Easy Proteomics Sample Preparation: Technical Repeatability and Workflow Optimization Across 8 Biological Matrices in...

Bottom-up proteomics relies on efficient and repeatable sample preparation for accurate protein identification and precise quantification. This study evaluates the performance of adapted SPEED (Sample Preparation by Easy Extraction and Digestion) protocol, a simplified, detergent-free approach tailored for various biological matrices, including lysis-resistant samples. Protein extraction and denaturation steps were refined for 8 biological matrices enabling standardized, cheap, and scalable proteomics analysis on 96-well plates. For tissue samples requiring downstream applications like Western blotting, we used a low-detergent RIPA buffer. Notably, the protocols demonstrate remarkable down-scalability, enabling robust proteomics measurements from as few as 3000 cells per sample for preparation and even down to 300 cells per LC-MS/MS analysis. Key advancements include a 30-min nanoLC-MS/MS run, achieving a 15-20 samples-per-day throughput, and leveraging the power of diaPASEF using thoroughly optimized DIA-windows to enhance proteome coverage. These adaptations streamline workflows, enabling proteomics analyses in matrices with challenging physical and biochemical properties. This study underscores the importance of early-stage optimization and feasibility testing in proteomics pipelines to inform study design and sample selection. By showcasing robust, scalable adaptations of the SPEED protocol, we provide a foundation for reproducible, high-throughput proteomic studies across diverse biological contexts.