Carboxylated/Oxidized Diamond Nanoparticles for Quantifying Immunoglobulin G Antibodies Using Mass Spectrometry
Carboxylated/Oxidized Diamond Nanoparticles for Quantifying Immunoglobulin G Antibodies Using Mass Spectrometry
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DOI：
10.1021/acsanm.1c01553
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发表时间：
2021-09
影响因子：
5.9
通讯作者：
Avinash A. Patil;M. J. N. Descanzo;Justin Benedict A. Agcaoili;Cheng‐Kang Chiang;Chia‐Liang Cheng;Huan‐Cheng Chang;W. Peng
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文献类型：
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作者：
Avinash A. Patil;M. J. N. Descanzo;Justin Benedict A. Agcaoili;Cheng‐Kang Chiang;Chia‐Liang Cheng;Huan‐Cheng Chang;W. Peng
抗体结合纳米金刚石（ND）最近受到生物医学领域研究人员的相当大的关注。准确定量ND表面上的抗体（Ab）表面覆盖对于提高药物递送和免疫治疗应用中的灵敏度至关重要。我们首次提出高亲和力羧化/氧化ND颗粒可用于直接定量抗体，即，免疫球蛋白G（IgG），在纳摩尔（nM）浓度范围内，使用基质辅助激光解吸电离飞行时间质谱。用两种不同的ND，即，羧化高压高温ND（HPHT ND）和空气氧化爆轰ND（oxDND），显示和定量分析使用Langmuir-Freundlich等温线模型。固定化IgG的最低可检测浓度对于HPHT ND为10 nM，对于oxDND为14 nM。每个HPHT ND颗粒和oxDND颗粒的IgG分子的最低可检测表面覆盖率分别为1001140和100700 IgG。IgG单分子层固定在oxDND表面，oxDND的最大吸附量高于HPHT ND。此外，通过分析hCG-β Ab-oxDND缀合物和hCG-β Ab-Mag-Beads蛋白G缀合物识别的hCG抗原的离子信号，证实了大多数hCG（人绒毛膜促性腺激素）-β Ab在oxDND表面上的取向可能是尾部。与商业Ab-Mag-Beads蛋白G缀合物相比，hCG-β Ab-oxDND缀合物不需要蛋白G作为抗体的接头，并且可以用作免疫诊断中的简单抗体-抗原平台。
Antibody-conjugated nanodiamonds (NDs) have recently received considerable attention from researchers in the biomedical fields. Accurately quantifying antibody (Ab) surface coverage on ND surfaces is critical to improve sensitivity in drug delivery and immunotherapy applications. We present for the first time that high affinity carboxylated/oxidized ND particles are useful to directly quantify antibodies, i.e., immunoglobulin G (IgG), in the nanomolar (nM) concentration range using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The adsorption of IgG molecules with two different NDs, i.e., carboxylated high-pressure high-temperature ND (HPHT ND) and air-oxidized detonation ND (oxDND), is shown and is quantitatively analyzed using the Langmuir–Freundlich isotherm model. The lowest detectable concentrations of immobilized IgG are ∼10 nM for HPHT ND and ∼4 nM for oxDND. The lowest detectable surface coverages of IgG molecules per single HPHT ND particle and oxDND particle are ∼1140 and ∼700 IgG, respectively. The IgG monolayer is immobilized on the oxDND surface, and the maximum adsorption capacity of oxDND is higher than that of HPHT ND. Moreover, the orientation of most hCG (human chorionic gonadotropin)-β Abs on the oxDND surface is probably tail-on, as verified by analyzing the ion signal of the hCG antigen recognized by the hCG-β Ab-oxDND conjugate and by the hCG-β Ab-Mag-Beads Protein G conjugate. Compared to the commercial Ab-Mag-Beads Protein G conjugate, the hCG-β Ab-oxDND conjugate does not require Protein G as a linker to the antibody and can be used as a simple antibody–antigen platform in immunodiagnostics.