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Water-soluble silver nanoclusters (AgNCs) as a new type of fluorescent material have attracted much attention for their remarkable optical properties and excellent cytocompatibility. However, it is still challenging to synthesize water-soluble AgNCs with good cytocompatibility and excellent fluorescence. Herein, the dialdehyde nanofibrillated cellulose (DANFC)- reduced water-soluble AgNCs capped by glutathione (GSH) with tunable fluorescence emissions were first reported. The DANFC provides a mild reduction environment and crystal growth system for the coordination between silver ions and GSH compared to conventional methods using strong reducing agents. The AgNCs with intense red fluorescence (R-AgNCs@GSH, size ∼2.24 nm) and green fluorescence (G-AgNCs@GSH, size ∼1.93 nm) were produced by varying the ratios of silver sources and ligands, and could maintain stable fluorescence intensity over 6 months. Moreover, the CCK-8 study demonstrated that the R-AgNCs@GSH and G-AgNCs@GSH reduced by DANFC of excellent cytocompatibility (cell viability >90 %) and enable precise multicolor intracellular imaging of Hela cells in 1 h. This work proposes a novel method to synthesize water-soluble AgNCs with tunable fluorescence emission at room temperature based on the classical silver- mirror reaction (SMR) using DANFC as reducing agent, and the synthesized fluorescent AgNCs have great potential as novel luminescent nanomaterials in biological research., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The unique molecular structure of cellulose makes it challenging to dissolve at room temperature (R.T.), and the dissolution mechanism remains unclear. In this study, we employed ZnCl 2 aqueous solution for cellulose dissolution at R.T., proposing a novel four-stage dissolution mechanism. The efficient dissolution of cellulose in ZnCl 2 aqueous solution at R.T. involves four indispensable stages: rapid migration of hydrated Zn 2+ ions towards cellulose, sufficient penetration between cellulose sheets, strong interaction with cellulose hydroxyl groups, and effective dispersion of separated cellulose chains. The proposed four-stage dissolution mechanism was validated through theoretical calculations and experimental evidence. The hydrated Zn 2+ ions in ZnCl 2  + 3.5H 2 O solvent exhibited ideal migration, penetration, interaction, and dispersion abilities, resulting in efficient cellulose dissolution at R.T. Moreover, only slight degradation of cellulose occurred in ZnCl 2  + 3.5H 2 O at R.T. Consequently, the regenerated cellulose materials obtained from ZnCl 2  + 3.5H 2 O (R.T.) exhibited better mechanical properties. Notably, the solvent recovery rate reached about 95 % based on previous usage during five cycles. The solvent is outstanding for its green, low-cost, efficiency, simplicity, R.T. conditions and recyclability. This work contributes to a better understanding of the cellulose dissolution mechanisms within inorganic salt solvents at R.T., thereby guiding future development efforts towards greener and more efficient cellulosic solvents., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)