Mohammadhassan Valadan

Mohammadhassan Valadan
University of Naples Federico II | UNINA · Department of Advanced Biomedical Sciences

Doctor of Philosophy

About

26
Publications
4,039
Reads
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216
Citations
Citations since 2016
21 Research Items
209 Citations
20162017201820192020202120220204060
20162017201820192020202120220204060
20162017201820192020202120220204060
20162017201820192020202120220204060
Additional affiliations
May 2012 - present
Position
  • BioPhysics, Molecular Dynamics, Time-resolved Spectroscopy,
September 2010 - April 2012
Position
  • Physics for Engineers
September 2007 - August 2010
Position
  • Laser Systems

Publications

Publications (26)
Article
The process of surface structuring of a silicon target with femtosecond laser pulses (pulse width ≈180 fs; wavelength λ≈1030 nm) at repetition rates varying from 0.01 to 200 kHz is investigated in vacuum and in air, in static irradiation conditions. The threshold fluence for the formation of a shallow crater, as well as the surface features generat...
Article
Full-text available
The interaction between two-dimensional nanoflakes and bacteria in water-based physiological liquids is a hot topic that unveils new types of phenomena and is fundamental to bioscience applications. In this work, we extend Derjaguin, Landau, Verwey, and Overbeek theory (DLVO theory) that describes the properties of nano-objects in solutions, to the...
Article
Full-text available
Two-dimensional nanomaterials, such as MoS 2 nanosheets, have been attracting increasing attention in cancer diagnosis and treatment, thanks to their peculiar physical and chemical properties. Although the mechanisms which regulate the interaction between these nanomaterials and cells are not yet completely understood, many studies have proved thei...
Article
The electronic energy levels of cyclo(glycine-phenylalanine), cyclo(tryptophan-tyrosine) and cyclo(tryptophan-tryptophan) dipeptides are investigated with a joint experimental and theoretical approach. Experimentally, valence photoelectron spectra in the gas phase are measured using VUV radiation. Theoretically, we first obtain low-energy conformer...
Preprint
Full-text available
The electronic energy levels of cyclo(Glycine-Phenylalanine), cyclo(Tryptophan-Tyrosine) and cyclo(Tryptophan-Tryptophan) dipeptides are investigated with a joint experimental and theoretical approach. Experimentally, valence photoelectron spectra in the gas phase are measured using VUV radiation. Theoretically, we first obtain low-energy conformer...
Article
The electron-cloud phenomenon is one cause of beam instabilities in high intensity positive particle accelerators. Among the proposed techniques to mitigate or control this detrimental effect, micro-/nano-geometrical modifications of vacuum chamber surfaces are promising to reduce the number of emitted secondary electrons. Femtosecond laser surface...
Article
Full-text available
The synthesis of two 5′-end (4-dimethylamino)azobenzene conjugated G-quadruplex forming aptamers, the thrombin binding aptamer (TBA) and the HIV-1 integrase aptamer (T30695), was performed. Their structural behavior was investigated by means of UV, CD, fluorescence spectroscopy, and gel electrophoresis techniques in K+-containing buffers and water-...
Article
Full-text available
Interactions of novel bi-dimensional nanomaterials and live matter such as bacteria and viruses represent an extremely hot topic due to the unique properties of the innovative nanomaterials, capable in some cases to exhibit bactericide and antiviral actions. The interactions between bacteria and viruses and two dimensional nanosheets are here inves...
Article
Full-text available
The identification of molecules whose biological activity can be properly modulated by light is a promising therapeutic approach aimed to improve drug selectivity and efficacy on the molecular target and to limit the side effects compared to traditional drugs. Recently, two photo-switchable diastereomeric benzodiazopyrrole derivatives 1RR and 1RS h...
Article
A novel technique was demonstrated that overcomes important drawbacks to crosslink cells by irradiation with ultrashort ultraviolet laser pulses (L-crosslinking). To use this technique coupled to Chromatin ImmunoPrecipitation (ChIP) in a high throughput context, a prescreening fast method needs to be implemented to set up suitable irradiation condi...
Preprint
