title: Real-time molecular recognition between protein and photosensitizer of photodynamic therapy by quartz crystal microbalance sensor.
abstract: Real-time investigation of molecular recognition between protein and the photosensitizer of photodynamic therapy (PDT) was carried out by a quartz crystal microbalance (QCM) sensor integrated into a flow injection analysis (FIA) system. The photosensitizer meso-tetrakis(4-hydroxyphenyl)porphyrin (p-THPP) was immobilized on the gold electrode of the QCM chip by combining the sol-gel and self-assembly methods. Such a rapid screen analysis of molecular recognition showed that the p-THPP-immobilized sensor exhibited sensitive and specific interaction only with hemoglobin (Hb). The kinetic rate constants (k(ass) and k(diss)) and the equilibrium association constant (K(A)) for p-THPP-Hb interaction were calculated by linear regression. The sensing performance characteristics of the proposed sensor were investigated. The sensor showed excellent selectivity, reproducibility, and repeatability for the detection of Hb. A linear calibration plot was obtained over a range from 0.2 to 1.0 microM with a detection limit (signal/noise ratio=3) of 0.15 microM. The response mechanism of the sensor is discussed in detail. Due to its low cost and simple manipulation, this QCM-FIA system was shown to be a highly effective method for the investigation of interaction between biomacromolecules and the PDT photosensitizer. It also provides a potential strategy for screening an efficient and less harmful photosensitizer for PDT application.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Long
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Li
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Kean
authors.initials: K
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
mesh_terms: D000818:Animals; D002417:Cattle; D002645:Chickens; D002942:Circular Dichroism; D003460:Crystallization; D017022:Flow Injection Analysis; D005470:Fluorometry; D006454:Hemoglobins / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D007700:Kinetics; D046208:Microchip Analytical Procedures / Q000379:methods*; D008958:Models, Molecular; D008968:Molecular Conformation; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000032:analysis* / Q000737:chemistry; D011166:Porphyrins / Q000032:analysis* / Q000737:chemistry; D011791:Quartz / Q000737:chemistry*; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D017319:Photosensitizing Agents; D011166:Porphyrins; C481734:meso-tetra-(4-hydroxyphenyl)porphyrin; D011791:Quartz