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PubMed1991

Spin labels as a probe of the molecular environment of covalently bound ligands in an hydrophobic and an hydrophilic polymer.

The molecular motions of spin-labelled ligands covalently bound by spacer groups to an hydrophobic and an hydrophilic polymer matrix were evaluated by ESR spectroscopy. The ligands were prepared by alkylation of 4-N-methylamino-TEMPO with the omega-bromocarboxylic esters, Br(CH2)nCOOEt, n = 1,4 and 10. The hydrolysed esters were coupled to a cross-linked aminoethylated polyacrylamide hydrogel (n = 1,4,10) and to a surface hydroxylated elastomeric polyester (n = 4). The rotational correlation times (tau c) of the nitroxide label in the hydrogels were measured in the dry state and after exposure to water at pH 4, 7.4 and 10.5. The tau c of the nitroxide label was insensitive to the length of the spacer group and to the degree of protonation of the tertiary amino group of the ligand. There was no evidence of self-association of the ligand and spacer, or more than a single phase within the polyacrylamide hydrogel. The tau c of the nitroxide labelled polyester was similarly insensitive to pH, but was sensitive to organic solvents. The low mobility of the spin label and its high concentration were consistent with the spin label being covalently bound within the hydrophobic polyester matrix to a depth of at least 5 microns.

Acrylic Resins↗

PubMed1991

New collagen implant as dural substitute.

A collagen prosthesis was developed as a dural substitute. It is composed of a Dallop matrix-polyester knitted net with radiation cross-linked collagen on both sides. Collagen was derived from enzyme-treated bovine Achilles tendons. Improved hydrophilic properties of the polyester base ensuring stronger adhesion to collagen were obtained by pretreating the net with a low-temperature plasma in air. Cross-linking of collagen and simultaneous sterilization of the final prosthesis was obtained by irradiation with 5 MeV electrons. Measurement of the physicochemical parameters of the prostheses gives satisfactory results. In vitro biological examinations show that the prostheses are non-toxic. The results of in vivo clinical experimental evaluation are positive and lead to the conclusion that the collagen-covered polyester net does not differ significantly from Zenoderm dural substitute.

Adhesiveness↗

PubMed2004

Distinctive bacteria-binding property of cloth materials.

BACKGROUND: Nosocomial infections may be caused by pathogens that are transmitted from the hands or clothes of hospital personnel. Handwashing has been evaluated as effective against the spread of pathogens, but transmission through clothes has been little investigated. Evaluation of bacterial adherence to clothes is difficult because of the nonuniform amount of water absorbance by cloth. Therefore, we measured binding of bacteria to cloth fibers made of cotton, nylon, polyester, acrylic, or sheep's wool and tried to characterize bacterial binding to cloth. METHODS: We chose to study the opportunistic pathogens Staphylococcus aureus and Pseudomonas aeruginosa. Cloth fibers were incubated with bacterial suspensions in silicone-coated tubes. We evaluated the reduction of numbers of bacteria in solutions incubated with the fibers and calculated binding ratios of bacteria to the fibers. RESULTS: Polyester or acrylic fibers bound S aureus and P aeruginosa at high ratios (>80%), but cotton fibers bound them at low ratios (<10%). Nylon fibers bound S aureus at low ratios, but P aeruginosa at intermediate ratios. CONCLUSION: The results suggested that polyester, acrylic, or wool clothes could be good carriers of S aureus and P aeruginosa and thus should be covered with cotton clothes to minimize the spread of the pathogens.

Cells, Cultured↗

PubMed2004

Use of biomass sorbents for oil removal from gas station runoff.

