Biotechnology Engineering

PCR (Polymerase Chain Reaction) amplifies DNA templates using primers and Taq polymerase through denaturation, annealing, and extension cycles. RT-PCR (Reverse Transcription PCR) first converts RNA to cDNA using reverse transcriptase, then amplifies it via PCR. RT-PCR is essential for gene expression studies and RNA virus detection (like COVID-19 testing). Real-time/Quantitative PCR (qPCR) monitors amplification in real-time using fluorescent probes (TaqMan) or dyes (SYBR Green) for quantification.

Upstream processing includes all steps before and during fermentation: media preparation, sterilization, inoculum development, and the fermentation/cell culture process itself. Downstream processing covers post-fermentation steps: cell harvesting, cell disruption (for intracellular products), clarification, chromatography purification, concentration, formulation, and fill-finish. Downstream typically accounts for 50-80% of production costs due to purification complexity and regulatory requirements for biologics purity.

CRISPR-Cas9 is a revolutionary genome editing tool derived from bacterial adaptive immunity. A guide RNA (gRNA) directs the Cas9 nuclease to specific genomic locations, creating double-strand breaks. The cell repairs these via NHEJ (causing knockouts) or HDR (precise edits with donor template). Applications include: gene therapy (sickle cell, muscular dystrophy), crop improvement, disease model creation, drug target validation, and CAR-T cell engineering. It is faster, cheaper, and more precise than ZFNs and TALENs.

Good Manufacturing Practice (GMP) is a system ensuring products are consistently produced according to quality standards. Key elements include: qualified personnel, validated processes, controlled environment (cleanrooms), proper documentation (batch records), equipment calibration, raw material qualification, and deviation management. GMP compliance is mandatory for regulatory approvals (FDA, EMA, CDSCO) and prevents contamination, cross-contamination, mix-ups, and ensures product efficacy, safety, and patient protection.

ELISA (Enzyme-Linked Immunosorbent Assay) detects antigens or antibodies using enzyme-conjugated antibodies that produce measurable color when substrate is added. Types include: Direct ELISA - antigen coated, enzyme-labeled primary antibody; Indirect ELISA - antigen coated, unlabeled primary, enzyme-labeled secondary antibody; Sandwich ELISA - capture antibody, antigen, then detection antibody (highest specificity); Competitive ELISA - sample antigen competes with labeled antigen. Sandwich ELISA is widely used in diagnostics for its high specificity and sensitivity.