Cellulose-Derived Carbon Dots for Inner Filter Effect-Based Selective Sensing of Ofloxacin Antibiotics

Abstract

A two-step viable synthetic approach for quick and energy-efficient acid-based charring is described here to fabricate self-passivated fluorescent water-soluble CD (wsCD) from sustainable microcrystalline cellulose (MCC) materials. The aqueous solution of wsCD exhibits blue emission under UV-light illumination and shows a fluorescence quantum yield of ∼6%. The wsCD are used here for the selective sensing of ofloxacin (OFLX) from among the four tested antibiotics of the fluoroquinolone class, namely, ciprofloxacin (CPLX), ofloxacin (OFLX), levofloxacin (LVLX), and moxifloxacin (MXLX) based on the simpler fluorescence quenching experiment with a detection limit of ∼0.025 ppm. The plausible mechanism for the selective sensing of OFLX has been proposed based on a detailed analysis of absorbance and time-resolved photoluminescence spectroscopy which indicates the involvement of the inner-filter effect (IFE). Antimicrobial studies of wsCD were conducted on two bacterial strains (Escherichia coli and Staphylococcus aureus) and two fungal strains (Aspergillus niger and Penicillium chrysogenum), where wsCD did not show any toxic effects up to the concentration of 1 mg/mL, hence supporting their biocompatible behavior. Further, an antibiosis study involving the combination of the antibiotic and antifungal agents with wsCD against the growth of the same bacterial and fungal strains was conducted, where wsCD showed mild antifungal activity.

3D Porous MoS2-Decorated Reduced Graphene Oxide Aerogel as a Heterogeneous Catalyst for Reductive Transformation Reactions

“…The short scan analysis of respective elements was also performed to understand the elemental binding in MoS 2 -rGOA. The short scan spectra of C 1s show peaks at ∼284.5, ∼285.2, ∼287.0, and ∼289.2 eV, which corresponds to the CC, C–O, CO, and −C­(O)–O bonds, as shown in Figure c. , The deconvoluted spectra of O 1s show peaks allocated at ∼531.3 and ∼533.2 eV that arises due to CO and C–O bonds, respectively (Figure d) . However, Figure e represents the deconvoluted spectra of S 2p, which shows peaks at ∼163.6, ∼164.8, and ∼168.5 eV that can arise due to the presence of S 2p 3/2 , S 2p 1/2 , and S–O bonds.…”

“…The short scan analysis of respective elements was also performed to understand the elemental binding in MoS 2 -rGOA. The short scan spectra of C 1s show peaks at ∼284.5, ∼285.2, ∼287.0, and ∼289.2 eV, which corresponds to the C�C, C−O, C�O, and −C(O)−O bonds, as shown in Figure1c.47,48 The deconvoluted spectra of O 1s show peaks allocated at ∼531 3.…”

Nitrogen-Doped Carbon Nanoflakes by Acidic Charring of Microcrystalline Cellulose and Urea for the Rapid Removal of Imidacloprid from Water

“…The synthesis of N-CNF from microcrystalline cellulose (MCC) (carbon source) and urea (nitrogen source) is shown in Scheme . The method of acid-assisted carbonization was used for the dehydration, polymerization, and aromatization, , along with in situ doping of nitrogen in a graphitic carbon framework. , After thermal treatment of a mixture of MCC and urea, the reaction was quenched and neutralized using excess DI water, and the obtained black carbonized material was named nitrogen-doped carbon nanoflakes (N-CNF) (Scheme ).…”

N-doped graphene nanosheets-based optical nano switch for the selective detection of guanine and Pb2+

“…The change in the local density of states was also evident for the same. 60,61 A plausible mechanistic explanation for the uorescence quenching through the ws-NGNSs/Pb 2+ system is demonstrated in Fig. 5a.…”