Jayoung Kim

Wearable salivary uric acid mouthguard biosensor with integrated wireless electronics

This article demonstrates an instrumented mouthguard capable of non-invasively monitoring salivary uric acid (SUA) levels. The enzyme (uricase)-modified screen printed electrode system has been integrated onto a mouthguard platform along with anatomically-miniaturized instrumentation electronics featuring a potentiostat, microcontroller, and a Bluetooth Low Energy (BLE) transceiver. Unlike RFID-based biosensing systems, which require large proximal power sources, the developed platform enables real-time wireless transmission of the sensed information to standard smartphones, laptops, and other consumer electronics for on-demand processing, diagnostics, or storage. The mouthguard biosensor system offers high sensitivity, selectivity, and stability towards uric acid detection in human saliva, covering the concentration ranges for both healthy people and hyperuricemia patients. The new wireless mouthguard biosensor system is able to monitor SUA level in real-time and continuous fashion, and can be readily expanded to an array of sensors for different analytes to enable an attractive wearable monitoring system for diverse health and fitness applications.

Epidermal Microfluidic Electrochemical Detection System: Enhanced Sweat Sampling and Metabolite Detection

Despite tremendous recent efforts, noninvasive sweat monitoring is still far from delivering its early analytical promise. Here, we describe a flexible epidermal microfluidic detection platform fabricated through hybridization of lithographic and screen-printed technologies, for efficient and fast sweat sampling and continuous, real-time electrochemical monitoring of glucose and lactate levels. This soft, skin-mounted device judiciously merges lab-on-a-chip and electrochemical detection technologies, integrated with a miniaturized flexible electronic board for real-time wireless data transmission to a mobile device. Modeling of the device design and sweat flow conditions allowed optimization of the sampling process and the microchannel layout for achieving attractive fluid dynamics and rapid filling of the detection reservoir (within 8 min from starting exercise). The wearable microdevice thus enabled efficient natural sweat pumping to the electrochemical detection chamber containing the enzyme-modified electrode transducers. The fabricated device can be easily mounted on the epidermis without hindrance to the wearer and displays resiliency against continuous mechanical deformation expected from such epidermal wear. Amperometric biosensing of lactate and glucose from the rapidly generated sweat, using the corresponding immobilized oxidase enzymes, was wirelessly monitored during cycling activity of different healthy subjects. This ability to monitor sweat glucose levels introduces new possibilities for effective diabetes management, while similar lactate monitoring paves the way for new wearable fitness applications. The new epidermal microfluidic electrochemical detection strategy represents an attractive alternative to recently reported colorimetric sweat-monitoring methods, and hence holds considerable promise for practical fitness or health monitoring applications.

Wearable non-invasive epidermal glucose sensors: A review

The growing recent interest in wearable and mobile technologies has led to increased research efforts toward development of non-invasive glucose monitoring platforms. Continuous glucose monitoring addresses the limitations of finger-stick blood testing and provides the opportunity for optimal therapeutic interventions. This article reviews recent advances and challenges toward the development of non-invasive epidermal electrochemical glucose sensing systems. Recent reports claim success in glucose monitoring in human subjects using skin-worn electrochemical sensors. Such epidermal electrochemical biosensors obviate the disadvantages of minimally-invasive subcutaneous glucose biosensors and offer promise for improved glycemic control. The ability of such systems to monitor glucose non-invasively offers an attractive route toward advancing the management of diabetes and achieving improved glycemic control. However, realizing the potential diagnostic impact of these new epidermal sensing strategies would require extensive efforts toward addressing key technological challenges and establishing a reliable correlation to gold standard blood glucose meters.

Interstitial Cystitis-Associated Urinary Metabolites Identified by Mass-Spectrometry Based Metabolomics Analysis

This study on interstitial cystitis (IC) aims to identify a unique urine metabolomic profile associated with IC, which can be defined as an unpleasant sensation including pain and discomfort related to the urinary bladder, without infection or other identifiable causes. Although the burden of IC on the American public is immense in both human and financial terms, there is no clear diagnostic test for IC, but rather it is a disease of exclusion. Very little is known about the clinically useful urinary biomarkers of IC, which are desperately needed. Untargeted comprehensive metabolomic profiling was performed using gas-chromatography/mass-spectrometry to compare urine specimens of IC patients or health donors. The study profiled 200 known and 290 unknown metabolites. The majority of the thirty significantly changed metabolites before false discovery rate correction were unknown compounds. Partial least square discriminant analysis clearly separated IC patients from controls. The high number of unknown compounds hinders useful biological interpretation of such predictive models. Given that urine analyses have great potential to be adapted in clinical practice, research has to be focused on the identification of unknown compounds to uncover important clues about underlying disease mechanisms.

