Lawsonia inermis-organically modified chitosan intercalated bentonite clay: A multifunctional nanotheranostic system for controlled drug delivery, sensing and cellular imaging

This study presents the development of organo-bentonites (OBs); a cost-effective drug delivery system holding both sensing and imaging capabilities. The OBs were synthesized using quaternary ammonium cations derived from chitosan, Lawsonia inermis, and pyrene/anthracene carboxaldehyde combinations through a three-step process: Mannich reaction, quaternization, and intercalation. Physicochemical characterization confirms the organic modification of bentonite. The OBs: NQPB and NQAB hold substantial ciprofloxacin (Cipro) loading capacities (71.51 % and 78.04 %, respectively) and exhibit pH-dependent release profiles, suggesting their potential use as drug delivery platforms. Cell viability evaluation by MTT and live-dead assays indicates favourable results. Both OBs demonstrate fluorescence within the 450-500 nm range, and they display concentration-dependent fluorescence quenching and enhancement for NQPB and NQAB, respectively, in the presence of tryptophan (Trp), making them suitable for its detection. Confocal analysis further enunciates the live intracellular fluorescence upon OB uptake. In summary, the intrinsically fluorescent mesoporous OBs synthesized from Lawsonia inermis and chitosan exhibit multifunctionality, including Cipro delivery, Trp sensing, and live cell imaging. Among the OBs, NQAB could be considered as a promising theranostic platform owing to its superior cytocompatibility (>80 %), appreciable fluorescence, and controlled release profile.