Dielectica traverses through the literature on this topic – and summarizes as they appear.
Correspondence prepared by: Dr. Md Palashuddin Sk, Assistant Professor of Aligarh Muslim University, Uttar Pradesh, India, email: palashuddin.ch@amu.ac.in (12:10:2020, 17:30)
Key Words: Haemoglobin, Carbogenic Dots, luminescence, nanocrystals
Aligarh: Haemoglobin (Hb) is an essential iron-containing protein, which exists in the red blood corpuscles. Hb consists of four iron-porphyrin units (heme) together with the globular protein moiety. Atomic iron encaged into the heme moiety plays a crucial role in transporting molecular oxygen (O2) from the respiratory organs to the different parts of our body through blood and carrying the major portion of carbon dioxide from these parts to the lungs at the same time. The Hb level in blood to the well-functioning of the organism in the human body is 13.0-18.0 g/dL and 12.0- 16.0 g/dL for male and female, respectively [1]. On the contrary, Hb amount below this level solely causes several blood disorder diseases (even fatality) such as thalassemia, anaemia, and leukaemia. Approximately, two billion people (mainly women and children), worldwide suffer from particular anaemia due to the lower level of Hb in blood. The lower level of Hb thus becomes a major issue and hence is of substantial significance for clinical diagnosis purposes. In this regard, the sensitive detection and determination of Hb in clinical diagnostics is essential to assess the extent of blood disorder diseases and to evaluate various intervention programs aimed at control of the same.
There are quite a few analytical methods like electrochemical, colorimetric, and various spectroscopic techniques are generally employed for the detection of Hb in the blood. Unfortunately, most of these techniques require harsh, expensive chemicals, tedious and complicated probe preparation and of low sensitivity detection ability as well. In this scenario, the luminescent carbogenic dots (Cdots) are paid great attention due to their higher water solubility, biocompatibility, high quantum yield, and excellent optical (stability towards the chemical/physical environment changes such as pH, ionic strength, etc.) and well enough chemical stability.
Following this trend, our Research Group at Aligarh Muslim University, India, has recently developed a Hb sensor from the reaction by-product, which is accidentally isolated during the synthesis of tin oxide (SnO2) nanocrystals [1]. The purified by-product is confirmed as luminescent carbogenic dots which is again produced due to the polymerization and consequent carbonization of the excess of 4,7,10-trioxa-1,13-tridecanediamine (TTDDA). Yet, TTDDA is a hazardous reagent, it is used as a stabilizing agent in metal nanocrystals synthesis [1]. The advantage of such synthesis lies in the fact that the obtained product SnO2 nanocrystals and the reaction side product are environmentally friendly and are produced through the sustainable way. Our Research Group has actually employed the principle of luminescence turn-off property of Cdots with the interaction of Hb to develop a diagnostic method for qualitative and quantitative detection of Hb in the blood. The observed luminescence property of the Cdots remains highly selective towards the detection of a trace amount of Hb. Efficient ground state complexation between Cdots and Hb is solely responsible for the unprecedented selectivity of Cdots towards Hb detection. Keeping in mind the issues of accuracy in the visual detection, economic factors and the portability, we have further developed a fluorescent test strip-based sensing method. The rapid sensing experiment by using the fluorescent test strip has also been studied with the voluntary collection of blood samples, and various interfering chemical substances, proteins, amino acids, metal ions, anions, etc at pH ~7.4 in order to realize the selectivity as well. Upon addition of Hb, the emission intensity of Cdots is drastically reduced; while, in the case of other analytes addition, hardly any reasonable change in the intensity observed, validating the accuracy of the test strip. Test strip-based luminescence turn-off property of Cdots in the presence of Hb further defines their applicability in fabricating portable and inexpensive sensing devices. Even the trace amount of blood present in the human urine is also possible to be detected by this paper-based method, the author stated. The present paper strips based detection technique has advantages over conventional methods (absorption-based spectroscopic methods) because of the portability, cost-effectiveness, time-saving, high sensitivity, ease to measuring Hb, requiring minimum instrumentation and so forth. The user-friendly nature of this technique is quite desirable and beneficial mainly in the remote areas or primary health care centres to monitor the Hb level of patients.
Sources:
[1] F. Arshad et. al., New J. Chem., 44, 6213 (2020)
https://pubs.rsc.org/en/content/articlelanding/2020/nj/d0nj00401d#!divAbstract