Hyperbolic-Metamaterials-Based SPR Temperature Sensor Enhanced by a Nanodiamond-PDMS Hybrid for High Sensitivity and Fast Response.

A high-performance surface plasmon resonance (SPR) fiber sensor is proposed with hyperbolic metamaterials (HMMs), nanodiamonds (NDs), and polydimethylsiloxane (PDMS) to enhance the temperature sensitivity and response time. The HMM with tunable dispersion can break through the structural limitations of the optical fiber to improve the refractive index (RI) sensitivity, while NDs and PDMS with large thermo-optic coefficients enable to induce significant RI change under varied thermal fields. The ternary composite endows the sensor with a high temperature sensitivity of -9.021 nm/°C, which is 28.6 times higher than that of the conventional gold film-based SPR sensor. Furthermore, NDs with high thermal conductivity (2200 W/mK) effectively expedite the thermal response of PDMS, which reduces the response time from 80 to 6 s. It is believed that the proposed sensors with high sensitivity, fast response time, and compact size have great potential for applications in industrial production, healthcare, environmental monitoring, etc.

A dual identification strategy based on padlock ligation and CRISPR/Cas14a for highly specific detection of BRAF V600E mutation in clinical samples.

BRAF V600E mutation is a single-nucleotide variation (SNV) that is widely found in various cancers and has been demonstrated to have a strong association with the prognosis and development of some diseases. Thus, we developed a strategy based on rolling circle amplification (RCA) and CRISPR/Cas14a to meet the great need for detecting highly specific BRAF V600E mutation in fine-needle biopsy samples. In this study, a padlock probe was designed to recognize and trigger subsequent ligase chain reactions (LCR). And due to the Taq DNA ligase, a great number of ligated annular padlock probes were generated in the presence of BRAF V600E mutation, subsequently generating long repeated single-strand DNA by RCA. The obtained amplicons were activators triggering the trans-cleavage of CRISPR/Cas14a. CRISPR/Cas14a shows outstanding performance in identifying ssDNA with single base mutation, which significantly increases the specificity of mutation discrimination. Under the optimal conditions, our strategy can identify BRAF V600E mutation down to 0.307 fM with a wide linear range from 1 fM to 10 pM. On the other hand, the dual identification strategy endows the method with terrific specificity for the detection of SNV. Furthermore, our method has been successfully employed to identify BRAF V600E mutation in clinical fine-needle aspiration samples, proving great potential for ultra-specific identification of low abundance BRAF V600E mutation and providing a novel method for diagnosis and treatment of cancer.

MoS2-nanoflower enhanced programmable adsorption/desorption plasmonic detection for bipolar-molecules with high sensitivity.

High sensitivity and capturing ratio are strongly demanded for surface plasmon resonance (SPR) sensors when applied in detection of small molecules. Herein, an SPR sensor is combined with a novel smart material, namely, MoS2 nanoflowers (MNFs), to demonstrate programmable adsorption/desorption of small bipolar molecules, i.e., amino acids. The MNFs overcoated on the plasmonic gold layer increase the sensitivity by 25% compared to an unmodified SPR sensor, because of the electric field enhancement at the gold surface. Furthermore, as the MNFs have rich edge sites and negatively charged surfaces, the MNF-SPR sensors exhibit not only much higher bipolar-molecule adsorption capability, but also efficient desorption of these molecules. It is demonstrated that the MNF-SPR sensors enable controllable detection of amino acids by adjusting solution pH according to their isoelectric points. In addition, the MNFs decorated on the plasmonic interface can be as nanostructure frameworks and modified with antibody, which allows for specific detection of proteins. This novel SPR sensor provides a new simple strategy for pre-screening of amino acid disorders in blood plasma and a universal high-sensitive platform for immunoassay.

One-Pot Identification of BCR/ABLp210 Transcript Isoforms Based on Nanocluster Beacon.

The BCR/ABLp210 fusion gene is a classic biomarker of chronic myeloid leukemia, which can be divided into e13a2 and e14a2 isoforms according to different breakpoints. These two isoforms showed distinct differences in clinical manifestation, treatment effect, and prognosis risk. Herein, a strategy based on nanocluster beacon (NCB) fluorescence was developed to identify the e13a2 and e14a2 isoforms in one-pot. Because the fluorescence of AgNCs can be activated when they are placed in proximity to the corresponding enhancer sequences, thymine-rich (T-rich) or guanine-rich (G-rich). In this work, we explored an ideal DNA-AgNCs template as an excellent molecular reporter with a high signal-to-noise ratio. After recognition with the corresponding isoforms, the AgNCs can be pulled closer to the T-rich or G-rich sequences to form a three-way junction structure and generate fluorescence with corresponding wavelengths. Therefore, by distinguishing the corresponding wavelengths of AgNCs, we successfully identified two isoforms in one tube with the limitation of 16 pM for e13a2 and 9 pM for e14a2. Moreover, this strategy also realized isoform identification in leukemia cells and newly diagnosed CML patients within 40 min, which provides a powerful tool to distinguish fusion gene subtypes at the same time.

Light up multiple protein dimers on cell surface based on proximity-induced fluorescence activation of DNA-templated sliver nanoclusters.

