Bio-inspired surfaces with superamphiphobic properties are well known as effective candidates for antifouling technology. However, the limitation of large-area mastering, patterning and pattern collapsing upon physical contact are the bottleneck for practical utilization in marine and medical applications. In this study, a roll-to-plate nanoimprint lithography (R2P NIL) process using Morphotonics’ automated Portis NIL600 tool was used to replicate high aspect ratio (5.0) micro-structures via reusable intermediate flexible stamps that were fabricated from silicon master molds. Two types of Morphotonics’ in-house UV-curable resins were used to replicate a micro-pillar (PIL) and circular rings with eight stripe supporters (C-RESS) micro-structure onto polycarbonate (PC) and polyethylene terephthalate (PET) foil substrates. The pattern quality and surface wettability was compared to a conventional polydimethylsiloxane (PDMS) soft lithography process. It was found that the heights of the R2P NIL replicated PIL and C-RESS patterns deviated less than 6% and 5% from the pattern design, respectively. Moreover, the surface wettability of the imprinted PIL and C-RESS patterns was found to be superhydro- and oleophobic and hydro- and oleophobic, respectively, with good robustness for the C-RESS micro-structure. Therefore, the R2P NIL process is expected to be a promising method to fabricate robust C-RESS micro-structures for large-scale anti-biofouling application.

The diagnosis of filariasis traditionally relies on the detection of circulating microfilariae (mf) using Giemsa-stained thick blood smears. This approach has several limitations. We developed a semi-automated microfluidic device to improve and simplify the detection of filarial nematodes. The efficiency and repeatability of the microfluidic device was evaluated. Human EDTA blood samples were ‘spiked’ with B. malayi mf at high, moderate, and low levels, and subsequently tested 10 times. The device was also used for a field survey of feline filariasis in 383 domesticated cats in an area of Narathiwat Province, Thailand, the endemic area of Brugia malayi infection. In the control blood arbitrarily spiked with mf, the high level, moderate level and low level mf-positive controls yielded coefficient variation (CV) values of 4.44, 4.16 and 4.66%, respectively, at the optimized flow rate of 6 µl/min. During the field survey of feline filariasis in Narathiwat Province, the device detected mf in the blood of 34 of 383 cats (8.9%) whereas mf were detected in 28 (7.3%) cats using the blood smear test. Genomic DNA was extracted from mf trapped in the device after which high-resolution melting (HRM) real-time PCR assay was carried out, which enabled the simultaneous diagnosis of filarial species. Among the 34 mf-positive samples, 12 were identified as B. malayi, 15 as Dirofilaria immitis and 7 as| D. repens. We developed a semi-automated microfluidic device to detect mf of filarial parasites that could be used to diagnose lymphatic filariasis in human populations. This novel device facilitates rapid, higher-throughput detection and identification of infection with filariae in blood samples.

Lymphatic filariasis (LF) is a neglected major tropical disease that is a leading cause of permanent and long-term disability worldwide. Significant progress made by the Global Programme to Eliminate Lymphatic Filariasis (GPELF) has led to a substantial decrease in the levels of infection. In this limitation, DNA detection of lymphatic filariae could be useful due to it capable of detecting low level of the parasites. In the present study, we developed a diagnostic assay that combines a miniPCR with a duplex lateral flow dipstick (DLFD). The PCR primers were designed based on the HhaI and SspI repetitive noncoding DNA sequences of Brugia malayi and Wuchereria bancrofti, respectively. The limits of detection and crossreactivity of the assay were evaluated. In addition, blood samples were provided by Thais living in a brugian filariasis endemic area. The miniPCR-DLFD assay exhibited a detection limit of 2 and 4 mf per milliliter (mL) of blood for B. malayi as well as W. bancrofti, respectively, and crossamplification was not observed with 11 other parasites. The result obtained from the present study was in accordance with the thick blood smear staining for the known cases. Thus, a miniPCR-DLFD is an alternative tool for the diagnosis of LF in point-of-collection settings with a modest cost (~USD 5) per sample.

The objective of this research work is to propose a phase diagram that can be used to find a proper operating condition for generating droplets of different types. It is found that the phase diagram of Q_R versus Ca_D can effectively classify the droplet generation into three vivid regimes: dripping, jetting and tubing. For the dripping regime, its operating condition is in the range of either Ca_D < 10⁻⁴ and Q_R < 50 or 10⁻³ < Ca_D < 10⁻⁴ and Q_R < 1. For the jetting regime, its operating condition is in the range of either Ca_D < 1.35 × 10⁻² and Q_R > 100 or Ca_D > 1.35 × 10⁻² and Q_R > 1. For the tubing regime, its operating condition is in the range of Ca_D > 1.35 × 10⁻² and Q_R < 1.

Lymphatic filariasis (LF) is a leading cause of permanent disability worldwide that has been listed as a neglected tropical disease by the World Health Organization. Significant progress made by the Global Program to Eliminate Lymphatic Filariasis (GPELF) has led to a substantial decline in the population of the worm that causes LF infection. Diagnostic assays capable of detecting low levels of parasite presence are needed to diagnose LF. There is also a need for new tools that can be used in areas where multiple filarial species are coendemic and for mass screening or for use in a point-of-care setting. In the present study, we applied our previously developed semi-automated microfluidic device in combination with our recently developed mini polymerase chain reaction (miniPCR) with a duplex lateral flow dipstick (DLFD) (miniPCR-DLFD) for rapid mass screening and visual species identification of lymphatic filariae in human blood. The study samples comprised 20 Brugia malayi microfilariae (mf) positive human blood samples, 14 Wuchereria bancrofti mf positive human blood samples and 100 mf negative human blood samples. Microfilariae detection and visual species identification was performed using the microfluidic device. To identify the species of the mf trapped in the microfluidic chips, DNA of the trapped mf was extracted for miniPCR amplification of W. bancrofti and B. malayi DNA followed by DLFD. Thick blood smear staining for microfilariae detection was used as the gold standard technique. Microfilariae screening and visual species identification using our microfluidic device plus miniPCR-DLFD platform yielded results concordant with those of the gold standard thick blood smear technique. The microfluidic device, the miniPCR and the DLFD are all portable and do not require additional equipment. Use of this screening and visual species identification platform will facilitate reliable, cost-effective, and rapid surveillance for the presence of LF infection in resource-poor settings.

Dynamic gut-on-a-chip platform allows better recreation of the intestinal environment in vitro compared to the traditional static cell culture. However, the underlying mechanism is still not fully discovered. In this study, the shear stress behavior in a gut-on-a-chip device with porous membrane subjected to peristalsis motion is numerically investigated using CFD simulation for three different pore sizes and two pattern layouts. The results reveal that, in the stationary microchannel, the average shear stress on the porous membrane is approximately 15% greater than that of the flat membrane, regardless of the pore size. However, when subjected to cyclic deformation, the porous membrane with smaller pore size experiences stronger variation of shear stress which is ±5.61%, ±10.12% and ±34.45% from its average for the pore diameters of 10 μm, 5 μm and 1 μm, respectively. The shear stress distribution is more consistent in case of the staggered pattern layout while the in-line pattern layout allows for a 32% wider range of shear stress at the identical pore size during a cyclic deformation. These changes in the shear stress caused by peristalsis motion, porous size and membrane pattern could be the key factors that promote cell differentiation in the deforming gut-on-a-chip model.