Introduction: Antibiotics are not only commonly used as medicine for disease treatments, but also are widely used in additives for animal feeding. Among various antibiotics, tetracycline is the one most widely used as a feed additive for animal disease prevention and treatment due to its wide antimicrobial capability, low cost and good stability. Unfortunately, the abuse of tetracycline, especially in animal feeding, inevitably causes tetracycline residue in animal-origin foods such as meat, eggs and milk, etc., not only causing adverse reactions including abdominal pain, diarrhea, flatulence and vomiting, but also damaging human organs such as the liver and kidney, and even increasing the risk of bacterial resistance. As such, it is important to monitor tetracycline, especially in animal-origin foods
Methods: Various methods have been proposed to detect tetracycline, such as high performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), microbiological testing, capillary electrophoresis, colloid gold immunochromatography assay (CGIA) and enzyme-linked immunosorbent assay (ELISA), etc. HPLC and LC-MS can detect tetracycline in rather high precision and sensitivity, but they require complicated sample pretreatment and time-consuming operations, limiting their applications in rapid detection. While microbiological testing can detect tetracycline with simpler operations and faster speed compared to HPLC and LC-MS, its detecting specificity is poor. Moreover, these methods often rely on huge and expensive instruments, not only increasing the detecting cost, but also limiting their on-site detecting applications
Results: Nowadays, in situ analysis attracts the interests and becomes one of the main purposes in analytical chemistry. Design of portable analysis devices facilitates reaching this goal. An ideal analysis system contains different parts enabling extraction, detection and quantification of target analytes. Preparation of a portable quantification approach is a bottle neck in such system creation. Common lab analysis instruments do not have the transportation ability and using these facilities limits the complete in situ analysis. Smartphones are the modern life phenomena and their usage becomes more widespread, every day. Their abilities and features are also swiftly developed[2].
A smartphone is a facile and handy-analytical device. Due to recent advancements in the technology and the introduction of user friendly operating systems and applications, the smartphones have replaced laptops and desktop computers. Taking this fact into account, researchers have designed sensing systems which are more compatible with smartphones. Consequently, these devices are attracting the attention of researchers from fields such as biotechnology, chemical sciences and environmental sciences
Conclusion: In order to achieve a simple and inexpensive quantitative measurement device for fluorescence intensity detection, ehtesabi et al. used a free Android application (IJ_Mobile application, version 1.1, 2013). To set up a smart fluorimeter sensor, they used a duct gel device was used as the source of ultraviolet radiation. The device is equipped with five ultraviolet lamps of 8 watts, 365 nm, providing a uniform intensity distribution. Also, a filter with 365 nm bandwidth and 20 nm FWHM was used to pass only the fluorescence stimulation wavelength and eliminate other beams. After placing the samples in the gel chamber, photographs were taken using an 8MP camera. In order to remove the backlight, conventional sunglasses were used to filter ultraviolet light up to 410 nm. The images were then processed using the chart option in the IJ_Mobile program, which can be used to compare the emission intensity of different samples simultaneously. Compared with other traditional methods, simplicity of monitoring makes this method a novel and important approach in the detection of tetracycline[4].
Li et al. proposed a handheld inkjet printing paper chip based smart tetracycline detector. Tetracycline can be determined by inkjet printing prepared paper chip based enzyme-linked immunosorbent assay (ELISA) with the advantages of high sensitivity, excellent specificity and low cost. Moreover, a smartphone based paper chip reader and application is designed for automatically determining tetracycline with simple operations, high precision and fast speed. The smart tetracycline detector with a compact size of 154 mm × 80 mm × 50 mm and self-supplied internal power can reach a rather low detection limit of ~0.05 ng/mL, as proved by practical measurements. It is believed the proposed handheld inkjet printing paper chip based smart tetracycline detector is a potential tool in antibiotic sensing for routine uses at home and on-site detection in the field