Aug 2026· Analytical Methods· 0 citations· 37 references
Medicine
TL;DR
A label-free, rapid, and cost-effective platform offering a highly promising tool for point-of-care carcinoid screening and neuroendocrine biomarker monitoring, functionalized with in situ grown gold nanoflowers (AuNFs).
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) is a critical biomarker for carcinoid tumor diagnosis, yet its precise quantification in clinical settings remains challenging. Herein, we develop a high-performance optical fiber localized surface plasmon resonance (LSPR) biosensor functionalized with in situ grown gold nanoflowers (AuNFs). The hierarchical branched architecture of AuNFs concentrates electromagnetic fields into dense nanoscale "hotspots", delivering a ∼2.2-fold signal amplification compared to spherical AuNPs. Integrated with a specific 5-HT aptamer, the sensor achieves a wide linear range (10-1000 ng mL-1) and a low limit of detection (7.06 ng mL-1), seamlessly covering physiological to pathological concentrations. Validation in human serum confirms excellent accuracy with recoveries of 99.9-102.9%. This label-free, rapid, and cost-effective platform offers a highly promising tool for point-of-care carcinoid screening and neuroendocrine biomarker monitoring.
Dopamine (DA) is an essential neurochemical marker, yet its reliable quantification in complex biofluids remains challenging for fiber-based sensors due to limited signal return and bio-interference. Here, we present a MOF-SERS hybrid architecture integrated onto a fiber-optic probe for DA detection in human plasma. The platform employs polyhedral Au@Ag nanostars coated with an ultrathin MIL-100(Fe) shell, enabling synergistic plasmonic amplification and molecular enrichment at the sensing interface. This engineered interface delivers a high SERS enhancement factor of 3.2 × 108, an ultralow detection limit of 1.22 × 10-10 M, and excellent linearity (R2 = 0.988), while maintaining selectivity against competing neurotransmitters. Importantly, this system enables direct, quantification of DA in human plasma, demonstrating practical applicability in real samples, not previously reported, yielding physiologically relevant concentrations (1.43 × 10-9 M). These results establish the MOF-SERS-integrated fiber probe as a potential powerful platform for remote and flexible neurochemical sensing in complex biological matrices, with strong promising for clinically relevant bioanalysis.
This work introduces a dual-modality analytical platform based on laser-induced graphene (LIG) for the label-free, noninvasive detection of the prostate cancer biomarker sarcosine in human urine. The tunable porosity and high conductivity of LIG enable its bifunctional application as both a sensitive electrochemical electrode and an efficient matrix for laser desorption/ionization mass spectrometry (LDI-MS). Functionalized with sarcosine oxidase and gold nanoparticles (AuNPs), the platform leverages the strengths of both modalities: the AuNPs/LIG electrode provides rapid electrochemical screening with a low limit of detection (LOD) of 2 μM, while the LDI-MS modality offers highly selective, matrix-free confirmation with an enhanced ultralow LOD of 500 nM. Both modalities share a wide linear range (5-50 μM), falling well below the clinical urinary threshold of 20 μM. By combining speed and simplicity from electrochemical sensing with the high sensitivity and molecular specificity of MS analysis on a single device, this platform demonstrates the orthogonal capabilities of LIG for robust, pretreatment-free cancer biomarker diagnostics.
Osteosarcoma monitoring lacks highly sensitive and portable molecular detection methods, creating an urgent clinical need. This study develops a highly sensitive and portable biosensing platform (M-Needle-AuNPs-MXene-EC) integrating flexible microneedle (M-Needle) sampling, gold nanoparticle-titanium carbide (AuNPs-MXene) synergistic signal amplification, and electrochemical (EC) detection for precise quantification and visual dynamic monitoring of microRNA-181b (miR-181b) in osteosarcoma tissues. The platform utilizes microneedle arrays for minimally invasive tissue sample extraction and employs AuNPs-MXene composites to significantly enhance the sensing interface conductivity and biomolecule loading capacity. Experimental results show that the conductivity of the AuNPs-MXene composite (10.9 ± 1.1 S/cm) is nearly nine times higher than that of the Ti3AlC2 MAX phase (1.2 ± 0.12 S/cm). Under optimal conditions, the sensor achieves a linear detection range for miR-181b from 1 aM to 100 pM, with a detection limit as low as 0.34 aM, and exhibits favorable selectivity, high reproducibility and long-term stability of up to 60 days. The integrated visual interface enables real-time monitoring of the detection process and intuitive output of results. Validation using clinical tissue samples demonstrates that the platform can effectively distinguish between osteosarcoma patients and normal controls (p < 0.05), with an area under the receiver operating characteristic curve (AUC) of 0.889. This integrated platform combines minimally invasive sampling, efficient signal amplification, and visual detection, offering a novel point-of-care tool for dynamic monitoring of osteosarcoma.
Zhong-Sheng Zhu, Hui Zhang, Changchun Lu et al.· Frontiers in Bioengineering...· 0 citations
Fiber-optic biosensors based on interferometric structures have attracted considerable attention for rapid and label-free biomarker detection; however, achieving high sensitivity while maintaining practical applicability in complex biological matrices remains challenging. Here, we develop a tapered seven-core fiber (TSCF)-based interferometric biosensor for highly sensitive detection of serum folate. The TSCF cascade architecture generates multiple coupled interference peaks within a compact spectral window, enabling multi-point spectral validation and enhanced evanescent-field interaction. Combined with covalent immobilization of folate-binding protein (FBP) as the recognition layer, the optimized sensor exhibits a refractive-index sensitivity of 1352.1 nm/RIU and a folate sensitivity of 0.118 nm/(ng/mL), achieving a limit of detection of 0.75 ng/mL with a rapid 5-min assay time. The sensor shows excellent linearity (R2 > 0.98) across the range of 0-50 ng/mL and reliable regeneration capability over multiple cycles. Furthermore, quantitative analysis of ten clinical serum samples demonstrates strong concordance with a commercial chemiluminescence assay, demonstrating reliable analytical performance in complex matrices. This work expands tapered multicore fiber interferometry toward label-free small-molecule metabolite quantification, offering a cost-effective platform for clinical folate monitoring.
Unknown authors· Talanta: The International J...· 0 citations
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
We report the first optoelectronic biosensor that employs plasmonic hot carriers for signal transduction. Hot‐carrier generation and transfer were driven by plasmonic hot spots formed through biomarker‐mediated attachment of gold nanoparticles to a gold film. As proof of concept, a device was developed for quantitative detection of 17β‐estradiol (E2), a key biomarker for early diagnosis of precocious puberty in pediatric patients. The sensor enabled ultrasensitive detection of trace E2, even in human urine, with a limit of detection of ≈13 aM (3.5 ag/mL), to the best of our knowledge, the lowest reported to date. In contrast to conventional plasmonic biosensors based on local refractive index change, which are inherently limited for low‐molecular‐weight analytes, this platform uses plasmon‐generated hot carriers and thus achieves ultrahigh sensitivity for small molecules such as E2 (≈272 Da). These results establish plasmonic hot carriers as a promising transduction mechanism for scalable and multiplexed bio‐ and chemical sensing platforms.
T. Nguyen, Heongkyu Ju, Seon Seok Joo et al.· Advanced Functional Material...· 0 citations
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