Hydrogel-Embedded Quantum Dot–Transcription Factor Sensors for Quantitative Progesterone Detection

Abstract

Immobilization of biosensors in or on a functional material is critical for subsequent device development and translation to wearable technology. Here, we present the development and assessment of an immobilized quantum dot− transcription factor−nucleic acid complex for progesterone detection as a first step toward such device integration. The sensor, composed of a polyhistidine-tagged transcription factor linked to a quantum dot and a fluorophore-modified cognate DNA, is embedded within a hydrogel as an immobilization matrix. The hydrogel is optically transparent, soft, and flexible as well as traps the quantum dot−transcription factor DNA assembly but allows free passage of the analyte, progesterone. Upon progesterone exposure, DNA dissociates from the quantum dot−transcription factor DNA assembly resulting in an attenuated ratiometric fluorescence output via Forster resonance energy transfer. The sensor performs in a dose-dependent manner with a limit of detection of 55 nM. Repeated analyte measurements are similarly successful. Our approach combines a systematically characterized hydrogel as an immobilization matrix and a transcription factor−DNA assembly as a recognition/transduction element, offering a promising framework for future biosensor devices.

Hydrogels and Their Role in Biosensing Applications

“…[155] Further composite material approaches include the integration of micro-or nanoparticles into the hydrogel matrix and the addition of fluorescent or chromogenic components for optical detection. [148,[156][157][158] Many bioreceptors were immobilized into or onto the matrix for the detection of a specific target. Such bioassays have wide applications as diagnostic tools in healthcare, and they have traditionally been performed by laboratory methods (e.g., PCR or ELISA).…”

Hydrogel-Based Sensor Networks: Compositions, Properties, and Applications—A Review

“…QD technology was linked with biological detectors such as transcription factor nucleic acids inside hydrogels for the registration of progesterone detection. 385 QD-based Forster resonance energy transfer (FRET) sensors were created by immobilization of CdSe/CdS/ZnS QDs tagged with polyhistidine transcription factors.…”

Review on Colloidal Quantum Dots Luminescent Solar Concentrators

“…The color conversion properties of QDs lead to their application in high‐efficiency LEDs [37–43] . The stability of QDs also promotes their use as bio and inorganic sensors [44–49] . Various nanoparticles such as CdSe, PbS, CdS, AgInS, Si, and C have been frequently studied for their optical and physical properties, specifically for LSC applications [50–57] .…”