Systematic review of green nanotechnology in the Andes: nanoparticle biosynthesis and applications from Chara globularis

Chara globularis, a submerged macroalga widely distributed in the smaller Lake of Titicaca, covers approximately 436 km² over 60% of the vegetated lakebed—forming dense underwater meadows between 5 and 10 meters deep. Its ecological relevance lies in its ability to precipitate calcium carbonate and co-precipitate phosphorus, improving water clarity and modulating nutrient cycling in high-altitude oligotrophic environments. Beyond its ecosystem functions, C. globularis has emerged as a promising bioresource for the green synthesis of metal nanoparticles, offering a sustainable and low-cost alternative to conventional methods. Phytochemical-rich extracts from C. globularis are used to synthesize copper, silver, and gold nanoparticles, with visual colour changes indicating nanoparticle synthesis brown for copper nanoparticles (CuNPs), reddish-brown for silver nanoparticles (AgNPs), and ruby-pink for gold nanoparticles (AuNPs). These biogenic nanoparticles exhibited high stability and functional surface groups, as confirmed by Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), and X-ray Diffraction (XRD) analyses. Their nanoscale size (typically 10–80 nm) and biocompatibility make them suitable for diverse applications in biomedicine (antimicrobial and anticancer therapy), agriculture (nanofertilizers and pest control), and environmental remediation (wastewater treatment and heavy metal removal). This study underscores the dual value of C. globularis as both a keystone species in Andean aquatic ecosystems and a platform for eco-innovative nanotechnology. The successful integration of native biodiversity with advanced material science not only promotes clean technology but also repositions C. globularis as a strategic natural resource for the sustainable development of high-altitude regions like Lake Titicaca. Keywords: green synthesis, macroalga, macrophyte, nanostructures.