Light-triggered smart materials

In most cases, the as-obtained nanocarriers can release the loaded biomolecules in response to only one kind of external stimulus, such as light, pH, or temperature, and realize a monoresponsive nanochannel. However, the sensitivity of these nanocarriers is not very efficient. Even for NIR-triggered phototherapy, the effective penetration depth of NIR light is still limited to no more than 1 cm and its sensitivity and accuracy to treat tumors located deep inside the body is thus limited. Therefore, delivery systems triggered by at least two different inputs have recently been considered by researchers. Generally, in order to get dual-responsive nanocarriers, two kinds of smart materials or one material with two functional groups must be included in the same NP. For example, two kinds of responsive materials, such as PAA and PNIPAm, can be simultaneously employed in the a pH- and... 

The examples mentioned above relied on hydrophobic collapse of one of the blocks of the block copolymer upon addition of a nonsolvent. There are numerous cases of linear block copolymer systems where one of the blocks is tunable, with switchable hydrophilicity in response to changes in external stimuli such as pH, temperature, light,or a combination of conditions. These stimuli-responsive polymers are sometimes referred to as smart polymers and possess immense potential in biomedical applications because of their ability to assemble/disassemble in response to artifidal or biologically triggered events. Although not discussed expli-dtly in this chapter, some of the materials described exhibit stimuli-responsive characteristics those and other polymers are... 

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