1
|
Malunavicius V, Padaiga A, Stankeviciute J, Pakalniskis A, Gudiukaite R. Engineered Geobacillus lipolytic enzymes - Attractive polyesterases that degrade polycaprolactones and simultaneously produce esters. Int J Biol Macromol 2023; 253:127656. [PMID: 37884253 DOI: 10.1016/j.ijbiomac.2023.127656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/19/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023]
Abstract
Plastic pollution is one of the biggest environmental problems plaguing the modern world. Polyester-based plastics contribute significantly to this ecological safety concern. In this study, lipolytic biocatalysts GD-95RM and GDEst-lip developed based on lipase/esterase produced by Geobacillus sp. 95 strain were applied for the degradation of polycaprolactone films (Mn 45.000 (PCL45000) and Mn 80.000 (PCL80000)). The degradation efficiency was significantly enhanced by the addition of short chain alcohols. Lipase GD-95RM (1 mg) can depolymerize 264.0 mg and 280.7 mg of PCL45000 and PCL80000, films respectively, in a 24 h period at 30 °C, while the fused enzyme GDEst-lip (1 mg) is capable of degrading 145.5 mg PCL45000 and 134.0 mg of PCL80000 films in 24 h. The addition of ethanol (25 %) improves the degradation efficiency ~2.5 fold in the case of GD-95RM. In the case of GDEst-lip, 50 % methanol was found to be the optimal alcohol solution and the degradation efficiency was increased by ~3.25 times. The addition of alcohols not only increased degradation speeds but also allowed for simultaneous synthesis of industrially valuable 6-hydroxyhexonic acid esters. The suggested system is an attractive approach for removing of plastic waste and supports the principles of bioeconomics.
Collapse
Affiliation(s)
- Vilius Malunavicius
- Institute of Biosciences, Life Sciences Center, Vilnius University, Sauletekis avenue 7, LT-10257 Vilnius, Lithuania
| | - Antanas Padaiga
- Institute of Biosciences, Life Sciences Center, Vilnius University, Sauletekis avenue 7, LT-10257 Vilnius, Lithuania
| | - Jonita Stankeviciute
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Sauletekis avenue 7, LT-10257 Vilnius, Lithuania
| | - Andrius Pakalniskis
- Institute of Chemistry, Vilnius University, Naugarduko Str. 24, LT-03225 Vilnius, Lithuania
| | - Renata Gudiukaite
- Institute of Biosciences, Life Sciences Center, Vilnius University, Sauletekis avenue 7, LT-10257 Vilnius, Lithuania.
| |
Collapse
|
2
|
Irizar A, Amorim MJB, Fuller KP, Zeugolis DI, Scott-Fordsmand JJ. Environmental fate and effect of biodegradable electro-spun scaffolds (biomaterial)-a case study. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2018; 29:51. [PMID: 29713809 DOI: 10.1007/s10856-018-6063-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/18/2018] [Indexed: 06/08/2023]
Abstract
Poly-ε-caprolactone (PCL) based medical devices are increasingly produced and thus, their presence in the environment is likely to increase. The present study analysed the biodegradation of PCL electro-spun scaffolds (alone) and PCL electro-spun scaffolds coated with human recombinant (hR) collagen and Bovine Achilles tendon (BAT) collagen in sewage sludge and in soil. Additionally, an eco-toxicological test with the model organism Enchytraeus crypticus was performed to assess environmental hazard of the produced materials in soils. The electro-spun scaffolds were exposed to activated sludge and three different soils for various time periods (0-7-14-21-28-56-180 days); subsequently the degradation was determined by weight loss and microscopical analysis. Although no toxicity occurred in terms of Enchytraeus crypticus reproduction, our data indicate that biodegradation was dependent on the coating of the material and exposure condition. Further, only partial PCL decomposition was possible in sewage treatment plants. Collectively, these data indicate that electro-spun PCL scaffolds are transferred to amended soils.
