title: A Highly Sensitive Porous Silicon (P-Si)-Based Human Kallikrein 2 (hK2) Immunoassay Platform toward Accurate Diagnosis of Prostate Cancer.
abstract: Levels of total human kallikrein 2 (hK2), a protein involved the pathology of prostate cancer (PCa), could be used as a biomarker to aid in the diagnosis of this disease. In this study, we report on a porous silicon antibody immunoassay platform for the detection of serum levels of total hK2. The surface of porous silicon has a 3-dimensional macro- and nanoporous structure, which offers a large binding capacity for capturing probe molecules. The tailored pore size of the porous silicon also allows efficient immobilization of antibodies by surface adsorption, and does not require chemical immobilization. Monoclonal hK2 capture antibody (6B7) was dispensed onto P-Si chip using a piezoelectric dispenser. In total 13 × 13 arrays (169 spots) were spotted on the chip with its single spot volume of 300 pL. For an optimization of capture antibody condition, we firstly performed an immunoassay of the P-Si microarray under a titration series of hK2 in pure buffer (PBS) at three different antibody densities (75, 100 and 145 µg/mL). The best performance of the microarray platform was seen at 100 µg/mL of the capture antibody concentration (LOD was 100 fg/mL). The platform then was subsequently evaluated for a titration series of serum-spiked hK2 samples. The developed platform utilizes only 15 µL of serum per test and the total assay time is about 3 h, including immobilization of the capture antibody. The detection limit of the hK2 assay was 100 fg/mL in PBS buffer and 1 pg/mL in serum with a dynamic range of 106 (10(-4) to 10(2) ng/mL).
authors.affiliation: Bioengineering Laboratory, RIKEN, Saitama 3510198, Japan. SangWook_L@chem.s.u-tokyo.ac.jp.
authors.forename: Sang Wook
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Bioengineering Laboratory, RIKEN, Saitama 3510198, Japan. k-hoso@riken.go.jp.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hosokawa
authors.affiliation: Department of Biomedical Engineering, Dongguk University, Seoul 100715, Korea. skim@dongguk.edu.
authors.forename: Soyoun
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Inje University, Gimhae-si 621-749, Korea. memsoku@inje.ac.kr.
authors.forename: Ok Chan
authors.initials: OC
authors.lastname: Jeong
authors.affiliation: Department of Translational Medicine, Lund University, Skåne University Hospital in Malmö, Malmö 20502, Sweden. liljah@mskcc.org.|Departments of Laboratory Medicine, Surgery (Urology), and Medicine (GU Oncology), Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA. liljah@mskcc.org.|Institute for Biosciences and Medical Technology, University of Tampere, Tampere 33800, Finland. liljah@mskcc.org.|Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX3 7DQ, UK. liljah@mskcc.org.
authors.forename: Hans
authors.initials: H
authors.lastname: Lilja
authors.affiliation: Department of Biomedical Engineering, Dongguk University, Seoul 100715, Korea. thomas.laurell@bme.lth.se.|Department Biomedical Engineering, Lund University, Lund 22100, Sweden. thomas.laurell@bme.lth.se.
authors.forename: Thomas
authors.initials: T
authors.lastname: Laurell
authors.affiliation: Bioengineering Laboratory, RIKEN, Saitama 3510198, Japan. mizuo@riken.jp.
authors.forename: Mizuo
authors.initials: M
authors.lastname: Maeda
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D004867:Equipment Design; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D008297:Male; D046228:Microarray Analysis; D016062:Porosity; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D012825:Silicon / Q000737:chemistry*; D020840:Tissue Kallikreins / Q000032:analysis*
chemical_list: D014408:Biomarkers, Tumor; D020840:Tissue Kallikreins; D012825:Silicon
keywords: antibody microarrays; human kallikrein 2; porous silicon; prostate cancer