title: [Preparation and characterization of microbubbles loaded with hydrogen sulfide].
abstract: OBJECTIVE
  To prepare a phospholipid-coated microbubble loaded with hydrogen sulfide (HSMB) and evaluate its physicochemical and acoustic properties.
  
  
  METHODS
  Hydrogen sulfide and perfluoropropane were mixed at the ratios of 4:0, 3:1, 2:2, 1:3, and 0:4 to prepare hydrogen sulfide-loaded microbubbles (termed HSMB4:0, HSMB3:1, HSMB2:2, HSMB1:3, and HSMB0:4, respectively). The microbubble concentration and diameter were investigated and their stability were evaluated. The optimal ratio of hydrogen sulfide and perfluoropropane was determined according to the changes of microbubble concentration. The changes of dissolved hydrogen sulfide and concentration of the microbubbles were investigated after exposure to ultrasound, and their acoustic enhancement effects in the myocardium and kidney were observed after intravenous injection in rats.
  
  
  RESULTS
  HSMBs were milky in color and spherical in shape without aggregations. The concentrations of HSMB4:0 and HSMB3:1 were lower than that of HSMB2:2 and decreased with time. HSMB2:2, HSMB1:3 and HSMB0:4 showed comparable concentrations and were stable within 72 h. After exposure to ultrasound, the concentration of HSMB2:2 decreased while the dissolved hydrogen sulfide increased significantly. Intravenous injection of HSMB2:2 produced a satisfactory contrast-enhancing effect in the myocardium and kidney of rats.
  
  
  CONCLUSIONS
  HSMB prepared with the hydrogen sulfide to perfluoropropane ratio of 2:2 has excellent contrast-enhancing effect and is capable of carrying and releasing hydrogen sulfide upon ultrasound exposure to potentially allow visual site-specific delivery of hydrogen sulfide.
authors.affiliation: Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. E-mail: gangbinchen@126.com.
authors.forename: Gangbin
authors.initials: G
authors.lastname: Chen
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Xinzhong
authors.initials: X
authors.lastname: Li
authors.forename: Lintao
authors.initials: L
authors.lastname: Zhong
authors.forename: Juefei
authors.initials: J
authors.lastname: Wu
authors.forename: Jianping
authors.initials: J
authors.lastname: Bin
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry; D006321:Heart; D006862:Hydrogen Sulfide / Q000737:chemistry*; D007668:Kidney; D045423:Microbubbles; D010743:Phospholipids / Q000737:chemistry; D051381:Rats; D014465:Ultrasonics
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; D010743:Phospholipids; C042852:perflutren; D006862:Hydrogen Sulfide