Preparation of aptamer-linked gold nanoparticle purple aggregates for colorimetric sensing of analytes

Juewen Liu, Yi Lu

Research output: Contribution to journalArticlepeer-review


Aptamers are single-stranded DNA or RNA molecules that can bind target molecules with high affinity and specificity. The conformation of an aptamer usually changes upon binding to its target analyte, and this property has been used in a wide variety of sensing applications, including detection based on fluorescence intensity, polarization, energy transfer, electrochemistry or color change. Colorimetric sensors are particularly important because they minimize or eliminate the necessity of using expensive and complicated instruments. Among the many colorimetric sensing strategies, metallic nanoparticle-based detection is desirable because of the high extinction coefficients and strong distance-dependent optical properties of the nanoparticles. Here, we describe a protocol for the preparation of aptamer-linked gold nanoparticle purple aggregates that undergo fast disassembly into red dispersed nanoparticles upon binding of target analytes. This method has proved to be generally applicable for colorimetric sensing of a broad range of analytes. The time range for the entire protocol is ∼5 d, including synthesis and functionalization of nanoparticles, preparation of nanoparticle aggregates and sensing.

Original languageEnglish (US)
Pages (from-to)246-252
Number of pages7
JournalNature Protocols
Issue number1
StatePublished - Jun 2006

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology


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