Carbon dot embedded hybrid microgel from synthesis to sensing: Experimental and theoretical approach

The intellectual progress in fabricating artificial probes for selective appraisal of biologically admissible amino acids has displayed exponential growth in recent era.The neoteric era in material science has witnessed the significant application of carbon quantum dots (CQDs). However, the hybrid microgel of CQDs was less explored. Herein, a highly fluorescent hybrid microgel for Tryptophan (Trp) sensing has been successfully prepared by in-situ addition of biocompatible carbon dots (CQDs) with poly-N isopropylacrylamide (PNIPAM). This bio-probe was successfully prepared by precise control over the size and shape of CQDs by effective surface passivation with PNIPAM. This inventive methodology facilitates the accurate and selective recognition of Trp. The operative features such as concentration, pH and temperature of this process were optimized to establish integrity, sensitivity, selectivity and efficiency towards Trp. The integrated hybrid microgel was effectively useful for the quantification of Trp with a wide linear range of 10 μM-500 μM, with a limit of detection as low as 0.1 μM. Significance: The current integrated system displayed desirable selectivity in the presence of comparable bio-molecules illustrating its booming performance towards Trp sensing. Further advancing the performance of developed sensor, the application of this strategy was extended for selective recognition of Trp in presence of various real water samples from different sources. The combining effect of high biocompatibility and fluorescent property of CQDs with thermo-responsive behaviour of PNIPAM provide smart hybrid gels with intriguing potential in diagnosis and hold remarkable potential in practical applications including healthcare and environmental remediation application. The integrated hybrid microgel was effectively useful for the quantification of Trp with a wide linear range of 10 μM–500 μM, with a limit of detection as low as 0.121 μM. [Display omitted] •CQDs embedded fluorescent microgels of PNIPAM was developed.•Biocompatibility studies have been performed.•Developed sensor was effective to sense tryptophan with LOD of 0.121 μM.•DFT simulations are performed to sensing mechanism.