Search

Cellulose nanocrystals (CNCs) are featured with low toxicity, non‐trivial biocompatibility, and cell membrane penetration capability, which allow the constructions of nanoplatforms for biosensing and in vivo imaging. Interfacing CNCs and fluorescent materials into sensors/probes is thus highly topical and has received tremendous interest. This review covers the development of CNC extraction methods and, in particular, their impacts on the surficial properties of CNCs. Whereafter, recently reported strategies for fluorescent functionalizations of CNCs are summarized based on chemical modification, physical adsorption, or in situ growth. Choosing the most suitable strategy, according to the properties of both CNCs and fluorophores, for constructing fluorescent CNCs is also emphasized. With regard to applications of the fluorescent CNCs, this work focuses on the studies which have involved but not been limited to metal ion sensing, physiological pH detection, cell imaging, and tumor antiproliferation. Being aware of the highly flexible construction, appealing structural/optical properties, and outstanding performances in analysis/imaging, it is believed that CNCs are bound to be increasingly investigated in the future and widely applied in the biomedical area. [ABSTRACT FROM AUTHOR]

Abstract Cellulose nanocrystals (CNCs) are featured with low toxicity, non‐trivial biocompatibility, and cell membrane penetration capability, which allow the constructions of nanoplatforms for biosensing and in vivo imaging. Interfacing CNCs and fluorescent materials into sensors/probes is thus highly topical and has received tremendous interest. This review covers the development of CNC extraction methods and, in particular, their impacts on the surficial properties of CNCs. Whereafter, recently reported strategies for fluorescent functionalizations of CNCs are summarized based on chemical modification, physical adsorption, or in situ growth. Choosing the most suitable strategy, according to the properties of both CNCs and fluorophores, for constructing fluorescent CNCs is also emphasized. With regard to applications of the fluorescent CNCs, this work focuses on the studies which have involved but not been limited to metal ion sensing, physiological pH detection, cell imaging, and tumor antiproliferation. Being aware of the highly flexible construction, appealing structural/optical properties, and outstanding performances in analysis/imaging, it is believed that CNCs are bound to be increasingly investigated in the future and widely applied in the biomedical area.

Interfacing cellulose nanocrystals (CNCs) with fluorescent materials provides more possibilities for constructing of sensory/imaging platforms in biomedical applications. In this work, by harnessing the efficient extraction accompanied modification of CNCs and adjustable optical properties of carbon dots (CDs), we report the constructions and emission wavelength tuning of fluorescent CNCs (F-CNCs) composed of CNC nano-scaffolds and CDs. The as-prepared CNCs are densely decorated with citric acid (CA), which plays the role of carbon source for the in-situ synthesis of CDs on CNCs. For the F-CNCs carrying blue, green, and red emissive CDs, ethylenediamine (EDA), urea, and thiourea are the N or N/S sources. Fingerprints of chemical groups, morphological characters, and redox activities are resolved to elaborate the optical mechanisms of CDs with varying emission colors. The emission wavelength is adjusted by either changing the particle size or introducing new emission centers. Both are primarily achieved via precursor engineering. The F-CNCs reveal quantum yields (QY s) >22 % and negligible fluorescence quenching (< 6 %) upon continuous excitation as long as 24 h. Benefited from their cell membrane penetration capability, the F-CNCs with different emission wavelengths were challenged for multiplexed cytoplasm imaging. [Display omitted] • Fluorescent CNCs prepared by in-situ synthesis of carbon dots. • Emission wavelength of fluorescent CNCs are tailored by precursors. • Mechanisms of bandgap emission and trap state emission are elaborated. • Multiplexed cytoplasm imaging is achieved by use of the fluorescent CNCs. [ABSTRACT FROM AUTHOR]

Intelligent hydrogel has great application potentials in flexible sensing and artificial intelligence devices due to its intrinsic characteristics. However, developing an intelligent hydrogel with favorable properties including high strength, superior toughness, excellent conductivity and ionic sensing via a facile route is still a challenge. Herein, inspired by biologically chelating interactions of phytic acid (PA) in plants, a plant-inspired versatile intelligent nanocomposite hydrogel was readily fabricated by incorporating PA into the interface of fluorescent cellulose nanocrystals (F-CNC). Under PA "molecular bridge", the hydrogel simultaneously realized superflexibility (1000 %), high strength, superb self-healing ability, remarkable fluorescence and chloride ion sensibility as well as good ionic conductivity (2.4 S/m). The hydrogel could be assembled as a flexible sensor for real-time monitoring of human motion with excellent sensitivity and stability since high sensitivity toward both strain and pressure. F-CNC acted as a functional trigger could confer the hydrogel good fluorescence and high sensitivity toward chloride ion. This design confirms the synergy of F-CNC in boosting strength, ionic sensing, and ionic conductivity, addressing a long-standing dilemma among strength, stretchability, and sensitivity for intelligent hydrogel. The one-step incorporating tactic under mild ambient conditions may open an innovative avenue for the construction of intelligent hydrogel with novel properties. [Display omitted] • Conductive, self-healing, chlorion-sensitive, fluorescent hydrogel was designed. • Hydrogel-based sensor can monitor real-time human motion sensitively and stably. • PA triggered dynamic hydrogen bonded ionic conductive network inner the hydrogel. • F-CNC boosted the strength, ionic conductivity and chlorion sensing of hydrogel. [ABSTRACT FROM AUTHOR]