A micro hydro-gel is a submicron- or micron-sized network polymer particle that is insoluble in water but highly swellable. This review presents the following topics: preparation, properties, and applications of micro hydrogels. First, two types of preparation methods for micro hydrogels are presented: (i) particle-forming polymerization and (ii) molecular assembly of polymer chains dissolved in water. Next, the characteristic properties of micro hydrogels are discussed. Finally, the applications of micro hydrogels are reviewed, with special emphasis on environmentally sensitive optical/photonic, biological/biomedical, and chemical applications. This review is not comprehensive, but is rather a “mini-review” primarily focused on results obtained in the author’s laboratories.
Accumulation of phospholipid hydroperoxide (PLOOH) in erythrocyte membranes is an abnormality found in patients with senile dementia, including those with Alzheimer’s disease. In our previous studies, dietary xanthophylls (polar carotenoids such as lutein) were hypothesized to inhibit lipid peroxidation. In the present study, we conducted a randomized, double-blind, placebo-controlled human trial to assess the impact for a total of 2 months Chlorella supplementation (8 g Chlorella/day/person; equivalent to 22.9 mg lutein/day/person) on PLOOH and carotenoid concentrations in erythrocytes as well as plasma of 12 normal senior subjects. After 1 or 2 months of treatment, erythrocytes and plasma lutein concentrations increased in the Chlorella group but not in the placebo group. In the Chlorella-supplemented group, erythrocyte PLOOH concentrations after a total of 2 months of treatment were lower than the concentrations before supplementation. These results suggest that Chlorella ingestion improved erythrocyte antioxidant status and lowered PLOOH concentrations. These reductions might contribute to maintaining the normal function of erythrocytes and prevent the development of senile dementia.
This study investigated the short-term effects of the triglyceride (TG), free fatty acid (FFA), ethyl ester (EE), and phospholipid (PL) forms of docosahexaenoic acid (DHA) on the absorption of omega-3 fatty acids (FA) into tissues. Male Balb/c mice were fed a low-fat (LF, 5%) or high-fat (HF, 22.5%) diet containing different formulations of 0.7% omega-3 fatty acid for 1 week. The fatty acid compositions of the liver, adipose tissue, gastrocnemius muscle, and brain were determined. After 1 week, TG-, FFA-, and PL-DHA increased the concentration of DHA in the livers of mice fed LF diet. The hepatic DHA concentration also increased significantly in the HF-TG and HF-PL groups (39.7% and 45.0%, respectively; p < 0.05). In adipose tissue, the DHA levels in mice fed LF-DHA diets were all elevated; the same trend was observed in the HF-DHA diet groups. The proportion of DHA in the gastrocnemius muscle in the LF-DHA diet groups was higher than that in the LF-control group, but no marked increase was observed in the HF-DHA diet groups. In the gastrocnemius muscle, all DHA forms significantly increased the DHA content in mice fed an LF diet; in mice fed an HF diet, EE-DHA and PL-DHA significantly increased the concentration of DHA. No significant changes were observed in the cerebral DHA content when the various forms of DHA were added to the LF diet. However, FFA-, EE-, and PL-DHA increased the cerebral concentration of DHA significantly when added to an HF diet. The present study suggests that the molecular form of DHA contributes to the effects of omega-3 polyunsaturated fatty acids on lipid metabolism. DHA-PL and DHA-TG were more efficient than other DHA forms in increasing the omega-3 concentration in mouse organs.
Chicken fat and sunflower oil 2:3 m/m blend was enzymatically interesterified at 60°C with and without microwaves assistance. As the catalyst a commercial preparation of the immobilized lipase from Rhizomucor miehei (Lipozyme RM IM) containing 2% of water was used, and the catalyst load was 8% in each case. The starting mixture and the interesterified products were separated by column chromatography into pure triacylglycerols fraction (TAG) and a non-triacylglycerol fraction, which contained free fatty acids (FFA), mono- and diacylglycerols (MAG and DAG). The oxidative stabilities (OS) of fats studied and TAG derived from them were assessed by Rancimat at 100°C and by Pressure Differential Scanning Calorimetry (PDSC) under oxygen at 110-140°C. Interesterification reduced the OS of chicken fat and sunflower oil blend. The main factors influenced on the OS of fats studied were concentrations of tocopherols and presence of FFA, MAG- and DAG. The structures of TAGs were of minor importance. From the resulting PDSC exotherms their times to reach the onset (τon) and peak maximum (τmax) were measured and used for calculations of parameters of the Arrhenius type kinetics for thermaloxidative decomposition of fats studied.