The use of biomass sorbents, which are less expensive and more biodegradable than synthetic sorbents, for oil removal from gas station runoff was investigated. A bench-scale flume experiment was conducted to evaluate the oil removal and retention capabilities of the biomass sorbents which included kapok fiber, cattail fiber, Salvinia sp., wood chip, rice husk, coconut husk, and bagasse. Polyester fiber, a commercial synthetic sorbent, was also experimented for comparison purpose. Oil sorption and desorption tests were performed at a water flow rate of 20 lmin-1. In the oil sorption tests, a 50 mgl(-1) of used engine oil-water mixture was synthesized to simulate the gas station runoff. The mass of oil sorbed for all sorbents, except coconut husk and bagasse, was greater than 70%. Cattail fiber and polyester fiber were the sorbents that provided the least average effluent oil concentrations. Oil selectivity (hydrophobic properties) and physical characteristics of the sorbents are the two main factors that influence the oil sorption capability. The used sorbents from the sorption tests were employed in the desorption tests. Results indicated that oil leached out of all the sorbents tested. Polyester fiber released the highest amount of oil, approximately 4% (mass basis) of the oil sorbed.

Adsorption↗

PubMed2005

Synthesis, characterization of novel injectable drug carriers and the antitumor efficacy in mice bearing Sarcoma-180 tumor.

New unsaturated polyesters of poly(fumaric acid-glycol-dodecanedioic acid) P(FA-GLY-DDDA) copolymers, poly(fumaric acid-glycol-brassylic acid) P(FA-GLY-BA) copolymers, poly(fumaric acid-glycol-tetradecanedioic acid) P(FA-GLY-TA) copolymers and poly(fumaric acid-glycol-pentadecanedioic acid) P(FA-GLY-PA) copolymers were prepared by melt polycondensation of the corresponding mixed monomers: fumaric acid, glycol and one of C(12-15) dibasic acids. The copolymers were characterized by FT-IR, gel permeation chromatography (GPC), and the surface structure of unsaturated polyesters after solidify were studied by atomic force microscopy (AFM). The molecular structure and composition of the unsaturated polyesters were determined by 1H NMR spectroscopy. In vitro studies showed that some of the copolymers are degradable in phosphate buffer at 37 degrees C and have properly drug release rate as drug carriers. The biocompatibility of P(FA-GLY-DDDA) and P(FA-GLY-BA) copolymers under mice skin was also evaluated, macroscopic observation and microscopic analysis demonstrated that the copolymer is biocompatible and well tolerated in vivo. Antitumor efficacy of P(FA-GLY-DDDA) copolymers and P(FA-GLY-BA) copolymers containing 5% adriamycin hydrochloride (ADM) in mice bearing Sarcoma-180 tumor exhibited increased volume doubling time (VDT) (22+/-1.5 days and 24+/-2.5 days) compared to plain subcutaneous injection of ADM (7+/-0.9 days). The antitumor efficacy of injecting P(FA-GLY-DDDA)-ADM inside tumor twice intervened in 22 days exhibited an especially increased cytotoxic effect as revealed by increased VDT (33+/-2.5 days), and the antitumor efficacy of injecting P(FA-GLY-BA)-ADM inside tumor twice intervened in 24 days exhibited an especially increased cytotoxic effect as revealed by increased VDT (35+/-1.5 days). The studies suggested that P(FA-GLY-DDDA) copolymers and P(FA-GLY-BA) copolymers as effective and injectable carriers for antineoplastic drug like adriamycin hydrochloride have a very good foreground in the treatment of noumenon tumor.

Algorithms↗

PubMed2005

Carotid endarterectomy with a polyurethane patch versus primary closure: a prospective randomized study.

