Improved DNA chip with poly(amidoamine) dendrimer peripherally modified with biotin and avidin

Abstract

Important properties for a biosensor are the sensitive detection of target DNA at low concentration, the specific and accurate distinction of the target and other DNA having a similar sequence, and measurement capability over a wide range of target concentrations. To these ends, generation 3 polyamidoamine (PAMAM) dendrimer was used to improve DNA chip properties. PAMAM dendrimer surface amine moieties were modified to biotin and immobilized on glass slides using biotin-avidin conjugation. The surface morphologies of the avidin-biotin-dendrimer complexes were observed using atomic force microscopy and scanning electron microscopy. Detection sensitivity for fluorescence-labeled target DNA increased approximately 4-fold by the dendrimer coating. Dendrimer coating also markedly improved the dynamic range and detection of single nucleotide polymorphisms. Dendrimer complex morphology had little effect on the sensitivity. © KSBB

Chemical strategies for immobilization of oligonucleotides

“…Also, a dendrimer coat acts as a spacer between probe and the substrate surface, which facilitates efficient binding and accessibility of the immobilized probe to target. In a diverse approach, Lim et al [79] developed an improved protocol for the fabrication of a DNA biochip with PAMAM dendrimers peripherally modified with biotin and avidin. Biotinyl-oligonu-cleotides were tethered to the surface and the biochips were evaluated with respect to various parameters commonly employed in the microarray experiments.…”

Development of surface chemistry for surface plasmon resonance based sensors for the detection of proteins and DNA molecules

“…Various generations of PAMAM dendrimer were also employed for the development of DNA chips by different research groups [22,23]. Lim and colleagues [24] studied 3 rd generation PAMAM dendrimer-modified surfaces using interaction between avidin and biotin molecules to improve DNA chip properties and showed that dendrimer coating increased the fluorescence intensity due to hybridisation of target DNA tagged with fluorescence dye.…”

Biotinylated Phosphorus Dendrimers as Control Line in Nucleic Acid Lateral Flow Tests

“…The valeric acid side chain of the biotin molecule can be derivatized to incorporate reactive groups that are used to attach biotin to biomolecules, including peptides, antibodies, enzymes, receptors, nucleic acids, and lately dendrimers, without significantly altering their biological activity. 28 Biotinylated PAMAM dendrimers have been used as drug delivery nanocarriers for cancer therapy and diagnosis, 29−33 a versatile platform for other biomedical applications, 34 DNA chips, 35 contrast agents for MR imaging, 36 and important components in electrochemiluminescence biosensors. 37 Other biotinylated dendrimers are rare; only two examples of Lglutamic acid and poly(lysine) internal structures have been used as drug carriers.…”

“…Biotinylated PAMAM dendrimers have been used as drug delivery nanocarriers for cancer therapy and diagnosis, − a versatile platform for other biomedical applications, DNA chips, contrast agents for MR imaging, and important components in electrochemiluminescence biosensors . Other biotinylated dendrimers are rare; only two examples of l -glutamic acid and poly­(lysine) internal structures have been used as drug carriers. , An example of special biotinylated DNA dendrimers has been patented as part of the conjugate path in lateral-flow assays to amplify the desired signal, playing a similar role as previously reported positively charged PAMAM dendrimers. , Phosphorus dendrimers (PPH) are robust structures also used for sensor applications. , A micromechanical biosensor based in DNA–PPH dendrimers hybridized with biotinylated oligonucleotides has been reported, with biomolecular recognition based on their interaction with streptavidin-conjugated gold nanoparticles .…”