Candida albicans is an opportunistic fungus that becomes pathogenic and problematic under certain biological conditions. C.albicans may cause painful and uncomfortable symptoms, as well as deaths in immunocompromised patients. Therefore, early detection of c.albicans is essential. However, conventional detection methods are costly, slow and inaccessible to women in remote or developing areas. To address these concerns, we have developed a wearable and discrete naked-eye detectable, colorimetric platform for c.albicans detection. With some modification, this platform is designed to be directly adhered to existing feminine hygiene pads. Our platform is rapid, inexpensive, user-friendly, disposable and only requires three steps: i) addition of vaginal fluid onto sample pads; ii) addition of gold nanoparticle gel and running buffer, and iii) naked eye detection. Our platform is underpinned by selective thiolated aptamer-based recognition of 1,3-β-D glucan molecules- a hallmark of c.albicans cell walls. In the absence of c.albicans, wearable sample pads turn bright pink. In the presence of c. albicans, the wearable pads turn dark blue due to significant nanoparticle target-induced aggregation. We demonstrate naked eye colorimetric detection of 4.4 ×106 c.albicans cells per ml. We believe that this proof-of-concept platform has the potential to have a significant impact on women’s health, globally.

The green synthesis of metallic nanoparticles is an emerging and promising field owing to its environmentally friendly nature and diverse applications. In this article, a new technology for the green synthesis of functional ultrastable biopolymer gold nanoparticles is introduced. This approach employs thiolated single-stranded DNA (ssDNA-SH) aptamers instead of conventional self-assembled monolayers, resulting in the production of highly stable aptamer-tagged gold-core-shell nanoparticles. A comprehensive discussion on the use of glucose as a simple reducing agent for the green synthesis of Au nanoparticles and the utilization of ssDNA-SH aptamers as smart and biologically functional capping agents is provided. The potential of this innovative approach for the green synthesis of nanoparticles is demonstrated through a case study involving the use of the naked eye for qualitative detection of human fungal infections caused by Candida albicans for women's health.