Sensing of proteins in human serum using conjugates of nanoparticles and green fluorescent protein


There is a direct correlation between protein levels and disease states in human serum, which makes it an attractive target for sensors and diagnostics. However, this is challenging because serum features more than 20,000 proteins, with an overall protein content greater than 1 mM. Here we report a sensor based on a hybrid synthetic–biomolecule that uses arrays of green fluorescent protein and nanoparticles to detect proteins at biorelevant concentrations in both buffer and human serum. Distinct and reproducible fluorescence-response patterns were obtained from five serum proteins (human serum albumin, immunoglobulin G, transferrin, fibrinogen and α-antitrypsin), both in buffer and when spiked into human serum. Using linear discriminant analysis we identified these proteins with an identification accuracy of 100% in buffer and 97% in human serum. The arrays were also able to discriminate between different concentrations of the same protein, as well as a mixture of different proteins in human serum.

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Figure 1: Modes of sensor response and structural features of NPs.
Figure 2: Array-based sensing of five serum proteins in 5 mM sodium phosphate buffer (pH 7.40).
Figure 3: Determination of the optimum ratio of fluorophore to NP concentration.
Figure 4: Array-based sensing of five serum proteins in human serum.
Figure 5: Discrimination of HSA and IgG at different concentrations and mixtures of proteins.


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This work was supported by the National Science Foundation Center for Hierarchical Manufacturing at the University of Massachusetts and the National Institutes of Health.

Author information

M.D., S.R. and V.R. conceived and designed the experiments. M.D., S.R., H.A., O.M. and R.A. performed the experiments. M.D., S.R., O.M. and V.R. analysed the data. M.D., S.R., U.B. and V.R. co-wrote the paper.

Correspondence to Vincent M. Rotello.

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De, M., Rana, S., Akpinar, H. et al. Sensing of proteins in human serum using conjugates of nanoparticles and green fluorescent protein. Nature Chem 1, 461–465 (2009).

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