Fabrication of cross-linked alginate beads using electrospraying for adenovirus delivery.

Cross-linked alginate beads containing adenovirus (Ad) were successfully fabricated using an electrospraying method to achieve the protection and release of Ad in a controlled manner. An aqueous alginate solution containing Ad was electrosprayed into an aqueous phase containing a cross-linking agent (calcium chloride) at different process variables (voltages, alginate concentrations, and flow rates). Alginate beads containing Ad were used for transduction of U343 glioma cells and the transduction efficiency of the alginate beads was measured by quantification of gene expression using a fluorescence-activated cell sorter at different time points. In vitro results of gene expression revealed that the Ad encapsulated in the alginate beads with 0.5 wt% of alginate concentration exhibited a high activity for a long period (over 7 days) and was released in a sustained manner from the alginate beads. The Ad-encapsulating alginate beads could be promising materials for local delivery of Ad at a high concentration into target sites.

Ionically crosslinked Ad/chitosan nanocomplexes processed by electrospinning for targeted cancer gene therapy.

For effective cancer gene therapy, systemic administration of tumor-targeting adenoviral (Ad) complexes is critical for delivery to both primary and metastatic lesions. Electrospinning was used to generate nanocomplexes of Ad, chitosan, poly(ethylene glycol) (PEG), and folic acid (FA) for effective FA receptor-expressing tumor-specific transduction. The chemical structure of the Ad/chitosan-PEG-FA nanocomplexes was characterized by NMR and FT-IR, and the diameter and surface charge were analyzed by dynamic light scattering and zeta potentiometry, respectively. The average size of Ad/chitosan-PEG-FA nanocomplexes was approximately 140 nm, and the surface charge was 2.1 mV compared to -4.9 mV for naked Ad. Electron microscopy showed well-dispersed, individual Ad nanocomplexes without aggregation or degradation. Ad/chitosan nanocomplexes retained biological activity without impairment of the transduction efficiency of naked Ad. The transduction efficiency of Ad/chitosan-PEG-FA was increased as a function of FA ratio in FA receptor-expressing KB cells, but not in FA receptor-negative U343 cells, demonstrating FA receptor-targeted viral transduction. In addition, the transduction efficiency of Ad/chitosan-PEG-FA was 57.2% higher than chitosan-encapsulated Ad (Ad/chitosan), showing the superiority of FA receptor-mediated endocytosis for viral transduction. The production of inflammatory cytokine, IL-6 from macrophages was significantly reduced by Ad/chitosan-PEG-FA nanocomplexes, implying the potential for use in systemic administration. These results clearly demonstrate that cancer cell-targeted viral transduction by Ad/chitosan-PEG-FA nanocomplexes can be used effectively for metastatic tumor treatment with reduced immune reaction against Ad.