Enterococcus sp. JA-27에 의한 가용성 전분으로부터 L형 젖산의 생산

김경아 ( Kim Gyeong A ),김미경 ( Kim Mi Gyeong ),장경린 ( Jang Gyeong Lin ),전홍기 ( Jeon Hong Gi ) 부산대학교 김치연구소 2003 김치의 과학과 기술 Vol.9 No.-

Synthesis and Characterization of Poly(ester amide)s Consisting of Poly(L-lactic acid) and Poly(butylene succinate) Segments with 2,2'-Bis(2-oxazoline) Chain Extending

Jun Zou,Yingzhen Qi,Lele Su,Yun Wei,Zhaolei Li,Haiqing Xu 한국고분자학회 2018 Macromolecular Research Vol.26 No.13

An aliphatic polyester based poly(ester amide)s (PEA) consisting of poly (L-lactic acid) and poly(butylene succinate) was successfully prepared via chain extension reaction of poly(L-lactic acid)-dicarboxylic acid (PLLA-COOH) and poly(butylene succinate)-dicarboxylic acid (PBS-COOH) using 2,2'-bis(2-oxazoline) as a chain extender. PLLA-COOH was obtained by direct polycondensation of L-lactic acid in the presence of 1, 4-succinic acid. PBS-COOH was synthesized by condensation polymerization of 1,4-butylene glycol with excessive succinic acid. The structures of PLLA-COOH, PBS-COOH, and PEAs were characterized by fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (1H NMR). The molar masses were determined by gel permeation chromatography (GPC). The thermal properties of PLLACOOH, PBS-COOH, and PEAs were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The lattice parameters of PLLACOOH, PBS-COOH, and PEAs were investigated by X-ray diffraction (XRD). Furthermore, The mechanical properties were characterized by tensile testing and notch Izod impact testing. The FTIR and 1H NMR results demonstrated the formation of PLLA-COOH, PBS-COOH, and PEAs. The GPC measurements showed that the molar masses of copolymer PEAs decreased with increasing PBS-COOH content. The TGA analysis confirmed that the introduction of PBS improved the thermal properties. DSC data indicated that the melting temperatures of the PEAs were lower than that of the prepolymers. The results of XRD suggested that the PLLA crystal structures was destroyed by the PBS units, and the crystallization of the PEAs mainly attributed to the PBS chain segments.The introduction of PBS units into the polymer structure improved the toughness of PLLA, which was detected in mechanical properties.

Poly(D-lactic acid-b-L-lactic acid)의 결정화거동 및 열적 특성

이경우,박흥수,김영호,Lee, Kyoung-Woo,Park, Heung-Su,Kim, Young-Ho 한국섬유공학회 2010 한국섬유공학회지 Vol.47 No.6

A stereocomplex of poly(lactic acid) (PLA) from the opposite enantiomeric configurations of the L and D forms has higher thermal resistance and mechanical properties than poly(L-lactic acid) (PLLA), which may overcome the problems with the low melting temperature of PLLA when used as a commercial fiber. In this study, the crystallization behavior and thermal properties of poly(D-lactic acid-b-L-lactic acid) (PDLLA) block copolymer (50:50, w/w) were characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis, and wide angle X-ray diffraction (WAXD) analysis. DSC showed that the melting temperature of the stereocomplex crystal was approximately $215^{\circ}C$, which was much higher than that of homo PLLA (${\sim}168^{\circ}C$). The equilibrium melting temperature and stability parameter of PDLLA obtained from the Hoffman-Weeks plot was $230^{\circ}C$ and 0.44, respectively. Compared to the WAXD peaks of the ${\alpha}$-form crystal of PLLA, additional peaks were observed for PDLLA at $11.9^{\circ}$, $20.8^{\circ}$, and $23.6^{\circ}$ $2{\theta}$ arising from the D,L-stereocomplex crystal of PLA. The crystallization behaviors of PDLLA and PLLA during the heating and cooling processes from the melt-quenched state and from the molten state, respectively, were compared using the WAXD curves obtained from a synchrotron X-ray source. The effects of annealing of both PLLA and PDLLA films at different temperatures on the crystal formation were also examined.

