Teerasong, Saowapak

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Teerasong, Saowapak
Alternative Name
Teerasong, S.
Main Affiliation
Email
saowapak.te@kmitl.ac.th

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    Item type:Publication,
    Photoregulation of Gold Nanoparticles Stabilized in a Diacetylenic Nanocapsule
    (2017-01-01)
    Somjid, Saowalak
    ;
    Chompoosor, Apiwat
    ;
    Kanokmedhakul, Somdej
    ;
    Teerasong, Saowapak
    The results of releasing a drug in a burst are unpredictable and one of the inherent drawbacks of using nanocarriers. Here, photoresponsive cationic gold nanoparticles to stabilize diacetylenic nanocapsules enabling photoregulated release of payloads are reported. The fabrication of these nanocapsules relied on an electrostatic interaction of a negatively charged diacetylenic core and a positively charged gold nanoparticle shell. Gold nanoparticles with photoresponsive ligands on their surfaces act as both hydrophobic core stabilizers and gatekeepers of the nanocapsules, while their polydiacetylene cores serve as hydrophobic drug carriers that can be tuned using UV irradiation. The morphology of nanocapsules was analyzed using TEM and dynamic light scattering. The resultant nanocapsules had a spherical shape with an average diameter of 152.9 ± 6.7 nm. Upon UV irradiation, the nanocapsules lost their integrity and an encapsulated model compound was released through diffusion. The release of a hydrophobic molecule was irradiation time dependent and thereby controllable. This light-triggered release provides an alternative strategy for controlled drug delivery.
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    Item type:Publication,
    Gold nanorods enhanced resonance Rayleigh scattering for detection of Hg2+ by in-situ mixing with single-stranded DNA
    (2018-02-01)
    Ngernpimai, Sawinee
    ;
    Matulakun, Piyaporn
    ;
    Teerasong, Saowapak
    ;
    Puangmali, Theerapong
    ;
    Kopwitthaya, Atcha
    A resonance Rayleigh scattering (RRS) method for determination of Hg<sup>2+</sup> concentration using positively charged gold nanorods (GNRs) and thymine-rich single-stranded DNA (ssDNA) was developed. Hg<sup>2+</sup> can induce a conformation change of ssDNA from a random coil to a hairpin structure via thymine–Hg<sup>2+</sup>–thymine coordination. Hairpin shaped DNA possesses a high density of negative charges, therefore it caused in a drastic aggregation of GNRs. This resulted in an enhancement of RRS intensity. In this work, a change in RRS intensity proportional to the concentration of Hg<sup>2+</sup> was monitored by spectrofluorometer at excitation and RRS wavelengths of 550 nm (λ<inf>ex</inf> = λ<inf>RRS</inf>). This method offered a detection limit of 0.23 nM, which is lower than the maximum mercury contaminant level specified by the US Environmental Protection Agency. Good precision of analysis was obtained (3.1% relative standard deviation). Furthermore, the method was simple, involving in-situ mixing and sensing in a one-pot solution. Detection was accomplished in 5 min. This makes the method advantageous in terms of convenience and rapidity of analysis. The developed method was successfully applied for detection of Hg<sup>2+</sup> in tap water samples. Recoveries were found in range of 100.6–119.0%.