Peptides and small molecules may play an important role in immuno-oncology because they may bind to multiple immune checkpoint proteins via rational design, opening opportunity for a new generation of novel PD-1/PD-L1 inhibitors.

Although nanomaterials have been widely investigated for drug delivery, imaging and immunotherapy, their potential roles in triggering innate cellular immune responses while simultaneously serving as imaging enhancer remain unexplored. In this work, gold nanoparticles (GNPs) conjugated to the tumor-targeting anti-GD2 antibody hu14.18K322A, namely HGNPs, were designed and synthesized to specifically enhance computerized tomography (CT) imaging contrast and to stimulate the attack of neuroblastoma and melanoma cells by natural killer (NK) cells. The HGNPs specifically targeted GD2-positive neuroblastoma (NB1691) and melanoma (M21) cells, with an enhancement of CT contrast images of the HGNP-labeled cell pellets by 5.27- and 7.66-fold, respectively, compared to images of unlabeled cell pellets. The HGNPs also triggered NK-mediated antibody-dependent cellular cytotoxicity (ADCC) in NB1691 and M21 cells with a two-fold higher efficacy compared to that elicited by hu14.18K322A alone, with no adverse effect to GD2-negative PC-3 cells. These results suggest that HGNPs are promising theranostic agents for neuroblastoma and melanoma cancers.

Blockade of PD-1/PD-L1 interactions using PD-1/PD-L1 pathway modulators has shown unprecedented clinical efficacy in various cancer models. Current PD-1/PD-L1 modulators approved by FDA are exclusively dominated by therapeutic antibodies. Nevertheless, therapeutic antibodies also exhibit several disadvantages such as low tumor penetration, difficulty in crossing physiological barriers, lacking oral bioavailability, high manufacturing costs, inaccessible to intracellular targets, immunogenicity, immune-related adverse events (irAEs). Modulation of PD-1/PD-L1 pathway using small molecules may be an alternative approach to mobilize immune system to fight against cancers. In this review, we focus on summarizing the recently disclosed chemical structures and preliminary structure-activity relationships (SARs) of small molecules as PD-1/PD-L1 modulators for cancer immunotherapy.

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Fluorescent whitening agents (also called optical dyes) contain a large conjugated system. They can absorb invisible ultraviolet (UV) light and convert it into blue or purple visible light with a longer wavelength. [1][2][3][4] Therefore, fluorescent whitening agents can compensate for unwanted yellow in the matrix and make products appear whiter and brighter. As functional optical materials, they enable treated substrates to appear brighter and more pleasing to the eye, significantly enhancing their commercial value, 5-8 therefore fluorescent whitening agents are widely used in papermaking, 9,10 polyester fabrics, 11 coatings and paints. They can also be used as photo-electron transfer sensors, 12,13 fluorescent imaging materials, 14 pressure reversible sensors, 15 UV absorbers, 16 surface modifiers, 17 electroluminescent materials, 18 fluorescence switchers 19 and pathogen detection reagents. 20 Stilbene fluorescent whitening agents represent the main body of fluorescent whitening agents, accounting