We demonstrate an ultrahigh sensitivity silicon photonic biosensor based on cascaded Mach-Zehnder interferometer (MZI) and ring resonator with the Vernier effect using wavelength interrogation. Experimental results show that the sensitivities reached 2870 nm/RIU and 21,500 nm/RIU for MZI sensor and MZI-ring sensor, respectively. A biosensing application was demonstrated by monitoring the interaction between goat and antigoat immunoglobulin G (IgG) pairs. The measured results show that 1 ng/ml IgG resulted in 0.035 nm and 0.5 nm wavelength shift for MZI sensor and MZI-ring sensor, respectively. This high performance sensor is promising for medical diagnostic applications.
We report ultrasensitive and highly selective detection of testosterone based on microring resonance sensor using molecularly imprinted polymers (MIP). A silicon-on-insulator (SOI) micoring resonator was modified by MIP films (MIPs) on a surface. The MIPs was synthesized by thermopolymerization using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as crosslinking agent. The concentration of detected testosterone varies from 0.05 ng/mL to 10 ng/mL. The detection limit reaches 48.7 pg/mL. Ultrahigh sensitivity, good specificity and reproducibility have been demonstrated, indicating the great potential of making a cost effective and easy to operate lab-on-Chip and down scaling micro-fluidics devices in biosensing.
Background: To investigate the value of carcinoembryonic antigen (CEA), cytokeratin 19 fragment (CYFRA21-1), squamous cell carcinoma antigen (SCC-Ag), and gastrin-releasing peptide (pro-GRP) in the differential diagnosis of lung cancer.
Methods:We enrolled 120 patients with malignant lung cancer who were treated at our hospital between June 2018 to June 2020. A further 58 patients with benign lung tumors and 60 healthy volunteers were also enrolled. Serum levels of CEA, CYFRA21-1, SCC-Ag, and pro-GRP were determined and compared across different populations, different pathological types, and different TNM stages. An ROC curve was drawn to evaluate the value of the four indicators when combined for the diagnosis of lung cancer.Results: The levels of CEA, CYFRA21-1, SCC-Ag, and pro-GRP in the malignant group were significantly higher than those in the benign and healthy groups (P<0.05). CEA in adenocarcinoma was significantly higher than that in squamous cell carcinoma (SCC) and small cell carcinoma (P>0.05), and CYFRA21-1 in non-small cell carcinoma was significantly higher than that in small cell carcinoma (P<0.05).Pro-GRP in small cell carcinoma was significantly higher than that in non-small cell carcinoma (P<0.05), and the SCC-Ag level in SCC was significantly higher than that in small cell carcinoma and adenocarcinoma (P<0.05). There was no statistically significant difference in CEA among various pathological types (P>0.05).However, there were significant differences in the levels of CEA and pro-GRP in different TMN stages (P<0.05), and in the levels of CEA and pro-GRP in different TMN stages (P<0.05) where from stage I to stage IV CEA, pro -GRP levels increased. There was a significant difference in CYFRA21-1 levels in stages I-III (P<0.05), and in stages III and IV, although there was no statistically significant difference in SCC-Ag in different stages (P>0.05). The area under the curve (AUC) for the combined diagnosis of lung cancer with the four markers was 0.9250 (95% CI: 0.8866-0.9634), the sensitivity was 93.29%, and the specificity was 84.32%.Conclusions: Joint inspection of CEA, CYFRA21-1, SCC-Ag, and pro-GRP levels has certain clinical value for the differential diagnosis of lung cancer.
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