Welcome to Midland Certified,Your Source for Oligonucleotides,DNA, RNA, LNA and Polynucleotides!


Midland has been a leader in the synthesis of DNA and RNA oligonucleotides for over 35 years. We pioneered the use of MAL:DI-TOF mass spectrometry for quality assurance of oligonucleotides, a technique that has become the gold standard for the industry. Guided by our commitment to quality we have designed and built DNA synthesizers which produce oligonucleotides of higher sequence fidelity than any instruments commercially available today.

Midland oligos are often used for gene synthesis in the following way. Two sets of 40-mers are synthesized, each set comprising one of the two strands of the desired gene. Each oligo overlaps a 20-base region of two oligos in the complementary set. The oligos are all combined in approximately equal amounts and several cycles of amplification by PCR are performed. Finally two oligos corresponding to the 5’-ends of each of the strands are added and several more cycles of PCR are run. The products are purified by electrophoresis and the product of the desired size is collected.

The process is used for example in the technique called genetic immunization (De-chu Tang, Michael DeVit & Stephen A. Johnston, NATURE 536, 152-154 (1992)). A synthetic gene is coated onto gold microspheres and introduced into a small animal with a gene gun. The animal produces antibodies to the protein encoded by the synthesized gene. This obviates the need to purify the antigenic protein.

Another outgrowth of our focus on the quality of our synthesis chemistry is the ability to modify oligonucleotides. Today we offer more than 200 modifications, including fluorophores, quenchers, backbone modifications, degeneracies, and minor nucleotides. To view the complete alphabetical listing, click here. While several modifications can be ordered directly from this website, many pose technical challenges that we will need to discuss with you before we proceed to manufacture. Evidence of success in the modification is provided by the printout of the MALDI-TOF mass spectrum of every modified oligonucleotide.

We continue to offer all of the popular purification modalities, such as HPLC and PAGE purification. However, synthesis technology has advanced sufficiently that for many applications purification that was essential a few years ago is no longer necessary.Thus, for example, genes are constructed with GF grade (desalted) oligonucleotides without the need for further purification.

We continue to offer a wide range of polynucleotides, including duplexed polynucleotides and template/primer combinations. Click for lists of DNA Polynucleotides, RNA Polynucleotides, or Template/Primers used to distinguish reverse transcriptase from DNA polymerase activities.

We also sell and offer information on such popular products such as: