Chapter Four · failure evidence
What Transient Transfection got wrong, from 62 dissertations
The records demonstrate that transient transfection methods frequently fail due to low delivery efficiency in primary cells, severe reagent toxicity, and high expression variability across experimental replicates. Furthermore, novel physical delivery devices and engineered nanoparticle formulations repeatedly underperform established commercial reagents and electroporation protocols. These records come from PhD theses at 20 institutions, 2021 to 2026. Each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Standard chemical transfection suffers from low efficiency in primary and recalcitrant cells
Lipid and chemical transfection reagents consistently failed to achieve adequate target gene expression or knockdown in primary fibroblasts, myometrial cells, macrophages, and neurons. As a consequence, researchers were repeatedly forced to replace transient chemical methods with viral transduction vectors or specialized electroporation.
Considered and rejected
Considered and rejected: Transient transfection with plasmid DNA was rejected/abandoned in favor of in vitro transcribed mRNA transfection after struggling for over a year to introduce genes into the model cell line.
SARS-CoV-2 targets NKG2D ligands to evade natural killer cell-mediated immunity · Harvard
Considered and rejected
Considered and rejected: Rejected transient transfection for expressing catalytically dead SMG1 due to low transfection efficiency (4–6% BFP-positive cells) and inability to rescue expression.
Protein Degradation Pathways Associated with Nonsense-Mediated mRNA Decay · Harvard
Considered and rejected
Considered and rejected: Co-transfection of eGFP-Rab33b variants with mCherry-LC3B (or eGFP-LC3B with mCherry-Rab33b) in U-2 OS cells was rejected due to low transfection efficiency and weak mCherry fluorescence intensity.
Towards a molecular understanding of the role of Rab33B in hereditary skeletal dysplasia · Research Repository UCD
Tried and failed
lipid- and polymer-based chemical transfection applied to monocytic cell lines. Outcome: worse than baseline. Reason: ineffective transfection efficiency compared to specialized cationic nanoparticle reagent
The mode of action and role of cGMP-mediated gene transcription in macrophages · Imperial
Tried and failed
lipid-based chemical transfection applied to primary human cardiac fibroblasts. Reason: yielded extremely low transfection efficiency of less than 5 percent in primary cells
The role of small open reading frames in myocardial fibrosis and genetic disease · Imperial
Tried and failed
electroporation-based plasmid transfection for gene reconstitution applied to knockout myeloid cell lines. Outcome: no signal. Reason: failed to achieve adequate expression levels compared to lentiviral transduction
The role of EROS in T cell biology · Imperial
Considered and rejected
Considered and rejected: Rejected conventional lipofectamine plasmid transfection for mature neurons due to very poor efficiency (<2.5% GFP+ cells), switching to rAAV viral delivery.
Optimizing RNA therapies for dementia and their delivery to disease models · IRIS - UNITN - prod
Considered and rejected
Considered and rejected: Rejected standard Lipofectamine 2000 transfection for astrocytes due to poor transfection efficiency, switching to nucleofection and lentivirus instead
MicroRNA and Nrf2 pathway manipulation in human astrocytes: towards a therapeutic approach for Amyotrophic Lateral Sclerosis (ALS) · University of Nottingham Repository
Considered and rejected
Considered and rejected: Rejected standard lipid transfection reagents (TransIT-LT1, jetPRIME, TransFectin) in primary myometrial cells in favour of adenoviral infection due to poor sensor expression and localization efficiency
Myometrial cyclic AMP function · Imperial
Considered and rejected
Considered and rejected: Rejected standard Lipofectamine 3000 transient transfection for KLHL41 in C2C12 cells due to very low expression, opting instead for retroviral transduction.
Deciphering the roles of Kelch-like proteins · Iowa State
Considered and rejected
Considered and rejected: Lipid nanoparticles and electroporation for VSMC transfection (rejected due to low transfection efficiency; replaced with AAV2 serotype delivery).
The role of vascular smooth muscle Sirtuin-1 in aortic aneurysms · OpenBU
Considered and rejected
Considered and rejected: Rejected lentiviral and plasmid/mRNA transfection methods for primary macrophages due to macrophage DNAse activity and low transfection efficiency.
Considered and rejected
Considered and rejected: Rejected direct chemical/lipid transfection of foregut monolayers due to cell packing and low (<10%) transfection efficiency in favour of stable inducible AAVS1 targeting in hiPSCs.
