Sensitive and Specific Detection of Carcinoembryonic Antigens Using Toroidal Metamaterial Biosensors Integrated with Functionalized Gold Nanoparticles

Abstract

Carcinoembryonic antigen (CEA) is a biomarker that is highly expressed in cancer patients. Label-free, highly sensitive, and specific detection of CEA biomarkers can therefore greatly aid in the early detection and screening of cancer. This study presents a toroidal metamaterial biosensor integrated with functionalized gold nanoparticles (AuNPs) that demonstrated highly sensitive and specific detection of CEA using terahertz (THz) time-domain spectroscopy. In the biosensor, a closed-loop magnetic field formed an electrical confinement, resulting in a high sensitivity (287.8 GHz/RIU) and an ultrahigh quality factor (15.04). In addition, the integrated AuNPs with high refractive indices significantly enhanced the sensing performance of the biosensor. To explore the quantitative and qualitative detection of CEA, CEA biomarkers with various concentrations and four types of proteins were measured by the designed biosensor, achieving a limit of detection of 0.17 ng and high specificity. Even more significant, the proposed AuNP-integrated THz toroidal metamaterial biosensor demonstrates exceptional potential for use in technologies for cancer diagnosis and monitoring.

A terahertz metasurface biosensor based on electromagnetically induced transparency for fingerprint trace detection

“…Fig. S3 (ESI †) displays fitting transmission spectra with various d using eqn (2). The dependence of the fitting parameter on d is described in Fig.…”

“…Metasurface, exciting various resonance modes, can considerably enhance the interaction between light and matter by artificially manipulating electromagnetic characteristics. [1][2][3][4][5] The frequency shift or amplitude change of resonant peaks or dips has become an effective method to achieve qualitative or quantitative biosensing of trace analytes. Up to now, a variety of methods have been attempted to reach a greater frequency shift or higher Q-factor to improve the sensitivity of meta-sensing.…”

Immunosensor with Enhanced Electrochemiluminescence Signal Using Platinum Nanoparticles Confined within Nanochannels for Highly Sensitive Detection of Carcinoembryonic Antigen

“…As a technique that combines electrochemistry with chemiluminescence, ECL refers to the generation of luminescent species by inducing high-energy electron transfer reactions on the electrode surface through applied voltage. Until now, a luminol-based ECL system that uses luminol as the luminescent reagent and hydrogen peroxide (H 2 O 2 ) as a co-reactant has been widely used in fields such as bioanalysis, environmental testing, and chemical sensing [ 19 , 20 ]. On the one hand, luminol loses a proton to become the luminol anion in an alkaline environment, then undergoes electrochemical oxidation to form the luminol radical.…”

Mercury-Mediated Epitaxial Accumulation of Au Atoms for Stained Hydrogel-Improved On-Site Mercury Monitoring

“…So far, majority of those advanced colorimetric analysis methods were facilitated by the presynthetic plasmonic nanostructures. − Nevertheless, the presynthetic point possesses a lot of deficiency, which strongly restricts the practical performances of plasmonic Au NPs. First, in terms of those analysis methods conducted in homogeneous solutions, the dispersed states of presynthetic Au NPs are highly sensitive to the coexisting environmental impacts when they are used for the target recognition in aqueous phases, adversely affecting practical analytical testing. − To prevent the nonspecific aggregation of Au NPs, researchers usually adopted the procedure of modifying Au NPs with stabilizers, such as small molecules, proteins, , nucleic acids, polymers, and inorganic materials . Although the stability of gold NPs during the storage process was enhanced through chemical/biological coordination, the colorimetric signals of nanoprobes were still slightly influenced when introduced into complex practical samples, such as sewage, serum, and food juices.…”