Biotechnological Utilization of Amazonian Fruit: Development of Active Nanocomposites from Bacterial Cellulose and Silver Nanoparticles Based on Astrocaryum aculeatum (Tucumã) Extract

Abstract

Background/Objectives: The rise of bacterial resistance and the search for alternative, biocompatible antimicrobial materials have driven interest in natural-based nanocomposites. In this context, silver nanoparticles (AgNPs) have shown broad-spectrum antibacterial activity, and bacterial cellulose (BC) is widely recognized for its high purity, hydrophilicity, and biocompatibility. This study aimed to develop a bio-based BC-AgNP nanocomposite via green synthesis using Astrocaryum aculeatum (tucumã) extract and assess its antimicrobial performance for wound dressing applications. Methods: BC was biosynthesized via green tea fermentation (20 g/L tea and 100 g/L sugar) and purified prior to use. AgNPs were obtained by reacting aqueous tucumã extract with silver nitrate (0.1 mmol/L) at pH (9) and temperature (40 °C). BC membranes were immersed in the AgNPs dispersion for 7 days to form the nanocomposite. Characterization was performed using UV-Vis, DLS, TEM, SEM-EDS, FTIR, XRD, ICP-OES, and swelling analysis. Antibacterial activity was evaluated using the disk diffusion method against Staphylococcus aureus and Escherichia coli (ATCC 6538 and 4388). Results: The UV-Vis spectra revealed a gradual decrease in the surface plasmon resonance (SPR) band over 7 days of incubation with BC, indicating progressive incorporation of AgNPs into the membrane. ICP analysis confirmed silver incorporation in the BC membrane at 0.00215 mg/mL, corresponding to 15.5% of the initial silver content. Antimicrobial assays showed inhibition zones of 6.5 ± 0.5 mm for S. aureus and 4.3 ± 0.3 mm for E. coli. Conclusions: These findings validate the successful formation and antimicrobial performance of the BC-AgNP nanocomposite, supporting its potential use in wound care applications.

Keywords: bacterial cellulose; green chemistry; silver nanoparticles.

Figure 1

AgNPs dispersion at (A) time zero and (B) after 3 days of reaction.

Figure 2

(A) Transmission electron microscopy of AgNPs (scale bar = 50 nm). (B) Dynamic light scattering of AgNPs dispersion. On the right is the table referring to the EDS analysis.

Figure 3

UV–Vis spectrum (black) of silver nanoparticles synthesized from tucumã plant extract, (red) BC–AgNP nanocomposite after 1 day of agitation, (dark blue) after 3 days of agitation, (green) after 5 days of agitation, (light blue) after 7 days of agitation, and (orange) after 9 days of agitation.

Figure 4

Fourier transform infrared spectrum—(black) AgNPs synthesized from tucumã extract, (red) tucumã plant extract only, (blue) bacterial cellulose, (green) BC–AgNP nanocomposite.

Figure 5

XRD spectrum—(black) pure BC and (red) BC–AgNP nanocomposite.

Figure 6

Schematic representation of the interaction between light and the BC–AgNP nanocomposite during the reaction period, illustrating the progressive immobilization of silver nanoparticles within the bacterial cellulose matrix.

Figure 7

(A,B) Scanning electron microscopy images of BC and BC–AgNP, respectively. (C) Color change of the bacterial cellulose membrane, and (D) EDS analysis of the membrane with incorporated AgNPs.

Figure 8

Assessment of antimicrobial activity using the disk diffusion method on agar plates against (A1–A3) Staphylococcus aureus and (B1–B3) Escherichia coli.