Microviscosity of Supercooled Water Confined within Aminopropyl-modified Mesoporous Silica as Studied by Time-resolved Fluorescence Spectroscopy

Yamaguchi, A.; Namekawa, Manato; Itoh, Tetsuji; Teramae, Norio

doi:10.2116/analsci.28.1065

Cited by 15 publications

(16 citation statements)

References 47 publications

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“…The TMAP-HMM with DNA fragments was fixed on a Teflon holder in a quartz cell (1 cm Â 1 cm) filled with heptane to prevent evaporation of water inside the silica mesopores during the fluorescence measurements 17,19 . The steady-state fluorescence spectra were measured using a spectrofluorophotometer (FP-6500, JASCO) equipped with a cryostat (CoolSpek USP-203, Unisoku).…”

Section: Methodsmentioning

confidence: 99%

“…We believe that the combination of these specific environments, the spatial confinement effect and the high DNA concentration, results in the formation of 3-mer DNA duplexes inside the pore. Further stabilization under supercooled conditions improve the hybridization efficiencies of 3-mer DNA duplexes inside the pore, because the water confined within mesoporous silica can be deeply supercooled [14][15][16][17] .…”

Section: Article Nature Communications | Doi: 101038/ncomms6151mentioning

confidence: 99%

“…Mesoporous silica pores thus provide a potentially useful confined nanospace for stabilizing short nucleotide duplexes. We also employ supercooled confined water [14][15][16][17] as part of our strategy to achieve efficient duplex formation.…”

mentioning

confidence: 99%

“…These T m values imply that duplex formation of short DNA fragments can be accelerated in supercooled water (To273 K), if the solvent water can be deeply and reliably supercooled 19 . It is difficult to control supercooled water in bulk systems; however, water confined inside mesoporous silica can be deeply supercooled and maintains its fluidity at temperatures above 223 K (refs [14][15][16][17]. Silica mesopores, therefore, can be regarded as a novel low-temperature reaction space for accelerating duplex formation of short DNA fragments.…”

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confidence: 99%

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Trinucleotide duplex formation inside a confined nanospace under supercooled conditions

et al. 2014

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Self-assembly of nucleotides of fewer than three base pairs is often found in proteinnucleotide conjugations, despite their energetic instability, and is regarded as the potential starting point for the creation of artificial hydrogen-bonded supramolecular complexes. Here we report duplex formation of 3-mer DNA fragments confined within silica mesopores modified with a positively charged trimethyl aminopropyl monolayer, and their further stabilization under supercooled conditions (To273 K). We load 3-mer DNA fragments with donor-or acceptor-dye into modified silica mesopores and examine their hybridization behaviours using FRET measurements. The FRET results clearly reveal that efficient duplex formation through at least two A-T base pairs can be achieved at 233 K. Enthalpy changes for duplex formation are found to be nearly equal between complementary and single-mismatched 3-mer DNA duplexes. These results confirm confined mesoscale cavities to be a novel low-temperature reaction space for hydrogen-bonded supramolecular complexes.

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Section: Methodsmentioning

confidence: 99%

Section: Article Nature Communications | Doi: 101038/ncomms6151mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Trinucleotide duplex formation inside a confined nanospace under supercooled conditions

et al. 2014

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“…11 The air-dried amine-MSNs (0.2 g) were dispersed in 40 mL of ethanol containing 5 mg of RITC with vigorous stirring for 4 hours at room temperature. The fluorescent-labeled MSNs were washed with ethanol for three times and collected by centrifugation at 6,000 rpm for 5 minutes (Eppendorf).…”

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The spherical nanoparticle-encapsulated chlorhexidine enhances anti-biofilm efficiency through an effective releasing mode and close microbial interactions

Wong

et al. 2016

IJN

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We reported two forms (sphere and wire) of newly fabricated chlorhexidine (CHX)-loaded mesoporous silica nanoparticles (MSNs), and investigated their releasing capacities and anti-biofilm efficiencies. The interactions of the blank MSNs with planktonic oral microorganisms were assessed by field emission scanning electron microscopy. The anti-biofilm effects of the two forms of nanoparticle-encapsulated CHX were examined by 2,3-bis (2-methoxy- 4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide. The profiles of biofilm penetration were analyzed by fluorescent-labeled MSNs using confocal microscopy and ImageJ. The spherical MSNs with an average diameter of 265 nm exhibited a larger surface area and faster CHX-releasing rate than the MSN wires. The field emission scanning electron microscopy images showed that both shaped MSNs enabled to attach and further fuse with the surfaces of testing microbes. Meanwhile, the nanoparticle-encapsulated CHX could enhance the anti-biofilm efficiency with reference to its free form. Notably, the spherical nanoparticle-encapsulated CHX presented with a greater anti-biofilm capacity than the wire nanoparticle-encapsulated CHX, partly due to their difference in physical property. Furthermore, the relatively even distribution and homogeneous dispersion of spherical MSNs observed in confocal images may account for the enhanced penetration of spherical nanoparticle-encapsulated CHX into the microbial biofilms and resultant anti-biofilm effects. These findings reveal that the spherical nanoparticle-encapsulated CHX could preferably enhance its anti-biofilm efficiency through an effective releasing mode and close interactions with microbes.

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RETRACTED: Shrinkable Nanotubes for Duplex Formation of Short Nucleotides

Kameta

Akiyama²

2018

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Molecular monolayer nanotubes produced by self-assembly of an amphiphile modified with a 2-nitrobenzyl group as a photoresponsive unit are able to encapsulate dinucleotides via electrostatic attraction. Upon photoirradiation, the 18 nm inner diameter of the nanotubes shrinks to less than 2 nm as a result of photochemical cleavage of the 2-nitrobenzyl group in the amphiphile. This shrinking of the nanotube channels leads to a propulsive release of the dinucleotides into the bulk solution and simultaneously accelerates formation of the dinucleotide duplexes. The larger nanotube channels without photoirradiation merely release each dinucleotide into the bulk solution, indicating that the squeezing via transportation in the narrow nanotube channels is necessary for duplex formation. In addition to the size effect, water with a lower polarity confined within the narrow nanotube channels helps to stabilize the energetically unfavorable hydrogen-bonded base pair between the dinucleotides. This system should enable researchers to perform biological reactions that occur only in specific environments and conditions in living organisms.

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Microviscosity of Supercooled Water Confined within Aminopropyl-modified Mesoporous Silica as Studied by Time-resolved Fluorescence Spectroscopy

Cited by 15 publications

References 47 publications

Trinucleotide duplex formation inside a confined nanospace under supercooled conditions

Trinucleotide duplex formation inside a confined nanospace under supercooled conditions

The spherical nanoparticle-encapsulated chlorhexidine enhances anti-biofilm efficiency through an effective releasing mode and close microbial interactions

RETRACTED: Shrinkable Nanotubes for Duplex Formation of Short Nucleotides

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