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paper based assay

Yanlin Ma, Yang Deng, Zhenbo Xu, Junyan Liu, Jianjun Dong, Hua Yin, Junhong Yu, Zongming Chang, Dongfeng Wang
The spoilage of beer by bacteria is of great concern to the brewer as this can lead to turbidity and abnormal flavors. The polymerase chain reaction (PCR) method for detection of beer-spoilage bacteria is highly specific and provides results much faster than traditional microbiology techniques. However, one of the drawbacks is the inability to differentiate between live and dead cells. In this paper, the combination of propidium monoazide (PMA) pretreatment and conventional PCR had been described. The established PMA-PCR identified beer spoilage Lactobacillus brevis based not on their identity, but on the presence of horA gene which we show to be highly correlated with the ability of beer spoilage LAB to grow in beer...
June 3, 2017: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
Lingyi Lan, Yao Yao, Jianfeng Ping, Yibin Ying
Food chemical contaminant is a major factor to cause foodborne diseases and can do harm to human health. Hence, to develop robust, easy, and sensitive methods for rapid evaluation of food chemical contaminants is highly desirable. Nanomaterial-based optical aptasensors combined with the advantages of the high selectivity of optical detection techniques, excellent stability of aptamer, and the unique properties of nanomaterials have been recognized as useful tools for routine biosensing applications. The recent progress in nanomaterial-based optical aptamer assays to determine food chemical contaminants including heavy metals, toxins, pesticides, and antibiotics are presented in this paper...
June 20, 2017: ACS Applied Materials & Interfaces
C Chad Lloyd, Matthew W Boyce, Matthew R Lockett
To elucidate the chemical and environmental conditions that promote invasion of cancer cells, an assay is needed in which the chemical landscape of a tumor-like environment can be experimentally manipulated and probed. The three-dimensional paper-based invasion assays described here simulate poorly vascularized tissue and allow the invasion of cancerous cells to be visualized and quantified. These cultures are easy to assemble and allow multiple invasion assays to be performed in parallel. By using different materials to control gradients formed across the culture, the chemotactic potential of small molecules can be evaluated in a more representative tissue microenvironment...
June 19, 2017: Current Protocols in Chemical Biology
Max M Gong, David Sinton
Infectious diseases are a major global health issue. Diagnosis is a critical first step in effectively managing their spread. Paper-based microfluidic diagnostics first emerged in 2007 as a low-cost alternative to conventional laboratory testing, with the goal of improving accessibility to medical diagnostics in developing countries. In this review, we examine the advances in paper-based microfluidic diagnostics for medical diagnosis in the context of global health from 2007 to 2016. The theory of fluid transport in paper is first presented...
June 19, 2017: Chemical Reviews
Junjie Chi, Bingbing Gao, Mi Sun, Fengling Zhang, Enben Su, Hong Liu, Zhongze Gu
We report an enzyme-link immunosorbent assay (ELISA) based on patterned pseudo-paper that is made of photonic nitrocellulose for highly sensitive fluorescent bioanalysis. The pseudo-paper is fabricated using self-assembled monodisperse SiO2 nanoparticles that are patterned on a polypropylene substrate as template. The self-assembled nanoparticles have a close-packed hexagonal (opal) structure, so the resulting nitrocellulose has a complementary (inverse opal) photonic structure. Owing to the slow-photon effect of the photonic structure, fluorescent emission for ELISA is enhanced by up to 57-fold without increasing the assay time or complexity...
June 16, 2017: Analytical Chemistry
Rachael M Kenney, C Chad Lloyd, Nathan A Whitman, Matthew R Lockett
Cellular invasion is the gateway to metastasis, which is the leading cause of cancer-related deaths. Invasion is driven by a number of chemical and mechanical stresses that arise in the tumor microenvironment. In vitro assays are needed for the systematic study of cancer progress. To be truly predictive, these assays must generate tissue-like environments that can be experimentally controlled and manipulated. While two-dimensional (2D) monolayer cultures are easily assembled and evaluated, they lack the extracellular components needed to assess invasion...
June 16, 2017: Chemical Communications: Chem Comm
Fariba Ghaderinezhad, Reza Amin, Mikail Temirel, Bekir Yenilmez, Adam Wentworth, Savas Tasoglu
Paper-based micro analytical devices offer significant advantages compared to the conventional microfluidic chips including cost-effectiveness, ease of fabrication, and ease of use while preserving critical features including strong capillary action and biological compatibility. In this work, we demonstrate an inexpensive, rapid method for high-throughput fabrication of paper-based microfluidics by patterning hydrophobic barriers using a desktop pen plotter integrated with a custom-made, low-cost paper feeder...
