Axial PEGylation of Tin Octabutoxy Naphthalocyanine Extends Blood Circulation for Photoacoustic Vascular Imaging.
Attachment of polyethylene glycol (PEG) can prolong blood circulation of biological molecules, a useful trait for a vascular imaging agent. Here, we present a route for modifying octabutoxy naphthalocyanine (ONc) with PEG, via axial conjugation following ONc chelation with Sn(IV) chloride (Sn-ONc). Tin chelation caused ONc absorbance to shift from 860 to 930 nm. Hydroxy terminated PEG was treated with sodium and then was axially attached to the tin, generating PEG-Sn-ONc. Unlike ONc or Sn-ONc, PEG-Sn-ONc was soluble in methanol. ONc and PEG-Sn-ONc were dissolved in polysorbate solutions and administered to mice intravenously. PEG-Sn-ONc demonstrated substantially longer blood circulation time than ONc, with a 4 times longer half-life and a nearly 10 times greater area under the curve. PEG-Sn-ONc gave rise to photoacoustic contrast and could be used for noninvasive brain vessel imaging even 24 h following injection. This work demonstrates that nonmetallic naphthalocyanines can be chelated with tin, and be axially modified with PEG for enhanced circulation times for long-term vascular imaging with photoacoustic tomography.
Haoyuan
H
Huang
Depeng
D
Wang
Yuzhen
Y
Zhang
College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University , Jinan 250014, P.R. China.
Yang
Y
Zhou
Jumin
J
Geng
Upendra
U
Chitgupi
Timothy R
TR
Cook
Jun
J
Xia
Jonathan F
JF
Lovell
D000818:Animals; D001921:Brain / Q000098:blood supply; D002560:Cerebrovascular Circulation; D051379:Mice; D009281:Naphthalenes / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D061088:Photoacoustic Techniques / Q000379:methods*; D011092:Polyethylene Glycols / Q000737:chemistry*; D014001:Tin / Q000737:chemistry*; D014054:Tomography / Q000379:methods*
D009281:Naphthalenes; D009942:Organometallic Compounds; C031721:naphthalene; D011092:Polyethylene Glycols; D014001:Tin