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Geng T, Xiao HC, Wang XC, Liu CT, Wu L, Guo YG, Dong BB, Turng LS. The Study on the Morphology and Compression Properties of Microcellular TPU/Nanoclay Tissue Scaffolds for Potential Tissue Engineering Applications. Polymers (Basel) 2023; 15:3647. [PMID: 37688273 PMCID: PMC10563071 DOI: 10.3390/polym15173647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/09/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
Thermoplastic polyurethane (TPU) materials have shown promise in tissue engineering applications due to their mechanical properties and biocompatibility. However, the addition of nanoclays to TPU can further enhance its properties. In this study, the effects of nanoclays on the microstructure, mechanical behavior, cytocompatibility, and proliferation of TPU/nanoclay (TPUNC) composite scaffolds were comprehensively investigated. The dispersion morphology of nanoclays within the TPU matrix was examined using transmission electron microscopy (TEM). It was found that the nanoclays exhibited a well-dispersed and intercalated structure, which contributed to the improved mechanical properties of the TPUNC scaffolds. Mechanical testing revealed that the addition of nanoclays significantly enhanced the compressive strength and elastic resilience of the TPUNC scaffolds. Cell viability and proliferation assays were conducted using MG63 cells cultured on the TPUNC scaffolds. The incorporation of nanoclays did not adversely affect cell viability, as evidenced by the comparable cell numbers between nanoclay-filled and unfilled TPU scaffolds. The presence of nanoclays within the TPUNC scaffolds did not disrupt cell adhesion or proliferation. The incorporation of nanoclays improved the dispersion morphology, enhanced mechanical performance, and maintained excellent biocompatibility. These findings suggest that TPUNC composites have great potential for tissue engineering applications, providing a versatile and promising scaffold material for regenerative medicine.
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Affiliation(s)
- Tie Geng
- Henan Provincial Engineering Research Centre of Automotive Composite Materials, School of Mechanical & Electrical Engineering, Henan University of Technology, Zhengzhou 450052, China; (T.G.); (H.-C.X.); (L.W.); (Y.-G.G.)
| | - Han-Chi Xiao
- Henan Provincial Engineering Research Centre of Automotive Composite Materials, School of Mechanical & Electrical Engineering, Henan University of Technology, Zhengzhou 450052, China; (T.G.); (H.-C.X.); (L.W.); (Y.-G.G.)
| | - Xin-Chao Wang
- Henan Provincial Engineering Research Centre of Automotive Composite Materials, School of Mechanical & Electrical Engineering, Henan University of Technology, Zhengzhou 450052, China; (T.G.); (H.-C.X.); (L.W.); (Y.-G.G.)
| | - Chun-Tai Liu
- National Engineering Research Center for Advanced Polymer Processing Technologies, Zhengzhou University, Zhengzhou 450001, China;
| | - Lan Wu
- Henan Provincial Engineering Research Centre of Automotive Composite Materials, School of Mechanical & Electrical Engineering, Henan University of Technology, Zhengzhou 450052, China; (T.G.); (H.-C.X.); (L.W.); (Y.-G.G.)
| | - Yong-Gang Guo
- Henan Provincial Engineering Research Centre of Automotive Composite Materials, School of Mechanical & Electrical Engineering, Henan University of Technology, Zhengzhou 450052, China; (T.G.); (H.-C.X.); (L.W.); (Y.-G.G.)
| | - Bin-Bin Dong
- National Engineering Research Center for Advanced Polymer Processing Technologies, Zhengzhou University, Zhengzhou 450001, China;
| | - Lih-Sheng Turng
- Wisconsin Institute for Discovery, University of Wisconsin–Madison, Madison, WI 53706, USA
- Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI 53706, USA
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Petryk NM, Haas G, Vakil AU, Monroe MBB. Shape memory polymer foams with tunable interconnectivity using off-the-shelf foaming components. J Biomed Mater Res A 2022; 110:1422-1434. [PMID: 35319810 DOI: 10.1002/jbm.a.37383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 03/03/2022] [Accepted: 03/13/2022] [Indexed: 12/28/2022]
Abstract
The ability to easily and safety tune pore structures of gas-blown polyurethane shape memory polymer (SMP) foams could improve their outcomes as hemostatic dressings or tissue engineering scaffolds and enable overall commercialization efforts. Incorporating physical blowing agents into the polymer mix can be used to tune pore size and interconnectivity without altering foam chemistry. Enovate (HFC-254fa) is a commonly used physical blowing agent in gas-blown foams, but the Environmental Protection Agency (EPA) considers its use unacceptable because it is a hydrofluorocarbon that contributes to global warming. Here, off-the-shelf solvents accepted for use by the EPA, acetone, dimethyoxymethane (methylal), and methyl formate, were used as physical blowing agents by adding small volumes during foam fabrication. Increasing the physical blowing agent volume resulted in greater pore interconnectivity while maintaining SMP foam chemical and thermal properties. Pore size and interconnectivity also impacted cell and blood interactions with the foams. This work provides a safe and easy method for tuning SMP foam interconnectivity to aid in future commercialization efforts in a range of potential biomedical applications.
