In this paper, we report three-dimensional (3-D) liquid metal manipulation using electromagnets, which can be applied to electrical switching applications.

A gallium-based liquid metal got high attention recently, due to the excellent material properties that are useful in various research areas. We report here on electric field-induced liquid metal droplet generation and falling direction manipulation. The well-analyzed electro-hydrodynamic method is a selectable way to control the liquid metal, as the liquid metal is conductive. The electric field-induced liquid metal manipulation can be affected by the flow rate (0.05~0.2 mL/min), voltage (0~7 kV), and distance (15 and 30 mm) between electrodes, which changes the volume of the electric field-induced generated liquid metal droplet and the number of the generated droplets. When the electric field intensity increases or the flow rate increases, the generated droplet volume decreases, and the number of droplets increases. With the highest voltage of 7 kV with 15 mm between electrodes at the 0.2 mL/min flow rate, the lowest volume and the largest number of the generated droplets for 10 s were ~10 nL and 541, respectively. Additionally, we controlled the direction of the generated droplet by changing the electric field. The direction of the liquid metal droplet was controlled with the maximum angle of ~12°. Moreover, we exhibited a short circuit demonstration by controlling the volume or falling direction of the generated liquid metal droplet with an applied electric field.

We report magnetic field-driven dynamic morphological change of a liquid metal droplet: deformation and recovery; separation and merge. Low melting, non-toxic gallium-based liquid metal has been widely investigated due to its material properties and thus utilized to various applications. Morphological change of the liquid metal in required to tune characteristics of application. In order to enable the liquid metal to be non-wettable and magnetically controllable, we coated the surface with ferromagnetic iron (Fe) particles using hydrochloric acid (HCl) solution resulting in a magnetic liquid metal marble. With and without magnetic field, Fe particles-coated magnetic liquid metal marble was deformed and recovered readily. Against ~8 μL magnetic liquid metal marble, depending on the coated Fe particles mass, the shape deformation under magnetic field was changed: conventional (Fe < 4mg) and arbitrary (Fe ≥q 4mg) wetting shape. Accordingly, the deformability and recovery time of the magnetic liquid metal marble were varied. With an applied magnetic field, one marble was readily separated into 2, 3, and 4 marbles. Due to re-oxidation of the magnetic liquid metal marble surface, we treated the marble with HCl solution and vapor. Split and merge occurred depending on treatment time of HCl solution or vapor. Finally, we demonstrated magnetic field-based dynamic behavior which is reversible. [2020-0218]

Levated urinary levels of interleukin-1 α (IL-1α) and vascular endothelial growth factor (VEGF) have been reported in patients with interstitial cystitis (IC) relative to other inflammatory bladder diseases, highlighting their potential as biomarkers for disease diagnosis and therapeutic monitoring. No compact platform for the concurrent detection of these two IC-associated biomarkers in a urine matrix has been reported to date. Here, we present a single-chip multiplexed electrochemical biosensor for the simultaneous quantification of IL-1α and VEGF in artificial urine. The device was fabricated on a glass substrate using a combination of e-beam evaporation and screen-printing techniques. It exhibited dynamic detection ranges of 1–1,000 pg/mL for VEGF and 0.01–100 pg/mL for IL-1α, with limits of detection of 10 fg/mL and 1 fg/mL and response times of 20 s and 15 s, respectively. The biosensor demonstrated reproducibility with a relative standard deviation (RSD) below 3%, selectivity against common urinary interferents, including 0.5 mM glucose and 80 nM nitrite, and no measurable cross-reactivity between sensing channels. Repeatability testing across four consecutive calibration runs yielded an RSD below 0.1%. The platform further exhibited reversible responses over four ascending–descending concentration cycles, minimal signal drift during 12 h of continuous operation (overall RSD ≈ 0.6%), and stable performance over seven days (overall RSD = 1%). The capability to quantitatively monitor IL-1α and VEGF in real time using a single analytical platform supports its potential application in IC diagnosis, disease progression monitoring, and evaluation of therapeutic response at the point of care.

Bladder pain syndrome/interstitial cystitis (BPS/IC) is a chronic urological condition characterized by pelvic pain and urinary urgency, often misdiagnosed due to symptom overlap with other analogous disorders. The absence of specific, noninvasive biomarkers complicates its diagnosis and hinders effective monitoring of disease progression and therapeutic response. C-C motif chemokine ligand 5 (CCL5) is recognized as a potential inflammatory biomarker for BPS/IC, while urinary potassium (K⁺) levels reflect epithelial barrier dysfunction. In this letter, we present a novel screen-printed, low-cost, and rapid electrochemical sensor for simultaneous point-of-care detection of CCL5 and K⁺ in urine samples. The sensor employs immunosensing and ion-selective membrane strategies to achieve excellent sensitivity, selectivity, and operational stability, having a low detection limit of 60 fg/mL and 80 pM for CCL5 and K⁺ ion sensing electrodes. The dual-detection approach offers valuable insights into both inflammatory status and urothelial integrity, holds promise for early diagnosis and therapeutic strategy with improved patient stratification, and real-time personalized monitoring in BPS/IC.