The phenylboronic acid azoprobe (BA-Azo)/γ-cyclodextrin (γ-CD) complex exhibits a selective response for D-glucose by forming a supramolecular 2 : 1 inclusion complex of the azoprobes with D-glucose inside the γ-CD cavity.

There is an urgent need to develop a rapid and selective method for the detection of bacteria because delayed diagnosis and the overuse of antibiotics have triggered drug resistance in bacteria. To this end, we prepared boronic acid-modified poly(amidoamine) generation 4 (B-PAMAM(G4)) dendrimer as cross-linking molecules that form aggregates with bacteria. Within 5 min of adding B-PAMAM(G4) dendrimer solution to a bacterial suspension, large aggregates were observed. Interestingly, the aggregate formation with various bacteria was pH-dependent. In basic pH, both Gram-positive and Gram-negative bacteria formed aggregates, but in neutral pH, only Gram-positive bacteria formed aggregates. We revealed that this bacteria-selective aggregation involved the bacterial surface recognition of the phenylboronic acid moiety of B-PAMAM(G4) dendrimer. In addition, we demonstrated that the spherical structure of B-PAMAM(G4) was one of the important factors for the formation of large aggregates. The aggregation was also observed in the presence of ≤10 mM fructose. B-PAMAM(G4) dendrimer is expected to be a powerful tool for the rapid and selective discrimination between Gram-positive and Gram-negative bacteria.

Nanogels open up access to a wide range of applications and offer among others hopeful approaches for use in the field of biomedicine. This review provides a brief overview of current developments of nanogels in general, particularly in the fields of drug delivery, therapeutic applications, tissue engineering, and sensor systems. Specifically, cyclodextrin (CD)‐based nanogels are important because they have exceptional complexation properties and are highly biocompatible. Nanogels as a whole and CD‐based nanogels in particular can be customized in a wide range of sizes and equipped with a desired surface charge as well as containing additional molecules inside and outside, such as dyes, solubility‐mediating groups or even biological vector molecules for pharmaceutical targeting. Currently, biological investigations are mainly carried out in vitro, but more and more in vivo applications are gaining importance. Modern molecular imaging methods are increasingly being used for the latter. Due to an extremely high sensitivity and the possibility of obtaining quantitative data on pharmacokinetic and pharmacodynamic properties, nuclear methods such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) using radiolabeled compounds are particularly suitable here. The use of radiolabeled nanogels for imaging, but also for therapy, is being discussed.

The aqueous extract of the leaves of Odontonema strictum (OSM) is used in folk medicine for its antihypertensive properties, and it contains a wide range of secondary metabolites, mostly polyphenols such as verbascoside and isoverbascoside, which could play a major role in the preparation of silver nanoparticles. In this study, we aimed to prepare AgNPs for the first time using the OSM leaf extract (OSM-AgNPs) to investigate their free radical-scavenging potency against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide (H₂O₂). Dynamic light scattering (DLS), UV/Vis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS) were used to characterize the OSM-AgNPs. With a size around 100 nm and a ζ-potential of −41.1 mV, OSM-AgNPs showed a good stability and a better colloidal property due to electrostatic repulsion and the dispersity. The strong absorption peak at 3 keV in the EDX spectra indicated that silver was the major constituent. Additionally, the existence of silver atoms was confirmed by the Ag 3d_5/2 peak around 367 eV in the XPS spectra. IC₅₀ values of 116 μg/mL and 4.4 μg/mL were obtained for the scavenging activities of DPPH and H₂O₂, respectively. The synthetic OSM-AgNPs can be further exploited as potential antioxidant agents.