1
|
Górecka Ż, Idaszek J, Heljak M, Martinez DC, Choińska E, Kulas Z, Święszkowski W. Indocyanine green and iohexol loaded hydroxyapatite in poly(L-lactide-co-caprolactone)-based composite for bimodal near-infrared fluorescence- and X-ray-based imaging. J Biomed Mater Res B Appl Biomater 2024; 112:e35313. [PMID: 37596854 DOI: 10.1002/jbm.b.35313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 07/19/2023] [Accepted: 07/31/2023] [Indexed: 08/20/2023]
Abstract
This study aimed to develop material for multimodal imaging by means of X-ray and near-infrared containing FDA- and EMA-approved iohexol and indocyanine green (ICG). The mentioned contrast agents (CAs) are hydrophilic and amphiphilic, respectively, which creates difficulties in fabrication of functional polymeric composites for fiducial markers (FMs) with usage thereof. Therefore, this study exploited for the first time the possibility of enhancing the radiopacity and introduction of the NIR fluorescence of FMs by adsorption of the CAs on hydroxyapatite (HAp) nanoparticles. The particles were embedded in the poly(L-lactide-co-caprolactone) (P[LAcoCL]) matrix resulting in the composite material for bimodal near-infrared fluorescence- and X-ray-based imaging. The applied method of material preparation provided homogenous distribution of both CAs with high iohexol loading efficiency and improved fluorescence signal due to hindered ICG aggregation. The material possessed profound contrasting properties for both imaging modalities. Its stability was evaluated during in vitro experiments in phosphate-buffered saline (PBS) and foetal bovine serum (FBS) solutions. The addition of HAp nanoparticles had significant effect on the fluorescence signal. The X-ray radiopacity was stable within minimum 11 weeks, even though the addition of ICG contributed to a faster release of iohexol. The stiffness of the material was not affected by iohexol or ICG, but incorporation of HAp nanoparticles elevated the values of bending modulus by approximately 70%. Moreover, the performed cell study revealed that all tested materials were not cytotoxic. Thus, the developed material can be successfully used for fabrication of FMs.
Collapse
Affiliation(s)
- Żaneta Górecka
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland
- Centre for Advanced Materials and Technologies CEZAMAT, Warsaw University of Technology, Warsaw, Poland
| | - Joanna Idaszek
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland
| | - Marcin Heljak
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland
| | - Diana C Martinez
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland
| | - Emilia Choińska
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland
| | - Zbigniew Kulas
- Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Wojciech Święszkowski
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland
| |
Collapse
|
2
|
Górecka Ż, Grzelecki D, Paskal W, Choińska E, Gilewicz J, Wrzesień R, Macherzyński W, Tracz M, Budzińska-Wrzesień E, Bedyńska M, Kopka M, Jackowska-Tracz A, Świątek-Najwer E, Włodarski PK, Jaworowski J, Święszkowski W. Biodegradable Fiducial Markers for Bimodal Near-Infrared Fluorescence- and X-ray-Based Imaging. ACS Biomater Sci Eng 2022; 8:859-870. [PMID: 35020357 DOI: 10.1021/acsbiomaterials.1c01259] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This study aimed to evaluate, for the first time, implantable, biodegradable fiducial markers (FMs), which were designed for bimodal, near-infrared fluorescence-based (NIRF) and X-ray-based imaging. The developed FMs had poly(l-lactide-co-caprolactone)-based core-shell structures made of radiopaque (core) and fluorescent (shell) composites with a poly(l-lactide-co-caprolactone) matrix. The approved for human use contrast agents were utilized as fillers. Indocyanine green was applied to the shell material, whereas in the core materials, iohexol and barium sulfate were compared. Moreover, the possibility of tailoring the stability of the properties of the core materials by the addition of hydroxyapatite (HAp) was examined. The performed in situ (porcine tissue) and in vivo experiment (rat model) confirmed that the developed FMs possessed pronounced contrasting properties in NIRF and X-ray imaging. The presence of HAp improved the radiopacity of FMs at the initial state. It was also proved that, in iohexol-containing FMs, the presence of HAp slightly decreased the stability of contrasting properties, while in BaSO4-containing ones, changes were less pronounced. A comprehensive material analysis explaining the differences in the stability of the contrasting properties was also presented. The tissue response around the FMs with composite cores was comparable to that of the FMs with a pristine polymeric core. The developed composite FMs did not cause serious adverse effects on the surrounding tissues even when irradiated in vivo. The developed FMs ensured good visibility for NIRF image-supported tumor surgery and the following X-ray image-guided radiotherapy. Moreover, this study replenishes a scanty report regarding similar biodegradable composite materials with a high potential for application.
