Soft microfiber-based hollow microneedle array for stretchable microfluidic biosensing patch with negative pressure-driven sampling

A Review of Recent Advances in Microneedle-Based Sensing within the Dermal ISF That Could Transform Medical Testing

“…37,42 Unlike solid MNs, hollow MNs have a hollow built-in fluidic channel, which provides significant improvement in sample transfer performance and efficiency, ensuring their superiority in sample delivery and testing. 1 To be suitable for ISF detection, not only will solid MNs be treated but also hollow MNs will be specifically treated, which is similar to solid MNs, and will be chemically modified and biocoated. However, compared with solid MNs, hollow MNs focus more on perfecting the internal fluid channel for the detection of fluid transport because hollow MNs already have a hollow fluid channel; thus, the modification of hollow channels will greatly improve the efficiency of liquid sample detection, which can effectively ensure the smooth extraction, transportation and analysis of extracted samples.…”

“…Schematic diagram of the main structure of the MN sensor: (a) A schematic diagram of the microfluidic sensor structure is shown, in which the microfluidic device comprises four chambers, namely, a blood sample inlet (I), a sensing chamber (S), a liquid chamber (L), and an absorbing chamber (A), as well as an electrochemical biosensor comprising a vacuum suction cup that generates negative pressure and extracts a blood sample, a retractable microfluidic channel to control the delivery of a sample collected by an MN patch into the S chamber, and an electrochemical biosensor based on a flexible screen-printed electrode (SPE). Reproduced from ref . Copyright 2023 Elsevier Ltd. (b) The integrated detection chip consists of three parts: a microchannel layer, a CO 2 penetration layer, and an incubation layer.…”

“…Hollow MNs are usually prepared using polymer materials with high biocompatibility and good mechanical strength, and their dimensions are roughly the same as those of solid MNs, which are in the range of a few micrometers to tens of micrometers, and their lengths are in the range of hundreds of micrometers to a few millimeter; thus, hollow MNs also have penetration performance comparable to that of solid MNs, and their morphology and structure are roughly conical. To improve the penetration properties of hollow MNs, the tip should also be optimized during production, which is necessary to reduce damage to biological tissue. , Unlike solid MNs, hollow MNs have a hollow built-in fluidic channel, which provides significant improvement in sample transfer performance and efficiency, ensuring their superiority in sample delivery and testing …”

“…With the development of personalized medical testing, the public is no longer limited to going to medical institutions for cumbersome health screening , but prefers testing devices that are suitable for personal use . Therefore, for the traditional method of testing blood by drawing blood, these reports have shown that the analytical composition of body fluids is similar to that of blood, and researchers have turned to the study of interstitial fluid (ISF) as an alternative to testing and analyzing blood because ISF contains a large number of cellular metabolites and other important biomarkers that are more similar to those of blood; therefore, researchers have focused on measuring ISF as a measure of health.…”

Recent advances of biosensors on microneedles

“…22–25 Substantial progress has been made in developing microfluidics-based biosensors, but it is a challenging task to achieve a high degree of integration, automation, and miniaturization of the current devices on a single platform. 26 This problem has been partially solved with MN-based biosensors (Fig. 1).…”