Instructing Cells with Programmable Peptide-DNA Hybrids

Instructing Cells with Programmable Peptide-DNA Hybrids

Ronit Freeman¹*, Nicholas Stephanopoulos¹*, Samuel I. Stupp¹

1. Simpson Querrey Institute for BioNanotechnology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, US, Email: s-stupp@northwestern.edu

 

The native extracellular matrix is a space in which signals can be displayed dynamically and reversibly, positioned with nanoscale precision, and combined synergistically to control cell function. Artificial forms of this matrix for tissue regeneration need to recapitulate these three characteristics in a single molecular platform. Most efforts in this area have effectively addressed only one of these three key phenomena, and focused mainly on static cell adhesion or irreversible switching of bioactivity. Here we describe a molecular system that can be programmed to control the dynamics, spatial positioning, and combinatorial synergies of signals in extracellular matrices. In this approach, a biological signal is immobilized to a surface through DNA tethers, Figure 1. By engineering a series of tethers responsive to different stimuli, we show that cells adhered and spread on the surface reversibly. The DNA was also used as a molecular ruler to control the distance-dependent synergy between two adhesion peptides. Finally, orthogonal DNA tethers enabled the binding of both a peptide and a bioactive protein to the surface in order to promote cell differentiation. This peptide/protein-DNA (P-DNA) platform controls the way different signals are presented to cells and their relative spacing and confers superior reversibility by employing a set of bio-friendly stimuli. Multiple orthogonal DNA handles can be designed to allow for the selective presentation of different signals, with the ability to independently up- or down-regulate each over time. In principle, the anchoring strand can be attached to any type of material, including three-dimensional hydrogels, to better emulate the properties of the ECM.

Figure 1. Schematics of a DNA-modified surface used for the stimulus-responsive presentation of bio-active peptides and proteins in order to control cell adhesion, synergistic effects and differentiation.