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A novel bioreactor for combined magnetic resonance spectroscopy and optical imaging of metabolism in 3D cell cultures
摘要： Purpose: Fluorescence lifetime imaging microscopy (FLIM) of endogenous fluorescent metabolites permits the measurement of cellular metabolism in cell, tissue and animal models. In parallel, magnetic resonance spectroscopy (MRS) of dynamic nuclear (hyper)polarized 13C‐pyruvate enables measurement of metabolism at larger in vivo scales. Presented here are the design and initial application of a bioreactor that connects these 2 metabolic imaging modalities in vitro, using 3D cell cultures. Methods: The model fitting for FLIM data analysis and the theory behind a model for the diffusion of pyruvate into a collagen gel are detailed. The device is MRI‐compatible, including an optical window, a temperature control system and an injection port for the introduction of contrast agents. Three‐dimensional printing, computer numerical control machining and laser cutting were used to fabricate custom parts. Results: Performance of the bioreactor is demonstrated for 4 T1 murine breast cancer cells under glucose deprivation. Mean nicotinamide adenine dinucleotide (NADH) fluorescence lifetimes were 10% longer and hyperpolarized 13C lactate:pyruvate (Lac:Pyr) ratios were 60% lower for glucose‐deprived 4 T1 cells compared to 4 T1 cells in normal medium. Looking at the individual components of the NADH fluorescent lifetime, τ1 (free NADH) showed no significant change, while τ2 (bound NADH) showed a significant increase, suggesting that the increase in mean lifetime was due to a change in bound NADH. Conclusion: A novel bioreactor that is compatible with, and can exploit the benefits of, both FLIM and 13C MRS in 3D cell cultures for studies of cell metabolism has been designed and applied.
关键词： multimodal,optical imaging,bioreactor,magnetic resonance spectroscopy (MRS),nicotinamide adenine dinucleotide (NADH),metabolism,fluorescence lifetime imaging (FLIM),lactate production
更新于2025-09-23 15:22:29
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Localized Surface Plasmon Resonance Based Tapered Fiber Optic Ethanol Sensor
摘要： Ethanol is mostly found in drinks, food, beverages and in the human body fluids, e.g. urine, serum, sweat, saliva, and blood etc. A high concentration of ethanol in body fluids causes various metabolic disorders like diabetes, cirrhosis and hepatitis. Therefore, the detection of ethanol is essential for clinical and forensic investigation. In this study, we report the fabrication and characterization of a localized surface plasmon resonance (LSPR) based tapered fiber optic ethanol sensor. Nowadays LSPR is a very useful technique for biosensing applications. For the LSPR phenomenon, the size of the nanoparticles should be smaller than the wavelength of the light. When an electromagnetic wave is incident on metal nanoparticles, the collective oscillation of the free electrons inside the metal nanoparticles occurs. The maximum amplitude occurs when the frequency of oscillation matches with the frequency of the incident light. Due to the frequency matching a strong field enhancement is observed around the nanoparticles. In the phenomenon called as LSPR, the peak absorbance wavelength depends on the dielectric constant of the medium surrounding the nanoparticles. To fabricate the LSPR based fiber optic probe for ethanol sensing, we have synthesized gold nanoparticles (AuNP) using Turkevich method. The TEM image of AuNPs is shown in fig. 1 (a). The schematic of the LSPR probe is shown in fig 1 (b). The probe is consists of AuNPs over the core of the tapered optical fiber followed by the immobilized layer of enzyme alcohol dehydrogenase (ADH) and coenzyme nicotinamide adenine dinucleotide (NAD). For the attachment of gold nanoparticles the core was cleaned by pirhana solution and kept in amino silane solution. Dip coating was used to coat the AuNPs over the silanized core. After this, the probe was incubated in 1 mM aqueous solution of cystamine dihydrochloride for 1 h for attachment of –NH2 groups over the AuNPs-coated fiber core. Finally, the probe was incubated for 12 h into the ADH and NAD solution. This completed the probe fabrication step.
关键词： Ethanol Sensor,Alcohol Dehydrogenase,Tapered Fiber Optic,Localized Surface Plasmon Resonance,Nicotinamide Adenine Dinucleotide,Gold Nanoparticles
更新于2025-09-11 14:15:04