Ultrafast Self-Assembly of Zeolitic Imidazolate Framework-8 Enables Antibody Orientation for Ultrasensitive Lateral Flow Immunoassays.

Linker-optimized bivalent nanobodies combined with photothermal gold liposome nanocomposites for enhanced dual-mode lateral flow immunoassay.

Lateral flow immunoassay (LFIA) has been widely used for rapid on-site analysis because of its simplicity, portability, and low cost. However, its performance in competitive assays, particularly for small molecule toxins, remains limited, as the properties of antibodies and the reliance on single-mode signal often lead to insufficient sensitivity and reliability. To address this challenge, we developed an enhanced colorimetric-photothermal LFIA by integrating linker-optimized bivalent nanobodies (BvNbs) and gold-liposome nanocomposites (Au-LNCs). Using tetrodotoxin (TTX) as a representative analyte, a series of BvNbs with different linker lengths were constructed. Molecular docking and molecular dynamics simulations further demonstrated that linker length modulates BvNbs detection performance by regulating conformational stability, local flexibility, and persistent interactions with free target molecules. In parallel, photothermal Au-LNCs were prepared, which exhibited broadband near-infrared absorption and a photothermal conversion efficiency as high as 78.06%. The resulting LFIA achieved a photothermal LOD of 1.89 ng/mL, corresponding to an approximately 10.7-fold improvement in sensitivity compared with conventional colloidal gold-based LFIA, while maintaining good reliability in real samples. Overall, this study provides mechanistic insight into the rational design of BvNbs and a promising strategy for improving LFIA performance.

Boronate-mediated antibody orientation: a molecular simulation-guided strategy for ultra-sensitive lateral flow immunoassays

Interface Self-Assembly of Au10 Nanoclusters for Enhanced Electrochemiluminescence and Alzheimer's Disease Biomarker Detection.

Atomically precise metal nanoclusters (NCs), as ultrasmall materials with well-defined composition and structure, exceptional biocompatibility, and unique optical properties, position them as strong candidates in the field of electrochemiluminescence (ECL). However, the ECL efficiency of NCs is relatively low, which dramatically constrained their applications due to the demands of detection sensitivity and brightness. In this study, we report the interface self-assembly of Au10 nanoclusters for the first time, and ultimately formed a fibrous structure with a high aspect ratio, Au10-Fiber, which is an innovative approach that significantly enhances the ECL activity of Au10 NCs. By employing time-dependent and in situ spectroscopic techniques, we visually monitored the dynamic assembly process, and elucidated the interface self-assembly mechanism mediated by aurophilic interaction and π-π stacking. The increase in local electronic density, enhanced conductivity of the ordered structure, and accelerated electron transfer within the π-conjugated system collectively contributed to the significant enhancement of the ECL performance, thereby revealing the key structural factors responsible for ECL enhancement. As a proof of concept, we successfully constructed an ECL immunosensor based on Au10-Fiber for the detection of Alzheimer's disease biomarker Aβ1-42, achieving a detection limit below 3.33 fg/mL.

Avidin-Functionalized Gold Nanoparticles Enable Cationic Isotachophoresis for Enhanced Lateral Flow Assays.

The LIGMA assay is established as a viable electrokinetic strategy for improving paper-based biosensors, providing a foundation for expanded applications in clinical diagnostics, multiplexed detection, and portable field-deployable biosensing platforms.

Pyrene-Tagged Polyimidazolium Nanoclays Enable Modular Excimer Emission for Multi-Analyte Fluorescence Sensing

We introduce a modular platform for engineering excimer-active fluorescent nanoclays by covalently installing pyrene onto imidazolium-functionalized polyionic nanoclays (PINCs) using thiol-maleimide Michael addition. Precise control of pyrene surface densities (0.1–15 mol %) affords a synthetically tunable monomer–excimer landscape, with systematic shifts in excimer-to-monomer intensity ratios (IE/IM) and solvent-dependent photophysics that confirm periodic probe spacing rather than clustering. The cationic PINC framework dramatically enhances analyte accessibility and local concentration, enabling solution-phase detection of nitroaromatic and nitrate-based explosives with Stern–Volmer constants of up to 1.56 × 104 M–1 for TNT, an order-of-magnitude enhancement over neutral pyrene (Py) controls. Py-PINCs also exhibit strong and selective quenching by halides, highlighting synergistic electrostatic and collisional pathways. In the solid state, PINC-immobilized pyrene functions as an environment-responsive oxygen sensor, displaying linear quenching (KSV = 5.29 bar–1) and a rapid reversible response (2.5 s). These results establish pyrene-tagged PINCs as an attractive class of charge-amplified, excimer-programmable 2D hybrid materials that unify tunable photophysics with multimodal chemical sensing, expanding the functional scope of designer PINCs for security, environmental, and analytical technologies.

Electron-Donating Benzenethiols Direct Rapid Formation of Plasmonic Gold Nanoflowers

Gold nanostructures with branched morphologies exhibit strong plasmonic properties, enabling advanced biosensing and biochemical applications. Here, we report a rapid and scalable synthesis of gold nanoflowers (AuNFs) using modified benzenethiols as both reducing and capping agents. Benzenethiols bearing electron-donating substituents promoted rapid Au3+ reduction and anisotropic branch growth, completing particle formation in less than 10 seconds without seed preparation or organic-aqueous transfer steps. The resulting AuNFs had abundant plasmonic hot spots and intrinsic Raman reporters, serving as dual-modality probes for colorimetry and surface-enhanced Raman scattering (SERS). When integrated into lateral flow assays, AuNFs markedly enhanced analytical sensitivity. In oxycodone detection, limits of detection reached 4.48 pg/mL (colorimetry) and 0.38 fg/mL (SERS), representing 700-fold and 1,200-fold improvements, respectively, over spherical gold nanoparticles. This performance enabled accurate quantification of oxycodone in plasma samples from murine addiction models. The developed method provides a practical route for preparing high-performance plasmonic nanomaterials for applications in biosensing, catalysis, and analytical chemistry.