INTRODUCTION: The use of synthetic patch angioplasty during carotid endarterectomy (CEA) has been advocated to reduce restenosis, stroke, and death, but the type of material used is still being debated. This study compared rate of restenosis, neurologic events, and perioperative death in patients undergoing CEA with primary closure versus polyester urethane patch closure. PATIENTS AND METHODS: In a prospective randomized study, we compared patch angioplasty with polyester urethane (Vascular-patch, B. Braun Medical AG, Tuttlingen, Germany) to primary closure between February 1999 and March 2002 in 404 operations. Early (30-day) stroke and mortality rate, long-term restenosis, and neurologic events were compared in the two groups during 2.5 to 5 years of follow-up (median follow-up, 2 years). RESULTS: Primary closure was used in 216 operations, and patch angioplasty was used in 206. Clamping time was significantly shorter in the primary closure group ( P < .001). Perioperative mortality and neurologic events were similar in both groups (1.9% vs 3.9%, P = .21, odds ratio [OR], 2.1; 95% confidence interval [CI], 0.56 to 9.85). The rate of residual stenosis (> or =50%) at 0 or 3-month follow-up was significantly lower in the patch group (2 operations, 1.1%) compared with the primary closure group (17 operations, 8.9%) ( P = .001, OR, 0.114; 95% CI, 0.026 to 0.5). Multivariable logistic regression showed that only primacy closure was found to influence residual stenosis. Restenosis of 70% was significantly less in the patch angioplasty group (2.2% vs 8.6%) ( P = . 01, hazard ratio, 0.246; 95% CI, 0.08 to 0.75). No correlation was found between restenosis and gender, preoperative symptoms, or risk factors. CONCLUSIONS: Patch angioplasty with polyester urethane significantly reduced the restenosis rate ( P = . 01) compared with primary closure. Even though clamping time was longer, patching was not associated with more perioperative complications.

Aged↗

PubMed2005

High complication rate identified in sacrocolpopexy patients attributed to silicone mesh.

OBJECTIVES: To report on our experience using a preconfigured Y-shaped silicone-coated polyester mesh and polypropylene mesh for vaginal vault suspension. A variety of materials have been used for both open and laparoscopic sacrocolpopexy in the management of vaginal vault prolapse. Recently, a preconfigured Y-shaped silicone-coated polyester mesh was introduced to facilitate the vaginal cuff suspension to the sacrum. METHODS: We reviewed the data of 45 consecutive patients who underwent abdominal (n = 28) or laparoscopic (n = 17) sacrocolpopexy. Of the 45 patients, 21 underwent silicone mesh suspension of the vaginal cuff to the anterior sacrum, with a mean follow-up of 23 months (range 16 to 41). A comparative analysis was performed of 24 patients who underwent the same procedure with polypropylene mesh. RESULTS: Of the 21 patients in the silicone group, 5 (23.8%) have had a major complication (four vaginal mesh erosions and one mesh infection) after a median follow-up of 9.5 months (range 4 to 20). The presenting symptoms were persistent or new vaginal discharge and/or nonspecific pelvic pain. One patient underwent successful removal of the mesh transvaginally, but the rest required abdominal exploration. To date, the 24 patients who underwent vaginal cuff suspension with polypropylene mesh have had no vaginal mesh extrusions or infections, with a mean follow-up of 12 months (range 1 to 38). CONCLUSIONS: Silicone-coated polyester mesh has recently been associated with a high rate of vaginal erosion when used as a transvaginal suburethral sling. Our experience specifically with vaginal vault suspension corroborates this. We have abandoned the use of silicone mesh because of the unacceptably high extrusion rate and presently use polypropylene mesh.

Aged↗

PubMed1997

Effect of increased scrotal temperature on sperm production in normal men.

OBJECTIVE: To determine whether application of polyester-lined athletic supports to bring the testes closer to the abdomen increases scrotal temperature and decreases sperm production. DESIGN: Prospective clinical study. SETTING: University academic medical center. PATIENT(S): Twenty-one healthy male volunteers. INTERVENTION(S): The study consisted of a pretreatment period of 6 weeks, a treatment phase of 52 weeks, and a recovery phase until return to normal sperm production. During the treatment phase, the men wore polyester-lined athletic supports (single layer, double layer, or double layer impregnated with aluminum) throughout the day. MAIN OUTCOME MEASURE(S): Semen parameters and sperm function tests. RESULT(S): In all three groups of subjects, scrotal temperature was consistently increased by 0.8 to 1 degree C while the subjects were wearing the athletic supports. Mean sperm concentration; sperm motility, morphology, and viability; sperm hyperactivation; and ability of spermatozoa to penetrate zone-free hamster oocytes were not affected by the increase in scrotal temperature. CONCLUSION(S): The increase in scrotal temperature induced by polyester-lined athletic supports was insufficient to cause significant suppression of spermatogenesis or alteration of sperm function.

