Illustration of cells patterned over a DPN-fabricated protein and polymer array for targeted delivery. Image source: Lab Chip, 2012. 12: p. 2643–2648.

DPN for Targeted Delivery to Single Cells

Introduction

Dip Pen Nanolithography® (DPN®) is capable of precisely patterning multiple materials onto a surface and subsequently fabricating custom cellular arrays over these features. In this way, single cells can be exposed to different microenvironmental conditions, enabling multiplexed variable analyses critical to cell function studies. The DPN technique, which was recently featured on the cover of the journal Lab on a Chip, can perform assays with high statistical significance and low numbers of cells.

DPN for Targeted Delivery to Single Cells

The significance of single cell analysis is becoming increasingly evident for applications in cancer, stem cell development, and cytotoxicity. Although downstream analysis at the single cell level is common, until recently techniques for modulation of upstream events have been limited. Generally, heterogeneous cells have been exposed to an external stimulus, and the readout performed with cell isolation or imaging techniques. With the ability to deposit features at the sub-cellular (< 10 µm) scale, DPN is now emerging as a powerful technique to fabricate cell microenvironments for the isolation, culture and analysis of live single cells exposed to different materials.

Image of cells patterned over a DPN-fabricated protein and polymer array. After attachment the cells are labeled (colored) differently, demonstrating the ability to deliver multiple materials to cells within hundreds of microns of each other. Scale bar = 100 µm. Image source: Lab Chip, 2012. 12: p. 2643–2648.

NanoInk's NLP 2000 System has been used to pattern cell adhesive fibronectin in a series of sub-cellular dots. These areas are then readdressed with micro domains of polymers loaded with different fluorescently-tagged materials. The fibronectin squares serve to capture single cells, while the polymer micro domains deliver a defined dose of a material (such as a live cell indicator, a nanoparticle or, potentially, a drug) to each cell. After incubation, arrays can be imaged to determine extent of cell binding and response of individual cells to delivered materials

The ability to precisely control the cellular microenvironment using DPN-generated arrays is expected to advance the in vitro analysis of individual cell function within a heterogeneous population of cells. NanoInk's miniaturized cell based assays have the ability to generate multiplexed data from a very small number of cells with high statistical significance, a benefit particularly important in studies involving the analysis of primary cells, small tissue biopsies, or rare and hard to characterize cells (like stem cells or circulating tumor cells).

Want to learn even more about targeted delivery applications using Dip Pen Nanolithography? Contact us! For information on other DPN applications see the Applications tab.

Relevant references

1. Collins, J.M., Lam, R.T.S., Yang, Z., Semsarieh, B., Smetana, A.B., and Nettikadan, S., Lab Chip, 2012. 12: p. 2643–2648.
   
2. Chen, C.S., Mrksich, M., Huang, S., Whitesides, G.M., and Ingber, D.E., Science, 1997. 276: p. 1425.
   
3. Collins, J.M. and Nettikadan, S., Anal. Biochem., 2011. 419: p. 339.
   
4. Scadden, D.T., Nature, 2006. 441: p. 1075.
   

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