Recently, ultrasonic molding (USM) has emerged as a promising replication technique for low and medium volume production of miniature and micro-scale parts. In a relatively short time cycle, ultrasonic molding can process a wide variety of polymeric materials without any noticeable thermal degradation into cost-effective molded parts. This research work reviews recent breakthroughs of the ultrasonic injection molding and ultrasonic compression molding process regarding the equipment and tooling development, materials processing and potential applications in the medical industry. The discussion is centered on the challenges of industrializing this technology, pointing out the need for improvement of the current process’s robustness and repeatability. Among the most important research areas that were identified are the processing of novel engineered and nanomaterials, the understanding and control of the ultrasonic plasticization process and the tooling and equipment development.
During
the γ-radiation sterilization process, the levels
of radiation exposure to a medical device must be carefully monitored
to achieve the required sterilization without causing deleterious
effects on its intended physical and chemical properties. To address
this issue, here we have demonstrated the development of an all-printed
disposable low-cost sensor that exploits the change in electrical
impedance of a semi-interpenetrating polymer network (SIPN) composed
of poly(vinyl alcohol) (PVA) and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate
(PEDOT:PSS) as a functional polymer composite for radiation sterilization
monitoring applications. Specifically, the PEDOT:PSS acts as the electrically
conductive medium, while the PVA provides the ductility and stability
of the printed sensors. During irradiation exposure, chain scission
and cross-linking events occur concurrently in the PEDOT:PSS and PVA
polymer chains, respectively. The concurrent scissoring of the PEDOT
polymer and cross-linking of the PVA polymer network leads to the
formation of a stable SIPN with reduced electrical conductivity, which
was verified through FTIR, Raman, and TGA analysis. Systematic studies
of different ratios of PEDOT:PSS and PVA mixtures were tested to identify
the optimal ratio that provided the highest radiation sensitivity
and stability performance. The results showed that PEDOT:PSS/PVA composites
with 10 wt % PVA produced sensors with relative impedance changes
of 30% after 25 kGy and up to 370% after 53 kGy (which are two of
the most commonly used radiation exposure levels for sterilization
applications). This composition showed high electrical impedance stability
with less than ±5% change over 18 days after irradiation exposure.
These findings demonstrate the feasibility of utilizing a printing
technology for scalable manufacturing of low-cost, flexible radiation
sensors for more effective monitoring of radiation sterilization processes.
Many
commercially available pH sensors are fabricated with a glass
membrane as the sensing component because of several advantages of
glass-based electrodes such as versatility, high accuracy, and excellent
stability in various conditions. However, because of their bulkiness
and poor mechanical properties, conventional glass-based sensors are
not ideal for wearable or flexible applications. Here, we report for
the first time the fabrication of a flexible glass-based pH sensor
suitable for biomedical and environmental applications where flexibility
and stability of the sensor are critical for long-term and real-time
monitoring. The sensor was fabricated via a simple and facile approach
using the cold atmospheric plasma technique in which a pH sensitive
silica coating was deposited from a siloxane precursor onto a carbon
electrode. In order to increase the sensitivity and stability of the
sensor, we employed a postprocessing step which involves annealing
of the silica coated electrode at elevated temperatures. This process
was optimized to ensure that the crucial properties such as porosity
and hydration functionality were balanced to obtain the best and most
reliable sensitivity of the sensor. Our sensitivity test results indicated
that these sensors exhibit excellent and stable sensitivity with a
slope of about 48 mV/pH (r
2 = 0.998) and
selectivity across a pH range of 4 to 10 in the presence of various
cations. The optimized sensor has shown stable sensitivity for a long
period of time (30 h of immersion) and in different bending conditions.
We demonstrate in this investigation that this flexible cost-effective
pH sensor can withstand the sterilization process resulting from ultraviolet
radiation and shows repeatable sensitivity with less than ±5
mV potential drift from the sensitivity values of the standard optimized
sensor.
A non-invasive sampling capsule is introduced to site-selectively collect calprotectin biomarker from the small intestine. This approach can be accompanied with the fecal calprotectin assay to diagnose IBD and differentiate its types (CD and UC).
Gamma radiation sterilization approach has been widely used for pharmaceutical packaging worldwide. Therefore, the development of an advanced dosimeter for monitoring the gamma radiation dosage during the sterilization process is...
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