Fatty acid amides were prepared by using Lewis acid as a catalyst. The products from reaction was subjected to solvent extraction with chloroform and then followed by purification with n-hexane, ethanol and acetonitrile. Fatty acid amide, characterized by various physicochemical and tribological properties like wear scar, weld load and coefficient of friction. These compounds found good antiwear (AW) and extreme pressure (EP) additive. The addition of various EP and AW additives in lubricating oil is an important and effective way to reduce friction and wear. Fatty acid amides were used as antiwear and friction modifier additive and a comparative study was carried out for 1%, 3%, 5% additive blend with commercial petroleum base stocks 150N and 500N.
The solution properties of a typical gemini surfactant of decanediyl-1-10-bis (dimethyltetradecylammonium bromide) (abbrev. 14-10-14,2Br–) were examined in an aqueous medium at temperatures of 288.2, 298.2, and 308.2 K. The characterization was performed by employing surface tension measurements, electrical conductivity measurements, steady-state fluorescence quenching (SSFQ), and dynamic light scattering (DLS). The surface tension was measured with the drop volume method, in which an improved tensiometer was used and the experimental operation was modified. The resultant data were well reproducible and the equilibrium adsorption time after producing the droplet onto the tip of the capillary was on the order of minutes. In addition, the critical micelle concentration obtained from the surface tension data is in good agreement with that obtained from the conductivity data. Using the conductivity variation as a function of surfactant concentration, the thermodynamic parameters of micellization were calculated. Furthermore, the SSFQ method suggests a small and constant aggregation number, irrespective of temperature. The formation of small-size micelles was also confirmed by DLS measurements.
We investigated the location of cholesterol (Chol) in liposomes and its interaction with phospholipids using small-angle x-ray scattering (SAXS) data and applying the generalized indirect Fourier transformation (GIFT) method. The GIFT method has been applied to lamellar liquid crystal systems and it gives quantitative data on bilayer thickness, electron density profile, and membrane flexibility (Caillé parameter). When the GIFT method is applied to the SAXS data of dipalmitoylphosphatidylcholine (DPPC) alone (Chol [–]) or a DPPC/Chol = 7/3 mixed system (Chol [+], molar ratio), change in the bilayer thickness was insignificant in both systems. However, the electron density for the Chol (+) system was higher than that for the Chol (–) system at the location of hydrophilic groups of phospholipids, and whereas Caillé parameter value increased with temperature for the Chol (–) system, no significant change with temperature was observed in the Caillé parameter for the Chol (+) system. These results indicated that Chol is located in the vicinity of the hydrophilic group of the phospholipids and constricts the packing of the acyl chain of phospholipids in the bilayer.
In order to study the effect of metal ions on lipase activity, hydrolytic and transesterification activities of Candida rugosa lipase were investigated in presence of alkali (Na+ and K+), alkaline earth (Ca+2 and Ba+2) and transition (Cr+3, Fe+3, Co+2, Cu+2 and Ni+2) metal ions. Maximum enhancement in hydrolytic activity of lipase was observed by Ca+2, and in transesterification activity by Cr+3 and Co+2. The kinetics of the lipase catalyzed transesterification (methanolysis and ethanolysis) reactions were also studied, and the activation energies of methanolysis and ethanolysis were reduced from 10.16 and 10.24 kcal mol–1, respectively, to 5.41 and 7.55 kcal mol–1, respectively, when reactions were performed in presence of Co+2. Thus, in lipase catalyzed transesterification Cr+3 or Co+2 could be added to the assay in order to produce the biodiesel in relatively shorter reaction duration.
Various fatty acids are attracting considerable interest for their anticancer effects. Among them, fatty acids containing conjugated double bonds show one of the most potent cytotoxic effects on cancer cells. Here, we focused on the cancer cell killing activity of jacaranda seed oil. The seed oil of jacaranda harvested from Miyazaki in Japan contained 30.9% cis-8, trans-10, cis-12 octadecatrienoic acid, called jacaric acid (JA). Fatty acid prepared from this oil (JFA) and JA strongly induced cell death in human leukemia HL-60 cells. On the other hand, linoleic acid and trans-10, cis-12 conjugated linoleic acid (<10 μM) did not affect cell proliferation and viability. An increase in the sub-G1 population and internucleosomal fragmentation of DNA was observed in JA- and JFA-treated cells, indicating induction of apoptotic cell death. Finally, the cytotoxic effects of JA and JFA were completely abolished by α-tocopherol. Taken together, these data suggest that jacaranda seed oil has potent apoptotic activity in HL-60 cells through induction of oxidative stress.
