Publications by authors named "Kalyan Ramesh"

In this study, diselenide (Se-Se) and disulfide (S-S) redox-responsive core-cross-linked (CCL) micelles were synthesized using poly(ethylene oxide)--poly(furfuryl methacrylate) (PEO--PFMA), and their redox sensitivity was compared. A single electron transfer-living radical polymerization technique was used to prepare PEO--PFMA from FMA monomers and PEO-Br initiators. An anti-cancer drug, doxorubicin (DOX), was incorporated into PFMA hydrophobic parts of the polymeric micelles, which were then cross-linked with maleimide cross-linkers, 1,6-bis(maleimide) hexane, dithiobis(maleimido) ethane and diselenobis(maleimido) ethane via Diels-Alder reaction.

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For many cancer types, being undetectable from early symptoms or blood tests, or often detected at late stages, medical imaging emerges as the most efficient tool for cancer screening. MRI, ultrasound, X-rays (mammography), and X-ray CT (CT) are currently used in hospitals with variable costs. Diagnostic materials that can detect breast tumors through molecular recognition and amplify the signal at the targeting site in combination with state-of-the-art CT techniques, such as dual-energy CT, could lead to a more precise detection and assist significantly in image-guided intervention.

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In the present study, we developed near-infrared (NIR)-responsive shell-crosslinked (SCL) micelles using the Diels-Alder (DA) click reaction between an amphiphilic copolymer poly(d,l-lactide)--poly((furfuryl methacrylate)--(-acryloylmorpholine)) (PLA--P(FMA--NAM)) and a diselenide-containing crosslinker, bis(maleimidoethyl) 3,3'-diselanediyldipropionoate (BMEDSeDP). The PLA--P(FMA--NAM) copolymer was synthesized by RAFT polymerization of FMA and NAM using a PLA-macro-chain transfer agent (PLA-CTA). The DA reaction between BMEDSeDP and the furfuryl moieties in the copolymeric micelles in water resulted in the formation of SCL micelles.

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Article Synopsis
  • The study investigates how the porosity of alginate hydrogels affects drug release, with two different formulations created using distinct crosslinkers.
  • The results revealed that the porous hydrogel (Alg-Nb) allowed for faster drug release due to its adjustable porosity, while the non-porous hydrogel (Alg-FA) released drugs slowly.
  • Notably, the porous hydrogels demonstrated the ability to sustainably release the drug doxorubicin over a period of 35 days.
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The beguiling world of functional polymers is dominated by thermoresponsive polymers with unique structural and molecular attributes. Limited work has been reported on the protein-induced conformational transition of block copolymers; furthermore, the literature lacks a clear understanding of the influence of proteins on the phase behavior of thermoresponsive copolymers. Herein, we have synthesized poly(-isopropylacrylamide)--poly(-vinylcaprolactam) (PNIPAM--PNVCL) by RAFT polymerization using -isopropylacrylamide and -vinylcaprolactam.

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Owing to their unique topology and physical properties, micelles based on miktoarm amphiphilic star block copolymers play an important role in the biomedical field for drug delivery. Herein, we developed a series of AB-type poly(D,L-lactide-co-glycolide)-b-poly(-acryloyl morpholine) (PLGA-b-PNAM) miktoarm star block copolymers by reversible addition-fragmentation chain-transfer polymerization and ring-opening copolymerization. The resulting miktoarm star polymers were investigated by H NMR spectroscopy and gel permeation chromatography.

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We have synthesized a well-defined four-arm star amphiphilic block copolymer [poly(DLLA)-b-poly(NVP)]4 [star-(PDLLA-b-PNVP)4] that consists of D,L-lactide (DLLA) and N-vinylpyrrolidone (NVP) via the combination of ring-opening polymerization (ROP) and xanthate-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization. Synthesis of the polymer was verified by 1H NMR spectroscopy and gel permeation chromatography (GPC). The amphiphilic four-arm star block copolymer forms spherical micelles in water as demonstrated by transmission electron microscopy (TEM) and 1H NMR spectroscopy.

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