Self-Reporting Polysaccharide Polymersome for Doxorubicin and Cisplatin Delivery to Live Cancer Cells

Abstract

We report self-reporting fluorescent polysaccharide polymersome nanoassemblies for enzyme-responsive intracellular delivery of two clinical anticancer drugs doxorubicin (DOX) and cisplatin to study the real-time drug-releasing aspects by fluorescent resonance energy transfer (FRET) bioimaging in live cancer cells. Fluorescent polymersomes were tailor-made by tagging an aggregation-induced emission (AIE) optical chromophore, tetraphenylethylene (TPE), and a plant-based vesicular directing hydrophobic unit through enzyme-biodegradable aliphatic ester chemical linkages in the polysaccharide dextran. The blue-luminescent polymersome self-assembled in water and exhibited excellent encapsulation capability for the red-luminescent anticancer drug DOX. FRET between the AIE polymersome host and DOX guest molecules resulted in a completely turn-off probe. At the intracellular level, the lysosomal enzymatic disassembly of the polymersome restored the dual fluorescent signals from DOX and TPE at the nucleus and the lysosomes, respectively. Live-cell confocal microscopy coupled with selective photoexcitation was employed to study the real-time polymersome disassembly by monitoring the turn-on fluorescent signals in human breast cancer cell lines. Alternatively, carboxylic acid-functionalized AIE polymersomes were also tailor-made for cisplatin stitching to directly monitor Pt drug delivery. The polymersome nanoassemblies exhibited excellent structural tolerance for the chemical conjugation of the Pt drugs, and the fluorescence signals were unaltered. An in vitro drug release study confirmed that the cisplatin-stitched fluorescent polymersomes were very stable under physiological conditions and underwent lysosomal enzymatic degradation to inhibit the cancer cell growth. A lysosomal colocalization experiment using confocal microscopy substantiates the enzyme-responsive degradation of these polymersomes to release both the encapsulated and conjugated drugs at the intracellular level. The present design provides a unique opportunity to deliver more than one anticancer drug from a single polymersome platform in cancer research.

l-Amino Acid Based Phenol- and Catechol-Functionalized Poly(ester-urethane)s for Aromatic π-Interaction Driven Drug Stabilization and Their Enzyme-Responsive Delivery in Cancer Cells

“…After polycondensation, a multiplet at 4.08 (proton b + b′) appeared in polymer NMR with respect to new ester and urethane chemical linkages. The comparison of peaks in the 13 C NMR spectrum of monomer 2 and the polymer revealed the disappearance of end groups and appearance of the newly formed ester and urethane peaks. Similarly, the melt polymerization of L-tyrosine monomer 2 with other diols was confirmed in Figures S4 and S5.…”

“…1 H NMR (400 MHz, CDCl 3 ) δ ppm: 0.19 (s, 12 H, -Si(CH 3 ) 4 ), 0.98 (s, 18 H, -Si-C(CH 3 ) 6 ), 2.98 (d, 2 H, -CH-CH 2 ), 3.67 (s, 3 H, -NH-COOCH 3 ), 3.71 (s, 3 H, -COOCH 3 ), 4.56 (q, 1 H, -NH-CH), 5.11 (d, 1 H, CH-NH), 6.53−6.56 (dd, 1 H, ArH), 6.60 (d, 1 H, ArH), 6.74 (d, 1 H, ArH). 13 Synthesis of the L-Tyrosine Based Silylated Polymer. A typical procedure for polymer PTyr-Si-12 is described.…”

“…Prodrug-gated cross-linked vesicles, coumarin and Nile blue conjugated polymeric vesicles, and disulfide bond-tethered polyprodrug amphiphiles were some of the important examples reported for cascade photothermal chemotherapy, fluorescent imaging, etc. From our laboratory, dextran-based polymersomes were reported for DOX and CPT to accomplish synergistic combination therapy. , Often, cross-talking between π-conjugated chromophores in the polymer chains and the encapsulated polyaromatic drug molecules was exploited to construct fluorescence resonance energy transfer (FRET) probes to gain an in-depth understanding both in vitro and in vivo . − However, majority of the π-conjugated chromophores employed for the above purpose limits the biodegradability due to their extended C–C backbone, and therefore, the undesirable cytotoxicity associated with these π-conjugated species under physiological conditions is still a major concern in biomedical research. One of the elegant strategies to overcome the above limitation is by choosing bio-derived and biocompatible aromatic systems as polymerizable monomers and exploring the resultant macromolecular system to facilitate the π–π interaction driven drug encapsulation and stabilization in cancer research.…”

“…NMR and13 C NMR of synthesized compounds and polymers, TGA, DSC data of polymers, water contact angle images of polymers, DLS data, and TEM images (PDF)■AUTHOR INFORMATION Corresponding Author Manickam Jayakannan − Department of Chemistry, Indian Institute of Science Education and Research (IISER Pune), Pune 411008 Maharashtra, India; orcid.org/0000-0001-7699-2016; Email: jayakannan@iiserpune.ac.in Authors Dheeraj Chandra Joshi − Department of Chemistry, Indian Institute of Science Education and Research (IISER Pune), Pune 411008 Maharashtra, India Akash Ashokan − Department of Chemistry, Indian Institute of Science Education and Research (IISER Pune), Pune 411008 Maharashtra, India…”

Stimuli-Responsive Aggregation-Induced Emission (AIE)-Active Polymers for Biomedical Applications

“…Recently, Jayakannan and his group have reported a fluorescence resonance energy transfer (FRET)-based self-reporting polysaccharide polymersome for studying the enzyme-responsive intracellular real-time drug releasing aspect. , First, a polysaccharide derivative was synthesized by grafting the TPE unit and a plant-based vesicular directing hydrophobic unit through ester linkages on the polysaccharide dextran. The resulting polysaccharide derivative was self-assembled in water to polymersome with blue light emission and encapsulated red light emissive anticancer drug DOX.…”