• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.37 no.1
• /
• pp.55-60
• /
• 2011

In this study, DOPC liposomes were prepared with distilled water, phosphate buffer and phosphate buffered saline to evaluate the effects of salt on the stability of DOPC liposome. The changes in physical properties (likeparticle size and zeta potential) of liposome were measured after adding the salt. Liposomes were diluted 40 times and 80 times with hydration solvent to confirm the effect of dilution. Consequently, the stability of liposome was maintained up to 40 times dilution with hydration solvent. The liposome that prepared with distilled water was diluted with distilled water, phosphate buffer and phosphate buffered saline, and the liposome that prepared with phosphate buffer was diluted with phosphate buffer and phosphate buffered saline to evaluate the salt-induced changes in particle size and zeta potentia. As results, the particle size increased slightly and zeta potential became closer to 0 when the salt concentration was increased. In conclusion, particle size and zeta potential of liposome could be reasonable factors to evaluate the stability of liposome. In addition, we suggest that salt concentration of hydration solvent has a significant effect on the stability of liposome.

• Toxicological Research
• /
• v.7 no.2
• /
• pp.183-189
• /
• 1991

Since streptozotocin has been known to be chemically stable only under acidic condition(pH 4), the spontaneous degradation and cellular uptake of streprozotocin in neutral incubation medium was determined by chemical assay. Streptozotocin levels in both phosphate buffered saline (pH 7.4) and Krebs-Henseleit buffer (pH 7.4) decreased with a half life of about 2 hours. The presence of erythrocytes or pepatocytes under the same buffers did not affect the streptozotocin degradation rate at all. However, streptozotocin levels in plasma isolated from rats decreased rapidly compared to those in neutral buffers.

• Korean Journal of Animal Reproduction
• /
• v.19 no.3
• /
• pp.191-195
• /
• 1995

Bovine follicular oocytes were matured in vitro for 3D hr and exposed to Dulbecco's phosphate buffered saline containing 7% ethanol for 7 minutes for their activation, and incubated in TCM199 containing 10% fetal calf serum (FCS) and cytochalasin D (CD). When the oocytes were exposed to cytochalasin D for 0, 5, 10 and 15 hr, 5 hr showed highest developmental rate to blastocyst (16%), expanded blastocyst (13%) and hatched blastocyst (7%). Also when the oocytes were cultured for 7 hours in medium contai ning 0, 2.5, 5 and 7.5 ${\mu}\textrm{g}$/ml cytochalasin D, 2.5 ${\mu}\textrm{g}$/ml showed highest developmental rate to blastocyst (13%), expanded blastocyst (7%) and hatched blastocyst (4%). In conclusion, cytochalasin D played very important role for parthenogenetic development of follicular oocytes and 5 hr of exposure time to CD and 2.5 ${\mu}\textrm{g}$/ml CD in the medium was optimal for development of the follicular oocyte.

• Korean Journal of Veterinary Research
• /
• v.38 no.2
• /
• pp.366-370
• /
• 1998

To determine the efficacy of immunotherapeutic agents, four female Holstein calves 7-day-old were inoculated per os with $1{\times}10^7$ C parvum oocysts (VRI-CN91). Each calf received twice daily oral dosage of 200-500ml of the immune bovine serum, immune bovine colostrum, mAb C6, and phosphate-buffered saline, respectively. Treatment was initiated 4 days postinfection and laster 3 days. The clinical sign of the calf treated with phosphate-buffered saline lasted 9 days after the initial treatment. The calves treated with those immunotherapeutic agents, however, showed decreased severity of diarrhea at day 3, 2, 5 after the initial administration, respectively. The calves treated with immunotherapeutic agents showed reduced parasite loads compared to control calf. These results suggest that oral passive immunotherapy with immune bovine colostrum and immune bovine serum may be a useful treatment approach.

• Applied Chemistry for Engineering
• /
• v.8 no.1
• /
• pp.59-66
• /
• 1997

Di(10-hemisuccinyloxy)decyl muconate(DDM) and di(6-hemisuccinyloxy)hexyl muconate(DHM) were synthesized, and showed a phase transition in an aqueous solution at 97 and $79^{\circ}C$, respectively. They did not form liposomes by themselves or even in the presence of cholesterol or dioleoylphosphatidylethanolamine(DOPE), but did form liposomes when they were mixed with phosphatidylcholine(PC). DHM molecules in liposome membranes were readily polymerized via 1,2-polymerization process on exposure to 254nm. Liposomes composed of DOPE/dioleoylphosphatidylcholine(DOPC)/DHM(3/3/1) were stable at neutral pH, but leaky at weakly acidic pH. The leakage of entrapped calcein from liposomes in phosphate-buffered saline (PBS, $37^{\circ}C$) of pH 4.8 and 5.8 was complete within 30 and 50 min, respectively. The release of toke entrapped calcein was increased with decreasing pH such that 50% and 100% of the calcein were released at pH near 5.5 and 5.0, respectively.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.7 no.3
• /
• pp.161-165
• /
• 2007

