Characterization of thermo and pH responsive NIPAM based microgels and their membrane blocking potential

Design, Synthesis, Characterization and Toxicity Studies of Poly (N-Iso- Propylacrylamide-co-Lucifer Yellow) Particles for Drug Delivery Applications

“…The DLS data suggest that LY was successfully incorporated in the new particle. The Figure also shows that the novel fluorescent nanoparticle maintains the reversible temperature responsive behaviour of p(NIPAM) with a VPTT comparable to that of 100% p(NIPAM) which is 35°C [3]. The polydispersity index (PdI) value ( Figure 5), which is close to zero (0.04), suggests that the majority of the particles in the dispersion acquire an even size.…”

“…The initial particle size at 15°C at pH 7 is 250 nm which is considerably smaller than that of 100% p(NIPAM) with an initial particle size of 550 nm [3,27]. The incorporation of a hydrophobic co-monomer such as lucifer yellow [28] decreases the extent of hydrogen bonding between the particle and water (solvent) compared to 100% p(NIPAM), so, less water will be incorporated in the particle leading to a smaller particle size [29].…”

“…The change in particle size is thought to be mainly attributed to the change of the protonation state of the co-monomer lucifer yellow by the change in pH (Figure 3). Several pH sensitive NIPAM based particles (with different comonomers such as acrylic acid) have been studied [3]. At pH lower than the pK a of the co-monomer, the anionic groups are protonated, accordingly, they are not charged and hence the electrostatic repulsion force is minimal.…”

“…The fact that the volume phase transition temperature (VPTT) of NIPAM based nanoparticles (32-34°C) [3] is very close to the human body temperature (37°C) makes them a good choice for biomedical applications. As an example of suggested drug delivery applications based on temperature trigger, the particles are swollen at room temperature (around 25°C which is below the VPTT), so, if they incorporate a drug in its matrix, when administered in the human body VPTT, it will deswell and release the drug.…”

“…Poly (N-isopropyl acrylamide) (p(NIPAM)) particles are characterised by their ability to change their conformation and physico-chemical properties (such as particle size and surface charge density) according to the change in the surrounding environment such as temperature, pH and ionic strength [1][2][3][4][5]. This is thought to be a property that can be used in different applications such as drug delivery [6].…”