| 1. |
|
|
| 2. |
- Babakinejad, Babak, et al.
(författare)
-
Local delivery of molecules from a nanopipette for quantitative receptor mapping on live cells
- 2013
-
Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 85:19, s. 42-9333
-
Tidskriftsartikel (refereegranskat)abstract
- Using nanopipettes to locally deliver molecules to the surface of living cells could potentially open up studies of biological processes down to the level of single molecules. However, in order to achieve precise and quantitative local delivery it is essential to be able to determine the amount and distribution of the molecules being delivered. In this work, we investigate how the size of the nanopipette, the magnitude of the applied pressure or voltage, which drives the delivery, and the distance to the underlying surface influences the number and spatial distribution of the delivered molecules. Analytical expressions describing the delivery are derived and compared with the results from finite element simulations and experiments on delivery from a 100 nm nanopipette in bulk solution and to the surface of sensory neurons. We then developed a setup for rapid and quantitative delivery to multiple subcellular areas, delivering the molecule capsaicin to stimulate opening of Transient Receptor Potential Vanilloid subfamily member 1 (TRPV1) channels, membrane receptors involved in pain sensation. Overall, precise and quantitative delivery of molecules from nanopipettes has been demonstrated, opening up many applications in biology such as locally stimulating and mapping receptors on the surface of live cells.
|
|
| 3. |
- Ivanov, Aleksandar P, et al.
(författare)
-
On-Demand Delivery of Single DNA Molecules Using Nanopipets.
- 2015
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 9:4, s. 3587-3595
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the behavioral properties of single molecules or larger scale populations interacting with single molecules is currently a hotly pursued topic in nanotechnology. This arises from the potential such techniques have in relation to applications such as targeted drug delivery, early stage detection of disease, and drug screening. Although label and label-free single molecule detection strategies have existed for a number of years, currently lacking are efficient methods for the controllable delivery of single molecules in aqueous environments. In this article we show both experimentally and from simulations that nanopipets in conjunction with asymmetric voltage pulses can be used for label-free detection and delivery of single molecules through the tip of a nanopipet with "on-demand" timing resolution. This was demonstrated by controllable delivery of 5 kbp and 10 kbp DNA molecules from solutions with concentrations as low as 3 pM.
|
|
| 4. |
- Schobesberger, Sophie, et al.
(författare)
-
Nanoscale, Voltage-Driven Application of Bioactive Substances onto Cells with Organized Topography.
- 2016
-
Ingår i: Biophysical Journal. - : Elsevier BV. - 1542-0086 .- 0006-3495. ; 110:1, s. 141-146
-
Tidskriftsartikel (refereegranskat)abstract
- With scanning ion conductance microscopy (SICM), a noncontact scanning probe technique, it is possible both to obtain information about the surface topography of live cells and to apply molecules onto specific nanoscale structures. The technique is therefore widely used to apply chemical compounds and to study the properties of molecules on the surfaces of various cell types. The heart muscle cells, i.e., the cardiomyocytes, possess a highly elaborate, unique surface topography including transverse-tubule (T-tubule) openings leading into a cell internal system that exclusively harbors many proteins necessary for the cell's physiological function. Here, we applied isoproterenol into these surface openings by changing the applied voltage over the SICM nanopipette. To determine the grade of precision of our application we used finite-element simulations to investigate how the concentration profile varies over the cell surface. We first obtained topography scans of the cardiomyocytes using SICM and then determined the electrophoretic mobility of isoproterenol in a high ion solution to be -7 × 10(-9) m(2)/V s. The simulations showed that the delivery to the T-tubule opening is highly confined to the underlying Z-groove, and especially to the first T-tubule opening, where the concentration is ∼6.5 times higher compared to on a flat surface under the same delivery settings. Delivery to the crest, instead of the T-tubule opening, resulted in a much lower concentration, emphasizing the importance of topography in agonist delivery. In conclusion, SICM, unlike other techniques, can reliably deliver precise quantities of compounds to the T-tubules of cardiomyocytes.
|
|
