The low-potential electrochemiluminescence (ECL) sensors based on cathodic light emission of luminol have caused more and more concerns due to their good stability and reproducibility. In this work, ...highly porous platinum (Pt) nanostructures on ionic liquid functionalized graphene film (GR-IL/pPt) were prepared as platform to construct a label-free ECL sensor for the detection of carcinoembryonic antigen (CEA). Due to their good biocompatibility, excellent electrocatalytic activity and highly porous structure, the as-prepared GR-IL/pPt composites benefited amplified cathodic ECL signal of luminol and high loading density of the CEA antibody. After CEA was incubated with the CEA antibody, the cathodic ECL signal of luminol decreased thanks to the less conductive immunocomplex. The proposed ECL immunosensor realized high sensitivity for CEA detection with a wide linear range from 0.001 fg mL−1 to 1 ng mL−1 and an extremely low detection limit of 0.0003 fg mL−1 (S/N = 3). Moreover, the sensor showed good specificity, stability and reproducibility, indicating that the provided strategy had a promising potential in clinical detection.
•An ECL immunosensor was constructed based on a strong cathodic ECL of luminol.•Highly porous Pt amplified the cathodic ECL of luminol and enhanced the loading amount of anti-CEA.•The developed ECL immunosensor exhibited an extremely low detection limitation and a wide linear range.
A versatile label-free electrochemical biosensor based on dual enzyme assisted multiple amplification strategy was developed for ultrasensitive detection of circulating tumor DNA (ctDNA). The ...biosensor consists of a triple-helix molecular switch (THMS) as molecular recognition and signal transduction probe, ribonuclease HII (RNase HII) and terminal deoxynucleotidyl transferase (TdT) as dual enzyme assisted multiple amplification accelerator. The presence of target ctDNA could open THMS and trigger RNase HII-assisted homogenous target recycling amplification to produce substantial signal transduction probe (STP). The released STP hybridized with the capture probe immobilized on a gold electrode, then TdT and assistant probe were further employed to fulfill TdT-mediated cascade extension and generate stable DNA dendritic nanostructures. The electroactive methyl blue (MB) was finally used as the signal reporter to realize the multiple electrochemical amplification ctDNA detection as the amount of MB is positively correlated with the target ctDNA. Combined with the efficient recognition capacity of the designed THMS and the excellent multiple amplification ability of RNase HII and TdT, the constructed sensing platform could detect KRAS G12DM with a wide detection range from 0.01 fM to 1 pM, and the limit of detection as low as 2.4 aM. Besides, the platform is capable of detecting ctDNA in biological fluid such as plasma. More importantly, by substituting the loop of THMS with different sequences, this strategy could be conveniently expanded into the detection of other ctDNA, showing promising potential applications in clinical cancer screening and prognosis.
•A versatile label-free electrochemical biosensor is developed based on dual enzyme assisted multiple amplification strategy.•The biosensor can detect target ctDNA down to aM level with a dynamic range spanning 5 orders of magnitude.•The biosensor can directly detect target ctDNA in biological fluid such as plasma.•The detection platform can be readily extended to detect a wide range of ctDNA by substituting the loop of THMS.
•An ESCL aptamer sensor was constructed based on dsDNA templated Cu NCs.•The obtained Cu NCs could distinctly enhance the ECL signal of luminol.•The developed ESCL immunosensor exhibited a low ...detection limitation and a wide linear range.
As a new type of nano-catalytic material, copper nanoclusters (Cu NCs) have received more and more attention in various fields such as biosensors and catalysis. In this work, an electrochemical stripping chemiluminescent (ESCL) aptamer sensor based on Cu NCs was constructed for the detection of carcinoembryonic antigen (CEA). The Cu NCs were generated using DNA duplex (the CEA aptamer and its complementary strand) as template. During the ESCL detection process, Cu NCs catalyzed the reduction of H2O2 and were gradually electrochemically oxidized to Cu2+, which both promoted the decomposition of H2O2 and thus greatly improved the ECL of luminol. CEA could specifically bind with its aptamer, so the DNA duplex was damaged, causing a decrease of Cu NCs and lower ECL signals. Under the optimized conditions, the sensor achieved a high sensitivity detection of CEA with a linear range of 0.2 fg mL−1 to 1 ng mL−1 and a detection limit of 66.67 ag mL−1 (S/N = 3). In addition, the sensor exhibited good specificity, stability and reproducibility, and the detection of actual samples obtained satisfactory results, indicating that the provided strategy has potential application prospects in clinical detection.