Efficient and multiple analysis of receptor protein dimers is highly necessary, due to their important role in the occurrence and development of cancer. Herein, we report a turn-on strategy to visualize human epidermal growth factor receptor (HER) dimers on cell surfaces. By taking advantages of specific aptamer recognition and proximity-induced fluorescence activation of DNA-templated sliver nanoclusters (DNA/AgNCs) by guanine (G)-rich sequence, we attached the two kind of DNA/AgNCs sequence with different fluorescence properties to the corresponding HER aptamer to form aptamer-functionalized AgNCs probes, and attached G-rich sequence to the corresponding HER aptamer as enhancer. In the presence of protein dimers, after aptamer specific recognition and binding, it will draw the dark AgNCs probes close to the G-rich probes and then excite corresponding fluorescence. As a result, this approach has successfully realized imaging of HER2:HER2 homodimer and HER2:HER3 heterodimer at the same time, which was provided a new idea for the simultaneous detection of multiple HER2 dimers in situ. This AgNCs-based light up strategy provides a potential tool for further investigation of protein dimerization on cell surface, which is more conducive to the mechanism research, accurate classification and treatment of cancer.

MiR-622 functions as a tumor suppressor and directly targets E2F1 in human esophageal squamous cell carcinoma.

PURPOSE: MicroRNA-622 has been proven down-regulated in many human malignancies and correlated with tumor progression. However, its role in esophageal squamous cell carcinoma (ESCC) is still unclear. The aim of this study was to explore the expression and function of miR-622 in ESCC. METHODS: Using quantitative RT-PCR, we detected miR-622 expression in ESCC cell lines and primary tumor tissues. The association of miR-622 expression with clinicopathological factors and prognosis was also analyzed. Then, the effects of miR-622 on the biological behavior of ESCC cells were investigated. At last, the potential regulatory function of miR-622 on E2F1 expression was confirmed. RESULTS: miR-622 was found to be down-regulated in ESCC tissues and cell lines. Decreased miR-622 expression was closely correlated with aggressive clinicopathological features and poor overall survival. Multivariate regression analysis corroborated that low level of miR-622 expression was an independent unfavourable prognostic factor for patients with ESCC. Up-regulation of miR-622 could significantly reduce ESCC cell proliferation, enhance cell apoptosis, and impair cell invasion and migration in vitro, while down-regulation of miR-622 showed opposite effects. Further, E2F1 was confirmed as a direct target of miR-622 by using Luciferase Reporter Assay. CONCLUSIONS: These findings indicate that miR-622 may act as a tumor suppressor in ESCC and would serve as a potential therapy target for this disease.

Increased insulin-like growth factor 1 receptor (IGF1R) expression in small cell lung cancer and the effect of inhibition of IGF1R expression by RNAi on growth of human small cell lung cancer NCI-H446 cell.

Insulin-like growth factor 1 receptor (IGF1R) is a tyrosine kinase receptor implicated in tumourigenesis that may be an attractive target for anti-cancer treatment. In this study, the expression and clinical significance of IGF1R were investigated in serum and lung cancer tissues from small cell lung cancinoma (SCLC). We also compared the effect of IGF1R up-regulation and IGF1R inhibition on viability and apoptosis of NCI-H446 cells. We found the concentration of IGF1R in blood serum was significantly increased and positive IGF1R protein in cancer tissue was more prevalent in SCLC. A statistically significant correlation among IGF1R-positve tumors, lymph node metastasis and local invasion was discussed. Furthermore, IGF1R overexpression lead to an increase of cell survival and suppressed cell apoptosis, IGF1R silencing mediated by RNAi abrogate this response of NCI-H446 cells. Our results further demonstrated that the effects of these treatments may be assigned to the effective inhibition of lung cancer cells from Akt/P27(Kip1) pathway in IGF-1R signaling. These features may have important implications for future anti-IGF1R therapeutic approaches.

Expression and clinical significance of IGF-1, IGFBP-3, and IGFBP-7 in serum and lung cancer tissues from patients with non-small cell lung cancer.

The expression and clinical significance of insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), and insulin-like growth factor binding protein 7 (IGFBP-7) were investigated in serum and lung cancer tissues from 57 patients with non-small cell lung cancer (NSCLC). Lung cancer tissues at different pathologic stages (27 patients at stages I-II and 30 patients at stages III-IV), normal lung tissues from 17 patients with benign pulmonary disease, and serum samples from both lung cancer and benign pulmonary disease patients were collected during surgery. Enzyme-linked immunosorbent assay and avidin-biotin-peroxidase complex immunohistochemical staining were used to detect IGF-1, IGFBP-3, and IGFBP-7 expression in serum and tissues, respectively. The results show that expression of IGF-1 in lung cancer tissues and serum from NSCLC patients were significantly higher than in the control (P < 0.05). However, expression of IGFBP-3 and IGFBP-7 in cancer tissues and serum from NSCLC patients was significantly lower than in the control (P < 0.05). These results suggest that upregulation of IGF-1 and downregulation of IGFBP-3 and IGFBP-7 may be potential diagnostic biomarkers for NSCLC.