Construction of an autofluorescence interference-free phosphorescence biosensor for the specific detection of TK1 mRNA.

The anti-interference ability of biosensors is critical for detection in biological samples. Fluorescence-based sensors are subject to interference from self-luminescent substances in biological matrices. Therefore, phosphorescent sensors stand out among biosensors due to their lack of self-luminescence background. In this study, a phosphorescent sensor was constructed, which can accurately detect thymidine kinase 1 (TK1) mRNA in biological samples and avoid autofluorescence interference. When there is no target, polydopamine (PDA) is used as the phosphorescence resonance energy transfer (PRET) acceptor to quench the phosphorescence of the persistently luminescent (PL) nanomaterial. When there is a target, the DNA modified by the PL nanomaterial is replaced by the hairpin H and removed away from the PDA, resulting in a rebound in phosphorescence. The phosphorescent sensor exhibits a good linear relationship in the TK1 mRNA concentration range of 0-200 nM, and the detection limit was 1.74 nM. The sensor fabricated in this study can effectively avoid interference from spontaneous fluorescence in complex biological samples, and sensitively and precisely detect TK1 mRNA in serum samples, providing a powerful tool to more accurately detect biomarkers in biological samples.

Engineering of catalytic hairpin-rigidified Y-shaped DNA-functionalized nanomachine to rapidly detect mRNA.

The catalytic hairpin-rigidified Y-shaped DNA through layer-by-layer assembly has been fixed on the surface of copper sulfide nanoparticles for the detection of survivin mRNA. The distance between the CHA probes fixed on the Y-shaped DNA is significantly shortened. The results show that the fluorescence of this nanomachine reached the maximum value in 50 min (excitation wavelength at 488 nm and emission wavelength 526 nm), and its reaction rate is more than 5-fold faster than that of the free-CHA control system. In addition, the nanomachine showed high sensitivity (LOD of 3.5 pM) and high specificity for the survivin mRNA detection. Given its fast response time and excellent detection performance, we envision that the catalytic hairpin-rigidified Y-shaped DNA-functionalized nanomachine will offer potential applications in disease diagnostics and clinical applications.

pH-activated DNA nanomachine for miRNA-21 imaging to accurately identify cancer cell.

MicroRNA (miRNA) imaging has been employed to distinguish cancer cells from normal cells by exploiting the overexpression of miRNA in cancer. Inspired by the acidic extracellular tumor microenvironment, we designed a pH-activated DNA nanomachine to enable the specific detection of cancer cells using miRNA imaging. The DNA nanomachine was engineered by assembling two hairpins (Y1 and Y2) onto the surface of a ZIF-8 metal-organic framework (MOF), which decomposed under acidic conditions to release the adsorbed DNA hairpin molecules in situ. The released hairpins were captured by the target miRNA-21 and underwent catalytic hairpin assembly amplification between Y1 and Y2. The detection limit for miRNA assays using the DNA nanomachine was determined to be 27 pM, which is low enough for sensitive detection in living cells. Living cell imaging of miRNA-21 further corroborated the application of the DNA nanomachine in the identification of cancer cell.

pH-responsive DNA hydrogels with ratiometric fluorescence for accurate detection of miRNA-21.

DNA hydrogels are powerful candidates for stable and sensitive detection of disease-related nucleic acids. However, the ability to accurately detect is the cornerstone of disease diagnosis. To improve the accuracy of DNA hydrogels for detecting targets, we herein reported the design of pH-responsive DNA hydrogels with ratiometric fluorescence. The DNA hydrogels were prepared from the pH-sensitive ZnO-NH2 and CO-Y-DNA probe assembled by the three complementary strands. With the use of miRNA-21 as the model analyte, the DNA hydrogels were applied to fluorescence ratio detection. Under acidic conditions, the ZnO-NH2 was decomposed, thereby releasing the CO-Y-DNA probe. Target miRNA-21 hybridized to the CO-Y-DNA probe, causing the change of fluorescence ratio between TAMRA and Cy5 that both modified in the CO-Y-DNA probe. The developed DNA hydrogels exhibited high accuracy and sensitivity with a low detection limit to 83 pM. In addition, the DNA hydrogels showed long-term stability against DNase I and GSH.

Predictors of effectiveness of early intervention on children with intellectual disability: a retrospective cohort study.

BACKGROUND: The Taiwanese government has been promoting early intervention to children with intellectual disability for years, but data on its effectiveness are limited. METHODS: We recruited children who were treated for intellectual disability at a teaching hospital and had two IQ tests from 2001 to 2005 and used the difference between the two tests as the indicator of effectiveness. RESULTS: The participants included 23 boys and 13 girls 56.5 ± 5.9 months of age at the first test and 73.4 ± 4.9 months at the second. The IQ increased from 57.0 ± 8.0 to 65.1 ± 12.3 (p < 0.001). Multi-variate regressions showed that a low maternal educational level, male gender, and a younger age at the first test were significant independent predictors of the effectiveness. CONCLUSIONS: Early intervention can improve the IQ of children with intellectual disability, and the earlier the intervention the better. The effectiveness is demonstrable in boys and more prominent in children whose mothers had a low educational level.