A low cost, safe, disposable, rapid and self-sustainable paper-based platform for diagnostic testing: lab-on-paper

Abstract

There is a strong interest in the use of biopolymers in the electronic and biomedical industries, mainly towards low-cost applications. The possibility of developing entirely new kinds of products based on cellulose is of current interest, in order to enhance and to add new functionalities to conventional paper-based products. We present our results towards the development of paper-based microfluidics for molecular diagnostic testing. Paper properties were evaluated and compared to nitrocellulose, the most commonly used material in lateral flow and other rapid tests. Focusing on the use of paper as a substrate for microfluidic applications, through an eco-friendly wax-printing technology, we present three main and distinct colorimetric approaches: (i) enzymatic reactions (glucose detection); (ii) immunoassays (antibodies anti-Leishmania detection); (iii) nucleic acid sequence identification (Mycobacterium tuberculosis complex detection). Colorimetric glucose quantification was achieved through enzymatic reactions performed within specific zones of the paper-based device. The colouration achieved increased with growing glucose concentration and was highly homogeneous, covering all the surface of the paper reaction zones in a 3D sensor format. These devices showed a major advantage when compared to the 2D lateral flow glucose sensors, where some carryover of the coloured products usually occurs. The detection of anti-Leishmania antibodies in canine sera was conceptually achieved using a paper-based 96-well enzyme-linked immunosorbent assay format. However, optimization is still needed for this test, regarding the efficiency of the immobilization of antigens on the cellulose fibres. The detection of Mycobacterium tuberculosis nucleic acids integrated with a non-cross-linking gold nanoprobe detection scheme was also achieved in a wax-printed 384-well paper-based microplate, by the hybridization with a species-specific probe. The obtained results with the above-mentioned proof-of-concept sensors are thus promising towards the future development of simple and cost-effective paper-based diagnostic devices.

Performance of solid and liquid culture media for the detection of Mycobacterium tuberculosis in clinical materials: meta-analysis of recent studies

“…In conclusion, culture remains the key technology in the diagnosis of TB, despite emerging new technologies, including polymerase chain reaction (PCR) or other methods [7,8]. However, also, culture needs to be subjected to thorough quality assessment locally, given the large differences in time to positivity that can be distilled from the international literature, even when a well-accepted culture medium such as LJ is being considered.…”

Achieving Enzyme Stability Using a Simple Fabrication Procedure: The Alcohol Dehydrogenase Example

“…Paper is an environmental friend material, easily manipulated, cheap, and biocompatible; has high adaptability for analysis of different substances. These properties make paper the perfect physic base for introducing microfluidic channels and to be used in Point-of-care devices [5,[8][9][10]. One disadvantage of The use of disposable and miniaturized biosensors that can detect subtract, like glucose and ethanol, in biological fluid or in food, with accuracy has been developed since the nineties [1][2][3][4][5].…”

Desenvolvimento de um teste rápido microfluídico para detecção de sulfonamidas em leite a partir de ensaios colorimétricos

“…Química de superfície e porosidade influenciam na imobilização de biomoléculas, como anticorpos e oligonucleotídeos, bem como na absorção do fluido [18,19]. O conhecimento das propriedades ópticas do papel também é importante, pois pode influenciar nos resultados dos testes visuais ou com detecção óptica [18].…”

“…Área cristalina e biológicos, ela não se apresenta como matriz ideal para dispositivos de fluxo lateral, pois possui características como elevada capacidade de se ligar a proteínas, além de ser altamente inflamável e apresentar baixas propriedades mecânicas [18,36]. O papel a base de celulose não apresenta tais desvantagens e possui as propriedades ideais para o desenvolvimento de plataformas de diagnóstico colorimétrico [18].…”

“…O papel a base de celulose não apresenta tais desvantagens e possui as propriedades ideais para o desenvolvimento de plataformas de diagnóstico colorimétrico [18].…”