MicroLED biosensor with colloidal quantum dots and smartphone detection

Abstract

A fluorescence sensor with the capability for spatially multiplexed measurements utilizing smartphone detection is presented. Bioconjugated quantum dots are used as the fluorescent tag and are excited using a blue-emitting microLED (µLED). The 1-dimensional GaN µLED array is butt-coupled to one edge of the glass slide to take advantage of total internal reflection fluorescence (TIRF) principles. The bioassays on the top surface of the glass waveguide are excited and the resultant fluorescence is detected with the smartphone. The red, green, and blue channels of the digital image are utilized to spectrally separate the excitation light from the fluorescence for analysis. Using a biotin-functionalized glass slide as proof of principle, we have shown that streptavidin conjugated quantum dots can be detected down to a concentration of 8 nM.

Biotinylated Photocleavable Semiconductor Colloidal Quantum Dot Supraparticle Microlaser

“…To test the added biocapture and release capabilities of the functionalized SPs, a simple sensor was developed to detect the presence of neutravidin (see Figure ). Glass slides were functionalized with APTES and NHS-biotin . Neutravidin was washed over the substrate, consequently binding to biotin, with any excess washed off.…”

“…Glass slides were functionalized with APTES and NHS-biotin. 36 Neutravidin was washed over the substrate, consequently binding to biotin, with any excess washed off. A control test was run in parallel, where no neutravidin was used.…”

“…The SPs were excited using a 450 nm μLED array which was coupled to a glass slide using the slide as a waveguide, as previously described. 36 The μLED array was operated with a driving current of 120 mA, which corresponds to an irradiance of approximately 1200 μW/cm 2 evanescently interacting with the SPs. The fluorescence was imaged using the camera on a smartphone (Samsung Galaxy S9).…”

Spectral Characterization of a Blue Light-Emitting Micro-LED Platform and Microbial Chromophores for Therapeutic Applications in Skin Conditions

“…In this study, the μLED array was driven at 120 mA (2.94 V) giving an optical power of 10 mW. Details of array design and characterisation can be found elsewhere (30). The μLED array was coupled to a 1 mm x 75 mm x 25 mm glass slide, which guided light within by total internal reflection in an edge-lit configuration, the size of the μLED emission area at the sapphire facet (smaller than the thickness of the slide) ensuring maximisation of the coupling efficiency (Fig.…”

Fabrication of a low-cost benchtop optical imager for quantum dot microarray-based stress biomarker detection

“…Since 1998 quantum dots (QDs) have been established as a new type of fluorophores in biological research. Since then, semiconducting QDs have become important fluorescent probes for in-vivo and in-vitro biosensing and bioimaging [18][19][20]21]. The QDs are promising candidates for detecting biomarkers in a fast, inexpensive, precise and non-invasive manner in the early stages of cancer metastasis.…”