Molecular hybridization instrument is a core device used for nucleic acid (DNA/RNA) or protein detection in molecular biology research, widely used in fields such as gene expression analysis and mutation detection. Its operation must strictly follow standardized procedures to ensure experimental accuracy. The following is the complete usage process and key points:

1、 Preparation before the experiment

1. Sample and probe preparation

-Extract target nucleic acids (such as genomic DNA and mRNA) according to the experimental purpose, and transfer them to a solid support (nylon membrane/PVDF membrane) after enzymatic digestion and electrophoresis separation.

-Labeling probes: Specific oligonucleotide probes are labeled with isotopes (Ω² P), fluorescent dyes, or biotin, and the purity and concentration of the probes need to be verified.

2. Instrument inspection

-Confirm that the temperature control system of the hybridization instrument is normal, the shaking table function is stable, and the sealing rubber ring is not aged or damaged.

-Preheat the instrument to the set temperature in advance (usually 42-65 ℃, depending on the probe type) to reduce the impact of temperature fluctuations on hybridization efficiency.

3. Reagent configuration

-Prepare pre hybridization solution (containing salmon sperm DNA, SDS and other sealing agents), hybridization solution and gradient salt concentration washing solution, and pay attention to filtration and sterilization to avoid contamination.

2、 Core operational steps

1. Pre hybridization

-Place the membrane fixed with the nucleic acid to be tested into a hybridization tube, add sufficient pre hybridization solution to immerse the membrane, and incubate at the set temperature for 1-2 hours. This step aims to block non-specific binding sites on the membrane and reduce background noise.

-* Key control *: Maintain slight oscillation to promote liquid circulation and avoid bubble formation.

2. Hybrid reaction

-Discard the pre hybridization solution and directly add the hybridization solution containing the labeled probe (the final concentration of the probe is generally 1-10 ng/mL), continue to gently shake and incubate overnight (8-16 hours).

-Optimization strategy: Hybrid temperature=Tm value -5 ℃ (Tm is the probe melting temperature), balancing specificity and sensitivity.

3. Film washing grading

-Use a sequential decreasing salt concentration washing solution (such as sequentially using 2 × SSC → 0.5 × SSC → 0.1 × SSC) for segmented cleaning, gradually removing unbound or mismatched probes.

-* Operation skills *: Before each liquid change, remove any residual liquid. High precision washing can improve specificity, but excessive washing may result in loss of true signal.

3、 Signal detection and data analysis

1. Imaging acquisition

-Select the corresponding detection method based on the probe label type: radioactive self imaging requires X-ray film; Chemiluminescence method using CCD imaging instrument; Fluorescent probes can be directly scanned.

-Exposure Control: Adjust the exposure time to avoid saturation, and synchronously set blank controls to eliminate background interference.

2. Interpretation of Results

-Quantitative analysis was performed using ImageJ software to calculate the grayscale values of the bands, and semi quantitative evaluation of gene expression levels was performed; Qualitative analysis focuses on the consistency between the band position and the expected molecular weight.

-Exception handling: If non-specific bands appear, the probe design needs to be re optimized or the washing rigor needs to be improved.

4、 Aftermath handling and maintenance

1. Waste disposal

-The waste liquid containing isotopes shall be treated according to the radioactive waste regulations, and the fluorescent/chemiluminescence reagents shall be recovered into dedicated containers.

2. Instrument maintenance

-Drain the liquid from the hybridization tube, rinse with clean water, soak in 70% ethanol for disinfection, and calibrate the temperature sensor regularly.

-Record the experimental parameters (temperature, speed, time) and store them in the equipment log for reference in subsequent experiments.

The operation of the molecular hybridization instrument requires precise control of temperature, time, and solution environment, and any deviation in the process may lead to false positive/false negative results. It is recommended that first-time users conduct parallel control experiments and determine the optimal hybridization conditions through preliminary experiments. Standardized operations combined with strict quality control measures are necessary to ensure the reliability of experimental results.