Collapse
Affiliation(s)
- A Irizar
- Department of Bioscience, Aarhus University, Vejlsoevej 25, DK-8600, Silkeborg, Denmark
| | - M J B Amorim
- Department of Biology and CESAM, University of Aveiro, 3810-193, Aveiro, Portugal
| | - K P Fuller
- Regenerative, Modular and Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland
- Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland
| | - D I Zeugolis
- Regenerative, Modular and Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland
- Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland
| | - J J Scott-Fordsmand
- Department of Bioscience, Aarhus University, Vejlsoevej 25, DK-8600, Silkeborg, Denmark.
| |
Collapse
|
3
|
Kempe K. Chain and Step Growth Polymerizations of Cyclic Imino Ethers: From Poly(2‐oxazoline)s to Poly(ester amide)s. MACROMOL CHEM PHYS 2017. [DOI: 10.1002/macp.201700021] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kristian Kempe
- ARC Centre of Excellence in Convergent Bio‐Nano Science & Technology Monash Institute of Pharmaceutical Sciences Monash University Parkville VIC 3052 Australia
| |
Collapse
|
4
|
Lakshmanan R, Krishnan UM, Sethuraman S. Multidimensional nanofibrous scaffolds of poly(lactide-co-caprolactone) and poly(ethyl oxazoline) with improved features for cardiac tissue engineering. Nanomedicine (Lond) 2015; 10:3451-67. [DOI: 10.2217/nnm.15.143] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Aim: The aim of the study is to develop scaffolds that mimic native tissue properties for effective regeneration of the myocardium, which is affected by the gradual thinning of left ventricular tissue after an infarction. Materials & methods: Heterogenous nanofibrous scaffolds made of poly(lactide-co-caprolactone) and poly(ethyl oxazoline) were characterized for physico-chemical properties. The biocompatibility of the scaffolds was evaluated by studying the adhesion, proliferation and differentiation of H9c2 cells. Results: The scaffolds mimic the cardiac extracellular matrix and showed enhanced tensile strength, improved cell compatibility along with the expression of cardiac marker proteins. Conclusion: Our experimental data confirmed the importance of native tissue architecture and mechanical strength for improved cell response in cardiac tissue engineering.
Collapse
Affiliation(s)
- Rajesh Lakshmanan
- Centre for Nanotechnology & Advanced Biomaterials, School of Chemical & Biotechnology, SASTRA University, Thanjavur – 613 401, India
| | - Uma Maheswari Krishnan
- Centre for Nanotechnology & Advanced Biomaterials, School of Chemical & Biotechnology, SASTRA University, Thanjavur – 613 401, India
| | - Swaminathan Sethuraman
- Centre for Nanotechnology & Advanced Biomaterials, School of Chemical & Biotechnology, SASTRA University, Thanjavur – 613 401, India
| |
Collapse
|
5
|
|
6
|
Ruckh TT, Carroll DA, Weaver JR, Popat KC. Mineralization content alters osteogenic responses of bone marrow stromal cells on hydroxyapatite/polycaprolactone composite nanofiber scaffolds. J Funct Biomater 2012; 3:776-98. [PMID: 24955747 PMCID: PMC4030926 DOI: 10.3390/jfb3040776] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 09/25/2012] [Accepted: 10/24/2012] [Indexed: 02/07/2023] Open
Abstract
Synthetic tissue scaffolds have a high potential impact for patients experiencing osteogenesis imperfecta. Using electrospinning, tissue scaffolds composed of hydroxyapatite/polycaprolactone (HAp/PCL) composite nanofibers were fabricated with two different HAp concentrations—1% and 10% of the solid scaffold weight. After physico-chemical scaffold characterization, rat bone marrow stromal cells were cultured on the composite scaffolds in maintenance medium and then in osteogenic medium. Quantitative PCR, colorimetric assays, immunofluorescent labeling, and electron microscopy measured osteogenic cell responses to the HAp/PCL scaffolds. In maintenance conditions, both Hap/PCL scaffolds and control scaffolds supported cell colonization through seven days with minor differences. In osteogenic conditions, the 10% HAp scaffolds exhibited significantly increased ALP assay levels at week 3, consistent with previous reports. However, qPCR analysis demonstrated an overall decrease in bone matrix-associated genes on Hap/PCL scaffolds. Osteopontin and osteocalcin immunofluorescent microscopy revealed a trend that both mineralized scaffolds had greater amounts of both proteins, though qPCR results indicated the opposite trend for osteopontin. Additionally, type I collagen expression decreased on HAp scaffolds. These results indicate that cells are sensitive to minor changes in mineral content within nanofibers, even at just 1% w/w, and elucidating the sensing mechanism may lead to optimized osteogenic scaffold designs.
