Microfluidic-SERS sensing system based on dual signal amplification and aptamer for gastric cancer detection.

Studies have found that matrix metalloproteinase-9 (MMP-9) and interleukin-6 (IL-6) play an important role in tumorigenesis. In order to detect MMP-9 and IL-6 concentrations with high sensitivity and specificity, an efficient microfluidic-SERS sensing system was prepared based on surface-enhanced Raman scattering (SERS). The aptamer recognition-release mechanism and the dual signal amplification strategy were applied in the sensing system. The sensor system was developed using two kinds of nanomaterials with excellent SERS properties, namely gold-coated iron tetroxide particles (Fe3O4@AuNPs) and gold nanocages (AuNCs). In addition, Fe3O4@AuNPs also has magnetic adsorption properties. In the sensing system, single-stranded DNA1 (ssDNA1) and aptamer were modified on Fe3O4@AuNPs. Single-stranded DNA2 (ssDNA2) and Raman tags were modified on AuNCs. When the target was present, the aptamer bound to the target and detached from the Fe3O4@AuNPs, and ssDNA2 bound to the exposed ssDNA1. At this time, the Fe3O4@AuNPs@AuNCs@SERS tag complex was formed, and the SERS signal was enhanced for the first time. Under the action of an external magnet on the microfluidic chip, the complex was magnetized and enriched. The SERS signal was enhanced for the second time. Due to the high affinity between the aptamer and the target object, the sensing system has a strong specificity. The double amplification of the SERS signal gave the system excellent sensitivity. The limit of detection (LOD) relative to MMP-9 and IL-6 were as low as 0.178 pg/mL and 0.165 pg/mL, respectively. The microfluidic-SERS sensing system has a feasible prospect in the early screening of gastric cancer.

A polyaniline functionalized NiFeP nanosheet array-based electrochemical immunosensor using Au/Cu2O nanocubes as a signal amplifier for the detection of SARS-CoV-2 nucleocapsid protein.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which emerged as a novel pathogen in 2019. The virus is responsible for a severe acute respiratory syndrome outbreak, affecting the respiratory system of infected individuals. COVID-19 is a super amplifier of basic diseases, and the disease with basic diseases is often more serious. Controlling the spread of the COVID-19 pandemic relies heavily on the timely and accurate detection of the virus. To resolve the problem, a polyaniline functionalized NiFeP nanosheet array-based electrochemical immunosensor using Au/Cu2O nanocubes as a signal amplifier is fabricated for the detection of SARS-CoV-2 nucleocapsid protein (SARS-CoV-2 NP). Polyaniline (PANI) functionalized NiFeP nanosheet arrays are synthesized as an ideal sensing platform for the first time. PANI is coated on the surface of NiFeP by electropolymerization to enhance biocompatibility, beneficial for the efficient loading of the capture antibody (Ab1). Significantly, Au/Cu2O nanocubes possess excellent peroxidase-like activity and exhibit outstanding catalytic activity for the reduction of H2O2. Therefore, Au/Cu2O nanocubes combine with a labeled antibody (Ab2) through the Au-N bond to form labeled probes, which can effectively amplify current signals. Under optimal conditions, the immunosensor for the detection of SARS-CoV-2 NP shows a wide linear range of 10 fg mL-1-20 ng mL-1 and a low detection limit of 1.12 fg mL-1 (S/N = 3). It also exhibits desirable selectivity, repeatability, and stability. Meanwhile, the excellent analytical performance in human serum samples confirms the practicality of the PANI functionalized NiFeP nanosheet array-based immunosensor. The electrochemical immunosensor based on the Au/Cu2O nanocubes as a signal amplifier demonstrates great potential for application in the personalized point-of-care (POC) clinical diagnosis.

A comparative transcriptome analysis of how shrimp endure and adapt to long-term symbiosis with Enterocytozoon hepatopenaei infection.

