Electronic Theses and Dissertation

Nanopartikel tembaga (Cu) berpotensi sebagai agen antibakteri, namun sintesis secara konvensional umumnya menggunakan bahan kimia yang kurang ramah lingkungan. Green synthesis dengan memanfaatkan ekstrak tumbuhan menjadi alternatif yang lebih aman karena senyawa metabolit sekundernya berperan sebagai agen pereduksi dan penstabil nanopartikel. Penelitian ini bertujuan untuk mensintesis nanopartikel tembaga menggunakan ekstrak etanol daun sirsak (Annona muricata L.) berbantuan sonikasi, mengkarakterisasi nanopartikel menggunakan spektrofotometer UV-Vis, FTIR, X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS), dan Transmission Electron Microscopy (TEM), serta mengevaluasi aktivitas antibakterinya terhadap Escherichia coli dan Staphylococcus aureus. Keberhasilan sintesis ditunjukkan oleh perubahan warna larutan dan hasil karakterisasi. Spektrum UV-Vis menunjukkan serapan khas oksidasi tembaga yang tumpang tindih dengan serapan senyawa organik, sedangkan analisis FTIR menunjukkan biomolekul ekstrak tetap teradsorpsi pada permukaan nanopartikel sehingga berperan sebagai agen pereduksi dan capping agent. Pola XRD mengonfirmasi terbentuknya fase kristalin CuO sebagai fase dominan yang disertai fase Cu dan Cu₂O. Karakterisasi SEM-EDS menunjukkan morfologi partikel quasi-spherical hingga tidak beraturan dengan kecenderungan membentuk agregat, kandungan Cu sebesar 41,18 wt.% dan O sebesar 4,71 wt.%, sedangkan TEM menunjukkan ukuran rata-rata partikel sebesar 5,46 ± 1,82 nm. Nanopartikel Cu-AMLE (Annona muricata leaf Ethanol menunjukkan aktivitas antibakteri terhadap E. coli dan S. aureus pada konsentrasi 10 dan 20 ppm, sedangkan ekstrak etanol daun sirsak tidak menunjukkan aktivitas antibakteri. Hasil penelitian menunjukkan bahwa metode green synthesis berbantuan sonikasi berhasil menghasilkan nanopartikel berbasis Cu berukuran nano dengan karakteristik yang baik dan berpotensi sebagai agen antibakteri.

Copper nanoparticles (CuNPs) have attracted considerable attention as antibacterial agents. However, conventional synthesis methods generally involve hazardous chemicals that are harmful to the environment. Green synthesis using plant extracts has emerged as an environmentally friendly alternative because secondary metabolites can act as reducing and stabilizing agents during nanoparticle formation. This study aimed to synthesize copper nanoparticles using Annona muricata L. leaf ethanolic extract assisted by sonication, characterize the synthesized nanoparticles using UV-Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS), and Transmission Electron Microscopy (TEM), and evaluate their antibacterial activity against Escherichia coli and Staphylococcus aureus. Successful synthesis was indicated by the color change of the reaction mixture and characterization results. The UV-Visible spectrum exhibited an absorption characteristic of copper oxidation overlapping with the absorption of organic compounds, while FTIR analysis indicated that extract biomolecules remained adsorbed on the nanoparticle surface, acting as reducing and capping agents. XRD analysis confirmed the formation of crystalline CuO as the predominant phase, accompanied by Cu and Cu₂O phases. SEM-EDS analysis revealed quasi-spherical to irregularly shaped particles with a tendency to aggregate, a Cu content of 41.18 wt.% and an O content of 4.71 wt.%, whereas TEM analysis showed an average particle size of 5.46 ± 1.82 nm. The synthesized Cu-AMLE nanoparticles exhibited antibacterial activity against E. coli and S. aureus at concentrations of 10 and 20 ppm, whereas the ethanolic leaf extract showed no antibacterial activity. The results demonstrate that sonication-assisted green synthesis successfully produced Cu-based nanoparticles with nanoscale dimensions, favorable characteristics, and promising potential as antibacterial agents.