Medical devices & sensors最新文献

The cover image is based on the Original Article UV-Induced DNA Damage Response in Blood Cells for Cancer Detection by Fariborz Taghipour et al., https://doi.org/10.1002/mds3.10146. We are grateful to Sonia H.Y. Kung for designing the cover art.

The biotechnology sector needs cost-effective, renewable, reusable and sustainable raw materials. There are many different biomaterials existed in this area, such as magnetic nanoparticles, silica, clay and polymers. But they have many disadvantages about cost, preparation conditions and toxic chemicals. Aerogel technology provides high added-value lightweight materials with huge porous structures high surface area and low density. The aerogels are classified into inorganic and organic according to the source of gel precursors. The inorganic aerogels are mostly prepared from alkoxides and various metal oxides. But either inorganic aerogels or first organic aerogels (resorcinol–formaldehyde) are composed of toxic chemicals that inherent them using in life science. Nowadays for preparing organic aerogels, natural precursors, such as polysaccharides (cellulose, chitosan, starch, alginate, carrageenan and curdlan) or proteins (silk fibroin and ovalbumin), milk (caseins and whey proteins, soy), are used and named as bioaerogels or biobased aerogels. All of these components are natural, biodegradable, bioactive and biocompatible for human. The biobased aerogels are mostly synthesized with polysaccharides. The natural polysaccharides and/or their derivatives can be used because of their availability, low toxicity, stability upon storage, good biological performance and enzyme-controlled biodegradability. Also, cellulose-based aerogels can be prepared using many renewable sources (wheat husk, potato tubers, paper waste, bagasse, etc) which is also very important for waste management. Biodegradable and biobased aerogels are of increasing pursuit, as the use of these compounds can be an alternative for reducing the impact on the environment. This mini review summarized the steps of preparation techniques of aerogels and explained the usage areas of biobased aerogels with examples of in drug delivery, wound healing and tissue engineering.

Magnesium (Mg) alloys show promise in biomedical implants due to their excellent mechanical strength, biocompatibility and biodegradability. However, their rapid degradation rates in vivo induce toxicity and reduce their mechanical strength thereby, limiting their widespread usage. Our group employs a 3D inkjet printing technique for polymeric surface modification of bioresorbable AZ31 Mg alloy towards corrosion control. Thin films of three proprietary formulations of elastomeric poly (ester urethane) urea (PEUU) embedded with an anti-proliferative drug paclitaxel (Taxol) were coated on biodegradable AZ31 Mg coupons. Multilayer coatings of 5 and 20 layers were deposited for virgin (PEUU-V), PEUU with phosphorylcholine (PEUU-PC) and PEUU with sulfobetaine (PEUU-SB). Coating thicknesses of 8 µm and 19 µm were observed for 5-layer and 20-layer coatings, respectively. Surface morphology results depicted the presence of Taxol beads on PEUU-V and PEUU-SB coatings due to precipitation. An equivalent circuit model was used to calculate the polarization resistance values and revealed that the polymeric coatings provided a significant protective effect on the corrosion rate of AZ31 Mg alloy. Electrochemical impedance spectroscopy measurements indicated that PEUU-SB offered the least resistance to corrosion and had the highest porosity (35.6%) among all the polymeric coatings. PEEU-V polymeric coatings offered the greatest polarization resistance with the least porosity (10.5%). Statistical analysis confirmed that the 20-layer coating thickness had a significantly higher polarization resistance than the 5-layer coatings. This research lays the foundation for developing corrosion control drug-eluting coatings for cardiovascular and other medical device applications via surface modification using 3D inkjet printing.

Significant advances have been presented in the last decades in the field of biomedical analysis and sensing, especially pertaining to routine procedures based on immunologic and nucleic acids, including enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (RTq-PCR). Despite their efficiency, some limitations such as reagent stability and availability, cost and cumbersome analysis procedures still limit further advances in this area. In this context, the development of molecularly imprinted polymers (MIPs) for biomedical purposes has contributed to the improvement of consolidated applications and the development of new approaches in a wide range of application scenarios. This review discusses the contribution of MIPs for advances in biomedical sensing in the past 5 years highlighting their main synthesis strategies, and applications especially for the detection of biomarkers, viruses and bacteria. Last but not least, the utility of MIPs in diagnostic imaging is emphasized.

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the West and has a 5-year survival rate of only 2%–9%. Pancreatic cystic lesions are precursors of pancreatic cancers and a prime target for early diagnosis. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) enables collection of cystic fluid aiming for the diagnosis of malign and premalign cysts. However, this fluid is acellular or paucicellular in 20% of cases, hampering a proper diagnosis. Here, we introduce a minimally invasive Nitinol brush that can be operated through the 413 µm lumen of a 22G FNA needle. During operation, the brush is rotated against the inner wall of the cyst, removing cells and dispersing them in the cystic fluid, where they can be aspirated through the needle. We demonstrate the brush function using three models. An in vitro cyst model was used to visualize the brushing procedure and the mechanical interaction between the brush and the wall of a spherical cavity. Ex vivo porcine intestine and bovine ovary cyst models were used to demonstrate how brushing increases the number of harvested cells with more than one order of magnitude. These results indicate the potential of cystic brushing for the minimally invasive early diagnosis of pancreatic adenocarcinoma.