Deciphering the role of BMP4 signalling and gene regulation in the specification of human liver progenitor cells · University of Nottingham Repository
Tried and failed
non-liposomal chemical transfection of siRNA applied to primary and immortalised myometrial cells. Outcome: no signal. Reason: failed to achieve reliable, effective target gene knockdown compared to electroporation
Novel nanoparticle formulations and uncomplexed nucleic acids fail to match standard transfection reagents
Experimental delivery vehicles such as PEGylated nanocomplexes, chitosan polymers, and naked nucleic acids frequently yielded negligible translation or gene editing due to particle entrapment and uptake inhibition. When tested against established benchmarks like Lipofectamine, these non-viral formulations produced substantially lower expression and editing rates.
Lost to a baseline
In vitro transfection in HepG2 cells showed PBAE 546 was significantly less effective than PBAE 447, despite 546 performing best for liver transfection in vivo.
Engineered Therapeutic Plasmids and Nanoparticle Delivery Vehicles for Targeted Treatment of Hepatocellular Carcinoma · JScholarship
Lost to a baseline
Sub-100 nm FNC nanoparticles achieved only 1/100 of the transfection yield of conventional manual pipet-mixed pDNA/PEI batches.
BOTTOM-UP ASSEMBLY OF SHELF-STABLE SUBMICRON DNA PARTICLES FOR MANUFACTURING OF LENTIVIRAL VECTORS · JScholarship
Lost to a baseline
In vitro mRNA delivery with chitosan-IAA nanoparticles showed negligible GFP transfection compared to the Lipofectamine control.
Utilizing Combinatory Adjuvant-Loaded Chitosan-Derived Nanoparticles for a Joint SARS-CoV-2/Influenza Vaccine · Georgia Tech
Tried and failed
permanently charged cationic lipid substitution in nanoparticles applied to RNA delivery formulations. Outcome: worse than baseline. Reason: produced significantly lower transfection expression compared to degradable ionizable lipid benchmarks
Development of Chemically-Defined Platform Materials for Localized Delivery of RNA Therapeutics · MIT
Lost to a baseline
K-NDs exhibited suboptimal transfection efficiency compared to Lipofectamine control due to endo-lysosomal entrapment.
Lost to a baseline
Lipofectamine pegRNA transfection positive control achieved 19.2% editing efficiency compared to 0.5% for the best engineered nanoparticle variant (v3s_T_TFRmb/v3s_T_scpH192).
Computational design of de novo protein nanoparticles for RNA delivery · ResearchWorks
Tried and failed
direct transfection of naked mRNA applied to epithelial cell lines. Outcome: no signal. Reason: naked mRNA transfection yielded negligible translation compared to vector-formulated delivery across cell types
Investigating the potential of modified messenger RNA for epithelial repair in the lung · Imperial
Tried and failed
imidazole-functionalized chitosan nanoparticle delivery applied to in vitro mRNA transfection. Outcome: no signal. Reason: nanoparticles failed to transfect mRNA into mammalian cells compared to standard lipid transfection reagents
Utilizing Combinatory Adjuvant-Loaded Chitosan-Derived Nanoparticles for a Joint SARS-CoV-2/Influenza Vaccine · Georgia Tech
Tried and failed
PEGylation of cationic lipid and polymer nanoparticles applied to in vitro dendritic cell mRNA transfection. Outcome: worse than baseline. Reason: PEGylation severely reduced or abolished cellular uptake and mRNA transfection efficiency
Mesoporous Silica Rods Scaffolds for the generation of adaptive immune responses · Harvard
Lost to a baseline
Lipofectamine 3000 achieved higher transfection in HEK293 cells compared to PEGylated chitosan nanocomplexes (which suffered from PEG shielding effects)
Development of non-viral systems for pulmonary nucleic acid delivery and gene editing · UT Austin
Lost to a baseline
Lipofectamine 3000 achieved robust in vitro eGFP transfection whereas Alginate-b-PEG-b-PLA nanoparticles showed zero expression even at 4X mRNA dose.
