Analytical Chemistry

Svetlana Kuznetsova has completed his Candidate’s and Doctor’s dissertations at Siberian State University of Science and Technology. She has worked as Chief Researcher at Institute of Chemistry and Chemical Technology SB-RAS, Federal Research Center “Krasnoyarsk Science Center SB RAS” and as Professor of Analytical and Organic Chemistry Department of Siberian Federal University. She has published more than 60 papers inreputed journals and 35 patents an invention.

Extractive compounds of outer birch bark contain up to 40% of the mixture of pentacyclic triterpenoids and betulin is the main of them. Medical properties of birch bark extracts have been known for a long time in folk medicine. We suggested new methods of synthesis betulin, allobetulin and acyl derivatives of betulin directly from birch bark without preliminary separation of betulin by combined stages of betulin extraction and its acylation with acetic, propionic or butyric acids. The structure of betulin derivatives have been identified with chromatography and mass spectrometry, FTIR and NMR spectroscopy. It was found that this compound exhibits a broad range of biological activity, including its applications as an anti-cancer agent. The purpose of this work was to obtain fine products from birch bark and study their applications in medical and veterinary sciences.

Peter de Boves Harrington completed his PhD in Analytical Chemistry at University of North Carolina where he worked on “Artificial intelligence methods applied to analytical chemistry”. He then held a Research Professorship at Colorado School of Mines where he developed algorithms for identifying bacteria from their mass spectra. Afterwards, he started his career at OHIO where he now directs the Center for Intelligent Chemical Instrumentation. He has invented many chemometric algorithms that are in use today. Recently, he was honored with the Outstanding Research Award for his college and was named a recipient of China’s 1,000 Talents. He has published more than 170 papers in peer reviewed journals and is a world-renowned speaker.

Many advances in modern society are due to embedded artificial intelligence. Some of these innovations are voice recognition in phones and personal assistants, image recognition for identifying faces in photos, and digital transcription of handwriting. These advances rely on deep neural networks, some of which are efficiently built with layers of restricted Boltzmann machines (RBMs). RBMs have many potential applications in analytical chemistry for finding features in data. They may be used to transform data and improve the performance for classification and calibration. Some examples will demonstrate the improvement form quantifying fat, moisture, and protein content using nearinfrared spectroscopy. Classification of spectra from botanical materials such as cannabis or tea is useful for authentication. The use of RBMs to improve the classification results also shall be demonstrated.

Beibei Zhang has completed his Master’s degree at Henan Agricultural University. He is a Doctor of the State Key Laboratory of Bioelectronics, Southeast University, a double first-rate university with world first-rate disciplines. He has published several papers in reputed journals with impact factor more than 15.

This study develops a new method for detecting target DNA based on Cas9 nuclease, which was named as CARP, representing Cas9/sgRNAs-Associated Reverse PCR. This technique detects target DNA in three steps: cleaving the detected DNA sample with Cas9 in complex with a pair of sgRNAs specific to target DNA; ligating the cleaved DNA with DNA ligase and; amplifying target DNA with PCR. In the ligation step, the Cas9-cut target DNA was ligated into intramolecular circular or intermolecular concatenated linear DNA. In the PCR step, the ligated DNA was amplified with a pair of reverse primers. The technique was verified by detecting HPV16 and HPV18 L1 genes in nine different human papillomavirus (HPV) subtypes. The technique also detected the L1 and E6-E7 genes of two high-risk HPVs, HPV16 and HPV18, in the genomic DNA of two HPV-positive cervical carcinoma cells (HeLa and SiHa), in which no L1 and E6-E7 genes were detected in the HPV-negative cervical carcinoma cell, C-33a. By performing these proof-of-concept experiments, this study provides a new CRISPR-based DNA detection and typing method. Especially, the CARP method verified by this study is ready for the clinical HPV detection.

Shuyan Zhang has completed his Master’s degree from Zhejiang University. He is a Doctor of State Key Laboratory of Bioelectronics, Southeast University, China.

It has been well-known that over activation of NF-κB has close relationship with hepatitis and hepatocellular carcinoma (HCC). However, the complete and exact underlying molecular pathways and mechanisms still remain not fully understood. By manipulating NF-κB activity with its recognized activator TNFα and using ChIP-seq and RNA-seq techniques, this study identified 699 NF-κB direct target genes (DTGs) in a widely used HCC cell line, HepG2, including 399 activated and 300 repressed genes. In these NF-κB DTGs, 216 genes (126 activated and 90 repressed genes) are among the current HCC gene signature. In comparison with NF-κB target genes identified in LPS-induced THP-1 and TNFα-induced HeLa cells, only limited numbers (24-46) of genes were shared by the two cell lines, indicating the HCC specificity of identified genes. Functional annotation revealed that NF-κB DTGs in HepG2 cell are mainly related with many typical NF-κB-related biological processes including immune system process, response to stress, response to stimulus, defense response, and cell death, and signaling pathways of MAPK, TNF, TGF-beta, Chemokine, NF-kappa B, and Toll-like receptor. Some NF-κB DTGs are also involved in Hepatitis C and B pathways. It was found that 82 NF-κB DTGs code secretory proteins, which include CCL2 and DKK1 that have already been used as HCC markers. Finally, the NF-κB DTGs were further confirmed by detecting the NF-κB binding and expression of 14 genes with ChIP-PCR and RT-PCR. This study thus provides a useful NF-κB DTG list for future studies of NF-κB-related molecular mechanisms and theranostic biomarkers of HCC.

