Sticky “Delivering-From” Strategies Using Viral Vectors for Efficient Human Neural Stem Cell Infection by Bioinspired Catecholamines

Abstract

Controlled release of biosuprastructures, such as viruses, from surfaces has been a challenging task in providing efficient ex vivo gene delivery. Conventional controlled viral release approaches have demonstrated low viral immobilization and burst release, inhibiting delivery efficiency. Here, a highly powerful substrate-mediated viral delivery system was designed by combining two key components that have demonstrated great potential in the fields of gene therapy and surface chemistry, respectively: adeno-associated viral (AAV) vectors and adhesive catecholamine surfaces. The introduction of a nanoscale thin coating of catecholamines, poly(norepinephrine) (pNE) or poly(dopamine) (pDA) to provide AAV adhesion followed by human neural stem cell (hNSC) culture on sticky solid surfaces exhibited unprecedented results: approximately 90% loading vs 25% (AAV_bare surface), no burst release, sustained release at constant rates, approximately 70% infection vs 20% (AAV_bare surface), and rapid internalization. Importantly, the sticky catecholamine-mediated AAV delivery system successfully induced a physiological response from hNSCs, cellular proliferation by a single-shot of AAV encoding fibroblast growth factor-2 (FGF-2), which is typically achieved by multiple treatments with expensive FGF-2 proteins. By combining the adhesive material-independent surface functionalization characters of pNE and pDA, this new sticky "delivering-from" gene delivery platform will make a significant contribution to numerous fields, including tissue engineering, gene therapy, and stem cell therapy.

Inverted Quasi‐Spherical Droplets on Polydopamine–TiO2 Substrates for Enhancing Gene Delivery

“…These viral association effects confirmed that iQS droplets' steep curvature or active heat convection within the droplets triggered the close and rapid interaction of AAV vectors with hNSCs. Facilitating the physical contact between gene vectors and target cells within a short time span may be crucial for enhancing gene delivery efficiencies, as has consistently been observed in other studies …”

“…A specialized AAV vector that was engineered to specifically infect neural stem cell types, AAVr3.45, was used as a gene carrier in this study. Recombinant AAVr3.45 vectors carrying cDNA encoding interleukin‐10 (IL‐10), green fluorescent protein (GFP), and red fluorescent protein (DsRed), which were under the control of a cytomegalovirus (CMV) promoter, were successively packaged through the calcium phosphate transfection method . At 36 h posttransfection, the resulting AAV vectors were harvested and purified using a 1 mL HiTrap heparin column (GE Healthcare, Pittsburgh, PA) according to the manufacturer's instructions.…”

Polydopamine Inter‐Fiber Networks: New Strategy for Producing Rigid, Sticky, 3D Fluffy Electrospun Fibrous Polycaprolactone Sponges

“…Importantly, as depicted in Figure B, the adhesive moieties, catecholamines on the pDA chains, can be further employed as cues to promote robust immobilization of a variety of soluble factors or stable adherence of the sponges onto wet organ surfaces, thereby enlarging their application scopes as tissue engineering scaffolds and as drug delivering vehicles. The catechol groups can trigger the intimate interactions with abundant amines residing on organic molecules (i.e., soluble factors or cell surfaces), possibly transforming the fibrous sponges to become sticky . Thus, the sponges containing dopamine or pDA components (i.e., 3D‐PCL_mD or 3D‐PCL_pD sponges) exhibited the sticky characteristics on a wet porcine surface, while the other plain matrices (2D‐PCL and 3D‐PCL) were detached shortly by vigorous water‐rinsing (Figure D).…”

“…In addition, the quantity of pDA aggregates exposed on the 3D‐PCL_pD surfaces might not be sufficient to delay the discharges of immobilized molecules. Alternatively, additional pDA coating on the surface may provide a clue that can induce the sustained release of the surface‐bound molecules …”

Polydopamine-Assisted Surface Modification for Bone Biosubstitutes

“…As compared to traditional approaches with regard to surface modification or biomolecule immobilization, the PDA-assisted surface modification exhibits some exceptional characters containing facile processing, stable performance, and versatile application. Although the mechanism behind the formation of PDA coating layer on the material substitute still remains under debate, the PDA-assisted surface modification is expanding its applications to not only bone biosubstitutes but also cardiovascular devices, biosensors, neuron pseudosubstitutes, and sustainable drug delivery [18, 99–101]. …”