CTAB-Co-MOFs@AuPt NPs as signal probes for the electrochemical detection of carcinoembryonic antigen 15-3.

A sensitive electrochemical strategy for carcinoembryonic antigen 15-3 (CA15-3) detection is reported using CTAB-Co-MOFs@AuPt NPs as signal probes. The electrochemical strategy was designed as follows: First, the graphene aerogel@gold nanoparticles (GA@Au NPs) nanocomposites were employed to modify the sensing surface for promoting electron transfer rate and primary antibody (Ab1) immobilization due to GA possesses a large specific surface area, eminent conductivity, and a 3D network structure. Cobalt metal-organic frameworks (CTAB-Co-MOFs) synthesized were then used as a carrier for AuPt NPs and secondary antibody (Ab2) immobilization (notes: labelled-Ab2). With sandwich immunoreaction, the labelled-Ab2 was captured on the surface of the GA@Au NPs nanocomposites. Finally, differential pulse voltammetry (DPV) was employed to register the electrochemical signal of the immunosensor at the potential of - 0.85 V (vs SCE) in phosphate buffer saline (PBS) containing 2.5 mM H2O2. It was verified that the electrochemical reduction signal from Co3+ to Co2+ was recorded. The AuPt NPs could catalyze the reaction of H2O2 oxidizing Co2+ to Co3+, resulting in the amplification of the electrochemical signal. Under the selected conditions, the immunosensor can detect CA15-3 in the range 10 µU/mL to 250 U/mL with a low detection limit of 1.1 µU/mL. In the designed strategy, the CTAB-Co-MOFs were not only employed as carriers for AuPt NPs, but also acted as signal probes. The CTAB-Co-MOFs were investigated including SEM, TEM, XPS, and XRD. The application ability of the immunosensor was evaluated using serum sample, demonstrating the immunosensor can be applied to clinic serum analysis.

Selected ssDNA aptamers-graphene oxide-based fluorescent biosensor to detect sulfameter in milk.

The abuse of sulfameter (SME) in animal husbandry can cause drug resistance and toxic or allergic reactions in humans. Therefore, it is very important to establish a simple, inexpensive, and efficient method for detecting SME in food. In this work, we propose a single fluorescent aptamer/graphene oxide (GO)-based biosensor to detect SME residues in milk. Aptamers that specifically bind to SME were screened using capture-SELEX and a ssDNA library immobilized on magnetic beads. The 68 active candidate aptamers were chemically synthesized for specificity and affinity characterization. Among the aptamers, the aptamer sulf-1 revealed the highest affinity (Kd = 77 ± 15 nM) to SME and was selected to construct a GO-based fluorescent biosensor for real milk sample detection. Under optimal conditions, the single fluorescent aptasensor had a wide linear range (R2 was 0.997) from 7 to 336 ng/ml and a low detection limit of 3.35 ng/ml that was calculated with a 3SD/slope. The single fluorescent method was also validated using SME-fortified milk samples, showing average recoveries ranging from 99.01% to 104.60% with a relative standard deviation of less than 3.88%. These results demonstrate that this novel aptamer sensor provides an opportunity for sensitive, convenient, and accurate detection of SME residues in milk.

Autonomous operation of 3D DNA walkers in living cells for microRNA imaging.

Three dimensional (3D) DNA walkers hold great potential in serving as an ideal candidate for signal transduction and amplification in bio-assays. However, the autonomous operation of 3D DNA walkers inside living cells is still few and far between, which could be attributed to the lack of suitable driving forces and moderate efficiency in terms of the cellular uptake of such complex 3D DNA components. Herein, a newly updated autonomously operated and highly integrated 3D DNA walker on Au nanoparticles (Au NPs)/zeolitic imidazolate framework-8 (ZIF-8) was activated in a tumor microenviroment and its signal amplified assay capability in living cells was demonstrated using miRNA as a sensing model biomolecule. Specifically, we assembled a 3D DNA motor, including Zn2+-dependent DNAzyme and substrates on the AuNPs grafted on ZIF-8. After being delivered into a living cell, ZIF-8 was efficiently degraded in the tumor microenvironment (low pH value), locally releasing the Zn2+ and DNA motor. Then, a self-sufficient DNA motor autonomously performed the bio-analytical task of imaging miRNA-10b, with a low detection limit of 34 pM. Also, such self-sufficient 3D walkers allowed real-time imaging of MDA-MB-231 cells by intracellular operation. This method demonstrates the self-sufficient 3D DNA motor's bioanalytical application in living cells which may inspire various other biological applications including gene delivery, therapy, etc.

Long-term survival with targeted therapy in an advanced non-small cell lung cancer patient based on genetic profiling.

