Best Practice for Nucleic Acid Thermal Stability Measurements Using the Cary 3500 UV-Vis Spectrophotometer - Thermal melt (Tm) analysis using rapid, precise temperature-dependent UV-Vis absorbance measurements
UV-Vis spectrophotometers have been used widely for nucleic acid quantification and quality control (QC) utilizing the fact that nucleic acids have a maximum absorbance at 260 nm (1). The concentration of nucleic acids can be easily estimated using the absorbance at 260 nm and the established absorption coefficient. Often a background correction is also performed, for example collecting a baseline using a solution containing everything but the nucleic acid or by measuring the absorbance at a wavelength that nucleic acids do not absorb. Double stranded nucleic acids are bound by hydrogen bonds between the base pairs. The temperature at which double stranded nucleic acids denature to become single stranded depends on the: – sequence and length of the nucleic acid – the pH and buffer conditions – and any mismatches in base pairs between the two strands As such, the melting temperature is very useful analytical tool and can be studied by monitoring the absorbance at 260 nm as temperature is increased or decreased. As the temperature is increased, the hydrogen bonds between the strands are broken and the double stranded nucleic acid separates into two
Mastering Antibody-Drug Conjugates: BIOVECTRA's Approach to ADC and Complex Chemistry Manufacturing
December 19th 2024BioPharm International sat down with Jean-François Vincent-Rocan, Director of Complex Chemistry Process Development at BIOVECTRA, to discuss antibody-drug conjugate (ADC) manufacturing. Due to their complex manufacture and supply chain management, JF emphasizes the need for a company that greatly understands the challenges and offers solutions that maintain quality and reliability. He also mentions what advancements are to come in this field and how best to stay ahead of a rapidly growing treatment option.
Harnessing mRNA as a Readout to Develop Robust BioPotency Assays
December 12th 2024Transcriptional activity within a cell can be used to evaluate cell response to a ligand or promoter activity within a transgene or plasmid within a cell. Catalent has developed a relative potency bioassay using real-time quantitative reverse transcription (RT-qPCR) in a duplex format to assess relative transcription activity in cells treated with ligands or transgenic vectors. The assay utilizes two fluorescent dyes with minimally overlapping emission spectra that allow real-time monitoring of the gene expression of both target and normalizer genes. The assay does not require purification of the mRNA produced by the cells once lysis has occurred. Normalizing the qPCR cycle thresholds (CT) of the target transcript to the reference transcript allows response curve to be generated and compared to a reference standard. The generation of a four-parameter fit curve analysis from raw qPCR cycle threshold data allows for comparison of relative potency and assessment of suitability based on curve parallelism. The assay platform has been used by Catalent to qualify a repeatable, accurate, linear, and specific bioassay for assessing relative potency.
