Macromolecular Poly(N-isopropylacrylamide) (PNIPAM) in Cancer Treatment and Beyond

Poly(N-isopropylacrylamide) (PNIPAM) is a versatile polymer known for its phase transition properties, exhibiting a lower critical solution temperature (LCST) of approximately 32°C. Below this temperature, PNIPAM is hydrophilic, while above it, the polymer becomes hydrophobic, making it ideal for thermosensitive drug delivery systems (DDSs). In tissue engineering, PNIPAM provides a biocompatible, nontoxic and stimuli-responsive surface for cell culture. Its nontoxic nature ensures safety in medical applications. PNIPAM enhances biosensing diagnostics through its affinity for biomolecules, improving accuracy. Widely used in hydrogels, smart textiles, soft robotics and various medical applications, PNIPAM adapts to environmental changes. Its straightforward synthesis allows for the creation of diverse copolymers and composites, applicable in selective reactions and conjugations with fluorescent tags or chemical modifications. PNIPAM’s versatility extends to pH-responsive alternatives, broadening its application spectrum. Practical examples include phase separation in water treatment and cleaning processes. This discussion explores PNIPAM’s biomedical and drug delivery applications, particularly in cancer treatment, photothermal therapy (PTT) and photodynamic therapy (PDT), gene delivery and medical imaging. Additionally, it highlights PNIPAM’s noncancerous applications, such as small interfering RNA (siRNA) targeting of oncogenes and detailed imaging of deep and tumour tissues.