Laterally sandwich-typed hydrogel columns with liner poly(N-isopropylacrylamide) layer: Preparation, swelling/deswelling kinetics and drug delivery characteristics

Abstract

A novel thermo-responsive hydrogel column, featured with both ends of linear poly(N-isopropylacrylamide) (PNIPAM) chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed hydrogel columns were fabricated by radical polymerization in a three-step process using a method of ice-melting synthesis. The initiating path, morphology and thermoresponsive characteristics of the prepared hydrogel columns were experimentally studied. The results show that the hydrogel column obtained by the initiator inside part has more quick swelling and deswelling rates responsing to temperature cycling than other hydrogels owing to linear PNIPAM chains to form supermacroporous structure. The proposed hydrogel structure provide a new mode of the phase transition behavior for thermo-sensitive “smart” or “intelligent” monodisperse micro-actuators, which is highly attractive for targeting drug delivery systems, chemical separations, and sensors and so on.

Keywords

ice-melting synthesis / laterally sandwich-typed hydrogel columns / swelling/de-swelling rates / poly(N-isopropylacrylamide)

References

[1] Pelton R. Temperature-sensitive Aqueous Microgels[J]. Adv. Colloid Interface Sci., 2000, 85(1): 1-33.

[2] Gao Y. X., Ji X. M., Yin Y. H., . Poly(N-isopropylacrylamide), Poly(methacrylic acid) and Their Copolymers for Oral Colon-specific Drug Delivery[J]. J. Wuhan Uni.Technol.-Mater. Sci. Ed., 2009, 24(4): 571-574.

[3] Kawaguchi H., Fujimoto K. Smart Latexes for Bioseparation[J]. Bioseparation, 1998, 7(4): 253-258.

[4] Hu Z. B., Chen Y. Y., Wang C. J., . Polymer Gels with Engineered Environmentally Responsive Surface Patterns[J]. Nature, 1998, 393(6681): 149-152.

[5] Bergbreiter D. E., Case B. L., Liu Y. S., . Poly(N-isopropylacrylamide) Soluble Polymer Supports in Catalysis and Synthesis[J]. Macromolecules, 1998, 31(18): 6 053-6 062.

[6] Shibayama M., Nagai K. Shr inking Kinetics of Poly(Nisopropylacrylamide) Gels T-jumped Across Their Volume Phase Transition Temperatures[J]. Macromolecules, 1999, 32(22): 7 461-7 468.

[7] Xiao X. C., Chu L. Y., Chen W. M., . Preparation of Submicron-sized Monodispersed Thermoresponsive Coreshell Hydrogel Microspheres[J]. Langmuir, 2004, 20(13): 5 247-5 253.

[8] Xiao X. C., Chu L. Y., Chen W. M., . Positively Thermo-sensitive Monodisperse Core-shell Microspheres[J]. Adv. Funct. Mater., 2003, 13(11): 847-852.

[9] Matsuoka H., Fujimoto K., Kawaguchi H. Stimuli-response of Microspheres Having Poly(N-isopropylacrymide) Shell[J]. Polymer J., 1999, 31(11–12): 1 139-1 144.

[10] Zhang X. Z., Chu C. C. Thermosensitinve PNIPAAm Cryogel with Superfast and Stable Oscillatory Properties[J]. Chem. Commun., 2003, 12: 1 446-1 447.

[11] Zhang X. Z., Zhuo R. X., Yang Y. Y. Using Mixed Solvent to Synthesize Temperature Sensitive Poly(N-isopropylacrylamide) Gel with Rapid Dynamics Properties[J]. Biomaterials, 2002, 23(5): 1 313-1 318.

[12] Zhuo R. X., Li W. Preparation and Characterization of Macroporous Poly(N-isopropylacrylamide) Hydrogels for the Controlled Release of Proteins[J]. J. Polym. Sci. Part A Polym. Chem., 2003, 41(1): 152-159.

[13] Kaneko Y., Sakai K., Kikuchi A., . Influence of Freely Mobile Grafted Chain Length on Dynamic Properties of Comb-type Grafted Poly(N-isopropylacrylamide) Hydrogels[J]. Macromolecules, 1995, 28(23): 7 717-7 723.