1
|
Indrakumar S, Dash TK, Mishra V, Tandon B, Chatterjee K. Silk Fibroin and Its Nanocomposites for Wound Care: A Comprehensive Review. ACS POLYMERS AU 2024; 4:168-188. [PMID: 38882037 PMCID: PMC11177305 DOI: 10.1021/acspolymersau.3c00050] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 06/18/2024]
Abstract
For most individuals, wound healing is a highly organized, straightforward process, wherein the body transitions through different phases in a timely manner. However, there are instances where external intervention becomes necessary to support and facilitate different phases of the body's innate healing mechanism. Furthermore, in developing countries, the cost of the intervention significantly impacts access to treatment options as affordability becomes a determining factor. This is particularly true in cases of long-term wound treatment and management, such as chronic wounds and infections. Silk fibroin (SF) and its nanocomposites have emerged as promising biomaterials with potent wound-healing activity. Driven by this motivation, this Review presents a critical overview of the recent advancements in different aspects of wound care using SF and SF-based nanocomposites. In this context, we explore various formats of hemostats and assess their suitability for different bleeding situations. The subsequent sections discuss the primary causes of nonhealing wounds, i.e., prolonged inflammation and infections. Herein, different treatment strategies to achieve immunomodulatory and antibacterial properties in a wound dressing were reviewed. Despite exhibiting excellent pro-healing properties, few silk-based products reach the market. This Review concludes by highlighting the bottlenecks in translating silk-based products into the market and the prospects for the future.
Collapse
Affiliation(s)
- Sushma Indrakumar
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Tapan Kumar Dash
- Fibroheal Woundcare Pvt. Ltd., Yelahanka New Town, Bangalore 560064, India
| | - Vivek Mishra
- Fibroheal Woundcare Pvt. Ltd., Yelahanka New Town, Bangalore 560064, India
| | - Bharat Tandon
- Fibroheal Woundcare Pvt. Ltd., Yelahanka New Town, Bangalore 560064, India
| | - Kaushik Chatterjee
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
| |
Collapse
|
2
|
Tan G, Jia T, Qi Z, Lu S. Regenerated Fiber's Ideal Target: Comparable to Natural Fiber. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1834. [PMID: 38673192 PMCID: PMC11050933 DOI: 10.3390/ma17081834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/12/2024] [Accepted: 04/13/2024] [Indexed: 04/28/2024]
Abstract
The toughness of silk naturally obtained from spiders and silkworms exceeds that of all other natural and man-made fibers. These insects transform aqueous protein feedstocks into mechanically specialized materials, which represents an engineering phenomenon that has developed over millions of years of natural evolution. Silkworms have become a new research hotspot due to the difficulties in collecting spider silk and other challenges. According to continuous research on the natural spinning process of the silkworm, it is possible to divide the main aspects of bionic spinning into two main segments: the solvent and behavior. This work focuses on the various methods currently used for the spinning of artificial silk fibers to replicate natural silk fibers, providing new insights based on changes in the fiber properties and production processes over time.
Collapse
Affiliation(s)
| | | | | | - Shenzhou Lu
- National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China; (G.T.); (T.J.); (Z.Q.)
| |
Collapse
|
3
|
Shao H, Wu X, Xiao Y, Yang Y, Ma J, Zhou Y, Chen W, Qin S, Yang J, Wang R, Li H. Recent research advances on polysaccharide-, peptide-, and protein-based hemostatic materials: A review. Int J Biol Macromol 2024; 261:129752. [PMID: 38280705 DOI: 10.1016/j.ijbiomac.2024.129752] [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: 07/18/2023] [Revised: 11/05/2023] [Accepted: 01/23/2024] [Indexed: 01/29/2024]
Abstract
Hemorrhage is a potentially life-threatening emergency that can occur at any time or place. Whether traumatic, congenital, surgical, disease-related, or drug-induced, bleeding can lead to severe complications or death. Therefore, the development of efficient hemostatic materials is critical. However, the results and prognosis demonstrated by clinical means of hemostasis do not reach expectations. With the development of technology, novel hemostatic materials have been developed from polysaccharides (chitosan, hyaluronic acid, alginate, cellulose, cyclodextrins, starch, dextran, and carrageenan), peptides (self-assembling peptides), and proteins (silk fibroin, collagen, gelatin, keratin, and thrombin). These new materials exhibit high hemostatic efficacy due to the enhancement or interaction of various hemostatic mechanisms. The main forms include adhesives, sealants, bandages, hemostatic powders, and hemostatic sponges. This article introduces the clotting process and principles of hemostatic methods and reviews the research on polysaccharide-, peptide-, and protein-based hemostatic materials in the last five years. The design ideas and hemostatic principles of polysaccharide-, peptide-, and protein-based hemostatic materials are mainly introduced. Finally, we summarize material designs, advantages, disadvantages, and challenges regarding hemostatic materials.
