Gold nanorods-loaded chitosan-based nanomedicine platform enabling an effective tumor regression in vivo

Chitosan nanomedicines-engineered bifidobacteria complexes for effective colorectal tumor-targeted delivery of SN-38

The clinical application of 7-ethyl hydroxy-camptothecin (SN-38) maintains challenges not only due to its poor solubility and stability but also the lack of effective carriers to actively deliver SN-38 to deep tumor sites. Although SN-38-based nanomedicines could improve the solubility and stability from different aspects, the tumor targeting efficiency remains very low. Leveraging the hypoxic taxis of bifidobacteria bifidum (B. bifi) to the deep tumor area, we report SN-38-based nanomedicines-engineered bifidobacterial complexes for effective tumor-targeted delivery. Firstly, SN-38 was covalently coupled with poly-L-glutamic acid (L-PGA) and obtained soluble polymeric prodrug L-PGA-SN38 to improve its solubility and stability. To prolong the drug release, L-PGA-SN38 was mildly complexed with chitosan to form nanomedicines, and nanomedicines engineered B. bifi were further elaborated via electrostatic interaction of the excess of cationic chitosan shell from nanomedicines and anionic teichoic acid from B. bifi. The engineered B. bifi complexes inherited the bioactivity of native B. bifi and exhibited distinctly enhanced accumulation at the tumor site. More importantly, significantly elevated anti-tumor efficacy was achieved after the treatment of CS-L-PGA-SN38 NPs/B. bifi complexes, with favorable tumor suppression up to 80%. Such a B. bifi-mediated delivery system offers a promising platform for effective drug delivery and enhanced drug accumulation in the hypoxia deep tumor with superior anti-tumor efficacy.

Exploring the current landscape of chitosan-based hybrid nanoplatforms as cancer theragnostic

In the last decade, investigators have put significant efforts to develop several diagnostic and therapeutic strategies against cancer. Many novel nanoplatforms, including lipidic, metallic, and inorganic nanocarriers, have shown massive potential at preclinical and clinical stages for cancer diagnosis and treatment. Each of these nano-systems is distinct with its own benefits and limitations. The need to overcome the limitations of single-component nano-systems, improve their morphological and biological features, and achieve multiple functionalities has resulted in the emergence of hybrid nanoparticles (HNPs). These HNPs integrate multicomponent nano-systems with diagnostic and therapeutic functions into a single nano-system serving as promising nanotools for cancer theragnostic applications. Chitosan (CS) being a mucoadhesive, biodegradable, and biocompatible biopolymer, has emerged as an essential element for the development of HNPs offering several advantages over conventional nanoparticles including pH-dependent drug delivery, sustained drug release, and enhanced nanoparticle stability. In addition, the free protonable amino groups in the CS backbone offer flexibility to its structure, making it easy for the modification and functionalization of CS, resulting in better drug targetability and cell uptake. This review discusses in detail the existing different oncology-directed CS-based HNPs including their morphological characteristics, in-vitro/in-vivo outcomes, toxicity concerns, hurdles in clinical translation, and future prospects.