Analyst Blog

Differentiating quadruplexes from duplexes using silver nanoparticles and SERS

A promising drug target and ligand-binding site, G-quadruplexes form via Hoogsteen hydrogen bonding in guanine bases. These quartets are rich in guanine and are stabilized through π-π stacking interactions and a cation such as potassium or sodium. As researchers explore new compounds to target this region to treat diseases such as cancer, the structure of these quadruplexes and their response to ligands compared to standard DNA remains understudied. 

Researchers at the University of Strathclyde have used the sensitivity of surface-enhanced Raman spectroscopy (SERS) to detect the formation of G-quadruplexes in the presence of stabilizing ligands and silver nanoparticles. They successfully differentiated the quadruplex DNA structure from the duplex based on the SERS signal, and demonstrated the capability of SERS in identifying higher order DNA structures. To read more about the qualitative detection of these structures, click the link below. It will be free to read until June 30. 

Graphene-polyfuran hybrids for Hg sensing

Commonly associated with dental fillings, mercury has a wide range of industrial and domestic applications. However, it can be toxic to humans and the environment even in small concentrations, and has been linked to a number of fatal diseases including pulmonary edema and cyanosis.

Previously developed methods of mercury detection include photochemical, colorimetric and oligonucleotide-based approaches. However, these methods can be slow, expensive and associated with low sensitivity and selectivity for the analyte. Graphene composite materials, with their unusual and enhanced conductivity properties, are an attractive prospect for metal ion analysis.

Researchers led by Professor Jyongsik Jang at the Seoul National University, Korea, have developed a new class of graphene oxide-polyfuran nanotube hybrids. In this “HOT” Analyst paper, the authors test the potential of their graphene-based materials as high performance sensors for mercury ion detection. This method has proved to be highly selective for Hg²⁺ over other metal ions and has excellent sensitivity even at low mercury concentrations.

This article will be free to read until 30th June.

High-performance Hg²⁺ FET-type sensors based on reduced graphene oxide–polyfuran nanohybrids
Jin Wook Park, Seon Joo Park, Oh Seok Kwon, Choonghyen Lee and Jyongsik Jang
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00403E

Take a look at our new HOT articles just published in Analyst and free for you for the next couple of weeks:

Two-dimensional MoS₂ nanosheets as a capillary GC stationary phase for highly effective molecular screening
Jia Jia, Fujian Xu, Shanling Wang, Xue Jiang, Zhou Long and Xiandeng Hou 
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00332B, Communication

On the optimization of operating conditions for Taylor dispersion analysis of mixtures
Hervé Cottet, Jean-Philippe Biron and Michel Martin  
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00192C, Paper

Capillary electrophoresis based on the nucleic acid detection in the application of cancer diagnosis and therapy
Dong-Sheng Lian and Shu-Jin Zhao  
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00400K, Minireview

Micropatterning neuronal networks
Heike Hardelauf, Sarah Waide, Julia Sisnaiske, Peter Jacob, Vanessa Hausherr, Nicole Schöbel, Dirk Janasek, Christoph van Thriel and Jonathan West  
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00608A, Paper

BRET-linked ATP assay with luciferase
Golnaz Borghei and Elizabeth A. H. Hall  
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00436A, Paper

An ultra-high-throughput spiral microfluidic biochip for the enrichment of circulating tumor cells
Majid Ebrahimi Warkiani, Bee Luan Khoo, Daniel Shao-Weng Tan, Ali Asgar S. Bhagat, Wan-Teck Lim, Yoon Sim Yap, Soo Chin Lee, Ross A. Soo, Jongyoon Han and Chwee Teck Lim  
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00355A, Paper

A purge and trap integrated microGC platform for chemical identification in aqueous samples
Muhammad Akbar, Shree Narayanan, Michael Restaino and Masoud Agah  
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00254G, Paper

Hybridization chain reaction-based fluorescence immunoassay using DNA intercalating dye for signal readout
Yan Deng, Ji Nie, Xiao-hui Zhang, Ming-Zhe Zhao, Ying-Lin Zhou and Xin-Xiang Zhang  
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00190G, Paper

Evaluating the sensitivity of hybridization-based epigenotyping using a methyl binding domain protein
Brandon W. Heimer, Tatyana A. Shatova, Jungkyu K. Lee, Kaja Kaastrup and Hadley D. Sikes  
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00667D, Communication

Qualitative SERS analysis of G-quadruplex DNAs using selective stabilising ligands
K. Gracie, V. Dhamodharan, P. I. Pradeepkumar, K. Faulds and D. Graham 
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00551A, Paper

A water-soluble sulfonate-BODIPY based fluorescent probe for selective detection of HOCl/OCl in aqueous media
Jiyoung Kim and Youngmi Kim 
Analyst, 2014,139, 2986-2989
DOI: 10.1039/C4AN00466C, Communication

A coumarin-based fluorescent probe for differential identification of sulfide and sulfite in CTAB micelle solution
Haiyu Tian, Junhong Qian, Qian Sun, Chenjia Jiang, Runsheng Zhang and Weibing Zhang 
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00478G, Paper

Upconversion nanoparticles for ratiometric fluorescence detection of nitrite
Junfen Han, Cheng Zhang, Fei Liu, Bianhua Liu, Mingyong Han, Wensheng Zou, Liang Yang and Zhongping Zhang 
Analyst, 2014,139, 3032-3038
DOI: 10.1039/C4AN00402G, Paper

Split aptazyme-based catalytic molecular beacons for amplified detection of adenosine
Jin Huang, Yong He, Xiaohai Yang, Kemin Wang, Ke Quan and Xiaoping Lin 
Analyst, 2014,139, 2994-2997
DOI: 10.1039/C4AN00454J, Communication

High-performance Hg²⁺ FET-type sensors based on reduced graphene oxide–polyfuran nanohybrids
Jin Wook Park, Seon Joo Park, Oh Seok Kwon, Choonghyen Lee and Jyongsik Jang 
Analyst, 2014, Advance Article
DOI: 10.1039/C4AN00403E, Communication

One-step prepared fluorescent copper nanoclusters for reversible pH-sensing
Wei Wang, Fei Leng, Lei Zhan, Yong Chang, Xiao Xi Yang, Jing Lan and Cheng Zhi Huang  
Analyst, 2014,139, 2990-2993
DOI: 10.1039/C4AN00113C, Communication

When a drop is applied to a surface and dries, a number of factors control the formation of the dried drop. Essentially as the fluid or solvent evaporates, capillary flow transports molecules to the contact line of the drop with the surface and the drop dries as a ring with components coarsely separated, like a coffee ring.

Drop deposition of biofluids is being investigated worldwide as a possible diagnostic tool. However, the parameters that affect the formation of the biofluids coffee ring are not fully understood and this is a barrier that needs to be overcome in order to realise the clinical potential of drop deposited biofluids. Drop deposition is particularly well suited for examining low abundance biofluids such as tears and synovial fluids but is also widely investigated for blood plasma and serum.

A team of US researchers, based at the University of Michigan, have recently published a HOT article characterising biofluids prepared by drop deposition. The researchers studied two model biofluids, blood plasma and synovial fluid, when deposited onto slightly hydrophilic substrates with a contact angle of 50 – 90 degrees. The researchers showed that under most circumstances the model biofluids followed the piling model, as suggested by Deegan et al. and that an increased understanding of the time-dependent rheology and intermolecular forces that occur during evaporation would provide a better approximation. Importantly, from molecular analysis of the drop via Raman spectroscopy, that whilst the morphology of the dried drop changed the chemical composition and molecular structure of the dried proteins within the outer ring were unaffected.