title: pH shift assembly of adenoviral serotype 5 capsid protein nanosystems for enhanced delivery of nanoparticles, proteins and nucleic acids.
abstract: Empty adenovirus serotype 5 (Ad5) capsids devoid of viral genome were developed as a novel delivery system for nanoparticles, proteins, and nucleic acids. Ad5 capsids of 110 nm diameter undergo an increase in particle size to 1637 nm in 1mM acetic acid at pH4.0 and then shrink to 60 nm, following pH reversal to 7.4. These pH shifts induced reversible changes in capsid zeta potential and secondary structure and irreversible changes in tertiary structure of capsid proteins. Using pH shift dependent changes in capsid size and structure, 20 nm fluorescent nanoparticles, FITC-BSA, and Alexa Fluor® 488 conjugated siRNA were encapsulated with high efficiency in Ad5 capsids, as confirmed by electron microscopy and/or flow cytometry. HEK cell uptake with capsid delivery system was 7.8-, 7.4-, and 2.9-fold greater for nanoparticles, FITC-BSA, and Alexa-siRNA, respectively, when compared to plain solutes. Physical mixtures of capsids and fluorescent solutes exhibited less capsid associated fluorescence intensity and cell uptake. Further, unlike physical mixture, pH shift assembled Ad5 capsids protected siRNA from RNase degradation. Ad5 capsids before and after pH shift exhibited endolysosomal escape. Thus, empty Ad5 capsids can encapsulate a variety of solutes based on pH shift assembly, resulting in enhanced cellular delivery.
authors.affiliation: Nanomedicine and Drug Delivery Laboratory, Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, USA.
authors.forename: Vidhya R
authors.initials: VR
authors.lastname: Rao
authors.affiliation: Nanomedicine and Drug Delivery Laboratory, Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, USA.
authors.forename: Arun K
authors.initials: AK
authors.lastname: Upadhyay
authors.affiliation: Nanomedicine and Drug Delivery Laboratory, Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, USA; Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, USA; Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, USA. Electronic address: uday.kompella@ucdenver.edu.
authors.forename: Uday B
authors.initials: UB
authors.lastname: Kompella
mesh_terms: D000256:Adenoviridae / Q000737:chemistry*; D002213:Capsid / Q000737:chemistry; D036022:Capsid Proteins / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry; D016650:Fluorescein-5-isothiocyanate / Q000008:administration & dosage / Q000031:analogs & derivatives*; D005456:Fluorescent Dyes / Q000008:administration & dosage*; D018014:Gene Transfer Techniques; D057809:HEK293 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D053758:Nanoparticles / Q000008:administration & dosage*; D010316:Particle Size; D017433:Protein Structure, Secondary; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D012710:Serum Albumin, Bovine / Q000008:administration & dosage*
chemical_list: D036022:Capsid Proteins; D004337:Drug Carriers; D005456:Fluorescent Dyes; D034741:RNA, Small Interfering; C039217:fluorescein isothiocyanate bovine serum albumin; D012710:Serum Albumin, Bovine; D016650:Fluorescein-5-isothiocyanate
keywords: Adenovirus type 5; Capsid delivery system; Gene delivery; Nanoparticle delivery; Protein delivery