%0 Journal Article
%T Bioresponsive matrices in drug delivery
%A Jin-Oh You
%A Dariela Almeda
%A George JC Ye
%A Debra T Auguste
%J Journal of Biological Engineering
%D 2010
%I BioMed Central
%R 10.1186/1754-1611-4-15
%X Polymeric materials that respond to a stimulus are often called "smart" or "intelligent" due to their intrinsic ability to alter their physical or chemical properties. For the majority of the polymers that fall into this category, the response to a change in the surrounding environment is not only quick, on the order of minutes [1,2] to hours [3,4], but also reversible, mimicking the dynamics observed in natural polymers, such as proteins, polysaccharides, and nucleic acids in living organic systems [5]. The response to stimuli is manifested in many forms: individual chain dimension/size, shape, surface characteristics, secondary structure, solubility, and degree of intermolecular association. These unique capabilities have been applied to a diverse range of applications, including: drug delivery [4,6-8], diagnostics [9,10], biological coating technologies [11,12], biosensing [10,13], and microfluidics [14].Conventional drug delivery methods physically entrap molecules within a polymer lattice; drug is released slowly by diffusion or upon degradation of the network. These methods typically result in an early peak in plasma drug concentration followed by a steady, linear release. This is far from ideal because the local drug concentration and location of delivery is not precisely controlled. Below the therapeutic dose, the drug is ineffective whereas high concentrations of drug may be toxic or lead to undesirable side effects. Polymers have been used to tailor drug release, which maintains the drug concentration within the desired therapeutic range. However, such controlled release systems are insensitive to metabolic changes in the body and are unable to modulate drug release nor target the drug to diseased tissue. This lack of control has motivated the exploitation of bioresponsive polymers as drug carriers.As early as the 1950 s, stimuli responsive hydrogels have been studied for drug release [15]. Since then, polymers that react to different stimuli have been dev
%U http://www.jbioleng.org/content/4/1/15