The aberrant aggregation of amyloid-β peptide (Aβ) in the brain has been considered as the major pathological hallmark of Alzheimer's diseases (AD). Inhibition of Aβ aggregation is considered as an attractive therapeutic intervention for alleviating amyloid-associated neurotoxicity. Here, we report the near-infrared light (NIR)-induced suppression of Aβ aggregation and reduction of Aβinduced cytotoxicity via porphyrinic metal-organic framework (MOF) PCN-224 nanoparticles. PCN-224 nanoparticles are hydrothermally synthesized by coordinating tetra-kis(4carboxyphenyl)porphyrin (TCPP) ligands with zirconium. The PCN-224 nanoparticles show high photo-oxygenation efficiency, good biocompatibility, and high stability. The study reveals that the porphyrinic MOF-based nanoprobe activated by NIR light could successfully inhibit self-assembly of monomeric Aβ into a β-sheet-rich structure. Furthermore, photoexcited PCN-224 nanoparticles also significantly reduce Aβ-induced cytotoxicity under NIR irradiation.

Here, a novel colorimetric sensing platform for highly selective detection of Fe 3+ in aqueous solutions was developed based on zero-dimensional Zn-MOF-74 [Zn 2 (DOBDC), DOBDC = 2,5-dihydroxyterephthalic acid] nanodots. The first ultrasmall Zn-MOF-74 nanodots with the average size within 10 nm were successfully synthesized by manipulating the initial conditions with a diluted material system. It was found that the ultrasamll MOF nanodots had a highly selective interaction with Fe 3+ and showed a specific blue colorimetric change in aqueous solution. The highly dispersive nature in aqueous solution and high surface-to-volume ratio help MOF-74 nanodots closely interact with the targeted Fe 3+ ions with a low limit of detection of 1.04 μM and a fast response within seconds. Finally, we demonstrate that the selective Fe 3+ sensing mechanism of Zn-MOF-74 nanodots is due to the selective framework disruption and the formation of Fe-DOBDC salt complex with blue color. It is the first report of nanoscale MOF based colorimetric Fe 3+ sensor with low limit of detection (LOD) comparable even to fluorescent MOF based Fe 3+ sensors, which could be easily observed by naked-eye without expensive fluorescence apparatuses. The good colorimetric stability in aqueous environment, low limit of detection, rapid response, and nanosize nature enable this MOF nanodot to be a good Fe 3+ sensing probe for biological and environmental sensing applications.

Nucleic acid testing (NAT) based methods are more sensitive and specific, and are preferred over enzyme immunoassays. Different NAT based protocols have been designed to detect multiple pathogens in order to reduce the inherent high cost for detection. However, these assays do not reliably detect a large number of pathogens at once. In this report, a DNA hybridization based chemiluminescence detection method has been proposed for reliable detection of multiple pathogens. The idea was practically demonstrated by carrying out simultaneous extraction and amplification of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV-1 group M, herein referred to as HIV) through the one step multiplex reverse transcription polymerase chain reaction (RT-PCR). A detailed study was conducted to optimize the factors which could affect the chemiluminescence signal. The probes for HBV, HCV, and HIV demonstrated higher specificity by only capturing their respective target sequence. 10 viral copies per mL of serum were detected in the monoplex detection protocol for HBV, HCV, and HIV, respectively. However, when the sensitivity of each virus was analyzed in the presence of higher loads of other viruses in the multiplex detection assay, the assay finally detected 10 HBV copies, 10 HCV copies, and 100 HIV copies per microliter of serum. The use of silica modified magnetic nanoparticles during nucleic acid extraction and carboxyl coated magnetic nanoparticles during the chemiluminescence step can help modify this system into an automated platform for high throughput applications.

Herein, a dual-modal fluorescent/colorimetric “Signal-On” nanoprobe based on PCN-222 nanorods (NRs) toward phosphate was proposed for the first time. Due to the high affinity of the zirconium node in PCN-222 NRs for phosphate, the structure collapse of PCN-222 NRs was triggered by phosphate, resulting in the release of the tetrakis­(4-carboxyphenyl)­porphyrin (TCPP) ligand from PCN-222 NRs as well as the enhancement of fluorescence and absorbance signals. The PCN-222 NR-based nanoprobe could be employed for phosphate detection over a wide concentration range with a detection limit down to 23 nM. The practical application of the PCN-222 NR-based nanoprobe in real samples was evaluated. Moreover, benefitting from the good biocompatibility and water dispersibility of PCN-222 NRs, this nanoprobe was successfully employed in the intracellular imaging of phosphate, revealing its promising application in the biological science. The present work would greatly extend the potential of nanostructured MOFs in the sensing and biological fields.

With the help of Fe3O4 nagnetic nanoparticles as a solid carrier and an excellent tool for separation, six SNP loci (rs2279115 of BCL2 gene, rs804270 of NEIL2 gene, rs909253 of LTA gene, rs2294008 of PSCA gene, rs3765524 and rs10509670 of PLCE1 gene) were selected to evaluate their relation to gastric cancer risk. Using two kinds of functionalized magnetic nanoparticles and universal tagged arrays, the whole operation procedure including genome DNA extraction and SNP genotyping was performed. All genotypes and allele frequencies were calculated in the cases and controls respectively to analyze their association with gastric cancer risk. Totally 200 pathological samples and 134 normal control subjects were collected. The results demonstrated that four SNP loci (rs2279115, rs804270, rs909253 and rs3765524) showed a potential association with gastric cancer risk, and the other two (rs2294008, rs10509670) possessed no difference/association among cases and controls.