Uzair Sikora

Integrated rapid-diagnostic-test reader platform on a cellphone

We demonstrate a cellphone-based rapid-diagnostic-test (RDT) reader platform that can work with various lateral flow immuno-chromatographic assays and similar tests to sense the presence of a target analyte in a sample. This compact and cost-effective digital RDT reader, weighing only ~65 g, mechanically attaches to the existing camera unit of a cellphone, where various types of RDTs can be inserted to be imaged in reflection or transmission modes under light-emitting diode (LED)-based illumination. Captured raw images of these tests are then digitally processed (within less than 0.2 s per image) through a smart application running on the cellphone for validation of the RDT, as well as for automated reading of its diagnostic result. The same smart application then transmits the resulting data, together with the RDT images and other related information (e.g., demographic data), to a central server, which presents the diagnostic results on a world map through geo-tagging. This dynamic spatio-temporal map of various RDT results can then be viewed and shared using internet browsers or through the same cellphone application. We tested this platform using malaria, tuberculosis (TB) and HIV RDTs by installing it on both Android-based smartphones and an iPhone. Providing real-time spatio-temporal statistics for the prevalence of various infectious diseases, this smart RDT reader platform running on cellphones might assist healthcare professionals and policymakers to track emerging epidemics worldwide and help epidemic preparedness.

Holographic pixel super-resolution in portable lensless on-chip microscopy using a fiber-optic array

We report a portable lensless on-chip microscope that can achieve <1 µm resolution over a wide field-of-view of ∼ 24 mm(2) without the use of any mechanical scanning. This compact on-chip microscope weighs ∼ 95 g and is based on partially coherent digital in-line holography. Multiple fiber-optic waveguides are butt-coupled to light emitting diodes, which are controlled by a low-cost micro-controller to sequentially illuminate the sample. The resulting lensfree holograms are then captured by a digital sensor-array and are rapidly processed using a pixel super-resolution algorithm to generate much higher resolution holographic images (both phase and amplitude) of the objects. This wide-field and high-resolution on-chip microscope, being compact and light-weight, would be important for global health problems such as diagnosis of infectious diseases in remote locations. Toward this end, we validate the performance of this field-portable microscope by imaging human malaria parasites (Plasmodium falciparum) in thin blood smears. Our results constitute the first-time that a lensfree on-chip microscope has successfully imaged malaria parasites.

Distributed medical image analysis and diagnosis through crowd-sourced games: a malaria case study.

In this work we investigate whether the innate visual recognition and learning capabilities of untrained humans can be used in conducting reliable microscopic analysis of biomedical samples toward diagnosis. For this purpose, we designed entertaining digital games that are interfaced with artificial learning and processing back-ends to demonstrate that in the case of binary medical diagnostics decisions (e.g., infected vs. uninfected), with the use of crowd-sourced games it is possible to approach the accuracy of medical experts in making such diagnoses. Specifically, using non-expert gamers we report diagnosis of malaria infected red blood cells with an accuracy that is within 1.25% of the diagnostics decisions made by a trained medical professional.

Lensfree On-Chip Microscopy and Tomography for Biomedical Applications

Lensfree on-chip holographic microscopy is an emerging technique that offers imaging of biological specimens over a large field-of-view without using any lenses or bulky optical components. Lending itself to a compact, cost-effective, and mechanically robust architecture, lensfree on-chip holographic microscopy can offer an alternative toolset addressing some of the emerging needs of microscopic analysis and diagnostics in low-resource settings, especially for telemedicine applications. In this study, we summarize the latest achievements in lensfree optical microscopy based on partially coherent on-chip holography, including portable telemedicine microscopy, cell-phone-based microscopy, and field-portable optical tomographic microscopy. We also discuss some of the future directions for telemedicine microscopy and its prospects to help combat various global health challenges.