Adult↗

PubMed1998

Pubic symphysis repair strength in simulated bladder exstrophy using a sheep model.

OBJECTIVES: To investigate the mechanical strength of various pubic symphysis suture material in a simulated animal model of neonatal bladder exstrophy. METHODS: Neonatal lamb pelves, which are the approximate size of neonatal human pelves, were used. Twenty-four neonatal lamb pelves were divided into four equal groups. A midline symphysotomy was made through the cartilaginous pubic symphysis in three groups and repaired using two figure-of-eight sutures (size 0) placed through the cartilaginous pubis using polypropylene, braided polyester, or polyglactin. The fourth group served as the control. The pelves were then tested to ultimate load in pure tension at a strain rate of 0.25 mm/s until failure. RESULTS: There was a highly significant difference between the intact specimens and the repaired specimens (P = 0.0008). For the repaired specimens, there was a significant difference in the ultimate load normalized by pubic height between those repaired with polypropylene and polyglactin (P = 0.025), but not for those repaired with polypropylene and braided polyester (P = 0.11) or braided polyester and polyglactin (P = 0.11). CONCLUSIONS: Braided resorbable sutures are recommended for pubic symphysis repair, because they have a lower tendency to cut out of the cartilage.

Animals↗

PubMed2006

[Synthetic meshes for transvaginal surgical cure of genital prolapse: evaluation in 2005].

Since 1996, prosthetic meshes have become increasingly popular for transvaginal surgical cure of genital prolapse. In light of the growing number of proposed techniques and materials we reviewed the experience of the pioneers in order to provide surgeons with the most objective information available. We reviewed the literature indexed in Meline/PubMed and Current Contents retaining all work concerning resorbable and non-resorbable meshes. For the larger class of non-resorbable meshes we also reviewed articles by category of material, each type of mesh being carefully defined: different compositions of polypropylene, polyester, composite meshes and also insertion kits. Resorbable meshes were evaluated in two randomized studies which did not demonstrate better results than with simple folding known to have a high rate of recurrence. For polypropylene meshes, Marlex was studied in six trials which demonstrated a high rate of cure at one year but also a high rate of erosion which reached 25%. Use of Atrium was mentioned in three studies with a 6 to 12% recurrence rate and an erosion rate nearly reaching 20%. The majority of studies used Prolene and Gynemesh. Seventeen authors reported their experience, generally reviewing retrospective series, with recurrence rates of less than 10% for follow-up periods rarely greater than two years. A large variety of forms and sizes have been used, hindering comparisons. The rate of erosion was also quite variable, as high as 45%, demonstrating the need for a precise definition of erosion. Only recently have authors shown interest in the impact of prosthetic meshes on quality of life and sexual activity. An improvement is generally noted for defecation but the rate of dyspareunia has reached as high as 60%. Here again grades of prosthetic retraction should be better defined. Proposed to improve these phenomena, soft Prolene recently used by several authors does not appear to fulfil expectations. Since 2005, several precut polypropylene meshes have been proposed with an insertion kit. The Prolift kit has been followed prospectively in 100 patients undergoing regular surveillance. Surgipro has been used sporadically in small series but follow-up is still too short for proper assessment. Polyester meshes (Mersilene and Paritex) have been presented by three authors who have found them useful but reports have been vague concerning results and complications. Polytetrafluoroethylene has not been evaluated for transvaginal surgery, probably because of the poor tolerance of suburetral bands. For composite meshes, Vypro has been used by four authors who noted about 10% erosion but with a short follow-up insufficient to draw conclusions about the functional and anatomic outcome. Surfaced meshes, advocated for transvaginal treatments, have been studied in only two reports. Plevitex is a polypropylene mesh coated with collagen; another polyester composite with polyglactin 910. The rate of dyspareunia varied from 14 to 24%. Other composites with antiadherents or antiseptics are also proposed for transvaginal insertion but have not been studied. This work demonstrated the lack of sufficient evidence from prospective randomized trials and the lack of standardized techniques to draw any definite conclusions. While evidence is being accumulated on the lower rate of recurrence for anterior compartment prolapse, the lack of data on the rate of complications and patient quality of life is unacceptable for this functional surgery. We still have reservations about widespread use of synthetic meshes. A special chapter is detailed in appendix on post-operative complications. These new specific complications call to a new semiology, with a classification in 4 types and under-types, proposed by authors. Type 1: defects of healing. Type 2: the infection of the graft. Type 3: the shrinkage of the mesh. Type 4: erosions. Authors detail the symptoms of these 4 types as well as the prevention and the treatment of these complications.

