Abstract
Summary: Poly(vinyl alcohol) (PVA) and polyamidoamine (PAMAM) dendrimers are water‐soluble, biocompatible and biodegradable polymers, which have been widely applied in biomedical fields. In this paper, novel physically cross‐linked hydrogels composed of PVA and amine‐terminated PAMAM dendrimer G6‐NH~2~ were prepared by cyclic freezing/thawing treatment of aqueous solutions containing PVA and G6‐NH~2~. The FT‐IR analysis and elemental analysis indicated that PAMAM dendrimer G6‐NH~2~ was successfully introduced into the formed hydrogels, possibly via hydrogen bonds among hydroxyl groups, amide groups and amino groups in PVA and PAMAM dendrimer in the process of freezing‐thawing cycle. Compared with physically cross‐linked PVA hydrogel, PVA/G6‐NH~2~ hydrogels show higher swelling ratios and faster re‐swelling rate due to the higher hydrophilicity of PAMAM dendrimer G6‐NH~2~. Higher contents of G6‐NH~2~ in PVA/G6‐NH~2~ hydrogels resulted in higher swelling ratios and faster re‐swelling rates. With increasing freezing/thawing cyclic times, the swelling ratios and re‐swelling rates of PVA/G6‐NH~2~ hydrogels decreased, which is similar to that of physically cross‐linked PVA hydrogel. Combining the special host property of polyamidoamine dendrimer, these novel physically cross‐linked hydrogels are expected to have potential use in drug delivery, including improving drug‐loading amounts in hydrogels and prolonging drug release time.
Swelling ratios of physically cross‐linked PVA/G6‐NH~2~‐50 hydrogels prepared by three, six, nine freezing/thawing cycles. The swelling equilibrium experiments were carried out in distilled water at 25 °C.
imageSwelling ratios of physically cross‐linked PVA/G6‐NH~2~‐50 hydrogels prepared by three, six, nine freezing/thawing cycles. The swelling equilibrium experiments were carried out in distilled water at 25 °C.