Paper-Based Microfluidic Device with a Gold Nanosensor to Detect Arsenic Contamination of Groundwater in Bangladesh

Abstract

Abstract:In this paper, we present a microfluidic paper-based analytical device (µPAD) with a gold nanosensor functionalized with α-lipoic acid and thioguanine (Au-TA-TG) to detect whether the arsenic level of groundwater from hand tubewells in Bangladesh is above or below the World Health Organization (WHO) guideline level of 10 µg/L. We analyzed the naturally occurring metals present in Bangladesh groundwater and assessed the interference with the gold nanosensor. A method was developed to prevent interference from alkaline metals found in Bangladesh groundwater (Ca, Mg, K and Na) by increasing the pH level on the µPADs to 12.1. Most of the heavy metals present in the groundwater (Ni, Mn, Cd, Pb, and Fe II) did not interfere with the µPAD arsenic tests; however, Fe III was found to interfere, which was also prevented by increasing the pH level on the µPADs to 12.1.The µPAD arsenic tests were tested with 24 groundwater samples collected from hand tubewells in three different districts in Bangladesh: Shirajganj, Manikganj, and Munshiganj, and the predictions for whether the arsenic levels were above or below the WHO guideline level agreed with the results obtained from laboratory testing. The µPAD arsenic test is the first paper-based test validated using Bangladesh groundwater samples and capable of detecting whether the arsenic level in groundwater is above or below the WHO guideline level of 10 µg/L, which is a step towards enabling the villagers who collect and consume the groundwater to test their own sources and make decisions about where to obtain the safest water.

Features in Microfluidic Paper-Based Devices Made by Laser Cutting: How Small Can They Be?

“…Microfluidic paper-based analytical devices (µPADs) are an increasingly popular platform for medical diagnosis [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ], environmental testing [ 14 , 15 , 16 ] such as monitoring the quality of water [ 17 ] and soil [ 18 ], detection of pathogens [ 19 , 20 ], metal-ion [ 21 ], pesticides in beverage and food [ 22 , 23 , 24 ], explosives [ 25 ], and other applications, such as the development of paper-based electronics [ 26 , 27 ]. One of the main advantages of µPADs is the capacity for low cost and portable diagnostic devices [ 28 ] for people who do not have access to traditional lab-based medical diagnosis, particularly in resource-poor regions, and for point-of-care devices.…”

A Review of Microfluidic Detection Strategies for Heavy Metals in Water

“…This interference could be overcome by adjusting the pH of the water samples to 12.1. In addition, good correlation between the method's performance and ICP-OES measurements was obtained [79].…”

A Comprehensive Review of Microfluidic Water Quality Monitoring Sensors

“…However, these μPADs were not tested against groundwater samples. When a similar implementation was tested with groundwater samples, the interference from several naturally occurring metals was observed [142]. To eliminate this limitation, Chowdury et al [142] developed a T-shaped μPAD using the same functionalized gold nanoparticles (Au–TA–Au) as illustrated in Figure 7d.…”

“…When a similar implementation was tested with groundwater samples, the interference from several naturally occurring metals was observed [142]. To eliminate this limitation, Chowdury et al [142] developed a T-shaped μPAD using the same functionalized gold nanoparticles (Au–TA–Au) as illustrated in Figure 7d. Additionally, they adjusted the pH value of the water sample to avoid other metal interferences.…”

“…( a ) Wax-printed μPADs for colorimetric detection of Fe, Cu, and Ni [172]; ( b ) 3-D paper microfluidics for metal ion detection [138]; ( c ) working principle of As(III) detector based on modified AuNP [141]; ( d ) T-shaped μPAD with functionalized AuNp for As(III) detection [142]; and ( e ) rapid detection of Pb 2+ with MUA-modified AuNP [140]. …”