Center for Biomedical EPR Spectroscopy and Imaging, The Ohio State University, 420 West 12th Avenue, Room 114, Columbus, OH 43210, USA.
Biomed Microdevices. 2010 Jun;12(3):381-7. doi: 10.1007/s10544-009-9394-5.
Lithium naphthalocyanine (LiNc) is a crystalline material that has significant potential as a probe for EPR (electron paramagnetic resonance)-based biological oximetry (Pandian et al. J. Mater. Chem. 19:4138-4147, 2009a). However, implantation of LiNc crystals in tissues in raw or neat form is undesirable since dispersion of crystals in tissue may lead to loss of EPR signal, while also exacerbating biocompatibility concerns due to tissue exposure. To overcome these concerns, we have encapsulated LiNc crystals in an oxygen-permeable polymer, Teflon AF 2400 (TAF). Fabrication of TAF films incorporating LiNc particles (denoted as LiNc:TAF chip) was carried out using solvent-evaporation techniques. The EPR linewidth of LiNc:TAF chip was linearly dependent on oxygen-partial pressure (pO(2)) and did not change significantly relative to neat LiNc crystals. LiNc:TAF chip responded to changes in pO(2) reproducibly, enabling dynamic measurements of oxygenation in real time. The LiNc:TAF chips were stable in tissues for more than 2 months and were capable of providing repeated measurements of tissue oxygenation for extended periods of time. The results demonstrated that the newly fabricated, highly oxygen-sensitive LiNc:TAF chip will enhance the applicability of EPR oximetry for long-term and clinical applications.
锂萘嵌苯（LiNc）是一种晶体材料，在基于电子顺磁共振（EPR）的生物血氧测定法（Pandian 等人，J. Mater. Chem. 19:4138-4147, 2009a）中具有很大的应用潜力。然而，将 LiNc 晶体直接植入组织中是不理想的，因为晶体在组织中的分散可能导致 EPR 信号丢失，同时也会因组织暴露而加剧生物相容性问题。为了解决这些问题，我们将 LiNc 晶体封装在一种透气聚合物——聚四氟乙烯 AF2400（TAF）中。采用溶剂蒸发技术制备了含有 LiNc 颗粒的 TAF 薄膜（表示为 LiNc:TAF 芯片）。LiNc:TAF 芯片的 EPR 线宽与氧分压（pO2）呈线性关系，与纯 LiNc 晶体相比没有明显变化。LiNc:TAF 芯片能够重复响应 pO2 的变化，实现实时氧合动力学测量。LiNc:TAF 芯片在组织中稳定超过 2 个月，能够长时间提供组织氧合的重复测量。结果表明，新制造的高氧敏性 LiNc:TAF 芯片将增强 EPR 血氧测定法在长期和临床应用中的适用性。
