Resonance Raman scattering-infrared absorption dual-mode immunosensing for carcinoembryonic antigen based on ZnO@SiO2 nanocomposites

Ultrasensitive and smart trace detection via interface-enhanced multi-phonon resonance Raman scattering

Trace detection technology has important applications in fields such as biomedicine, food safety, and environmental monitoring. However, it currently faces challenges including insufficient sensitivity, low efficiency, and a need for improved personalized services, which seriously hinder the in-depth development and widespread application of trace detection technology. Herein, a metal/semiconductor heterojunction was designed and constructed. The synergistic effects of interfacial charge transfer and interfacial passivation of anion vacancy defect states density were revealed to significantly enhance the intensity of multi-phonon resonance Raman scattering (MRRS) of the semiconductor with an enhancement factor of up to 1.4 × 109. A MRRS detection platform was developed to achieve a detection limit of 8.5 aM for let-7a and a relatively wide linear range from 50 aM to 100 nM. Compared to conventional semiconductor detection platforms, the heterojunction probes reduced the detection limit by three orders of magnitude, and expanded the linear range by five orders of magnitude. Furthermore, the enhanced synergistic effect at the heterojunction interface directly boosts the MRRS signal intensity, significantly lowering the detection limit, and broadening the linear range. To further improve detection efficiency and user experience, this technology was combined with smartphone intelligent analysis software, allowing for rapid reading and intelligent analysis of MRRS data from serum sample, which enhances the speed and accuracy of data processing. This work not only offers a new, ultrasensitive approach to develop trace detection technology, but also makes significant strides in improving personalized services and promoting the advancement of telemedicine.

Sensitive and accurate photoluminescent-multiphonon resonant Raman scattering dual-mode detection of microRNA-21 via catalytic hairpin assembly amplification and magnetic assistance

A novel dual-mode detection method for microRNA-21 was developed. Photoluminescent (PL) and multiphonon resonant Raman scattering (MRRS) techniques were combined by using ZnTe nanoparticles as signal probes for reliable detection. The catalytic hairpin assembly (CHA) strategy was integrated with superparamagnetic Fe3O4 nanoparticle clusters (NCs) to enhance sensitivity. A remarkable detection sensitivity was achieved, with an ultralow limit of detection (LOD) of 310 aM for PL and 460 aM for MRRS. A wide detection range spanning from 500 aM to 100 nM for PL and 500 aM to 10 nM for MRRS was demonstrated, showcasing the versatility and efficacy of the method. Comparing to current methods and our previous work, both sensitivity and detection range showed significant advancements. The consistency between the detection results of PL and MRRS modes highlights the reliability and robustness of our method, offering compelling internal validation. This work not only opens new avenues for achieving sensitive and accurate detection of miRNAs, but also shows significant promise for advancing diagnostic applications in disease management.

Tri-signal CdS@SiO2 nanoprobes for accurate and sensitive detection of human immunoglobulin G with enhanced flexibility and internal validation

Accurate and sensitive determination of human immunoglobulin G (HIgG) level is critical for diagnosis and treatment of various diseases, including rheumatoid arthritis, humoral immunodeficiencies, and infectious disease. In this study, versatile tri-signal probes were developed by preparing CdS@SiO2 nanorods that integrate photoluminescence (PL), multi-phonon resonant Raman scattering (MRRS) and infrared absorption (IRA) properties. Through the coating of multiple CdS nanoparticles as cores within SiO2 shells, the PL and MRRS properties of CdS were improved, resulting in a significantly lowered limit of detection (LOD), with the lowest LOD of 12.37 ag mL-1. Integration with the distinctive IRA property of SiO2 shells widened the detection range towards higher concentrations, establishing a final linear range of 50 ag mL-1 to 10 μg mL-1. The remarkable consistency among the three signals highlighted the robust internal verification capability for accurate detection. This approach enhances flexibility in selecting detection methodologies to suit diverse scenarios, facilitating HIgG detection. The tri-signal nanoprobes also exhibited excellent detection selectivity, specificity and repeatability. This study presents a fresh idea for developing high-performance detection strategies.

