All invasive procedures in volve the contact of a medical device or surgical instrument witht hepatient's sterile tissue or mucosal surfaces. At this point, the greatest risk is that pathogenic microorganism senter the body and cause infection. In our country, such invasive procedure sarefre quently performed in gastroenterology clinics and their cost is quite high. For this purpose, nanoparticles were synthesized with orthophtaldehyde (OPA), which is important in sterilization in the seclinics, and it is aimed to increase the sterilization efficiency of the nanocomposite obtained by reducing the amount of orthophtaldehyde use. OPA silver and graphenoxide nanoparticles were synthesized and their effective diameters (hydro dynamic diameters) and surface charges were determined by dynamic light scattering (DLS) and Zetapotential (ZT) measurements, respectively. Antimicrobial activities of orthophtaldehyde and nanocomposites against Staphylococcusaureus (S. aureus) ATCC 25923, Escherichiacoli (E. coli) ATCC 35218 and Candidaalbicans (C. albicans) ATCC 90028 standard strains were calculated by percent inhibition method using liquid microdilution method.OPA@AgNPs were determined to be 10-25 nm in size by STEM. OPA@AgNPandOPA@Ag@GONKs was determined as ~430 and ~415 nm absorbance peaks, respectively. The surface charges of OPA@AgNPandOPA@Ag@GONKs were determined as -33 m Vand -46 mV, respectively. The hydrodynamic diameter of OPA@Ag@GONKs was measure daround 1250 nm. Graphenoxide is a negatively charged material. When negatively charged OPA@AgNPs (-33 mV) were formed on it, the surface charge of the new material OPA@Ag@GONKsincreased to -46 mV. The results are compatible withe ach other. Although C.albicansis at a higher rate, it is seen that there is a significant difference (p<0.001) between OPA@Ag@GONK, OPA@AgNP and OPA in all tested micro organisms, respectively. Thesyn the size dnano composites are the first to be synthesized from OPA. However, it is also important in terms of having a higher antimicrobial activity than the use of OPA alone. In this context, nanocomposites synthesized using OPA can reduce the use of chemicals and allow a more effective dis infection with less active substance.