Urinary proteomics and metabolomics studies to monitor bladder health and urological diseases

BackgroundAssays of molecular biomarkers in urine are non-invasive compared to other body fluids and can be easily repeated. Based on the hypothesis that the secreted markers from the diseased organs may locally release into the body fluid in the vicinity of the injury, urine-based assays have been considered beneficial to monitoring bladder health and urological diseases. The urine proteome is much less complex than the serum and tissues, but nevertheless can contain biomarkers for diagnosis and prognosis of diseases. The urine metabolome has a much higher number and concentration of low-molecular metabolites than the serum or tissues, with a far lower lipid concentration, yet informs directly about dietary and microbial metabolism.DiscussionWe here discuss the use of mass spectrometry-based proteomics and metabolomics for urine biomarker assays, specifically with respect to the underlying mechanisms that trigger the pathological condition.ConclusionMolecular biomarker profiles, based on proteomics and metabolomics studies, reliably distinguish patients from healthy controls, stratify sub-populations with respect to treatment options, and predict therapeutic response of patients with urological disease.

Immune checkpoint blockade therapy for bladder cancer treatment.

Bladder cancer remains the most immunogenic and expensive malignant tumor in the United States today. As the 4th leading cause of death from cancer in United States, Immunotherapy blocking immune checkpoints have been recently been applied to many aggressive cancers and changed interventions of urological cancers including advanced bladder cancer. The applied inhibition of PD-1–PD-L1 interactions can restore antitumor T-cell activity and enhance the cellular immune attack on antigens. The overall goals of this short review article are to introduce current cancer immunotherapy and immune checkpoint inhibitors, and to provide new insight into the underlying mechanisms that block immune checkpoints in tumor microenvironment. Furthermore, this review will address the preclinical and clinical trials to determine whether bladder cancer patients could benefit from this new cancer therapy in near future.

A wearable fingernail chemical sensing platform: pH sensing at your fingertips

This article demonstrates an example of a wearable chemical sensor based on a fingernail platform. Fingernails represent an attractive wearable platform, merging beauty products with chemical sensing, to enable monitoring of our surrounding environment. The new colorimetric pH fingernail sensor relies on coating artificial nails with a recognition layer consisted of pH indicators entrapped in a polyvinyl chloride (PVC) matrix. Such color changing fingernails offer fast and reversible response to pH changes, repeated use, and intense color change detected easily with naked eye. The PVC matrix prevents leaching out of the indicator molecules from the fingernail sensor toward such repeated use. The limited narrow working pH range of a single pH indicator has been addressed by multiplexing three different pH indicators: bromothymol blue (pH 6.0-7.6), bromocresol green (pH 3.8-5.4), and cresol red (pH 7.2-8.8), as demonstrated for analyses of real-life samples of acidic, neutral, and basic character. The new concept of an optical wearable chemical sensor on fingernail platforms can be expanded towards diverse analytes for various applications in connection to the judicious design of the recognition layer.

Wearable chemical sensors: Opportunities and challenges

Wearable systems show considerable promise in monitoring and assessing the real-time performance of athletes, the health status of patients, or the general well-being of interested users. Most wearables today focus on monitoring physical parameters (e.g., activity, respiration rate, etc.), or electrophysiology (e.g., ECG, EEG, etc.). In order to augment the richness of collected data, the next-generation of wearables will also be capable of monitoring underlying chemical homeostatis of the user, for example through measurement of glucose in interstitial fluid, lactate in saliva, or electrolytes in sweat. This paper discusses the challenges of building wearable chemical biosensors, including biosensor functionalization, flexible material engineering, bioelectronic integration, and data analytics.

Unmasking molecular profiles of bladder cancer

Precision medicine is designed to tailor treatments for individual patients by factoring in each persons specific biology and mechanism of disease. This paradigm shifted from a “one size fits all” approach to “personalized and precision care” requires multiple layers of molecular profiling of biomarkers for accurate diagnosis and prediction of treatment responses. Intensive studies are also being performed to understand the complex and dynamic molecular profiles of bladder cancer. These efforts involve looking bladder cancer mechanism at the multiple levels of the genome, epigenome, transcriptome, proteome, lipidome, metabolome etc. The aim of this short review is to outline the current technologies being used to investigate molecular profiles and discuss biomarker candidates that have been investigated as possible diagnostic and prognostic indicators of bladder cancer.

Looking to the metabolic landscapes for prostate health monitoring

Abnormal metabolism is a widely accepted biological signature of prostatic diseases, including prostate cancer and benign prostate hyperplasia. Recently accumulated epidemiological and experimental evidence illustrate that the metabolic syndrome, impaired mitochondrial function, and prostatic pathological conditions intersect. The perturbed metabolism and metabolic mediates influence key signaling pathways in various prostatic pathological conditions. This short review article aids to highlight recent findings on metabolism, metabolic mechanisms, and mitochondrial metabolism as a possible route to finding a cure for prostate diseases, including prostate cancer. The effort to better understand the role that mitochondria plays in cancer metabolism and the biological meaning of defective and/or deleted mitochondrial DNA in cancer will also be discussed.