Absorbable Implants↗

PubMedDate not supplied

Experimental evaluation of a new self-expanding patent ductus arteriosus occluder in a canine model.

PURPOSE: A new self-expanding patent ductus arteriosus (PDA) occluder was designed. MATERIALS AND METHODS: Percutaneous closure of surgically created aortopulmonary shunts was attempted in 19 dogs. The occlusion device consisted of a nitinol wire frame tightly woven into a cylinder with a flat retention disc. A polyester-filled frame was used in the last six procedures. A 6-F introducing sheath was advanced across the aortopulmonary conduit into the descending thoracic aorta. The prosthesis (attached on a stiff delivery cable) was advanced through the introducing sheath. The retention disc was first released in the descending thoracic aorta, then the cylindrical device frame was expanded within the conduit by withdrawing the sheath. RESULTS: Subtotal misplacement into the descending aorta occurred in one procedure (overall technical success rate, 95%), and one animal died before the 1-week follow-up. Complete angiographic shunt closure was achieved in seven of 18 (39%) animals at 30 minutes, 12 of 17 (71%) animals at 1 week, 14 of 17 (82%) animals at 1 month, and 11 of 12 (92%) animals at 3 months. Significantly higher 30-minute closure rates occurred with polyester-filled occluders compared with nonfilled occluders (five of five [100%] vs one of 13 [15%]; P = .002). Persistent shunt at 3 months occurred in only one nonfilled device (6%). In the remaining 16 animals, both orifices of the shunt were covered by a smooth glistening neoendothelium at postmortem examination. CONCLUSION: This device combines the advantages of small delivery system, easy placement, self-centering, and repositionability. Immediate shunt closure can be reliably accomplished with the polyester-filled prosthesis.

Alloys↗

PubMed1999

Preliminary results with a new vascular basket occluder in swine.

PURPOSE: To experimentally evaluate a new self-anchoring vascular occlusion device suitable for use in large, high-flow vessels. MATERIALS AND METHODS: A basket-shaped occluding device consisting of a nitinol frame (with or without polyester threads) covered with Dacron was evaluated in the common iliac arteries and abdominal aortae of normal pigs. One occluder was placed in each recipient vessel. Angiography was performed before and after placement of each occluder. RESULTS: Precise placement of the device was achieved in all cases. Mechanically, all but one occluder worked dependably. Angiographically, devices without polyester threads produced only partial occlusion. Devices with threads produced complete occlusion in all but one abdominal aorta, in which partial occlusion occurred because the occluder opened asymmetrically. Complete iliac arterial occlusion occurred within 2-8 minutes of placement and aortic occlusion was achieved within 8-20 minutes. At necropsy, all devices were found to be securely anchored against the vascular wall. CONCLUSION: Preliminary results indicate that this vascular basket occluder containing polyester threads is easy to place precisely, produces rapid embolization, and demonstrates good self-anchoring ability in a high-flow arterial model.