Haojun Jin completed his Bachelor degree in Applied Chemistry in 2008 from Nanjing Agricultural University. He completed his Master degree in Organic Chemistry in 2011 from Nanjing Tech University. In 2013, he started his Doctoral program in State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, supervised by Professor Qingjiang Sun. As planned, he will complete Doctoral degree in 2018. His dissertation mainly focuses on design and construction of indicator displacement assay, based quantum dots-ligand probes, which are applicable for biomarkers. Until now, he has authored three papers in the esteemed international journals.

Indicator displacement assay (IDA) have attracted tremendous interest recently because of their advantages of improved selectivity, high sensitivity and visibility for detection of diverse analytes such as anions, amino acids, saccharides and other functional group molecules. With a configuration of indicator-receptor, the analyte is detectable upon its competitive binding with receptor, thus giving rise to a new signal for the released indicator. Quantum dots (QDs) are a class of inorganic fluorophores with high fluorescence quantum yields, size-tunable narrow emission, and exceptional resistance to photo bleaching. Therefore, the QDs are one of the best candidates to serve as indicators in IDAs. In this work, we report quantum dots-ligand fluorescent probes for sensitive and selective detection of biomarkers, including G-quadruplex and avidin, based on IDA. In the IDA approaches, red-emission quantum dots (rQDs) deposited on silica coated green-emission quantum dots (gQDs) are indicators, while ligands (DI for G-quadruplex and PB for avidin) are receptors. The non-aqueous soluble receptors are facilely attached onto the surface of rQDs via phase transfer, and inducing the fluorescence quenching of rQDs in the mechanism of charge transfer (CT). As a key element in the IDAs, displacement of the receptors (ligands) can take place in the presence of trace concentrations of biomarkers due to their stronger affinity, breaking up the QDs-ligand complexation. Consequently, theCT processes are eliminated and the fluorescence of rQDs is restored. However, the fluorescence of gQDs stays constant due to the protection of silica in both of the IDAs. By measuring the fluorescent intensities of gQDs and rQDs, the ratiometric fluorescent response, which is extremely useful for improving the sensitivity and reliability, is achieved. Moreover, variations of dual-emission intensity ratios in the IDAs result in the continuous solution color changes, with benefits of which, naked-eye quantifications of the biomarkers are realized.

Xiaojun Qu completed his Bachelor degree and Master degree from College of Veterinary Medicine-Northwest A&F University, China in 2012. In 2014, he started his Doctoral program at State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering-Southeast University, supervised by Professor Qingjiang Sun. As planned, he will complete his Doctoral degree in 2019. His dissertation mainly focuses on the isothermal amplification reaction on different kinds of quantum dot-encoded bead, which are applicable for ultrasensitive detection of biological molecules. Until now, he has joined and finished two projects and has co-authored three papers on the esteemed international journals.

MicroRNAs (miRNAs) are a group of small size (19–25 nucleotides in length), non-coding RNAs that play regulating roles in many critical biological processes. Recently, accumulating evidence indicates that the aberrant expression of miRNAs is associated with cancer initiation, tumor stage. Thus, miRNAs have been regarded as bio-markers in cancer diagnose. However, the unique characteristics of miRNA, such as their small size, sequence homology among family members, and low abundance, make miRNA more challenging to be analyzed. This article report a protocol of direct implementation of nicking enzyme assisted strand displacement amplification (SDA) on quantum dot-encoded core-shell silica beads (Qbead) and its application for multiplexed assay of human liver carcinoma miRNAs. Qbeads with remarkably improved chemical and photo-stability allows efficient bio-conjugation, hybridization and SDA on the surface. Multifunctional hairpin probes were used, which contain capture sequence specific target binding, nicking enzyme recognition site for the exponential amplification, the G-rich segment as the signal reporter with [Ru(bpy)2(DI)]2+ (Ru-DI), and 3’-end sequence triggering the strand-displacement amplification reaction. By the presence of target and enzyme, using molecular switch Ru-DI, the bead-SDA assay significantly improves the detection sensitivity. A dynamic range of 5 logs and a detection limit of 0.5 fM are achieved, owing to SDAinduced fluorescence signal amplification. More importantly, the SDA on Qbead results in color difference amplification allows color analysis be a conceivable quantification method for the Qbeads-based assay. With benefits of SDA-induced color difference amplification, quantify multiplex miRNAs in cancer cell lysates realized. The Qbead-SDA assay with color analysis could potentially enable the development of point-ofcare diagnostics platforms.

Feature extraction method for spectroscopy is essential for prediction and classification of mixture of compound material. Supervised preserve embedding method is applied for near-infra red or Raman spectra, and the accuracy of geographical origin of agricultural samples enhances. For precision, kernel-based calibration models are combined with multivariate feature selection. Kernel partial least square method and kernel-based support vector regression method are proposed for the specific chemical compositions.

