Scientists from the Department of Chemical Engineering at McMaster University in Ontario, Canada wrote “Tuning drug release from smart microgel–hydrogel composites via cross-linking” for the February 2013 issue of the Journal of Colloid and Interface Science. In the article, the researchers used Spectra/Por dialysis tubing to purify polymerized microgels.


Abstract: Soft nanocomposite hydrogels consisting of thermoresponsive microgels physically entrapped or covalently cross-linked to a non-thermoresponsive hydrogel are synthesized and tested for their capacity to facilitate long-term drug release of a small molecule drug. Copolymer microgels based on N-isopropylacrylamide and acrylic acid were synthesized that exhibited ionic affinity for binding to bupivacaine, a cationic local anesthetic. These microgels were subsequently physically entrapped within an in situ-gelling carbohydrate-based hydrogel network cross-linked via hydrazide–aldehyde chemistry; alternately, hydrazide-functionalized microgels were prepared that covalently cross-linked to the bulk hydrogel phase. Both the overall rate of drug release and the magnitude of the burst release were significantly decreased when microgels were restricted from undergoing a phase transition between the preparation temperature of the nanocomposite (25 °C) and the test temperature (37 °C), whether deswelling was inhibited by increasing the cross-link density within the microgel itself or by cross-linking the microgel to the bulk hydrogel network. This result facilitates facile tuning of soft nanocomposite drug delivery systems to achieve targeted drug release kinetics. Click here to read the article.


Standard Grade Regenerated Cellulose (RC) is a clear, flexible and sturdy dialysis membrane with a “looser” molecular selectivity. This economical membrane is ideal for a broad range of applications in which there is a significant size difference between the MW species being separated.