Carbon dot-based fluorescent antibody nanoprobes as brain tumour glioblastoma diagnostics.

The development of efficient and sensitive tools for the detection of brain cancer in patients is of the utmost importance particularly because many of these tumours go undiagnosed until the disease has advanced and when treatment is less effective. Current strategies employ antibodies (Abs) to detect Glial Fibrillary Acid Protein (GFAP) in tissue samples, since GFAP is unique to the brain and not present in normal peripheral blood, and it relies on fluorescent reporters. Herein we describe a low cost, practical and general method for the labelling of proteins and antibodies with fluorescent carbon dots (CD) to generate diagnostic probes that are robust, photostable and applicable to the clinical setting. The two-step protocol relies on the conjugation of a dibenzocyclooctyne (DBCO)-functionalised CD with azide functionalised proteins by combining amide conjugation and strain promoted alkyne-azide cycloaddition (SPAAC) ligation chemistry. The new class of Ab-CD conjugates developed using this strategy was successfully used for the immunohistochemical staining of human brain tissues of patients with glioblastoma (GBM) validating the approach. Overall, these novel fluorescent probes offer a promising and versatile strategy in terms of costs, photostability and applicability which can be extended to other Abs and protein systems.

Chemo-enzymatic synthesis of imidazolium-tagged sialyllactosamine probes.

Two novel α-linked sialyltrisaccharide imidazolium-type probes (ITags) based on the structures of biologically relevant 6'-sialyllactosamine and 3'-sialyllactosamine were efficiently and stereoselectively prepared using a chemo-enzymatic approach. The apparent kinetic parameters for the enzyme catalyzed transformations with α-2,3-sialyltransferase (α-2,3-ST) and α-2,6-sialyltransferase (α-2,6-ST) were measured by LC-MS using the ionic probes. This strategy demonstrates the suitability of the ITags to probe glycosyltransferase activity and their versatility in the preparation of sialylated epitopes for glycobiology research.

Combinatorial ionic catch-and-release oligosaccharide synthesis (combi-ICROS).

A combinatorial ionic-liquid-supported "catch-and-release" strategy for oligosaccharide synthesis (combi-ICROS) is reported. A series of ß-(1→6) glucan di-, tri- and tetra-saccharides were synthesized in one pot to showcase the versatility of the strategy.