Triple-State Liquid-Based Microfluidic Tactile Sensor with High Flexibility, Durability, and Sensitivity

We develop a novel triple-state liquid-based resistive microfluidic tactile sensor with high flexibility, durability, and sensitivity. It comprises a platinum-cured silicone microfluidic assembly filled with 2 μL liquid metallic alloy interfacing two screen-printed conductive electrodes on a polyethylene terephthalate (PET) film. This flexible tactile sensor is highly sensitive ((2–20) × 10^–3 kPa^–1) and capable of distinguishing compressive loads with an extremely large range of pressure (2 to 400 kPa) as well as bending loads. Owing to its unique and durable structure, the sensor can withstand numerous severe mechanical load, such as foot stomping and a car wheel rolling over it, without compromising its electrical signal stability and overall integrity. Also, our sensing device is highly deformable, wearable, and able to differentiate and quantify pressures exerted by distinct bodily actions, such as a finger touch or footstep pressure. As a proof-of-concept of the applicability of our tactile sensor, we demonstrate the measurements of localized dynamic foot pressure by embedding the sensor inside the shoes and high heels. This work highlights the potential of the liquid-based microfluidic tactile sensing platform in a wide range of applications and can facilitate the realization of functional liquid-state sensing device technology with superior mechanical flexibility, durability, and sensitivity

Aggregation-Induced Emission Probe for Specific Turn-On Quantification of Soluble Transferrin Receptor: An Important Disease Marker for Iron Deficiency Anemia and Kidney Diseases

Transferrin receptor (TfR) is overexpressed on the surface of many cancer cells due to its vital roles in iron circulation and cellular respiration. Soluble transferrin receptor (sTfR), a truncated extracellular form of TfR in serum, is an important marker of iron deficiency anemia (IDA) and bone marrow failure in cancer patients. More recently, sTfR level in urine has been related to a specific kidney disease of Henoch–Schönlein purpura nephritis (HSPN). Despite the universal significance of sTfR, there is still a lack of a simple and sensitive method for the quantification of sTfR. Furthermore, it is desirable to have a probe that can detect both TfR and sTfR for further comparison study. In this work, we developed a water-soluble AIE–peptide conjugate with aggregation-induced emission (AIE) characteristics. Taking advantage of the negligible emission from molecularly dissolved tetraphenylethene (TPE), probe TPE-2T7 was used for the light-up detection of sTfR. The probe itself is nonemissive in aqueous solution, but it turns on its fluorescence upon interaction with sTfR to yield a detection limit of 0.27 μg/mL, which is much lower than the sTfR level in IDA patients. Furthermore, a proof-of-concept experiment validates the potential of the probe for diagnosis of HSPN by urine test