Graphene oxide quantum dots (GOQDs) are usually prepared using expensive carbon precursors such as carbon nanotubes (CNT) or graphene under the strong acidic condition, which requires an additional purifying process. Here, we first develop a facile pulsed laser ablation in liquid (PLAL) technique for preparing GOQDs using earth-abundant and low-cost coal as a precursor. Only ethanol and coal are used to produce GOQDs with excellent optical properties. The prepared GOQDs exhibit excellent optoelectronic properties which can be successfully utilized in bioimaging applications.

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Highly effective antifouling was achieved by immobilizing and stabilizing an acylase, disrupting bacterial cell-to-cell communication, in the form of cross-linked enzymes in magnetically separable mesoporous silica. This so-called "quorum-quenching" acylase (AC) was adsorbed into spherical mesoporous silica (S-MPS) with magnetic nanoparticles (Mag-S-MPS), and further cross-linked for the preparation of nanoscale enzyme reactors of AC in Mag-S-MPS (NER-AC/Mag-S-MPS). NER-AC effectively stabilized the AC activity under rigorous shaking at 200 rpm for 1 month, while free and adsorbed AC lost more than 90% of their initial activities in the same condition within 1 and 10 days, respectively. When applied to the membrane filtration for advanced water treatment, NER-AC efficiently alleviated the biofilm maturation of Pseudomonas aeruginosa PAO1 on the membrane surface, thereby enhancing the filtration performance by preventing membrane fouling. Highly stable and magnetically separable NER-AC, as an effective and sustainable antifouling material, has a great potential to be used in the membrane filtration for water reclamation.

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Subtilisin Carlsberg (SC) was immobilized and stabilized on magnetically-separable mesoporous silica (Mag-MSU-F) in the form of nanoscale enzyme reactors (NERs) based on the ship-in-a-bottle mechanism. Stabilized NERs of SC (NER-SC) were freeze-dried and successfully used for the transesterification of N-acetyl-L-phenylalanine ethyl ester with n-propanol in isooctane. Magnetic separation of Mag-MSU-F facilitated the repeated usages of stable NER-SC. This is the first demonstration for the use of stable and magnetically-separable NERs in an organic solvent, which has the potential for environmentally-friendly synthesis using enzymes in organic solvents.Enzymes are environmentally-friendly biocatalysts that can be used for chemical transformation processes including the production of biochemicals, bioalcohols and biodiesels. [1][2][3][4][5] Enzymes offer chemo-, regio-and stereo-selectivities under mild reaction conditions, such as ambient temperature and pressure, and physiological pH. [6][7][8] In particular, the change of medium from water to organic solvents enables synthetic reactions such as esterification, transesterification, aminolysis and thiotransesterification that are suppressed in aqueous solution. 9 As a result, the organic solvent enzymology has provided numerous synthetic and processing advantages. 10 Despite these advantages, one of the potential problems is the structural denaturation of native enzymes in organic solvents, leading to the poor enzyme stability and lowered enzyme activity. 11 As a potential solution, the stabilization and immobilization of enzymes has been proposed for successful nonaqueous enzymology with enhanced activity by preserving its native conformation. 12,13 † Electronic supplementary information (ESI) available. See

Graphene quantum dots (GQDs) and graphene oxide quantum dots (GOQDs) can be selectively produced by wavelength-modulated pulsed laser ablation in liquid (PLAL) method, which can used in different applications such as optoelectronic and biomedical applications, respectively.

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