DNA, RNA, and Protein Extraction: The Past and The Present

Abstract

Extraction of DNA, RNA, and protein is the basic method used in molecular biology. These biomolecules can be isolated from any biological material for subsequent downstream processes, analytical, or preparative purposes. In the past, the process of extraction and purification of nucleic acids used to be complicated, time-consuming, labor-intensive, and limited in terms of overall throughput. Currently, there are many specialized methods that can be used to extract pure biomolecules, such as solution-based and column-based protocols. Manual method has certainly come a long way over time with various commercial offerings which included complete kits containing most of the components needed to isolate nucleic acid, but most of them require repeated centrifugation steps, followed by removal of supernatants depending on the type of specimen and additional mechanical treatment. Automated systems designed for medium-to-large laboratories have grown in demand over recent years. It is an alternative to labor-intensive manual methods. The technology should allow a high throughput of samples; the yield, purity, reproducibility, and scalability of the biomolecules as well as the speed, accuracy, and reliability of the assay should be maximal, while minimizing the risk of cross-contamination.

mirRICH, a simple method to enrich the small RNA fraction from over-dried RNA pellets

“…Therefore, chaotropic reagents like ethanol are required to disrupt salt-nucleic acid complex thereby salts are selectively solubilized into water [3]. In addition, it is difficult to isolate pure RNA, DNA and protein due to interphase contamination [4]. …”

“…The principle of hydrophilic and hydrophobic interaction is utilized in this selective elution of nucleic acid with chaotropic agents such as ethanol. Contents of solid phase is usually filled with glass particle, silica, diatomaceous and anion-exchange dependent of specific usage [4]. Possibly, other components of cells such as protein also can bind to column.…”

“…Possibly, other components of cells such as protein also can bind to column. Thus, it is required to perform washing procedure to remove these contaminants by adding their competitive molecules [4]. …”

“…Recently, silica or cellulose coated magnetic beads are applied to capturing either DNA or RNA in acidic 4M guanidinium thiocyanate [4,9,10]. This method is used for quick isolation of nucleic acid within 30min in the purpose of detection of viral infection [9].…”

“…In addition, magnetic oligo (dT) bead is applied to purify RNA species having poly(A) tail of mRNAs. This method selectively purifies only mRNAs among total contents of RNAs because magnetic beads conjugated with poly(dT) oligo-nucleotide can interact with poly(A) tails of mRNAs [4,11]. However, cost of magnetic beads are relatively expensive than traditional RNA extraction technology.…”