In this work, synergistic
effects derived from surface engineering
and dielectric property tuning were exploited to enhance the output
performance of a triboelectric nanogenerator (TENG) based on an inorganic/porous
PDMS composite in a contact–separation mode. BaTiO3 (BT)/porous PDMS films with different BT weight ratios were fabricated
and evaluated for triboelectric nanogenerator (TENG) application.
Maximum output signals of ca. 2500 V, 150 μA, and a power density
of 1.2 W m–2 are achieved from the TENG containing
7 wt % BT, which is the best compromise in terms of surface roughness,
dielectric constant, and surface contact area as evidenced by SEM
and AFM studies. These electrical signals are 2 times higher than
those observed for the TENG without BT. The 7BT/porous PDMS-based
TENG also shows high stability without a significant loss of output
voltage for at least 24 000 cycles. With this optimized TENG,
more than 350 LEDs are lit up and a wireless transmitter is operated
within 9 s. This work not only shows the promoting effects from porous
surfaces and an optimized dielectric constant but also offers a rapid
and template/waste-free fabrication process for porous PDMS composite
films toward large-scale production.
Background
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.
Methods
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.
Results
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
.
Conclusions
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.
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