The next generation of hybrid microfluidic/integrated circuit chips: recent and upcoming advances in high-speed, high-throughput, and multifunctional lab-on-IC systems

3D-printed shadow masks for micro-patterned electrodes

Microfabrication is critical to the advancement of lab-on-chip devices by enabling the creation of high-precision, complex electrode structures. Traditional photolithography, commonly used to fabricate micro-patterned electrodes, involves complex and multi-step processes that can be costly and time-consuming. In this research, we present a method using 3D-printed shadow masks for electrode fabrication, offering a simpler, cost-effective alternative to traditional methods. Specifically, by leveraging a fused deposition modeling 3D printer, we demonstrate that 3D-printed shadow masks streamline rapid prototyping of micro-patterned electrodes with a range of designs, from simple lines to complex patterns. To assess the lab-on-chip functionality of the electrodes fabricated from 3D-printed shadow masks, we investigate electric field-driven assembly of microparticles in the electrodes. The micro-patterned designs of the electrodes remotely guide the assembly patterns, resulting in the formation of well-defined, multiple chains and anisotropic structures. These results suggest that 3D-printed shadow masks not only simplify the fabrication process, but also maintain the precision required for advanced lab-on-chip applications. The proposed method could pave the way for more accessible and scalable manufacturing of the complex micro-patterned electrodes.

Assessment of chemotherapeutic effects on cancer cells using adhesion noise spectroscopy

With cancer as one of the leading causes of death worldwide, there is a need for the development of accurate, cost-effective, easy-to-use, and fast drug-testing assays. While the NCI 60 cell-line screening as the gold standard is based on a colorimetric assay, monitoring cells electrically constitutes a label-free and non-invasive tool to assess the cytotoxic effects of a chemotherapeutic treatment on cancer cells. For decades, impedance-based cellular assays extensively investigated various cell characteristics affected by drug treatment but lack spatiotemporal resolution. With progress in microelectrode fabrication, high-density Complementary Metal Oxide Semiconductor (CMOS)-based microelectrode arrays (MEAs) with subcellular resolution and time-continuous recording capability emerged as a potent alternative. In this article, we present a new cell adhesion noise (CAN)-based electrical imaging technique to expand CMOS MEA cell-biology applications: CAN spectroscopy enables drug screening quantification with single-cell spatial resolution. The chemotherapeutic agent 5-Fluorouracil exerts a cytotoxic effect on colorectal cancer (CRC) cells hampering cell proliferation and lowering cell viability. For proof-of-concept, we found sufficient accuracy and reproducibility for CAN spectroscopy compared to a commercially available standard colorimetric biological assay. This label-free, non-invasive, and fast electrical imaging technique complements standardized cancer screening methods with significant advances over established impedance-based approaches.

Keeping Analytical Chemistry Training Up-to-Date

The undergraduate analytical chemistry curriculum serves to equip students with the knowledge and skills for work outside of classroom training. As such, instructors face a challenging task in deciding the breadth and depth of topics for their courses to ensure their syllabi can remain up-to-date with today's needs. We propose that instructors consider covering capillary electrophoresis (CE) and lab-on-a-chip (LOC) technologies in their analytical chemistry courses. Past surveys of the curriculum show a noticeable lack of emphasis on these topics, which we feel is a missed opportunity and one that holds potential for the collective benefit of instructors and students. CE and LOCs are utilized in a diverse array of fields like biochemistry, pharmaceutical production, materials science, and environmental analysis, and their applications are becoming increasingly important amidst the growing movement toward environmentally sustainable practices and green chemistry. They are also more accessible in the analytical chemistry classroom compared with typical benchtop instruments due to the flexibility of their size and cost. This makes them easier to obtain, maintain, and transport for use and demonstration purposes. Additionally, interwoven in these topics are core concepts that are fundamental to analytical chemistry; thus, covering them will inherently reinforce students' understanding of fundamental knowledge. Therefore, we believe increased coverage of CE and LOCs can better prepare undergraduates for modern analytical chemistry work in various industries and fields of research.

Multiplexed immunosensing of cancer biomarkers on a split-float-gate graphene transistor microfluidic biochip

This work reports the development of a novel microfluidic biosensor using a graphene field-effect transistor (GFET) design for the parallel label-free analysis of multiple biomarkers. Overcoming the persistent challenge of constructing μm2-sized FET sensitive interfaces that incorporate multiple receptors, we implement a split-float-gate structure that enables the manipulation of multiplexed biochemical functionalization using microfluidic channels. Immunoaffinity biosensing experiments are conducted using the mixture samples containing three liver cancer biomarkers, carcinoembryonic antigen (CEA), α-fetoprotein (AFP), and parathyroid hormone (PTH). The results demonstrate the capability of our label-free biochip to quantitatively detect multiple target biomarkers simultaneously by observing the kinetics in 10 minutes, with the detection limit levels in the nanomolar range. This microfluidic biosensor provides a valuable analytical tool for rapid multi-target biosensing, which can be potentially utilized for domiciliary tests of cancer screening and prognosis, obviating the need for sophisticated instruments and professional operations in hospitals.