Early finding of pathogens is significant to avoid foodborne diseases. Here, a novel lab-in-centrifugal-tube colorimetric biosensor was reported for Salmonella typhimurium detection using immune ...nickel nanowires (NNWs) to form capture nets for specific bacterial separation, gold@platinum nanozymes (GPNs) to mark target bacteria for effective signal amplification, and a smartphone App to analyze color change for quantitative bacterial determination. A 3D-printed cylindrical magnetic separator with air pressure self-regulating structure and NNW capture nets was elaboratively constructed and assembled inside the disposable centrifuge tube to simply perform the bacterial separation, label, wash, coloration and detection. Under optimal conditions, Salmonella typhimurium could be quantitatively detected in 2 h with a low detection limit of 21 CFU/mL. The recovery of target bacteria in spiked pork samples ranged from 87.0% to 97.6% with the averaged recovery of 93.9%. This biosensor was Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable to end-users (ASSURED), and had shown the potential for point-of-care testing of foodborne pathogens to ensure food safety.
Background:
The risk of second primary cancers (SPC) is increasing after the first primary cancers (FPC) are diagnosed and treated. The underlying causal relationship remains unclear.
Methods:
We ...conducted a pan-cancer association (26 cancers) study in the Surveillance, Epidemiology, and End Results (SEER) database (non-Hispanic whites). The standardized incidence ratio (SIR) was estimated as the risk of SPCs in cancer survivors based on the incidence in the general population. Furthermore, the causal effect was evaluated by two-sample Mendelian Randomization (MR, 13 FPCs) in the UK Biobank (UKB, n=459,136,, European whites) and robust analysis (radial MR and Causal Analysis Using Summary Effect estimates, CAUSE).
Results:
We found 11 significant cross-correlations among different cancers after harmonizing SIR and MR results. Whereas only 4 of them were confirmed by MR to have a robust causal relationship. In particular, patients initially diagnosed with oral pharyngeal cancer would have an increased risk of non-Hodgkin lymphoma (SIR
SEER
= 1.18, 95%Confidence Interval CI:1.05–1.31, OR
radial-MR
=1.21, 95% CI:1.13–1.30, p=6.00 × 10
-3
; OR
cause
= 1.17, 95% CI:1.05–1.31, p=8.90 × 10
-3
). Meanwhile, ovary cancer was identified to be a risk factor for soft tissue cancer (SIR
SEER
= 1.72, 95%Confidence Interval CI:1.08–2.60, OR
radial-MR
=1.39, 95% CI:1.22–1.58, p=1.07 × 10
-3
; OR
cause
= 1.36, 95% CI:1.16–1.58, p=0.01). And kidney cancer was likely to cause the development of lung cancer (SIR
SEER
= 1.28, 95%Confidence Interval CI:1.22–1.35, OR
radial-MR
=1.17, 95% CI:1.08–1.27, p=6.60 × 10
-3
; OR
cause
= 1.16, 95% CI:1.02–1.31, p=0.05) and myeloma (SIR
SEER
= 1.54, 95%Confidence Interval CI:1.33–1.78, OR
radial-MR
=1.72, 95% CI:1.21–2.45, p=0.02; OR
cause
= 1.49, 95% CI:1.04–2.34, p=0.02).
Conclusions:
A certain type of primary cancer may cause another second primary cancer, and the profound mechanisms need to be studied in the future.
Funding:
This work was in supported by grants from National Natural Science Foundation of China (Grant No. 81972645), Innovative research team of high-level local universities in Shanghai, Shanghai Youth Talent Support Program, intramural grant of The University of Hong Kong to Dr. Rong Na, and Shanghai Sailing Program (22YF1440500) to Dr. Da Huang.
Better cancer treatment and early detection have increased survival rates among patients with cancer. But some cancer survivors can develop a second cancer called a second primary cancer. Second primary cancers may occur months or years after successful treatment of the primary cancer. They are not caused by the spread of the original tumor like a cancer metastasis. Instead, they appear to occur independently in another location or tissue.
Scientists are trying to understand what causes second primary cancers. Genetics, lifestyle, the environment, treatments used for the initial tumor, or other factors may all contribute to individuals developing a second cancer. Learning more about who is at risk of developing a second cancer and why, may lead to new prevention, treatment or screening strategies.
