Hybrid molecular probe for nucleic acid analysis in biological samples

The ability to detect changes in gene expression, especially in real-time and with sensitivity sufficient enough to monitor small variations in a single-cell, will have considerable value in biomedical research and applications. Out of the many available molecular probes for intracellular monitoring of nucleic acids, molecular beacon (MB) is the most frequently used probe with the advantages of high sensitivity and selectivity. However, any processes in which the MB stem-loop structure is broken will result in a restoration of the fluorescence in MB. This brings in a few possibilities for false positive signal such as nuclease degradation, protein binding, thermodynamic fluctuation, solution composition variations (such as pH, salt concentration) and sticky-end pairing. These unwanted processes do exist inside living cells, making nucleic acid monitoring inside living cells difficult. We have designed and synthesized a hybrid molecular probe (HMP) for intracellular nucleic acid monitoring to overcome these problems. HMP has two DNA probes, one labeled with a donor and the other an acceptor. The two DNA probes are linked by a poly(ethylene glycol) (PEG) linker, with each DNA being complementary to adjacent areas of a target sequence. Target binding event brings the donor and acceptor in proximity, resulting in quenching of the donor fluorescence and enhancement of the acceptor emission. The newly designed HMP has high sensitivity, selectivity, and fast hybridization kinetics. The probe is easy to design and synthesize. HMP does not generate any false positive signal upon digestion by nuclease, binding by proteins, forming complexes by sticky-end pairing, or by other molecular interaction processes. HMP is capable of selectively detecting nucleic acid targets from cellular samples.     

一类含参数的分块对称矩阵的正定性及应用

首先给出一种判断分块对称矩阵正定的方法,提供了确定一组尽可能小的参数,使一类含参数的分块对称矩阵正定的简单算法,然后,将其结果用于研究线性定常大系统的分散镇定性,得到了一类可分散镇定的线性大系统,并给出了相应的分散镇定算法,同文献中提供的方法相比,该算法不仅扩大了所考虑的系统范围,而且不会引起过高的反馈增益,同时还简单易算。     

(Eu2+,Nd3+)∶CaAl2O4的长余辉发光及机理的研究

采用高温固相反应法制备了Eu^2 ∶CaAl2O4、（Eu^2 ,Nd^3 )∶CaAl2O4，等系列材料。测量了其激发、发射光谱及余辉衰减曲线。分析了掺杂稀土离子对长余辉发光的作用。并对其发光机理进行了深入地探讨。     

碳18键合硅胶柱-流动注射-电感耦合等离子体质谱联用技术及其在海水分析中的应用

建立了碳18键合硅胶柱-流动注射-电感耦合等离子体质谱(C18-FI-ICP/MS)联用系统。对螯合反应的pH,碳18柱的尺寸和填充松紧度,洗脱液中甲醇含量及洗脱液流速等进行了优化选择。联用系统已成功地应用于实际样品的在线富集分离分析。对Cd、 Pb、 Co、 Ni和Zn 5种元素的检测限(3σ)分别为0.03、0.09、0.1、0.1、0.3 μg/L, 6次测定海水的RSD分别为6.8%、3.4%、1.3%、2.6%、0.5%,标准加入方法的回收率分别为91.3%、95.1%、100.4%、100.3%、95.2%。     

Portable detection of serum HER-2 in breast cancer by a pressure-based platform

Analytical and Bioanalytical Chemistry - A high serum HER-2 extracellular domain (sHER-2 ECD) level has a reverse association with tumor behaviors. In this study, a portable platform for the...     

Target-responsive DNAzyme hydrogel for portable colorimetric detection of lanthanide(III) ions

Lanthanide elements (Ln) play an important role in industry and agriculture. As a result of the increasing consumption of lanthanides, environmental emission of Ln has become detrimental to the health of flora and fauna. Current methods for trace lanthanides detection mainly rely on sophisticated instruments. In this article, a Ln³⁺ dependent DNAzyme was incorporated into a hydrogel to generate Ln³⁺ sensitive DNAzyme hydrogel for portable colorimetric detection. The enzyme strand and its substrate strand act as crosslinker and functional unit of the hydrogel with polyacrylamide chains as the scaffold and gold nanoparticles (AuNPs) as the indicator of hydrogel stability. Any ions in the Ln³⁺ series can trigger the cleavage of substrate strand by activating the enzyme strand, thereby decreasing the crosslink ratio and leading to collapse of the hydrogel. The release of the encapsulated AuNPs turns the supernatant wine red. Using this colorimetric method, Ln³⁺ can be detected with high sensitivity, with a limit of detection (LOD) of 20 nM for Ce³⁺. The hydrogel responds specifically to any Ln³⁺ ion and works well with the spiked lake sample without the need of instruments and skilled operators. Our results suggest that the lanthanide responsive hydrogel can be used for portable and sensitive detection of Ln³⁺ contamination in the field.     

Homogeneous,Low‐volume,Efficient, and Sensitive Quantitation of Circulating Exosomal PD‐L1 for Cancer Diagnosis and Immunotherapy Response Prediction

Immunotherapy has revolutionized cancer treatment, but its efficacy is severely hindered by the lack of effective predictors. Herein, we developed a homogeneous, low‐volume, efficient, and sensitive exosomal programmed death‐ligand 1 (PD‐L1, a type of transmembrane protein) quantitation method for cancer diagnosis and immunotherapy response prediction (HOLMES‐Exo_PD‐L1). The method combines a newly evolved aptamer that efficiently binds to PD‐L1 with less hindrance by antigen glycosylation than antibody, and homogeneous thermophoresis with a rapid binding kinetic. As a result, HOLMES‐Exo_PD‐L1 is higher in sensitivity, more rapid in reaction time, and easier to operate than existing enzyme‐linked immunosorbent assay (ELISA)‐based methods. As a consequence of an outstanding improvement of sensitivity, the level of circulating exosomal PD‐L1 detected by HOLMES‐Exo_PD‐L1 can effectively distinguish cancer patients from healthy volunteers, and for the first time was found to correlate positively with the metastasis of adenocarcinoma. Overall, HOLMES‐Exo_PD‐L1 brings a fresh approach to exosomal PD‐L1 quantitation, offering unprecedented potential for early cancer diagnosis and immunotherapy response prediction.