Biocompatible Silicon-Based Hybrid Nanolayers for Functionalization of Complex Surface Morphologies

Abstract

Silicon-based polymers show great promise for various applications in biomedicine, nanotechnology, tissue targeting, and drug delivery. The use of such materials as functional coatings on surfaces requires the development of strongly adhering and flexible conformal films, which is challenging for conventional wet-chemical coating techniques. We have developed a facile, solvent-free molecular layer deposition (MLD) process to grow environmentally stable hybrid alumosilazane thin films. Exceptionally good biocompatibility is testified with significantly higher proliferation of human embryonic kidney (HEK293T) cells than that on glass, which was used as a reference. Such highly biocompatible and conformal films show great promise as functional coatings for scaffolds or implantable devices with complex topologies or high-aspect-ratio structures.

Applications of soft biomaterials based on organic and hybrid thin films deposited from the vapor phase

“…The biocompatibility of the alumosiloxane and alumosilazane thin films was tested via the proliferation of human embryonic kidney (HEK293) cells, which proved significantly higher on the MLD thin films than on the reference glass substrates after six days of culturing, forming a uniform and coherent biofilm (figure 3). A higher concentration of cells was found on the alumosiloxane films, which was attributed to the higher surface hydrophobicity, as wettability affects the adhesion of different types of cells to the surface differently [84]. The findings suggest that the hydrophobicity and therefore the cell attachment could be tunable by varying the organosilicon block length using different siloxane or silazane monomers.…”

“…The synthesis of silicon-based polymer thin films by MLD has also been investigated, for example for silicon oxycarbide (Si 2 O 4 C), which has been demonstrated to be stable to air, water, ethanol, hydrochloric acid, and sodium hydroxide, suggesting stability to an even wider range of acids, bases and solvents [81]. In 2020, the group of Mato Knez introduced a 'ring-opening' reaction mechanism to MLD, demonstrated this mechanism for the synthesis of Si-based polymers and studied their biocompatibility [77,[82][83][84]. In this fashion, alumosilazane (SiAlCNH) [84] and alumosiloxane (SiAlCOH) films [83] have been deposited.…”

“…In 2020, the group of Mato Knez introduced a 'ring-opening' reaction mechanism to MLD, demonstrated this mechanism for the synthesis of Si-based polymers and studied their biocompatibility [77,[82][83][84]. In this fashion, alumosilazane (SiAlCNH) [84] and alumosiloxane (SiAlCOH) films [83] have been deposited. The biocompatibility of the alumosiloxane and alumosilazane thin films was tested via the proliferation of human embryonic kidney (HEK293) cells, which proved significantly higher on the MLD thin films than on the reference glass substrates after six days of culturing, forming a uniform and coherent biofilm (figure 3).…”

Atomic/Molecular Layer Deposition for Designer's Functional Metal–Organic Materials

“…[ 31,32,39–44,176,181–200 ] In recent years, the organic precursor library has been rapidly expanding. We have collected in Table 1 the organic precursors so far used in ALD/MLD processes, together with the heating temperatures employed for their evaporation in the corresponding process conditions; [ 17,18,32,40,46,51,57–59,61,63,64,66,81,105–108,114,118,119,121,122,125,129,134–136,139,141,142,156,164,168,189,201–284 ...…”

“…[ 111,231,287–332 ] However, TMA works very well with many other organics as well. [ 40,46,54,108,109,114,125,148,211–213,218,219,221,226,228,230,234,240,244,245,249,252,255,256,258,260,262,264,267–269,273–277,279–284,325,333–369 ] The bulkier dimethyl aluminum isopropoxide precursor has been successfully used with EG as well. [ 323 ] Different TMA + organic processes have been investigated, e.g., to elucidate the effect of the organic backbone length, i.e., long (1,10‐decanediol) or short (1,6‐hexanediol), on the mechanical properties; indeed, as expected, with the increasing chain length, the stretchability was enhanced.…”