Resuspend the two complimentary strands in a neutral pH buffer. Measure the absorption of the solution using a spectrophotometer and calculate the concentration in moles using the provided extinction coefficient. Mix the two oligonucleotides together in equal molar ratios. Hybridization can be confirmed by running 3 samples on a gel under native conditions. Sample 1: single stranded oligonucleotide 1; Sample 2: single stranded oligonucleotide 2; Sample 3: hybridized oligonucleotide 1 and oligonucleotide 2. If hybridization was successful, the hybridized oligonucleotide Sample 3 lane will run slower compared to the single stranded Samples 1 and 2. If a little of one of the strands is observed in the duplex lane, titrate with the other strand until only duplex is observed. In some cases, it will be necessary to chill the gel to ensure duplex stability.