Electrochemical DNA biosensors: a review

Sensor Review ◽  
2019 ◽  
Vol 39 (1) ◽  
pp. 34-50 ◽  
Author(s):  
Bushra Rafique ◽  
Mudassir Iqbal ◽  
Tahir Mehmood ◽  
Muhammad Ashraf Shaheen

Purpose This review aims to focus on recent reported research work on the construction and function of different electrochemical DNA biosensors. It also describes different sensing materials, chemistries of immobilization probes, conditions of hybridization and principles of transducing and amplification strategies. Design/methodology/approach The human disease-related mutated genes or DNA sequence detection at low cost can be verified by the electrochemical-based biosensor. A range of different chemistries is used by the DNA-based electrochemical biosensors, out of which the interactions of nanoscale material with recognition layer and a solid electrode surface are most interesting. A diversity of advancements has been made in the field of electrochemical detection. Findings Some important aspects are also highlighted in this review, which can contribute in the creation of successful biosensing devices in the future. Originality/value This paper provides an updated review of construction and sensing technologies in the field of biosensing.

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Nidhi Mathur ◽  
Anamika Aneja ◽  
P. K. Bhatnagar ◽  
P. C. Mathur

A reliable, fast, and low-cost biosensor for medical diagnostics using DNA sequence detection has been developed and tested for the detection of the bacterium “Bacillus anthracis.” In this sensor, Poly [9,9-di (6,6′- N,N′trimethylammonium) hexylfluorenyl-2, 7-diyl)-alt-co- (1,4-phenylene)] dibromide salt (PFP) has been taken as cationic conjugated polymer (CCP) and PNA attached with fluorescein dye (PNAC∗) as a probe. The basic principle of this sensor is that when aPNAC∗probe is hybridized with a single strand DNA (ssDNA) having complementary sequence, Forster resonance energy transfer (FRET) may take place from PFP to thePNAC∗/DNA complex. If the FRET is efficient, the photoluminescence from the PFP will be highly quenched and that fromPNAC∗will be enhanced. On the other hand, if the DNA sequence is noncomplementary to PNA, FRET will not occur.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
M. Balasubramanian ◽  
Thozhuvur Govindaraman Loganathan ◽  
R. Srimath

Purpose The purpose of this study is to understand the behavior of hybrid bio-composites under varied applications. Design/methodology/approach Fabrication methods and material characterization of various hybrid bio-composites are analyzed by studying the tensile, impact, flexural and hardness of the same. The natural fiber is a manufactured group of assembly of big or short bundles of fiber to produce one or more layers of flat sheets. The natural fiber-reinforced composite materials offer a wide range of properties that are suitable for many engineering-related fields like aerospace, automotive areas. The main characteristics of natural fiber composites are durability, low cost, low weight, high specific strength and equally good mechanical properties. Findings The tensile properties like tensile strength and tensile modulus of flax/hemp/sisal/Coir/Palmyra fiber-reinforced composites are majorly dependent on the chemical treatment and catalyst usage with fiber. The flexural properties of flax/hemp/sisal/coir/Palmyra are greatly dependent on fiber orientation and fiber length. Impact properties of flax/hemp/sisal/coir/Palmyra are depended on the fiber content, composition and orientation of various fibers. Originality/value This study is a review of various research work done on the natural fiber bio-composites exhibiting the factors to be considered for specific load conditions.


2017 ◽  
Vol 29 (6) ◽  
pp. 754-767 ◽  
Author(s):  
Kumar K.V. ◽  
Sampath V.R. ◽  
Prakash C.

Purpose Air permeability of knitted fabrics is normally measured for the samples in their unstretched state. But, this air permeability values indicate the ability of these garments to allow air through them when they are not in use. But, the real-time condition is different and certainly the knitted garments mentioned above will subject to a degree of stretch during their usage. So, the measurement of air permeability under stretch and the fabric properties which would influence the air permeability of weft-knitted fabrics in their stretched state is of paramount importance. The paper aims to discuss these issues. Design/methodology/approach The aim of this research work is to investigate the change in air permeability values under the incremental extension of cotton tubular weft-knitted fabrics produced from the yarns of different spinning systems. Findings From the results, it is evident that the pique fabric samples of compact spun yarn displayed the highest air permeability values during the incremental stretch at all the three relaxation states. It is followed by the pique samples of ring spun yarn. Next to pique samples, the jersey samples made from the compact yarn and ring spun yarn revealed more air permeability, respectively. The core spun pique samples and core spun jersey samples displayed the least air permeability values, respectively. But, the pique and jersey samples made up of ring yarn and compact yarn showed gradual reduction in their air permeability towards the incremental stretch and the core spun pique samples and core spun jersey samples were uniformly seen with gradual increase in their air permeability during the incremental stretch. Originality/value Very limited quantity of research has been carried out in this area. So, a novel attempt has been made in this research work to investigate the influence of incremental stretch on air permeability of single knit structures.


