Fine DNA structure revealed by constant height frequency modulation AFM imaging

Cerreta, Andrea; Vobornik, Dušan; Dietler, Giovanni

doi:10.1016/j.eurpolymj.2013.03.026

Cited by 18 publications

(24 citation statements)

References 38 publications

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“…FM-AFM is a powerful tool for studying the mechanical properties of single biomolecular interactions and force-extension response of isolated molecules in liquid ( Higgins et al, 2005 , Humphris et al, 2000 ). FM-AFM has previously been applied to biological systems to study single polysaccharide molecules ( Humphris et al, 2000 ) and DNA ( Cerreta et al, 2013 ), for example. Gavara and Chadwick (2010) developed the technique further, specifically for applications in the study of the microrheology of biological tissues that produce or detect sound.…”

Section: Introductionmentioning

confidence: 99%

Frequency-modulated atomic force microscopy localises viscoelastic remodelling in the ageing sheep aorta

Akhtar

Graham

Derby

et al. 2016

Journal of the Mechanical Behavior of Biomedical Materials

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Age-related aortic stiffening is associated with cardiovascular diseases such as heart failure. The mechanical functions of the main structural components of the aorta, such as collagen and elastin, are determined in part by their organisation at the micrometer length scale. With age and disease both components undergo aberrant remodelling, hence, there is a need for accurate characterisation of the biomechanical properties at this length scale. In this study we used a frequency-modulated atomic force microscopy (FM-AFM) technique on a model of ageing in female sheep aorta (young: ~18 months, old: >8 years) to measure the micromechanical properties of the medial layer of the ascending aorta. The novelty of our FM-AFM method, operated at 30 kHz, is that it is non-contact and can be performed on a conventional AFM using the ׳cantilever tune’ mode, with a spatial (areal) resolution of around 1.6 μm2. We found significant changes in the elastic and viscoelastic properties within the medial lamellar unit (elastic lamellae and adjacent inter-lamellar space) with age. In particular, there was an increase in elastic modulus (Young; geometric mean (geometric SD)=42.9 (2.26) kPa, Old=113.9 (2.57) kPa, P<0.0001), G′ and G″ (storage and loss modulus respectively) (Young; G′=14.3 (2.26) kPa, Old G′=38.0 (2.57) kPa, P<0.0001; Young; G″=14.5 (2.56) kPa, Old G″=32.8 (2.52) kPa, P<0.0001). The trends observed in the elastic properties with FM-AFM matched those we have previously found using scanning acoustic microscopy (SAM). The utility of the FM-AFM method is that it does not require custom AFM hardware and can be used to simultaneously determine the elastic and viscoelastic behaviour of a biological sample.

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Section: Introductionmentioning

confidence: 99%

Frequency-modulated atomic force microscopy localises viscoelastic remodelling in the ageing sheep aorta

Akhtar

Graham

Derby

et al. 2016

Journal of the Mechanical Behavior of Biomedical Materials

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“…DNA in particular is a polymorphic molecule which structures are strongly affected by the environment [ 6 , 7 ]. Due to the potential exciting applications of DNA electronics [ 8 ], intensified research has been undertaken in the fields of biophysics, chemistry and biomedical research over the past few decades.…”

Section: Introductionmentioning

confidence: 99%

Calculation of the Electronic Parameters of an Al/DNA/p-Si Schottky Barrier Diode Influenced by Alpha Radiation

Al-Ta’ii

Amin

Periasamy

2015

Sensors

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Many types of materials such as inorganic semiconductors have been employed as detectors for nuclear radiation, the importance of which has increased significantly due to recent nuclear catastrophes. Despite the many advantages of this type of materials, the ability to measure direct cellular or biological responses to radiation might improve detector sensitivity. In this context, semiconducting organic materials such as deoxyribonucleic acid or DNA have been studied in recent years. This was established by studying the varying electronic properties of DNA-metal or semiconductor junctions when exposed to radiation. In this work, we investigated the electronics of aluminium (Al)/DNA/silicon (Si) rectifying junctions using their current-voltage (I-V) characteristics when exposed to alpha radiation. Diode parameters such as ideality factor, barrier height and series resistance were determined for different irradiation times. The observed results show significant changes with exposure time or total dosage received. An increased deviation from ideal diode conditions (7.2 to 18.0) was observed when they were bombarded with alpha particles for up to 40 min. Using the conventional technique, barrier height values were observed to generally increase after 2, 6, 10, 20 and 30 min of radiation. The same trend was seen in the values of the series resistance (0.5889–1.423 Ω for 2–8 min). These changes in the electronic properties of the DNA/Si junctions could therefore be utilized in the construction of sensitive alpha particle detectors.

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“…Structures of DNA are strongly influenced by the environmental conditions due to their polymorphic nature 21 22 , which may be utilized in various exciting applications 23 . In industry, the utilization of metal-oxide semiconductors 24 , conventional semiconductors 25 26 and organic semiconductors 27 28 have led to fabrication of high-speed Schottky diodes.…”

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confidence: 99%

Humidity influenced capacitance and resistance of an Al/DNA/Al Schottky diode irradiated by alpha particles

Al-Ta’ii

Amin

Periasamy

2016

Sci Rep

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Deoxyribonucleic acid or DNA based sensors, especially as humidity and alpha particle sensors have become quite popular in recent times due to flexible and highly optimizable nature of this fundamental biomaterial. Application of DNA electronics allow for more sensitive, accurate and effective sensors to be developed and fabricated. In this work, we examined the effect of different humidity conditions on the capacitive and resistive response of Aluminum (Al)/DNA/Al Schottky barrier structure when bombarded by time-dependent dosages of alpha particles. Based on current-voltage profiles, which demonstrated rectifying behaviours, Schottky diode parameters such as ideality factor, barrier height and series resistance was calculated. Results observed generally pointed towards a decrease in the resistance value from the pristine to the radiated structures. It was also demonstrated that under the effect of humidity, the capacitance of the DNA thin film increased from 0.05894 to 92.736 nF, with rising relative humidity level. We also observed the occurrence of the hypersensitivity phenomena after alpha irradiation between 2 to 4 min by observing a drop in the series resistance, crucial in the study of DNA damage and repair mechanisms. These observations may also suggest the exciting possibility of utilizing Al/DNA/Al Schottky diodes as potentially sensitive humidity sensors.

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Fine DNA structure revealed by constant height frequency modulation AFM imaging

Cited by 18 publications

References 38 publications

Frequency-modulated atomic force microscopy localises viscoelastic remodelling in the ageing sheep aorta

Frequency-modulated atomic force microscopy localises viscoelastic remodelling in the ageing sheep aorta

Calculation of the Electronic Parameters of an Al/DNA/p-Si Schottky Barrier Diode Influenced by Alpha Radiation

Humidity influenced capacitance and resistance of an Al/DNA/Al Schottky diode irradiated by alpha particles

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