Poly(vinyl alcohol) Scaffolds with Tailored Morphologies for Drug Delivery and Controlled Release

Abstract

Poly(vinyl alcohol) (PVA) scaffolds are prepared by a cryogenic process that consists of the unidirectional freezing of a PVA solution. The scaffolds exhibit a microchanneled structure, the morphology of which (in terms of pore diameter, surface area, and thickness of matter accumulated between adjacent microchannels) can be finely tailored by the averaged molecular weight of PVA, the PVA concentration in the solution, and the freezing rate of the PVA solution. The resulting PVA scaffolds are suitable substrates for drug‐delivery purposes, the drug release being controlled (from tens of minutes up to several days) by the morphology of the microchanneled structure. In vitro experiments reveal the efficiency of PVA scaffolds for controlling the release of ciprofloxacin into a bacteria culture medium.

Preparation of aligned porous gelatin scaffolds by unidirectional freeze-drying method

“…This was attributed to the effect of gelatin concentration on the growth of ice crystals during the freeze stage. The effect of the concentration on the morphology of the gelatin scaffolds is similar to the results for the water/PVA system obtained by del Monte's group [28]. In a gelatin solution, water molecules were separated by the gelatin macromolecules, and this blocked the water molecules from concentrating and arranging during freezing.…”

“…The unidirectional freeze-drying method has been exploited for preparing various aligned porous materials, including organic [16][17][18][19][20], inorganic [21][22][23][24][25] and composite [26,27] [21,27], suggesting that these HAP-based materials could be useful for load-bearing applications such as artificial bone. Del Monte et al fabricated poly(vinyl alcohol) (PVA) scaffolds with tailored morphologies for drug delivery and controlled release [28]. The size of the tubular pores, the surface area and the pore wall thickness can be adjusted by varying the molecular weight and solution concentration of PVA, as well as the freezing speed.…”

Controlled freezing and freeze drying: a versatile route for porous and micro-/nano-structured materials

“…The spacing between the aligned walls can be tuned from 12 to 50 µm over a range of freezing rates of 10-100 µm s −1 . 6 Del Monte et al 37 investigated the preparation of aligned porous PVA and their use for drug delivery. Higher concentrations of PVA (7.8 and 10 wt%) with the same molecular weight led to smaller pore sizes.…”

Fabrication of Graphene–Polymer Nanocomposites With Higher‐Order Three‐Dimensional Architectures

“…The former were fabricated by ice-segregation-induced self-assembly (ISISA) of frozen aqueous dispersions containing homogeneous mixtures of polystyrene sulfonate-stabilized graphene sheets (PSS-G) and poly(vinyl alcohol) (PVA) (Scheme 1i). We show that this method, which has been previously employed to produce porous architectures with potential uses in drug release, catalysis, electronics, and biotechnology, [18,19] is highly applicable to the directional freeze casting of PSS-G or GO aqueous dispersions to produce self-supporting high-surface-area monoliths with internally aligned macro-and mesoscale porosity. In addition, PSS-G-coated polymer microparticles or hollow micrometer-sized PSS-G spheres were prepared by the controlled aqueous deposition of negatively charged PSS-G dispersions on the surface of positively charged polymer beads (Scheme 1ii).…”