title: Targeted Smart pH and Thermoresponsive N,O-Carboxymethyl Chitosan Conjugated Nanogels for Enhanced Therapeutic Efficacy of Doxorubicin in MCF-7 Breast Cancer Cells.
abstract: In cancer treatment, developing ideal anticancer drug delivery systems to target tumor microenvironment by circumventing various physiological barriers still remains a daunting challenge. Here, in our work, a series of pH- and temperature-responsive nanogels based on poly(N-isopropylacrylamide-co-1-propene-2-3-dicarboxylate-co-2-acrylamido-2-methyl-1-propanesulfonate [poly(NIPAAm-IA-AMPS)] cross-linked by ethylene glycol dimethacrylate (EGDMA) were synthesized by random copolymerization. The molar ratio between monomer-comonomers-cross-linker was varied to fine-tune the optimum responsiveness of the nanogels. These optimized nanogels were further coupled to N,O-carboxymethyl chitosan (NOCC) stoichiometrically using EDC-NHS coupling chemistry to enhance the swelling behavior at lower pH. Interestingly, these NOCC-g-nanogels, when dispersed in aqueous media under sonication, attain nanosize and retain their high water-retention capacity with conspicuous pH and temperature responsiveness (viz. nanogel shrinkage in size beyond 35 °C and swelled at acidic pH) in vitro, as reflected by dynamic light scattering data. Doxorubicin (DOX), a potent anticancer drug, was loaded into these nanogels using the physical entrapment method. These drug-loaded nanogels exhibited a slow and sustained DOX release profile at physiological temperature and cytosolic pH. Furthermore, confocal and TEM results demonstrate that these nanogels were swiftly internalized by MCF-7 cells, and cell viability data showed preferential heightened cytotoxicity toward cancer cells (MCF-7 and MDA-MB231) compared to the MCF10A cells (human breast epithelial cell). Furthermore, intracellular DNA damage and cell cycle arrest assays suggest a mitochondrial mediated apoptosis in MCF-7 cells. This study substantiates our NOCC-g-nanogel platform as an excellent modality for passive diffusive loading and targeted release of entrapped drug(s) at physiological conditions in a controlled way for the improved therapeutic efficacy of the drug in anticancer treatment.
authors.affiliation: Water Analysis Laboratory, Nanotherapeutics & Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR) , Vishvigyan Bhawan, 31 Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.|College of Dental Sciences, BBD University , Faizabad Road, Lucknow 226028, Uttar Pradesh, India.
authors.forename: Neeraj K
authors.initials: NK
authors.lastname: Verma
authors.affiliation: Water Analysis Laboratory, Nanotherapeutics & Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR) , Vishvigyan Bhawan, 31 Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.|Academy of Scientific and Innovative Research (AcSIR) , CSIR-IITR Campus, Lucknow 226001, Uttar Pradesh, India.
authors.forename: Mahaveer P
authors.initials: MP
authors.lastname: Purohit
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute (CSIR-CDRI) , Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India.
authors.forename: Danish
authors.initials: D
authors.lastname: Equbal
authors.affiliation: Water Analysis Laboratory, Nanotherapeutics & Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR) , Vishvigyan Bhawan, 31 Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.|Academy of Scientific and Innovative Research (AcSIR) , CSIR-IITR Campus, Lucknow 226001, Uttar Pradesh, India.
authors.forename: Nitesh
authors.initials: N
authors.lastname: Dhiman
authors.affiliation: Water Analysis Laboratory, Nanotherapeutics & Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR) , Vishvigyan Bhawan, 31 Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.
authors.forename: Amrita
authors.initials: A
authors.lastname: Singh
authors.affiliation: Water Analysis Laboratory, Nanotherapeutics & Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR) , Vishvigyan Bhawan, 31 Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.|Academy of Scientific and Innovative Research (AcSIR) , CSIR-IITR Campus, Lucknow 226001, Uttar Pradesh, India.
authors.forename: Aditya K
authors.initials: AK
authors.lastname: Kar
authors.affiliation: Water Analysis Laboratory, Nanotherapeutics & Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR) , Vishvigyan Bhawan, 31 Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.
authors.forename: Jai
authors.initials: J
authors.lastname: Shankar
authors.affiliation: Department of Chemistry, Motilal Nehru College, University of Delhi South Campus , Benito Juarez Road, South Campus, New Delhi 110021, Delhi, India.
authors.forename: Sarita
authors.initials: S
authors.lastname: Tehlan
authors.affiliation: Water Analysis Laboratory, Nanotherapeutics & Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR) , Vishvigyan Bhawan, 31 Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.|Academy of Scientific and Innovative Research (AcSIR) , CSIR-IITR Campus, Lucknow 226001, Uttar Pradesh, India.
authors.forename: Satyakam
authors.initials: S
authors.lastname: Patnaik
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D017209:Apoptosis / Q000187:drug effects; D001692:Biological Transport; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D004249:DNA Damage; D004317:Doxorubicin / Q000737:chemistry* / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry* / Q000378:metabolism; D005782:Gels; D006801:Humans; D006863:Hydrogen-Ion Concentration; D061986:MCF-7 Cells; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D049329:Nanostructures / Q000737:chemistry*; D018384:Oxidative Stress / Q000187:drug effects; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D004337:Drug Carriers; D005782:Gels; C077199:O,N-carboxymethylchitosan; C052970:poly-N-isopropylacrylamide; D004317:Doxorubicin; D048271:Chitosan