New types of hybrid organosilane fibrous scaffolds prepared via electrospinning and 3D printing technologies focused on applications in the field of regenerative medicine

Currently, there is a whole range of so-called hybrid organic-inorganic (nano)fibrous materials, which are formed by mixing organic components (organic polymers such as polyvinyl alcohol-PVA, polyvinyl butyral-PVB, polyhydroxybutyral-PHB, polycaprolactone-PCL, polyvinylpyrrolidone-PVP, etc.) and inorganic components in the form of various types of alkoxides such as (silicon, titanium, aluminum, zirconium, etc.) using various technologies, including electrospinning. The above-mentioned materials find potential applications or are already used in a wide range of industries and in everyday life. These cover mainly the areas of optoelectronics, sensors, energetics, water and/or air filtration, catalysis, automotive industry, textile industry, and especially medicine. However, their great disadvantage is that many of these (nano)materials are formed under relatively complex conditions (economic and environmental), or with the use of toxic substances, especially low polarity, non-polar or highly non-polar organic solvents, various additives, organic polymers, surfactants, etc. Subsequently, it is problematic to use these (nano)materials in the medical field, where the highest emphasis is placed on the cytocompatibility, biocompatibility and non-toxicity of the prepared (nano)materials both in vitro and in vivo. In addition, such types of (nano)materials face a number of problematic properties such as mechanical and thermal resistance, changes in chemical or physical properties due to a number of external factors from the common environment. However, all the above-mentioned parameters can be achieved very effectively by preparing truly hybrid organic-inorganic nanofibers prepared from appropriately selected types of organosilane precursors without the need for application of supporting agents such as organic polymers, additives, surfactants or highly toxic organic solvents together with using ecologically and economically efficient process of their preparation. Our proposed technology regarding the preparation of such types of (nano)fibrous hybrid materials involves the use of four basic components, i.e. water, mineral acid, alcohol and a suitable type of organosilane (organo-mono-silylated or organo-bis-silylated precursor). These components can be efficiently processed by a very simple and economically acceptable, acid-catalyzed sol-gel method to form a spinning solution, which can be very easily transferred by electrospinning technology to the world's unique pure hybrid organosilane (nano)fibers with high cytocompatibility (reaching up to 99%) with almost zero toxicity while maintaining very interesting material properties, such as good mechanical and thermal resistance, conductivity or optical activity. The pure hybrid organosilane (nano)fibers prepared in this way can be further processed efficiently, for example, using cryomilling technology and thus can be used as "carriers" of organic biomaterials such as chitosan, gelatin or alginates prepared in the form of hydrogels. If these cryomilled (nano)fibers are added to these types of biomaterials (hydrogels), they can be used for 3D printing technology to prepare completely unique types of fully biocompatible bioorganic-hybrid hydrogel scaffolds suitable for a wide range of tissue engineering and regenerative medicine applications. Thanks to their multifunctional properties, these types of completely unique systems show a wide field of activity for a wide range of cell lines, from basic fibroblasts to very complex and complicated cell lines such as cardiomyocytes or nervous tissue cells. Proof that these are completely unique types of fibrous (nano)materials is the currently accepted European patent application for the above-described preparation of purely hybrid organosilane (nano)fibers without any additives facilitating the electrospinning process (PS4427EP; 11/2021). The established cooperation with the group of Professor Aldo R. Boccaccini from Friedrich-Alexander-University Erlangen-Nürnberg has enabled us and allows us to further deepen and develop the above-mentio