Reviewed by Lexie CornerJun 12 2024
Researchers from Xi'an Jiaotong University have made a significant breakthrough in biosensor technology, as reported in a recent study published in the journal Engineering. Their novel biosensor offers a promising approach for detecting single-stranded DNA oligonucleotides with high accuracy, paving the way for more effective and accessible point-of-care diagnostics.
CMUTs: capacitive micromachined ultrasonic transducers; SAM: self-assembled monolayer. Image Credit: Zhikang Li et al.
This particular biosensor is built on capacitive micromachined ultrasonic transducers (CMUTs), which have demonstrated potential for creating highly efficient, compact biosensing platforms. Nevertheless, earlier CMUTs had drawbacks, including ineffective functionalization, aggregation, and the need for an external high-voltage (HV) power supply.
The research team integrated the ethylene-glycol alkanethiols utilized to functionalize the surface of the CMUTs with a CMOS front-end interface to overcome these obstacles. This strategy significantly increased the on-chip hybridization's selectivity, as demonstrated by fluorescence imaging technology.
The sensor array was characterized with a five-element lumped equivalent model, and a 0.18-μm HV Bipolar-CMOS-Double diffused MOS (DMOS) application-specific integrated circuit (ASIC) chip measuring 4 mm2 was designed and developed (BCD). The chip's low total power consumption of 3.8 mW in continuous mode allowed it to generate on-chip 20 V HV boosting and track feedback frequency using a standard 1.8 V supply.
The findings of the study demonstrated a 7.943 × 10−3 μmol∙ L−1∙Hz−1 detection sensitivity over a concentration range of 1 to 100 μmol∙L−1. Additionally, improving the selectivity of the biosensor is achieved by the successful deposition of self-assembled monolayers on aluminum electrodes using ethylene-glycol alkanethiols, a first for CMUT technology.
Operating in a dry environment, this label-free biosensing technology is a major advancement in microfabricated CMUT arrays for medical diagnostics. With its small size and internal HV supply, this cutting-edge biosensor promises to make DNA detection easier and more convenient than ever before.
This work has broad implications, as it may lead to fully integrated on-chip DNA biosensing using CMUT technology. Developments like these are essential to enabling fast and precise disease monitoring and diagnosis as the race toward more personalized medicine gains momentum. The biosensor's label-free feature lowers the expense and complexity of conventional labeling methods, making it a desirable choice for point-of-care applications.
The authors note that more research is required to examine the biosensor's functionality with a larger variety of biomolecules and in more intricate sample matrices. On the other hand, the present results offer a solid basis for creating next-generation biosensors that are very specific, sensitive, easy to use, and reasonably priced.
This technology has the potential to revolutionize patient outcomes in an era where early detection is crucial. It might soon find use in various contexts, such as medical offices and remote clinics with limited access to advanced diagnostic tools.
This microfabricated CMUT array with a 2 MHz frequency on CMOS electronics has been successfully demonstrated, paving the way for further developments in the biosensor field. Due to ongoing research and development, even more potent and adaptable biosensing technologies may surface in the upcoming years, completely altering how we identify and treat illnesses.
Journal Reference:
Li, Z., et al. (2024) Development of an Integrated CMUTs-based Resonant Biosensor for Label-Free Detection of DNA with Improved Selectivity by Ethylene-Glycol Alkanethiols. Engineering. doi.org/10.1016/j.eng.2023.12.015