Get the construct right, and everything downstream gets easier.
Independent scientific advisor for AAV, lentiviral and CAR-T programs. I help teams design vectors, plan GMP plasmid supply, build the assays that characterize them, and write the documents that support each phase of development. That includes potency assays for gene-editing therapies delivered by AAV.
Vertex PharmaceuticalsAgilent TechnologiesAllerganInvitrogenMyriad ProteomicsProlexys PharmaceuticalsPhD, University of Reading (UK)Inventor of SureVector
Specialty service
Potency assays for gene-editing therapies
Potency is one of the hardest assays to get right for a gene-editing product, and regulators expect a method that reflects how the therapy works. At Vertex I developed a cell-based potency assay for CRISPR editing delivered by AAV. I help teams heading toward IND plan and build theirs.
Potency assay strategy linked to mechanism of action
Cell model, readout and reference standard selection
Assay development, qualification and phase-appropriate validation plans
Supporting transduction, expression and editing-efficiency assays
Oversight of potency work at CROs, and transfer to QC
Services
Advice at each stage of the construct lifecycle
From the first sequence design to the documents that support a BLA. Engage me for one stage, carry the program through all four, or bring me in to manage the outside labs doing the work.
1 Design
Vector & construct design
Design reviews and strategy that improve cargo stability, expression and manufacturability before you commit to production.
AAV transgene and ITR-containing construct design
Lentiviral and CAR-T vector design analysis
Codon and sequence optimization, including large cDNAs
Helper plasmids and large synthetic assemblies (35–100 kb)
Plasmid backbone and barcode strategies
Non-viral and alternative cargo delivery approaches
CRISPR/Cas editing systems and guide libraries
2 Plasmid
Plasmid & starting-material CMC
Strategy and oversight for the plasmid DNA your AAV or lentiviral process depends on.
GMP plasmid sourcing, CDMO selection and campaign oversight
Master Cell Bank creation and characterization
Manufacturing-grade plasmid specifications and inventory control
Planning for in-house plasmid production capability
Tech transfer from research to manufacturing
Late-stage readiness for plasmid workflows
3 Assays
Analytical & assay development
Characterization and release methods that show your construct and product are what you say they are.
NGS verification of plasmids and AAV particles
Cell-based potency assays, including for AAV-delivered CRISPR editing
Transduction and expression assays
PCR, qPCR and LC-MS methods, including residual host-cell DNA
Characterization and release assay strategy for AAV and CAR-T
Method qualification and transfer to cGMP QC
Multiplex PCR and bioanalytical workflows
4 Documents
Sequence analysis & quality documentation
Clear, traceable documents for every phase of development, from early research through BLA.
Sequence analysis and construct verification reports
SOP authoring and review
Cell bank characterization and release documentation
Assay qualification packages and risk assessments
Drafting and review of regulatory documents, including BLA-stage Type D submissions
Support for deviations, investigations and root-cause analysis
+ Across every stage
CRO & CDMO oversight
Most gene and cell therapy work is outsourced. I have spent much of my career managing CROs and CDMOs, and I help you choose the right partners and keep their work on track.
Scoping work and preparing requests for proposals
Evaluating and selecting CROs and CDMOs
Technical oversight of cloning, plasmid and assay projects
GMP plasmid and cell bank campaigns at CDMOs
Method transfer to and from outside labs
Reviewing vendor data, reports and deviations
Signature innovation
Inventor of SureVector
At Agilent I conceived and drove development of SureVector, a modular DNA assembly system in the same class as Gibson assembly, patented as US 10,662,424 B2, Molecular Fabrication. Standardized, pre-validated parts (origins, selection markers, promoters, your gene) join seamlessly in a single reaction, so a lab can go from vector design to finished plasmid in less than a day instead of weeks.
The same thinking runs through my consulting work. A vector should be built from well-understood parts, assembled so it can be verified, and designed with manufacturing in mind.