2016 ◽  
Vol 33 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Piotr Kowalik ◽  
Edyta Wrobel ◽  
Janusz Mazurkiewicz

Purpose – This paper aims to present the results of measurements of the photovoltaic structures made by electroless selective metallization technology. The developed technology provides low-cost contacts in any form, and parameters of photovoltaic cells made in this technology provide reliable results, comparable with those usually used. Design/methodology/approach – In this paper, photovoltaic cells with contacts based on Nip and NiCuP alloy were performed. As a substrate, mono- and multicristaline silicon was used. After photovoltaic cells have been prepared, sheet resistance of the contact layers and electrical parameters were measured. Composition and structure of contact layers were also measured. Findings – Obtained results of sheet resistance and contact layers are repeatable and comparable with previously published results. Electrical parameters of the photovoltaic cells made are comparable with used substrate and technologies. The authors have also noticed that the costs of the electroless metallization which is used to make contact layers is lower than metallization made by thick film or vacuum deposition technologies. Originality/value – The paper presents new, unpublished results of electrical parameters of photovoltaic cells with contact layers made by electroless metallization. The original idea is the usage of metallization in an acidic solution (pH = 2). In this proposed technology, photovoltaic cells on mono- and multicrystalline silicon plates were performed.


Sensor Review ◽  
2017 ◽  
Vol 37 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Krishna Chandra Persaud

Purpose The purpose of this paper is to review recent progress in electronic nose technologies, focusing on hybrid systems combining biological elements with physical transducers. Design/methodology/approach Electronic nose technologies are moving rapidly towards hybrid bioelectronic systems, where biological odour-recognition elements from the olfactory pathways of vertebrates and insects are being utilised to construct new “bionic noses” that can be used in industrial applications. Findings With the increased understanding of how chemical senses and the brain function in biology, an emerging field of “neuromorphic olfaction” has arisen. Research limitations/implications Important components are olfactory receptor proteins and soluble proteins found at the periphery of olfaction called odorant-binding proteins. The idea is that these proteins can be incorporated into transducers and function as biorecognition elements for volatile compounds of interest. Practical implications Major drivers are the security, environmental and medical applications, and the internet of things will be a major factor in implementing low-cost chemical sensing in networked applications for the future. Social implications Widespread take up of new technologies that are cheap will minimise the impact of environmental pollution, increase food safety and may potentially help in non-invasive screening for medical ailments. Originality/value This review brings together diverse threads of research leading to a common theme that will inform a non-expert of recent developments in the field.


2019 ◽  
Vol 31 (3) ◽  
pp. 403-414
Author(s):  
Md Samsu Alam ◽  
Abhijit Majumdar ◽  
Anindya Ghosh

Purpose Bending and shear rigidities of woven fabrics depend on fibre, yarn and fabric-related parameters. However, there is lack of research efforts to understand how bending and shear rigidities change in woven fabrics having similar areal density. The purpose of this paper is to investigate the change in bending and shear rigidities in plain woven fabrics having similar areal density. Design/methodology/approach A total of 18 fabrics were woven (9 each for 100 per cent cotton and 100 per cent polyester) keeping the areal density same. Yarns of 20, 30 and 40 Ne were used in warp and weft wise directions and fabric sett was adjusted to attain the desired areal density. Findings When warp yarns become finer, keeping weft yarns same, bending rigidity remains unchanged but shear rigidity increases in warp wise direction. When weft yarns are made finer, keeping the warp yarns same, both the bending and shear rigidities of fabric increase in warp wise direction. Similar results for fabric bending and shear rigidities were obtained in transpose direction. There is a strong association between fabric shear rigidity and number of interlacement points per unit area of fabric even when fabric areal density is same. Originality/value Very limited research has been reported on the low-stress mechanical properties of woven fabrics having similar areal density. A novel attempt has been made in this research work to investigate the bending and shear rigidities of woven fabrics having similar areal density. Besides, it has been shown that it is possible to design a set of woven fabrics having similar bending rigidity but different shear rigidity.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Crecencia Godfrey Tarmo ◽  
Faisal H. Issa