Enterocytozoon hepatopenaei (EHP) is a prevalent microsporidian pathogen responsible for hepatopancreatic microsporidiosis (HPM) in Litopenaeus vannamei. This infection not only leads to slowed growth in shrimp abut aslo inflicts substantial economic losses in the global aquaculture industry. However, the molecular mechanisms by which EHP influences the host during various infection stages remain unclear. This study employed comparative transcriptomics to examine the effects of EHP infection on Litopenaeus vannamei between early and late stage of infection groups. Utilizing transcriptomic approaches, we identified differentially expressed genes (DEGs) with notable biological significance through the COG, GO, KEGG, GSEA, and Mufzz time-series methodologies. The results reveal that EHP infection considerably influences host gene expression, with marked differences between early and late infection across distinct timeframes. Key processes such as detoxification, cell apoptosis, and lipid metabolism are pivotal during host-parasite interactions. Hexokinase and phosphatidic acid phosphatase emerge as key factors enabling invasion and sustained effects. Cytochrome P450 and glucose-6-phosphate dehydrogenase could facilitate infection progression. EHP significantly impacts growth, especially through ecdysteroids and 17ß-estradiol dehydrogenase. By delineating stage-specific effects, we gain insights into interaction between EHP and Litopenaeus vannamei, showing how intracellular pathogens reprogram host defenses into mechanisms enabling long-term persistence. This study provides a deeper understanding of host-pathogen dynamics, emphasizing the interplay between detoxification, metabolism, immunity, apoptosis and growth regulation over the course of long-term symbiosis.

A microfluidic chip using Au@SiO2 array-based highly SERS-active substrates for ultrasensitive detection of dual cervical cancer-related biomarkers.

In this work, a microfluidic chip using Au@SiO2 array-based highly active SERS substrates was developed for quantitative detection of squamous cell carcinoma antigen (SCCA) and carcinoembryonic antigen (CEA) associated with cervical cancer. The chip consisted of six functional units with pump-free design, enabling parallel detection of multiple samples in an automatic manner without external pumps and improving the portability. Ag nanocubes (AgNCs) were labeled with Raman reporters and coupled with antibodies (labeling) to prepare SERS tags, while the Au nanoparticle-modified SiO2 microsphere (Au@SiO2) array was conjugated with antibodies (coating) to generate the highly SERS-active capturing substrate. In the presence of target biomarkers, they were captured by SERS tags and capturing substrate, resulting in the formation of "sandwich" structures which were trapped in the detection chamber. As the immune reaction proceeded, a large number of "hot spots" were generated by the proximity of the Au@SiO2 array substrate and AgNCs, greatly amplifying SERS signals. With this chip, the limits of detection of the SCCA and CEA levels in human serum were estimated to be as low as 0.45 pg mL-1 and 0.36 pg mL-1, respectively. Furthermore, the good selectivity and reproducibility of this chip were confirmed. Finally, clinical serum samples were analyzed by this chip, and the outcomes were consistent with those of enzyme-linked immunosorbent assay (ELISA). Thus, the proposed microfluidic chip can be potentially applied for the clinical diagnosis of cervical cancer.

A pump-free and high-throughput microfluidic chip for highly sensitive SERS assay of gastric cancer-related circulating tumor DNA via a cascade signal amplification strategy.

Circulating tumour DNA (ctDNA) has emerged as an ideal biomarker for the early diagnosis and prognosis of gastric cancer (GC). In this work, a pump-free, high-throughput microfluidic chip coupled with catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR) as the signal cascade amplification strategy (CHA-HCR) was developed for surface-enhanced Raman scattering (SERS) assays of PIK3CA E542K and TP53 (two GC-related ctDNAs). The chip consisted of six parallel functional units, enabling the simultaneous analysis of multiple samples. The pump-free design and hydrophilic treatment with polyethylene glycol (PEG) realized the automatic flow of reaction solutions in microchannels, eliminating the dependence on external heavy-duty pumps and significantly improving portability. In the reaction region of the chip, products generated by target-triggered CHA initiated the HCR, forming long nicked double-stranded DNA (dsDNA) on the Au nanobowl (AuNB) array surface, to which numerous SERS probes (Raman reporters and hairpin DNA-modified Cu2O octahedra) were attached. This CHA-HCR strategy generated numerous active "hot spots" around the Cu2O octahedra and AuNB surface, significantly enhancing the SERS signal intensity. Using this chip, an ultralow limit of detection (LOD) for PIK3CA E542K (1.26 aM) and TP53 (2.04 aM) was achieved, and the whole process was completed within 13 min. Finally, a tumour-bearing mouse model was established, and ctDNA levels in mouse serum at different stages were determined. To verify the experimental accuracy, the gold-standard qRT-PCR assay was utilized, and the results showed a high degree of consistency. Thus, this rapid, sensitive and cost-effective SERS microfluidic chip has potential as an ideal detection platform for ctDNA monitoring.

