“Chemical nose” for the visual identification of emerging ocular pathogens using gold nanostars

• Published in: Biosensors & bioelectronics Vol. 61; pp. 386 - 390
• Main Authors: Verma, Mohit S., Chen, Paul Z., Jones, Lyndon, Gu, Frank X.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.11.2014; Elsevier
• Subjects: Bacteria; Bacteria - isolation & purification; Biological and medical sciences; Biosensing Techniques - instrumentation; Biotechnology; Blindness; Color change; Colorimetry; Colorimetry - instrumentation; Contact lens cases; Fundamental and applied biological sciences. Psychology; Gold; Gold - chemistry; Gold nanoparticles; Humans; Keratitis - diagnosis; Keratitis - microbiology; Microbial keratitis; Nanostructure; Nanostructures - chemistry; Nanostructures - ultrastructure; Nose; Pathogens; Point-of-care; Staphylococcus aureus; Visual; Visual detection; Color change; Microbial keratitis; Point-of-care; Visual detection; Gold nanoparticles; Contact lens cases; Gold; Contact lens; Nanoparticle; Color; Identification; Pathogenic; Microorganism; Detection
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2014.05.045

Ocular pathogens can cause serious damages in the eye leading to severe vision loss and even blindness if left untreated. Identification of pathogens is crucial for administering the appropriate antibiotics in order to gain effective control over ocular infection. Herein, we report a gold nanostar based “chemical nose” for visually identifying ocular pathogens. Using a spectrophotometer and nanostars of different sizes and degrees of branching, we show that the “chemical nose” is capable of identifying the following clinically relevant ocular pathogens with an accuracy of 99%: S. aureus, A. xylosoxidans, D. acidovorans and S. maltophilia. The differential colorimetric response is due to electrostatic aggregation of cationic gold nanostars around bacteria without the use of biomolecule ligands such as aptamers or antibodies. Transmission electron microscopy confirms that the number of gold nanostars aggregated around each bacterium correlates closely with the colorimetric response. Thus, gold nanostars serve as a promising platform for rapid visual identification of ocular pathogens with application in point-of-care diagnostics. •Specific number of gold nanostars electrostatically aggregate around each pathogen.•Aggregation depends on the surface morphology of gold nanostars and bacteria.•Bacteria could be identified with 99% accuracy using a spectrophotometer.