Micron- and submicron-scale 3D structure realization nowadays is possible due to the two-photon photopolymerization (TPP) direct laser writing photolithography (DLW photolithography) method. However, the achievement of lithographic features with dimensions less than 100 nm is in demand for the fabrication of micro-optical elements with high curvature values, including X-ray microlenses. Spectroscopic and photochemical study of a photoinitiator (PI) based on a methyl methacrylate derivative of 2,5-bis(4-(dimethylamino)benzylidene) cyclopentanone was performed. Enhanced intersystem crossing in the methyl methacrylate derivative results in increased radical generation for the subsequent initiation of polymerization. A comprehensive study of the new photocompositions was performed, with particular emphasis on photochemical constants, the degree of photopolymerization, and topology. The optimal parameters for the fabrication of mechanically stable structures were determined in this research. The threshold dose parameters for lithography (radiation power of 5 mW at a speed of 180 µm/s) when trying to reach saturation values with a conversion degree of (35 ± 1) % were defined, as well as parameters for sub-100 nm feature fabrication. Moreover, the 45 nm feature size for elements was reached. Fabrication of X-ray lens microstructures was also demonstrated.

A wide range of water-soluble quaternary ammonium acylhydrazones based on catecholaldehyde were synthesized and characterized using NMR, IR spectroscopy, and elemental analysis. The total antioxidant capacity of the acylhydrazones discussed herein was estimated via coulometric titration with electrogenerated bromine. Pyridinium derivatives 11a–e exhibited the highest antioxidant capacity. Quaternary ammonium acylhydrazones demonstrated high antimicrobial activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus strains. Furthermore, low hemo- and cytotoxicity and the absence of a negative effect on the hemostatic system were confirmed for the studied compounds. According to the results of a CV test, the antimicrobial effect of the most active acylhydrazones, namely, 9a, 10b, 10c, and 11a, is associated with the destruction of the bacterial cell wall. High or moderate activity against phytopathogens of bacterial origin was observed for all the acylhydrazones evaluated. Anti-aggregation activity was observed for compound 10b; the extent was 1.6-fold greater than that exhibited by acetylsalicylic acid. On the contrary, compound 9d exhibited a pro-aggregant effect (with a 6.3% increase in platelet aggregation and a >15% decrease in the latent period compared to the control). Thus, the data obtained can be considered the basis for further pharmaceutical development of these effective drugs with antithrombotic and hemostatic potential.

Free-radical photopolymerization has been widely used in additive technologies, in particular, stereolithography using single- and two-photon initiated polymerization. The single-photon stereolithography affords the objects with about 100 μm resolution. The two-photon stereolithography initiated with a femtosecond near-infrared laser can afford arbitrary 3D microstructures with ultrahigh resolution at micro- and nanoscale level (~100 nm). Herein each of the mentioned method and the mechanisms of single- and two-photon excitation are reviewed. The recent results on the components of the photopolymerizable resin as well as the approaches to decrease the size of the elements of objects and accelerate their formation have been generalizated and systematized.

Two new photoinitiators of the α,α-bis(arylidene)cyclopentanone series having an unsymmetrical structure and containing two methacrylate units have been synthesized. The electrochemical and photoluminescent properties of the initiators have been studied. In the presence of the initiators, photopolymerization of pentaerythritol triacrylate was carried using radiation at λ = 365/405 nm (one-photon process) and focused femtosecond laser radiation with a wavelength of 780 nm (two-photon process). For each initiator, “fabrication windows” were determined and 3D microstructures of complex architecture were fabricated by DLW nanolithography.

New initiator monomers, derivatives of 3,5-di-tert-butyl-o-benzoquinone containing the 2‑hydroxyethyl methacrylate (HEMA) and pentaerythritol triacrylate (PETA) moieties, have been synthesized. The activity of new o-quinones has been examined in the visible light-induced polymerization (coinitiator N,N-dimethylcyclohexylamine) of oligocarbonate dimethacrylate OCM‑2. The thermal stability of the obtained polymers has been studied. Polymers have been prepared by copolymerization of the synthesized o-quinones with HEMA and PETA (initiator azobisisobutyronitrile, 80°C), and the migration of o-quinones from the products has been evaluated.

Free-radical photopolymerization has been widely used in additive technologies, in particular, stereolithography using single- and two-photon initiated polymerization. The single-photon stereolithography affords the objects with about 100 μm resolution. The two-photon stereolithography initiated with a femtosecond near-infrared laser can afford arbitrary 3D microstructures with ultrahigh resolution at micro- and nanoscale level (~100 nm). Herein each of the mentioned method and the mechanisms of single- and two-photon excitation are reviewed. The recent results on the components of the photopolymerizable resin as well as the approaches to decrease the size of the elements of objects and accelerate their formation have been generalizated and systematized.