PSD-93 mediates the crosstalk between neuron and microglia and facilitates acute ischemic stroke injury by binding to CX3CL1.

Post-synaptic density 93 (PSD-93) mediates glutamate excitotoxicity induced by ischemic brain injury, which then induces microglial inflammatory response. However, the underlying mechanisms of how PSD-93 mediates the crosstalk between neurons and microglia in the post-synaptic dense region remain elusive. CX3 chemokine ligand 1 (CX3CL1) is a chemokine specifically expressed in neurons while its receptor CX3CR1 is highly expressed in microglia. In this study, we examined the interaction of PSD-93 and CX3CL1 in the crosstalk between neurons and microglia in acute ischemic stroke. We utilized male C57BL/6 mice to establish the middle cerebral artery occlusion model (MCAO) and designed a fusion small peptide Tat-CX3CL1 (357-395aa) to inhibit PSD-93 and CX3CL1 interaction. The combination peaks of PSD-93 and CX3CL1 at 6 hr after I/R were observed. The binding sites were located at the 420-535 amino acid sequence of PSD-93 and 357-395 amino acid sequence of CX3CL1. Tat-CX3CL1 (357-395aa) could inhibit the interaction of PSD-93 and CX3CL1 and inhibited the pro-inflammatory cytokine IL-1ß and TNF-α expression and provided neuroprotection following reperfusion. Together, these data suggest that PSD-93 binds CX3CL1 to activate microglia and initiate neuroinflammation. Specific blockade of PSD-93-CX3CL1 interaction reduces I/R induced neuronal cell death, and provides a new therapeutic target for ischemic stroke.

A three-dimensional CoNi-MOF nanosheet array-based immunosensor for sensitive monitoring of human chorionic gonadotropin with core-shell ZnNi-MOF@Nile Blue nanotags.

A CoNi-based metal-organic framework (CoNi-MOF) nanosheet array is synthesized by the treatment of a CoNi layered double hydroxide nanosheet array on Ni foam with 3,5-diaminobenzoic acid. The CoNi-MOF nanosheet array with amino and carboxyl groups can be used to capture the human chorionic gonadotropin (HCG) primary antibody (HCG Ab1). Nile Blue decorated ZnNi-MOF (NB@ZnNi-MOF) spheres immobilized with HCG secondary antibodies (HCG Ab2) are used for signal amplification. When HCG exists in an analytical sample, a sandwich structure is formed and an electrochemical signal is produced. The analytical signal generated during the detection is caused by the conversion of Co(ii) and Co(iii) in the CoNi-MOF nanosheet array. The Nile Blue of the NB@ZnNi-MOF sphere, as a kind of redox-active species, is responsible for the electrochemical signal amplification in the immunosensor. On the basis of the above advantages, the HCG immunosensor exhibits a lower limit of detection (1.85 × 10-3 mIU mL-1) and a wide linear range from 0.005 mIU mL-1 to 250 mIU mL-1. Additionally, this immunosensor is used to quantitatively detect HCG in human blood serum and shows good correlations with the standard enzyme-linked immunosorbent assay (ELISA), providing a high value on clinical diagnosis.

A novel DNA biosensor for the ultrasensitive detection of DNA methyltransferase activity based on a high-density "hot spot" SERS substrate and rolling circle amplification strategy.

Herein, we proposed a novel biosensor based on a high-density "hot spot" Au@SiO2 array substrate and rolling circle amplification (RCA) strategy for the ultrasensitive detection of CpG methyltransferase (M.SssI) activity. In the presence of M.SssI, the RCA process can be triggered, causing the augmentation of the single-stranded DNA (ssDNA) at the tail of the double-stranded DNA (dsDNA), and the ssDNA can be hybridized with numerous DNA probes labeled with Raman reporters in the next steps. Afterwards, the resultant ssDNA can be modified to the Au@SiO2 array substrate with the SERS enhancement factor of 7.49 × 106. The substrate was synthesized by using a monolayer SiO2 array to pick up the Au nanoparticle (AuNP) array and finite-difference time-domain (FDTD) simulation showed its excellent SERS effect. Particularly, the developed biosensor displayed a significant sensitivity with a broad detection range covering from 0.005 to 50 U mL-1, and the limits of detection (LODs) in PBS buffer and human serum were 2.37 × 10-4 U mL-1 and 2.51 × 10-4 U mL-1, respectively. Finally, in order to verify the feasibility of its clinical application, the serum samples of healthy subjects and breast cancer, prostate cancer, gastric cancer and cervical cancer patients were analyzed, and the reliability of the results was also confirmed by western blot (WB) experiments. Taking advantage of these merits, the proposed biosensor can be a very promising alternative tool for the detection of M.SssI activity, which is of vital importance in the early detection and prevention of tumors.