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Affiliation(s)
- Natalie Marie Petryk
- Department of Biomedical and Chemical Engineering, BioInspired Syracuse, Syracuse University, Syracuse, New York, 13244, USA
| | - Grace Haas
- Department of Biomedical and Chemical Engineering, BioInspired Syracuse, Syracuse University, Syracuse, New York, 13244, USA
| | - Anand Utpal Vakil
- Department of Biomedical and Chemical Engineering, BioInspired Syracuse, Syracuse University, Syracuse, New York, 13244, USA
| | - Mary Beth Browning Monroe
- Department of Biomedical and Chemical Engineering, BioInspired Syracuse, Syracuse University, Syracuse, New York, 13244, USA
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Beaman HT, Shepherd E, Satalin J, Blair S, Ramcharran H, Serinelli S, Gitto L, Dong KS, Fikhman D, Nieman G, Schauer SG, Monroe MBB. Hemostatic shape memory polymer foams with improved survival in a lethal traumatic hemorrhage model. Acta Biomater 2022; 137:112-123. [PMID: 34655799 DOI: 10.1016/j.actbio.2021.10.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 11/01/2022]
Abstract
Although there are many hemostatic agents available for use on the battlefield, uncontrolled hemorrhage is still the primary cause of preventable death. Current hemostatic dressings include QuikClot® Combat Gauze (QCCG) and XStat®, which have inadequate success in reducing mortality. To address this need, a new hemostatic material was developed using shape memory polymer (SMP) foams, which demonstrate biocompatibility, rapid clotting, and shape recovery to fill the wound site. SMP foam hemostatic efficacy was examined in a lethal, noncompressible porcine liver injury model over 6 h following injury. Wounds were packed with SMP foams, XStat, or QCCG and compared in terms of time to bleeding cessation, total blood loss, and animal survival. The hemostatic material properties and in vitro blood interactions were also characterized. SMP foams decreased blood loss and active bleeding time in comparison with XStat and QCCG. Most importantly, SMP foams increased the 6 h survival rate by 50% and 37% (vs. XStat and QCCG, respectively) with significant increases in survival times. Based upon in vitro characterizations, this result is attributed to the low stiffness and shape filling capabilities of SMP foams. This study demonstrates that SMP foams have promise for improving upon current clinically available hemostatic dressings and that hemostatic material properties are important to consider in designing devices for noncompressible bleeding control. STATEMENT OF SIGNIFICANCE: Uncontrolled hemorrhage is the leading cause of preventable death on the battlefield, and it accounts for approximately 1.5 million deaths each year. New biomaterials are required for improved hemorrhage control, particularly in noncompressible wounds in the torso. Here, we compared shape memory polymer (SMP) foams with two clinical dressings, QuikClot Combat Gauze and XStat, in a pig model of lethal liver injury. SMP foam treatment reduced bleeding times and blood loss and significantly improved animal survival. After further material characterization, we determined that the improved outcomes with SMP foams are likely due to their low stiffness and controlled shape change after implantation, which enabled their delivery to the liver injuries without inducing further wound tearing. Overall, SMP foams provide a promising option for hemorrhage control.
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Vakil AU, Petryk NM, Shepherd E, Monroe MBB. Biostable Shape Memory Polymer Foams for Smart Biomaterial Applications. Polymers (Basel) 2021; 13:polym13234084. [PMID: 34883587 PMCID: PMC8658902 DOI: 10.3390/polym13234084] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/16/2022] Open
Abstract
Polyurethane foams provide a wide range of applications as a biomaterial system due to the ability to tune their physical, chemical, and biological properties to meet the requirements of the intended applications. Another key parameter that determines the usability of this biomaterial is its degradability under body conditions. Several current approaches focus on slowing the degradation rate for applications that require the implant to be present for a longer time frame (over 100 days). Here, biostable shape memory polymer (SMP) foams were synthesized with added ether-containing monomers to tune the degradation rates. The physical, thermal and shape memory properties of these foams were characterized along with their cytocompatibility and blood interactions. Degradation profiles were assessed in vitro in oxidative (3% H2O2; real-time) and hydrolytic media (0.1 M NaOH; accelerated) at 37 °C. The resulting foams had tunable degradation rates, with up 15% mass remaining after 108 days, and controlled erosion profiles. These easy-to-use, shape-filling SMP foams have the potential for various biomaterial applications where longer-term stability without the need for implant removal is desired.
