| 1. |
- Strömberg, Anette, et al.
(författare)
-
Manipulating the genetic identity and biochemical surface properties of individual cells with electric-field-induced fusion
- 2000
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Gothenburg Univ, Dept Chem, S-41296 Gothenburg, Sweden. Sahlgrens Univ Hosp, Inst Clin Neurosci, Dept Neurol, S-41345 Gothenburg, Sweden. : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 97:1, s. 7-11
-
Tidskriftsartikel (refereegranskat)abstract
- A method for cell-cell and cell-liposome fusion at the single-cell level is described. Individual cells or liposomes were first selected and manipulated either by optical trapping or by adhesion to a micromanipulator-controlled ultramicroelectrode. Spatially selective fusion of the cell-cell or cell-liposome pair was achieved by the application of a highly focused electric field through a pair of 5-mu m o.d. carbon-fiber ultramicroelectrodes. The ability to fuse together single cells opens new possibilities in the manipulation of the genetic and cellular makeup of individual cells in a controlled manner, In the study of cellular networks, for example, the alteration of the biochemical identity of a selected cell can have a profound effect on the behavior of the entire network. Fusion of a single liposome with a target cell allows the introduction of the liposomal content into the cell interior as well as the addition of lipids and membrane proteins onto the cell surface. This cell-liposome fusion represents an approach to the manipulation of the cytoplasmic contents and surface properties of single cells. As an example, we have introduced a membrane protein (gamma-glutamyltransferase) reconstituted in liposomes into the cell plasma membrane.
|
|
| 2. |
- Chiu, D T, et al.
(författare)
-
Electrical and optical methods for the manipulation and analyses of single cells
- 2001
-
Ingår i: CLINICAL DIAGNOSTIC SYSTEMS. - Univ Washington, Dept Chem, Seattle, WA 98195 USA. : SPIE-INT SOC OPTICAL ENGINEERING. - 0819439339 ; , s. 1-8
-
Konferensbidrag (refereegranskat)abstract
- This paper describes the use of focused electric fields and focused optical fields for the high resolution manipulation of single cells. A focused electric field, obtained with the use of ultramicroelectrodes (tip diameter similar to 5 mum), is used to electroporate and electrofuse individual cells selectively and with high spatial resolution. A focused optical field, in the form of an optical tweezer, is used to isolate single organelles from a cell as well as to position liposomes incorporated with receptors and transporters along the cell for the high-resolution sampling and probing of the cellular microenvironment.
|
|
| 3. |
- Karlsson, M, et al.
(författare)
-
Electroinjection of colloid particles and biopolymers into single unilamellar liposomes and cells for bioanalytical applications
- 2000
-
Ingår i: Analytical Chemistry. - Univ Gothenburg, Dept Chem, SE-41296 Gothenburg, Sweden. Univ Gothenburg, Dept Chem Phys, SE-41345 Gothenburg, Sweden. : AMER CHEMICAL SOC. - 0003-2700 .- 1520-6882. ; 72:23, s. 5857-5862
-
Tidskriftsartikel (refereegranskat)abstract
- A combined electroporation and pressure-driven microinjection method for efficient loading of biopolymers and colloidal particles into single-cell-sized unilamellar liposomes was developed. Single liposomes were positioned between a similar to2-mum tip diameter solute-filled glass micropipet, equipped with a Pt electrode, and a 5-mum-diameter carbon fiber electrode. A transient, 1-10 ms, rectangular waveform de voltage pulse (10-40 V/cm) was applied between the electrodes, thus focusing the electric field over the liposome. Dielectric membrane breakdown induced by the applied voltage pulse caused the micropipet tip to enter the liposome and a small volume (typically 50-500 x 10(-15) L) of fluorescein, YOYO-intercalated T7-phage DNA, 100-nm-diameter unilamellar liposomes, or fluorescent latex spheres could be injected into the intraliposomal compartment. We also demonstrate initiation of a chemical intercalation reaction between T2-phage DNA and YOYO-1 by dual injection into a single giant unilamellar liposome. The method was also successfully applied for loading of single cultured cells.
|
|
| 4. |
- Strömberg, Anette, et al.
(författare)
-
Microfluidic device for combinatorial fusion of liposomes and cells
- 2001
-
Ingår i: Analytical Chemistry. - Gothenburg Univ, Dept Chem, S-41296 Gothenburg, Sweden. : AMER CHEMICAL SOC. - 0003-2700 .- 1520-6882. ; 73:1, s. 126-130
-
Tidskriftsartikel (refereegranskat)abstract
- We describe an electrofusion-based technique for combinatorial synthesis of individual liposomes. A prototype device with containers for liposomes of different compositions and a fusion container was constructed. The sample containers had fluid contact with the fusion container through microchannels. Optical trapping was used to transport individual liposomes and cells through the microchannels into the fusion container. In the fusion container, selected pairs of liposomes were fused together using microelectrodes. A large number of combinatorially synthesized Liposomes with complex compositions and reaction systems can be obtained from small sets of precursor liposomes. The order of different reaction steps can be specified and defined by the fusion sequence. This device could also facilitate single cell-cell electrofusions (hybridoma production). This is exemplified by fusion of transported red blood cells.
|
|