We present the conceptual design of a complete health suit. This suit is designed to provide clean, virus-free air to its wearer either from an oxygen cylinder or through an air purification system that consists of an ultraviolet lamp, or a soap solution-based air purifier. This health suit, if designed and fabricated properly, should help prevent the spread of COVID-19 and similar type other airborne virus infections in human beings.

Focused Ultrasound (FUS) continues to gain acceptance in the clinical realm for its ability to provide effective, non-invasive therapeutic treatments to almost any region of the body for a host of ablative and non-ablative applications. The development of FUS devices and their implementation requires reliable characterization and quality assurance methods to verify acoustic pressure fields and focal region characteristics. The use of hydrophones is a conventional technique for mapping the acoustic field in 3 dimensions to provide focal dimensions and location. Hydrophones, however, are expensive and may be damaged even at relatively low acoustic amplitudes. Data collection with these devices can also be labor intensive and difficult to accurately reproduce. We present preliminary findings for the development of an alternative characterization process for FUS transducers that is relatively inexpensive and time efficient. Thermochromic liquid crystal (TLC) film sensors exploit the thermochromic effect, in which exposure to specific temperature changes cause a visible change in colour. The method was tested on a portable FUS system developed in-house for FUS-based therapeutic applications, comprised of a 3.57 MHz FUS transducer, and a custom-fabricated coupling cone. The results demonstrated that this method using TLC films was able to accurately provide dimensions of the focal zone and its position relative to the transducer hardware. Numerical simulations were performed along with acoustic hydrophone measurements to corroborate this data, which were found to be in general agreement. With future refinements, this cost-effective method could be practical as an expedient and cost-effective characterization technique for in-house FUS transducer development.

The main clinical characteristics of COVID-19 are respiratory symptoms that can lead to serious cardiovascular damages and severe worsening of other medical conditions. One of the major strategies in preparedness and response to COVID 19 is effective utilization of personal protective equipment (PPE) among which the masks of different kinds are on the top of the list especially for activities in the public places. However, the underlying mechanisms of masks in preventing virus transmission have not been well identified and the current experimental data still show inconsistent outcomes that may mislead the public. For instance, the early understanding of the mask functions was limited especially in the escalating phase of the COVID 19 pandemic, resulting in quite controversial remarks on masks. Although extensive studies in mask functions have been carried out ever since the COVID-19 outbreaks, most of the investigations appear to have focused on exhalation isolation of individuals who may have been infected with the disease. Less emphasis was laid on inhalation protection from virus transmission, an important aspect that undergirds the public health policies and protective strategies. This review provides the most up-to-date information on the transmission modes of COVID-19 virus in terms of droplets and aerosols. The roles of masks in disease prevention and transmission reduction are evaluated on various types, structures and functions. More important, both aspects of exhalation isolation and inhalation protection are discussed based on virus transmission modes and the effectiveness of different types of masks under varied environmental conditions.

Exhaled breath test is a typical disease monitoring method for replacing blood and urine samples that may create discomfort for patients. To monitor exhaled breath markers, gas biomedical sensors have undergone rapid progress for non-invasive and point-of-care diagnostic devices. Among gas sensors, metal oxide-based biomedical gas sensors have received remarkable attention owing to their unique properties, such as high sensitivity, simple fabrication, miniaturization, portability and real-time monitoring. Herein, we reviewed the recent advances in chemoresistive metal oxide-based gas sensors with ZnO, SnO₂ and In₂O₃ as sensing materials for monitoring a range of exhaled breath markers (i.e., NO, H₂, H₂S, acetone, isoprene and formaldehyde). We focused on the strategies that improve the sensitivity and selectivity of metal oxide-based gas sensors. The challenges to fabricate a functional gas sensor with high sensing performance along with suggestions are outlined.

The biocompatibility of conducting polymer has seen remarkable advancement in numerous biomedical applications. The tuneable electrical property expressed by doping and de-doping of the polymer has contributed to electrical controlled film in terms of volume and conductivity. Also, higher sensitivity specially for ionic molecules brings forward new prospective in bio/sensing. Meanwhile, wearable devices for healthcare monitoring are becoming more prominent due to remote, real-time and continuous monitoring. The flexible and stretchable property of organic electronic, in this paper represented by conducting polymer, as compared to rigid, conventional conductor unleashes high potential of conducting polymer as platform for wearable sensing device. In this review, properties of conducting polymers adopted in wearable devices focusing on on-skin sensing are elaborated. The contribution of conducting polymers in various sensing targets, mainly categorized by chemical, tactile and electrophysiological is discussed, followed by types of the wearable sensors. Overall, our aim was to lay broader understanding of incorporation of the polymer within wearable sensing devices.