title: Cryopreservation of a small number of human sperm using enzymatically fabricated, hollow hyaluronan microcapsules handled by conventional ICSI procedures.
abstract: OBJECTIVE
  We investigated whether enzymatically fabricated hyaluronan (HA) microcapsules were feasible for use in the cryopreservation of a small number of sperm.
  
  
  METHODS
  HA microcapsules were fabricated using a system of water-immiscible fluid under laminar flow. Three sperm were injected into a hollow HA microcapsule using a micromanipulator. Capsules containing injected sperm were incubated in a freezing medium composed of sucrose as the cryoprotectant and then placed in a Cryotop® device and plunged into liquid nitrogen. After thawing, the capsule was degraded by hyaluronidase, and the recovery rate of sperm and their motility were investigated.
  
  
  RESULTS
  The HA microcapsule measuring 200 μm in diameter and with a 30-μm thick membrane was handled using a conventional intracytoplasmic sperm injection (ICSI) system, and the procedure involved the injection of sperm into the capsule. The HA microcapsules containing sperm were cryopreserved in a Cryotop® device and decomposed by the addition of hyaluronidase. The recovery rate of sperm after cryopreservation and degradation of HA microcapsules was sufficient for use in clinical practice (90 %).
  
  
  CONCLUSIONS
  Hollow HA microcapsules can be used for the cryopreservation of a small number of sperm without producing adverse effects on sperm quality.
authors.affiliation: IVF Namba Clinic, 1-17-28 Minamihorie, Nishi-ku, Osaka, 550-0015, Japan. tomita@ivfnamba.com.|Laboratory of Molecular Developmental Biology, Graduate School of Biology-Oriented Science and Technology, Kinki University, Wakayama, 649-6493, Japan. tomita@ivfnamba.com.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Tomita
authors.affiliation: Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Sakai
authors.affiliation: Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khanmohammadi
authors.affiliation: IVF Namba Clinic, 1-17-28 Minamihorie, Nishi-ku, Osaka, 550-0015, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamochi
authors.affiliation: IVF Namba Clinic, 1-17-28 Minamihorie, Nishi-ku, Osaka, 550-0015, Japan.
authors.forename: Shu
authors.initials: S
authors.lastname: Hashimoto
authors.affiliation: Laboratory of Molecular Developmental Biology, Graduate School of Biology-Oriented Science and Technology, Kinki University, Wakayama, 649-6493, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Anzai
authors.affiliation: HORAC Grand Front Osaka Clinic, 3-1 Ofuka-cho, Kita-ku, Osaka, 530-0011, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Morimoto
authors.affiliation: Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Taya
authors.affiliation: Laboratory of Molecular Developmental Biology, Graduate School of Biology-Oriented Science and Technology, Kinki University, Wakayama, 649-6493, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hosoi
mesh_terms: D002214:Capsules / Q000737:chemistry / Q000494:pharmacology; D015925:Cryopreservation; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry / Q000494:pharmacology; D008297:Male; D027724:Reproductive Techniques, Assisted; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*
chemical_list: D002214:Capsules; D006820:Hyaluronic Acid
keywords: Human sperm cryopreservation; Hyaluronan; ICSI; Microcapsule; Small number of sperm