Site-Specific Amphiphilic Magnetic Copolymer Nanoaggregates for Dual Imaging

Abstract

Molecular imaging along with combinations of imaging modalities can provide a thorough understanding of disease, in particular, tumors. Magnetic resonance imaging (MRI) offers exceptional tissue contrast and resolution; whereas optical imaging provides high sensitivity. Hence a norbornene based copolymer (Nor-Cob-Py-Fol) is reported in this paper as a dual-imaging agent. Nor-Cob-Py-Fol having Co2+ complex, pyrene and poly­(ethylene glycol) derived folate, have been synthesized using ring-opening metathesis polymerization (ROMP). All the monomers and polymers are characterized by 1H NMR, IR, GPC, and TGA techniques. The morphology of the copolymer nanoaggregates has been evaluated with DLS, TEM, and SEM techniques. The functionalization of Co2+ to the polymer is monitored by FTIR, 1H NMR, and 13C NMR spectroscopy. Furthermore, the presence of Co2+ in the nanoaggregates is confirmed by the EDX (SEM) technique. To prove the MRI capabilities nature of copolymer nanoaggregates, NMR experiment is performed at room temperature. Cell viability studies suggest the biocompatibility nature of the copolymer. Flow cytometry as well as epifluoroscence microscope experiments clearly demonstrate the dual-imaging ability of the newly designed copolymer. The much higher relaxivity ratio (r 2/r 1) of the present method clearly establishes the superiority of our system as one of the best contrast agents known to the practitioners of magnetic resonance imaging.

Supramolecular Behaviour and Fluorescence of Rhodamine-Functionalised ROMP Polymer

“…Typically in fluorophore-functionalised ROMP polymers, fluorescent monomers are copolymerised with monomers that provide different imaging functionalities such as MRI contrast. 48,49 When copolymerised, the fluorescent monomers tend to undergo quenching to varying degrees and this can be caused by several phenomena including aggregation-caused quenching (ACQ) 50 and chemical interaction with other functional groups. [51][52][53] In the system reported here, since the hydrophobic block is formed from just one monomer, it is possible for quenching or other photophysical interactions to occur both at intra-and interchain levels.…”

Polymer based Nano-Assemblies: Very Efficient Carrier in the Field of Cancer Chemotherapy

“…Grubbs' catalyst with its three different generation ruthenium catalysts can open the norbornene ring with different complex architecture which eventually help to tune the different properties of the biocompatible nano-carrier [13]. Theranostic systems or site specific dual imaging motifs generally requires of anchoring different complex synthetic molecules into a single system to tune the properties and metathesis polymerization technique serve it excellently [7,17,19]. By this method different nano-mater aggregated structure can be formed with different imaging motif and drug attached to it by variety of stimuli responsive linker or encapsulation [7,15,17].…”

“…Theranostic systems or site specific dual imaging motifs generally requires of anchoring different complex synthetic molecules into a single system to tune the properties and metathesis polymerization technique serve it excellently [7,17,19]. By this method different nano-mater aggregated structure can be formed with different imaging motif and drug attached to it by variety of stimuli responsive linker or encapsulation [7,15,17]. The functional group tolerant Grubbs' catalyst can polymerize a variety of monomers bearing complex motif or inorganic metal and thus we can tune the loading by simply fine tuning the degree of polymerization (DP) [13,17].…”

“…By this method different nano-mater aggregated structure can be formed with different imaging motif and drug attached to it by variety of stimuli responsive linker or encapsulation [7,15,17]. The functional group tolerant Grubbs' catalyst can polymerize a variety of monomers bearing complex motif or inorganic metal and thus we can tune the loading by simply fine tuning the degree of polymerization (DP) [13,17].…”

“…nanoparticles, peptides, dendrimer, and liposomes) have been explored by the researchers which efficiently carries the drug to the targeted sites [4]. These all particularly form excellent nano-assemblies in aqueous environment due its amphiphilicity present in it [14][15][16][17][18]. Polymer based drug delivery system is one of those which form excellent nano-assemblies when it functionalized with hydrophilic PEG group [7,9,[11][12][13].…”