Collapse
Affiliation(s)
- Timothy T Ruckh
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA.
| | - Derek A Carroll
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA.
| | - Justin R Weaver
- Department of Chemical Engineering, Colorado State University, Fort Collins, CO 80523, USA.
| | - Ketul C Popat
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA.
| |
Collapse
|
7
|
Ruckh TT, Floreani RA, Carroll DA, Mikhova K, Bryers JD, Popat KC. Antimicrobial effects of nanofiber poly(caprolactone) tissue scaffolds releasing rifampicin. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2012; 23:1411-1420. [PMID: 22407002 PMCID: PMC3490623 DOI: 10.1007/s10856-012-4609-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 03/01/2012] [Indexed: 05/31/2023]
Abstract
This study quantified the antibiotic release kinetics and subsequent bactericidal efficacy of rifampicin (RIF) against Gram-positive and Gram-negative bacteria under in vitro static conditions. Antibiotic-loaded scaffolds were fabricated by electrospinning poly(caprolactone) (PCL) with 10% or 20% (w/w) RIF. Scaffold fiber diameter and RIF loading were characterized, and RIF release kinetics were measured. RIF-releasing and RIF-free scaffolds were inoculated with Pseudomonas aeruginosa and Staphylococcus epidermidis, and the suspended concentration live and dead bacteria were determined by fluorescent microscopy. Adherent bacteria and biofilm formation were examined using scanning electron microscopy. Mean fiber diameters were 557 ± 399 nm for RIF-free, 402 ± 225 nm for 10% RIF, and 665 ± 402 nm for 20% RIF scaffolds. RIF release kinetics exhibited a short-burst release during the first hour, followed by a 7 h, zero-order release during which both RIF scaffolds released ~50% of their initial RIF mass loading. P. aeruginosa and S. epidermidis suspended cell populations proliferated in accordance with logarithmic growth models when exposed to control scaffolds; however both RIF-containing scaffolds completely inhibited bacterial growth in suspension and, subsequently, prevented biofilm formation within the scaffolds through the first 6 h.
Collapse
Affiliation(s)
- Timothy T. Ruckh
- School of Biomedical Engineering, Colorado State University, Fort
Collins, CO 80523-1376, USA
| | - Rachael A. Floreani
- Department of Bioengineering, University of Washington, Seattle, WA
98195-5061, USA
| | - Derek A. Carroll
- Department of Mechanical Engineering, Colorado State University,
Campus Delivery, Fort Collins, CO 80523-1374, USA
| | - Krasimira Mikhova
- Department of Bioengineering, University of Washington, Seattle, WA
98195-5061, USA
| | - James D. Bryers
- Department of Bioengineering, University of Washington, Seattle, WA
98195-5061, USA
| | - Ketul C. Popat
- School of Biomedical Engineering, Colorado State University, Fort
Collins, CO 80523-1376, USA. Department of Mechanical Engineering, Colorado
State University, Campus Delivery, Fort Collins, CO 80523-1374, USA
| |
Collapse
|
8
|
Seppälä J, Korhonen H, Hakala R, Malin M. Synthesis of Novel Chain Extended and Crosslinked Polylactones for Tissue Regeneration and Controlled Release Applications. ACTIVE IMPLANTS AND SCAFFOLDS FOR TISSUE REGENERATION 2011. [DOI: 10.1007/8415_2010_52] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
|
9
|
Ruckh TT, Kumar K, Kipper MJ, Popat KC. Osteogenic differentiation of bone marrow stromal cells on poly(epsilon-caprolactone) nanofiber scaffolds. Acta Biomater 2010; 6:2949-59. [PMID: 20144747 DOI: 10.1016/j.actbio.2010.02.006] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 01/28/2010] [Accepted: 02/01/2010] [Indexed: 12/18/2022]
Abstract
Nanofiber poly(epsilon-caprolactone) (PCL) scaffolds were fabricated by electrospinning, and their ability to enhance the osteoblastic behavior of marrow stromal cells (MSCs) in osteogenic media was investigated. MSCs were isolated from Wistar rats and cultured on nanofiber scaffolds to assess short-term cytocompatibility and long-term phenotypic behavior. Smooth PCL substrates were used as control surfaces. The short-term cytocompatibility results indicated that nanofiber scaffolds supported greater cell adhesion and viability compared with control surfaces. In osteogenic conditions, MSCs cultured on nanofiber scaffolds also displayed increased levels of alkaline phosphatase activity for 3 weeks of culture. Calcium phosphate mineralization was substantially accelerated on nanofiber scaffolds compared to control surfaces as indicated through von Kossa and calcium staining, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Increased levels of intra- and extracellular levels of osteocalcin and osteopontin were observed on nanofiber scaffolds using immunofluorescence techniques after 3 weeks of culture. These results demonstrate the enhanced tissue regeneration property of nanofiber scaffolds, which may be of potential use for engineering osteogenic scaffolds for orthopedic applications.
