Colorimetric Immunological Paper-based Assay for Exosome Detection

This paper reports the development of colorimetric immunological paper-based assay for exosome detection. The paper-based device was fabricated with lamination technique for easy handling and create hydrophilic/hydrophobic region for analytical paper-based devices. Exosome-specific antibody was coated onto the paper-based devices as a biosensing platform to detect exosome sample from the cell culture media. This assay employed a colorimetric reaction which is followed by reaction between horseradish peroxidase (HRP) and 3,3’,5,5’-tetramethylbenzidine substrate (TMB). The colorimetric readout was qualitatively evaluated by naked eyes and was quantitatively assessed by image processing software. The result indicated that this assay faces many challenges. First, the exosome concentration may be inadequate to reach detectable range. Second, high background signal due to non-specific binding on the platform results in lack of sensitivity for exosome detection. Therefore, modification on the paper should promote protein binding for specific target and prevent non-specific binding to reduce the high background signal.

Hg2+ Detection with Rational Design of DNA-Templated Fluorescent Silver Nanoclusters

Atomically precise silver nanoclusters (AgNCs) are small nanostructures consisting of only a few atoms of silver. The combination of AgNCs with cytosine-rich single-stranded oligonucleotides results in DNA-templated silver nanoclusters (DNA-AgNCs). DNA-AgNCs are highly luminescent and can be engineered with reproducible and unique fluorescent properties. Furthermore, using nucleic acids as templates for the synthesis of AgNCs provides additional practical benefits by expanding optical activity beyond the visible spectral range and creating the possibility for color tunability. In this study, we explore DNA oligonucleotides designed to fold into hairpin-loop (HL) structures which modulate optical properties of AgNCs based on the size of the loop containing different number of cytosines (HL-CN). Depending on the size of the loop, AgNCs can be manufactured to have either single or multiple emissive states. Such hairpin-loop structures provide an additional stability for AgNCs and further control over the base composition of the loop, allowing for the rational design of AgNCs’ optical properties. We demonstrate the potential of AgNCs in detecting Hg2+ by utilizing the HL-C13 design and its variants HL-T2C11, HL-T4C9, and HL-T6C7. The replacement of cytosines with thymines in the loop was intended to serve as an additional sink for mercury ions extending the detectable range of Hg2+. While AgNC@HL-T0C13 exhibits an interpretable quenching curve, AgNC@HL-T6C7 provides the largest detectable range of Hg2+. The results presented herein suggest that it is possible to use a rational design of DNA-AgNCs based on the composition of loop sequence in HL structures for creating biosensors to detect heavy metals, particularly Hg2+.

Identification of the Colletotrichum species associated with mango diseases and a universal LAMP detection method for C. gloeosporioides species complex

The Colletotrichum gloeosporioides species complex contains plant pathogens linked to Anthracnose diseases afflicting various crops. In this study, we designed a loop-mediated isothermal amplification assay (LAMP) primer set based on calmodulin gene coding region sequences from taxonomically authorized isolates of species from this complex to rapidly detect the presence of fungi associated with Anthracnose diseases. This test can be employed at any point between cultivation and sale. Moreover, we examined the specificity and detectable range of this primer set using isolates selected from species of the genus Colletotrichum. This test was able to specifically detect members of the C. gloeosporioides species complex, including C. gloeosporioides, C. aotearoa, C. fructicola, C. horii, C. kahawae, C. musae, C. siamense, C. theobromicola, and C. tropicale. Key Words: Anthracnose, diagnosis, phylogeny, plant disease

Location tracking using LoRa

<span>Local area network (LAN) as Bluetooth, WiFi and ZigBee are well established technology. The biggest problem with many LAN is the battery consumption and short ranges link budgets. LoRa is a new, private, unlicensed and spread spectrum modulation technique which allows sending low rates at extremely long ranges with minimal power consumption. More importantly, there is no access fee associated with this type of wireless technology. The main idea behind this work is to conduct performance and capability analysis of a currently available LoRa transceiver. We develop a location monitoring system using LoRa and global positioning system (GPS) module and we analyze the detectable range of its data, its battery consumption as well as received signal strength indicator (RSSI). Our deployment experiment demonstrates that the sy<span>stem is able to detect the transmitted data within 290 meters of distances. Using 6 volts of battery AA, the transmission of data still occurred after 24 hours</span>. <span>This project is emphasized a location monitoring system that provide low power usage</span> but long range.</span>

Long-Term Tri-Modal In Vivo Tracking of Engrafted Cartilage-Derived Stem/Progenitor Cells Based on Upconversion Nanoparticles

Cartilage-derived stem/progenitor cells (CSPCs) are a potential choice for seed cells in osteal and chondral regeneration, and the outcomes of their survival and position distribution in vivo form the basis for the investigation of their mechanism. However, the current use of in vivo stem cell tracing techniques in laboratories is relatively limited, owing to their high operating costs and cytotoxicity. Herein, we performed tri-modal in vivo imaging of CSPCs during subcutaneous chondrogenesis using upconversion nanoparticles (UCNPs) for 28 days. Distinctive signals at accurate positions were acquired without signal noise from X-ray computed tomography, magnetic resonance imaging, and upconversion luminescence. The measured intensities were all significantly proportional to the cell numbers, thereby enabling real-time in vivo quantification of the implanted cells. However, limitations of the detectable range of cell numbers were also observed, owing to the imaging shortcomings of UCNPs, which requires further improvement of the nanoparticles. Our study explores the application value of upconversion nanomaterials in the tri-modal monitoring of implanted stem cells and provides new perspectives for future clinical translation.

CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITIES OF BEETROOT PEEL.

Proximate, mineral and antioxidant properties of beetroot (Beta vulgaris) peel were investigated using standard analytical techniques. Result for proximate revealed that moisture content was 30.88%, ash content (10.58%), crude fat (3.29%), crude fiber (6.98%), crude protein (4.10%) and carbohydrate (44.17%). The mineral composition (mg/g) also showed that sodium was 4.17%, iron (26.46%), copper (0.21%), magnesium (5.91%), potassium (13.82%) and phosphorus (11.57%) while zinc and calcium were not at detectable range of AAS. There was no activity for its antioxidant property. The results obtained from this analysis shows that Beetroot peel is a good source of carbohydrates, protein, ash, fiber, lipid and moisture, it also contained some mineral contents such as copper, phosphorous and iron which are required by the body to function effectively. Its consumption is therefore advertised instead of regarding it as a waste material. Keywords: antioxidant, investigation, mineral, peel, proximate

ELISA for the Detection of the Prohibited Doping Agent Higenamine

Higenamine is a natural benzyltetrahydroisoquinoline alkaloid produced by various plants. In the World Anti-Doping Agency report of 2020, higenamine is classified as a class S3 (selective and nonselective β2-agonist) prohibited substance. To minimize the problems resulting from the misuse of higenamine-containing products as well as from the abuse of doping agents in sport, numerous higenamine-detection methods have been investigated. In the present study, a monoclonal antibody against the (S)-enantiomer of higenamine was successfully produced and applied in the indirect competitive ELISA to detect the content of (S)-higenamine in plant samples and related products. By immunizing BALB/c mice with higenamine-BSA, the aforementioned monoclonal antibody was produced even when the hapten number, which was the higenamine molecules conjugated to the BSA molecule, was relatively low (approximately 4). The MAb was characterized and utilized in the established icELISA assay with a detectable range of 7.81 – 125 ng/mL. The assay limit of detection (LOD) was 4.41 ng/mL, indicating higher sensitivity than the conventional HPLC-UV methods. Various validation processes demonstrated that icELISA was precise, with the maximum CV (%) of the intra- and inter-assays of 11.58% and 10.18%, respectively. Moreover, the assay was accurate, with the recovery rates of spiked (S)-higenamine ranging from 82% to 113%, and sufficiently reliable for the detection of (S)-higenamine in various kinds of samples. Notably, the present study describes the first immunoassay for (S)-higenamine.

Preliminary Screening of Polybrominated Diphenyl Ethers (PBDEs); Decabromodiphenyl Ether (BDE-209) and Tetrabromobisphenol-A (TBBPA) Flame Retardants in Municipal Dumpsite in Delta State, Nigeria

Aims: This study is aimed at determining the concentration of two widely used BFRs; Decabromodiphenyl Ether (BDE-209) and Tetrabromo Bisphenol-A (TBBPA) in sediment and leachate samples. Place and Duration of Study: Field sampling were carried out from five major dumpsites around Warri Municipality, Delta State, Nigeria. Analyte extraction was done in 2017 at the Science laboratory, Federal University of Petroleum Resources, Effurun Delta State, Nigeria and quantification done in Switzerland by Bachema Analytical Laboratories in 2017. Methods: Three soil samples were collected from each site 15cm from the soil surface. Also, three leachate samples from three different trial pits done for each site. Collected soil samples were stored in glass bottles and labelled. While the leachate samples are stored using glass containers and labelled. The BFRs were extracted using Aceton and cyclohexane for each soil matrix and cyclohexane for the leachate samples, then the extract was analysed using GC coupled with an ECD supplied by Thermo Trace GC Ultra, Italy. Results: The results showed the average concentration for TBBPA in the sediments was 0.0234 g/kg and that of the BDE-209 was recorded as 0.1828 g/kg. Results from the leachate sample were below the detectable range of the analytical equipment, TBBPA (0.02 g/kg) and BDE (0.1 g/kg). There is no statistical difference between the mean concentration of TBBPA for the sediment in each of the locations (P>.05) and no difference (P>.05) for BDE-209 for the sediment in each of the locations (P>.05). Conclusion: Findings from this study holds that the concentration of TBBPA and BDE-209 in sediment is higher when compared with concentrations presented in other literatures studied in this report and this calls for immediate action due to the health risk associated with exposure in these municipalities.