We propose and demonstrate dendrimer-based coatings for a sensitive biochip surface that enhance the high-performance sorption of small molecules (i.e., biomolecules with low molecular weights) and the sensitivity of a label-free, real-time photonic crystal surface mode (PC SM) biosensor. Biomolecule sorption is detected by measuring changes in the parameters of optical modes on the surface of a photonic crystal (PC). We describe the step-by-step biochip fabrication process. Using oligonucleotides as small molecules and PC SM visualization in a microfluidic mode, we show that the PAMAM (poly-amidoamine)-modified chip's sorption efficiency is almost 14 times higher than that of the planar aminosilane layer and 5 times higher than the 3D epoxy-dextran matrix. The results obtained demonstrate a promising direction for further development of the dendrimer-based PC SM sensor method as an advanced label-free microfluidic tool for detecting biomolecule interactions. Current label-free methods for small biomolecule detection, such as surface plasmon resonance (SPR), have a detection limit down to pM. In this work, we achieved for a PC SM biosensor a Limit of Quantitation of up to 70 fM, which is comparable with the best label-using methods without their inherent disadvantages, such as changes in molecular activity caused by labeling.
The purpose of this study was to provide an immuno-mediated substantiation of the etiopathogenesis of mucositis and peri-implantitis based on the results of experimental, laboratory and clinical studies. The biopsy material was studied to identify impregnated nanoscale and microscale particles in the structure of pathological tissues by using X-ray microtomography and X-ray fluorescence analyses. Electron microscopy with energy-dispersive analysis identified the composition of supernatants containing nanoscale metal particles obtained from the surfaces of dental implants. The parameters of the nanoscale particles were determined by dynamic light scattering. Flow cytometry was used to study the effect of nanoscale particles on the ability to induce the activation and apoptosis of immunocompetent cells depending on the particles' concentrations during cultivation with the monocytic cell line THP-1 with the addition of inductors. An analysis of the laboratory results suggested the presence of dose-dependent activation, as well as early and late apoptosis of the immunocompetent cells. Activation and early and late apoptosis of a monocytic cell line when THP-1 was co-cultured with nanoscale metal particles in supernatants were shown for the first time. When human venous blood plasma was added, both activation and early and late apoptosis had a dose-dependent effect and differed from those of the control groups.