Collapse
Affiliation(s)
- Żaneta Górecka
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Woloska Str., 02-507 Warsaw, Poland.,Centre for Advanced Materials and Technologies CEZAMAT, Warsaw University of Technology, 02-822 Warsaw, Poland
| | - Dariusz Grzelecki
- Department of Applied Pharmacy, Medical University of Warsaw, 02-097 Warsaw, Poland.,Department of Orthopedics and Rheumoorthopedics, Professor Adam Gruca Teaching Hospital, Centre of Postgraduate Medical Education, 05-400 Otwock, Poland
| | - Wiktor Paskal
- Centre for Preclinical Research, The Department of Methodology, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Emilia Choińska
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Woloska Str., 02-507 Warsaw, Poland
| | - Joanna Gilewicz
- Department of Applied Pharmacy, Medical University of Warsaw, 02-097 Warsaw, Poland
| | - Robert Wrzesień
- Central Laboratory of Experimental Animal, Medical University of Warsaw, 02-097 Warsaw, Poland
| | - Wojciech Macherzyński
- Faculty of Microsystem Electronics and Photonics, Wroclaw University of Science and Technology, 50-372 Wroclaw, Poland
| | - Michał Tracz
- Institute of Veterinary Medicine, Department of Food Hygiene and Public Health Protection, Warsaw University of Life Sciences, 02-776 Warsaw, Poland
| | | | - Maria Bedyńska
- Department of Applied Pharmacy, Medical University of Warsaw, 02-097 Warsaw, Poland
| | - Michał Kopka
- Centre for Preclinical Research, The Department of Methodology, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Agnieszka Jackowska-Tracz
- Institute of Veterinary Medicine, Department of Food Hygiene and Public Health Protection, Warsaw University of Life Sciences, 02-776 Warsaw, Poland
| | - Ewelina Świątek-Najwer
- Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, 50-371 Wroclaw, Poland
| | - Paweł K Włodarski
- Centre for Preclinical Research, The Department of Methodology, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Janusz Jaworowski
- Department of Applied Pharmacy, Medical University of Warsaw, 02-097 Warsaw, Poland
| | - Wojciech Święszkowski
- Division of Materials Design, Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Woloska Str., 02-507 Warsaw, Poland
| |
Collapse
|
3
|
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.
Collapse
|
4
|
Programmable Stimuli-Responsive Actuators for Complex Motions in Soft Robotics: Concept, Design and Challenges. ACTUATORS 2020. [DOI: 10.3390/act9040131] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
During the last years, great progress was made in material science in terms of concept, design and fabrication of new composite materials with conferred properties and desired functionalities. The scientific community paid particular interest to active soft materials, such as soft actuators, for their potential as transducers responding to various stimuli aiming to produce mechanical work. Inspired by this, materials engineers today are developing multidisciplinary approaches to produce new active matters, focusing on the kinematics allowed by the material itself more than on the possibilities offered by its design. Traditionally, more complex motions beyond pure elongation and bending are addressed by the robotics community. The present review targets encompassing and rationalizing a framework which will help a wider scientific audience to understand, sort and design future soft actuators and methods enabling complex motions. Special attention is devoted to recent progress in developing innovative stimulus-responsive materials and approaches for complex motion programming for soft robotics. In this context, a challenging overview of the new materials as well as their classification and comparison (performances and characteristics) are proposed. In addition, the great potential of soft transducers are outlined in terms of kinematic capabilities, illustrated by the related application. Guidelines are provided to design actuators and to integrate asymmetry enabling motions along any of the six basic degrees of freedom (translations and rotations), and strategies towards the programming of more complex motions are discussed. As a final note, a series of manufacturing methods are described and compared, from molding to 3D and 4D printing. The review ends with a Perspectives section, from material science and microrobotic points of view, on the soft materials’ future and close future challenges to be overcome.
Collapse
|
5
|
Sarvari R, Keyhanvar P, Agbolaghi S, Gholami Farashah MS, Sadrhaghighi A, Nouri M, Roshangar L. Shape-memory materials and their clinical applications. INT J POLYM MATER PO 2020. [DOI: 10.1080/00914037.2020.1833010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Raana Sarvari
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Stem Cell And Regenerative Medicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Peyman Keyhanvar
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Nanotechnology, School of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
- Convergence of Knowledge, Technology and Society Network (CKTSN), Universal Scientific Education and Research Network (USERN), Tabriz, Iran
- ARTAN110 Startup Accelerator, Tabriz, Iran
| | - Samira Agbolaghi
- Chemical Engineering Department, Faculty of Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran
| | | | - Amirhouman Sadrhaghighi
- Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Nouri
- Department of Reproductive Biology, Faculty of Advanced Medical Sciences, University of Medical Sciences, Tabriz, Iran
| | - Laila Roshangar
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| |
Collapse
|
6
|
Weems AC, Pérez-Madrigal MM, Arno MC, Dove AP. 3D Printing for the Clinic: Examining Contemporary Polymeric Biomaterials and Their Clinical Utility. Biomacromolecules 2020; 21:1037-1059. [PMID: 32058702 DOI: 10.1021/acs.biomac.9b01539] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The advent of additive manufacturing offered the potential to revolutionize clinical medicine, particularly with patient-specific implants across a range of tissue types. However, to date, there are very few examples of polymers being used for additive processes in clinical settings. The state of the art with regards to 3D printable polymeric materials being exploited to produce novel clinically relevant implants is discussed here. We focus on the recent advances in the development of implantable, polymeric medical devices and tissue scaffolds without diverging extensively into bioprinting. By introducing the major 3D printing techniques along with current advancements in biomaterials, we hope to provide insight into how these fields may continue to advance while simultaneously reviewing the ongoing work in the field.
