Red blood cell targeting to collagen-coated surfaces

AbstractThe interaction of human red blood cells carrying antihuman collagen antibody with collagen-coated surfaces was studied. Avidin was used as bifunctional crosslinking agent for the attachment of antibody to the red blood cell surface. Antibody-carrying red blood cells efficiently and specifically bound to collagen-coated surface covering a significant part of the surface. The components of normal blood had an insignificant effect on red blood cell binding. A model of drug targeting to the injured sites(s) of blood vessel wall is proposed

Collagen-based hydrogel functionalized with rhBMP-2

The study showed the cytocompatibility, matrix, and osteoinductive properties of collagen-fibronectin hydrogel impregnated with rhBMP-2. After 7 days of MSCs incubated with osteoplastic material the cell viability was 93.4 - 3.6%. Expression of osteoblast-related genes after 14 days was increased by 1.4-4.8 times. Furthermore alkaline phosphatase activity and calcium ion quantity in cell lysates were increased by 2 and 2.7 times. It was accompanied by extracellular matrix mineralization. The results indicate that rhBMP-2 fully retains its activity inside the collagen-based material. The use of rhBMP-2 at a concentration of 1 μg/ml was ineffective and unable to induce osteogenic differentiation of MSCs. An effective osteoinductive concentration of rhBMP-2 was determined as 10 μg/ml. © Published under licence by IOP Publishing Ltd

Osteoinductive moldable and curable bone substitutes based on collagen, bmp-2 and highly porous polylactide granules, or a mix of hap/β-tcp

In dentistry, maxillofacial surgery, traumatology, and orthopedics, there is a need to use osteoplastic materials that have not only osteoinductive and osteoconductive properties but are also convenient for use. In the study, compositions based on collagen hydrogel were developed. Polylactide granules (PLA) or a traditional bone graft, a mixture of hydroxyapatite and β-tricalcium phosphate (HAP/β-TCP), were used for gel filling to improve mechanical osteoconductive properties of compositions. The mechanical tests showed that collagen hydrogels filled with 12 wt% highly porous PLA granules (elastic modulus 373 ± 55 kPa) or 35 wt% HAP/β-TCP granules (elastic modulus 451 ± 32 kPa) had optimal manipulative properties. All composite components were cytocompatible. The cell’s viability was above 90%, and the components’ structure facilitated the cell’s surface adhesion. The bone morphogenetic protein-2 (BMP-2) provided osteoinductive composition properties. It was impregnated directly into the collagen hydrogel with the addition of fibronectin or inside porous PLA granules. The implantation of a collagen hydrogel with BMP-2 and PLA granules into a critical-size calvarial defect in rats led to the formation of the most significant volume of bone tissue: 61 ± 15%. It was almost 2.5 times more than in the groups where a collagenfibronectin hydrogel with a mixture of HAP/β-TCP (25 ± 7%) or a fibronectin-free composition with porous PLA granules impregnated with BMP-2 (23 ± 8%) were used. Subcutaneous implantation of the compositions also showed their high biocompatibility and osteogenic potential in the absence of a bone environment. Thus, the collagen-fibronectin hydrogel with BMP-2 and PLA granules has optimal biocompatibility, osteogenic, and manipulative properties. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Comparison of Impregnated Bone Morphogenetic Protein-2 Release Kinetics from Biopolymer Scaffolds

The purpose of this study was to evaluate the release kinetics of impregnated recombinant human bone morphogenetic protein-2 (rhBMP-2) from different engineered scaffolds. Poly(lactide-co-glycolide) (PLG) matrices prepared by supercritical fluid technologies (SCFT) showed the highest biocompatibility and long-term release of rhBMP-2. There was an even release of rhBMP-2 from them for 11 days. The subsequent use of laser sintering allowed delaying the peak of the protein release for a period of 13 to 15 days. The average loss of rhBMP-2 using SCFT did not exceed 20%. The maximum release of rhBMP-2 from a collagen-fibronectin hydrogel was in the period from 4 to 6 days. But 47 ± 12% rhBMP-2 loss was shown. Highly porous polylactide-based scaffolds obtained by freeze-drying were inferior to other scaffolds in their ability to release rhBMP-2 for a prolonged period. The hydrogel and chitosan-based granules showed high cytotoxicity and a short period of protein release