Carbon dots have been considered as a solution to the challenges that semiconductor quantum dots have encountered because they are more biocompatible and can be synthesized from abundant and nontoxic materials such as biomass. This review will highlight the advantages of these biomass-based carbon dots in terms of synthesis, properties, and applications in the biomedical field. Furthermore, future applications especially in the biomedical field of biomass-based carbon dots as well as the challenges of semiconductor quantum dots such as biocompatibility, photobleaching, environmental challenges, toxicity, and poor solubility will be discussed in detail. Biomass-derived quantum dots, a subsection of carbon dots that are the most desirable for future research, will be focused upon including from synthesis to applications. Finally, the future development of biomass derived quantum dots in the biomedical field will be discussed and evaluated to unlock the potential for their applications.

Biomass-Based Carbon Dots: Current Development and Future Perspectives.

Fluorescent semiconductor nanocrystals (quantum dots) have the potential to revolutionize biological imaging, but their use has been limited by difficulties in obtaining nanocrystals that are biocompatible. To address this problem, we encapsulated individual nanocrystals in phospholipid block–copolymer micelles and demonstrated both in vitro and in vivo imaging. When conjugated to DNA, the nanocrystal-micelles acted as in vitro fluorescent probes to hybridize to specific complementary sequences. Moreover, when injected into Xenopus embryos, the nanocrystal-micelles were stable, nontoxic (<5 × 109 nanocrystals per cell), cell autonomous, and slow to photobleach. Nanocrystal fluorescence could be followed to the tadpole stage, allowing lineage-tracing experiments in embryogenesis.

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In vivo imaging with quantum dots encapsulated in phospholipid micelles

The concept of active site in heterogeneous catalysis

Enzymes, as biocatalysts, speed up chemical reactions to reach equilibrium in living organisms. The abnormal enzyme activity is closely related to many diseases, and they are regarded as biomarkers in clinical medicine. Thus, determination of enzyme activity has considerable importance. Among the developed methods, quantum/carbon dots (QDs/CDs)-based fluorescent sensors provide alternative platforms to monitor enzyme activity. Both quantum dots (QDs) and carbon dots (CDs) as excellent fluorescent materials possess outstanding photostability, tunable emission spectra and better biocompatibility. Thus, they present incomparable advantages in sensing. This review summarizes the advances in fluorescent assays design, sensing mechanism and corresponding applications of QDs/CDs-based fluorescent sensors for enzyme activity detection. Finally, challenges and development trends of QDs/CDs as enzymatic sensors are also discussed. We believe that this review will provide an insight for the development of novel fluorescent sensors for detection of enzyme activity.

Quantum/carbon dots-based fluorescent assays for enzyme activity

Designing of nanomaterials has now become a top-priority research goal with a view to developing specific applications in the biomedical fields. In fact, the recent trends in the literature show that there is a lack of in-depth reviews that specifically highlight the current knowledge based on the design and production of nanomaterials. Considerations of size, shape, surface charge and microstructures are important factors in this regard as they affect the performance of nanoparticles (NPs). These parameters are also found to be dependent on their synthesis methods. The characterisation techniques that have been used for the investigation of these nanomaterials are relatively different in their concepts, sample preparation methods and obtained results. Consequently, this review article aims to carry out an in-depth discussion on the recent trends on nanomaterials for biomedical engineering, with a particular emphasis on the choices of the nanomaterials, preparation methods/instruments and characterisations techniques used for designing of nanomaterials. Key applications of these nanomaterials, such as tissue regeneration, medication delivery and wound healing, are also discussed briefly. Covering this knowledge gap will result in a better understanding of the role of nanomaterial design and subsequent larger-scale applications in terms of both its potential and difficulties.

Nanomaterials for Biomedical Applications: Production, Characterisations, Recent Trends and Difficulties.

Recent advances in non-toxic quantum dots and their biomedical applications

Butadiene is an important monomer for synthetic rubbers. Currently, the annual demand of ∼16 million tonnes is satisfied by butadiene produced as a byproduct of steam naphtha cracking where ethylene and propylene are the main products. The availability of large amounts of shale gas and condensates in the USA since about 2008 has led to a change in the cracker feed from naphtha to ethane and propane, affecting the amount of butadiene obtained. This has provided the impetus to look into direct processes for butadiene production. One option is the eco-friendly conversion of (bio) ethanol to butadiene (ETB). This process had been developed in the 1930s in the then Soviet Union. It was operated on a large scale in USA during World War II but has since been abandoned in favour of petroleum-based processes. The current trend, driven both by the availability of the raw material and ecological considerations, may make this process feasible again, particularly if the catalytic systems can be improved. This critical review discusses recent catalysts for the ETB process with special focus on the development since 2014, benchmarking them against earlier systems with a large database of operational experience.

Recent Advances in Catalysts for the Conversion of Ethanol to Butadiene

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Ismail Bin Samsudin

Papers

Recent advances in non-toxic quantum dots and their biomedical applications

Recent Advances in Catalysts for the Conversion of Ethanol to Butadiene

Zeolites in catalysis: sustainable synthesis and its impact on properties and applications

Mg-stabilized subnanometer Rh particles in zeolite Beta as highly efficient catalysts for selective hydrogenation

Polymer-Encapsulated Crystalline Zirconium Phosphates as Nh4+ and K+ Ion Exchangers for Application in Sorbent Dialysis Cartridges