Stroke-prone spontaneously hypertensive rats (SHRSP) are utilized as models for study of the pathogenesis of not only stroke and cardiovascular disorders but also atherosclerosis and metabolic syndrome. Basic information on the profiles of fatty acids and lipid classes in the liver is indispensable to use SHRSP as a model of disorder of lipid metabolism; nevertheless, detailed information on the metabolism of triacylglycerols (TAGs) and fatty acids in the liver of SHRSP is lacking. This study aimed to characterize profiles of lipid classes and fatty acids and to explore the mechanism underlying the characteristic alterations in metabolism of TAGs and fatty acids in the liver of SHRSP, in comparison with spontaneously hypertensive rats (SHR). The characteristic changes observed in SHRSP were (1) markedly lower hepatic TAG contents; (2) altered expressions of genes encoding three enzymes responsible for the control of TAG level, namely, adipose triglyceride lipase (for TAG degradation; up-regulated), carnitine palmitoyltransferase 1a (for fatty acid β-oxidation; up-regulated) and long-chain acyl-CoA synthetase 3 (for glycerolipid synthesis; down-regulated); (3) evidently lower contents and proportions of monounsaturated fatty acids, in particular cis-vaccenic acid (18:1n-7), in the liver and serum; and (4) down-regulation of palmitoleoyl-CoA chain elongase, which is necessary for the biosynthesis of 18:1n-7, in the liver. From the above observations, we concluded that there are significant differences in profiles of lipid classes and fatty acids between SHRSP and SHR, and that altered characteristics in SHRSP are likely responsible for increases in TAG hydrolysis and β-oxidation, and decreases in TAG synthesis and 18:1n-7 synthesis.
In this study, raw wheat bran (R-WB), a type of waste biomass (WB) was treated with Pectinase PL (P-WB), and the properties (yield percentage, carboxy group surface concentration, the solution pH, and specific surface area) of R-WB and P-WB were investigated. The surface concentration of carboxy groups on R-WB (3.56 mmol/g) was greater than that of P-WB (2.11 mmol/g). In contrast, the specific surface area of P-WB (24.98 m2/g) was greater than that of R-WB (3.25 m2/g). In addition, the adsorption of cadmium and lead ions to WB was evaluated. Adsorption of the heavy-metal ions reached equilibrium within 9 h, and the experimental data was fitted to a pseudo-second-order model. More heavy-metal ions were adsorbed onto R-WB than onto P-WB. The correlation coefficient between the amount of ions adsorbed and the number of carboxy groups or pectin exceeded 0.884 and 0.975, respectively. This study indicated that wheat bran was useful for the removal of cadmium or lead ions from aqueous solutions. The adsorption mechanism of cadmium and lead ions to WB was associated with presence of carboxy group in pectin.
We succeeded in purifying the carotenoid produced by Bacillus firmus GB1 using chromatography on polystyrenic synthetic adsorbents, and identified it as 4,4’-diapolycopene-4,4’-dioic acid by HRESI-MS and NMR analyses of it and its dimethylester. In addition, we clarified the singlet oxygen (1O2) quenching activities of 4,4’-diapolycopene-4,4’-dioic acid and its methyl esters (mono and dimethyl ester). Their IC50 values were 5.8 μM, 6.0 μM, and 6.2 μM, respectively. To our knowledge, this is the first report concerning the isolation and antioxidative activity of 4,4’-diapolycopene-4,4’-dioic acid, a product of the C30 carotenoid biosynthesis pathway.
The aim of this study was to investigate the toxic impacts of titanium dioxide nanoparticles (TiO2-NPs) on rat kidneys and the possible prophylactic role of either quercetin or idebenone. TiO2-NPs were administered orally at either 600 mg or 1 g/kg body weight for 5 consecutive days to evaluate dose-dependent toxicity referred to the OECD guidelines for testing of chemicals. The results showed that administration of either low or high repeated doses of TiO2-NPs to rats significantly increases serum kideney function biomarkers (urea, creatinine and uric acid) as well as increases in serum glucose and serum immuno- inflammatory biomarkers including tumor necrosis factor- α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), immunoglobin g (IGg), vascular endothelial growth factor (VEGF, angiogenic factor) and nitric oxide (NO) with a concomitant decrease in renal GSH content versus normal control values. The increase in these biomarkers was more evident in rats intoxicated with high TiO2-NPs repeated doses. Oral co- administration of either quercetin or idebenone (each 200mg/Kg body weight) daily for three weeks to rats intoxicated by either of the two doses markedly ameliorated TiO2-NPs induced alteration in the above biomarkers. The prophylactic impacts of both agents on biochemical markers were more pronounced in rats received low TiO2-NPs repeated doses. The biochemical investigation was supported by histological examination. In conclusion, The data showed the severity in renotoxicity of TiO2-NPs was dose-dependent and the protective effect of quercetin and idebenone may be related to their antioxidant and anti-inflammatory properties.