Christopher Moraes

Have microfluidics delivered for drug discovery

The drug discovery process is usually initiated with a benchtop discovery in which cultured cells are observed to respond to a drug, which is then tested in animal and human clinical trials prior to bringing a product to market. Drug development expenses in the pharmaceutical industry have skyrocketed in recent years, while the number of truly innovative drugs approved by governmental regulatory bodies is decreasing [1]. Cell-based high-throughput screening (HTS) techniques have enabled researchers to screen over a million compounds in 1–3 months [2], but only 1 in every 5000 promising ‘hits’ successfully transitions from the benchtop to the market [3], as the vast majority of discoveries fail during animal testing and human clinical trials. This low success rate results in an average development time of 10–12 years, with an estimated average cost of

Nanodarts, nanoblades, and nanospikes: Mechano-bactericidal nanostructures and where to find them

2.6 billion to bring each drug to market [4], resulting in unsustainable costs to global health-care systems. Currently, automated HTS methods using robotic handling and analysis systems are the gold standard in drug discovery. The design requirements of these systems seem ideally suited toward applying novel microfluidic approaches to improve HTS. Microfluidics is an established strategy to reduce culture vessel sizes and precisely control fluid movement down to the picoliter range. Miniaturizing and integration of microfluidics with other complimentary microsystems would enable massive parallelization and highly combinatorial cell-based assays, reducing the overall cost of reagents, and improving assay reproducibility, speed, and experimental throughput [5]. These advances should have substantially reduced the cost of drug discovery, while enabling the unique discovery of new therapeutics that would not have been identified using conventional technologies. Yet, despite rapid development of expertise in designing, fabricating, and operating microfluidic systems over nearly two decades, to the best of our knowledge, no commercially available drugs have been discovered as a unique result of microfluidic technologies. While microfluidics has been adopted into liquid-handling systems that automate the screening process, the assays themselves are still conducted in multi-well plate dishes. The reasons for this are varied. Perhaps discoveries have been made, but are still in the drug development pipeline. More likely, however, is that although these systems are powerful in the lab, they require skilled operators and are not robust or scalable enough to handle the stringent demands for HTS of millions of compounds, while the existing multi-well plate technologies are more than adequate for these needs. Although several companies (BellBrooks, Dolomite, Caliper, and Nanoscale, among others) have developed high-throughput tools and robust fabrication methodologies to incorporate microfluidics into culture plates, we believe that the real power of microfluidic systems for drug discovery still remains to be realized. In this short opinion paper, we highlight three high-potential research areas for microengineered systems in drug discovery and recent articles that build toward better therapeutic discovery platforms. Specifically, we discuss how microengineered systems may be useful to probe functional activity of cells in HTS, develop more realistic environments within which to screen drugs, and build organ-on-a-chip constructs to prescreen candidate therapeutics. Cell-based assays have traditionally relied upon some identified biomarker that indicates how well the candidate therapeutic is performing. Although useful, it remains uncertain whether the selected readouts are sufficient to ensure that the treatment is holistically altering cell activity. Hence, analyses of functional cellular activity are now being considered as readouts that may have greater predictive potential, and microengineered systems are well suited to measure these activities. For example, microfluidic cytometers have been developed to identify potentially cancerous cells based on changes in the intrinsic stiffness of the cell, which presumably allows them to metastasize through tissue [6]. Cell-generated contractile forces may also signify functional activity tied to homeostasis or disease progression, and measuring these forces may provide an integrative picture of overall cell health. While several techniques exist to measure cellular forces [7–9], these have only recently been adapted for large-scale HTS drug screening by Park et al., who developed multi-well plates with integrated soft hydrogel culture surfaces labeled with fiduciary markers [10]. Contractile force was used to identify novel chemicals from existing libraries that reduced the forces generated by asthmatic airway smooth muscle cells. Several techniques exist to measure cellular forces [11], and so this

Microfluidics in microbiology: putting a magnifying glass on microbes

Over the past ten years, a next-generation approach to combat bacterial contamination has emerged: one which employs nanostructure geometry to deliver lethal mechanical forces causing bacterial cell death. In this review, we first discuss advances in both colloidal and topographical nanostructures shown to exhibit such mechano-bactericidal mechanisms of action. Next, we highlight work from pioneering research groups in this area of antibacterials. Finally, we provide suggestions for unexplored research topics that would benefit the field of mechano-bactericidal nanostructures. Traditionally, antibacterial materials are loaded with antibacterial agents with the expectation that these agents will be released in a timely fashion to reach their intended bacterial metabolic target at a sufficient concentration. Such antibacterial approaches, generally categorized as chemical-based, face design drawbacks as compounds diffuse in all directions, leach into the environment, and require replenishing. In contrast, due to their mechanisms of action, mechano-bactericidal nanostructures can benefit from sustainable opportunities. Namely, mechano-bactericidal efficacy needs not replenishing since they are not consumed metabolically, nor are they designed to release or leach compounds. For this same reason, however, their action is limited to the bacterial cells that have made direct contact with mechano-bactericidal nanostructures. As suspended colloids, mechano-bactericidal nanostructures such as carbon nanotubes and graphene nanosheets can pierce or slice bacterial membranes. Alternatively, surface topography such as mechano-bactericidal nanopillars and nanospikes can inflict critical membrane damage to microorganisms perched upon them, leading to subsequent cell lysis and death. Despite the infancy of this area of research, materials constructed from these nanostructures show remarkable antibacterial potential worthy of further investigation.

KIBRA (WWC1) Is a Metastasis Suppressor Gene Affected by Chromosome 5q Loss in Triple-Negative Breast Cancer

Microfluidic technologies enable unique studies in the field of microbiology to facilitate our understanding of microorganisms. Using miniaturized and high-throughput experimental capabilities in microfluidics, devices with controlled microenvironments can be created for microbial studies in research fields such as healthcare and green energy. In this research highlight, we describe recently developed tools for diagnostic assays, high-throughput mutant screening, and the study of human disease development as well as a future outlook on microbes for renewable energy.

Gotta catch ‘em all: the microscale quest to understand cancer biology

Summary Triple-negative breast cancers (TNBCs) display a complex spectrum of mutations and chromosomal aberrations. Chromosome 5q (5q) loss is detected in up to 70% of TNBCs, but little is known regarding the genetic drivers associated with this event. Here, we show somatic deletion of a region syntenic with human 5q33.2–35.3 in a mouse model of TNBC. Mechanistically, we identify KIBRA as a major factor contributing to the effects of 5q loss on tumor growth and metastatic progression. Re-expression of KIBRA impairs metastasis in vivo and inhibits tumorsphere formation by TNBC cells in vitro. KIBRA functions co-operatively with the protein tyrosine phosphatase PTPN14 to trigger mechanotransduction-regulated signals that inhibit the nuclear localization of oncogenic transcriptional co-activators YAP/TAZ. Our results argue that the selective advantage produced by 5q loss involves reduced dosage of KIBRA, promoting oncogenic functioning of YAP/TAZ in TNBC.

The Discovery Channel: microfluidics and microengineered systems in drug screening

Developing an improved understanding of the processes that drive cancer initiation and progression has been the focus of intense research in recent years. Here, we highlight recent advances in the innovative use of microscale engineered technologies to gain new insight into the integrative biophysical mechanisms that drive these processes.