Polymer mosaics for modulation of hydrogel structure · OpenBU
Lost to a baseline
GalNAc-mediated naked transfection yielded 0% indel formation compared to 17–27% indel frequency achieved by lipofectamine CRISPRMAX
Bioconjugation strategies for oligonucleotide functionalisation · Oxford
Lost to a baseline
AAV2/9-PHP-B positive control showed robust and consistent hair cell transduction whereas PBAE (100 nm) showed inconsistent transfection and hair bundle damage
DEVELOPING TOOLS TO TARGET COCHLEAR HAIR CELLS · JScholarship
Transfection reagents and delivery protocols cause severe cytotoxicity and loss of cell viability
Increasing plasmid concentrations, omitting protective coatings on polycationic vehicles, and applying harsh delivery methods triggered substantial apoptotic cell death across multiple cell lines. The resulting cytotoxicity and membrane damage compromised experimental cultures and forced investigators to discontinue transient delivery.
Considered and rejected
Considered and rejected: Rejected physical transfection methods (microinjection, electroporation, magnetoporation, laser-mediated transfection, biolistic particle delivery) for hiPSC-CMs due to poor cell viability, cytotoxicity, disruption of excitable membrane ion fluxes, and low throughput
Linking molecular targets to hypertrophic cardiomyopathy using genome-edited human induced pluripotent stem cell cardiomyocytes · University of Nottingham Repository
Tried and failed
electroporation of miniature CRISPR plasmid vectors applied to primary fibroblast cells. Outcome: no signal. Reason: severe electroporation-induced cytotoxicity and undetectable plasmid transfection or reporter gene disruption
AAV TRANSDUCTION TRACING IN HEMATOPOIETIC CELLS BY TARGETED SCARRING OF GENOMIC SAFE HARBORS · Harvard
Tried and failed
increasing plasmid DNA concentration during transfection applied to reporter expression in mammalian cells. Reason: higher DNA concentrations caused transfection-induced apoptotic cytotoxicity, reducing reporter expression
Measuring Apoptotic Sensitivity Through Oligonucleotide Mediated Peptide Delivery · Harvard
Tried and failed
polycationic nanoparticles lacking hydrophilic stealth coating applied to in vitro nucleic acid delivery. Outcome: worse than baseline. Reason: absence of PEG shielding caused severe cytotoxicity at low concentrations compared to standard transfection reagent
Polycationic nanoparticles for microRNA delivery in neuroblastoma · UT Austin
Tried and failed
Lipid-based siRNA transfection applied to suspension cell culture. Reason: reagent toxicity caused complete cell death even at reduced siRNA concentrations
Lost to a baseline
Lipofectamine 2000 showed slightly higher transfection efficiency in VX2 cells compared to lipopolyplexes, but exhibited significantly higher cytotoxicity.
Knockdown of CRPV E6 and E7 Oncogenes Using Lipopolyplexes as Transfecting Reagents Knockdown of CRPV E6 and E7 Oncogenes Using Lipopolyplexes as Transfecting Reagents · open_UMR Marburg DSpace 10.0
Considered and rejected
Considered and rejected: Lipid-based transfection reagents for BHK-21 cells were replaced by electroporation due to low transfection efficiency and transfection-induced cytotoxicity.
Novel Cas orthologs from natural reservoirs and design of a directed evolution approach in mammalian cells to enhance their editing potential · IRIS - UNITN - prod
Considered and rejected
Considered and rejected: Rejected PEI-mediated transfection and electroporation for organoid CRISPR delivery due to extreme toxicity and <1% survival efficiency, adopting lentiviral transduction instead.
Genetic screens in intestinal organoid (mini-gut) culture using CRISPR-Cas-9 System and studying the role of FBXL5 in colorectal cancer cells · University of Nottingham Repository
Considered and rejected
Considered and rejected: Rejected lipid/liposome-based transfection (e.g., FuGENE, Lipofectamine) for delivering CRISPR components into HUVECs due to high cytotoxicity, cytoplasmic nucleic acid degradation, and low efficiency compared to electroporation.
Dynamics of cytokine induced E-selectin expression in endothelial cells · University of Nottingham Repository
Considered and rejected
Considered and rejected: Rejected electroporation for AAVS1 gene targeting due to cell toxicity, using lipid transfection (X-tremeGENE9) instead.
Considered and rejected
Considered and rejected: Transient PEI transfection for long-term (>6 hr) or chronic drug treatments was discontinued due to transfection reagent-induced cytotoxicity after 72 hours.
MAPPING AND SPATIAL MONITORING OF THE DNA DAMAGE SIGNALING NETWORK USING MASS SPECTROMETRY · Cornell
Transient transfection causes expression heterogeneity and replicate variability compared to stable cell lines
High levels of inter-cell expression noise, copy-number variation, and transient loss of expression undermined experimental reproducibility across repeated assays. Investigators systematically abandoned transient plasmid delivery in favor of stable lentiviral transduction or targeted genomic integration to secure durable phenotypic responses.
