37 results about "Northern blot" patented technology

The invention discloses a method for detecting miRNAs by a DIG labeling EDC (carbodiimide) cross-linking bridging method. Once a DIG labeling system is utilized, the sensitivity of the DIG labeling system is improved by at least 50 times in contrast with that of a traditional DIG labeling Northern blots detection system; and the sensitivity of the DIG labeling system is equivalent with that of a radioisotope labeling Northern blots detection system; the method cannot cause any pollution on environment, and is very safe and free of a hybridization step; all operations can be completed in 9-10 hours; and therefore, the method is convenient, quick, and low in detection cost. As a result, the problems of low safety, complex procedure, high price, low sensitivity and the like of a current detection method are solved.

This invention describes methods for the generation of nucleic acid probes that improve the sensitivity of hybridization assays. The sensitivity increase results from structural modifications of nucleic acids that promote network formation during hybridization with the result that a single target molecule becomes attached to a complex of many probe molecules. The structural modification involves fragmentation of the probe nucleic acid followed by joining the fragments together such that their order and orientation and number is altered from the original probe molecule. The result is the generation of permuted probe libraries. Various fragmentation and joining methods are described. Labeling can be done by standard methods before during or after formation of permuted probe libraries. Individual members of permuted probe libraries can be isolated and amplified and perpetuated. Fixed mixtures of such isolated library members can be used as permuted probe libraries of limited variability to control network complexity. Libraries can be prepared with additional sequences not present in the target and the fraction of the library made up by such sequences can be controlled. Such extra-target additions can be used as targets for detection by secondary probes. Since their number can be far greater than equimolar with the probe sequences represented in the target they can be detected with higher sensitivity in the networks. Probes for different targets can incorporate different non-target sequences in hyper-molar quantities permitting sensitive detection of multiple hybridization targets in the same sample. Probes made according to this invention can be used in many kinds of hybridization assay including Southern. blots, Northern blots, Dot blots, Nucleic acid Array hybridization, ‘in situ’ hybridization with fluorescent or other labels (FISH) and various kinds of sandwich hybridization assays.

Provided are DNA microarray techniques that allow hybridization without RNA amplification, without using cDNA, and without labeling the nucleic acid prior to hybridization. Referred to as the Double-stranded Exonuclease Protection (DEP) assay, the technique permits the sample RNA to be used directly for hybridization, without manipulation in any way. Further provided is a microarray technique for high-throughput miRNA gene expression analyses, termed the RNA-primed, Array-based, Klenow Enzyme (RAKE) assay. The RAKE assay is a sensitive and specific technique for assessing single-stranded DNA and RNA targets, and offers specific advantages over Northern blots.