Improved immobilization of DNA to graphite surfaces, using amino acid modified clays

Ensafi, Ali A.; Heydari‐Bafrooei, Esmaeil; Dinari, Mohammad; Mallakpour, Shadpour

doi:10.1039/c3tb21827a

Cited by 25 publications

(10 citation statements)

References 40 publications

(38 reference statements)

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“…5 For example, the development of DNA immobilization methodologies that strongly stabilize DNA on an electrode surface is thought to be one of the key factors in DNA biosensor design, and the degree of DNA surface coverage is the critical issue in the development of a DNA electrochemical biosensor for rapid detection of DNA interaction and damage by hazardous compounds. 6 The use of the "bottom-up" approach is attractive for the development of controlled DNA architectures on the surface. Unlike widely developed systems based on DNA-origami, 7,8 nanotemplate-driven ordering of DNA molecules does not depend on the specic DNA sequence (and normally does not utilize base pairing of complementary strands), does not require computational design and further synthesis of each molecule included in the structure.…”

Section: Introductionmentioning

confidence: 99%

Nanotemplate-directed DNA segmental thermal motion

2016

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Section: Introductionmentioning

confidence: 99%

Nanotemplate-directed DNA segmental thermal motion

2016

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“…This result is an important step toward controlled DNA immobilization on solid substrates in a “bottom-up” approach, a challenging task in bionanotechnology. Such DNA architectures are essential for biosensors and molecular electronic devices; moreover, directed DNA adsorption onto solid conductive substrates may be used for DNA mapping, precise measurements of conductive and mechanical properties of single DNA molecules. , Graphite is a very appropriate surface for electrochemical studies, such as biosensor applications, due to its low cost, wide potential window, relatively inert electrochemistry, and electrocatalytic activity for a variety of redox reactions. − It is thought that the development of DNA immobilization methodologies that strongly stabilize DNA on the electrode surface is one of the key factors in DNA biosensor design . At the same time, the degree of surface coverage directly influences the sensor response and can be regarded as the critical issue in the development of a DNA electrochemical biosensor for rapid detection of DNA interaction and damage by hazardous compounds .…”

Section: Introductionmentioning

confidence: 99%

Statistical Analysis of Molecular Nanotemplate Driven DNA Adsorption on Graphite

2014

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In this work, we have studied the conformation of DNA molecules aligned on the nanotemplates of octadecylamine, stearyl alcohol, and stearic acid on highly oriented pyrolytic graphite (HOPG). For this purpose, fluctuations of contours of adsorbed biopolymers obtained from atomic force microscopy (AFM) images were analyzed using the wormlike chain model. Moreover, the conformations of adsorbed biopolymer molecules were characterized by the analysis of the scaling exponent ν, which relates the mean squared end-to-end distance and contour length of the polymer. During adsorption on octadecylamine and stearyl alcohol nanotemplates, DNA forms straight segments, which order along crystallographic axes of graphite. In this case, the conformation of DNA molecules can be described using two different length scales. On a large length scale (at contour lengths l > 200-400 nm), aligned DNA molecules have either 2D compact globule or partially relaxed 2D conformation, whereas on a short length scale (at l ≤ 200-400 nm) their conformation is close to that of rigid rods. The latter type of conformation can be also assigned to DNA adsorbed on a stearic acid nanotemplate. The different conformation of DNA molecules observed on the studied monolayers is connected with the different DNA-nanotemplate interactions associated with the nature of the functional group of the alkane derivative in the nanotemplate (amine, alcohol, or acid). The persistence length of λ-DNA adsorbed on octadecylamine nanotemplates is 31 ± 2 nm indicating the loss of DNA rigidity in comparison with its native state. Similar values of the persistence length (34 ± 2 nm) obtained for 24-times shorter DNA molecules adsorbed on an octadecylamine nanotemplate demonstrate that this rigidity change does not depend on biopolymer length. Possible reasons for the reduction of DNA persistence length are discussed in view of the internal DNA structure and DNA-surface interaction.

