AVS 49th International Symposium
    Biomaterials Wednesday Sessions
       Session BI+AS-WeM

Paper BI+AS-WeM5
Real-time AFM Investigations of the Enzymatic Degradation of DNA-polymer Dendrimer Complexes

Wednesday, November 6, 2002, 9:40 am, Room C-201

Session: Ambient Surface Science Techniques
Presenter: S.J.B. Tendler, University of Nottingham, UK
Authors: S.J.B. Tendler, University of Nottingham, UK
H.G. Abdelhady, University of Nottingham, UK
C.J. Roberts, University of Nottingham, UK
S. Allen, University of Nottingham, UK
M.C. Davies, University of Nottingham, UK
P.M. Williams, University of Nottingham, UK
Correspondent: Click to Email
Fundamental to surface recognition strategies is the need to develop both interfaces and imaging methods that allow the investigation of biomolecular recognition processes in solution, in-real time. One such set of processes is the enzymatic degradation of DNA, both when naked and when protected by polymeric (bio)materials. This system has clinical relevance in that polyelectrolyte complexes between polyamidoamine (PAMAM) dendrimers and DNA have emerged as potential non-viral vectors for therapeutic DNA delivery. Hence methods for analyzing the ability of PAMAM dendrimers to protect the DNA from degradative enzymes are of clinical significance. Here we have applied atomic force microscopy (AFM) in liquid to visualize at the molecular scale and in real time, the effect of the enzyme DNase I on generation 4 PAMAM dendrimers complexed with DNA (G4-DNA). The formation of G4-DNA is observed to provide a degree of protection to the DNA, the level of which rises with increasing PAMAM dendrimer to DNA ratio and to a certain degree with the time allowed for complexes to form.