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Vakil A, Petryk NM, Shepherd E, Beaman HT, Ganesh PS, Dong KS, Monroe MBB. Shape Memory Polymer Foams with Tunable Degradation Profiles. ACS APPLIED BIO MATERIALS 2021; 4:6769-6779. [PMID: 34568773 PMCID: PMC8456454 DOI: 10.1021/acsabm.1c00516] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/03/2021] [Indexed: 11/29/2022]
Abstract
Uncontrolled hemorrhage is the leading cause of preventable death on the battlefield and results in ∼1.5 million deaths each year. The primary current treatment options are gauze and/or tourniquets, which are ineffective for up to 80% of wounds. Additionally, most hemostatic materials must be removed from the patient within <12 h, which limits their applicability in remote scenarios and can cause additional bleeding upon removal. Here, degradable shape memory polymer (SMP) foams were synthesized to overcome these limitations. SMP foams were modified with oxidatively labile ether groups and hydrolytically labile ester groups to degrade after implantation. Foam physical, thermal, and shape memory properties were assessed along with cytocompatibility and blood interactions. Degradation profiles were obtained in vitro in oxidative and hydrolytic media (3% H2O2 (oxidation) and 0.1 M NaOH (hydrolysis) at 37 °C). The resulting foams had tunable, clinically relevant degradation rates, with complete mass loss within 30-60 days. These SMP foams have potential to provide an easy-to-use, shape-filling hemostatic dressing that can be left in place during traumatic wound healing with future potential use in regenerative medicine applications.
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Affiliation(s)
- Anand
Utpal Vakil
- Department of Biomedical
and Chemical Engineering, Syracuse Biomaterials Institute, and BioInspired
Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, New York 13244, United States
| | - Natalie Marie Petryk
- Department of Biomedical
and Chemical Engineering, Syracuse Biomaterials Institute, and BioInspired
Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, New York 13244, United States
| | - Ellen Shepherd
- Department of Biomedical
and Chemical Engineering, Syracuse Biomaterials Institute, and BioInspired
Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, New York 13244, United States
| | - Henry T. Beaman
- Department of Biomedical
and Chemical Engineering, Syracuse Biomaterials Institute, and BioInspired
Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, New York 13244, United States
| | - Priya S. Ganesh
- Department of Biomedical
and Chemical Engineering, Syracuse Biomaterials Institute, and BioInspired
Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, New York 13244, United States
| | - Katheryn S. Dong
- Department of Biomedical
and Chemical Engineering, Syracuse Biomaterials Institute, and BioInspired
Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, New York 13244, United States
| | - Mary Beth B. Monroe
- Department of Biomedical
and Chemical Engineering, Syracuse Biomaterials Institute, and BioInspired
Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, New York 13244, United States
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Xiao R, Huang WM. Heating/Solvent Responsive Shape-Memory Polymers for Implant Biomedical Devices in Minimally Invasive Surgery: Current Status and Challenge. Macromol Biosci 2020; 20:e2000108. [PMID: 32567193 DOI: 10.1002/mabi.202000108] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/03/2020] [Indexed: 12/16/2022]
Abstract
This review is about the fundamentals and practical issues in applying both heating and solvent responsive shape memory polymers (SMPs) for implant biomedical devices via minimally invasive surgery. After revealing the general requirements in the design of biomedical devices based on SMPs and the fundamentals for the shape-memory effect in SMPs, the underlying mechanisms, characterization methods, and several representative biomedical applications, including vascular stents, tissue scaffolds, occlusion devices, drug delivery systems, and the current R&D status of them, are discussed. The new opportunities arising from emerging technologies, such as 3D printing, and new materials, such as vitrimer, are also highlighted. Finally, the major challenge that limits the practical clinical applications of SMPs at present is addressed.