June 15, 2017: Scientific Reports
Cheonjung Kim, Yong Kyoung Yoo, Sung Il Han, Junwoo Lee, Dohwan Lee, Kyungjae Lee, Kyo Seon Hwang, Kyu Hyoung Lee, Seok Chung, Jeong Hoon Lee
Paper-based analytical devices (e.g. lateral flow assays) are highly advantageous as portable diagnostic systems owing to their low costs and ease of use. Because of their low sensitivity and detection limits for biomolecules, these devices have several limitations in applications for real-field diagnosis. Here, we demonstrate a paper-based preconcentration enhanced lateral flow assay using a commercial β-hCG-based test. Utilizing a simple 9 V battery operation with a low power consumption of approximately 81 μW, we acquire a 25-fold preconcentration factor, demonstrating a clear sensitivity enhancement in the colorimetric lateral flow assay; consequently, clear colors are observed in a rapid kit test line, which cannot be monitored without preconcentration...
June 14, 2017: Lab on a Chip
Rodrigo Goncalves, Katherine DeSchryver, Cynthia Ma, Yu Tao, Jeremy Hoog, Maggie Cheang, Erika Crouch, Neha Dahiya, Souzan Sanati, Michael Barnes, Luis Otávio Zanatta Sarian, John Olson, Donald Craig Allred, Matthew J Ellis
PURPOSE: The recent publication of the ACOSOG Z1031 trial results demonstrated that Ki-67 proliferation marker-based neoadjuvant endocrine therapy response monitoring could be used for tailoring the use of adjuvant chemotherapy in ER+HER2-negative breast cancer patients. In this paper, we describe the development of the Ki-67 clinical trial assay used for this study. METHODS: Ki-67 assay assessment focused on reproducing a 2.7% Ki-67 cut-point (CP) required for calculating the Preoperative Endocrine Prognostic Index and a 10% CP for poor endocrine therapy response identification within the first month of neoadjuvant endocrine treatment...
June 13, 2017: Breast Cancer Research and Treatment
Sepeedah Soltanian-Zadeh, Kruthika Kikkeri, Ayesha N Shajahan-Haq, Jeannine Strobl, Robert Clarke, Masoud Agah
Inherent electrical properties of cells can be beneficial to characterize different cell lines and their response to experimental drugs. This paper presents a novel method to characterize the response of breast cancer cells to drug stimuli through use of off-chip passivated-electrode insulator-based dielectrophoresis (OπDEP) and the application of AC electric fields. This work is the first to demonstrate the ability of OπDEP to differentiate between two closely related breast cancer cell lines, LCC1 and LCC9 while assessing their drug sensitivity to an experimental anti-cancer agent, Obatoclax...
June 13, 2017: Electrophoresis
Antoine Hoang, Eugénie Laigre, David Goyard, Eric Defrancq, Françoise Vinet, Pascal Dumy, Olivier Renaudet
Carbohydrate microarrays represent powerful tools to study and detect carbohydrate-binding proteins, pathogens or cells. In this paper, we report two original oxime-based methods to prepare surfaces displaying well-defined structures and valency in a given microspot with improved recognition potency with lectins. In a first "direct" approach, fully synthetic aminooxylated glycoclusters have been coated onto aldehyde-activated SiO2 (silicium substrate doped with 50 nm thermal oxide layer). To improve the preparation of the microarray in terms of rapidity and simplicity and to provide addressable surfaces on which sugars can be linked chemoselectively as clusters at defined plots, a second "indirect" strategy has been developed using successive oxime ligation steps...
June 21, 2017: Organic & Biomolecular Chemistry
Reza Amin, Fariba Ghaderinezhad, Lu Li, Eric Lepowsky, Bekir Yenilmez, Stephanie Knowlton, Savas Tasoglu
There is an unmet need for high-throughput fabrication techniques for paper-based microanalytical devices, especially in limited resource areas. Fabrication of these devices requires precise and repeatable deposition of hydrophobic materials in a defined pattern to delineate the hydrophilic reaction zones. In this study, we demonstrated a cost- and time-effective method for high-throughput, easily accessible fabrication of paper-based microfluidics using a desktop pen plotter integrated with a custom-designed multipen holder...
June 9, 2017: Analytical Chemistry
Phalisteen Sultan, Arif Jan, Qazi Pervaiz
BACKGROUND: Picrorhiza kurroa Royle commonly known as 'Kutki or Kutaki' is an important medicinal plant in Ayurvedic system of medicine and has traditionally been used to treat disorders of the liver and upper respiratory tract. The plant is the principle source of iridoid glycosides, picrosides I, II and kutkoside used in various herbal drug formulations mainly as strong hepatoprotective and immune-modulatory compound. The species has become endangered to near extinction due to the unregulated collection from the wild, slower plant growth and ecological destruction of natural habitats...
