Correction: Boronate affinity-based photoactivatable magnetic nanoparticles for the oriented and irreversible conjugation of Fc-fused lectins and antibodies.

[This corrects the article DOI: 10.1039/C9SC01613A.].

Investigating a Boronate-Affinity-Guided Acylation Reaction for Labelling Native Antibodies.

The excellent molecular recognition capabilities of monoclonal antibodies (mAbs) have opened up exciting opportunities for biotherapeutic discovery. Taking advantage of the full potential of this tool necessitates affinity ligands capable of conjugating directly with small molecules to a defined degree of biorthogonality, especially when modifying natural Abs. Herein, a bioorthogonal boronate-affinity-based Ab ligand featuring a 4-(dimethylamino)pyridine and an S-aryl thioester to label full-length Abs is reported. The photoactivatable linker in the acyl donor facilitated purification of azide-labelled Ab (N3 -Ab) was quantitatively cleaved upon brief exposure to UV light while retaining the original Ab activity. Click reactions enabled the precise addition of biotin, a fluorophore, and a pharmacological agent to the purified N3 -Abs. The resulting immunoconjugate showed selectivity against targeted cells. Bioorthogonal traceless design and reagentless purification allow this strategy to be a powerful tool to engineer native antibodies amenable to therapeutic intervention.

Sugar nucleotide regeneration system for the synthesis of Bi- and triantennary N-glycans and exploring their activities against siglecs.

Enzymatic synthesis that is commenced by the sugar nucleotide regeneration system (SNRS) protocol can minimize 1) the consumption of exorbitant sugar nucleotides, 2) the amount of transferases required, and 3) byproduct feedback inhibition. In this study, LacNAc extensions/modifications of the N-linked mannose core were carried out efficiently with SNRS with high yields and purities on all branches in a uniform manner. In addition, we demonstrate that with SNRS, bacterial glycosyltransferases exhibit a wide acceptor tolerance for bi- and triantennary mannose core structures as substrates for target oligosaccharides. The synthesized small library of mannose core-based glycans and linear O-glycans were screened for their binding affinity against h-Siglecs 2, 4, 7, 9, 14, 15, and m-Siglec-15 to explore their structure-based binding preferences. Microarray data revealed that each Siglec showed few distinct yet overlapping specificities. An increase in branching from mono to di or tri antennary did not necessarily lead to increasing affinity. Glycans with the disialoside sequence α(2,3)α(2,8)/α(2,6)α(2,8) showed high specificity and affinity for Siglec-7, and sLex α(2,3) exhibited a strong affinity for Siglec-9. Explicit recognition of α(2,6)α(2,3)- linear and α(2,3)α(2,6)-branched glycans by Siglecs-2, 4, and 15, respectively, suggests that these structures can act as potential candidates for the further development of high-affinity ligands.

Proton-ELISA: Electrochemical immunoassay on a dual-gated ISFET array.

Here we report an electrochemical immunoassay platform called Proton-ELISA (H-ELISA) for the detection of bioanalytes. H-ELISA uniquely utilizes protons as an immunoassay detection medium, generated by the enzyme glucose oxidase (GOx) coupled with Fenton's reagent in a proton amplification reaction cascade that results in a highly amplified signal. A proton-sensitive dual-gated ion-sensitive field effect transistor (DG-ISFET) sensor was also developed for sensitive and accurate detection of the proton signal in H-ELISA. The DG-ISFET sensor comprises of a 128 × 128 array of 16,384 sensing transistors each with an individually addressable back gate to allow for a very high signal throughput and improved accuracy. We then demonstrated that the platform could detect C-reactive protein and immunoglobulin E down to concentrations of 12.5 and 125 pg/mL, respectively. We further showed that the platform is compatible with complex biological sample conditions such as human serum, suggesting that the platform is sufficiently robust for potential diagnostic applications.