tinto rang is the safest and fastest fluorescent dye outperforms ethidium bromide in any gel system, including agarose and polyacrylamide gels. It is the most sensitive stain for dsDNA, ssDNA and RNA. tinto rang™ can be applied in many fields of study including clinical research and diagnostics, academic research, agricultural research, food safety testing, environmental monitoring, and forensic analysis.

tinto rang is a minor groove / external binding nucleic acid dye that has high affinity and rapidly binds to DNA. It may find potential applications in the making of safe, fluorescence-based Minor Groove Binder (MGB) dyes and probes that have several advantages over DNA intercalating probes in terms of increased stability, sensitivity and specificity.

The five tests mandatory by Food & Drug Administration (FDA) for the donated blood units are HBsAg, HIV, HCV, HBV Ab, VDRL and Malarial parasites. Current testing methods carried out in India are based on the principle of enzyme immunoAssay (EIA). EIA-based blood screening tests detect virus-induced antibodies or viral antigens, not the virus itself and the major disadvantage of these techniques is the seroconversion window (window period), which can be up to 60 days in case of HIV & also, that the EIA screening has a very high rate of false positives. Even the p24 test (an antigen-based test), may at times give negative results in spite of the presence of the pathogen. NAT (Nucleic Acid Testing), on the other hand, always gives a specific and quantitative result as long as there is HIV in someone’s blood and detects the infection at an early stage overcoming the window period and takes only a few hours to days for the analysis. One of the most commonly used nucleic acid dyes in molecular disease diagnostics is SYBR Green.

However, there are various problems associated with SYBR Green-I, such as:

  • It binds even to the nonspecific PCR products such as the primer dimers.

  • Leads to false positive results and,

  • Also inhibits the PCR extension process at higher concentrations.

Because of these issues, there is an increased demand for Minor Groove Binding (MGB) dyes and probes that would not interfere with the amplification process.

Forensic DNA typing often involves samples that are degraded, contaminated and are from multiple unknown sources. Such evidence samples might contain very little amount of nucleic acid that is available for repeating tests and confirming identity. Furthermore, some forensic samples such as DNA from older blood stains may contain factors that inhibit amplification. It is usually remedied by re-extracting the DNA and removing the inhibiting factor. The widely used EtBr intercalates to DNA in a concentration dependent manner and has been shown to alter the DNA and affects the mobility of DNA at high concentrations, thus decreasing the reliability of fragment size measurement and banding pattern. Hence, staining after electrophoresis (i.e., post staining) is recommended as smaller amounts of EtBr is required. However, EtBr being a carcinogen, poses problems of exposure and disposal. It also requires 10-20 minutes of incubation for visualization of results. As EtBr is the widely used stain in DNA Forensics, there are not many alternatives to replace it. tinto rang™ being a small molecule does not affect the mobility of DNA sample and its features such as safety, speed and the property of being a Minor Groove Binder / External Binder (MGB/EB) prove it to be the best alternative to EtBr in DNA forensics.

EtBr vs tinto rang™ in DNA Forensics

Methods Ethidium Bromide tinto rang
In-gel staining Not recommended; affects mobility of DNA and thereby, the pattern Does not affect mobility and DNA pattern
Re-extraction of samples Due to its intercalating property, alters DNA structure that may affect results MGB/EB property does not alter DNA structure and thereby allows reuse of limited DNA samples
Handling and disposal concerns after post staining Potent mutagen and carcinogen Food grade; No disposal issues
Post staining time 10- 20 minutes 1- 10 minutes*

* Depends on the sample and its concentration.

Safety of the Environment and Water is one of the major issues today. Genetic engineering has played a pivotal role in sewage treatment and oil spill clearance. For instance, the clearance of oil spills by genetically modified Pseudomonas putida. Molecular methods that can detect and quantify phylogenetic groups based on rDNA technology have been developed. With the sensitivity of tinto rang™ this issue can be solved, as unlike other available dyes, tinto rang does not intercalate with the DNA / RNA and can detect as little as 0.5 ng of DNA. tinto rang perhaps can be used in the molecular determination of the number of viable microbial cells in the sample.
With the modern techniques like Marker-Assisted Selection/Breeding, scientists can choose the best seeds based on the seed’s DNA and increases the favourable gene action in Crop Breeding. All the molecular techniques like MAS, RNAi & QTLs require the detection of a specific gene / gene-segment associated with a desired trait. By using a more sensitive nucleic acid stain like tinto rang™, visualization after experiments like RFLP, AFLP & RAPD can be made faster, more sensitive & accurate.
Being a Minor Groove Binder / External Binder (MGB/EB), tinto rang™ facilitates the reusability of the genetic material for further studies / applications & also improves cloning efficiency. Traditionally, visualizing the amplified product on an agarose gel used ethidium bromide (EtBr), which was replaced by SYBR Green. However, the implementation of SYBR Green in real-time amplification experiments does not allow discriminating between specific target amplifications and co-produced PCR artefacts, such as non-specific amplifications or primer dimmers. This further interferes with the detection and quantification of the target DNA, especially at low concentrations. tinto rang™ possibly makes better informed decisions about food safety and ingredient authentication.