Bioassay of prostate-specific antigen (PSA) using microcantilevers

Abstract

Diagnosis and monitoring of complex diseases such as cancer require quantitative detection of multiple proteins. Recent work has shown that when specific biomolecular binding occurs on one surface of a microcantilever beam, intermolecular nanomechanics bend the cantilever, which can be optically detected. Although this label-free technique readily lends itself to formation of microcantilever arrays, what has remained unclear is the technologically critical issue of whether it is sufficiently specific and sensitive to detect disease-related proteins at clinically relevant conditions and concentrations. As an example, we report here that microcantilevers of different geometries have been used to detect two forms of prostate-specific antigen (PSA) over a wide range of concentrations from 0.2 ng/ml to 60 microg/ml in a background of human serum albumin (HSA) and human plasminogen (HP) at 1 mg/ml, making this a clinically relevant diagnostic technique for prostate cancer. Because cantilever motion originates from the free-energy change induced by specific biomolecular binding, this technique may offer a common platform for high-throughput label-free analysis of protein-protein binding, DNA hybridization, and DNA-protein interactions, as well as drug discovery.

AFM fishing nanotechnology is the way to reverse the Avogadro number in proteomics

“…As a result, proteomics is limited by the concentration sensitivity of existing technologies that are unable, despite the successful development of MS, 2-D-electrophoresis, multidimensional chromatography, and a variety of other methods, to overcome the CSL of 10 212 M (Table 1) [6][7][8][9][10][11][12][13].…”

Cantilever biosensors for detection of viruses and bacteria

“…Кантилеверные сен соры позволяют определять белки, являющиеся маркерами различных заболеваний. Например, показана возможность детектирования простат специфического антигена -маркера заболеваний предстательной железы -на клинически значимом уровне концентраций [5]. В другой работе [6] опре делялась концентрация миоглобина, являюще гося маркером сердечно сосудистых заболеваний.…”

“…Cantilever sensors allow to identify proteins that are markers of various diseases. For example, the possibility of detec tion of prostate specific antigen, a marker of prostate cancer, in clini cally significant concentrations was shown [5]. In another project [6] the concentration of myoglobin, which is a marker of cardiovascular dis eases, was determined.…”

“…За время развития кантилеверных биосенсоров продемонстрировано большое количество прило жений по детекции различных видов биомолекул: белков [5,6], нуклеиновых кислот, углеводов [9]. Была показана возможность зарегистрировать еди ничный нуклеотидный полиморфизм [10].…”

Exploiting nanotechnology to target cancer

“…For example, using a microscale cantilever, Hansen et al (2001) reported that it was possible to discriminate DNA single-nucleotide mismatches. In a separate study, Wu et al (2001) demonstrated the feasibility of the approach to quantify PSA at a clinically relevant concentration. Although both these studies were done using a microscale cantilever, it is not difficult to envisage a future where nanowires and nanotubes will function as the sensors (Zheng et al, 2005), offering the possibility of large-scale monitoring of the proteome or the transcriptome for subtle changes in the profile and relate it to the early stages of cancer progression.…”