|Abstract:||Optical imaging of biomolecules and chemicals has been instrumental in detecting the target of interest for many diverse fields such as biomedicine, nanotechnology, and chemical science. With the recent advances of optical measurement for reflection, absorbance, and fluorescence, highly sensitive analysis to confirm the presence of specific biomolecules that cause diseases and of individual chemicals is achieved. However, conventional imaging methods depend on expensive laboratory-based instruments, and there is an increasing need for advanced sensing techniques that can be conducted regardless of space and time to facilitate the scenario of point-of-care diagnostics (POCD).
To meet the needs, affordable and portable sensing systems are developed using a smartphone. Incorporation of bio/chemical sensing technology into mobile platforms is a potentially powerful development, as assay capabilities that have previously only been available through laboratory instruments may be utilized by anyone. Such developments can help to achieve the goal of POCD in which out-of-laboratory tests may be used for molecular analysis and chemical detection. The systems integrated with a smartphone may also enable diagnostic technology that can be translated to resource-poor regions of the world. The systems, deployed widely, would be capable of rapidly testing suspected chemicals, or tracking the development of a medical condition throughout a large population.
The development of novel sensing systems is completed with two separate goals. One is loop-mediated isothermal amplification based disease detection, and the other is thin layer chromatography based counterfeit medication analysis. In the biosensing approach, not only do the system detect viruses like zika, dengue, and chikungunya that cause human infectious diseases, but it diagnoses equine pathogens such as Streptococcus Zooepidemicus, Streptococcus Equi, and equine herpesviruses. Three different medications—paracetamol, nevirapine, and amodiaquine—are tested, and the counterfeit is distinguished from the genuine in chemical analysis. The systems consist of a smartphone with a customized application software, a cradle that supports internal electromechanical devices, and a microfluidic chip/plate where the assay occurs. Assay results from the inexpensive and handheld sensor instrument are comparable to those from conventional laboratory equipment, and the demonstration shows the potential utility of the newly developed system for the applications of POCD.
The ideal highly sensitive, inexpensive, and portable sensor is achieved using a mobile phone for bio/chemical applications. The exceptional computational and imaging capabilities of current smartphones enable their use as a convenient platform to perform assays and minimize cost and system complexity. The system could open a new era of fast, affordable, and accurate biomolecular and chemical diagnosis. With further customization specific to the diseases and medications, it would be utilized as a promising diagnostic tool to accomplish the POCD in low-income and resource-limited regions.