Thermoresponsive [(PLA)-co-(Car)] based frustum-shaped capsules with extended porosity for biosensing and biomedical applications

We present, a facile method for the synthesis of block co-polymer (BCP) of [(PLA)-b-(Car)], (PLA-Poly Lactic acid and Car-Carbazole). BCP results in the design and development of cone and ice-cream cup-shaped frustums with nanoscale porosity for bio-sensing and drug delivery applications. [(PLA)-b-(Car)] was conjugated through condensation polymerization between amine proton and hydroxyl groups of PLA and Car. Thermoplastic PLA is responsible for desired size, shape, and porosity over the surface. The size, shape, and morphology of the [(PLA)-b-(Car)] are tunable based on suitable solvents and thermal treatment. Interestingly, design of nanoporous hollow (half-broken coconut type) capsules has been carried out without using any precursors and surfactants. Synthesis of [(PLA)-b-(Car)] has been confirmed through the Fourier transform infrared (FTIR), nuclear magnetic resonance (¹H NMR). However, the morphology and surface properties of capsules were confirmed through field emission scanning electron microscopy (FE-SEM), Bruner Emmett Teller (BET), and atomic force microscopy (AFM) characterizations. The capsule size ranges from ~ 200 nm to 1 μm (in diameter) and porosity scales from ~ 60 to 80 nm. The hollow and porous surface of the capsules with biosensing and drug delivery applications can be considered as a unique and novel characteristic property of our invention. This kind of novel cone and ice cream cup-shaped hollow frustums can be used as a stimuli-responsive catalytic activity through the fluorescence measurement of cysteine and gold nanoparticle [(Cys)-(Au⁺)] for enhanced payload and biomedical applications.