Collapse
Affiliation(s)
- Andrew C Weems
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, U.K
| | | | - Maria C Arno
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, U.K
| | - Andrew P Dove
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, U.K
| |
Collapse
|
7
|
Jose S, George JJ, Siengchin S, Parameswaranpillai J. Introduction to Shape-Memory Polymers, Polymer Blends and Composites: State of the Art, Opportunities, New Challenges and Future Outlook. ADVANCED STRUCTURED MATERIALS 2020. [DOI: 10.1007/978-981-13-8574-2_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
8
|
Weems AC, Carrow JK, Gaharwar AK, Maitland DJ. Improving the Oxidative Stability of Shape Memory Polyurethanes Containing Tertiary Amines by the Presence of Isocyanurate Triols. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01925] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
9
|
Fluorescent shape-memory hyperbranched polyurethanes: Synthesis, characterization and evaluation of cytotoxicity. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2018.09.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
10
|
Weems AC, Li W, Maitland DJ, Calle LM. Polyurethane Microparticles for Stimuli Response and Reduced Oxidative Degradation in Highly Porous Shape Memory Polymers. ACS APPLIED MATERIALS & INTERFACES 2018; 10:32998-33009. [PMID: 30184426 PMCID: PMC7433764 DOI: 10.1021/acsami.8b11082] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Shape memory polymers (SMPs) have been found to be promising biomaterials for a variety of medical applications; however, the clinical translation of such technology is dependent on tailorable properties such as gravimetric changes in degradation environments. For SMPs synthesized from amino-alcohols, oxidation resulting in rapid mass loss may be problematic in terms of loss of material functionality as well as toxicity and cytocompatibility concerns. Control of gravimetric changes was achieved through the incorporation of small molecule antioxidants, either directly into the polymer matrix or included in microparticles to form a SMP composite material. With direct incorporation of small molecule phenolic antioxidant 2,2'-methylenebis(6- tert-butyl)-methylphenol (Methyl), SMPs displayed reduce strain recovery by more than 50% (Methyl) and increase elastic modulus from approximately 1.4 to 2.3 MPa, at the expense of the strain to failure being reduced from 45% to 32%. Importantly, such changes could not ensure retention of the antioxidants and therefore did not increase oxidative stability beyond 15 days in accelerated oxidative conditions (equivalent to approximately 800 days in porcine aneurysms) in all cases except for the inclusion of a hindered amine that capped network growth, which also resulted in shape memory reduction (only 80% recoverable strain achieved). However, the inclusion of antioxidants in microparticles was found to produce materials with similar thermomechanical ( Tg migration below 1.0 °C) and shape recovery of 100%, while increasing oxidative resistance compared to controls (oxidation onset was delayed by 3 days and material lifespan increased to approximately 20-22 days in accelerated oxidative solution or beyond 1000 days in the porcine aneurysm). The microparticle composite SMPs also act as a platform for environmental sensing, such as pH-dependent fluorescence shifts and payload release, as demonstrated by fluorescent dye studies using phloxine B and nile blue chloride and the release of antioxidants over a 3 week period. The use of polyurethane-urea microparticles in porous SMPs is demonstrated to increase biostability of the materials, by approximately 25%, and ultimately extend their lifespan for use in aneurysm occlusion as determined through calculated in vivo degradation rates corresponding to a porcine aneurysm environment.
