IR 820 stabilized multifunctional polycaprolactone glycol chitosan composite nanoparticles for cancer therapy†

Photothermal therapy has gained worldwide attention for its less painful, non invasive/minimally invasive,
effective thermal ablation based therapy for cancer. It has been found to be effective in the treatment of
drug-resistant cancer. Currently available photothermal systems have several limitations such as a high
cost, incompatibility and clearance from the physiological system. To address these issues, we have
prepared multifunctional biocompatible and biodegradable cost effective IR 820 dye encapsulated glycol
chitosan coated polycaprolactone composite nanoparticles (PCLGC–IR) with improved performance.
Polycaprolactone (PCL) has been used as a cheap biodegradable polymer, glycol chitosan (GC) as an
immunoadjuvant for immune response generation followed by the cost-effective IR 820 dye for
photothermal therapy. IR 820 encapsulation increases the stability of the PCLGC–IR nanoparticles as
confirmed by DSC and XRD, while the glycol chitosan enhances the uptake of the composite
nanoparticles by MDA-MB-231 breast cancer cells. The PCLGC–IR composite nanoparticles with a size
of around 150–200 nm can be irradiated with a dual laser at 750 nm and 808 nm in photothermal
therapy (PTT). In addition to PTT, the PCLGC–IR composite nanoparticles can also be used for
sustainable controlled drug release as they retain their structural integrity even after laser treatment.
Further we analyzed the degraded product using liquid chromatography mass spectroscopy (LCMS)
upon photo irradiation. A cytotoxicity study of the PCLGC–IR composite nanoparticles was carried out
on NIH3T3 cells. Fluorescence microscope image analysis of MDA-MB-231 cells showed hyperthermic
cell death via apoptosis and necrosis due to an enhanced uptake of the PCLGC–IR composite
nanoparticles. Our results showed that this nanoformulation can be used for the effective treatment ofmultiple drug resistant cancer.