Modifications in solvent clusters embedded along the fibers of a cellulose polymer network cause paper degradation

Spirito, Marco De; Missori, Mauro; Papi, Massimiliano; Maulucci, Giuseppe; Teixeira, J.; Castellano, Carlo; Arcòvito, Giuseppe

doi:10.1103/physreve.77.041801

Cited by 28 publications

(38 citation statements)

References 26 publications

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“…The usable range, where data are reliable, was found to be 0.2-3. A paper sample consists of a random assembly of cellulose fibers and voids and their relative amount is sample dependent [1,4]. In order to assess the volume fraction v of cellulose fibers in the samples and recover their absolute THz absorption coefficient, the density (ρ paper ) of each paper sample was measured.…”

Section: Methodsmentioning

confidence: 99%

Terahertz Absorption by Cellulose: Application to Ancient Paper Artifacts

et al. 2017

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Artifacts made of cellulose, such as ancient documents, pose a significant experimental challenge in the THz transmission spectra interpretation due to their small optical thickness. In this Letter we describe a method to recover the complex refractive index of cellulose fibers from the THz transmission data obtained on single freely standing paper sheets in the 0.2-3.5 THz range. By using our technique, we were able to eliminate Fabry-Perot effects and recover the absorption coefficient of the cellulose fibers. The obtained THz absorption spectra are explained in terms of absorption peaks of the cellulose crystalline phase superimposed to a background contribution due to a disordered hydrogen bonds network. The comparison between the experimental spectra with THz vibrational properties simulated by density functional theory calculations confirms this interpretation. In addition, evident changes in the THz absorption spectra are produced by natural and artificial aging on paper samples, whose final stage is characterized by a spectral profile with only two peaks at about 2.1 THz and 3.1 THz. These results could be used to provide a quantitative assessment of the state of preservation of cellulose artifacts.

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Section: Methodsmentioning

confidence: 99%

Terahertz Absorption by Cellulose: Application to Ancient Paper Artifacts

et al. 2017

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“…Furthermore, this system could be particularly important as a scaffold for the growth of controlled networks of biological molecules [36][37][38].…”

Section: Resultsmentioning

confidence: 99%

Controlling the Cassie-to-Wenzel Transition: an Easy Route towards the Realization of Tridimensional Arrays of Biological Objects

et al. 2014

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Abstract:In this paper we provide evidence that the Cassie-to-Wenzel transition, despite its detrimental effects on the wetting properties of superhydrophobic surfaces, can be exploited as an effective micro-fabrication strategy to obtain highly ordered arrays of biological objects. To this purpose we fabricated a patterned surface wetted in the Cassie state, where we deposited a droplet containing genomic DNA. We observed that, when the droplet wets the surface in the Cassie state, an array of DNA filaments pinned on the top edges between pillars is formed. Conversely, when the Cassie-to-Wenzel transition occurs, DNA can be pinned at different height between pillars. These results open the way to the realization of tridimensional arrays of biological objects.

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“…We also demonstrated the effect of a long and continuous treatment with the agonist on the same parameters. AFM indeed allows for the detection of dynamic changes in the mechanical properties of living cell surface [26], [27], as well as measurements in air or fluid of unstained and uncoated biological samples in controlled environments and in a nanoscale resolution [28]–[31], without the requirement of any special treatment that can result in cell destruction or alteration. Moreover, single molecule force spectroscopy offers a unique opportunity to detect molecular recognition between individual ligands and receptors.…”

Section: Introductionmentioning

confidence: 99%

Leuprorelin Acetate Long-Lasting Effects on GnRH Receptors of Prostate Cancer Cells: An Atomic Force Microscopy Study of Agonist/Receptor Interaction

et al. 2013

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High cell-surface GnRH receptor (GnRH-R) levels have been shown to have a major influence on the extent of GnRH agonist-mediated tumor growth inhibition. The ability of the GnRH agonist leuprorelin acetate (LA) to induce a post-transcriptional upregulation of GnRH-R at the plasma membrane of androgen-sensitive (LNCaP) and -insensitive (PC-3) prostate cancer (PCa) cells has been previously demonstrated by Western blotting. Here we performed single molecule force spectroscopy by using Atomic Force Microscopy (AFM), which has proven to be a powerful tool allowing for investigation of living cell surface biological features, such as the so far unclear GnRH agonist/receptor interaction. Thus, in the hormone-insensitive PC-3 cells, we characterized the strength of the LA-receptor binding, and the amount and distribution of the functional receptor molecules on the cell surface. The effect of a long and continuous treatment (up to 30 days) with the agonist (10−11 and 10−6 M) on the same parameters was also investigated. A GnRH-R increase was observed, reaching the maximum (∼80%) after 30 days of treatment with the highest dose of LA (10−6 M). The analogue-induced increase in GnRH-R was also demonstrated by Western blotting. In addition, two different receptor bound strengths were detected by AFM, which suggests the existence of two GnRH-R classes. A homogeneous distribution of the unbinding events has been found on untreated and treated PC-3 cell surfaces. The persistence of high receptor levels at the membrane of these living cells may warrant the maintenance of the response to LA also in androgen-unresponsive PCa. Moreover, the determination of ligand/receptor bond strength could shed light on the poorly understood event of LA/GnRH-R interaction and/or address structural/chemical agonist optimizations.

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Modifications in solvent clusters embedded along the fibers of a cellulose polymer network cause paper degradation

Cited by 28 publications

References 26 publications

Terahertz Absorption by Cellulose: Application to Ancient Paper Artifacts

Terahertz Absorption by Cellulose: Application to Ancient Paper Artifacts

Controlling the Cassie-to-Wenzel Transition: an Easy Route towards the Realization of Tridimensional Arrays of Biological Objects

Leuprorelin Acetate Long-Lasting Effects on GnRH Receptors of Prostate Cancer Cells: An Atomic Force Microscopy Study of Agonist/Receptor Interaction

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