Microneedles (MNs) are emerging as versatile tools for both therapeutic drug delivery and diagnostic monitoring. Unlike hypodermic needles, MNs achieve these applications with minimal or no pain and customizable designs, making them suitable for personalized medicine. Understanding the key design parameters and the challenges during contact with biofluids is crucial to optimizing their use across applications. This review summarizes the current fabrication techniques and design considerations tailored to meet the distinct requirements for drug delivery and biosensing applications. We further underscore the current state of theranostic MNs that integrate drug delivery and biosensing and propose future directions for advancing MNs toward clinical use.
Microneedles (MNs) or microneedle arrays (MNAs) are critical components of minimally invasive devices comprised of a single or a series of micro-scale projections. MNs can bypass the outermost layer of the skin and painlessly access microcirculation of the epidermis and dermis layers, attracting great interest in the development of personalized healthcare monitoring and diagnostic devices. However, MN technology has not yet reached its full potential since current micro- and nanofabrication methods do not address the need of fabricating MNs with complex surfaces to facilitate the development of clinically adequate devices. This work presents a new approach that combines 3D printing technology based on two-photon polymerization with soft lithography for cost-effective and time-saving fabrication of complex MNAs. Specifically, this method relies on printing complex 3D objects efficiently replicated into polymeric substrates via soft lithography, resulting in a free-standing polymeric lattice (PL) membrane that can be transferred onto gold-coated MNs and used for electrochemical biosensing. This platform shows excellent electrochemical performance in detecting metabolite (glucose) and protein (insulin) biomarkers with a dynamic linear range sufficient for detecting biomarkers in healthy individuals and patients. The approach holds great potential for fabricating next-generationMNs, including their transfer into clinically adequate devices.
Microneedle-based wearable electrochemical biosensors are the new frontier in personalized health monitoring and disease diagnostic devices that provide an alternative tool to traditional blood-based invasive techniques. Advancements in micro- and nanofabrication technologies enabled the fabrication of microneedles using different biomaterials and morphological features with the aim of overcoming existing challenges and enhancing sensing performance. In this work, we report a microneedle array featuring conductive recessed microcavities for monitoring urea levels in the interstitial fluid of the skin. Microcavities are small pockets on the tip of each microneedle that can accommodate the sensing layer, provide protection from delamination during skin insertion or removal, and position the sensing layer in a deep layer of the skin to reach the interstitial fluid. The wearable urea patch has shown to be highly sensitive and selective in monitoring urea, with a sensitivity of 2.5 mV mM-1 and a linear range of 3 to 18 mM making it suitable for monitoring urea levels in healthy individuals and patients. Our ex vivo experiments have shown that recessed microcavities can protect the sensing layer from delamination during skin insertion and monitor changing urea levels in interstitial fluid. This biocompatible platform provides alternative solutions to the critical issue of maintaining the performance of the biosensor upon skin insertion and holds great potential for advancing transdermal sensor technology.
Wearable technologies have great potential in health monitoring and disease diagnostics. As a consequence, interest in the study of wearable sensors has dramatically increased over recent years. Successful translation of this technology from research prototypes to commercial products requires addressing some of the major challenges faced by wearable sensors such as loss of, and damage in, the biological recognition layer of the skin-interfaced sensors. In this work, we propose a solution to this challenge by integrating micropillar array (MPA) surfaces as part of the sensing layer with the aim to protect and prevent the loss of the enzyme layer from mechanical stress while the sensor is worn. The proposed wearable sensing patch is composed of reference, counter, and working electrodes, all made of MPAs and is designed for measuring glucose in sweat. MPA sensing patch has a wide linear range of 50 μM to 1.4 mM, a sensitivity of 4.7 ± 0.8 μA mM-1, and a limit of detection of 26 ± 5 μM. The glucose sensing patch was tested using human sweat where glucose-level changes were successfully measured before and after meal consumption. The developed patch provides an alternative solution to the problem of the damage to the sensor microenvironment upon wear. But in addition, it also offers a user-friendly, cost-effective, and reliable sweat analysis platform with significant potential in health monitoring applications.
The SARS-CoV-2 (COVID-19) pandemic has emerged as one of the greatest problems of the 21st century worldwide. Efforts to fight this pandemic require a global co-operation and a multidisciplinary approach. An application of information and communication technologies (ICT) to a great degree contributes to fighting the pandemic as these technologies are one of the key services that assist patients, researchers, health institutions and other interested parties in different activities in an effort to fight the pandemic and its consequences. The present paper presents the features of certain mobile applications (apps) that are being used for different purposes such as: tracking patients, COVID-19-related warnings, keeping tracks of statistical data, organising life and business, etc. Aside from presenting the features of a certain number of applications, a review of technologies used for the development of these applications will also be presented. Furthermore, the paper addresses certain challenges that come along with the mobile technologies applications and offers suggestions for future research.
Dairy cattle breeding is one of the most important branches of livestock production, which has been facing, for several decades, the chronic problem of declining reproductive performance. In 2005, the number of cattle worldwide was about 1,370,000,000, while in 2015 that number dropped below one billion, and in 2021 it shows a slight recovery as it was 1,000,970. This indicates the importance of applying different reproductive protocols in order to increase the number of cows in production. The type of bedding on which the animals stay, as well as the characteristics of the lying area itself, shows a significant impact on numerous physiological functions such as food intake, chewing, milk yield, but also levels of sex hormones. The type of bedding and lying area, which causes chronic pain and stress, leads to disorders of physiological and reproductive processes, since stress has direct negative impact on numerous cellular functions. A total of 66 dairy cows, 50 Holstein-Friesian cows kept on PD Butmir and 16 Simmental cows kept on a private mini farm, were included in the study. At PD Butmir, cows were kept in tie-stall housing system, while on a mini-farm they were kept free. Hormonal protocols of estrus and ovulation synchronization were used in April, May and June 2019. Cows were subjected to two estrus synchronization and ovulation protocols, Ovsynch and Cosynch72. At PD Butmir, 25 cows were subjected to Ovsynch and Cosynch72 protocols, respectively. At the mini-farm only Ovsynch protocol was applied. The Ovsynch protocol applied on PD Butmir had success in conception rate of 12% (n = 3), while the Cosynch72 protocol gave a score of 36% (n = 9). On the mini-farm, Ovsynch resulted in a conception of 25% (n = 4). Based on our results, the Cosynch72 protocol, compared to the Ovsynch protocol, was a better choice in the case of Holstein-Friesian cows kept in the tie-stall housing system. In the Simmental cows kept in the free stall system, the Ovsynch protocol proved to be better choice in achieving conception, compared to the Holstein-Friesian cows. Therefore, it is necessary to test several different protocols of estrus and ovulation synchronization, in order to find the most optimal one for a certain breed, type of keeping and breeding.
Ova stranica koristi kolačiće da bi vam pružila najbolje iskustvo
Saznaj više