title: Microfluidic manufacture of rt-PA -loaded echogenic liposomes.
abstract: Echogenic liposomes (ELIP), loaded with recombinant tissue-type plasminogen activator (rt-PA) and microbubbles that act as cavitation nuclei, are under development for ultrasound-mediated thrombolysis. Conventional manufacturing techniques produce a polydisperse rt-PA-loaded ELIP population with only a small percentage of particles containing microbubbles. Further, a polydisperse population of rt-PA-loaded ELIP has a broadband frequency response with complex bubble dynamics when exposed to pulsed ultrasound. In this work, a microfluidic flow-focusing device was used to generate monodisperse rt-PA-loaded ELIP (μtELIP) loaded with a perfluorocarbon gas. The rt-PA associated with the μtELIP was encapsulated within the lipid shell as well as intercalated within the lipid shell. The μtELIP had a mean diameter of 5 μm, a resonance frequency of 2.2 MHz, and were found to be stable for at least 30 min in 0.5 % bovine serum albumin. Additionally, 35 % of μtELIP particles were estimated to contain microbubbles, an order of magnitude higher than that reported previously for batch-produced rt-PA-loaded ELIP. These findings emphasize the advantages offered by microfluidic techniques for improving the encapsulation efficiency of both rt-PA and perflurocarbon microbubbles within echogenic liposomes.
authors.affiliation: Department of Emergency Medicine, University of Cincinnati, 231 Albert Sabin Way, Suite 1551, Cincinnati, OH, 45267, USA. madhu.kandadai@gmail.com.|Department of Emergency Medicine, 231 Albert Sabin Way, CVC 3974, Cincinnati, OH, 45267-0769, USA. madhu.kandadai@gmail.com.
authors.forename: Madhuvanthi A
authors.initials: MA
authors.lastname: Kandadai
authors.affiliation: Department of Electrical Engineering and Computing Systems, University of Cincinnati, 812 Rhodes Hall, Cincinnati, OH, 45221, USA.
authors.forename: Prithviraj
authors.initials: P
authors.lastname: Mukherjee
authors.affiliation: Department of Internal Medicine, Division of Cardiovascular Health and Diseases, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267, USA.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Shekhar
authors.affiliation: Department of Emergency Medicine, University of Cincinnati, 231 Albert Sabin Way, Suite 1551, Cincinnati, OH, 45267, USA.
authors.forename: George J
authors.initials: GJ
authors.lastname: Shaw
authors.affiliation: Department of Electrical Engineering and Computing Systems, University of Cincinnati, 812 Rhodes Hall, Cincinnati, OH, 45221, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Papautsky
authors.affiliation: Department of Internal Medicine, Division of Cardiovascular Health and Diseases, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267, USA.
authors.forename: Christy K
authors.initials: CK
authors.lastname: Holland
mesh_terms: D004867:Equipment Design; D008081:Liposomes / Q000378:metabolism*; D045423:Microbubbles; D044085:Microfluidics; D010316:Particle Size; D010959:Tissue Plasminogen Activator / Q000378:metabolism*; D014465:Ultrasonics
chemical_list: D008081:Liposomes; D010959:Tissue Plasminogen Activator
keywords: Echogenic liposomes; Microfluidic flow-focusing; Recombinant tissue-type plasminogen activator; Stroke treatment; Ultrasound-mediated thrombolysis