Angiography↗

PubMedDate not supplied

A study in relation to the random distribution of four fibre types on clothing (incorporating a review of previous target fibre studies).

A new target fibre study was undertaken building upon eight previous published studies, which are reviewed here. Fifty-eight items of outer clothing, obtained from households across England, were taped and searched for three types of commonly occurring fibres and one less common fibre type. The tapes were examined using a combination of automatic and manual searching. Any fibres similar to the target fibres were removed and examined using microspectrophotometry, comparison microscopy, thin layer chromatography (TLC) and fourier transform infrared spectroscopy (FTIR) where applicable. One polyester fibre, four acrylic fibres and eleven wool fibres were found that matched the three commonly occurring target fibre samples. None of the less common polyester fibres were found. One item had six matching wool fibres and another had the polyester fibre and an acrylic fibre recovered from it. The remaining eight fibres were each recovered from individual items. The results suggest that finding a large number of fibres that match a control is unlikely to happen by chance, which supports the findings of the previous target fibre studies.

Journal Article↗

PubMed1998

Production of cell-free xanthan fermentation broth by cell adsorption on fibers

Xanthan gum is a microbial polysaccharide widely used in food and oil-drilling industries. Xanthan gum produced from the current commercial fermentation process usually contains cells and cell debris, which lower the filterability of the xanthan solution and limit its applications. The production of cell-free xanthan gum fermentation broth is thus desirable. The feasibility of removing cells from the xanthan fermentation broth by cell adsorption to various woven fibrous materials was studied. It was found that both cotton and polyester fibers could be used to adsorb Xanthomonas campestris cells present in the fermentation broth either during batch fermentation or after the fermentation. Almost all cells were removed from the fermentation broth by adsorption to fibers. Cotton terry cloth had rough surfaces and was the preferred material for cell adsorption. Cell adsorption to cotton was faster than to polyester fibers. The adsorption kinetics can be modeled by a first-order rate equation. The adsorption rate constants were 30-40% higher for cotton than for polyester. Cell adsorption was not efficient in the absence of xanthan gum, suggesting that the exopolysaccharide, xanthan gum, was important for efficient cell adsorption to fibers.

Journal Article↗

PubMed2000

Biosynthesis, molecular structure, and domain architecture of potato suberin: a (13)C NMR study using isotopically labeled precursors.

Although suberin in potato wound periderm is known to be a polyester containing long-chain fatty acids and phenolics embedded within the cell wall, many aspects of its molecular structure and polymer-polymer connectivities remain elusive. The present work combines biosynthetic incorporation of site-specifically (13)C-enriched acetates and phenylalanines with one- and two-dimensional solid-state (13)C NMR spectroscopic methods to monitor the developing suberin polymer. Exogenous acetate is found to be incorporated preferentially at the carboxyl end of the aliphatic carbon chains, suggesting addition during the later elongation steps of fatty acid synthesis. Carboxyl-labeled phenylalanine precursors provide evidence for the concurrent development of phenolic esters and of monolignols typical of lignin. Experiments with ring-labeled phenylalanine precursors demonstrate a predominance of sinapyl and guaiacyl structures among suberin's phenolic moieties. Finally, the analysis of spin-exchange (solid-state NOESY) NMR experiments in ring-labeled suberin indicates distances of no more than 0.5 nm between pairs of phenolic and oxymethine carbons, which are attributed to the aromatic-aliphatic polyester and the cell wall polysaccharide matrix, respectively. These results offer direct and detailed molecular information regarding the insoluble intermediates of suberin biosynthesis, indicate probable covalent linkages between moieties of its polyester and polysaccharide domains, and yield a clearer overall picture of this agriculturally important protective material.