1 reactionup to 7 fragments assembled seamlessly
< 1 dayfrom design to finished vector
700,000+possible vector configurations
Used to build pooled CRISPR libraries of 60,000+ guides · Braman & Sheffield, 2019
Modular parts with overlapping ends → one circular plasmid
Track record
By the numbers
20+years in gene cloning, vector construction and gene therapy
2,000+DNA constructs designed and built over my career
5biotech companies advised on vector design and assay development as a consultant
20–30AAV vectors a month delivered by the team I built at Vertex
100 kblargest synthetic assembly: AAV concatemers for stable production cell lines
60,000+guides in the largest CRISPR genome-editing library I developed
2granted US patents, including the SureVector DNA assembly system
30+analytes in a multiplex PCR assay taken from R&D to manufacturing
IND→BLAregulatory documents drafted and reviewed across all phases
About
Meet Peter
Peter Sheffield, PhD · Founder & Principal Consultant
I have spent more than 20 years designing and building DNA for gene therapy and molecular biology, and leading the teams that do it. At Vertex I built and led the vector construction and plasmid production groups for the AAV research program, delivering 20–30 AAV vectors a month, developing a cell-based potency assay for CRISPR gene editing delivered by AAV, establishing NGS methods for vector QC, and managing GMP plasmid campaigns at CDMOs.
Before that I spent nine years directing synthetic biology and CRISPR R&D at Agilent, where I conceived and led development of the patented SureVector DNA assembly system, and my teams built genome-editing libraries of more than 60,000 guides. Earlier, at Allergan, I worked in biologics CMC, developing release assays and writing GMP documentation for early-phase programs. My career started at Invitrogen, Myriad Proteomics and Prolexys Pharmaceuticals, expressing and purifying proteins for X-ray crystallography.
Since 2024 I have worked as a consultant, first with BioRox, advising five biotech companies on AAV and CAR-T vector design and optimization and on characterization and release assays. I founded TCI Consultancy to continue that work and give gene and cell therapy teams direct access to my experience, without the overhead of building it in-house.
Focus
AAV, lentiviral and CAR-T vectors; plasmid CMC; analytics
Prolexys Pharmaceuticals · Myriad Proteomics · Invitrogen· protein expression and purification for X-ray crystallography
Patents
Molecular Fabrication· the SureVector assembly method and kit: pre-made cassettes with hybridizing ends assembled into plasmids in one reaction
Compositions and methods of producing enterokinase in yeast· yeast expression constructs for recombinant enterokinase production (Allergan, granted 2013)
How I work
Three principles
Design for manufacture
A construct that expresses well in the lab but fails in production costs months. I look at stability, size, ITR integrity and plasmid yield from the first design review.
Verify everything
Every construct, plasmid lot and vector should be confirmed by sequence and by function. I help you put the right NGS and potency methods in place early, so data holds up later.
Document as you go
Traceable records from day one make IND and BLA documentation far easier. I help teams build that habit into their SOPs and workflows.
Expertise
Areas of expertise
Modalities
AAV gene therapy
Lentiviral vectors
CAR-T cell therapy
Adenovirus and helper systems
CRISPR/Cas gene editing
Non-viral delivery
Recombinant proteins and biologics
Protein expression and purification for structural biology
Construct engineering
ITR-containing constructs
Codon optimization (e.g. full-length DMD cDNA)
Large DNA assembly (35–100 kb)
Novel plasmid backbones
Barcoding strategies
High-throughput cloning
Analytics
NGS for plasmid and AAV QC
PCR and qPCR, including residual DNA
LC-MS
Cell-based potency (CRISPR via AAV)
Transduction assays
Multiplex PCR (30+ analytes)
Western blot and activity assays
Method qualification
CMC & quality
CRO and CDMO selection and oversight
GMP plasmid manufacture at CDMOs
Master Cell Banks
Tech transfer to manufacturing
SOPs and GMP documentation
Risk assessments
Regulatory documents, IND to BLA
Contact
Let's talk about your program
Tell me where your program is and what's in the way. I reply within one to two business days.