In this paper, mesoporous Pt on micro pillars Pt electrode is newly designed, fabricated, and characterized on silicon substrate for non-enzymatic electrochemical sensor micro-chip integrated with CMOS readout circuitry. The fabricated micro/nano Pt electrode has cylindrical hexangular arrayed nano Pt pores with a diameter of 3.2 nm which is formed on top of the micro pillars Pt electrode with approximately $6{\mu}m$ in diameter, $6{\mu}m$ in space, and $50{\mu}m$ in height. The measured current responses of the fabricated plane Pt, mesoporous Pt, and mesoporous Pt on the micro pillar Pt electrodes are approximately $9.9nA/mm^2,\;6.72{\mu}A/mm^2,\;and\;7.67{\mu}A/mm^2$ in 10mM glucose solution with 0.1M phosphate buffered saline (PBS) solution, respectively. In addition, the measured current responses of the fabricated plane Pt, mesoporous Pt, and mesoporous Pt on the micro pillar Pt electrodes are approximately $0.15{\mu}A/mm^2,\;0.56{\mu}A/mm^2,\;and\;0.74{\mu}A/mm^2$ in 0.1mM ascorbic acid (AA) solution with 0.1M phosphate buffered saline (PBS) solution, respectively. This experimental results show that the proposed micro/nano Pt electrode is highly sensitive and promising for CMOS integrated non-enzymatic electrochemical sensor applications. Since the micro-pillar Pt electrode can also be utilized with a micro-fluidic mixer in the sensor chip, the sensor chip can be much smaller, cheaper, and easier to be fabricated.

• Korean Journal of Optics and Photonics
• /
• v.30 no.2
• /
• pp.59-66
• /
• 2019

We report highly sensitive detection of myocardial infarction biomarkers, such as myoglobin and cTnI, within several hundred seconds using a rotating-analyzer ellipsometer and a biosensor with biochips fabricated on a $SiO_2$-coated tilted silicon substrate. We choose the running buffer to be pure phosphate-buffered saline (PBS) or 10% mixed human serum. When we choose the running buffer to be pure PBS, we obtain diagnostic densities of pure myocardial infarction biomarkers of up to 1 ng/ml and 5 pg/ml respectively. Meanwhile, when we use PBS with 10% human serum, the measured densities of myoglobin and cTnI were up to 1 ng/mL and 1 pg/mL respectively. The measured diagnostic densities are less than 1/15 and 1/80 (in cases of myoglobin and cTnI respectively) of those referenced by the World Health Organization.

• Korean Journal of Microbiology
• /
• v.11 no.2
• /
• pp.79-88
• /
• 1973

In order to investigate the effect of gamma radiation on Salmonella typhi, Ty2, the components of amino acids, proteins, carbohydrates and lipids in irradiated cells were compared with those in unirradiated control cells respectively. The results obtained were as follows ; 1) The inactivation curves of Salmonella typhi with $Co^{60}$ .gamma.-ray irradiation were exponential over a wide range to the irradiated doses. 2) Dose for the inactivation factor of $10^8$ was 94.0 Krad in physiological saline or in phosphate buffered saline, 104.2 Krad in nutrient broth, 220.4Krad in frozen state, 552.0 Krad in dried state, 88.3 Krad in the abundance of oxygen and 188.0 Krad in the deficience of oxygen, respectively. 3) Five consecutive irradiation of Salmonella typhi suspension at the dose of 90 Krad gave no additional increase in resistance. 4) Even at the smallest dose of 500 Krad, compositions of amino acids, proteins, carbohydrates, and lipids were more or less decreased and the distinct banding patterns were also lost possibly due to degradation of the protein molecules.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.432.1-432.1
• /
• 2014

Hydroxyapatite (Ca10(PO4)6(OH)2) is known as the main inorganic component of mature mammalian bones and teeth. Because of its biocompatibility, hydroxyapatite has attracted much attention due to its potential applications in many biomedical researches. Here, we tested a therapeutic potential for the use of hydroxyapatite as an anticancer drug delivery vector. We prepared various types of hydroxyapatite having different chemical contents and morphologies using hydrothermal synthesis. The capability of hydroxyapatite as drug delivery materials was examined by adsorption kinetics of 5-fluorouracil molecules, a common anticancer drug, in phosphate buffered saline. We find that hydroxyapatite with smaller crystal size and higher phosphate contents shows improved adsorption property. Given that hydroxyapatite provides a scaffold for bone regeneration, these results highlight a potential use of hydroxyapatite in therapies aimed at osteosarcoma.

• Polymer(Korea)
• /
• v.36 no.3
• /
• pp.357-363
• /
• 2012

Surface-modified poly(L-lactic acid) (PLLA) films and scaffolds were treated with plasma discharge in oxygen gas and subsequently subjected to $in$ $situ$ grafting of acrylic acid (AA) in order to increase the cell compatibility. The surface of AA-grafted PLLA was converted to hydroxyapatite (HA)-deposited PLLA in stimulated body fluid (SBF). After the samples were immersed in phosphate-buffered saline (PBS), fetal bovine serum (FBS), normal saline, or cell medium, the water contact angles were significantly reduced on the surface of HA-deposited PLLA. Chondrocyte and osteoblast showed a higher attachment and cell proliferation on HA-deposited surfaces and in particular, it was confirmed that chondrocyte was considerably influenced by HA. However, osteoblast showed better cell proliferation on the surfaces immersed in FBS, cell medium or HA-deposited surface. In addition, the cell proliferation in 3D scaffolds was much higher than that on film type, irrespective of chondrocyte and osteoblast. Therefore, such surface-modified PLLAs are expected to be useful as organic-inorganic hybrid scaffolds in the regeneration of cartilage and bone.