title: Topological characterization of a bacterial cellulose-acrylic acid polymeric matrix.
abstract: This paper focuses on the micro- and nano-topological organization of a hydrogel, constituted by a mixture of bacterial cellulose and acrylic acid, and intended for biomedical applications. The presence of acrylic acid promotes the formation of two interpenetrated continuous phases: the primary "pores phase" (PP) containing only water and the secondary "polymeric network phase" (PNP) constituted by the polymeric network swollen by the water. Low field Nuclear Magnetic Resonance (LF NMR), rheology, Scanning Electron Microscopy (SEM) and release tests were used to determine the characteristics of the two phases. In particular, we found that this system is a strong hydrogel constituted by 81% (v/v) of PP phase the remaining part being occupied by the PNP phase. Pores diameters span in the range 10-100 μm, the majority of them (85%) falling in the range 30-90 μm. The high PP phase tortuosity indicates that big pores are not directly connected to each other, but their connection is realized by a series of interconnected small pores that rend the drug path tortuous. The PNP is characterized by a polymer volume fraction around 0.73 while mesh size is around 3 nm. The theoretical interpretation of the experimental data coming from the techniques panel adopted, yielded to the micro- and nano-organization of our hydrogel.
authors.affiliation: Faculty of Dentistry, Universiti Sains Islam Malaysia (USIM), Aras 15, Menara B, Persiaran MPAJ, Jalan Pandan Utama, Pandan Indah, 55100 Kuala Lumpur, Malaysia. Electronic address: nadia.halib@usim.edu.my.
authors.forename: N
authors.initials: N
authors.lastname: Halib
authors.affiliation: Centre for Drug Delivery Research, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia. Electronic address: mciamin@pharmacy.ukm.my.
authors.forename: M C I
authors.initials: MC
authors.lastname: Mohd Amin
authors.affiliation: School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia. Electronic address: gading@ukm.my.
authors.forename: I
authors.initials: I
authors.lastname: Ahmad
authors.affiliation: Department of Engineering and Architecture, University of Trieste, Via A. Valerio 6, 34127 Trieste, Italy. Electronic address: mikystars@hotmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Abrami
authors.affiliation: Department of Engineering and Architecture, University of Trieste, Via A. Valerio 6, 34127 Trieste, Italy. Electronic address: Simonamaria.fiorentino@phd.units.it.
authors.forename: S
authors.initials: S
authors.lastname: Fiorentino
authors.affiliation: Department of Engineering and Architecture, University of Trieste, Via A. Valerio 6, 34127 Trieste, Italy. Electronic address: rfarra@units.it.
authors.forename: R
authors.initials: R
authors.lastname: Farra
authors.affiliation: Department of Life Sciences, Cattinara University Hospital, Trieste University, Strada di Fiume 447, I-34149 Trieste, Italy. Electronic address: ggrassi@units.it.
authors.forename: G
authors.initials: G
authors.lastname: Grassi
authors.affiliation: Scuola Internazionale Superiore di Studi Avanzati (SISSA/ISAS), Via Bonomea 265, I-34136 Trieste, Italy. Electronic address: musiani@sissa.it.
authors.forename: F
authors.initials: F
authors.lastname: Musiani
authors.affiliation: School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia. Electronic address: romanol@dicamp.univ.trieste.it.
authors.forename: R
authors.initials: R
authors.lastname: Lapasin
authors.affiliation: School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia. Electronic address: mariog@dicamp.univ.trieste.it.
authors.forename: M
authors.initials: M
authors.lastname: Grassi
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D065546:Drug Liberation; D041822:Gluconacetobacter xylinus; D020100:Hydrogels / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D012212:Rheology; D013806:Theophylline / Q000737:chemistry
chemical_list: D000179:Acrylates; D020100:Hydrogels; D011108:Polymers; D002482:Cellulose; D013806:Theophylline; C036658:acrylic acid
keywords: Drug release; Low field NMR; Mesh-size; Porous gels; Rheology