Recently, lens-free imaging has evolved as an alternative imaging technology. The key advantages of this technology, including simplicity, compactness, low cost, and flexibility of integration with other components, have facilitated the realization of many innovative applications, especially, in the fields of the on-chip lens-free imaging and sensing. In this talk, we present a brief review about the theory and the development of a low-cost lens-free imaging system as part of the scientific project of multidisciplinary collaboration between physicians, opticians, engineers and biomedical scientists from four different countries from South-America and France, and an industrial company. Lens-free (or lens-less) imaging is emerging as a cost-effective, compact, and light-weight detection method that can serve numerous biological applications. Our ai mis to provide a field-portable platform, which is ideal for affordable point-of-care devices aiming at resource-limited settings, for the detection of two different study cases, the first one: Mycobacterium Tuberculosis in Peru, Ecuador and Bolivia; and the second one: Trypanosoma Cruzis mainly in Bolivia and Peru. Since last year, we are working on the conception, design and implementation of new optical setups and the implementation of standard algorithms for the reconstruction of objects using numerical holograms and shadow images. A recent project has been submitted for the program ERANet-LAC, with the aim to expand and to develop other optical techniques such as fluorescence microscopy with tuneable liquid lenses. We have also a new set-up in progress for the surface plasmon resonance imaging for the detection of virus like particle, oriented to the rapid detection of Norovirus, which is nowadays considered a big challenge around the world.