Collapse
Affiliation(s)
- Timothy T Ruckh
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | | | | | | |
Collapse
|
10
|
Luo H, Meng X, Cheng C, Dong Z, Zhang S, Li B. Enzymatic Degradation of Supramolecular Materials Based on Partial Inclusion Complex Formation between α-Cyclodextrin and Poly(ε-caprolactone). J Phys Chem B 2010; 114:4739-45. [DOI: 10.1021/jp1001836] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haiya Luo
- State Key Laboratory of Polymer Materials Engineering (Sichuan University), Polymer Research Institute of Sichuan University, Chengdu 610065, People’s Republic of China, and Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Xianwei Meng
- State Key Laboratory of Polymer Materials Engineering (Sichuan University), Polymer Research Institute of Sichuan University, Chengdu 610065, People’s Republic of China, and Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Cong Cheng
- State Key Laboratory of Polymer Materials Engineering (Sichuan University), Polymer Research Institute of Sichuan University, Chengdu 610065, People’s Republic of China, and Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Zhenqiang Dong
- State Key Laboratory of Polymer Materials Engineering (Sichuan University), Polymer Research Institute of Sichuan University, Chengdu 610065, People’s Republic of China, and Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Sheng Zhang
- State Key Laboratory of Polymer Materials Engineering (Sichuan University), Polymer Research Institute of Sichuan University, Chengdu 610065, People’s Republic of China, and Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| | - Bangjing Li
- State Key Laboratory of Polymer Materials Engineering (Sichuan University), Polymer Research Institute of Sichuan University, Chengdu 610065, People’s Republic of China, and Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
| |
Collapse
|
11
|
Martins AM, Pham QP, Malafaya PB, Sousa RA, Gomes ME, Raphael RM, Kasper FK, Reis RL, Mikos AG. The role of lipase and alpha-amylase in the degradation of starch/poly(epsilon-caprolactone) fiber meshes and the osteogenic differentiation of cultured marrow stromal cells. Tissue Eng Part A 2009; 15:295-305. [PMID: 18721077 DOI: 10.1089/ten.tea.2008.0025] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The present work studies the influence of hydrolytic enzymes (alpha-amylase or lipase) on the degradation of fiber mesh scaffolds based on a blend of starch and poly(epsilon-caprolactone) (SPCL) and the osteogenic differentiation of osteogenic medium-expanded rat bone marrow stromal cells (MSCs) and subsequent formation of extracellular matrix on these scaffolds under static culture conditions. The biodegradation profile of SPCL fiber meshes was investigated using enzymes that are specifically responsible for the enzymatic hydrolysis of SPCL using concentrations similar to those found in human serum. These degradation studies were performed under static and dynamic conditions. After several degradation periods (3, 7, 14, 21, and 30 days), weight loss measurements and micro-computed tomography analysis (specifically porosity, interconnectivity, mean pore size, and fiber thickness) were performed. The SPCL scaffolds were seeded with rat MSCs and cultured for 8 and 16 days using complete osteogenic media with and without enzymes (alpha-amylase or lipase). Results indicate that culture medium supplemented with enzymes enhanced cell proliferation after 16 days of culture, whereas culture medium without enzymes did not. No calcium was detected in groups cultured with alpha-amylase or without enzymes after each time period, although groups cultured with lipase presented calcium deposition after the eighth day, showing a significant increase at the sixteenth day. Lipase appears to positively influence osteoblastic differentiation of rat MSCs and to enhance matrix mineralization. Furthermore, scanning electron microscopy images showed that the enzymes did not have a deleterious effect on the three-dimensional structure of SPCL fiber meshes, meaning that the scaffolds did not lose their structural integrity after 16 days. Confocal micrographs have shown cells to be evenly distributed and infiltrated within the SPCL fiber meshes up to 410 microm from the surface. This study demonstrates that supplementation of culture media with lipase holds great potential for the generation of bone tissue engineering constructs from MSCs seeded onto SPCL fiber meshes, because lipase enhances the osteoblastic differentiation of the seeded MSCs and promotes matrix mineralization without harming the structural integrity of the meshes over 16 days of culture.
