signals, which are crucial for the movement of skin cells necessary for healing; thus, electrical stimulation therapy is proposed as a potential treatment.
  • * A new wireless, battery-free, and bioresorbable electrotherapy device has been developed, successfully speeding up healing in diabetic mice by enhancing skin cell movement, reducing inflammation, and improving blood vessel formation while enabling monitoring of the healing process through impedance changes.
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Recently reported winged microelectronic systems offer passive flight mechanisms as a dispersal strategy for purposes in environmental monitoring, population surveillance, pathogen tracking, and other applications. Initial studies indicate potential for technologies of this type, but advances in structural and responsive materials and in aerodynamically optimized geometries are necessary to improve the functionality and expand the modes of operation. Here, we introduce environmentally degradable materials as the basis of 3D fliers that allow remote, colorimetric assessments of multiple environmental parameters-pH, heavy metal concentrations, and ultraviolet exposure, along with humidity levels and temperature.

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Local electrical stimulation of peripheral nerves can block the propagation of action potentials, as an attractive alternative to pharmacological agents for the treatment of acute pain. Traditional hardware for such purposes, however, involves interfaces that can damage nerve tissue and, when used for temporary pain relief, that impose costs and risks due to requirements for surgical extraction after a period of need. Here, we introduce a bioresorbable nerve stimulator that enables electrical nerve block and associated pain mitigation without these drawbacks.

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Nutrients play critical roles in maintaining core physiological functions and in preventing diseases. Technologies for delivering these nutrients and for monitoring their concentrations can help to ensure proper nutritional balance. Eccrine sweat is a potentially attractive class of biofluid for monitoring purposes due to the ability to capture sweat easily and noninvasively from nearly any region of the body using skin-integrated microfluidic technologies.

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Continuous monitoring of vital signs is an essential aspect of operations in neonatal and pediatric intensive care units (NICUs and PICUs), of particular importance to extremely premature and/or critically ill patients. Current approaches require multiple sensors taped to the skin and connected via hard-wired interfaces to external data acquisition electronics. The adhesives can cause iatrogenic injuries to fragile, underdeveloped skin, and the wires can complicate even the most routine tasks in patient care.

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Capabilities for continuous monitoring of pressures and temperatures at critical skin interfaces can help to guide care strategies that minimize the potential for pressure injuries in hospitalized patients or in individuals confined to the bed. This paper introduces a soft, skin-mountable class of sensor system for this purpose. The design includes a pressure-responsive element based on membrane deflection and a battery-free, wireless mode of operation capable of multi-site measurements at strategic locations across the body.

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Self-powered implantable devices have the potential to extend device operation time inside the body and reduce the necessity for high-risk repeated surgery. Without the technological innovation of in vivo energy harvesters driven by biomechanical energy, energy harvesters are insufficient and inconvenient to power titanium-packaged implantable medical devices. Here, we report on a commercial coin battery-sized high-performance inertia-driven triboelectric nanogenerator (I-TENG) based on body motion and gravity.

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Recently developed methods for transforming 2D patterns of thin-film materials into 3D mesostructures create many interesting opportunities in microsystems design. A growing area of interest is in multifunctional thermal, electrical, chemical, and optical interfaces to biological tissues, particularly 3D multicellular, millimeter-scale constructs, such as spheroids, assembloids, and organoids. Herein, examples of 3D mechanical interfaces are presented, in which thin ribbons of parylene-C form the basis of transparent, highly compliant frameworks that can be reversibly opened and closed to capture, envelop, and mechanically restrain fragile 3D tissues in a gentle, nondestructive manner, for precise measurements of viscoelastic properties using techniques in nanoindentation.

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Soft, skin-integrated electronic sensors can provide continuous measurements of diverse physiological parameters, with broad relevance to the future of human health care. Motion artifacts can, however, corrupt the recorded signals, particularly those associated with mechanical signatures of cardiopulmonary processes. Design strategies introduced here address this limitation through differential operation of a matched, time-synchronized pair of high-bandwidth accelerometers located on parts of the anatomy that exhibit strong spatial gradients in motion characteristics.

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Acute liver failure due to malignant melanoma is uncommon. We presents a case of acute liver failure secondary to hepatic infiltration of a malignant melanoma. An 86-year-old man was admitted with elevated liver enzymes and an increased lactate dehydrogenase level.

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Three-dimensional (3D), submillimeter-scale constructs of neural cells, known as cortical spheroids, are of rapidly growing importance in biological research because these systems reproduce complex features of the brain in vitro. Despite their great potential for studies of neurodevelopment and neurological disease modeling, 3D living objects cannot be studied easily using conventional approaches to neuromodulation, sensing, and manipulation. Here, we introduce classes of microfabricated 3D frameworks as compliant, multifunctional neural interfaces to spheroids and to assembloids.

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Limited opportunities exist for university premedical students to gain exposure to the realities of clinical practice through physician shadowing or through a formal curriculum. Medical Professionalism and Observership utilizes didactics, reflective writing, small- and large- group discussions, and clinical observerships to enhance the process of professional identity formation during a critical developmental window of late- adolescence. The pilot semester included a sample of 135 students, all in their sophomore, junior, or senior years of study at Rice University.

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Bioresorbable metals and metal alloys are of growing interest for myriad uses in temporary biomedical implants. Examples range from structural elements as stents, screws, and scaffolds to electronic components as sensors, electrical stimulators, and programmable fluidics. The associated physical forms span mechanically machined bulk parts to lithographically patterned conductive traces, across a diversity of metals and alloys based on magnesium, zinc, iron, tungsten, and others.

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. Real-time monitoring of the temperatures of regional tissue microenvironments can serve as the diagnostic basis for treating various health conditions and diseases. .

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Therapeutic compression garments (TCGs) are key tools for the management of a wide range of vascular lower extremity conditions. Proper use of TCGs involves application of a minimum and consistent pressure across the lower extremities for extended periods of time. Slight changes in the characteristics of the fabric and the mechanical properties of the tissues lead to requirements for frequent measurements and corresponding adjustments of the applied pressure.

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