Collapse
Affiliation(s)
- A. C. Weems
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77840, United States
| | - W. Li
- Corrosion Technology Laboratory, NASA, Kennedy Space Center, Florida 32899, United States
| | - D. J. Maitland
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77840, United States
| | - L. M. Calle
- Corrosion Technology Laboratory, NASA, Kennedy Space Center, Florida 32899, United States
| |
Collapse
|
11
|
Toncheva A, Khelifa F, Paint Y, Voué M, Lambert P, Dubois P, Raquez JM. Fast IR-Actuated Shape-Memory Polymers Using in Situ Silver Nanoparticle-Grafted Cellulose Nanocrystals. ACS APPLIED MATERIALS & INTERFACES 2018; 10:29933-29942. [PMID: 30092638 DOI: 10.1021/acsami.8b10159] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In recent years, shape-memory polymers (SMPs) have gained a key position in the realm of actuating applications from daily life products to biomedical and aeronautic devices. Most of these SMPs rely mainly on shape changes upon direct heat exposure or after stimulus conversion (e.g., magnetic field and light) to heat, but this concept remains significantly limited when both remote control and fine actuation are demanded. In the present study, we propose to design plasmonic silver nanoparticles (AgNPs) grafted onto cellulose nanocrystals (CNCs) as an efficient plasmonic system for fast and remote actuation. Such CNC- g-AgNPs "nanorod-like" structures thereby allowed for a long-distance and strong coupling plasmonic effect between the AgNPs along the CNC axis, thus ensuring a fast photothermal shape-recovery effect upon IR light illumination. To demonstrate the fast and remote actuation promoted by these structures, we incorporated them at low loading (1 wt %) into poly(ε-caprolactone) (PCL)-based networks with shape-memory properties. These polymer matrix networks were practically designed from biocompatible PCL oligomers end-functionalized with maleimide and furan moieties in the melt on the basis of thermoreversible Diels-Alder reactions. The as-produced materials could find application in the realm of soft robotics for remote object transportation or as smart biomaterials such as self-tightening knots with antibacterial properties related to the presence of the AgNPs.
Collapse
Affiliation(s)
- Antoniya Toncheva
- Laboratory of Polymeric and Composite Materials , University of Mons , 23 Place du Parc , Mons 7000 , Belgium
- Laboratory of Bioactive Polymers, Institute of Polymers , Bulgarian Academy of Sciences , 103A Academik G. Bonchev Street , Sofia 1113 , Bulgaria
| | - Farid Khelifa
- Laboratory of Polymeric and Composite Materials , University of Mons , 23 Place du Parc , Mons 7000 , Belgium
| | - Yoann Paint
- Analysis and Characterization Unit , Materia Nova , 1 Avenue Copernic , Mons 7000 , Belgium
| | - Michel Voué
- Materials Physics and Optics , University of Mons , 20 Place du Parc , Mons 7000 , Belgium
| | - Pierre Lambert
- BioElectro and Mechanical Systems Department , Free University of Brussels , 50 Avenue F.D. Roosevelt , Brussels 1050 , Belgium
| | - Philippe Dubois
- Laboratory of Polymeric and Composite Materials , University of Mons , 23 Place du Parc , Mons 7000 , Belgium
| | - Jean-Marie Raquez
- Laboratory of Polymeric and Composite Materials , University of Mons , 23 Place du Parc , Mons 7000 , Belgium
| |
Collapse
|
12
|
|
13
|
Lian H, Chang W, Liang Q, Hu C, Wang R, Zu L, Liu Y. A shape memory polyurethane based ionic polymer–carbon nanotube composite. RSC Adv 2017. [DOI: 10.1039/c7ra07476j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The blocking force of 25% GO–IPU is 5 times that of neat IPU.
Collapse
Affiliation(s)
- Huiqin Lian
- Beijing Key Lab of Special Elastomer Composite Materials
- College of Materials Science and Engineering
- Beijing Institute of Petrochemical Technology
- Beijing 102617
- China
| | - Wei Chang
- Beijing Key Lab of Special Elastomer Composite Materials
- College of Materials Science and Engineering
- Beijing Institute of Petrochemical Technology
- Beijing 102617
- China
| | - Qian Liang
- Beijing Key Lab of Special Elastomer Composite Materials
- College of Materials Science and Engineering
- Beijing Institute of Petrochemical Technology
- Beijing 102617
- China
| | - Chufeng Hu
- Beijing Key Lab of Special Elastomer Composite Materials
- College of Materials Science and Engineering
- Beijing Institute of Petrochemical Technology
- Beijing 102617
- China
| | - Rui Wang
- Beijing Key Lab of Special Elastomer Composite Materials
- College of Materials Science and Engineering
- Beijing Institute of Petrochemical Technology
- Beijing 102617
- China
| | - Lei Zu
- Beijing Key Lab of Special Elastomer Composite Materials
- College of Materials Science and Engineering
- Beijing Institute of Petrochemical Technology
- Beijing 102617
- China
| | - Yang Liu
- Beijing Key Lab of Special Elastomer Composite Materials
- College of Materials Science and Engineering
- Beijing Institute of Petrochemical Technology
- Beijing 102617
- China
| |
Collapse
|