Beijing Institute of Technology: Development of MOF microneedle sensor for visual detection of stress hormones

Recently, Qi Xiaoyue's research group at Beijing Institute of Technology reported a type of europium metal organic framework microneedle（ Eu-MOF@PAH The MN sensor integrates efficient sampling of microneedles and the optical sensing characteristics of Eu-MOF, providing a painless, minimally invasive, convenient and efficient visual microneedle detection platform for the physical examination and real-time analysis of stress hormones.

Cortisol (CORT), also known as stress hormone, is an important biomarker in stress, involved in regulating carbohydrate metabolism, regulating blood pressure, promoting gluconeogenesis, etc. Its abnormal secretion disrupts the homeostasis of cardiovascular, immune, renal, skeletal, and endocrine systems, leading to systemic metabolic disorders and chronic diseases.The research team has developed a wearable microneedle array based on Eu-MOF, which can achieve visual detection of pressure hormones in vivo (Figure 1), providing an effective strategy for visual monitoring and early warning of pressure.

Firstly, the author constructed Eu-MOF using Eu3+as the central metal and H3BTB as the ligand through solvent thermal method, and conducted a detailed study on its structure, properties, and CORT response ability.Meanwhile, potential interfering molecules such as amino acids, proteins, glucose, and salt ions were used to investigate their selectivity and evaluate the potential application of Eu MOF in complex biological samples

In addition, the author conducted molecular dynamics simulations and analyzed the fluorescence characteristics of Eu MOF and CORT before and after sensing, in depth exploring and elucidating the sensing mechanism of Eu MOF on CORT. CORT adheres to the surface of Eu MOF through physical adsorption under strong interactions, forming a non luminescent Eu MOF CORT complex, which leads to static fluorescence quenching, confirming its potential application value in visual detection of CORT

Then Eu-MOF with CORT selective recognition characteristics was loaded into gel microneedles and prepared by UV curing Eu-MOF@PAH MN (Figure 4). This microneedle patch can withstand a normal stress of 15 N and has excellent mechanical properties, which can effectively penetrate simulated skin and mouse skin tissues.Its excellent swelling performance (swelling rate exceeding 150%) and low dissolution rate (less than 0.1% after 24 hours) ensure that the microneedle can quickly achieve ISF sampling and target analyte capture and sensing detection after penetrating skin tissue.

In vitro experimental data shows that the microneedle exhibits excellent sampling ability and efficiency in simulating skin and mouse skin, achieving the best detection effect of CORT within 10 minutes. Effective detection of CORT within a wide dynamic range of 10-7-10-3 M can be achieved, with a detection limit of 10-9 M, indicating Eu-MOF@PAH MN has extremely high sensitivity in detecting CORT, covering the detection range of normal physiological and pathological states of the human body.More importantly, different batches of Eu-MOF@PAH The effect of MN and CORT is the same. Moreover, the consistent response of the microneedle to CORT after one week of standing proves that the microneedle has good stability.

Based on the above research findings, the author further constructed an acute stress model to validate it Eu-MOF@PAH The high sensitivity and selectivity of microneedle sensing can effectively distinguish CORT levels in resting state (200.98 ± 17.67 ng/mL) and stress state (294.38 ± 32.15 ng/mL). Histological analysis results show that microneedle patches have good biosafety.

Using in acute stress models Eu-MOF@PAH Detect in vivo CORT and evaluate biosafety using MNs. In summary, this study successfully developed an integrated microneedle sensor with high sensitivity, high selectivity, and good biosafety, which can achieve real-time detection of in vivo CORT and elucidate the sensing mechanism of CORT induced Eu MOF fluorescence quenching.In the future, by combining portable imaging devices and smartphones, this strategy can effectively promote the development of bedside and home monitoring technology, and has enormous potential for application and clinical translation ability in early warning of abnormal secretion of stress hormones.

Source: Sensor Expert Network