Periodic Reporting for period 2 - DNA-BIO (Diamond based nanomaterials for biosensing applications)
Reporting period: 2024-01-01 to 2024-12-31
Biosensors are analytical devices that encompass a sensitive biological detection material or a biological receptor capable of offering ultrasensitive detection of markers specific for diseases. Nanomaterials and nanostructures in particular diamond-based materials exhibit attractive properties for biosensing, but their fabrication presents with technical challenges. The evolution of next-generation, integrated, multi-functional sensing, monitoring, and non-destructive techniques calls for the integration of miniaturized sensors into microchips, such as microelectromechanical systems (MEMS). Recent progress in nanotechnology, along with innovative approaches to synthesizing nanomaterials and fabricating MEMS devices, has simplified the design and development of advanced sensing strategies and portable devices. The project developed novel diamond nanostructures that can be selectively functionalised on their surface to serve specific sensing applications including biological sensing and imaging. The outcome is the introduction of the next generation of high-resolution biosensors and/or electrochemical sensors to both the research community and the biomedical field. We have successfully demonstrated diamond MEMs sensors, with promising biomedical applications in the fields of atomic force microscopy probes, magnetic sensors, and mass sensors. We also demonstrated electrochemical sensors, which are promising tools for monitoring metabolic conditions such as gout related disorders. Its fast response and compatibility with wearable and portable health monitoring devices further highlight its potential applications in clinical diagnostics, biomedical research, and environmental sensing.
We employed microwave plasma-enhanced chemical vapor deposition system to grow thin diamond films. We systematically analysed the samples using laser optical microscopy, atomic force microscopy, and X-ray diffraction to understand their crystal structure and morphology. The crystalline phase was identified using X-ray and electron diffraction techniques, while the specific structure of individual nanocrystals, including their crystalline planes, growth orientations, and interfaces, was examined. To comprehend the photoluminescence phenomena associated with defects within the diamond crystals, we utilized photoluminescence spectroscopy to characterize various diamond samples. Fluorescence images revealed a clear correlation between defects and characteristic photoluminescence peaks. Using high-quality samples, we fabricated diamond-based cantilever nanostructures with higher-order resonances. The resonance frequency of these diamond cantilevers remained consistent in both experimental observations and theoretical predictions under higher-order modes. Despite the low Q factor primarily attributed to crystal defects within the cantilever, the f‧Q product significantly improved by over 15 times compared to the fundamental mode resonance. These results suggest promising biomedical applications in the fields of atomic force microscopy probes, magnetic sensors, and mass sensors. We also studied a new type of electrochemical sensor based on metal-organic frameworks (MOF) structures. This sensor is designed to improve the detection of uric acid in interstitial fluid (ISF) by combining the advanced features of MOFs with a specially designed 3D-printed device that has a microvalve. We used a novel method to form Eu embedded MOF nanoparticles for modifying a screen-printed electrode (SPE), which boosted its ability to catalyze reactions. Additionally, the 3D-printed device included a microvalve that carefully controlled the flow of fluids and connected to a vacuum tube, allowing for effective and safe extraction of ISF without contamination. This setup provided a more stable environment for detecting uric acid in ISF, addressing issues like slow extraction rates and potential skin damage. Our sensor showed excellent sensitivity, selectivity, reproducibility, and stability across various UA levels, achieving a low limit of detection and high recovery rates These qualities make the developed sensor a promising tool for monitoring metabolic conditions such as gout and related disorders. Its ease of use, quick response time, and compatibility with wearable and portable health monitoring devices further highlight its potential applications in clinical diagnostics, biomedical research, and environmental sensing.
The evolution of next-generation biosensors calls for the integration of miniaturized sensors into microchips, such as microelectromechanical systems (MEMS). Recent progress in nanotechnology, along with innovative approaches to synthesizing nanomaterials and fabricating MEMS devices, has simplified the design and development of advanced sensing strategies and portable devices. MEMS, emerging as pivotal technologies, play an increasingly vital role in a wide range of applications, from classic use like sensing, actuation, and switches in environmental monitoring, smart phones, IoT nodes, robotic servants, and autonomous vehicles to precise quantum sensors. Resonance frequency (f) and quality factor (Q) are two fundamental parameters determining the performance of the MEMS sensors, such as response speed, detectivity, stability, and signal-to-noise ratio. When sensing is based on the frequency shift, Q factor is of paramount importance. However, increasing the resonance frequency always leads to the degradation of the Q factor for the fundamental resonance mode due to increased dissipation in the system. Therefore, the product of f‧Q presents as a figure of merit for MEMS resonators. High f‧Q product is generally desirable to achieve high sensitivity, fast response speed, and enhanced resilience to mechanical noise sources. Diamond has been considered the best candidate for high-performance and high-reliability MEMS sensors in terms of its exceptional mechanical, thermal, and chemical properties. Despite the theoretical f‧Q of diamond in Akhieser regime is lower than Si, the practical Q factor over 1 million at room temperature was achieved, much higher than that of Si. By using diamond cantilevers, the durability of the AFM probe and the reliability of magnetic or mass sensors under extreme conditions can be much improved. We fabricated single-crystal diamond (SCD) cantilevers with the higher-order resonance and the f‧Q at different resonance modes. Remarkably, with little change of the Q factors at the higher-order resonance, the f‧Q product of the SCD increased by over 15 times, for the third order resonance relative to the first order resonance. The progress provides a promising application scene for SCD MEMS cantilevers, such as AFM probes, magnetic/mass sensors. We also performed ion implantation of nitrogen and rare-earth elements; and the introduction and manipulation of nitrogen-vacancy color centres and evaluation by using both Ion implantation facilities and focused ion beam in the UK to produce the high performance devices and sensors. We also developed a novel electrochemical sensor, based on the high-performance characteristics of MOFs with an innovative 3D-printed HMNsAP equipped with a microvalve. Our work integrated the novel strategy to in increase the electrocatalytic activity. Additionally, the developed microvalve could precisely regulate fluid flow when connected to a vacuum tube, enabling efficient and contamination risk-free ISF extraction.