December 2016: Botanical Studies (Taipei, Taiwan)
Ali Y Mutlu, Volkan Kılıç, Gizem Kocakuşak Özdemir, Abdullah Bayram, Nesrin Horzum, Mehmet E Solmaz
We report the application of machine learning to smartphone-based colorimetric detection of pH values. The strip images were used as the training set for Least Squares-Support Vector Machine (LS-SVM) classifier algorithms that were able to successfully classify the distinct pH values. The difference in the obtained image formats was found not to significantly affect the performance of the proposed machine learning approach. Moreover, the influence of the illumination conditions on the perceived color of pH strips was investigated and further experiments were conducted to study the effect of color change on the learning model...
June 9, 2017: Analyst
Gilles Cellier, Sandrine Arribat, Frédéric Chiroleu, Philippe Prior, Isabelle Robène
Ralstonia solanacearum is a well-known agricultural and ecological threat worldwide. The complexity of the R. solanacearum species complex (Rssc) represents a challenge for the accurate characterization of epidemiological strains by official services and research laboratories. The majority of protocols only focus on a narrow range of strains; however, this species complex includes strains that represent major constraints and are under strict regulation. The main drawback associated with the current methods of detecting and characterizing Rssc strains is their reliance on combining different protocols to properly characterize the strains at the ecotype level, which require time and money...
2017: Frontiers in Plant Science
Kwi Nam Han, Jong-Soon Choi, Joseph Kwon
In this study, we developed a facile gold nanozyme-based paper chip (AuNZ-PAD) for Hg(2+) detection. This device has the advantages of being simple, rapid, cost effective, sensitive, selective, high throughput, and applicable to onsite detection. The colorimetric mercury assay on the AuNZ-PAD is established based on the enzyme-like catalytic activity of gold nanoparticles promoted by the formation of Au-Hg amalgam, which is correlated to the intensity of the colorimetric response resulting from the catalytic reaction of 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2...
June 5, 2017: Scientific Reports
Dmitriy A Shagin, Irina A Shagina, Andrew R Zaretsky, Ekaterina V Barsova, Ilya V Kelmanson, Sergey Lukyanov, Dmitriy M Chudakov, Mikhail Shugay
The accuracy with which DNA polymerase can replicate a template DNA sequence is an extremely important property that can vary by an order of magnitude from one enzyme to another. The rate of nucleotide misincorporation is shaped by multiple factors, including PCR conditions and proofreading capabilities, and proper assessment of polymerase error rate is essential for a wide range of sensitive PCR-based assays. In this paper, we describe a method for studying polymerase errors with exceptional resolution, which combines unique molecular identifier tagging and high-throughput sequencing...
June 2, 2017: Scientific Reports
Kristian T Madsen, Marianne N Skov, Sabine Gill, Michael Kemp
INTRODUCTION: The enterococci are accountable for up to 20% of all cases of infective endocarditis, with Enterococcus faecalis being the primary causative isolate. Infective endocarditis is a life-threatening infection of the endocardium that results in the formation of vegetations. Based on a literature review, this paper provides an overview of the virulence factors associated with E. faecalis infective endocarditis. Furthermore, it reports the effects of active or passive immunization against some of these involved factors...
2017: Open Microbiology Journal
Eunice Kazue Kano, Chang Chiann, Kazuo Fukuda, Valentina Porta
Bioavailability and bioequivalence study is one of the most frequently performed investigations in clinical trials. Bioequivalence testing is based on the assumption that 2 drug products will be therapeutically equivalent when they are equivalent in the rate and extent to which the active drug ingredient or therapeutic moiety is absorbed and becomes available at the site of drug action. In recent years there has been a significant growth in published papers that use in silico studies based on mathematical simulations to analyze pharmacokinetic and pharmacodynamic properties of drugs, including bioavailability and bioequivalence aspects...
May 23, 2017: Drug Research
Yawen Liu, Zhaozhu Zheng, He Gong, Meng Liu, Shaozhe Guo, Gang Li, Xiaoqin Wang, David L Kaplan
The structure of DNA is susceptible to alterations at high temperature and on changing pH, irradiation and exposure to DNase. Options to protect and preserve DNA during storage are important for applications in genetic diagnosis, identity authentication, drug development and bioresearch. In the present study, the stability of total DNA purified from human dermal fibroblast cells, as well as that of plasmid DNA, was studied in silk protein materials. The DNA/silk mixtures were stabilized on filter paper (silk/DNA + filter) or filter paper pre-coated with silk and treated with methanol (silk/DNA + PT-filter) as a route to practical utility...
May 31, 2017: Biomaterials Science
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