A SERS-LFA biosensor combined with aptamer recognition for simultaneous detection of thrombin and PDGF-BB in prostate cancer plasma.

An innovative surface-enhanced Raman spectroscopy and lateral flow assay (SERS-LFA) biosensor combined with aptamer recognition had been developed for the convenient, rapid, sensitive and accurate detection of thrombin and platelet-derived growth factor-BB (PDGF-BB) associated with prostate cancer simultaneously. During the biosensor operation, thrombin and PDGF-BB in the sample were recognized and combined by thiol-modified aptamers immobilized on Au-Ag hollow nanoparticles (Au-Ag HNPs) surface and biotinylated aptamers immobilized on the test lines of the biosensor. Thus, thrombin and PDGF-BB were simultaneously captured between detection aptamers and capture aptamers in a sandwich structure. Finite difference time domain simulation confirmed that 'hot spots' appeared at the gaps of Au-Ag HNPs dimer in the enhanced electromagnetic field compared to that of a single Au-Ag HNP, indicating that the aggregated Au-Ag HNPs owned a good SERS signal amplification effect. The detection limits of thrombin and PDGF-BB in human plasma were as low as 4.837 pg ml-1and 3.802 pg ml-1, respectively. Moreover, the accuracy of the biosensor which was applied to detect thrombin and PDGF-BB in prostate cancer plasma had been verified. This designed biosensor had broad application prospects in the clinical diagnosis of prostate cancer.

SERS spectroscopy using Au-Ag nanoshuttles and hydrophobic paper-based Au nanoflower substrate for simultaneous detection of dual cervical cancer-associated serum biomarkers.

Ultrasensitive detection of specific biomarkers in clinical serum is helpful for early diagnosis of cervical cancer. In this paper, a surface-enhanced Raman scattering (SERS)-based immunoassay was developed for the simultaneous determination of squamous cell carcinoma antigen (SCCA) and osteopontin (OPN) in cervical cancer serum. Au-Ag nanoshuttles (Au-AgNSs) as SERS tags and hydrophobic filter paper-based Au nanoflowers (AuNFs) as capture substrate were constructed into a sandwich structure which served as an ultrasensitive SERS-based immunoassay platform. Finite difference time domain simulation confirmed that the electromagnetic field coupled between the AuNFs had a prominent SERS signal enhancement effect, which improved the detection sensitivity. SERS mapping showed that hexadecenyl succinic anhydride hydrophobic treatment could prevent the analyte from being quickly absorbed by the filter paper and increase the retention time to be more evenly distributed on the filter paper substrate. The immunoassay platform was verified to have good selectivity and reproducibility. With this method, the detection limits of SCCA and OPN in human serum were as low as 8.628 pg/mL and 4.388 pg/mL, respectively. Finally, in order to verify the feasibility of its clinical application, the serum samples of healthy subjects; cervical intraepithelial neoplasia I (CINI), CINII, and CINIII; and cervical cancer patients were analyzed, and the reliability of the results was confirmed by enzyme-linked immunosorbent assay experiments. The constructed SERS-based immunoassay platform could be used as a clinical tool for early screening of cancers in the future.

Fine particulate matter increases airway hyperresponsiveness through kallikrein-bradykinin pathway.

