Abstract Diamond's properties, such as chemical stability and low biofouling rates, make it an ideal material for developing more adequate biosensing technology for single-use bioreactors. We propose a simplistic approach to covalently functionalizing diamond and evaluating the effects of different variables on the sensitivity of the bioactive surface. We hypothesize that by maximizing sensitivity, we can maximize the signal-to-noise ratio of the biosignal. Three different methods of achieving an oxygenated surface on diamond with varying crystal sizes is investigated to see which results in the most active biointerface. Surface termination species were confirmed post‑oxygenation with X-ray Photoelectron Spectroscopy. The diamond was then functionalized with a biotinylated monolayer, which was treated with gold-conjugated streptavidin to quantify the available bonding sites. After complete biofunctionalization, detection sensitivity of IL-8 and antibody density were assessed with ELISA and electrochemical impedance spectroscopy for quantification of sites with functional antibodies. The contradicting correlations between diamond morphology and percentage of C O bonds lead us to conclude that the effectiveness of oxygen-termination method is independent of diamond morphology. Through quantifying bonding sites, it was found that both the number of available sites and active sites increased with increasing crystal size. This result is suspected to be directly correlated to the hybridization of the diamond-carbon material in that functional species prefer sp3 carbon over sp2. Therefore, a diamond film with the largest possible crystals is predicted to have a higher detection sensitivity in biosensing applications.

中文翻译：

---

表面终止、晶体尺寸和键合位点密度对金刚石生物传感表面的影响

摘要 金刚石的化学稳定性和低生物污染率等特性使其成为为一次性生物反应器开发更合适的生物传感技术的理想材料。我们提出了一种简单的方法来共价功能化金刚石并评估不同变量对生物活性表面敏感性的影响。我们假设通过最大化灵敏度，我们可以最大化生物信号的信噪比。研究了在具有不同晶体尺寸的金刚石上实现氧化表面的三种不同方法，以查看哪种方法会产生最活跃的生物界面。用 X 射线光电子能谱法确认了氧化后的表面终止物质。然后用生物素化的单层对钻石进行功能化，用金缀合的链霉亲和素处理以量化可用的结合位点。完成生物功能化后，用 ELISA 和电化学阻抗谱评估 IL-8 的检测灵敏度和抗体密度，以量化具有功能性抗体的位点。金刚石形态与 CO 键百分比之间相互矛盾的相关性使我们得出结论，氧终止方法的有效性与金刚石形态无关。通过量化键合位点，发现可用位点和活性位点的数量都随着晶体尺寸的增加而增加。该结果被怀疑与金刚石-碳材料的杂化直接相关，因为功能物种更喜欢 sp3 碳而不是 sp2。所以，