title: Collagen tissue treated with chitosan solutions in carbonic acid for improved biological prosthetic heart valves.
abstract: Calcification of bovine pericardium dramatically shortens typical lifetimes of biological prosthetic heart valves and thus precludes their choice for younger patients. The aim of the present work is to demonstrate that the calcification is to be mitigated by means of treatment of bovine pericardium in solutions of chitosan in carbonic acid, i.e. water saturated with carbon dioxide at high pressure. This acidic aqueous fluid unusually combines antimicrobial properties with absolute biocompatibility as far as at normal pressure it decomposes spontaneously and completely into H2O and CO2. Yet, at high pressures it can protonate and dissolve chitosan materials with different degrees of acetylation (in the range of 16-33%, at least) without any further pretreatment. Even exposure of the bovine pericardium in pure carbonic acid solution without chitosan already favours certain reduction in calcification, somewhat improved mechanical properties, complete biocompatibility and evident antimicrobial activity of the treated collagen tissue. The reason may be due to high extraction ability of this peculiar compressed fluidic mixture. Moreover, exposure of the bovine pericardium in solutions of chitosan in carbonic acid introduces even better mechanical properties and highly pronounced antimicrobial activity of the modified collagen tissue against adherence and biofilm formation of relevant Gram-positive and Gram-negative strains. Yet, the most important achievement is the detected dramatic reduction in calcification for such modified collagen tissues in spite of the fact that the amount of the thus introduced chitosan is rather small (typically ca. 1wt.%), which has been reliably detected using original tritium labelling method. We believe that these improved properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurised solutions in carbonic acid.
authors.affiliation: Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1-2, Moscow 119991, Russian Federation; Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991, Russian Federation. Electronic address: glm@spm.phys.msu.ru.
authors.forename: Marat O
authors.initials: MO
authors.lastname: Gallyamov
authors.affiliation: Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991, Russian Federation.
authors.forename: Ivan S
authors.initials: IS
authors.lastname: Chaschin
authors.affiliation: Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1-2, Moscow 119991, Russian Federation.
authors.forename: Marina A
authors.initials: MA
authors.lastname: Khokhlova
authors.affiliation: Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991, Russian Federation.
authors.forename: Timofey E
authors.initials: TE
authors.lastname: Grigorev
authors.affiliation: Bakulev Scientific Center for Cardiovascular Surgery of the Russian Academy of Medical Sciences, Roublyevskoe Sh. 135, Moscow 121552, Russian Federation.
authors.forename: Natalia P
authors.initials: NP
authors.lastname: Bakuleva
authors.affiliation: Bakulev Scientific Center for Cardiovascular Surgery of the Russian Academy of Medical Sciences, Roublyevskoe Sh. 135, Moscow 121552, Russian Federation.
authors.forename: Irina G
authors.initials: IG
authors.lastname: Lyutova
authors.affiliation: Bakulev Scientific Center for Cardiovascular Surgery of the Russian Academy of Medical Sciences, Roublyevskoe Sh. 135, Moscow 121552, Russian Federation.
authors.forename: Janna E
authors.initials: JE
authors.lastname: Kondratenko
authors.affiliation: Radiochemistry Division, Faculty of Chemistry, Lomonosov Moscow State University, Leninskie gory 1-2, Moscow 119991, Russian Federation.
authors.forename: Gennadii A
authors.initials: GA
authors.lastname: Badun
authors.affiliation: Radiochemistry Division, Faculty of Chemistry, Lomonosov Moscow State University, Leninskie gory 1-2, Moscow 119991, Russian Federation.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Chernysheva
authors.affiliation: Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1-2, Moscow 119991, Russian Federation; Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991, Russian Federation.
authors.forename: Alexei R
authors.initials: AR
authors.lastname: Khokhlov
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology; D001705:Bioprosthesis; D002255:Carbonic Acid / Q000737:chemistry*; D002417:Cattle; D048271:Chitosan / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry* / Q000378:metabolism; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006350:Heart Valve Prosthesis; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry; D051379:Mice; D041681:NIH 3T3 Cells; D010496:Pericardium / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D012834:Silver / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013718:Tensile Strength; D014184:Transplantation, Homologous; D014316:Tritium / Q000737:chemistry
chemical_list: D000890:Anti-Infective Agents; D012996:Solutions; D014316:Tritium; D012834:Silver; D002255:Carbonic Acid; D003094:Collagen; D048271:Chitosan
keywords: Antimicrobial activity; Biological prosthetic heart valve; Bovine pericardium; Calcification; Carbonic acid; Chitosan