Glass surfaces, although the first to be used for culturing ex vivo adherent cells, are not the perfect substrates for this purpose. Today, plastics dominate these applications, but in light of the global trend to reduce the use of synthetic polymers, it is reasonable to consider a return to glass vessels with coatings for these purposes. The ideal surface for cell growth is one that simulates the composition and structure of the mainly protein-based intercellular matrix. The work presented here shows a new idea of preparing porous protein coatings on glass using biosynthesis. The process utilizes the colonization of the gold nanoparticle-coated glass surface with Lactobacillus rhamnosus GG bacteria, followed by permeabilization (using ethanol) of their membrane and partial thermal degradation (at 160 °C in vacuum) of the surface-bound protein components of these microorganisms. It results in a development of coating on the glass that promotes mammalian cell growth, which has been preliminary confirmed using Vero cells. Subsequent steps in the formation of coating components were documented by reflectance ultraviolet and visible spectra and infrared spectroscopy. The presence of microorganisms and mammalian cells was confirmed using scanning electron and optical microscopy and crystalline violet staining.