Epidemiological studies have reported short-term fine particulate matter (PM2.5) exposure to increase incidence of asthma, related to the increase of airway hyperresponsiveness (AHR); however, the underlying mechanism remains unclear. Aim of this study was to elucidate the role of kallikrein in PM2.5-induced airway hyperresponsiveness and understand the underlying mechanism. Nose-only PM2.5 exposure system was used to generate a mouse model of airway hyperresponsiveness. Compared with the control group, PM2.5 exposure could significantly increase airway resistance, lung inflammation, kallikrein expression of bronchi-lung tissue and bradykinin (BK) secretion. However, these changes could be alleviated by kallikrein inhibitor. In addition，PM2.5 could increase the viability of human airway smooth muscle cells (hASMCs), accompanied by increased expression of kallikrein 14 (Klk14), bradykinin 2 receptor (B2R), bradykinin secretion and cytosol calcium level, while kallikrein 14 gene knockdown could significantly amelioratethe above response induced by PM2.5. Taken together, the data suggested kallikrein to play a key role in PM2.5-induced airway hyperresponsiveness, and that it could be a potential therapeutic target in asthma.

Factors Associated with Pre-Hospital Delay and Intravenous Thrombolysis in China.

BACKGROUND: Pre-hospital delay was a critical factor affecting stroke patients receiving intravenous thrombolytic therapy. The aim of this study was to explore the factors associated with pre-hospital delay and thrombolysis in China. METHODS: Patient data were obtained from emergency department (ED), and the factors of patient pre-hospital delay were recorded through a well-designed form. RESULTS: A total of 630 patients were eventually included in the study. 317 patients were admitted to the ED during the thrombolysis time window, and only 105 patients received intravenous thrombolytic therapy. In the univariate analysis, transportation (OR: 0.15; 95% CI: 0.44 - 0.518; p = 0.001), atrial fibrillation (OR: 0.555; 95% CI: 0.372-0.828; p = 0.004) and response of symptoms (OR: 0.002; 95% CI: 0.000-0.013; p = 0.000) were associated with early arrival. Speech disturbances (OR: 2.095; 95% CI: 1.294-3.391; p = 0.002), smoking (OR: 2.563; 95% CI: 1.527-4.304; p = 0.000), alcohol consumption (OR: 2.155; 95% CI: 1.159-4.005; p = 0.014) and referral presentation (OR: 2.837; 95% CI: 1.584-5.082; p = 0.000) were associated with thrombolysis. In the logistic regression analysis, direct visiting to the hospital after onset and rushing to emergency after onset were independent predictor of early arrival of AIS and intravenous thrombolytic. CONCLUSIONS: The pre-hospital delay of acute ischemic stroke in China was still serious. Strengthening the ability to identify stroke-related symptoms and establishing a mutual referral medical support service model between lower and upper hospitals may effectively shorten the pre-hospital delay of stroke patients.

Quantitative and specific detection of cancer-related microRNAs in living cells using surface-enhanced Raman scattering imaging based on hairpin DNA-functionalized gold nanocages.

Variations in the intracellular expression level of cancer-related microRNAs (miRNAs) are connected with worsening tumor progression. A simple, accurate, and sensitive analytical method for the imaging and detection of intracellular miRNA is still a great challenge due to the low abundance of miRNAs and the complexity of intracellular environments. In this work, target miRNA (miRNA)-mediated catalytic hairpin assembly (CHA)-induced gold nanocage (GNC)-hairpin DNA1 (hpDNA1)-hpDNA2-GNC nanostructures were designed for surface-enhanced Raman scattering (SERS) detection and imaging of the specific miR-125a-5p in the normal lung epithelial cell line (BEAS-2B cells) and lung cancer cell line (A549 cells). The finite difference time domain (FDTD) simulations showed that the polymer of GNCs possessed a much stronger electromagnetic field in nanogaps than that of single GNC, theoretically confirming the rational design of the CHA assembly strategy. Using this method, miR-125a-5p can be detected in a wide linear range with a detection limit of 43.96 aM and high selectivity over other miRNAs in vitro. Moreover, SERS imaging successfully detected and distinguished the expression levels of intracellular miR-125a-5p in BEAS-2B cells and A549 cells. The results obtained by the SERS assay were consistent with those obtained by the real-time quantitative polymerase chain reaction (qRT-PCR). This method can offer a powerful strategy for the imaging and quantitative detection of various types of biomolecules in vitro as well as in living cells.

Copper(II) 1,4-naphthalenedicarboxylate on copper foam nanowire arrays for electrochemical immunosensing of the prostate specific antigen.

