Enzymatically degradable thermogelling poly(alanine-co-leucine)-poloxamer- poly(alanine-co-leucine)

Hyo Jung Moon, Bo Gyu Choi, Min Hee Park, Min Kyung Joo, Byeongmoon Jeong

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


In the search for an enzymatically degradable thermogelling system, we are reporting poly(alanine-co-leucine)-poloxamer-poly(alanine-co-leucine) (PAL-PLX-PAL) aqueous solution. As the temperature increased, the polymer aqueous solution underwent sol-to-gel transition at 20-40 °C in a polymer concentration range of 3.0-10.0 wt %. The amphiphilic polymers of PAL-PLX-PAL form micelles in water, where the hydrophobic PALs form a core and the hydrophilic PLXs form a shell of the micelle. FTIR, circular dichroism, and 13C NMR spectra suggest that the -helical secondary structure of PAL is preserved; however, the molecular motion of the PLX significantly decreases in the sol-to-gel transition range of 20-50 °C. The polymer was degraded by proteolytic enzymes such as matrix metalloproteinase and elastase, whereas it was quite stable against cathepsin B, cathepsin C, and chymotrypsin or in phosphate-buffered saline (control). The in situ formed gel in the subcutaneous layer of rats showed a duration of 47 days, and H&E staining study suggests the histocompatibility of the gel in vivo with a marginal inflammation response of capsule formation. A model drug of bovine serum albumin was released over 1 month by the preset-gel injection method. The thermogelling PAL-PLX-PAL can be a promising biocompatible material for minimally invasive injectable drug delivery.

Original languageEnglish
Pages (from-to)1234-1242
Number of pages9
Issue number4
StatePublished - 11 Apr 2011


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