Spectral Demultiplexing in Holographic and Fluorescent On-chip Microscopy

Lensfree on-chip imaging and sensing platforms provide compact and cost-effective designs for various telemedicine and lab-on-a-chip applications. In this work, we demonstrate computational solutions for some of the challenges associated with (i) the use of broadband, partially-coherent illumination sources for on-chip holographic imaging, and (ii) multicolor detection for lensfree fluorescent on-chip microscopy. Specifically, we introduce spectral demultiplexing approaches that aim to digitally narrow the spectral content of broadband illumination sources (such as wide-band light emitting diodes or even sunlight) to improve spatial resolution in holographic on-chip microscopy. We also demonstrate the application of such spectral demultiplexing approaches for wide-field imaging of multicolor fluorescent objects on a chip. These computational approaches can be used to replace e.g., thin-film interference filters, gratings or other optical components used for spectral multiplexing/demultiplexing, which can form a desirable solution for cost-effective and compact wide-field microscopy and sensing needs on a chip.

Smart rapid diagnostics test reader running on a cell-phone for real-time mapping of epidemics

Rapid diagnostics tests (e.g., immuno-chromatographic assays and other lateral-flow tests) offer significant advantages over conventional approaches (i.e., clinical examination and advanced medical tests) for the surveillance of infectious diseases especially in the remote parts of the world. In order to provide an integrated platform for automated digital reading and real-time mapping of rapid diagnostics tests (RDTs), we developed a universal RDT reader running on a cell-phone that can automatically digitize and evaluate various diagnostics test results. A custom-developed cell-phone application automatically processes raw transmission and reflection RDT images that are digitally acquired using a compact and cost-effective hardware attachment to generate semi-quantitative test evaluation reports. The same cell-phone application also connects this RDT reader to a central database/server that stores and displays RDT evaluation reports, mapping infectious diseases in real-time. Powered by the cell-phone battery or two AAA batteries, RDT reader attachment utilizes simple off-the-shelf components (e.g., multiple diffused light-emitting diode (LED) arrays and a plano-convex lens) and can be customized to fit on different cell-phone devices (i.e., iPhone and Android phones) without any major changes on its design. Providing spatio-temporal statistics for the prevalence of various infectious diseases, this integrated RDT reader platform can be especially useful to support epidemiological studies to fight against global health related problems. Here, we review our recent progress on this cellphone based RDT reader platform and discuss its potential use toward real-time mapping of various diseases globally.

Handheld, lensless microscope identifies malaria parasites

Optical microscopy is an indispensable tool in science and medicine. However, the size and cost of conventional optical microscopes limit their use in rugged field-settings or in remote areas to assist in tasks such as medical tests, disease diagnostics, or monitoring of water quality. In recent years, there has been widespread interest in reducing the size and cost of microscopes and making them more suited for point-of-care and telemedicine applications, or for tackling global health problems. These approaches range from miniaturizing traditional microscope designs and attaching them to cell phones, to eliminate lenses altogether

Field-Portable Lensless Holographic Microscope using Pixel Super-Resolution

We report a portable lensless holographic microscope utilizing pixel super-resolution to achieve <1um resolution and 24mm2 field-of-view. The performance of this light-weight (95g) microscope is validated by imaging malaria parasites in blood-smears.

Field-Portable Pixel Super-Resolution Microscopy of Dense Samples using Lensfree Holograms Recorded at Multiple Heights

By capturing lensfree in-line holograms of objects at multiple heights, phase and amplitude images of dense specimens (e.g. Papanicolaou smears) can be iteratively reconstructed over a large field-of-view (~30 mm2) with sub-micron resolution.

Portable and cost-effective pixel super-resolution on-chip microscope for telemedicine applications

We report a field-portable lensless on-chip microscope with a lateral resolution of <1μm and a large field-of-view of ∼24mm2. This microscope is based on digital in-line holography and a pixel super-resolution algorithm to process multiple lensfree holograms and obtain a single high-resolution hologram. In its compact and cost-effective design, we utilize 23 light emitting diodes butt-coupled to 23 multi-mode optical fibers, and a simple optical filter, with no moving parts. Weighing only ∼95 grams, we demonstrate the performance of this field-portable microscope by imaging various objects including human malaria parasites in thin blood smears.