Nanowires of copper(II)-based metal-organic frameworks (Cu-MOFs) of type Cu(II)(1,4-naphthalenedicarboxylic acid) (1,4-NDC) were deposited on the surface of a copper foam by immersion of Cu(OH)2 nanowires in a solution of 1,4-NDC. An electrochemical immunosensor for the prostate specific antigen (PSA) is obtained by using the nanowire arrays as a redox signal probe. The signal is generated by the conversion of Cu(I) and Cu(II) of Cu-MOFs nanowires. Cu(1,4-NDC) nanowires contain many uncoordinated carboxyl groups which can bind to the amino groups of the PSA antibody. When PSA antibody binds to PSA antigen during an immune response, the current signal will decrease due to the electrical insulation of PSA antigen. The decrease of current is directly proportional to the increase of PSA concentration. The immunosensor, best operated at a voltage of typically -0.08 V (vs. Ag/AgCl), has a low limit of detection (4.4 fg·mL-1) and a wide linear range (0.1 pg·mL-1 to 20 ng·mL-1). This meets the demands of clinical diagnosis (with values <4 ng·mL-1) in serum. The method was applied to the determination of PSA in spiked serum. Graphical abstractSchematic representation of the in-situ growth of ordered Cu-MOFs wrapped with Cu(OH)2 nanowires, building the core-shell structure as the 3D electrode. A novel electrochemical immunosensor for PSA detection has been exploited, using the Cu-MOFs nanowire arrays on Cu foam as a redox signal probe for the first time.

IKULDAS: An Improved kNN-Based UHF RFID Indoor Localization Algorithm for Directional Radiation Scenario.

Ultra high frequency radio frequency identification (UHF RFID)-based indoor localization technology has been a competitive candidate for context-awareness services. Previous works mainly utilize a simplified Friis transmission equation for simulating/rectifying received signal strength indicator (RSSI) values, in which the directional radiation of tag antenna and reader antenna was not fully considered, leading to unfavorable performance degradation. Moreover, a k-nearest neighbor (kNN) algorithm is widely used in existing systems, whereas the selection of an appropriate k value remains a critical issue. To solve such problems, this paper presents an improved kNN-based indoor localization algorithm for a directional radiation scenario, IKULDAS. Based on the gain features of dipole antenna and patch antenna, a novel RSSI estimation model is first established. By introducing the inclination angle and rotation angle to characterize the antenna postures, the gains of tag antenna and reader antenna referring to direct path and reflection paths are re-expressed. Then, three strategies are proposed and embedded into typical kNN for improving the localization performance. In IKULDAS, the optimal single fixed rotation angle is introduced for filtering a superior measurement and an NJW-based algorithm is advised for extracting nearest-neighbor reference tags. Furthermore, a dynamic mapping mechanism is proposed to accelerate the tracking process. Simulation results show that IKULDAS achieves a higher positioning accuracy and lower time consumption compared to other typical algorithms.

A Series of Lanthanide-Based Metal-Organic Frameworks: Synthesis, Structures, and Multicolor Tuning of Single Component.

The single component (SC) white-light emitting (WLE) metal-organic frameworks based on europium (Eu-MOFs), which could be applied in lighting and display, have drawn great attention but have rarely been exploited. In this work, we dedicated to design and synthesize SC-WLE Eu-MOFs via a dichromatic strategy on the balance of simultaneous ligand-based and Eu-based emissions. The Eu-MOF {[Eu4(obb)6(H2O)9]·(H2O)}∞ (IAM16-3) generated via the self-assembly of the flexible ligand 4,4'-oxybisbenzoic acid (H2obb) and europium ions displays fascinating excitation-wavelength-dependent photoluminescence (EWDP) property. Upon different excitation wavelengths, tunable WLE through manipulating the intensity ratio of characteristic emissions of Eu3+ ions and ligand-based emissions was performed. To the best of our knowledge, this is the first example for Eu-MOFs to yield SC-WLE stemming from EWDP property. Three isomorphic lanthanide-based MOFs (LnMOFs), that is, {[Ln4(obb)6(H2O)9]·(H2O)}∞ (Eu3+: IAM16-3; Tb3+: IAM16-4; Dy3+: IAM16-5) based on the flexible bridging linker, that is, 4,4'-oxybisbenzoic acid (H2obb), were obtained. The Eu-MOF, showing with EWDP property, is the first example of SC WLE Eu-MOFs via a dichromatic strategy on the balance of the simultaneous ligand-based and Eu(III)-based emissions at different excitation wavelengths.

Two Silver Coordination Network Compounds with Colorful Photoluminescence.