Poly(L-lactic acid-block-γ-aminobutyric acid)의 합성과 특성

김자원,김홍성,Kim, Ja Won,Kim, Hong Sung The Korean Fiber Society 2015 한국섬유공학회지 Vol.52 No.1

Biodegradable block copolymer of poly(L-lactic acid-block-${\gamma}$-aminobutyric acid) were synthesized for the controlled release of ${\gamma}$-aminobutyric acid (GABA), a neurotransmitter. Poly(L-lactic acid-block-${\gamma}$-aminobutyric acid) was prepared by the self-initiative polymerization of 2-pyrrolidone at the activated end group of poly(L-lactic acid), which was substituted with dehydrated 2-pyrrolidone. The molecular structure of the block copolymer was analyzed by FT-IR spectroscopy, 1H NMR spectroscopy, and XRD. The surface energies and biodegradabilities of the block copolymers were tested. The release behavior of GABA from the block copolymer matrices was investigated. The relative quantity of the blocks had an accommodative amplitude in the release of GABA.

Synthesis and Micellar Characterization of CBABC Type PLGA-PEO-PPO-PEO-PLGA Pentablock Copolymers

Haseob Seong,조은범,Joongseok Oh,장태현 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.8

Poly(lactic-co-glycolic acid) (PLGA) were grafted to both ends of Pluronic® F68 ((EO)75(PO)30(EO)75) triblock copolymer to produce poly{(lactic acid)m-co-(glycolic acid)n}-b-poly(ethylene oxide)75-b-poly(propylene oxide)30-b-poly(ethylene oxide)75-b-poly{(lactic acid)m-co-(glycolic acid)n} (PLGA-F68-PLGA) pentablock copolymers. Molecular weights of PLGA blocks were controlled and five kinds of pentablock copolymers with different PLGA block lengths were synthesized using in-situ ring-opening polymerization of D,L-lactide and glycolide with tin(II) 2-ethylhexanoate (Sn(Oct)2) catalyst. PLGA-F68-PLGA pentablock copolymers were characterized by ¹H- and ¹³C-NMR, GPC, and TGA. The numbers (2m, 2n) of repeating units for lactic acid and glycolic acid inside PLGA segments were obtained as (48, 17), (90, 23), (125, 40), (180, 59), and (246, 64), with 1H-NMR measurement. From NMR data, the resultant molecular weights were determined in the range of 12,700-29,700, which were similar to those obtained from GPC. Polydispersity index was increased in the range of 1.32-1.91 as the content of PLGA blocks increased. TG and DTG thermograms showed discrete degradation traces for PLGA and F68 blocks, which indicate the weight fractions of PLGA blocks in pentablock copolymers can be calculated by TG profile and it is possible to remove PLGA block selectively. Hydrodynamic radius and radius of gyration of pentablock copolymer micelle were obtained in the range of 46-68 nm and 31-49 nm, respectively, in very dilute (i.e. 0.005 wt %) aqueous solution of THF:H2O = 10:90 by volume at 25 oC.

Synthesis and Micellar Characterization of CBABC Type PLGA-PEO-PPO-PEO-PLGA Pentablock Copolymers

Seong, Haseob,Cho, Eun-Bum,Oh, Joongseok,Chang, Taihyun Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.8