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Affiliation(s)
- Rui Xiao
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027, China
| | - Wei Min Huang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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Jang LK, Fletcher GK, Monroe MBB, Maitland DJ. Biodegradable shape memory polymer foams with appropriate thermal properties for hemostatic applications. J Biomed Mater Res A 2020; 108:1281-1294. [PMID: 32061006 PMCID: PMC7364661 DOI: 10.1002/jbm.a.36901] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 02/08/2020] [Accepted: 02/10/2020] [Indexed: 11/11/2022]
Abstract
Shape memory polymer (SMP) foams are a promising material for hemostatic dressings due to their biocompatibility, high surface area, excellent shape recovery, and ability to quickly initiate blood clotting. Biodegradable SMP foams could eliminate the need for a secondary removal procedure of hemostatic material from the patients' wound, further facilitating wound healing. In this study, we developed hydrolytically and oxidatively biodegradable SMP foams by reacting polyols (triethanolamine or glycerol) with 6-aminocaproic acid or glycine to generate foaming monomers with degradable ester bonds. These monomers were used in foam synthesis to provide highly crosslinked SMP foam structures. The ester-containing foams showed clinically relevant thermal properties that were comparable to controls and excellent shape recovery within eight min. Triethanolamine-based ester-containing foams showed interconnected porous structure along with increased mechanical strength. Faster hydrolytic and oxidative biodegradation rates were achieved in ester-containing foams in comparison to controls. These biodegradable SMP foams with clinically applicable thermal properties possess great potential as an effective hemostatic device for use in hospitals or on battlefields.
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Affiliation(s)
- Lindy K. Jang
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas
| | - Grace K. Fletcher
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas
| | - Mary Beth B. Monroe
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York
| | - Duncan J. Maitland
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas
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Monroe MBB, Easley AD, Grant K, Fletcher GK, Boyer C, Maitland DJ. Multifunctional Shape-Memory Polymer Foams with Bio-inspired Antimicrobials. Chemphyschem 2017; 19:1999-2008. [PMID: 29282877 DOI: 10.1002/cphc.201701015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Indexed: 11/09/2022]
Abstract
Despite a number of clinically available hemostats, uncontrolled bleeding is the primary cause of trauma-related death. Shape-memory polymer (SMP) foams have a number of desirable properties for use as hemostats, including shape recovery to enable delivery into bleed sites, biocompatibility, and rapid blood clotting. To expand upon this material system, the current work aims to incorporate phenolic acids, which are honey-based antimicrobial agents, into SMP foams. We showed that cinnamic acid (CA) can be utilized as a monomer in SMP synthesis to provide foams with comparable pore structure and retained cytocompatibility. The addition of CA enabled tuning of thermal and shape-memory properties within clinically relevant ranges. Furthermore, the modified foams demonstrated initial and sustained antimicrobial effects against gram-positive and gram-negative bacteria. These multifunctional scaffolds demonstrate potential for use as hemostats to improve upon current hemorrhage treatments and provide a new tool in tuning the biological and material properties of SMP foams.
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Affiliation(s)
- Mary Beth Browning Monroe
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843-3120, USA
| | - Alexandra D Easley
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843-3120, USA
| | - Katie Grant
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843-3120, USA
| | - Grace K Fletcher
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843-3120, USA
| | - Calla Boyer
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843-3120, USA
| | - Duncan J Maitland
- Department of Biomedical Engineering, Texas A&M University, 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843-3120, USA
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Peterson GI, Dobrynin AV, Becker ML. Biodegradable Shape Memory Polymers in Medicine. Adv Healthc Mater 2017; 6. [PMID: 28941154 DOI: 10.1002/adhm.201700694] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/04/2017] [Indexed: 01/13/2023]
Abstract
Shape memory materials have emerged as an important class of materials in medicine due to their ability to change shape in response to a specific stimulus, enabling the simplification of medical procedures, use of minimally invasive techniques, and access to new treatment modalities. Shape memory polymers, in particular, are well suited for such applications given their excellent shape memory performance, tunable materials properties, minimal toxicity, and potential for biodegradation and resorption. This review provides an overview of biodegradable shape memory polymers that have been used in medical applications. The majority of biodegradable shape memory polymers are based on thermally responsive polyesters or polymers that contain hydrolyzable ester linkages. These materials have been targeted for use in applications pertaining to embolization, drug delivery, stents, tissue engineering, and wound closure. The development of biodegradable shape memory polymers with unique properties or responsiveness to novel stimuli has the potential to facilitate the optimization and development of new medical applications.
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Affiliation(s)
- Gregory I. Peterson
- The University of Akron Department of Polymer Science Akron OH 44325‐3909 USA
| | - Andrey V. Dobrynin
- The University of Akron Department of Polymer Science Akron OH 44325‐3909 USA
| | - Matthew L. Becker
- The University of Akron Department of Polymer Science Akron OH 44325‐3909 USA
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