Achieving enhanced sensitivity and accuracy in carcinoembryonic antigen (CEA) detection as an indicator of cancer monitoring using thionine/chitosan/graphene oxide nanocomposite-modified electrochemical immunosensor

The current study has focused on electrochemical immunosensing of carcinoembryonic antigen (CEA) employing an immobilized antibody on a thionine, chitosan, or graphene oxide nanocomposite modified glassy carbon electrode (anti-CEA/THi-CS-GO/GCE) as an indicator of cancer monitoring. THi-CS-GO nanocomposites were made using ultrasonication, and analyses of their morphology and crystal structure using SEM, FTIR, and XRD showed that thionine and chitosan molecules were intercalated with stacking interactions with both the top and bottom of GO nanosheets. Electrochemical experiments revealed anti-CEA, THi-CS-GO/GCE to have exceptional sensitivity and selectivity towards CEA compounds. The detection limit value was established to be 0.8 pg/mL when it was discovered that variations in the decrease peak current were directly proportional to the logarithm concentration of CEA over a wide range from 10-3 to 104 ng/mL. Results of testing the immunosensor's application capability for detecting CEA in a sample of human serum show that ELISA and DPV results are very congruent. The produced immunosensor demonstrated adequate immunosensor precision in determining CEA in prepared genuine samples of human serum and clinical applications.

The application of nanoparticles in point-of-care testing (POCT) immunoassays

The Covid-19 pandemic has led to greater recognition of the importance of the fast and timely detection of pathogens. Recent advances in point-of-care testing (POCT) technology have shown promising results for rapid diagnosis. Immunoassays are among the most extensive POCT assays, in which specific labels are used to indicate and amplify the immune signal. Nanoparticles (NPs) are above the rest because of their versatile properties. Much work has been devoted to NPs to find more efficient immunoassays. Herein, we comprehensively describe NP-based immunoassays with a focus on particle species and their specific applications. This review describes immunoassays along with key concepts surrounding their preparation and bioconjugation to show their defining role in immunosensors. The specific mechanisms, microfluidic immunoassays, electrochemical immunoassays (ELCAs), immunochromatographic assays (ICAs), enzyme-linked immunosorbent assays (ELISA), and microarrays are covered herein. For each mechanism, a working explanation of the appropriate background theory and formalism is articulated before examining the biosensing and related point-of-care (POC) utility. Given their maturity, some specific applications using different nanomaterials are discussed in more detail. Finally, we outline future challenges and perspectives to give a brief guideline for the development of appropriate platforms.

Dual-mode biosensor platform based on synergistic effects of dual-functional hybrid nanomaterials

Detection of biomarkers is very vital in the prevention, diagnosis and treatment of diseases. However, due to the poor accuracy and sensitivity of the constructed biosensors, we are now facing great challenges. In addressing these problems, nanohybrid-based dual mode biosensors including optical-optical, optical-electrochemical and electrochemical-electrochemical have been developed to detect various biomarkers. Integrating the merits of nanomaterials with abundant active sites, synergy and excellent physicochemical properties, many bi-functional nanohybrids have been reasonable designed and controllable preparation, which applied to the construction dual mode biosensors. Despite the significant progress, further efforts are still needed to develop dual mode biosensors and ensure their practical application by using portable digital devices. Therefore, the present review summarizes an in-depth evaluation of the bi-functional nanohybrids assisted dual mode biosensing platform of biomarkers. We are hoping this review could inspire further concepts in developing novel dual mode biosensors for possible detection application.