Poly(lactic-co-glycolic acid) (PLGA) were grafted to both ends of Pluronic$^{(R)}$ F68 ($(EO)_{75}(PO)_{30}(EO)_{75}$) triblock copolymer to produce poly{(lactic acid)$_m$-co-(glycolic acid)$_n$}-b-poly(ethylene oxide)$_{75}$-b-poly(propylene oxide)$_{30}$-b-poly(ethylene oxide)$_{75}$-b-poly{(lactic acid)$_m$-co-(glycolic acid)$_n$} (PLGA-F68-PLGA) pentablock copolymers. Molecular weights of PLGA blocks were controlled and five kinds of pentablock copolymers with different PLGA block lengths were synthesized using in-situ ring-opening polymerization of D,L-lactide and glycolide with tin(II) 2-ethylhexanoate ($Sn(Oct)_2$) catalyst. PLGA-F68-PLGA pentablock copolymers were characterized by $^1H$- and $^{13}C$-NMR, GPC, and TGA. The numbers (2m, 2n) of repeating units for lactic acid and glycolic acid inside PLGA segments were obtained as (48, 17), (90, 23), (125, 40), (180, 59), and (246, 64), with $^1H$-NMR measurement. From NMR data, the resultant molecular weights were determined in the range of 12,700-29,700, which were similar to those obtained from GPC. Polydispersity index was increased in the range of 1.32-1.91 as the content of PLGA blocks increased. TG and DTG thermograms showed discrete degradation traces for PLGA and F68 blocks, which indicate the weight fractions of PLGA blocks in pentablock copolymers can be calculated by TG profile and it is possible to remove PLGA block selectively. Hydrodynamic radius and radius of gyration of pentablock copolymer micelle were obtained in the range of 46-68 nm and 31-49 nm, respectively, in very dilute (i.e. 0.005 wt %) aqueous solution of THF:$H_2O$ = 10:90 by volume at $25^{\circ}C$.

패류로부터 분리된 젖산균에 의한 젖산의 생산

강창호(Chang-Ho Kang),정호건(Ho Geon Jung),구자룡(Ja-Ryong Koo),소재성(Jae-Seong So) 한국생물공학회 2015 KSBB Journal Vol.30 No.4

Lactic acid and its derivatives are widely used in the food, pharmaceutical, and cosmetic industries. It is also a major raw material for the production of poly-lactic acid (PLA), a biodegradable and environmentally friendly polymer and a possible alternative to synthetic plastics derived from petroleum. For PLA production by new strains of lactic acid bacteria (LAB), we screened LAB isolates from shellfish. A total of 51 LAB were isolated from 7 types of shellfishes. Lactic acid production of individual isolates was examined using high-performance liquid chromatography using a Chiralpak MA column and an ultraviolet detector. Lactobacillus plantarum T-3 was selected as the most stress-resistant strain, with minimal inhibition concentrations of 1.2 M NaCl, 15% ethanol, and 0.0020% hydrogen peroxide. In a 1 L fermentation experiment, D-lactic acid production of 19.91 g/L fermentation broth was achieved after 9 h cultivation, whereas the maximum production of total lactic acid was 41.37 g/L at 24 h.

1P-9 Synthesis and Macromolecular Structure Control of High Molecular Weight Poly(lactic-co-glycolic acid)s Through Direct Polycondensation

( Muhammad Ayyoob ),김영준 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

PLGA, poly(lactic-co-glycolic acid) is a biodegradable copolymer of lactic acid and glycolic acid. PLGAs are degradable to anodyne products under physiological environment. Until recently, most of the PLGAs are synthesized via ring opening copolymerization of lactide and glycolide. Preparation of lactide and glycolide from oligomers of lactic acid and glycolic acid is a complex, multistep and costly process. Direct esterification is a suitable alternative synthesis route, but unfortunately, not well explored yet due to poor thermal stability of PLGA. Our research is aimed on the adjustable properties of PLGA for orthopedic implants, biomedical application and drug delivery via macromolecular structural changes. In present work, we successfully synthesized the highmolecular-weight PLGA 50/50 by direct polycondensation in melt, in the presence of tin chloride dihydrate and methanesulfonic acid. The copolymer then characterized for NMR, intrinsic viscosity and thermal properties.