PurposeGroupthink happens in-group decision-making processes whereby members of a group prematurely arrive at a decision that may indicate consensus but for the aim of protecting group harmony. This limits the contributions of the individuals' talents, ideas, competences and experiences to more effective decisions. Although there are a number of studies on predictors (forecasters) of groupthink, they do not consider the influence of the African cultural aspects of collectivism, high power distance and tolerance on groupthink that may characterise the decision-making context in African settings. It is in that context that this case study analyses groupthink in a public sector organization in Tanzania.Design/methodology/approachThis paper unveils the presence of groupthink predictors that can affect the quality of decisions made in groups within the Tanzania context. The study was conducted in one of the public institutions in Tanzania that is under the Ministry of Home affairs. The study population included Directors, Managers, Heads of units, District registration officers and other officials as shown in Table 1. These are the people who participate in decision-making processes in the organization and were drawn from different offices of the organization including the headquarter office, Kibaha Data centre, District Registration offices from different regions including Dares Salaam, Coast region, Arusha, Mtwara, Mwanza, Manyara, Mbeya, Singida, Dodoma, Geita, Lindi and Njombe – these 12 administrative regions are among the 27 regions that make up the Tanzania mainland. Through simple random and purposive sampling methods, a total of 97 participants participated effectively. The criterion for participation being participants must have been involved with at least one decision-making group experience. The choice of the organization was done on the basis that it is a relatively a new institution of importance; it was also possible to get from it the needed data.FindingsThe results of the study show that there is the presence of groupthink predictors of high trust, conformity and promotional leadership in decision-making groups in the organization. Furthermore, the diversity of group members alone indicates to be insufficient reason to avoid Groupthink. It is suggested that other important factors might be at play in group decision making including the influence of African cultural characteristics.Research limitations/implicationsThis study was limited to only one institution. For a study of this nature to be undertaken access to data could be a very significant problem. Limiting it to one organization we are familiar with made it a bit easy to achieve access.Practical implicationsGroup decision making and groupthink are rarely in discourse in Africa. Tanzania is not isolated from the world, and being a country that unity is a cultural tenet that is promoted at every level from the family to national level (Rwegelera, 2003; Tripp, 1999) effects of groupthink is reasonably conspicuous because of the inbuilt national culture that has shaped people to be tolerant and accepting of different perspectives, ethnic groups, religious and races (Tripp, 1999). The same tolerance and acceptance may be transferred to decision-making groups and easily cause the occurrence of groupthink that can affect the quality of decisions made.Social implicationsThe Tanzania government has dedicated itself to putting strict measures to prohibit unethical and erroneous decisions that cost the nation including reducing employees' misconduct. The findings of this study indicate that there are hidden aspects like groupthink that are not reached by those measures yet ironically impacts the decisions made in organizations and in turn costs organizations and the country at large and calls for the government and its institutions together with the private sector to be awakened and alerted if they are dedicated and concerned about the quality of decisions they make.Originality/valueThis is an original research work building on previous research. Some findings on groupthink and implications have Western origins. In Africa, we need to figure out what is making the continent not to make significant steps to change the social-economic environment. This study highlights to both African academics and leaders with no management background to make them understand groupthink as a phenomena that has implications to quality decisions. It will also prompt similar studies and therefore widen understanding on decisions making.


Cylinder head is one of the main components of an Automobile Engine. In machine shop there are three bays having a machines in which the cylinder head is machined. Makino machine is one of them where the operations like roughing, semi finish; drilling and tapping are carried out. The component has to be loaded by use of a manipulator in a vertical position into the machine such that its rocker face should be facing the operator. So, the component coming from the previous operation through a conveyor with combustion face on top should be tilted to 90 degree such that its rocker face will be facing the operator in a horizontal position. This tilting process has been carried out manually which results in damage of valve guide and valve seat of a cylinder head. This leads to reduction in quality and productivity and also it results in increased operator fatigue since the cylinder head weighs heavy. There is also a chance that when tilting the component manually the component may fall down and hurts operator which results in increased value of effort and ergonomic index. To overcome this problem our research work a modification is made in the conveyor of the makino machine with a low cost automatic arrangement provided for cylinder head tilting purpose


The review article discusses the possibilities of using fractal mathematical analysis to solve scientific and applied problems of modern biology and medicine. The authors show that only such an approach, related to the section of nonlinear mechanics, allows quantifying the chaotic component of the structure and function of living systems, that is a priori important additional information and expands, in particular, the possibilities of diagnostics, differential diagnosis and prediction of the course of physiological and pathological processes. A number of examples demonstrate the specific advantages of using fractal analysis for these purposes. The conclusion can be made that the expanded use of fractal analysis methods in the research work of medical and biological specialists is promising.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guanhua Xun ◽  
Stephan Thomas Lane ◽  
Vassily Andrew Petrov ◽  
Brandon Elliott Pepa ◽  
Huimin Zhao

AbstractThe need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/μL and 1.09 copies/μL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.


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