Lost to a baseline
Transient cDNA transfection of NMDARs in HEK cells achieved a lower recording success rate (34.1%, 28/82) compared to stably expressing GABA_A receptor cell lines (60.8%, 31/51, p = 0.0039).
Towards automation of multimodal cellular electrophysiology · Georgia Tech
Considered and rejected
Considered and rejected: Rejected relying solely on transient transfections for efflux and viability assays due to confounding variation between experimental replicates, choosing stable lentiviral infections instead.
Regulation of manganese efflux transporter SLC30A10 for maintaining manganese homeostasis · UT Austin
Considered and rejected
Considered and rejected: Transient transfection was rejected in favor of stable lentiviral transduction due to cell-line longevity requirements.
A bump and hole approach to the development of selective degrons · Oxford
Considered and rejected
Considered and rejected: Rejected transient transfection/transduction for in vitro differentiation assays due to phenotypic variability from low efficiency; adopted stable G418 selection and clonal isolation instead
Long noncoding RNA Meg3 regulates myoblast plasticity and skeletal muscle regeneration · OpenBU
Considered and rejected
Considered and rejected: Rejected transient transfection with C3H10T1/2 cells in 384-well format due to high Hill slopes and transfection variability, moving to stably expressing Shh-Light2 cells
Considered and rejected
Considered and rejected: Abandoned transient transfection and mixed stable populations for CASE-Gs assays due to undetectable dynamic range
The molecular basis of Gs protein efficacy at the b2- adrenoceptor · University of Nottingham Repository
Considered and rejected
Considered and rejected: Rejected transient transfection of HEK-Blue cells with GCN4-TIR plasmids due to construct-independent cell death and inconsistent signaling, switching to stable Flp-In T-REx HEK-293 cell lines with inducible expression
Investigating the Structure-Function Relationships Between Flagellins and Toll-Like Receptor 5 · Publikationssystem UB Tuebingen
Considered and rejected
Considered and rejected: Avoided transient transfection for locus proteomics due to inter-cell expression heterogeneity.
Advancing Locus-specific Chromatin Isolation Methods for Multi-omic Discoveries · ResearchWorks
Considered and rejected
Considered and rejected: Rejected transient transfection for large-scale Fzd production due to low yield (~60% efficiency) and costly DNA requirements, switching to inducible lentiviral stable cell lines.
Considered and rejected
Considered and rejected: Rejected transient transfection and lentiviral reporter delivery in favor of CRISPR Cas9-mediated targeted genomic integration at AAVS1 to avoid copy-number noise across large pools.
A Nascent Peptide Code for Translational Control of mRNA Stability in Human Cells · ResearchWorks
Specialized microfluidic and physical delivery platforms fail to outperform conventional transfection baselines
Novel microfluidic constriction channels, nanoneedle arrays, and piezoelectric dispensers struggled to achieve uniform delivery across heterogeneous cell populations. These experimental physical delivery systems achieved lower transfection efficiencies and viability than conventional electroporation cuvettes or flat surface controls.
Lost to a baseline
Convective microfluidic transfection of large multicistronic CRISPR/Cas9 plasmids into iPSCs performed no better than standard Lipofectamine Stem (<1% efficiency).
Microfluidic Cell Processing for Personalized and Regenerative Medicine · Georgia Tech
Lost to a baseline
ZsGreen plasmid transfection on-chip with 0.5 ms PW yielded 0% efficiency compared to 7% transfection on conventional Eppendorf cuvette electroporation
EXPANDING VORTEX TRAPPING AND ELECTROPORATION CAPABILITIES TO SMALL CELLS · JScholarship
Lost to a baseline
Polymer substrate laser-based transfection achieved only up to 20% efficiency for 150 kDa dextrans and 9% for siRNA with ~60% viability, performing worse than gold nanoparticles or plasmonic pyramids.
Visualization and manipulation of repair and regeneration in biological systems using light · Leibniz Universität Hannover Repository
Lost to a baseline
pGFP transfection efficiency using 20 μm and 30 μm piezoelectric heads reached only ~1.0-1.1%, severely underperforming Neon NxT electroporation which achieved 78.8%.
