1 Introduction
Water pollution refers to the deterioration of water quality due to the presence of
toxic components present in water. It has become a major widespread problem that
has affected everyone globally. The problem of water pollution has been faced by
both the developed and developing nations where the mortality rate caused due to
water pollution appears to be quite high [1]. There are numerous factors which are
affecting the water quality, for example climate change, pesticides and fungicides
used in vegetation, industrial waste dumping/leaching in waterbodies, mining
activities [2]. Nonetheless several techniques like gas chromatography, high performance liquid chromatography, spectrofluorometry, cyclicvoltametry, enzyme
linked immunosorbent assays are available for detecting the water pollutants but a
portable, cheaper, and rapid technique is needed for the detection of the pollutants.
The immunochromatographic strip (ICS) based assay also known as lateral flow
assays (LFA) is a paper-based platform appears to be cheap, rapid and portable tool
for both qualitative and quantitative detection of the pollutants. Earlier ICS based
sensors are mainly used for the detection of specific antigens [3] and antibodies [4],
thereafter a diverse kind of biological samples are being tested using lateral flow
strip, such as urine [5] saliva [6] sweat [7, 8], serum [9] plasma [10] whole blood
[11, 10], and other fluids. Very recently, ICS based sensors are also used in the
environmental monitoring including the detection of different water pollutants, such
as, heavy metals, different organic pollutants, pathogens etc.
1.1 Principle of Immunochromatographic Strip Based
Assay (ICA)
ICA is based on the simple principle that the analyte, which is to be detected, moves
through capillary action along the strip having different zones where various
molecules are attached to interact with the analyte molecules in higher or lower
specificity. Finally, the result will appear as visual observation at the control or test
lines. Intensity of the lines appears on the test line is directly proportional to the
concentration of the analyte [12–14]. Different zones or components of the ICS are
described below.
1.2 Components of Immunochromatographic Strip (ICS)
ICS mainly consist of four components as shown in Fig. 1.
Sample Pad. The sample pad is generally composed of cellulose, glass fiber, rayon
etc. The sample/analyte is first drop casted on this zone of the ICS and then
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M. Pant et al.
Water pollution refers to the deterioration of water quality due to the presence of
toxic components present in water. It has become a major widespread problem that
has affected everyone globally. The problem of water pollution has been faced by
both the developed and developing nations where the mortality rate caused due to
water pollution appears to be quite high [1]. There are numerous factors which are
affecting the water quality, for example climate change, pesticides and fungicides
used in vegetation, industrial waste dumping/leaching in waterbodies, mining
activities [2]. Nonetheless several techniques like gas chromatography, high performance liquid chromatography, spectrofluorometry, cyclicvoltametry, enzyme
linked immunosorbent assays are available for detecting the water pollutants but a
portable, cheaper, and rapid technique is needed for the detection of the pollutants.
The immunochromatographic strip (ICS) based assay also known as lateral flow
assays (LFA) is a paper-based platform appears to be cheap, rapid and portable tool
for both qualitative and quantitative detection of the pollutants. Earlier ICS based
sensors are mainly used for the detection of specific antigens [3] and antibodies [4],
thereafter a diverse kind of biological samples are being tested using lateral flow
strip, such as urine [5] saliva [6] sweat [7, 8], serum [9] plasma [10] whole blood
[11, 10], and other fluids. Very recently, ICS based sensors are also used in the
environmental monitoring including the detection of different water pollutants, such
as, heavy metals, different organic pollutants, pathogens etc.
1.1 Principle of Immunochromatographic Strip Based
Assay (ICA)
ICA is based on the simple principle that the analyte, which is to be detected, moves
through capillary action along the strip having different zones where various
molecules are attached to interact with the analyte molecules in higher or lower
specificity. Finally, the result will appear as visual observation at the control or test
lines. Intensity of the lines appears on the test line is directly proportional to the
concentration of the analyte [12–14]. Different zones or components of the ICS are
described below.
1.2 Components of Immunochromatographic Strip (ICS)
ICS mainly consist of four components as shown in Fig. 1.
Sample Pad. The sample pad is generally composed of cellulose, glass fiber, rayon
etc. The sample/analyte is first drop casted on this zone of the ICS and then
234
M. Pant et al.