Lensfree super-resolution holographic microscopy using wetting films on a chip.

We investigate the use of wetting films to significantly improve the imaging performance of lensfree pixel super-resolution on-chip microscopy, achieving < 1 µm spatial resolution over a large imaging area of ~24 mm(2). Formation of an ultra-thin wetting film over the specimen effectively creates a micro-lens effect over each object, which significantly improves the signal-to-noise-ratio and therefore the resolution of our lensfree images. We validate the performance of this approach through lensfree on-chip imaging of various objects having fine morphological features (with dimensions of e.g., ≤0.5 µm) such as Escherichia coli (E. coli), human sperm, Giardia lamblia trophozoites, polystyrene micro beads as well as red blood cells. These results are especially important for the development of highly sensitive field-portable microscopic analysis tools for resource limited settings

Automated single-cell motility analysis on a chip using lensfree microscopy.

Quantitative cell motility studies are necessary for understanding biophysical processes, developing models for cell locomotion and for drug discovery. Such studies are typically performed by controlling environmental conditions around a lens-based microscope, requiring costly instruments while still remaining limited in field-of-view. Here we present a compact cell monitoring platform utilizing a wide-field (24 mm(2)) lensless holographic microscope that enables automated single-cell tracking of large populations that is compatible with a standard laboratory incubator. We used this platform to track NIH 3T3 cells on polyacrylamide gels over 20 hrs. We report that, over an order of magnitude of stiffness values, collagen IV surfaces lead to enhanced motility compared to fibronectin, in agreement with biological uses of these structural proteins. The increased throughput associated with lensfree on-chip imaging enables higher statistical significance in observed cell behavior and may facilitate rapid screening of drugs and genes that affect cell motility

Lensfree computational microscopy tools for cell and tissue imaging at the point-of-care and in low-resource settings.

The recent revolution in digital technologies and information processing methods present important opportunities to transform the way optical imaging is performed, particularly toward improving the throughput of microscopes while at the same time reducing their relative cost and complexity. Lensfree computational microscopy is rapidly emerging toward this end, and by discarding lenses and other bulky optical components of conventional imaging systems, and relying on digital computation instead, it can achieve both reflection and transmission mode microscopy over a large field-of-view within compact, cost-effective and mechanically robust architectures. Such high throughput and miniaturized imaging devices can provide a complementary toolset for telemedicine applications and point-of-care diagnostics by facilitating complex and critical tasks such as cytometry and microscopic analysis of e.g., blood smears, Pap tests and tissue samples. In this article, the basics of these lensfree microscopy modalities will be reviewed, and their clinically relevant applications will be discussed

Le juge administratif dans l'analyse juridique des politiques publiques

Aquesta ponència forma part del Workshop internacional de doctorands organitzat pel Programa de Doctorat en Dret de la UAB i la Facultat de Dret de la UAB, amb el suport de l'École Européenne de Droit de l'Université Toulouse Capitol

Lensfree Holographic Microscopy and Wide-field Optical Imaging using Wetting Films and Nano-Lenses

Impressive revolution of optical imaging and microscopy architectures has been expanding our horizon and increasing the opportunities in medical diagnostics. Although we experience significant advancements such as better resolution, speed and throughput, advanced imaging platforms are still complex, bulky and expensive, such that their function beyond well-established clinical environment is quite limited. Therefore, innovative imaging techniques are necessary to combat global health problems in resource-scarce settings where health care infrastructure is extremely limited or does not even exist. In such poor settings, imaging devices should be compact, robust, cost-effective and easy to use, without a trade-off in their performance.Centered on this vision, here I demonstrate a new lensfree on-chip microscopy and nano-particle imaging platform based on partially-coherent digital in-line holography, providing a highly-sensitive and high-throughput approach for rapid medical diagnostics and screening, especially for field settings and resource-limited environments. This computational microscopy and nano-particle imaging platform achieves subcellular spatial resolution and also directly images, for the first time in on-chip microscopy, single sub-100 nm particles using self-assembled aspheric liquid nano-lenses around individual nano-particles across a large field-of-view of >20 mm2, i.e., more than two orders-of-magnitude larger than existing nano-imaging techniques.This platform does not utilize any lenses, lasers or other bulky optical/mechanical components which greatly simplifies its architecture making it portable, light-weight, and cost-effective. It has been successfully implemented on a compact stand-alone unit which weighs only ~46 grams with dimensions smaller than 4.2 x 4.2 x 5.8 cm as well as on a commercially-available cell-phone that is modified with a light-weight (~ 38 grams) hardware attachment.Using stable and biocompatible wetting films to self-assemble aspheric liquid nano-lenses around individual nano-particles, I also introduce a wide-field on-chip microscopy modality that is capable of directly imaging single nano-particles and viruses (i.e., adenoviruses and influenza A (H1N1) viral particles) within a field-portable design.Creating new opportunities for rapid medical diagnostics in point-of-care and field conditions, this lensfree microscopy and nano-particle imaging toolset may bring improved healthcare delivery especially to resource-poor regions of the world and may significantly benefit our fight against various global health challenges including HIV, malaria, waterborne diseases and viral infections

Lensfree super-resolution holographic microscopy using wetting films on a chip.

We investigate the use of wetting films to significantly improve the imaging performance of lensfree pixel super-resolution on-chip microscopy, achieving < 1 µm spatial resolution over a large imaging area of ~24 mm(2). Formation of an ultra-thin wetting film over the specimen effectively creates a micro-lens effect over each object, which significantly improves the signal-to-noise-ratio and therefore the resolution of our lensfree images. We validate the performance of this approach through lensfree on-chip imaging of various objects having fine morphological features (with dimensions of e.g., ≤0.5 µm) such as Escherichia coli (E. coli), human sperm, Giardia lamblia trophozoites, polystyrene micro beads as well as red blood cells. These results are especially important for the development of highly sensitive field-portable microscopic analysis tools for resource limited settings

Cellphone-based devices for bioanalytical sciences

During the last decade, there has been a rapidly growing trend toward the use of cellphone-based devices (CBDs) in bioanalytical sciences. For example, they have been used for digital microscopy, cytometry, read-out of immunoassays and lateral flow tests, electrochemical and surface plasmon resonance based bio-sensing, colorimetric detection and healthcare monitoring, among others. Cellphone can be considered as one of the most prospective devices for the development of next-generation point-of-care (POC) diagnostics platforms, enabling mobile healthcare delivery and personalized medicine. With more than 6.5 billion cellphone subscribers worldwide and approximately 1.6 billion new devices being sold each year, cellphone technology is also creating new business and research opportunities. Many cellphone-based devices, such as those targeted for diabetic management, weight management, monitoring of blood pressure and pulse rate, have already become commercially-available in recent years. In addition to such monitoring platforms, several other CBDs are also being introduced, targeting e.g., microscopic imaging and sensing applications for medical diagnostics using novel computational algorithms and components already embedded on cellphones. This report aims to review these recent developments in CBDs for bioanalytical sciences along with some of the challenges involved and the future opportunities