In this study, a mixed sol-gel technique using silicate, polyvinyl alcohol (PVA), and polyethyleneimine (PEI) was used to various polymers based on PEI and silica gel. The c-PEI blend co-polymer was synthesized by cross-linking branching PEI in an aqueous solution with PVA. The produced c-PEI particles were highly positively charged and fit inside the range of tens to hundreds of nanometers of silica gel. It has been shown that the prepared c-PEI nanocomposite is a very effective antimicrobial, anti-inflammatory, and antioxidant material. In addition to the appropriate investigation of the anti-inflammatory activity using human red blood cells (HRBCs) stabilization, the developed materials were used to explore antimicrobial activity against yeast (Candida albicans ATCC-10231), Gram-negative bacterial strain (Escherichia coli ATCC-25922), and Aspergillus niger NRRL-3 as a fungus. FTIR, XRD, TEM, TGA, and DSC were among the biological and chemical methods used to characterize the produced c-PEI nanocomposites. The agar diffusion method was used to assess the biological activity of the synthesized compounds, and the results revealed a range in their in vitro-antimicrobial inhibitory activity. Based on the type of pathogenic microbe, the majority of the test substances showed a wide range of activity. The examined substances may be appropriate for the creation of an innovative antibacterial and antifungal medicinal medication.