Collapse
Affiliation(s)
- Hanjie Shao
- Ningbo Medical Center Li Huili Hospital, Health Science Center, Ningbo University, Ningbo 315000, PR China; Zhejiang International Scientific and Technological Cooperative Base of Biomedical Materials and Technology, Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, PR China; Ningbo Cixi Institute of Biomedical Engineering, Ningbo 315300, PR China
| | - Xiang Wu
- Ningbo Medical Center Li Huili Hospital, Health Science Center, Ningbo University, Ningbo 315000, PR China; Zhejiang International Scientific and Technological Cooperative Base of Biomedical Materials and Technology, Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, PR China; Ningbo Cixi Institute of Biomedical Engineering, Ningbo 315300, PR China
| | - Ying Xiao
- Zhejiang International Scientific and Technological Cooperative Base of Biomedical Materials and Technology, Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, PR China; Ningbo Cixi Institute of Biomedical Engineering, Ningbo 315300, PR China
| | - Yanyu Yang
- Zhejiang International Scientific and Technological Cooperative Base of Biomedical Materials and Technology, Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, PR China; Ningbo Cixi Institute of Biomedical Engineering, Ningbo 315300, PR China
| | - Jingyun Ma
- Ningbo Institute of Innovation for Combined Medicine and Engineering, The Affiliated Li Huili Hospital, Ningbo University, Ningbo 315100, PR China
| | - Yang Zhou
- Ningbo Institute of Innovation for Combined Medicine and Engineering, The Affiliated Li Huili Hospital, Ningbo University, Ningbo 315100, PR China
| | - Wen Chen
- Ningbo Medical Center Li Huili Hospital, Health Science Center, Ningbo University, Ningbo 315000, PR China
| | - Shaoxia Qin
- Ningbo Medical Center Li Huili Hospital, Health Science Center, Ningbo University, Ningbo 315000, PR China
| | - Jiawei Yang
- Ningbo Medical Center Li Huili Hospital, Health Science Center, Ningbo University, Ningbo 315000, PR China
| | - Rong Wang
- Zhejiang International Scientific and Technological Cooperative Base of Biomedical Materials and Technology, Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, PR China; Ningbo Cixi Institute of Biomedical Engineering, Ningbo 315300, PR China.
| | - Hong Li
- Ningbo Medical Center Li Huili Hospital, Health Science Center, Ningbo University, Ningbo 315000, PR China.
| |
Collapse
|
4
|
Luo J, Wang J, Li Q, Xiong L, Xie R, Lan G, Ning LJ, Xie J, Hu E, Lu B. In situ generation of bioadhesives using dry tannic silk particles: a wet-adhesion strategy relying on removal of hydraulic layer over wet tissues for wound care. Int J Biol Macromol 2023; 250:126087. [PMID: 37536416 DOI: 10.1016/j.ijbiomac.2023.126087] [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: 05/31/2023] [Revised: 07/25/2023] [Accepted: 07/30/2023] [Indexed: 08/05/2023]
Abstract
Tissue adhesives have been widely used in biomedical applications. However, the presence of a hydrated layer on the surface of wet tissue severely hinders their adhesion capacities, resulting in ineffective wound treatment. To address this issue, a dry particle dressing (plas@SF/tann-hydro-pwd) capable of removing the hydrated layer and converting in situ to bioadhesives (plas@SF/tann-hydro-gel) was fabricated via simple physical mixing based on the hydrophobic-hydrogen bonding synergistic effect and Schiff-base reaction. It was found that the plas@SF/tann-hydro-gel bioadhesive, which was changed from plas@SF/tann-hydro-pwd dressing by adsorption of water, exhibited good wet adhesion to diverse biological tissues. In addition, the wet adhesion qualities of the plas@SF/tann-hydro-gel adhesive was studied under a variety of demanding conditions, including a wide range of temperatures, varying pH levels, highly concentrated salt solutions, and simulated fluids. Experiments on animals had showed that the adhesive plas@SF/tann-hydro-gel has superior wet adhesion qualities and superior wound healing properties compared to the commercial product Tegaderm™. This study develops a new wet-adhesion technique employing dry particle dressing to eliminate the hydrated layer over wet tissues for the in situ creation of gel bioadhesives for wound healing.
