Brannon-Peppas theory of swelling in ionic hydrogels Original theory for elastic networks developed by Flory and Mehrer, refined for treatment of ionic hydrogels by Brannon-Peppas and Peppas Other theoretical treatments Derivation of ionic hydrogel swelling Model structure of the system

Molecular switches in the cell: fibronectin as a mechanical switch (vogel, 2002) Fibronectin is an adhesion protein secreted by cells and assembled into fibrils to support adhesion and migration Composed of\ of fibronectin repeats Fnl, Fnll, and Fnlll connected by short linkers of varying flexibility One particular Fnlll repeat, Fnlll10

molecular switches Proteins as motors in nanodevices Today. nano-and micro-particle drug carriers Reading D A Hammer and D.E. Discher, ' Synthetic cells- Self-assembling polymer membranes and bioadhesive colloids, Annu. Rev. Mater Res, 31, 387-404 (2001) Nano- and Micro-scale Drug Carriers and Detection Reagents Nano- to Micro-particle polymer-protein

Lecture 16: Intracellular drug delivery Last time nano- and micro-particle drug carriers Delivery to tissues from systemic circulation Today. Intracellular drug delivery Reading A.S. Hoffman et aL., Design of \smart polymers that can direct intracellular drug delivery, Polym. Adv. Technol. 13, 992-999(2002) Ph gradients and drug delivery: cancer res. 56, 1194(1996): adv drug deliv rev 25, 3 (1997); see asokan minireview

Lecture 19: Biosensors(continued ast time: biosensor device cla Gene array biosensor Today detection methods Detection Elements Macroscopic fluorescence, diffraction, or interference ·what Example: quantum dot-loaded microsphere capture agents QDs show size-dependent luminescence Narrow emission bands from a common excitation wavelength

engineering intracellular delivery Drug targeting Today biosensor device classes Detection methods Overview of biosensor technology Classes of biosensor devices External analysis/detection

Biodegradable Solid Polymers Spring 2003 Issued Day 1 Day 3 1. The chemical structure of a new degradable polymer, poly (ethylene glycol)-b-polylysine-b- poly (D, L-lactide)

1. (4 pts) An early study in the development of peptide-presenting biomaterials showed that polymer surfaces bearing RGD peptides at a density equivalent to -10 peptides per each cell was sufficient to promote cell attachment, spreading and subsequent cell growth. In contrast, when whole fibronectin protein was adsorbed to polymer surfaces, it was found that many more copies of the

A recent study of controlled release of a model small-molecule drug from poly (lactide-co-glycolide) microspheres prepared by the single-emulsion method found that the diffusion constant of the drug through the polymer was best related to the polymer's molecular weight according to

1. Re-derive the equation for equilibrium swelling of a polyelectrolyte gel where the polymer chains contain a basic ionizable group that becomes positively charged with decreasing pH