Gene Delivery by Immobilization to Cell-Adhesive Substrates

Abstract

Biomaterials can potentially enhance the delivery of viral and nonviral vectors for both basic science and clinical applications. Vectors typically consist of nucleic acids (DNA, RNA) packaged with proteins, lipids, or cationic polymers, which facilitate cellular internalization and trafficking. These vectors can associate with biomaterials that support cell adhesion, a process we term substrate-mediated delivery. Substrate immobilization localizes the DNA and the delivery vector to the cellular microenvironment. The interaction between the vector and substrate must be appropriately balanced to mediate immobilization, yet allow for cellular internalization. Balancing the binding between the biomaterial and the vector is dependent upon the surface chemistries of the material and the vector, which can be designed to provide both specific (e.g., biotin-avidin, the strongest known noncovalent interaction between a protein and its ligand) and nonspecific (e.g., van der Waals) interactions. In this review, we describe the biomaterial and vector properties that mediate binding and gene transfer, identify potential applications, and present opportunities for further development.

Surface polyethylene glycol enhances substrate-mediated gene delivery by nonspecifically immobilized complexes

“…Atomic force microscopy imaging of immobilized complexes supports this hypothesis, revealing that the presence of PEG on the surface significantly affects the morphology of the complexes, which correlates with greater high transfection levels and transfection efficiencies. The ability to control the morphology of the immobilized complexes and thus influence transfection levels could be translated to scaffolds for gene delivery in tissue engineering applications [5,6], as well other applications of substrate-mediated gene delivery, including transfected cell arrays [63]. Cell adhesion on EG-containing SAMs.…”

“…Monolayers were formed with combinations of four different alkanethiols (Table 1), including 1-decanethiol (DT10, CH 3 -terminated), 11-mercapto-1-undecanol (MUOH, OH-terminated), 11-mercaptoundecanoic acid (MUA, COO − -terminated) (Aldrich, St. Louis, MO) and HS (CH 2 ) 11 (OCH 2 CH 2 ) 6 OH, an EG-terminated alkanethiol (ProChimia, Gdansk, Poland). Alkanethiol solutions were freshly prepared in filtered, degassed ethanol.…”

“…As complexes bind to surfaces through mechanisms similar to proteins [6,15], their binding on surfaces containing PEG groups would also be expected to be reduced. However, binding studies reveal that increasing the percentage of EG groups on the surface did not affect the amount of DNA complex immobilization (Fig.…”

“…These systems include delivery through polymeric release, in which the DNA is released from a polymer scaffold, or substrate-mediated delivery, in which DNA is retained at the surface of a substrate. Substrate-mediated delivery, also termed solid phase delivery or reverse transfection, involves the immobilization of DNA, complexed with nonviral vectors, to a biomaterial or substrate that supports cell adhesion [6]. Cells cultured on the substrate are exposed to elevated DNA concentrations within the local microenvironment, which enhances transfection.…”

Localized viral vector delivery to enhance in situ regenerative gene therapy

“…9,29 Therefore, polymeric release and substratemediated delivery are two modified delivery systems that may overcome this mass transportation limitation. 30 Polymeric release methods incorporate viral vectors in the polymer matrix and controls release by polymer degradation. 16,24,[31][32][33] Viral vectors may release slowly to prolong therapeutic protein expression.…”