Experimental and theoretical work carried out by many leading physicists, including Albert Einstein, at the beginning of the 20th century, changed the way we understand the nature of light. It was shown that light consists of a fundamental particle, called a photon, which can be seen as a packet of light or radiation. While light is commonly associated with the visible colours seen in everyday life, it consists of a wide range of frequencies divided into different regions, for example, X-ray radiation, Ultraviolet radiation, Visible light and Infrared radiation, all part of the electromagnetic spectrum. The various regions of the electromagnetic spectrum will interact with matter in significantly different ways. The main interaction of light with matter consists of, energetic ejection or excitation of core electrons, excitation of molecular and atomic valence electrons, molecular electron excitation, molecular vibration or rotation. The outcome of these interactions with matter leads to transmission, reflection or an absorption process that may lead to a re-emission of light. For example, the interaction of visible light and leaves on vegetation leads to both a reflection (typically a green colour) and absorption due to chlorophyll, a common molecule found in plants. By using these interactions of light and matter, it is possible to probe the atomic and molecular structure of matter and falls within the field of spectroscopy.
Biocompatible Fluorescent Nano – Diamonds
The standard biomarkers commonly used for flow cytometry or fluorescence microscopy, such as Propidium Iodide or Ethidium Bromide, cannot be used in applications where health issues or toxicity are a concern. For this reason, we employ biocompatible FND. In contrast to organic dyes, which suffer from photobleaching, photoblinking, cytotoxicity and limiting shelf lifetime, FNDs are non-photobleachable even under continuous, long-term high-power illumination, they are structurally and chemically stable and they are not cytotoxic. Surface functionalisation of FNDs, allowing selective fluorescent marking, is possible to realise by specific chemical treatment. In order to enhance fluorescence intensity we are employing ion implantation technique followed by diamond irradiation by high energy particles or radiation, usually at energy of 30keV or higher.
Nano Letters, 17, 3465-3470, 2017
Molecular Imprinted Polymer
Molecularly imprinted Polymers (MIPs), first theorized in the mid-eighties are a synthetic molecular recognition tool that can be designed to specifically detect target molecules, macromolecules or even bacteria such as E. coli. MIPs are synthesized using cross polymerization techniques in conjunction with target molecules such that a specific target-polymer binding site is created. This binding site is sterically and chemically functionalized to bind to the unique target. In turn, molecular recognition and binding are highly specific to the target, even in a diverse chemical soup environment. MIPs share similar functionality to those of antibodies and enzymes, with the benefit that MIPs have the capability to become biomimetic sensors. MIPs compare very favourably to antibodies and enzymes, in that MIPs are cheaper to produce, more stable and more customizable. MIPs do not require tightly controlled environments that enzymes and antibodies mandate for stability and reactivity purposes. MIPs are further superior to enzymes and antibodies in their reusability, in that costly purification and salvage techniques are not required. The focus of this work is to couple MIPs with spectroscopic sensing techniques to provide low cost, real-time and portable detection of various hazardous molecules in a range of environments.