Ruan, Huang et al. found that people with some primary cancers have an increased risk of secondary primary cancers in specific tissues. The researchers first looked at the Surveillance, Epidemiology, and End Results (SEER) database that tracks US cancer patients to see if different types of cancers were more likely to lead to a second primary cancer. Then, the team conducted a comprehensive analysis for a causal relationship in a second extensive health database, the UK Biobank, to determine if the primary cancers may have caused the second primary cancer. The study showed that patients diagnosed with mouth or throat cancers were at increased risk of later developing a lymph node cancer called non-Hodgkin lymphoma. Patients diagnosed with ovarian cancer were at increased risk of later developing cancer in one of the body's soft tissues. Kidney cancer is likely the cause of later lung cancers and a type of blood cancer called myeloma.
Understanding the relationships between an initial and later cancer diagnosis is essential to improve cancer survivors' care. It is especially important for patients diagnosed early in life. More studies are needed to confirm the links Ruan, Huang et al. identified and to understand the mechanism. If more studies confirm the associations, physicians may want to screen survivors for specific cancers. Scientists may also be able to use the information to develop new strategies to help prevent or treat secondary primary cancers.
A sensitive and enzyme-free electrochemical aptasensor was constructed for the sensing of 8-hydroxy-2'-deoxyguanosine (8-OH-dG). In the process of constructing the aptasensor, triple signal ...amplification strategies were introduced to enhance the sensitivity. First, every aptamer/pDNA complex immobilized on magnetic beads could release three kinds of pDNAs when 8-OH-dG was introduced, which caused three-fold magnification of the target. Second, the released three kinds of pDNAs initiated catalyzed hairpin assembly between two hairpin DNAs (HP1 and HP2) on a gold electrode. Meanwhile, the three kinds of pDNAs were released again by a strand displacement reaction to obtain the next catalyzed hairpin assembly. Third, the emerging toehold of HP2 further induced a hybridization chain reaction (HCR) between two hairpin DNAs (HP3 and HP4), forming a long double-stranded DNA concatemer on the surface of the electrode. Finally, Ru(NH
)
, an electroactive cation, was adsorbed onto the long dsDNA concatemer by electrostatic interactions and consequently, an electrochemical signal was generated. Under this triple signal amplification, a low detection limit down to 24.34 fM has been obtained for 8-OH-dG determination, which is superior to those of most previously reported methods.
Dual-potential ratiometric electrochemiluminescence (ECL) is in favor of resistance to environmental interference. However, two kinds of emitters or coreactants, and a wide scan potential range ...(>2 V) are mandatory. This work developed a new dual-potential ratiometric ECL sensor for detection of carcinoembryonic antigen (CEA) using single emitter (luminol) and single coreactant (H2O2) with a mild potential range from −0.1 to 0.6 V. Luminol could produce a strong cathodic ECL (Ec) induced by hydroxyl radicals (HO‧) from the reduction of H2O2, and a relatively weak anodic ECL (Ea). After the ferrocene modified CEA aptamer (Apt-Fc) was attached, Fc could promote Ea by catalyzing the oxidation of H2O2, and reduce Ec by consuming HO‧. With the cycling amplification of the exonuclease I, CEA could substantially reduce the amount of Apt-Fc, resulting in the decrease of Ea and the rise of Ec. So, the ratio of Ec to Ea (Ec/Ea) was used as the detection signal, realizing the sensitive determination of CEA from 0.1 pg mL−1 to 10 ng mL−1 with a LOD of 41.85 fg mL−1 (S/N = 3). The developed sensor demonstrated excellent specificity, stability and reproducibility, with satisfactory results in practical detection.
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•A ratiometric ECL sensor was constructed based on single emitter and single coreactant.•The detection signal of Ec/Ea was independent of the self-decomposition of H2O2.•The ratiometric sensor showed superior sensitivity and accuracy than the single-signal sensors.•The triggered potential range was mild ranging from −0.1 to 0.6 V, preventing the side effects.
The strong interaction between a typhoon and ocean air is one of the most important forms of typhoon and sea air interaction. In this paper, the daily mean sea surface temperature (SST) data of ...Advanced Microwave Scanning Radiometer for Earth Observation System (EOS) (AMSR-E) are used to analyze the reduction in SST caused by 30 westward typhoons from 1998 to 2018. The findings reveal that 20 typhoons exerted obvious SST cooling areas. Moreover, 97.5% of the cooling locations appeared near and on the right side of the path, while only one appeared on the left side of the path. The decrease in SST generally lasted 6–7 days. Over time, the cooling center continued to diffuse, and the SST gradually rose. The slope of the recovery curve was concentrated between 0.1 and 0.5.
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