Poly(N-isopropylacrylamide)
Encyclopedia
Poly (variously abbreviated PNIPA, PNIPAAm, PNIPAA or PNIPAm) is a temperature-responsive polymer that was first synthesized in the 1950s. It can be synthesized from NIPAM which is commercially available.
It forms a three-dimensional hydrogel when crosslinked with N,N’-methylene-bis-acrylamide (MBAm) or N,N’-cystamine-bis-acrylamide (CBAm). When heated in water above 32°C, it undergoes a reversible lower critical solution temperature
phase transition from a swollen hydrated state to a shrunken dehydrated state, losing about 90% of its mass
. In dilute solution, it undergoes a corresponding coil-to-globule transition
at similar conditions).. Since PNIPAm expels its liquid contents at a temperature near that of the human body, PNIPAm has been investigated by many researchers for possible applications in tissue engineering and controlled drug delivery
. The renal glomerular filtration cut-off of copolymers of PNIPAm is situated around 32,000 g/mol.
It forms a three-dimensional hydrogel when crosslinked with N,N’-methylene-bis-acrylamide (MBAm) or N,N’-cystamine-bis-acrylamide (CBAm). When heated in water above 32°C, it undergoes a reversible lower critical solution temperature
Lower critical solution temperature
The lower critical solution temperature or lower consolute temperature is the critical temperature below which the components of a mixture are miscible for all compositions...
phase transition from a swollen hydrated state to a shrunken dehydrated state, losing about 90% of its mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
. In dilute solution, it undergoes a corresponding coil-to-globule transition
Coil-globule transition
In polymer physics, the Coil-globule transition is the collapse of a macromolecule from an expanded coil state through an ideal coil state to a collapsed globule state, or vice-versa. The coil-globule transition is of importance in biology due to the presence of coil-globule transitions in...
at similar conditions).. Since PNIPAm expels its liquid contents at a temperature near that of the human body, PNIPAm has been investigated by many researchers for possible applications in tissue engineering and controlled drug delivery
Drug delivery
Drug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals. Drug delivery technologies modify drug release profile, absorption, distribution and elimination for the benefit of improving product efficacy and safety, as well...
. The renal glomerular filtration cut-off of copolymers of PNIPAm is situated around 32,000 g/mol.