Srung Smanmoo

Immobilization of fluorescein isothiocyanate on magnetic polymeric nanoparticle using chitosan as spacer

The nanoparticle with simultaneous combination of magnetic and fluorescent properties was prepared by immobilization of fluorescein isothiocyanate (FITC) onto magnetic polymeric nanoparticle (MPNP). The MPNP with 41% magnetic content was obtained from incorporating Fe(3)O(4) magnetic nanoparticles (MNPs) into poly(styrene/divinyl benzene/acrylic acid) via the miniemulsion polymerization. Before labeling with FITC, the carboxylated MPNP was coated with chitosan (CS) having low, medium, or high molecular weight (MW) in order to avoid quenching of the fluorescent by iron oxide. Data obtained from TEM, size and zeta potential measurements clearly indicated the presence of CS as a shell surrounding the superparamagnetic MPNP core. The zeta potential, FTIR, and fluorescent spectroscopies confirmed the attachment of FITC to the MPNP-CS via covalent bonding. The higher MW or longer chains of CS (300kDa) offered the larger spacer with multiple sites for the FITC binding and, thus, provided the higher fluorescent emission intensity. The MPNP-CS immobilized with FITC would be useful for cell-labeling application.

Selective sensing of L-arginine employing luminol dextran conjugate

Abstract

Composite Particles of Disinfectant Nanocapsules-Skim Rubber Latex

Skim latex, a by-product of natural rubber latex, was prevulcanized by sulfur and then used in the preparation of composite particles with disinfectant nanocapsules. Each polymeric nanocapsule contained chlorhexidine digluconate (CHD) as a disinfectant agent encapsulated with poly(methyl acrylate) (PMA) as a shell. The driving force for the heterocoagulation of CHD-PMA nanocapsule and sulfur-prevulcanized skim (SPVS) particle was the electrostatic interaction between the positive charge of lecithin residing on the surface of the nanocapsule and the negative charge from the indigenous surfactant (protein-lipid) and/or from sodium dodecyl sulfate on the surface of the SPVS latex particle. The zeta potential and morphology of heterocoagulated particles indicated the formation of the CHD-PMA/SPVS composite particles. Structures and formation mechanisms of the composite particles with different blend ratios were revealed by depth profiling confocal Raman spectra.

Selective FL Quenching or Enhancing of Diimine Ligands by Guanine

AbstractDiimine ligand (DL) 1 significantly exhibited the fluorescence quenching upon binding to guanine. Changing at the para-substituent of the phenyl ring from the hydroxyl to bromo groups reversely enhanced the fluorescence in the presence of guanine. The reverse in the fluorescence selectivity indicated the profound effect of the substituent at the para-position of the phenyl ring. The simple synthesis of DL 1 and DL 2 with good selectivity for guanine offers these DLs as promising compounds for chemosensors of other guanine derivatives. Figureᅟ