Novel Electrochemiluminescent Biosensor to Ultrasensitively Detect U94 Gene in Human Herpesvirus 6 Using Metal–Organic Framework-Based Nanoemitters Comprising Iridium(III) Complexes via One-Pot Coordination Reaction Strategy

Abstract

The detection of the U94 gene in human herpesvirus 6 is crucial for early diagnosis of HHV-6 infections, which could induce acute febrile illness in infants. In this work, the first ultrasensitive electrochemiluminescence (ECL) biosensor for detecting U94 gene in Human Herpesvirus 6 was successfully designed by utilizing efficient novel metal–organic framework (MOF)-based ECL nanoemitters comprising iridium­(III) complexes (Ir-ZIF-8-NH2) synthesized via one-pot coordination reaction strategy as an ECL indicator and a target-catalyzed hairpin assembly (CHA) signal amplification strategy. The as-prepared ECL indicator Ir-ZIF-8-NH2 exhibited an approximately 2.7-fold ECL intensity compared with its small molecular analogue of emissive iridium­(III) complex named IrppymIM formed by in situ coordination reaction between iridium­(III) solvent complex and imidazole ligands. In addition, a target-catalyzed hairpin assembly (CHA) strategy was employed to further improve the sensitivity of the proposed ECL biosensor, which demonstrated a wide linear range from 1 fM to 1 μM and the limit of detection as low as 0.113 fM (S/N = 3). Significantly, this biosensor was successfully applied to detect U94 gene in plasmids and real virus samples. The recoveries were in the range of 97.0–109.0% for plasmids and 95.7–107.5% for real virus samples with a relative standard deviation (RSD) of 1.87–2.53%. These satisfactory experimental results from the proposed ECL biosensor in this work would inevitably promote the development of new time/cost-effective and sensitive methods to detect HHV-6 with a major global health threat and substantial burden on healthcare in the future.

Luminescent Metal–Organic Frameworks for Electrochemiluminescent Detection of Water Pollutants

“…As ECL does not require a light source, it simplifies the detection apparatus, and, most importantly, invalidates background signals from scattered light and luminescent impurities, thus providing improved sensitivity. However, some specific ECL configu-rations employing semiconductors and named photo-induced ECL require an excitation light to photo-generate holes and electrons that trigger the emission of ECL [48][49][50]. These properties have resulted in ECL becoming a significant detection method in analytical chemistry and microscopy [23,30,[51][52][53][54][55][56][57][58][59][60].…”

“…The high sensitivity of ECL sensors based on MOF luminophores allows the efficient detection of water pollutants, which are typically present in low amounts in water bodies. This set off the recent development of novel MOF materials for ECL and new applications, especially sensing and imaging [35,39,[44][45][46][47][48][49][50].…”

Renewable Electrochemiluminescence Biosensor Based on Eu-MOGs as a Highly Efficient Emitter and a DNAzyme-Mediated Dual-drive DNA Walker as a Signal Amplifier for Ultrasensitive Detection of miRNA-222

“…Nucleic acid amplification strategies including strand displacement amplification (SDA), catalytic hairpin assembly (CHA), , rolling circle amplification (RCA), hybridization chain reaction (HCR), , etc., are often used to stimulate targets to produce more output DNA for realizing the amplification in the applications of trace detection of tumor markers, , bioimaging, and molecular recognition . Nevertheless, some single nucleic acid amplification strategy always confronts many obstacles like low target conversion efficiency, nonideal amplification effect, and discontinuous reaction progress.…”