Related Experiment Video
Updated: Jun 24, 2026
11:06
Encapsulating Cytochrome c in Silica Aerogel Nanoarchitectures without Metal Nanoparticles while Retaining Gas-phase Bioactivity
Published on: March 1, 2016
Balance between Coulombic interactions and physical confinement in silica hydrogel encapsulation
1Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA.
The Journal of Physical Chemistry. B
|April 7, 2009
Summary
Coulombic interactions significantly impact guest molecule mobility in silica hydrogels. Cationic rhodamine 6G (R6G) is immobilized, while anionic fluorescein (FL) remains mobile, highlighting differing microenvironments.
Area of Science:
- Materials Science
- Physical Chemistry
- Nanotechnology
Background:
- Silica hydrogels are versatile materials with applications in drug delivery and sensing.
- Understanding guest molecule behavior within hydrogels is crucial for optimizing their performance.
- Coulombic interactions and physical confinement are key factors influencing molecular mobility.
Purpose of the Study:
- To investigate the mobility of entrapped guest molecules within silica hydrogels.
- To evaluate the distinct effects of Coulombic interactions and physical confinement on molecular mobility.
- To compare the behavior of rhodamine 6G (R6G) and fluorescein (FL) within silica hydrogels.
Main Methods:
- Synthesis and characterization of silica hydrogels with entrapped guest molecules.
- Fluorescence recovery after photobleaching (FRAP) to measure diffusion coefficients.
- Varying pH and ionic strength to probe Coulombic interactions.
Main Results:
- Rhodamine 6G (R6G), a cationic dye, was largely immobilized within the silica hydrogel matrix.
- Fluorescein (FL), an anionic dye, exhibited significant mobility, with a diffusion coefficient of 2.1 x 10(-6) cm(2) s(-1).
- Coulombic interactions were found to be more dominant in hydrogels than in alcogels, influencing molecular placement and microenvironment.
Conclusions:
- The differing behaviors of R6G and FL are attributed to Coulombic interactions with the silica matrix.
- FL's mobility makes it suitable for monitoring hydrogel viscosity and confinement changes.
- R6G's strong attraction to silica makes it a reliable probe for silica colloid growth monitoring.
More Related Videos
Related Concept Videos
01:10Silica Gel Column Chromatography: Overview
Silica gel column chromatography is a technique for separating compounds using a column packed with silica gel as the stationary phase. This method relies on differences in the polarity of compounds. Based on their polarities, compounds move between the stationary phase (silica gel) and the mobile phase (the solvent), forming discrete bands in the column.
Polar components tend to bind strongly to the silica gel, causing them to move slowly through the column. In contrast, nonpolar compounds...
Polar components tend to bind strongly to the silica gel, causing them to move slowly through the column. In contrast, nonpolar compounds...
03:13Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...