Chlorin e6 decorated doxorubicin encapsulated chitosan nanoparticles for photo-controlled cancer drug delivery.

In the study we have reported the physico-chemical, photophysical and morphological properties of chlorin e6 (Ce6) decorated doxorubicin (DOX) encapsulated chitosan (CS)-tripolyphosphate (TPP) nanoparticles which prepared by ionotropic gelation method. The Ce6 physically loaded onto the nanoparticles by self-assembly of CS with TPP-DOX under aqueous conditions. The results from DLS studies highlights the prepared nanoparticles that possess the size in the range of 80-120 nm. with negatively charged of -6 mV. The SEM and AFM images showed 80-120 nm size while the average size of the Ce6 decorated nanoparticles was found to be around 100-130 nm. The absorption spectra of Ce6 decorated nanoparticles are similar when compared to free Ce6 which suggest there is no change in the Ce6 chromophore upon decoration. This nanoparticle showed high photostability and singlet oxygen generation (SOG). The Ce6 decorated and DOX encapsulated nanoparticles sizes and charges are in the range of 90-130 nm and -30 mV respectively. The nanoparticles showed high encapsulation efficiency towards DOX as well as pH controlled release. This has significant anti-proliferative activity against MCF-7 breast cancer cells after irradiation at near infra-red (NIR) ranges were evaluated. This could have potential applications in photo-controlled smart DOX delivery system for cancer treatment.

Influence of functionalized nanoparticles on conformational stability of type I collagen for possible biomedical applications.

Collagen-nanoparticle interactions are vital for many biomedical applications including drug delivery and tissue engineering applications. Iron oxide nanoparticles synthesized using starch template according to our earlier reported procedures were functionalized by treating them with Gum Arabic (GA), a biocompatible polysaccharide, so as to enhance the interaction between nanoparticle surfaces and collagen. Viscosity, circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) techniques have been used to study the collagen-nanoparticle interactions. The relative viscosity for collagen-nanoparticle conjugate was found to increase with increase in concentration of the nanoparticle within the concentration range investigated, which is due to the aggregation of protein onto the surface of nanoparticle. The CD spectra for the collagen-nanoparticle at different concentration ratios do not have much variation in the Rpn values (ratio of positive peak intensity over negative peak intensity) after functionalization with GA. The variation of molar ellipticity values for collagen-nanoparticle is due to the glycoprotein present in GA. The collagen triple helical structure is maintained after interaction with nanoparticles. The FTIR spectra of native collagen, Coll-Fs (nanoparticle without functionalization) and Coll-FsG (nanoparticle functionalized with GA) show clearly the amide I, II, III bands, with respect to collagen. The ability of polysaccharide stabilized/functionalized nanoparticles to maintain the collagen properties would help in its biomedical applications.