Aggregation behavior of novel hyaluronan derivatives—a fluorescence probe study

Abstract

Aggregation properties of hydrophobized hyaluronan (hHA) in different molecular weights and degree of substitution were studied by pyrene and perylene fluorescence method. The critical aggregation concentration (cac) was determined by the pyrene I 1 /I 3 and perylene fluorescence intensity method. The value of the cac for the hHA in aqueous solution was measured at different molecular weights and at 293.2 K. The cac value varied both with the molecular weight and the degree of substitution and was between 0.610-0.003 gL −1. Pyrene Polarity Scale confirmed formation of hydrophobic domains of the relative hydrophobic index about 0.85.

Oral Gene Delivery with cyclo-(d-Trp-Tyr) Peptide Nanotubes

“…36,37,39 The ratio of the fluorescence intensity at 373 nm (I 1 ) and at 383 nm (I 3 ) was plotted against the logarithm of the concentration of associating molecules. 40 The CAC value was determined from the crossover point of the rapidly varying part and the nearly horizontal part at low concentrations. 41 6.…”

“…37,47 Briefly, 13 units of RQ1 RNase-free DNase I (Promega Biotech Co., Ltd., Madison, WI) and 100 μg of pCMV-lacZ with or without PNTs in a total volume of 200 μL was incubated at 37 °C. The mixture was sampled in each 10 μL of samples after incubating with DNase I at 37 °C for 0, 5,10,15,20,30,40,50,60,70,80, 100, and 120 min, and then 1 μL of RQ1 DNase I stop solution (Promega Biotech Co., Ltd., Madison, WI) was immediately added into each sample. The stability of pCMV-lacZ/PNT formulation with simulated gastric acid was performed according to a previous study.…”

“…The emission spectrum scan was performed from 350 to 460 nm using a fixed excitation wavelength of 339 nm with a constant pyrene concentration of 6 × 10 –7 M. The PNT concentrations were from 1.6 μg/mL to 1.6 mg/mL. CAC was determined by the pyrene I 1 / I 3 ratio method described in previous studies. ,, The ratio of the fluorescence intensity at 373 nm ( I 1 ) and at 383 nm ( I 3 ) was plotted against the logarithm of the concentration of associating molecules . The CAC value was determined from the crossover point of the rapidly varying part and the nearly horizontal part at low concentrations …”

Gel‐Like Structure of a Hexadecyl Derivative of Hyaluronic Acid for the Treatment of Osteoarthritis

“…Recently, a study on the aggregation behavior of a hydrophobized HA with C‐10 alkyl side chains at different degrees of substitution showed a closed aggregation process 9. These observations suggest that, in aqueous solutions, differences in macromolecular organizations have direct involvement in the mechanical characteristics of differently modified HA‐based polymers.…”

Preparation and catalytic behavior of antioxidant cassava starch with selenium active sites and hydrophobic microenvironments

“…Pyrene is a commonly used uorescent probe for testing the hydrophobicity of materials as its molecular uorescence emission spectrum is very sensitive to the polarity of the environment. 49,50 The hydrophobic pyrene molecules can be assembled in the hydrophobic microenvironments of the materials, resulting in a decrease in uorescence intensity ratio (I 1 /I 3 ) of the peak at l 1 ¼ 372 nm and the peak at l 3 ¼ 383 nm. 51 Therefore, the value of I 1 /I 3 can be used to characterize the hydrophobic microenvironments of the targeted materials, that is, the smaller the I 1 /I 3 , the stronger the hydrophobicity of the material.…”