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To achieve a rapid and facile quantitative evaluation of Sudan I illegally added in ketchup, fluorescent carbon quantum dots with excellent stability in acidic environments are required as the actual pH value of ketchup is close to 4.0. In this paper, we developed a green approach to prepare sulfur-doped carbon quantum dots (SCQDs) via hydrothermal treatment of lignin, isolated from pre-hydrolysis liquor, in sulfuric acid solution. The resultant SCQDs from lignin possessed sulfur-containing groups, which exhibited excellent fluorescence with a quantum yield up to 13.5% and good stability in acidic environments with a wide pH range of 0-5.0. Therefore, the SCQDs were successfully employed as a sensor to detect Sudan I in acidic solutions with excellent selectivity and sensitivity. The linear range for Sudan I was 0-40 μM, while the limit of detection was 0.12 μM. In addition, the fluorescent indicator paper functionalized with SCQDs also showed outstanding selectivity to Sudan I. The proposed SCQD sensing system not only displayed application potential for quantitative evaluation of Sudan I dye in practical samples, but also provided a way to convert lignin-based waste into highly valued nanoscale materials.

Natural dispersants and flocculants, often referred to as dispersion stabilizers and liquid-solid separators, respectively, have secured a promising role in the bioprocessing community. They have various applications, including in biomedicine and in environmental remediation. A large fraction of existing dispersants and flocculants are synthesized from non-safe chemical compounds such as polyacrylamide and surfactants. Despite numerous advantages of synthetic dispersants and flocculants, issues such as renewability, sustainability, biocompatibility, and cost efficiency have shifted attention towards natural homologues, in particular, cellulose-based ones. Within the past decade, cellulose derivatives, obtained via chemical and mechanical treatments of cellulose fibrils, have successfully been used for these purposes. In this review article, by dividing the functional cellulosic compounds into "polymeric" and "nanoscale" categories, we provide insight into the engineering pathways, the structural frameworks, and surface chemistry of these "green" types of dispersants and flocculants. A summary of their efficiency and the controlling parameters is also accompanied by recent advances in their applications in each section. We are confident that the emergence of cellulose-based dispersing and flocculating agents will extend the boundaries of sustainable green technology.

A paper-based platform was developed and tested for studies on basic cell culture, material biocompatibility, and activity of pharmaceuticals in order to provide a reliable, robust and low-cost cell study platform. It is based upon a paper or paperboard support, with a nanostructured latex coating to provide an enhanced cell growth and sufficient barrier properties. Wetting is limited to regions of interest using a flexographically printed hydrophobic polydimethylsiloxane layer with circular non-print areas. The nanostructured coating can be substituted for another coating of interest, or the regions of interest functionalized with a material to be studied. The platform is fully up-scalable, being produced with roll-to-roll rod coating, flexographic and inkjet printing methods. Results show that the platform efficiency is comparable to multi-well plates in colorimetric assays in three separate studies: a cell culture study, a biocompatibility study, and a drug screening study. The color intensity is quantified by using a common office scanner or an imaging device and the data is analyzed by a custom computer software without the need for expensive screening or analysis equipment.

Sulfur dioxide (SO 2 ) in biological systems is an important gaseous signal molecule and plays important roles in physiological activities. It can be endogenously produced by enzymes in mitochondria during oxidation of sulphur-containing molecules. Thus, the development of probes for sulfur dioxide detection in biological environment is necessary. Here, a new near-infrared fluorescent probe (Rh-TPA) with multiple fluorescence emission was constructed and applied for SO 2 derivative detection. Rh-TPA was constructed via conjugation of a rhodamine analogue with a triphenylamine group. Rh-TPA exhibited a major emission peak at 740 nm and a shoulder peak at 810 nm. After interacting with SO 2 derivatives, the conjugated system dissociated into two smaller chromophores with two emission peaks (520 nm and 570 nm) in the visible region. The probe showed negligible cytotoxicity, as demonstrated by the MTT results. Biological imaging application experiments indicated that the probe can be used to image SO 2 derivatives in HeLa cells and living zebrafish.

