Biodegradable periodic mesoporous organosilica (BPMO) has recently emerged as a promising type of mesoporous silica-based nanoparticle for biomedical applications. Like mesoporous silica nanoparticles (MSN), BPMO possesses a large surface area where various compounds can be attached. In this work, we attached boronophenylalanine (10BPA) to the surface and explored the potential of this nanomaterial for delivering boron-10 for use in boron neutron capture therapy (BNCT). This cancer therapy is based on the principle that the exposure of boron-10 to thermal neutron results in the release of a-particles that kill cancer cells. To attach 10BPA, the surface of BPMO was modified with diol groups which facilitated the efficient binding of 10BPA, yielding 10BPA-loaded BPMO (10BPA-BPMO). Surface modification with phosphonate was also carried out to increase the dispersibility of the nanoparticles. To investigate this nanomaterial’s potential for BNCT, we first used human cancer cells and found that 10BPA-BPMO nanoparticles were efficiently taken up into the cancer cells and were localized in perinuclear regions. We then used a chicken egg tumor model, a versatile and convenient tumor model used to characterize nanomaterials. After observing significant tumor accumulation, 10BPA-BPMO injected chicken eggs were evaluated by irradiating with neutron beams. Dramatic inhibition of the tumor growth was observed. These results suggest the potential of 10BPA-BPMO as a novel boron agent for BNCT.

Herein we report the synthesis of a new family of styryl-functionalized polyhedral oligomeric silsesquioxanes (Tn, where n = 8, 10 and 12), in which the organic moiety is linked to all n vertices of the Tn cages via the phenyl ring rather than the vinyl group. In contrast to earlier studies in which the styryl group is linked to the cage via the vinyl moiety, our approach ensures that the vinyl moiety is less sterically hindered and available for post-functionalization. The functional Tn cages have been characterized by a range of techniques, including single crystal X-ray diffraction, multinuclear solution NMR ( 1 H, 13 C and 29 Si), MALDI-MS and FTIR. The solid-state structure of the T8 compound exhibited two non-equivalent Si8O12 cage atoms, which has not been previously reported in the functionalized T8 system, although all cage atoms in the corresponding T10 and T12 systems were equivalent. In contrast, multinuclear solution NMR data indicated that all cages in the T8 system were equivalent in solution, suggesting that the non-equivalent cage geometries arise in the solid state to optimize the packing of the functionalized cages.

The first observation of fluxional covalent Si⋯F interactions in functionalised T8-F cage silsesquioxanes containing an encapsulated fluoride is reported.