| Nanogels are a type of water dispersible, crosslinked polymeric nanoparticles. Because of their small size, porous structure, swelling behavior in different environments and ability to be functionalized, they are potential carriers for drugs and other molecules in biological systems.; In this work, polyacrylamide (PAM) nanogels (10--100 nm) with narrow size distribution were synthesized by inverse microemulsion polymerization. Systematic modifications by a two-step postgrafting strategy were carried out to prepare functional nanogels containing hydrophobic and/or ionic groups.; Drug encapsulation experiments using amitriptyline as target drug molecule were conducted with these nanogels in order to determine the use of nanogels for removal of overdosed drugs. The nanogels, chemically modified for hydrophobicity and electrostatic charge, show enhanced ability for drug binding when compared to the unmodified nanogels. The media generally interact with pendant groups in the gel network therefore cause the binding ability variation. The crosslinking density does not affect the drug interaction directly but affect the capacity of nanogels.; The drug binding data with various nanogels under different conditions were analyzed based on a phase partitioning model. The drug activity coefficient, partition coefficient and the free energy of the drug binding process were calculated using a Matlab program. It is shown that the drug molecules are bound to the polymer and the polymer network of gels provides sites for the drug and other ion species.; Through the calculated free energy, it indicates that the interactions between nanogels and drug species are energy-favored processes. These results prove nanogels are desired material for drug binding and drug delivery types of applications and the flexibility in structural change can tailor the nanogels to the specific applications. The build-up of structure-property relationship between functional nanogels and drug molecules provides fundamental knowledge for uptake/release of drug as well as other types of active components with nanogels. |
