Alcohol-based reagents provide a versatile platform to covalently functionalize the surfaces of silica coated iron oxide nanoparticles through a silanol–alcohol condensation.

The surface functionalization of nanoparticles (NPs) is of great interest for improving the use of NPs in, for example, therapeutic and diagnostic applications. The conjugation of specific molecules with NPs through the formation of covalent linkages is often sought to provide a high degree of colloidal stability and biocompatibility, as well as to provide functional groups for further surface modification. NPs of lithium niobate (LiNbO3) have been explored for use in second–harmonic-generation (SHG)-based bioimaging, expanding the applications of SHG-based microscopy techniques. The efficient use of SHG-active LiNbO3 NPs as probes will, however, require the functionalization of their surfaces with molecular reagents such as polyethylene glycol and fluorescent molecules to enhance their colloidal and chemical stability and to enable a correlative imaging platform. Herein, we demonstrate the surface functionalization of LiNbO3 NPs through the covalent attachment of alcohol-based reagents through a silanol–alcohol condensation reaction. Alcohol-based reagents are widely available and can have a range of terminal functional groups such as carboxylic acids, amines, and aldehydes. Attaching these molecules to NPs through the silanol–alcohol condensation reaction could diversify the reagents available to modify NPs, but this reaction pathway must first be established as a viable route to modifying NPs. This study focuses on the attachment of a linear alcohol functionalized with carboxylic acid and its use as a reactive group to further tune the surface chemistry of LiNbO3 NPs. These carboxylic acid groups were reacted to covalently attach other molecules to the NPs using copper-free click chemistry. This derivatization of the NPs provided a means to covalently attach polyethylene glycols and fluorescent probes to the NPs, reducing NP aggregation and enabling multimodal tracking of SHG nanoprobes, respectively. This extension of the silanol–alcohol condensation reaction to functionalize the surfaces of LiNbO3 NPs can be extended to other types of nanoprobes for use in bioimaging, biosensing, and photodynamic therapies.

Vitamin D is an essential nutrient with important immunomodulatory properties. As a fat-soluble compound, Vitamin D (and its D3 form) is immiscible with water, which presents challenges to absorption. In an in vitro setting, the current study characterizes novel micellar formulations of Vitamin D3 designed to improve absorption. Techniques used to evaluate and compare the micellar formulations against a non-micellar formula include the following: cryo-SEM to determine morphology; laser diffraction to determine particle size and distribution; zeta potential to determine stability of the particles; solubility assays to determine solubility in water and gastrointestinal media; and Caco-2 cell monolayers to determine intestinal permeability. Results show advantageous features (particle size range in the low micrometres with an average zeta potential of −51.56 ± 2.76 mV), as well as significant improvements in intestinal permeability, in one optimized micellar formula (LipoMicel®). When introduced to Caco-2 cells, LipoMicel’s permeability was significantly better than the control (p < 0.01; ANOVA). Findings of this study suggest that the novel micellar form of Vitamin D3 (LipoMicel) has the potential to promote absorption of Vitamin D3. Thus, it can serve as a promising candidate for follow-up in vivo studies in humans.

BPA-based benzoxazine monomer (BA-a) solubilized in end-group ditosylated poly(ether sulfone) [α,ω-PSU(OTs) 2 ] undergoes an accelerated grafting ring-opening polymerization (ROP) to afford unique graft copolymer hybrids with predictable thermal properties and improved uniformity and superior mechanical properties. The α,ω-PSU(OTs) 2 was synthesized from the parent α,ω-dihydroxy poly(ether sulfone) with the conversion of end-groups quantified by 1 H NMR and GPC. The two polymers were used to create two blend series with a BPA-based benzoxazine monomer (BA-a) and heated to the polybenzoxazine-based products. The grafting ROP reaction of tosylated poly(ether sulfone) with the resulting polybenzoxazine network was studied by using DSC, FT-IR, SEM, and UV−vis and indicated that tosylated end-groups accelerate BA-a polymerization and afford products that are composed of P(BA-a)-graft-PSU with excess but well-mixed PSU. The approach allows for the fabrication of free-standing films that had higher tensile modulus, greater resiliency, and less mechanical property variation compared to their α,ω-dihydroxy poly(ether sulfone) analogues. The properties of the tosylated poly(ether sulfone) blend films and the accelerated cure of included benzoxazine allowed for the preparation of thin films on millimeter-scaled metal rods where the mechanically robust films do not undergo significant melt flow when cured by inductive heating.