Au nanoparticles (AuNPs) have been used as signal reporters in colorimetric lateral flow immunoassays (LFAs) for decades. However, it remains a major challenge to significantly improve the detection sensitivity of traditional LFAs due to the low brightness of AuNPs. As an alternative approach, we overcome this problem by utilizing 150 nm gold nanoshells (AuNSs) that were engineered by coating low-density silica nanoparticles with a thin layer of gold. AuNSs are dark green, have 14 times larger surface area, and are approximately 35 times brighter compared to AuNPs. In this study, we used detection of thyroid-stimulating hormone (TSH) in a proof-of-concept assay. The limit of detection (LOD) with AuNS-based LFA was 0.16 µIU/mL, which is 26 times more sensitive than the conventional colorimetric LFA that utilizes AuNP as a label. The dynamic range of the calibration curve was 0.16–9.5 µIU/mL, making it possible to diagnose both hyperthyroidism (5 µIU/mL) using AuNS-based LFA. Thus, the developed device has a strong potential for early screening and diagnosis of diseases related to the thyroid hormone.

A colloidal gold-based lateral flow immunoassay was developed for the rapid quantitative detection of Cystatin-C in serum and whole blood. This device has an assay time of 15 min, making it a convenient point-of-care diagnostic tool. The device has a quantification range spanning from 0.5 to 7.5 µg/mL, with a lower limit of detection at 0.18 µg/mL. To validate its accuracy, the test was compared to a standard nephelometric immunoassay, and the results exhibited a robust linear correlation with an adjusted r² value of 0.95. Furthermore, the device demonstrates satisfactory levels of analytical performance in terms of precision, sensitivity, and interference, indicating its potential for precise Cystatin-C quantification, particularly in renal-failure patients. Notably, the Cystatin-C-LFA device also demonstrates satisfactory stability, as a 30-day accelerated stability study at 50 °C showed no change in the device performance, indicating a long shelf life for the product when stored at room temperature.

This paper presents a plasma display device (PDD) based on laser-induced graphene nanoribbons (LIGNs), which were directly fabricated on polyimide sheets. Superior field electron emission (FEE) characteristics, viz. a low turn-on field of 0.44 V/μm and a large field enhancement factor of 4578, were achieved for the LIGNs. Utilizing LIGNs as a cathode in a PDD showed excellent plasma illumination characteristics with a prolonged plasma lifetime stability. Moreover, the LIGN cathodes were directly laser-patternable. Such superior plasma illumination performance of LIGN-based PDDs has the potential to make a significant impact on display technology.