Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes
The development of a strategy to investigate interfacial phenomena at lipid membranes is practically useful because most essential biomolecular interactions occur at cell membranes. In this study, a colorimetric method based on cysteine-encapsulated liposomes was examined using gold nanoparticles as...
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| Format: | Article |
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MDPI AG
2022-09-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/23/18/10566 |
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| author | Trang Thi Thuy Nguyen Seungjoo Haam Joon-Seo Park Sang-Wha Lee |
| author_facet | Trang Thi Thuy Nguyen Seungjoo Haam Joon-Seo Park Sang-Wha Lee |
| author_sort | Trang Thi Thuy Nguyen |
| collection | DOAJ |
| description | The development of a strategy to investigate interfacial phenomena at lipid membranes is practically useful because most essential biomolecular interactions occur at cell membranes. In this study, a colorimetric method based on cysteine-encapsulated liposomes was examined using gold nanoparticles as a probe to provide a platform to report an enzymatic activity at lipid membranes. The cysteine-encapsulated liposomes were prepared with varying ratios of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol through the hydration of lipid films and extrusions in the presence of cysteine. The size, composition, and stability of resulting liposomes were analyzed by scanning electron microscopy (SEM), dynamic light scattering (DLS), nuclear magnetic resonance (NMR) spectroscopy, and UV-vis spectrophotometry. The results showed that the increased cholesterol content improved the stability of liposomes, and the liposomes were formulated with 60 mol % cholesterol for the subsequent experiments. Triton X-100 was tested to disrupt the lipid membranes to release the encapsulated cysteine from the liposomes. Cysteine can induce the aggregation of gold nanoparticles accompanying a color change, and the colorimetric response of gold nanoparticles to the released cysteine was investigated in various media. Except in buffer solutions at around pH 5, the cysteine-encapsulated liposomes showed the color change of gold nanoparticles only after being incubated with Triton X-100. Finally, the cysteine-encapsulated liposomal platform was tested to report the enzymatic activity of phospholipase A<sub>2</sub> that hydrolyzes phospholipids in the membrane. The hydrolysis of phospholipids triggered the release of cysteine from the liposomes, and the released cysteine was successfully detected by monitoring the distinct red-to-blue color change of gold nanoparticles. The presence of phospholipase A<sub>2</sub> was also confirmed by the appearance of a peak around 690 nm in the UV-vis spectra, which is caused by the cysteine-induced aggregation of gold nanoparticles. The results demonstrated that the cysteine-encapsulated liposome has the potential to be used to investigate biological interactions occurring at lipid membranes. |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-09T23:45:39Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-4db900aac97845f183628cb4e517aa922023-11-23T16:43:56ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672022-09-0123181056610.3390/ijms231810566Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid MembranesTrang Thi Thuy Nguyen0Seungjoo Haam1Joon-Seo Park2Sang-Wha Lee3Department of Chemical and Biological Engineering, Gachon University, Seongnam-si 13120, KoreaDepartment of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03722, KoreaDepartment of Chemistry, Eastern University, St. Davids, PA 19087, USADepartment of Chemical and Biological Engineering, Gachon University, Seongnam-si 13120, KoreaThe development of a strategy to investigate interfacial phenomena at lipid membranes is practically useful because most essential biomolecular interactions occur at cell membranes. In this study, a colorimetric method based on cysteine-encapsulated liposomes was examined using gold nanoparticles as a probe to provide a platform to report an enzymatic activity at lipid membranes. The cysteine-encapsulated liposomes were prepared with varying ratios of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol through the hydration of lipid films and extrusions in the presence of cysteine. The size, composition, and stability of resulting liposomes were analyzed by scanning electron microscopy (SEM), dynamic light scattering (DLS), nuclear magnetic resonance (NMR) spectroscopy, and UV-vis spectrophotometry. The results showed that the increased cholesterol content improved the stability of liposomes, and the liposomes were formulated with 60 mol % cholesterol for the subsequent experiments. Triton X-100 was tested to disrupt the lipid membranes to release the encapsulated cysteine from the liposomes. Cysteine can induce the aggregation of gold nanoparticles accompanying a color change, and the colorimetric response of gold nanoparticles to the released cysteine was investigated in various media. Except in buffer solutions at around pH 5, the cysteine-encapsulated liposomes showed the color change of gold nanoparticles only after being incubated with Triton X-100. Finally, the cysteine-encapsulated liposomal platform was tested to report the enzymatic activity of phospholipase A<sub>2</sub> that hydrolyzes phospholipids in the membrane. The hydrolysis of phospholipids triggered the release of cysteine from the liposomes, and the released cysteine was successfully detected by monitoring the distinct red-to-blue color change of gold nanoparticles. The presence of phospholipase A<sub>2</sub> was also confirmed by the appearance of a peak around 690 nm in the UV-vis spectra, which is caused by the cysteine-induced aggregation of gold nanoparticles. The results demonstrated that the cysteine-encapsulated liposome has the potential to be used to investigate biological interactions occurring at lipid membranes.https://www.mdpi.com/1422-0067/23/18/10566liposomecysteinegold nanoparticlescolorimetric detectionphospholipase A<sub>2</sub>Triton X-100 |
| spellingShingle | Trang Thi Thuy Nguyen Seungjoo Haam Joon-Seo Park Sang-Wha Lee Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes International Journal of Molecular Sciences liposome cysteine gold nanoparticles colorimetric detection phospholipase A<sub>2</sub> Triton X-100 |
| title | Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes |
| title_full | Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes |
| title_fullStr | Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes |
| title_full_unstemmed | Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes |
| title_short | Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes |
| title_sort | cysteine encapsulated liposome for investigating biomolecular interactions at lipid membranes |
| topic | liposome cysteine gold nanoparticles colorimetric detection phospholipase A<sub>2</sub> Triton X-100 |
| url | https://www.mdpi.com/1422-0067/23/18/10566 |
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