## 4 Results
The FTIR spectra of the resulting systems showed the superpositions of the vibrational bands of the hybrid nanocomposites and polymeric matrix, thus confirming the incorporation of dioxidine or gentamicin sulfate into the biopolymer matrices. The wide bands attributed to chitosan (580 cm\({}^{-1}\)), gelatin (534 cm\({}^{-1}\)), and Ca-alginate (550 cm\({}^{-1}\)) overlapped several narrower bands corresponding to dioxidine. The \({}^{1}\)HNMR spectra of the substances released from the hybrid depot nanoforms in D\({}_{2}\)O were similar to \({}^{1}\)HNMR spectra of individual dioxidine or gentamicin sulfate. The UV spectra of aqueous extracts of the Ag/dioxidine/gelatin, Ag/dioxidine/chitosan, Ag/dioxidine/Ca-alginate, Cu/dioxidine/gelatin, Cu/dioxidine/chitosan, and Cu/dioxidine/Ca-alginate systems were corresponded to the UV-visible spectra of dioxidine. It was shown that loading of the cryogenically structured wide-porous polymeric matrices with antibacterial drugs and metal nanoparticles did not significantly affect the pore size distribution of the biopolymeric carriers, thus suggesting that dioxidine and gentamicin sulfate were in a highly  
Figure 1: TEM micrographs and selected area electronic diffraction (SAED) patterns of hybrid composites of dioxidine with silver nanoparticles (**a**), gentamicin sulfate with copper nanoparticles (**b**). Kinetic curves of the release of dioxidine and gentamicin sulfate from hybrid nanoforms obtained by cryogenic structuring of biopolymeric matrices and after their uploading by cryoformed nanocomposites of antibacterial drugs with metal (Ag or Cu) nanoparticles are presented in (Figure 4). The release of antibacterial drugs from the Ca-alginate matrix took 40 min (Figure 4a; dioxidine, curve 1; gentamicin sulfate, curve 2), and from gelatin, 60 min (Figure 4b; dioxidine, curve 1; gentamicin sulfate; curve 2). The release of antibacterial drugs from the chitosan matrix (Figure 4c; dioxidine, curve 1; gentamicin sulfate, curve 2) took almost three days. The data obtained indicate the presence of stronger specific interactions between the chitosan matrix and antibacterial drugs than in the case of other two matrices. However, the complete release of the loaded antibacterial drug from the chitosan matrix within three days allows us to exclude the covalent binding of drug components by the active functional centers of the chitosan biopolymer matrix. Thus, in this case, we can see a prolonged action of drug components preliminarily loaded in the nanoform with metal nanoparticles incorporated into the cryogenically structured biopolymeric sponges due to the specific intermolecular interactions. Changing the structure of the spongy carriers by varying the nature of core biopolymer and the conditions of their cryogenic formation can allow us to reduce the release rate more for the antibacterial drugs (dioxidine and gentamicin sulfate) from the hybrid nanoforms based on gelatin and Ca-alginate and to obtain a longer-lasting effect of controlled release of the drug component. We determined the antibacterial activity of dioxidine and dioxidine-based hybrid nanosystems against _E. coli 52_ and _S. aureus 144_ bacteria. The data obtained are presented in Figures 5-7 and are given in more detailed form in Tables 11 and 12. The antibacterial activity of the hybrid composites of metal nanoparticles with dioxidine appeared to be higher than that of individual nanoparticles of metals and dioxidine in the antibacterial tests using standard disks of Ca-alginate and gelatin-based biopolymer matrices. In the case of chitosan-based biopolymer matrix: The use of hybrid nanocomposites resulted in lower antibacterial activity, relative to the individual dioxidine. Chitosan-based sponges probably differ not only in higher specific interactions of dioxidine molecules with cryostructured biopolymer carrier but also in the stronger interactions of metal nanoparticles themselves with biopolymer carrier.