Purification of exopolysaccharide produced from Lactobacillus spp. using ionic-liquid as adjuvant in alcohol/salt-based aqueous two-phase system for its antidiabetic properties

Diabetes is a chronic, metabolic disease characterized by hyperglycemia resulting from either insufficient insulin production or impaired cellular response to insulin. Exopolysaccharides (EPS) produced by Lactobacillus spp. demonstrated promising therapeutic potential in terms of their anti-diabetic properties. Extraction and purification of EPS produced by Lactobacillus acidophilus and Limosilactobacillus reuteri were performed using ethanol precipitation, followed by alcohol/salt based aqueous two-phase system (ATPS). The purification process involved ethanol precipitation followed by an alcohol/salt-based ATPS. The study systematically investigated various purification parameters in ATPS, including ethanol concentration, type and concentration of ionic liquid, type and concentration of salt and pH of salt. Purified EPS contents from L. acidophilus (63.30 μg/mL) and L. reuteri (146.48 μg/mL) were obtained under optimum conditions of ATPS which consisted of 30 % (w/w) ethanol, 25 % (w/w) dipotassium hydrogen phosphate at pH 10 and 2 % (w/w) 1-butyl-3-methylimidazolium octyl sulfate. The extracted EPS content was determined using phenol sulphuric acid method. In α-amylase inhibition tests, the inhibitory rate was found to be 92.52 % (L. reuteri) and 90.64 % (L. acidophilus), while in α-glucosidase inhibition tests, the inhibitory rate was 73.58 % (L. reuteri) and 68.77 % (L. acidophilus), based on the optimized parameters selected in ATPS. These results suggest that the purified EPS derived from the postbiotics of Lactobacillus spp. hold promise as potential antidiabetic agents.

Effects of water immersion on shear bond strength reduction after current application of resin-modified glass-ionomer-cements with and without an ionic liquid

The enhancement in the bonding strength of advanced dental cements has enabled long-lasting dental restorations. However, the high bonding strength can cause difficulty in removing these restorations. Therefore, "smart" dental cements with simultaneous strong bonding and easy on-demand debonding ability are required. A resin-modified glass-ionomer-cement (RMGIC) with an ionic liquid (IL) has demonstrated significant reduction in the bonding strength with current application (CA). This research investigates the effect of immersion in distilled water on the electric conductivity and bonding strength of RMGIC with and without an IL and CA. The RMGIC without the IL exhibited significant electric conductivity after immersion, and a significant decrease in bonding strength with CA. In comparison, the electric conductivity after immersion and the decrease in bonding strength with CA were greater for RMGIC with the IL. Thus, the feasibility of smart dental cements capable of electrically debonding-on-demand is indicated.

Electrical shear bonding strength reduction of resin-modified glass-ionomercement containing ionic-liquid: Concept and validation of a smart dental cement debonding-on-demand

With improvement of bonding strength of recent dental cement, it is difficult nowadays to remove restorations without excessive force or vibration to tooth, occasionally resulting in damage of dentin, enamel, and dental root. Therefore, "smart" dental cement indicating strong bonding and easy debonding-on-demand simultaneously is required. In this research, resin-modified glass-ionomer-cement containing an ionic-liquid, tris(2-hydroxyethyl)methylammonium methylsulfate was produced, and the shear bonding strength before and after direct current application were evaluated. The prototype cement containing 15 to 20 mass% ionic-liquid indicated simultaneously no significant reduction of shear bonding strength from that of the original cement not containing ionic-liquid, and significant reduction of bonding strength to approximately 20% of that of the original cement after direct current application of more than 2 mmC/mm². The prototype cement in this research demonstrated that the concept of smart dental cement electrically debonding-on-demand is feasible.

Determination of the content of alkyl ketene dimer in its latex by an ionic-liquid assisted headspace gas chromatography

This paper reports on an ionic-liquid assisted headspace gas chromatographic (HS-GC) for the determination of the content of alkyl ketene dimer (AKD) in its latex samples, in which the GC system was equipped with a thermal conductivity detector (TCD). The method was based on the AKD hydrolysis conducted in 1-butyl-3-methylimidazolium chloride (ionic-liquid) added medium at 100°C for 10min in a closed headspace sample vial, and the measured CO₂ (the resulting product of the hydrolysis) by HS-GC. The results showed that the present method has a good measurement precision (RSD <2.3%) and accuracy (recoveries from 96 - 105%), and the limit of quantitation (LOQ) is 0.9%. The present method is very suitable to be used for the routine check of AKD content in its latex sample in mill applications. The study also showed that the content of AKD in the tested commercial latex samples were in the range of 3.5-12%.

Facile room temperature deposition of gold nanoparticle-ionic liquid hybrid film on silica substrate

This work presents facile synthesis of gold nanoparticle (Au NP)-ionic liquid hybrid film of <10nm by a simple two-step process at room temperature by deposition of Au NPs suspended in 1-hexyl-1methyl-pyrolidinium bromide, on Si (111) substrates. FTIR results demonstrated that ionic liquid properties remain unaltered during and after Au NP synthesis, and even coating on Si (111) substrate. XRD, XPS, and XAS spectral data confirm the presence of Au(0) while EXAFS data indicated the presence of small particles or incomplete surface species. Cross-sectional analysis using FE-SEM and edge length measurement using AFM showed that the film thickness is ca 10nm.