Lost to a baseline
Flat surface-mediated transfection of mEPDCs yielded higher net efficiencies than nanoneedles (nN)
Genetic enhancement of epicardial paracrine signalling for cardiac regeneration · Imperial
Tried and failed
convective microfluidic constriction cell transfection applied to large plasmid delivery to iPSCs. Outcome: worse than baseline. Reason: substantial cell size heterogeneity prevented uniform mechanical constriction and membrane permeabilization
Microfluidic Cell Processing for Personalized and Regenerative Medicine · Georgia Tech
Lipid nanoparticles and chemical reagents underperform electroporation in challenging cell types
Lipid-based formulations and commercial liposomal reagents achieved substantially lower delivery percentages than electroporation in human T cells, cardiac fibroblasts, and pituitary cell lines. Investigators found that electric field delivery provided superior transfection rates in these cell types despite the convenience of chemical alternatives.
Lost to a baseline
Lipid nanoparticles (LNPs) achieved only 20.56% transfection efficiency in PCFs compared to 52.24% with electroporation.
Etablierung eines optogenetischen Systems zur lichtinduzierten Proteinbiosynthese in humane Stammzellen für therapeutische Anwendungen · Leibniz Universität Hannover Repository
Lost to a baseline
Electroporation yielded slightly higher transfection percentage in primary human T cells than B10 LNPs
Ionizable lipid nanoparticles for mRNA CAR T cell engineering · Penn
Lost to a baseline
Liposomal transfection reagent Lipofectamine 2000 yielded lower transfection efficiency compared to electroporation in GH4C1 cells
Understanding somatic activating ESR1 mutation's role in the tumorigenesis of prolactinomas · OpenBU
Left open by the authors
Problems the authors named and did not get to.
Left open
Predict the behavior of chromosomally integrated genetic systems directly using transient poly-transfection or co-transfection data. Blocker: Requires experimental wet lab generation of paired transient transfection and chromosomally integrated cell line data.
Left open
Assess mRNA transcript stability across time points post-transfection using RT-qPCR. Blocker: Requires a wet lab, cell culture, transfection protocols, and RT-qPCR equipment and reagents
Investigating the potential of modified messenger RNA for epithelial repair in the lung · Imperial
Left open
Transition ProKAS from transient transfection to stable genomic integration across various cancer and untransformed cell lines to extend assay duration. Blocker: Requires wet-lab molecular biology facilities, cell culture, and genomic engineering tools.
MAPPING AND SPATIAL MONITORING OF THE DNA DAMAGE SIGNALING NETWORK USING MASS SPECTROMETRY · Cornell
Left open
Optimize transfection and electroporation protocols to establish a functional dTAG system for FOXA1 in cell lines like HEK293T. Blocker: Requires a wet biology lab, cell culture facilities, and transfection/lentiviral reagents.
Toward High-throughput, Quantitative Platforms to Identify the Targets of Small Molecules · MIT
Left open
Implement and validate a four-plasmid transfection strategy to decouple Rep and VP expression in viral vector manufacturing. Blocker: Requires wet lab facilities for plasmid transfection, cell culture, and viral vector yield quantification.
Left open
Test whether TFEB silencing or RagC (S75L) overexpression suppresses proliferation in breast cancer cell lines. Blocker: Requires a wet lab, cell cultures (breast cancer cell lines), and lentiviral transfection experiments
Silencing TFEB Suppresses Mammary Gland Acini Development and Proliferation · UT Austin
Left open
Test alternative mtDNA direct transfection strategies with 100 µg/ml CAP concentration and a two-month selection period. Blocker: Requires wet-lab experiments with cell culture, mtDNA transfection, and chemical selection
Left open
Develop a protocol to eliminate or reduce the two pre-transfection and transfection-day centrifugation steps for large-scale CHO cell cultures (>20 L). Blocker: Requires access to a wet-lab cell culture facility and bioreactors for large-scale mammalian cell cultivation.
Left open
Optimize the transient CHO antibody production workflow parameters to shorten the culture process duration from 14 days to 11 days. Blocker: Requires a wet biology lab, CHO4Tx cell lines, transfection reagents, and automated protein purification equipment.
Left open
Optimize cell selection and culture conditions to increase recombinant Lubricin-Inspired Product yield from 0.01 g/L toward typical antibody titers. Blocker: Requires wet-lab mammalian cell culture facilities, transfection reagents, and protein quantification assays.
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