Carbon Isotopes↗

PubMed2006

Using trifluoroacetic acid to augment studies of potato suberin molecular structure.

Systematically varied reaction times and concentrations of trifluoroacetic acid (TFA) have been used to remove polysaccharides associated with suberin isolated from potato wound periderm, thereby augmenting spectroscopic determinations of the molecular structure of this protective plant polyester. Treatments with dilute TFA left a residual insoluble material for which both solid-state 13C and 1H NMR spectra displayed significant improvements in resolution without compromising the integrity of the protective plant polyester, whereas higher concentrations of TFA made it possible to achieve controlled hydrolysis of the suberin aliphatic or aromatic domains. Among the isolated fragments were two hydroxyphenyl derivatives reported previously in lignins and a novel aliphatic-aromatic ester trimer that is identified provisionally. Together these protocols help to characterize the carbohydrate types that are bound covalently to the suberin polyester and to identify the interunit covalent linkages among the aliphatic ester, phenolic, and carbohydrate moieties in suberized potato tissue. The strategies described herein may also advance molecular-level investigations of lignocellulosic materials or vegetable tissues that exhibit strengthened intercellular adhesion.

Indicators and Reagents↗

PubMed1998

Semicrystalline Polymers via Ring-Opening Polymerization: Preparation and Polymerization of Alkylene Phthalate Cyclic Oligomers.

Preparation of cyclic oligomeric alkylene phthalates via pseudo-high dilution condensation of alkylene diols with iso- and terephthaloyl chlorides and conversion to high molecular weight polyesters via ring-opening polymerization is described. Sterically unhindered amines such as quinuclidine or 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyze the condensation significantly faster than other tertiary amines and are useful for carrying out this conversion in high yield, in the first direct reaction of diol and diacid chloride to form cyclic polyesters. The mixtures of oligomeric cyclics melt at 150-200 degrees C, providing liquids of low viscosity. Ring-opening polymerization using tin or titanate catalysts affords high molecular weight polymers within minutes. Complete polymerization of PBT oligomeric cyclics can be achieved at 180-200 degreesC, significantly below the polymer's melting point of 225 degreesC, and with molecular weights as high as 445 x 10(3). Polymers formed via such a process are more crystalline than conventionally prepared polyesters.

Journal Article↗

PubMed2002

Effect of lipase treatment on the biocompatibility of microbial polyhydroxyalkanoates.

Films made from microbial polyesters polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) were treated by lipases and NaOH solution. The change of the polyester biocompatibility was evaluated by inoculating mouse fibroblast cell line L929 on films of PHB, PHBHHx and their blends. Polylactic acid (PLA) was used as a control. It was found that untreated PHB and PLA films gave a poor support to the growth of L929 cells, viable cell density ranged from 0.1x10(4}) to 0.7x10(4) per ml only. While films of pure PHBHHx and PHB blended with PHBHHx showed improved biocompatibility, viable cell density observed increased from 9.6x10(2) to 6x10(4) on blended films of PHB/PHBHHx in ratios of 0.9/0.1 to 0/1, respectively. This result showed PHBHHx has a better biocompatibility compared with PHB. Films of PHB, PLA and the blends treated with lipases and 1 N NaOH, respectively, showed an improved ability to support cell growth. Biocompatibility of PHB was approximately the same as PLA after the treatment, while PHBHHx and its dominant blends showed improved biocompatibility compared with PLA. The sensitivity of the treatments was reduced when PHBHHx content increased in the PHB/PHBHHx blends. All three lipase treatments demonstrated more biocompatibility increase on all the films compared with the results of NaOH treatment. Scanning electron microscopy showed that PHB films changed its surface from multi-porous to rough non-porous after the lipase or NaOH treatment. While PHBHHx films showed little change after these treatments. The results showed that the polyester surface morphology played an important role in affecting cell attachment and growth on these materials.

Journal Article↗