Many animals such as snails and Chinese giant salamanders can secrete mucus for moisturizing, eliminating swelling and inflammation, and promoting wound healing; this implies that high viscous bio-functional materials inspired by mucus may show potential for biomedical applications. Herein, we developed a maltose-like injectable nanocomposite via the combination of chitosan polysaccharide and clay rectorite for hemostasis. Through the hemostatic property of rectorite, the viscous nanocomposite decreased the in vitro clotting time by 43%. Moreover, an in vitro porcine skin model confirmed that the viscous nanocomposite can stably adhere on skin and impede blood bleeding successfully. Importantly, the internal structure of the nanocomposites, chitosan intercalating into rectorite interlayers, provided a physical cross-linked network to decrease the release of rectorite from the nanocomposite and its invasion into the blood. Therefore, this viscous injectable nanocomposite provided a concept for a facile and sustainable biomaterial for skin hemostasis.

This study reported the direct utilization of bagasse as an ultra-light aerogel with AgNPs for the first time. Firstly, AgNPs were synthesized in situ using a green route with bagasse, a by-product of the refined sugar industry. During the reaction, the crystalline region of cellulose in bagasse was destroyed, and some groups of bagasse were partly oxidized into C[double bond, length as m-dash]O of ketone, which confirms the reducing capacity of bagasse. Then, the obtained bagasse-AgNP composite was dissolved in EmimAc to prepare an aerogel with AgNPs. The aerogel piled up in slices, and its weight after swelling in water was about 19 times the dry weight, and the aerogel did not crush a flower branch because its density was only 0.035 g cm -3 , although the mole and mass ratios of the Ag atom were 5.26% and 29.94% in the aerogel, respectively. Furthermore, the obtained aerogel showed a strong antibacterial effect, especially against E. coli and P. aeruginosa. This study not only provides an interesting way for bagasse to be applied directly, but also develops an antibacterial biomass-based ultra-light aerogel without AgNP dissociation.

Nanostructures encapsulating multiple quantum dots (QDs) are of special interests for live cell imaging and biomolecular recognition due to their inherent signal amplification. In this study, a novel type of biomass-based nanomicelles was prepared and characterized for facile loading and solubilization of fluorescent hydrophobic CdSe/ZnS QDs in water. The biobased nanomicelles were formed by the self-assembly of amphiphilic cellulose-graft-poly (p-dioxanone) (MCC-g-PPDO) synthesized via homogeneous ring-opening polymerization in an ionic liquid. Through a simple physical loading method, multiple lipophilic CdSe/ZnS QDs can be simultaneously encapsulated in one MCC-g-PPDO micelle showing an obviously enlarged micelle size, whereas the loaded QDs exhibited a negligible change in their size and size distribution. The QDs-loaded cellulosic micelles exhibited good optical stability, narrow emission bandwidth as well as an acceptable quantum yield of ∼27%. Successful tumor cell internalization and negligible cytotoxicity were observed with these light-emitting cellulosic micelles. It was found that over 90% of the cells were viable after 24 h of exposure and the fluorescent signal inside the cells reached a maximum after 2 h of exposure. These QDs-loaded cellulosic nanomicelles derived from biomass are a promising candidate for bioimaging or other functional applications.

A series of novel water-soluble amphiphilic copolymers containing ciprofloxacin (CPF) and quaternary ammonium salts were prepared by the free-radical copolymerization of methacrylate monomers with CPF, quaternary ammonium salt (QAS) monomers and butyl acrylate (BA). The copolymers were characterized by 1 H-NMR, charge density and UV measurements. The antimicrobial activities of the copolymers, based on the minimum inhibition concentration (MIC) against Escherichia coli (E. coli), varied with hydrophobic BA content in the copolymers. The incorporation of the antimicrobial moiety ciprofloxacin further enhanced the antibacterial activities of the copolymers, reducing the MIC to 4.0 ppm. The UV 260 absorption measurements were applied to reveal the dynamic antimicrobial process of the copolymers. The results of inhibition zones and shaking flask methods of antimicrobial-modified fibers showed that the copolymers had excellent antimicrobial activities when applied to cellulose fibers. In the presence of 2 wt% (based on oven-dried fibers) of the copolymer, the growth inhibition reached 100%.