Philiswa N Nomngongo completed her PhD in Chemistry (specializing in Analytical Chemistry) and Post-doctoral studies from University of Johannesburg, South Africa. She has worked as a Lecturer and Professor of Analytical Chemistry at University of Johannesburg. Her main research objective is to develop and apply different sample preparation methods for extraction and pre-concentration of trace organic and inorganic analytes in different sample matrices prior to the chromatographic or spectrometric determination. Her research also focuses on the application of nanotechnology for environmental pollution monitoring, desalination and water treatment. She has published more than 40 papers in highly rated and high impact international journals.

A rapid and effective ultrasonic assisted-solid phase micro-extraction (UA-DSPME) was developed for the preconcentration of thallium in real water samples. The ZnOZrO2@ AC composite functionalized with 1-(2-pyridylazo)- 2-naphthol (PAN) was used as an adsorbent and the target analyte was quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). The morphological, crystalline physical and chemical properties of the composite were characterized by scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM) and X-ray powder diffraction (XRD). The two-level fractional factorial design and response surface methodology were used to optimize experimental parameters affecting the pre-concentration procedure. Under optimum conditions, the enrichment factor (EF), limits of detection (LOD) and quantification (LOQ) were found to be 112, 0.25 ng L−1, and 0.84 ng L−1, respectively. Furthermore, intra-day and inter-day precisions expressed in terms of relative standard deviation (RSD) were found to be 2.4% and 4.3%, respectively. Moreover, the linear dynamic range was between LOQ and 350 μg L−1 with the correlation coefficient of 0.9966.

Vusumzi E Pakade is a Professor at Vaal University of Technology, South Africa. He has been working in the university from many years.

Activated carbons derived from macadamia nutshell powderwere subjected to secondary modification by various concentrations of mineral acid. Subsequently, subjected to surface imprinting for the recognition of Cr(III). In a separate study, polymeric membrane sheets were modified by surface imprinting for Cr(III) removal. Non-imprited versions of both formats were prepared to use as controls. It has been noted that during removal of Cr(VI) by activated carbons (AC), part of Cr(VI) is reduced to Cr(IIII) and in turn not adsorbed on the surface. Therefore, the current study seeks to address the un-adsorbed Cr(III) by introducing the selective imprinting method for the recognition of Cr(III). FTIR, TGA, SEM revealed that the acid treatment modified the surface of the adsorbent. Compared to the raw AC the acid functionalized AC showed acidic characteristic bands. Fourier Transform Infrared Spectroscopy (FTIR) detected the presence of C=O, O-H and COO- functional groups on the surface of the modified AC. Brunauer-Emmett-Teller (BET) showed an increase in surface area from 549 to 582 m2 g-1 following treatment. Different experimental parameters were optimized for effective adsorption of Cr(VI). The optimal parameters were as follows: pH 1, solution concentration 100 mg L-1, reaction time 8 hours and adsorbent dosage 0.32 g indicating that adsorption is strongly dependent on the mentioned parameters.

Moustafa Khalifa has completed his PhD in Chemistry from Institute of Industrial Organic Chemistry, Poland Academy of Science, Warsaw, Poland, in 1982. He is a Lab Consultant for Drug and Food Quality Control Laboratories, Ministry of Health, Kuwait and has been serving as a Professor of Pesticides Chemistry and Analysis at Kafrelsheikh University, Egypt.

It is well known that there are currently three synthetic phosphodiesterase type 5 (PDE-5) inhibitors, sildenafil citrate (brand name Viagra) (S), vardenafil hydrochloride (brand name Levitra) (V) and tadalafil (brand name Cialis) (T) that have been evaluated as an orally effective drugs for the treatment of ED since 1998. An adulteration of “natural” herbal products with at least one of the previously mentioned synthetic PDE- 5 inhibitors or their structurally analogue has been reported since 2001. It is true that adulteration of natural herbal products with undeclared synthetic PDE-5 inhibitors, or their structurally analogues is a growing trend and poses a health threat to consumers. The aim of this study was directed to investigate the presence of synthetic PDE-5 analogues illegally adulterated in natural herbal products intended to be used for improve male sexual potency in Kuwait. The samples evaluated in this study consisted of a pre-market herbal product (tablet or capsules forms) which has been a subject for registration by Kuwait Drug and Food Administration (KUDFA) as natural herbal products for improving sexual performance for man in the period from 2003 to 2012. In our laboratories identification of these analogues were done using, TLC, HPLC—PDA, HPLC— PDA¾ESI(+)¾MS and HPLC¾PDA¾ESI¾(+)¾MS/ MS HRMS, and NMR as analytical tools. Our results were indicated the presence of hydroxyhomosildenafil and thiosildenafil as analogous for sildenafil and aminotadalafil as analogue of tadalafil, that were adulterated in some investigated samples of herbal products. According to KUDFA rules all adulterated herbal products have been cancelled from registration and banned to be used by men in Kuwait.