The excitation-wavelength-dependent photoluminescence (EWDP) property of flexible organic ligand 1,4-bis(2-methyl-imidazol-1-yl)butane (Bmib) was observed. Herein, Bmib was chosen as a bridge linker to react with AgX (X = Br and I) to synthesize novel coordination network compounds (CNCs) with interesting EWDP properties. As anticipated, under the same hydrothermal synthesis conditions, two new isomorphic CNCs, i.e. [Ag2(Bmib)Br2]∞ (IAM16-1) and [Ag2(Bmib)I2]∞ (IAM16-2), as the first examples of CNCs showing EWDP properties, have been obtained. The EWDP properties may be attributed to the stretch and rotation of the long -(CH2)4- chains of Bmib and the spatial orientation adjustment of the methyl group of each imidazole ring at different excitation wavelengths. It is a great challenge to point out the emission mechanisms of CNCs merely from the experimental results due to their multiple charge transfer routes. To address this issue, we adopt DFT calculations to pursue in-depth investigation of the emission mechanisms for IAM16-1 and IAM16-2, respectively.

Synthesis of Au Nanostars and Their Application as Surface Enhanced Raman Scattering-Activity Tags Inside Living Cells.

This work presents the synthesis and characterization of Au nanostars (AuNSs) and demonstrates their application as surface enhanced Raman scattering (SERS)-activity tags for cellular imaging and sensing. Nile blue A (NBA) and bovine serum albumin (BSA) were used as Raman reporter molecules and capping materials, respectively. The SERS-activity tags were tested on human lung adenocarcinoma cell (A549) and alveolar type II cell (AT II) and found to present a low level of cytotoxicity and high chemical stability. These SERS-activity tags not only can be applied in multiplexed cellular imaging, including dark field imaging, transmission electron microscopy (TEM) and SERS imaging, but also can be used for cellular sensing. The SERS spectra clearly identified cellular important components such as proteins, nucleic acids, lipids, and carbohydrates. This study also shows that endocytosis is the main channel of tags internalized in cells. The AuNSs exhibiting strong surface enhanced Raman effects are utilized in the design of an efficient, stable SERS-activity tag for intracellular applications.

RBAP, a rhodamine B-based derivative: synthesis, crystal structure analysis, molecular simulation, and its application as a selective fluorescent chemical sensor for Sn2+.

A new fluorescent chemosensor based on a Rhodamine B and a benzyl 3-aminopropanoate conjugate (RBAP) was designed, synthesized, and structurally characterized. Its single crystal structure was obtained and analyzed by X-ray analysis. In a MeOH/H2O (2:3, v/v, pH 5.95) solution RBAP exhibits a high selectivity and excellent sensitivity for Sn2+ ions in the presence of many other metal cations. The binding analysis using the Job's plot suggested the RBAP formed a 1:1 complex with Sn2+.

SERS Analysis Platform Based on Aptamer Recognition-Release Strategy for Efficient and Sensitive Diagnosis of Colorectal Precancerous Lesions.

Background: Colorectal cancer (CRC) has become a significant global public health challenge, demanding immediate attention due to its high incidence and mortality rates. Regular CRC screening is essential for the early detection of precancerous lesions and CRC. Methods: : We developed a novel surface-enhanced Raman scattering (SERS) analysis platform that employs high-throughput microarray chips as carriers and Au/SnO2 nanoring arrays (Au/SnO2 NRAs) as substrates. This platform utilizes an aptamer recognition-release strategy to achieve efficient and sensitive detection of protein tumor markers. In the detection process, the strong affinity and high specificity between the aptamer and the target protein result in competitive replacement of the SERS nanoprobes originally bound to the substrate surface. As a result, the SERS nanoprobes carrying Raman reporter genes are dislodged, leading to a reduction in the SERS signal intensity. Results: The platform demonstrated excellent detection performance, with rapid detection completed within 15 minutes and limits of detection (LOD) as low as 6.2×10-12 g/mL for hnRNP A1 and 6.51×10-12 g/mL for S100P. Clinical samples analyzed using the SERS platform showed high consistency with enzyme-linked immunosorbent assay (ELISA) results. Conclusion: This platform offers strong support for the early detection, risk assessment, and treatment monitoring of colorectal cancer precancerous lesions, with broad potential for clinical applications.