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“…The bands at 1633.2 and 3434 cm –1 correspond to the H–O–H bending (the water deformation bands) and the hydroxyl stretching vibrations of the interlayer and free-water molecules on the Cloisite 30b nanoclay, respectively. The band at 1033 cm –1 is associated with the stretching vibration of the Si–O and Si–O–Si groups of silicate (siloxane groups), and the band at 913.4 cm –1 is related to the Al–O–Al deformation of aluminate . The spectrum of PGS shows two bands at 1629.7 and 3425.4 cm –1 that correspond to the structural hydroxyl groups and the O–H vibration of physically absorbed water.…”

Section: Resultsmentioning

confidence: 99%

“…The band at 1033 cm −1 is associated with the stretching vibration of the Si−O and Si− O−Si groups of silicate (siloxane groups), and the band at 913.4 cm −1 is related to the Al−O−Al deformation of aluminate. 57 The spectrum of PGS shows two bands at 58 The TEM images of Cloisite 30B, PGS, and acid-treated CNTs are illustrated in Figure 3. As can be seen in Figure 3a, Cloisite 30B has a plate-like structure with a diameter of about 500 nm and uniform size distribution.…”

Section: Resultsmentioning

confidence: 99%

Polyvinylidene Fluoride/Nanoclays (Cloisite 30B and Palygorskite) Mixed Matrix Membranes with Improved Performance and Antifouling Properties

Dehghankar

Mohammadi

Tavakolmoghadam

et al. 2021

Ind. Eng. Chem. Res.

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In this study, it was attempted to prove the effectiveness of nanoclays as economical and nontoxic nanofillers through comparison with carbon nanotubes (CNTs). Two hydrophilic nanoclays, namely, Cloisite 30B and palygorskite (PGS), were used as nanofillers to improve the morphology and performance of polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes. A nonsolvent-induced phase separation (NIPS) method was used to prepare mixed matrix membranes (MMMs). The effects of the nanoclays on morphology, performance, and antifouling properties of the prepared MMMs were investigated. It was found that compared to PVDF membranes, the hydrophilicity, antifouling properties, and morphology of the fabricated MMMs are improved significantly. Compared to PVDF membranes, pure water flux (PWF) values of the MMMs containing the optimum contents of Cloisite 30B (0.5 wt %) and palygorskite (1 wt %) improved by 44.7 and 61.7%, respectively. Acid-treated CNTs were used as a reference additive, and the performance and antifouling properties of the prepared PVDF/nanoclay MMMs were compared with the prepared PVDF/acid-treated CNT MMMs. It was found that the PWF values of the MMM containing optimum contents of PGS and Cloisite 30B nanoclays are 86 and 77%, respectively, compared with that of the MMM containing acid-treated CNTs. The PVDF/Cloisite 30B MMM exhibited lower PWF than the PVDF/PGS MMM, which could be attributed to the plate-like structure of Cloisite 30B. Also, the flux recovery ratio (FRR) values of the mixed matrix membranes containing optimum contents of PGS and Cloisite 30B nanoclays were 95.65 and 92.06%, respectively, compared to that of the MMM containing acid-treated CNTs. Also, the BSA rejections of the prepared MMMs containing optimum contents of Cloisite 30B and palygorskite were comparable with that of the MMM containing acid-treated CNTs. Therefore, nanoclays can be suggested as economical and ecofriendly nanofillers for improving the PVDF membrane performance.

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Improved immobilization of DNA to graphite surfaces, using amino acid modified clays

Abstract: A nano-sized biosensor containing valine amino acid organo-modified Cloisite as a bionanohybrid film for immobilization of DNA was developed.

Cited by 25 publications

References 40 publications

Nanotemplate-directed DNA segmental thermal motion

Nanotemplate-directed DNA segmental thermal motion

Statistical Analysis of Molecular Nanotemplate Driven DNA Adsorption on Graphite

Polyvinylidene Fluoride/Nanoclays (Cloisite 30B and Palygorskite) Mixed Matrix Membranes with Improved Performance and Antifouling Properties

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