State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, School of Mathematics and Physics, China University of Geosciences, Wuhan 430074, China.
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
ACS Nano. 2023 Jun 27;17(12):11935-11945. doi: 10.1021/acsnano.3c04017. Epub 2023 Jun 7.
Functional probes not only at the inner wall but also at the outer surface of nanochannel systems could be used for the recognition and detection of biotargets. Despite the advancements, the current detection mechanisms are still mainly based on the surface charge variation. We proposed a strategy of using the variation of wettability on the outer surface of nanochannels for detecting a tumor marker, herein, exemplifying matrix metalloproteinase-2 (MMP-2). The outer surface of the nanochannels were modified with amphipathic peptide probe consisting of hydrophilic unit (CRRRR), MMP-2 cleavage unit (PLGLAG), and hydrophobic unit (Fn). After recognition of MMP-2, due to the release of hydrophobic unit, the hydrophilicity of the outer surface was expected to increase, thus leading to the increase of ion current. Furthermore, the number (n) of phenylalanine (F) in the hydrophobic unit was modulated from 2, 4, to 6. By lengthening the hydrophobic unit, the limit of detection for MMP-2 detection could reach 1 ng/mL (when n = 6) and improve by 50-fold (to n = 2). This nanochannel system was utilized to successfully detect the MMP-2 secreted from cells and demonstrated that the expression of MMP-2 was related to the cell cycle and exhibited the highest level in G1/S phase. This study proved that in addition to the surface charge, wettability regulation could also be utilized as a variation factor to broaden the design strategy of a probe on OS to achieve the detection of biotargets.
功能探针不仅可以在内壁上，还可以在外壁上的纳米通道系统中使用，用于识别和检测生物靶标。尽管取得了进展，但当前的检测机制仍然主要基于表面电荷变化。我们提出了一种利用纳米通道外壁润湿性变化来检测肿瘤标志物的策略，这里以基质金属蛋白酶-2（MMP-2）为例。纳米通道的外壁用由亲水单元（CRRRR）、MMP-2 切割单元（PLGLAG）和疏水单元（Fn）组成的两亲性肽探针进行修饰。在 MMP-2 识别后，由于疏水单元的释放，预计外壁的亲水性会增加，从而导致离子电流增加。此外，疏水单元中的苯丙氨酸（F）数量（n）从 2、4 增加到 6。通过延长疏水单元，MMP-2 检测的检测限可达到 1ng/mL（当 n = 6），并提高了 50 倍（n = 2）。该纳米通道系统成功地检测了细胞分泌的 MMP-2，并证明 MMP-2 的表达与细胞周期有关，在 G1/S 期表达水平最高。这项研究证明，除了表面电荷之外，润湿性调节也可以作为一个变化因素，拓宽 OS 上探针的设计策略，以实现生物靶标的检测。