Targeted trapping of endogenous endothelial progenitor cells for myocardial ischemic injury repair through neutrophil-mediated SPIO nanoparticle-conjugated CD34 antibody delivery and imaging

Endothelia progenitor cell (EPC)-based revascularization therapies have shown promise for the treatment of myocardial ischemic injury. However, applications and efficacy are limited by the relatively inefficient recruitment of endogenous EPCs to the ischemic area, while implantation of exogenous EPCs carries the risk of tumorigenicity. In this study, we developed a therapeutic protocol that relies on the capacity of neutrophils (NEs) to target lesions and release preloaded EPC-binding molecules for high efficiency capture. Neutrophils were loaded with superparamagnetic iron oxide nanoparticles conjugated to an antibody against the EPC surface marker CD34 (SPIO-antiCD34/NEs), and the therapeutic efficacy in ischemic mouse heart following SPIO-antiCD34/NEs injection was monitored by SPIO-enhanced magnetic resonance imaging (MRI). These SPIO-antiCD34/NEs exhibited unimpaired cell viability, superoxide generation, and chemotaxis in vitro as well as satisfactory biocompatibility in vivo. In a mouse model of acute myocardial infarction (MI), SPIO-antiCD34 accumulation could be observed 0.5 h after intravenous injection of SPIO-antiCD34/NEs. Moreover, the degree of CD133⁺ EPC accumulation at MI sites was three-fold higher than in control MI model mice, while ensuing microvessel density was roughly two-fold higher than controls and left ventricular ejection fraction was > 50%. Therapeutic cell biodistribution, MI site targeting, and treatment effects were confirmed by SPIO-enhanced MRI. This study offers a new strategy to improve the endogenous EPC-based myocardial ischemic injury repair through NEs mediated SPIO nanoparticle conjugated CD34 antibody delivery and imaging. STATEMENT OF SIGNIFICANCE: The efficacy of endogenous endothelial progenitor cell (EPC)-based cardiovascular repair therapy for ischemic heart damage is limited by relatively low EPC accumulation at the target site. We have developed a method to improve EPC capture by exploiting the strong targeting ability of neutrophils (NEs) to ischemic inflammatory foci and the capacity of these treated cells to release of preloaded cargo with EPC-binding affinity. Briefly, NEs were loaded with superparamagnetic iron oxide nanoparticles conjugated to an antibody against the EPC surface protein CD34 (SPIO-antiCD34). Thus, we explored sites targeting with nanocomposites cargo for non-invasive EPCs interception and therapy tracking. We demonstrate that SPIO-antiCD34 released from NEs can effectively capture endogenous EPCs and thereby promote heart revascularization and functional recovery in mice. Moreover, the entire process can be monitored by SPIO-enhanced magnetic resonance imaging including therapeutic cell biodistribution, myocardial infarction site targeting, and tissue repair.

Enhanced catalytic sulfamethoxazole degradation via peroxymonosulfate activation over amorphous CoSx@SiO2 nanocages derived from ZIF-67

In this work, the amorphous CoS_x@SiO₂ nanocages were hydrothermally synthesized by sulfurizing ZIF-67@SiO₂ in the presence of thioacetamide (TAA). The catalytic performances of CoS_x@SiO₂ nanocages as heterogeneous catalysts to activate peroxymonosulfate (PMS) for the sulfamethoxazole (SMX) degradation were systematically investigated. 100% SMX was degraded within 6 min in CoS_x@SiO₂/PMS system, indicating that the amorphous CoS_x@SiO₂ nanocages exhibited outstanding sulfate radical-advanced oxidation process (SR-AOP) activity toward SMX degradation due to the regeneration of Co²⁺ by surficial sulfur species like S^2-/S₂^2-. The effects of PMS dosages, initial pH, SMX concentrations and co-existing ions on SMX degradation efficiency were explored in detail. The SMX removal efficiency was obviously improved in the simulated wastewater containing chloride ions (Cl^-) and low-concentration bicarbonate ions (HCO₃^-). The residual PMS and the generated sulfate radical (SO₄·^-) were determined quantitatively in CoS_x@SiO₂/PMS system. A possible mechanism in CoS_x@SiO₂/PMS system was proposed based on the results of quenching experiments, X-ray photoelectron spectroscopy (XPS) analysis, electrochemical tests, and electron spin resonance (ESR). The CoS_x@SiO₂ exhibited good stability and reusability, in which 100% SMX removal was achieved even after five consecutive cycles. This work provided a strategy for regulating the stability of cobalt-based catalyst for efficient pollutant degradation by PMS activation.