Collapse
Affiliation(s)
- Jinyang Luo
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Junsu Wang
- Chongqing Customs Technology Center, Chongqing 400044, China
| | - Qing Li
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Li Xiong
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Ruiqi Xie
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Guangqian Lan
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Liang-Ju Ning
- Department of Orthopedic Surgery and Orthopedic Research Institute, Laboratory of Stem Cell and Tissue Engineering, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, China
| | - Jing Xie
- Department of Stomatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Enling Hu
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China; School of Fashion and Textiles, The Hong Kong Polytechnic University, Hong Kong
| | - Bitao Lu
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China.
| |
Collapse
|
5
|
Wang JY, Chen LJ, Zhao X, Yan XP. Silk fibroin-based colorimetric microneedle patch for rapid detection of spoilage in packaged salmon samples. Food Chem 2023; 406:135039. [PMID: 36446279 DOI: 10.1016/j.foodchem.2022.135039] [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: 08/14/2022] [Revised: 10/28/2022] [Accepted: 11/20/2022] [Indexed: 11/24/2022]
Abstract
Spoiled salmon can cause foodborne diseases and severely affects human health. Herein, we report a pH-responsive colorimetric microneedle (MN) patch fabricated from bromothymol blue (BTB) and silk fibroin meth acryloyl (SilMA) (BTB/SilMA@MN patch) for sensing salmon spoilage. The needle tips of MN could penetrate food cling film and insert into fish to extract tissue fluids directly and transport the extracted fluids to the backing layer for color displaying. The color change of BTB/SilMA@MN patches depended on the pH variation resulting from the increase of total volatile basic nitrogen in salmon during storage. The color of MN patches changed from yellow to yellowish green and to final green, indicating salmon changed from fresh to medium fresh and then to putrefied, respectively. Salmon spoilage can be rapidly determined via naked eye recognition and also analyzed on a smartphone in a nondestructive way, allowing consumers to estimate food quality easily and reliably.
Collapse
Affiliation(s)
- Jiang-Yue Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China; Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Li-Jian Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China; Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Xu Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China; Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiu-Ping Yan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China; Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China.
| |
Collapse
|
6
|
Wu L, Ren K, Chen G, Wang H, Li H, Xu L. Hemostatic effect and safety evaluation of the absorbable macroporous polysaccharides composite hemostatic material prepared by a green fabrication approach. J Biomater Appl 2023; 37:1486-1496. [PMID: 36366726 DOI: 10.1177/08853282221139026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Carboxymethyl chitosan is widely used in the medical field such as wound healing and other medical fields. We previously fabricated the absorbable macroporous polysaccharides composite hemostatics (AMPCs) mainly composed of carboxymethyl chitosan which possess excellent hemostatic effect. To further elucidate the impact of CMCTs on the hemostatic effect and biosafety of AMPCs, carboxymethyl chitosan with different properties were used to prepare AMPCs. By comparing the physical and chemical properties, AMPCs performed high water absorption ability, especially Group 1 (swelling ratio reached 5792%), which facilitated the rapid formation of blood clots. It was confirmed by blood clotting index (BCI) and blood coagulation tests in vitro that Group 1 showed a slightly higher coagulation capacity than groups 2 and 3, which may be due to the positive charge on the surface of the cations in the salts attaches to the negative charge on the surface of the red blood cells, an electrostatic neutralization reaction occurs. The biosafety was a preliminary evaluation by implanted AMPCs into the back of Sprague-Dawley rats and the tissue was harvested after feeding for 28 days. The AMPCs exhibited good biosafety for whole blood and major organs during the degradation in vivo: during the degradation of AMPCs, excluding changes in some serum indicators, no tissue necrosis or inflammatory cell infiltration was observed in these organs, either by gross observation or histological analysis. These findings demonstrate that expecting to develop a highly functional and safe hemostatic agent based on Group 1 for rapid hemostasis applications in emergencies.
Collapse
Affiliation(s)
- Lihao Wu
- 12466Xiamen University, Xiamen, China
| | - Kang Ren
- 12466Xiamen University, Xiamen, China
| | - Gong Chen
- 12466Xiamen University, Xiamen, China
| | | | | | - Ling Xu
- 12466Xiamen University, Xiamen, China
| |
Collapse
|
7
|
De Berardinis L, Plazzotta S, Manzocco L. Optimising Soy and Pea Protein Gelation to Obtain Hydrogels Intended as Precursors of Food-Grade Dried Porous Materials. Gels 2023; 9:gels9010062. [PMID: 36661828 PMCID: PMC9858295 DOI: 10.3390/gels9010062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/04/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
Dried porous materials based on plant proteins are attracting large attention thanks to their potential use as sustainable food ingredients. Nevertheless, plant proteins present lower gelling properties than animal ones. Plant protein gelling could be improved by optimising gelation conditions by acting on protein concentration, pH, and ionic strength. This work aimed to systematically study the effect of these factors on the gelation behaviour of soy and pea protein isolates. Protein suspensions having different concentrations (10, 15, and 20% w/w), pH (3.0, 4.5, 7.0), and ionic strength (IS, 0.0, 0.6, 1.5 M) were heat-treated (95 °C for 15 min) and characterised for rheological properties and physical stability. Strong hydrogels having an elastic modulus (G') higher than 103 Pa and able to retain more than 90% water were only obtained from suspensions containing at least 15% soy protein, far from the isoelectric point and at an IS above 0.6 M. By contrast, pea protein gelation was achieved only at a high concentration (20%), and always resulted in weak gels, which showed increasing G' with the increase in pH and IS. Results were rationalised into a map identifying the gelation conditions to modulate the rheological properties of soy and pea protein hydrogels, for their subsequent conversion into xerogels, cryogels, and aerogels.