Non-small cell lung cancer (NSCLC) is a profoundly devastating disease that is the leading cause of cancer-related death worldwide. With the rapid development of next-generation sequencing (NGS), which has supplied the ability to decode tumors at the DNA level, so that targeted therapy plays a crucial role in improving NSCLC survival. We first reported a 32-year-old Chinese female patient received the ninth-line treatment, who was initially diagnosed with advanced NSCLC with EGFR 19 deletion. The patient had a satisfactory clinical response to initial gefitinib treatment. Subsequently, an EGFR T790M mutation was detected from plasma-derived circulating tumor DNA (ctDNA) by ddPCR after disease progression, while NGS did not. Osimertinib was still tried but had no therapeutic effect. Then the disease even progressed on the administration of chemotherapy and gefitinib in succession. Rebiopsy for NGS detection was performed, and gefitinib plus anlotinib/vemurafenib were tried. And then, gefitinib plus crizotinib were administrated for MET amplification after the third biopsy. Furthermore, chemotherapy combined with immunotherapy was performed due to the PD-L1 positive expression. Up to now, osimertinib treatment was undertaken to base on an EGFR exon 20 T790M mutation using NGS-based genotyping in cerebrospinal fluid (CSF) ctDNA. Tumor genome dynamic monitoring can identify tumor driving genes and drug resistance mechanisms to guide tumor treatment. This study found that the total survival time of advanced NSCLC patients was more than four years after chemoradiotherapy and targeted therapy, indicating the significance of dynamic monitoring of gene alterations for cancer treatment.

PCAT1/miR-129/ABCB1 axis confers chemoresistance in non-small cell lung cancer.

Long noncoding RNA prostate cancer-associated transcript 1 (PCAT1) is oncogenic and causes progression of non-small cell lung cancer (NSCLC). We hypothesized that PCAT1 might be involved in the acquisition of chemoresistance of NSCLC cells to treatment with cisplatin (DDP). Here, we show that PCAT1 and ATP-binding cassette sub-family B member 1 (ABCB1) are highly expressed in NSCLC tissues and cell lines, and regulate the growth and apoptosis of these cells. Compared with those in DDP-sensitive patients, PCAT1 and ABCB1 are highly expressed in the tumors of DDP-resistant patients, and such overexpression correlates with a shorter overall survival of these patients. Knockdown of PCAT1 or upregulation of miR-129 led to apoptosis and sensitized the DDP-resistant cells to DDP. The 3' UTR activity of PCAT1 and ABCB1, which was increased by PCAT1 overexpression, was shown to harbor an miR-129 binding site. DDP resistance is induced by elevated ABCB1 expression, which involves binding of miR-129 in DDP resistant cells. These findings suggest that the PCAT1/miR-129/ABCB1 axis may be a potential target for the treatment of DDP-resistant oat cell cancer.

In Situ Cation Exchange Generated ZnS-Ag2S Nanoparticles for Photothermal Detection of Transcription Factor.

The photothermal reagent (PTA)-mediated point-of-care detection of disease biomarkers using thermometers as readout has attracted increasing attention, but complex modification or generation process of PTAs still limited their further applications. Herein, we report a photothermal detection platform in which the target recognition triggered the in situ generation of the PTA and ZnS-Ag2S nanoparticles (NPs) by one-step autonomous cation exchange reaction (ACER). As a proof of concept, NF-kB1, a kind of disease biomarker, was used to demonstrate the photothermal detection platform. First, a triplex-like DNA structure containing the recognition part of NF-kB1 and cytosine-Ag+-cytosine (C-Ag+-C) unit was designed. With the recognition of NF-kB1, abundant C-Ag+-C units were released to take ACER with the prepared ZnS NPs. In addition, because of the intrinsic detecting limitation of the thermometer, hybridization chain reaction (HCR) was introduced to load more Ag+ for the enhancement of the photothermal signal. After the irradiation of 808 nm laser toward the generated ZnS-Ag2S NPs dispersions, its temperature increased with the increased concentration of NF-kB1 in the range from 10 to 1000 nM with a detection limit of 2.31 nM. The signal-amplifying role of HCR was confirmed by the control experiment. This platform of in situ generation of PTA not only integrated the recognition process with detection but also avoided the complex process of modification or generation, which has remarkable potential to be extended for the detections of other different disease biomarkers.

Synthesis and catalytic properties of nickel-silica composite hollow nanospheres.

A coating process was applied to prepare nickel-silica composite hollow nanospheres (650 nm) with controllable shell thickness. The nanospheres were characterized through X-ray diffraction, transmission electron microscopy, and field emission scanning electron microscopy. This material with large BET surface area (288 m2/g) exhibits good catalytic activity and high selectivity in acetone hydrogenation reaction, showing the potential application as a catalyst in industry.