Single-Cell RNA Sequencing Sample Preparation, Library Construction, and Quality Control Workflow

Prepare high-viability single-cell suspensions from tissue or cell samples, perform cell counting, microdroplet or plate-based partitioning, barcoding, library construction, and pre-sequencing quality control.

Experimental Objective

To prepare high-viability single-cell suspensions from tissue or cell samples, perform cell counting, microdroplet or plate-based partitioning, barcoding, library construction, and pre-sequencing quality control.

Scope and Experimental Requirements

  • Sample: Freshly dissociated tissue cells
  • Sample: Cultured cells and primary cells
  • Sample: Peripheral blood or immune cells
  • Sample: Validated cryopreserved cells or nuclei
  • Species: Human, mouse, rat, and other species with high-quality reference annotations
  • Difficulty and Time: Advanced, approximately 2–4 days; sequencing and bioinformatics analysis are extra
  • Safety: Sample collection and processing require appropriate approvals; minimize ex vivo time; partition before and after amplification, and implement RNase, aerosol, and cross-sample control.

Experimental Principle

Individual cells are isolated with a capture system containing cell barcodes and UMIs, allowing transcripts from each cell to be traced after reverse transcription and amplification. After sequencing, cell heterogeneity is deciphered through quality control, dimensionality reduction, clustering, and marker gene analysis.

Standard Workflow

  1. Develop a plan for sample acquisition, transportation, and batch balancing
  2. Gentle dissociation and removal of debris and cell clumps
  3. Assess viability, concentration, and cell size distribution
  4. Calculate loading based on target recovery and perform single-cell partitioning
  5. Reverse transcription, barcoding, and cDNA amplification
  6. Construct gene expression libraries and purify
  7. Perform QC for concentration, fragment distribution, and contamination
  8. After sequencing, perform cell filtering, doublet identification, normalization, clustering, and annotation

Equipment, Reagents, and Consumables

  • Equipment: Biosafety cabinet and refrigerated centrifuge, automated or manual cell counting device, single-cell partitioning platform, PCR cycler, and library QC equipment
  • Reagents: Tissue dissociation and cell preservation reagents, dead cell removal or cell enrichment reagents, single-cell capture and barcoding system, reverse transcription and library amplification reagents, magnetic bead purification and quantification reagents
  • Consumables: Low-binding RNase-free tubes, cell strainers, chips, microfluidic consumables or plates, PCR tubes/plates, and filtered pipette tips

Essential Controls and QC

  • Cell viability and concentration re-verification
  • Blank or cell-free channel
  • Known cell mixture sample
  • Inter-batch reference sample
  • Library negative control
  • Viability and concentration meet platform requirements; cell clumps and debris are controlled; library concentration and fragment distribution are acceptable; effective cell count, genes per cell, UMI, mitochondrial percentage, and doublet rate meet project standards.

Key Parameters and Result Interpretation

Ex vivo time, dissociation strength, viability, cell concentration, doublet rate, ambient RNA, target recovery, amplification cycles, sequencing depth, and batch balancing determine data quality.

Clustering and cell type annotation depend on quality filtering, batch correction, and reference markers. Low-quality cells, stress responses, ambient RNA, and doublets may form spurious subpopulations. Key findings require validation by flow cytometry, imaging, or spatial methods.

Common Issues and Troubleshooting

If viability is low, shorten processing time and optimize dissociation; if cell clumps are abundant, increase filtration and gentle pipetting; if ambient RNA is high, reduce lysed cells and optimize washing; if recovery is inaccurate, recheck counts, concentration, and platform loading parameters.

Product BOM Entry

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Research Use Statement: This workflow is for research experimental design and product selection only; specific parameters, compatibility, specifications, pricing, and delivery are subject to project evaluation and formal quotation.