우측 이마에 필러 주입 후 발생한 시력 소실 1예

조용운,정인영,박종문,유지명,김성재,서성욱,한용섭.Yong Wun Cho. MD. In Young Chung. MD. PhD. Jong Moon Park. MD. PhD. Ji Myong Yoo. MD. PhD. Seong Jae Kim. MD. PhD. Seong Wook Seo. MD. PhD. Yong Seop Han. MD. PhD. 대한안과학회 2014 대한안과학회지 Vol.55 No.8

Purpose: We report a case of visual loss after the injection of poly-L-lactic acid filler into the right forehead area for cosmetic purposes. Case summary: A 46-year-old female patient visited our clinic due to sudden visual disturbance and dysesthesia on the right forehead and cheek. Her best corrected visual acuity was no light perception in the right eye and 20/20 in the left eye. Visual acuity in her right eye was not corrected. An afferent papillary defect in the right eye and paralysis of oculomotor muscles were observed. Fundus exam revealed a pale optic nerve and turbid retina on the posterior pole. The retinal vessels were narrowed. A papule 1 cm to the lateral margin of the right eyebrow due to the needle injection was found and no other visible skin abnormalities were observed. She had a cosmetic poly-L-lactic acid filler injection into the right forehead area immediately before the visual disturbance occurred. Fluorescent angiography showed occlusion of the right retinal artery and blood flow defects on the retina and choroid were present. The patient was followed up for 6 months and visual acuity and dysesthesia in her right forehead and cheek did not improve. Conclusions: Several cases of visual loss have occurred after injection of filler on the glabella and forehead for cosmetic purposes. However, most of the complications were observed after the use of hyaluronic fillers and not due to poly-L-lactic acid filler. This is the first case report of visual loss caused by poly-L-lactic acid filler in South Korea in a normal patient. Hence, consideration of complications when using this type of fillers is important. J Korean Ophthalmol Soc 2014;55(8):1253-1256

Effect of Thermoresponsive Poly(L-lactic acid)– poly(ethylene glycol) Gel Injection on Left Ventricular Remodeling in a Rat Myocardial Infarction Model

Shota Somekawa,Atsushi Mahara,Kazunari Masutani,Yoshiharu Kimura,Hiroshi Urakawa,Tetsuji Yamaoka 한국조직공학과 재생의학회 2017 조직공학과 재생의학 Vol.14 No.5

Some gel types have been reported to prevent left ventricular (LV) remodeling in myocardial infarction (MI) animal models. In this study, we tested biodegradable thermoresponsive gels. Poly(L-lactic acid)–poly(ethylene glycol) (PLLA–PEG) and poly(D-lactic acid)–poly(ethylene glycol) (PDLA–PEG) were synthesized by the polycondensation of Land D-lactic acids in the presence of PEG and succinic acid. Each of these block copolymers was used to prepare particles dispersed in an aqueous medium and mixed together to obtain a PLLA–PEG/PDLA–PEG suspension, which was found to show a sol-to-gel transition around the body temperature by the stereocomplex formation of enantiomeric PLLA and PDLA sequences. In the present study, the G0 of the PLLA–PEG/PDLA–PEG suspension in the rheological measurement remained as low as 1 Pa at 20 C and increased 2 kPa at 37 C. The sol–gel systems of PLLA–PEG/PDLA–PEG might be applicable to gel therapy. The effect of the PLLA–PEG/PDLA–PEG gel injection was compared with that of a calciumcrosslinked alginate gel and saline in a rat MI model. The percent fractional shortening improved in the PLLA–PEG/ PDLA–PEG (20.8 ± 4.1%) and alginate gel (21.1 ± 4.8%) compared with the saline (14.2 ± 2.8%) with regard to the echocardiograph 4 weeks after the injection (p\0.05). There were reduced infarct sizes in both PLLA–PEG/PDLA–PEG gel and alginate gel compared with the saline injection (p\0.05). Moreover, a greater reduction in LV cavity area was observed with the PLLA–PEG/PDLA–PEG gel than with the alginate gel (p = 0.06). These results suggest that the PLLA– PEG/PDLA–PEG gel should have high therapeutic potential in gel therapy for LV remodeling after MI.