According to the researchers, the nanotechnology resides in the biosensing division, while the smartphone with lens could form the microscope section. Therefore, the basic design of the apparatus is of a biosensing tool fused with a simple microscope that has the ability to read the results. The study actually describes the development process of a high-performing biosensing system that combines optical diffusion of nano holes with silver marking.
The apparatus will function like a normal diagnostic tool but it will find out the consequence of a chemical reaction between a molecule and a pathogen to which the former bonds distinctly. The latter, here, can be a bacterium or a virus, while the molecule can be an antibody to fight against the disease. The diagnostic mechanism will allow the reaction to take place after which it will detect the result in such a way that there is no confusion with any other.
However, the challenge is to develop the system in a manner that ensures quick, effortless, and affordable functioning from two sides namely, Biosensing side so that the reaction is allowed to happen distinctly and from the interpretation side for better analysis of the results. Keeping in mind the biosensing side, the researchers have designed a plain glass slide as well as a thin gold film containing thousands of transparent nano holes, each of 600 nanometers. This design itself is a great achievement for them, as it had to pass many phases, such as cutting the ‘interference fringes’ with lasers, which were present on a plate having photo-resist material, cleansing it, and exposing it to vanished gold.
During the study, a platform was set to populate the holes with bacteria and viruses and let the chemical reactions occur inside these nano holes. Nevertheless, this gave rise to one more challenge – The reaction of pathogens with antibodies as well as some extra ingredients did not have adequate bondage to block the light out.
According to Prof. Richard Willson who belongs to the University of Houston, “The ingredient that binds to the antibody is perhaps not huge and grey enough to make this hole shady, so you need to find a way for it.” Luckily, the way of darkening the hole was found - Using antibodies that have enzymes forming silver particles when reacted to a few chemicals. One can now have the required diagnosis: Placing a pathogen sample on the slide, washing the slide in a solution full of antibodies reacting uniquely, and shining a light via holes. This, if resulted in blocking the holes, tends to give a positive result.
This new apparatus is brainchild of Jiming Bao and Richard Willson, both being the professors at the University of Houston in Texas. They have recently written about nanotechnology biosensing mechanism, which was also published in the ACS Photonics Journal.
Now, only a microscope is required, which can peep into the holes and find out which ones do not allow light. Prof. Willson affirms that a standard microscope used in schools can be useful here. In this way, the researchers showed how a smartphone system could be a part of nanotechnology to find contaminants for evaluating the danger rapidly.