Silver nanoparticles made by bacteria, not by harsh chemistry.
BioSilver RAK uses actinomycete bacteria isolated from local soil to make silver nanoparticles outside the cell. The approach is an eco-friendly route to antimicrobial nanomaterials for research and future antibacterial products.
Antimicrobial silver, made the hard way
Silver nanoparticles are useful antimicrobials, but how they are made matters.
Chemical routes
Conventional synthesis can rely on harsh reagents and energy-intensive steps.
Rising resistance
New antimicrobial materials are needed as bacteria become harder to treat.
Untapped local microbes
Soil bacteria with useful properties often go unscreened.
Let soil bacteria build the particles
BioSilver RAK isolates actinomycetes from soil and uses their extracellular products to reduce silver into nanoparticles.
Soil Streptomyces
- Isolated from campus soil samples
- Identified as Streptomyces species
- PCR band at the expected 602 bp
Extracellular and green
- Made outside the bacterial cell
- Eco-friendly process
- Confirmed by UV-Vis spectroscopy
Characterised nanoparticles
- FTIR peaks at 3325 and 1633 cm⁻¹
- Functional groups suggest biological capping
- Size distribution measured by DLS
How BioSilver RAK works
From a soil sample to characterised nanoparticles.
- 1
Isolate
Actinomycetes are isolated from soil samples.
SoilActinomycetes - 2
Screen and identify
Isolates are screened by cross-streak against test microbes and identified by 16S rRNA PCR.
Cross-streakPCR - 3
Synthesise
Cell-free filtrate reduces silver to nanoparticles outside the cell.
ExtracellularGreen - 4
Characterise
Particles are checked by UV-Vis, FTIR and dynamic light scattering.
UV-VisFTIRDLS
What the laboratory study showed
In vitro isolation, identification and nanoparticle characterisation.
| Test organism | Isolate 1 | Isolate 2 |
|---|---|---|
| Staphylococcus aureus | No inhibition | Good inhibition |
| Bacillus spp. | Partial inhibition | Good inhibition |
| Escherichia coli | No inhibition | No inhibition |
| Candida albicans | No inhibition | No inhibition |
Source: Shivappa et al., American Journal of Biochemistry and Biotechnology 18(3), 300–307 (2022). doi:10.3844/ajbbsp.2022.300.307
Who BioSilver RAK is for
A green nanomaterial platform with research and product uses.
Research laboratories
- Biologically made silver nanoparticles
- Characterised by UV-Vis, FTIR and DLS
- Local Streptomyces strains
Antimicrobial developers
- Candidate material for coatings and dressings
- Green synthesis route
- Activity against Gram-positive bacteria to explore
Educators
- Hands-on green nanotechnology
- Links microbiology and materials science
- Simple, low-cost methods
Where the evidence stands
BioSilver RAK is an early laboratory project.
Screening, not dosing
Antibacterial data are qualitative cross-streak results of the isolates, with no inhibition zone or MIC values for the nanoparticles.
Not active against all microbes
Neither isolate inhibited E. coli or Candida albicans in screening.
No safety data
Toxicity to human cells and use in products have not been studied.
The team
Founded in 2022 by the research team behind the biogenic silver nanoparticle study.
Pooja Shivappa
Co-author of the BioSilver RAK research.
Grisilda Vidya Bernhardt
Co-author of the BioSilver RAK research.
Sheela Haridas
Co-author of the BioSilver RAK research.
Michael V. Magaogao
Co-author of the BioSilver RAK research.
Frequently asked questions
What are biogenic silver nanoparticles?
They are silver nanoparticles made by living organisms, here soil Streptomyces bacteria, instead of by chemical reduction.
Where do the bacteria come from?
They were isolated from local campus soil samples and identified as Streptomyces by 16S rRNA PCR.
How big are the particles?
Dynamic light scattering measured a hydrodynamic size of 91.2 nm.
Do they kill bacteria?
The authors report strong antimicrobial activity, but the published screening data are qualitative and further testing is needed.
Is there a product yet?
No. BioSilver RAK is at the laboratory research stage.
Peer-reviewed science behind BioSilver RAK.
Read the full study behind the product.
Shivappa, P., Bernhardt, G. V., Haridas, S., & Magaogao, M. V. (2022). Biogenic silver nanoparticles produced by bacteria isolated from university campus environment soil samples in Ras Al Khaimah. American Journal of Biochemistry and Biotechnology, 18(3), 300–307.
https://doi.org/10.3844/ajbbsp.2022.300.307