Collapse
Affiliation(s)
- Ana M Martins
- 3Bs Research Group-Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Campus de Gualtar, Braga, Portugal
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Pulkkinen M, Malin M, Böhm J, Tarvainen T, Wirth T, Seppälä J, Järvinen K. In vivo implantation of 2,2'-bis(oxazoline)-linked poly-epsilon-caprolactone: proof for enzyme sensitive surface erosion and biocompatibility. Eur J Pharm Sci 2008; 36:310-9. [PMID: 19022379 DOI: 10.1016/j.ejps.2008.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 09/22/2008] [Accepted: 10/16/2008] [Indexed: 10/21/2022]
Abstract
Previously, we have demonstrated that 2,2-bis(2-oxazoline) linked poly-epsilon-caprolactone (PCL-O) is degraded in vitro enzymatically by surface erosion which could enable the novel use of this material for drug delivery and other biomedical applications. In this study, degradation, erosion (weight loss) and toxicity of PCL-O poly(ester-amide)s were evaluated in vivo. PCL and three PCL-O polymers with different PCL block lengths (M(n): 1500, 3900, 7500 g/mol) were melt-pressed in the form of discs and implanted subcutaneously in Wistar rats (dose approximately 340 mg/kg) for 1, 4 and 12 weeks. With implantation for 12 weeks, up to 16.5% weight loss of polymer discs was measured for the most extensively linked PCL-O polymer (block length 1500 g/mol) whereas practically no weight loss was observed with the other polymers. NMR, DSC and SEC studies as well as SEM micrographs before and after implantation and in vitro hydrolysis studies indicate that enzyme based surface erosion of PCL-O polymers occurred in vivo. The in vivo evaluation based on results from hematology, clinical chemistry and histology of the implantation area and main organs (i.e. heart, lung, liver, kidney, spleen and brain) demonstrated that PCL-O polymers are biocompatible and safe, enzyme sensitive biomaterials.
Collapse
Affiliation(s)
- Mika Pulkkinen
- Department of Pharmaceutics, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland.
| | | | | | | | | | | | | |
Collapse
|
13
|
Pulkkinen M, Palmgrén JJ, Auriola S, Malin M, Seppälä J, Järvinen K. High-performance liquid chromatography/electrospray ionization tandem mass spectrometry for characterization of enzymatic degradation of 2,2'-bis(2-oxazoline)-linked poly-epsilon-caprolactone. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:121-129. [PMID: 18085511 DOI: 10.1002/rcm.3336] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This paper describes a straightforward and rapid on-line characterization using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS(n)) of the enzymatic degradation products of 2,2'-bis(2-oxazoline)-linked poly-epsilon-caprolactone (PCL-O). These new PCL-O polymers are expected to be used in a variety of pharmaceutical and biomedical applications since they are degraded enzymatically by surface erosion. PCL-O was polymerized in a three-step reaction and characterized by (1)H-NMR and size-exclusion chromatography (SEC). Solvent cast polymer films were exposed to enzymatic degradation in phosphate buffer (pH 7.5, 1% pancreatin). The enzymatic degradation of the polymer produced a wide variety of water-soluble oligomers which were separated and identified by HPLC/ESI-MS(n). Optimization of the gradient HPLC method resulted in effective separation of the oligomers. Furthermore, specific structures of the oligomers were clearly identified by tandem mass spectrometry. According to these results, ester bonds seem to be most sensitive to enzymatic degradation and, correspondingly, pancreatic lipase seems to be mainly responsible for the enzymatic erosion of the PCL-O films. This novel mass spectrometric method provides important knowledge about the enzymatic degradation process and structure of the polymer which is difficult to ascertain by other conventional methods.
Collapse
Affiliation(s)
- Mika Pulkkinen
- Department of Pharmaceutics, University of Kuopio, Kuopio, Finland.
| | | | | | | | | | | |
Collapse
|