A compartmentalization-free electrochemiluminescence (ECL) digital immunoassay based on silica-coated gold nanorod (AuNR@SiO2) for detecting tumor necrosis factor-α secreted by activated T cells and demonstrates promising potential for clinical translation.
Abstract
High-sensitivity cytokine detection is essential for predicting immunotherapy efficacy and monitoring treatment. Conventional methods such as ELISA suffer from limited sensitivity, while single-molecule immunoassays, although highly sensitive, often require physical compartmentalization, resulting in high cost and limited clinical applicability. Herein, we report a compartmentalization-free electrochemiluminescence (ECL) digital immunoassay based on silica-coated gold nanorod (AuNR@SiO2) for detecting tumor necrosis factor-α (TNF-α) secreted by activated T cells. The AuNR@SiO2 nanoparticles served as efficient nanoaccelerators, increasing the ECL photon emission rate of the tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)32+)/tri-n-propylamine (TPrA) system by 17-30-fold. Mechanistic investigations suggest that the enhancement originates from two complementary effects: plasmonic modulation associated with the localized surface plasmon resonance (LSPR) of the AuNR core, and nanoconfinement provided by the mesoporous SiO2 shell, which promotes local enrichment of ECL reactants and increases the effective reaction frequency around individual nanoparticles. Using this platform, TNF-α was detected with approximately one-order-of-magnitude higher sensitivity than conventional ELISA and a wide linear range of 10-50,000 pg/mL. The method also allowed direct analysis of TNF-α in cell culture supernatants without pretreatment, revealing activation-dependent secretion kinetics and confirming a positive feedback circuit in T cell cytokine production. Compared with existing single-molecule immunoassays, this ECL platform eliminates the need for precisely fabricated microchambers or time-consuming signal amplification, enabling straightforward digital readout while remaining compatible with standard immunoassay workflows. This work provides a simple and practical strategy for isolation-free ECL digital immunoassays and demonstrates promising potential for clinical translation.
A dual-mode colorimetric–photothermal LFIA platform was successfully constructed for the detection of thrombosis-related biomarkers, including thrombomodulin and α2-plasmin inhibitor–plasmin complex, in clinical serum samples, enhancing analytical sensitivity and reliability.
Jun Yin, Yu Qiu, Yao Nie et al.· RSC Advances· 0 citations
Early and multiplex detection of Alzheimer’s disease (AD) biomarkers is essential for timely diagnosis and accurate disease staging; however, conventional immunoassays lack the sensitivity and multi-channel capability required to quantify extremely low-abundance proteins in complex biological matrices. In this work, we present a novel triple-target electrochemiluminescence (ECL) biosensor based on magnetic metal–organic frameworks (MMOFs) integrated with quantum-dot (QD)–mediated resonance energy transfer (RET) for the simultaneous detection of three clinically significant AD biomarkers: Amyloid Precursor Protein (APP), Clusterin, and Glial Fibrillary Acidic Protein (GFAP). The MMOF platform provides a high-surface-area, magnetically responsive scaffold that enables efficient immobilization of primary antibodies, while MoS₂ QDs, carbon quantum dots (CQDs), and CdSe/ZnS QDs act as spectrally distinct RET acceptors, facilitating clean and interference-free multiplexed ECL readout from a single TCPO-triggered excitation event. Under optimized analytical conditions, the biosensor displayed strong, concentration-dependent ECL responses across a wide dynamic range (40 ng/mL down to 0.0004 ng/mL). The calculated limits of detection demonstrated excellent sensitivity, achieving 0.67 pg/mL for APP, 0.92 pg/mL for Clusterin, and 0.54 pg/mL for GFAP, confirming the platform’s capability to quantify trace-level biomarkers far below their physiological concentrations. This remarkable performance arises from the highly efficient CRET mechanism between TCPO high-energy intermediates and the QD emitters, further enhanced by the synergistic dual co-reactant system (H₂O₂/APS).
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Muhammad Faizan, Chi-Hsien Liu· ECS Meeting Abstracts· 0 citations
A novel, enzyme-free surface-enhanced Raman scattering (SERS) platform based on a "dual-hotspot amplification" strategy that enhances detection sensitivity but also provides a useful design concept for the ultrasensitive analysis of carbohydrate-derived biomarkers.
Meiqi Bao, Xiaoyan Ma, Hongcai Liu et al.· Biosensors & bioelectronics· 0 citations
It has been highly challenging to reliably detect various cancers at an early stage when tumors are just millimeters in size. To address this, we developed a tumor microenvironment (TME)-responsive nanoprobe, PR-KAd@CD-AuNC, enabling cross-validated cancer detection through in vivo second near-infrared (NIR-II) fluorescence imaging and in vitro colorimetric urinalysis. The nanoprobe consists of three integrated components: a renal-clearable signal-output segment (cyclodextrin-functionalized gold nanocluster, CD-AuNC), a tumor-targeting and size-controlling component (PR), and a matrix metalloproteinase-2 (MMP2)-cleavable linker (KAd). PR, composed of 8-arm poly(ethylene glycol) for prolonged circulation and c(RGDfK) peptides for αvβ3 integrin targeting, directed selective tumor accumulation after intravenous injection of PR-KAd@CD-AuNC. The intrinsic emission of CD-AuNC above 1100 nm enabled high-resolution, real-time NIR-II fluorescence imaging with attenuated photon scattering, allowing precise tumor delineation. Within the TME, specifically overexpressed MMP2 cleaved the KAd linker, releasing ∼2 nm CD-AuNC fragments from the ∼10 nm parent nanoprobe. Being smaller than the ∼5.5 nm renal filtration threshold, these fragments were renally excreted. Concurrently, the peroxidase-like activity of CD-AuNC catalyzed tetramethylbenzidine oxidation to produce a visible blue signal, providing a simple and low-cost urinalysis method suitable for broad cancer screening applications. This dual-modality strategy effectively distinguished cancers from inflammation and other diseases, detecting small tumors for multiple cancer types with a sensitivity surpassing that of computed tomography (CT) imaging, which makes it a promising early detection approach. Furthermore, it was also employed to dynamically assess cancer therapeutic efficacy (i.e., immunotherapy, chemotherapy, and surgical resection), suggesting clinical value for guiding treatment decisions.
Fangyan Ouyang, Huihuang Xiong, Dan Ding et al.· Journal of the American Chem...· 0 citations
This programmable dual-aptamer amplified luminescent proximity homogeneous assay (AlphaLISA) provides a rapid, homogeneous, and highly adaptable strategy for tumor-derived sEVs analysis, offering promising potential for noninvasive cancer diagnostics.