A novel technique was demonstrated that overcome important drawbacks to crosslink cells by irradiation with ultrashort UV laser pulses (L-crosslinking). To use this technique coupled to Chromatin ImmunoPrecipitation (ChIP) in a high throughput context, a pre-screening fast method needs to be implemented to set up suitable irradiation conditions of...
Article
Full-text available
We combine Fluorescence Up-Conversion and Time Correlated Single Photon Counting experiments to investigate the 5BenzylUracil excited state dynamics in methanol from 100 fs up to several ns. This molecule has been been proposed as a model for DNA/protein interactions. Our results show emission bands at about 310 and 350 nm that exhibit bi-exponenti...
Article
We analyze surface texturing induced by femtosecond laser irradiation of a silicon target at high repetition rate. The features of the produced surface structures in ablative conditions, i.e. at fluences larger than the ablation threshold, are investigated as a function of number of pulses and pulse energy, for various repetition rates, in the rang...
Article
Full-text available
Two dimensional materials beyond graphene such as MoS2 and WS2 are novel and interesting class of materials whose unique physico-chemical properties can be exploited in applications ranging from leading edge nanoelectronics to the frontiers between biomedicine and biotechnology. To unravel the potential of TMD crystals in biomedicine, control over...
Article
Full-text available
Liquid processing of 2D crystals offers scalable strategies for the production of 2D materials. Herein, we produce the hybrids of MoS2/graphene, consisting of few-layered nanosheets of luminescent MoS2 and biofunctionalized few-layered graphene assisted by the Vmh2 hydrophobin, a self-assembling adhesive fungal protein, through a green route of pro...
Presentation
Full-text available
Highlights: 1. 2DMs based heterostructures 2. Liquid processing of 2DMs 3. Hybrid structures: green route of production 4. Characterization of hybrid systems 5. Conclusions 6. Applications of 2DM derived hybrids
Article
Full-text available
In contrast to the case of pulses in the infrared (IR) and visible range, the temporal characterization of deep-UV femtosecond pulses in combination with their spectral features is still a challenge, essentially due to the lack of suitable nonlinear crystals for second harmonic autocorrelation. Here we report on the characterization of 260 nm, near...
Article
Full-text available
By relying on the Photonic Immobilization Technique of antibodies onto surfaces, we realized portable biosensors for light molecules based on the use of Quartz Crystal Microbalances. Here we compare the quality of the anchoring method when using nanosecond (260 nm, 25 mJ/pulse, 5 ns, 10 Hz rep. rate) and femtosecond (258 nm, 25 J/pulse, 150 fs, 10...
Conference Paper
Full-text available
The realization of a first-order interferometric autocorrelator in a nearly collinear geometry is reported as an alternative method to measure the minimum pulse duration of femtosecond deep-UV laser pulses. The Fourier limited duration of 257-nm femtosecond pulses is measured with high accuracy, and compared to what obtained by spectrally measuring...
Article
The photophysical and photochemical properties of 5-benzyluracil and 5,6-benzyluracil, the latter produced by photocyclization of the former through irradiation with femtosecond UV laser pulses, are investigated both experimentally and theoretically. The absorption spectra of the two molecules are compared and the principal electronic transitions i...
Article
Full-text available
By relying on the photonic immobilization technique of antibodies onto surfaces, we realized portable biosensors for light molecules based on the use of quartz crystal microbalances, given the linear dependence of the method on the laser pulse intensity. Here, we compare the quality of the anchoring method when using nanosecond (260 nm, 25 mJ/pulse...

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Projects

Projects (2)
Project
To investigate the toxic effects of 2D materials and study their scope in biomedical applications such as drug delivery and cancer therapies. To study the bactericidal effects of 2D materials and explore their role in anti-bacterial applications for food preservation and packaging.
Project
Solution processing and biofunctionalization of two-dimensional materials are pivotal for their (biomedical) applications. Here we interface ultrathin layers of MoS2 with the surface active and self-assembling fungal proteins named Vmh2, which belong to the hydrophobin family.