Collapse
|
8
|
Biswas S, Bhunia BK, Janani G, Mandal BB. Silk Fibroin Based Formulations as Potential Hemostatic Agents. ACS Biomater Sci Eng 2022; 8:2654-2663. [PMID: 35616246 DOI: 10.1021/acsbiomaterials.2c00170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Effective hemorrhage control is indispensable for life-threatening emergencies in defense fields and civilian trauma. During major injuries, hemostatic agents are applied externally to mimic and accelerate the natural hemostasis process. Commercially available topical hemostatic agents are associated with several limitations, e.g., burning sensation, necrosis, futile in severe injuries, and high costs of the products. In the present study, we developed silk fibroin fiber-based formulations and evaluated their use as a cost-effective potential hemostatic agent with shortened clotting time. Silk fiber-based powder was produced following the alkaline hydrolysis process, wherein Bombyx mori silk fibroin fibers were treated with sodium hydroxide (NaOH) solution that randomly chopped the silk microfibers. Physicochemical reaction parameters, e.g., reaction temperature, molarity of NaOH solution, and incubation time, were optimized to achieve the maximum yield of microfibers. The surface properties of alkaline hydrolyzed silk microfibers (AHSMf) were analyzed by field emission scanning electron microscopy and energy dispersive X-ray studies. The water uptake capacity of AHSMf and the change in pH and temperature (∼30 °C) during blood clotting were analyzed. Further, the hemostatic potential of AHSMf was evaluated by an in vitro whole blood clotting assay using both goat and human blood. The in vitro studies demonstrated a reduced blood clotting time (CT = 20-30 s), prothrombin time (PT = ∼27%), and activated partial thromboplastin time (APTT = ∼14%) in the presence of AHSMf when compared to silk hydrogel powder (devoid of NaOH). Thus, the developed AHSMf could be a promising material to serve as a potential hemostatic agent.
Collapse
Affiliation(s)
- Saptarshi Biswas
- Biomaterials and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, India
| | - Bibhas K Bhunia
- Biomaterials and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, India
| | - G Janani
- Biomaterials and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, India
| | - Biman B Mandal
- Biomaterials and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, India.,Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781 039, India.,School of Health Sciences and Technology, Indian Institute of Technology Guwahati, Guwahati 781 039, India
| |
Collapse
|
9
|
Kumar Dan A, Biswal B, Das M, Parida S, Kumar Parhi P, Das D. Aqueous and Chemical Extraction of Saponin of Acacia concinna (Willd.) Dc.: An effective Bio-surfactant Solution to Extract Silk Fibroin from Muga silk cocoons. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
10
|
Insights into the Role of Biopolymer-Based Xerogels in Biomedical Applications. Gels 2022; 8:gels8060334. [PMID: 35735678 PMCID: PMC9222565 DOI: 10.3390/gels8060334] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/21/2022] [Accepted: 05/25/2022] [Indexed: 12/18/2022] Open
Abstract
Xerogels are advanced, functional, porous materials consisting of ambient, dried, cross-linked polymeric networks. They possess characteristics such as high porosity, great surface area, and an affordable preparation route; they can be prepared from several organic and inorganic precursors for numerous applications. Owing to their desired properties, these materials were found to be suitable for several medical and biomedical applications; the high drug-loading capacity of xerogels and their ability to maintain sustained drug release make them highly desirable for drug delivery applications. As biopolymers and chemical-free materials, they have been also utilized in tissue engineering and regenerative medicine due to their high biocompatibility, non-immunogenicity, and non-cytotoxicity. Biopolymers have the ability to interact, cross-link, and/or trap several active agents, such as antibiotic or natural antimicrobial substances, which is useful in wound dressing and healing applications, and they can also be used to trap antibodies, enzymes, and cells for biosensing and monitoring applications. This review presents, for the first time, an introduction to biopolymeric xerogels, their fabrication approach, and their properties. We present the biological properties that make these materials suitable for many biomedical applications and discuss the most recent works regarding their applications, including drug delivery, wound healing and dressing, tissue scaffolding, and biosensing.
Collapse
|