WORKFLOW KIT · COMPOUND PROFILING

Impermeable Candidate

Validation in Live Cells Kit

Assess cell permeability of drug candidates early, before investing in MedChem

Kits include: Custom cargoes · Optimized protocols · Portal reagents · Delivery cartridges · Suggested readouts

Upgrade Your Workflow

Portal boosts your compound directly into the cytosol, so you can dose the same molecule into boosted and unboosted cells and run the same activity assay in both. Convergent activity means the compound is permeable. Divergent activity, active only after the boost, flags an impermeable molecule: permeability is the issue, not potency. It is a clear early read, before MedChem rather than after.

The Current Workflow is Broken

A compound that looks inactive in cells can be inactive for two very different reasons: it does not bind, or it cannot get in. The two readouts look identical, so you cannot tell a permeability problem from a potency problem. And permeability is usually diagnosed late, after a hit has already gone through MedChem, by which point a dead-end candidate has cost months.

01

Synthesize compound

02

Optimize chemistry

03

Wait weeks, discover issue late

04

Start over

Dead End

Portal has the Solution

01

Prepare

Cells of choice

02

Split

Boosted vs. unboosted

03

Add compound

Same compound to both

04

Measure

Activity in both arms

05

Compare

Divergence vs. convergence

Permeability status, early

~85%

Cell killing from an impermeable inhibitor once it's boosted in, after reading as inactive in intact cells

~80%

Cell killing for the permeable controls, the same with or without the boost

$1M+

Typical spend on biochemical-first hit-to-lead before a compound's activity is ever confirmed in cells. This assay comes first.

What's in the Kit

The cargo and protocols below make this kit specific. The core consumables, settings, and support ship with every Portal kit.

Available Cargoes

You provide: your drug candidate; your cells, primary or cell line
Small molecules, macrocycles, peptides

Don't see your cargo? Ask us about custom configurations

Reagents & Consumables

Saporin positive control
Dextran delivery control
Fluorescent delivery tracer
MicroBooster™
Portal reagents

Protocol & Settings

Dose-comparison wash protocol
Cartridge size and pressure per cell line
Recommended cell concentrations
Suggested activity readouts

Support

Assay setup with a Portal scientist
Optional: hands-on implementation visit

Available Cargoes

You provide: your drug candidate; your cells, primary or cell line
Small molecules, macrocycles, peptides

Don't see your cargo? Ask us about custom configurations

Reagents & Consumables

Saporin positive control
Dextran delivery control
Fluorescent delivery tracer
MicroBooster™
Portal reagents

Protocol & Settings

Dose-comparison wash protocol
Cartridge size and pressure per cell line
Recommended cell concentrations
Suggested activity readouts

Support

Assay setup with a Portal scientist
Optional: hands-on implementation visit

Proof Points

Saporin Only Kills Cells When It's Boosted In

Saporin, an impermeable ribosome-inactivating protein, kills cells only if something carries it across the membrane. Delivered by a boost, it dropped the live population from about 93% to about 16% by Day 3, with most of the remaining cells Annexin V-positive. The same saporin added to unboosted cells left about 93% alive, and boost alone with no saporin left the cells viable.

Kinetics Trace — Boosted vs. Non-Boosted

The same compound dosed into boosted and unboosted cells, read as % signal versus DMSO over a 22-hour time course. In the boosted arm the compound reached its full effect, dropping the signal to near zero within about 12 hours; in the unboosted arm it lagged and plateaued around 55%. Divergence between boosted and non-boosted conditions indicates a compound's permeability status; convergent arms would mean the compound is permeable.

Broad Compatibility

Portal’s platform supports delivery to a diverse range of cell types and cargoes

Delivery materials

Validated cell types

mRNA, siRNA, saRNA

Proteins & Peptides

CRISPR RNPs

Small Molecules

Polymers

Nanoparticles

Antibodies

Virus

PBMCs

T cells

B cells

NK cells

iPSCs

Monocytes

RBCs

HSCs

Delivery materials

mRNA, siRNA, saRNA

Proteins & Peptides

CRISPR RNPs

Small Molecules

Polymers

Nanoparticles

Antibodies

Virus

Validated cell types

PBMCs

T cells

B cells

NK cells

iPSCs

Monocytes

RBCs

HSCs

Check out our other kits

Validated live-cell workflows for target engagement, compound profiling, and beyond.

Every kit includes: Cargoes · Optimized protocols · MicroBooster™ cartridges · Suggested readouts · Reagents

Controllable Surface Antigen Expression

Solves: Fixed, hard-to-modulate surface antigen expression in cell lines
Cargo: Custom antigen/receptor RNA — single or combinations
Express any antigen on any cell in hours
e.g. CD19+CD3, BCMA+CD3, HER2+CD3

Live-Cell Protein Detection

Solves: Live-cell context lost to lysis, and target labeling that requires cell engineering.
Cargo: Intracellular antibodies (primary & secondary)
Measure endogenous intracellular proteins in live cells
e.g. p-BTK, p-ERK, p-AKT, p-STAT3, p-MET Compatible with LgBiT/HgBiT reagents

Live-Cell Target Engagement

Solves: Live-cell context lost to lysis and detergents, and the need to create cell-permeable tracers
Cargoes: Your tracers (e.g. NanoBRET) and compounds
Enables live-cell target engagement without lysis; supports impermeable tracers
e.g. kinase inhibitor profiling, degrader engagement

Intracellular DEL Screening

Solves: DEL screens can't be done in live human cells
Cargo: Your DEL library
Screen intracellular targets with no library bias
e.g. iPSCs, HeLa, PBMCs - any cell type

Direct-to-Assay

Solves: The stable-line bottleneck: infeasible in primary cells, slow and laborious elsewhere
Cargo: Custom RNA encoding tagged POI
Run NanoBRET or LgBiT/HgBiT without stable lines
e.g. VHL-NanoLuc, HgBiT-tagged POI, HA-tagged POI

What is the Impermeable Candidate Validation Kit?The Impermeable Candidate Validation Kit is a Portal Bio workflow kit for finding out, early, whether a drug candidate that looks inactive in cells is failing because it does not bind or because it cannot get across the membrane. You split your cells into two arms, boost the same compound into one arm with Gateway™ mechanoporation, add it to the other arm untouched, and read the same activity assay in both. Convergent activity means the compound gets in on its own; divergent activity, active only after the boost, flags an impermeable molecule. The kit supplies MicroBooster™ cartridges, a saporin positive control, a dextran delivery control, a fluorescent delivery tracer, a dose-comparison protocol, Portal reagents, and an optional hands-on implementation visit; you bring your own compound and cells.

How do you tell a permeability problem from a potency problem?Dose the same compound into two arms of the same cells, one boosted and one not, and compare the activity readout. If the compound is permeable it reaches its target in both arms and the two readouts converge. If it is impermeable it only reaches the target in the boosted arm, so the arms diverge, and that divergence is the permeability signal. Because the boost delivers the molecule directly to the cytosol, a divergent result tells you the binding is real and permeability is the thing to fix, rather than leaving you to guess which of the two is the reason a candidate looks dead.

Why do impermeable compounds show up as false negatives in cell assays?A standard cell assay can only report on a compound that reaches its target, so a molecule with strong target binding but poor membrane permeability reads as inactive, indistinguishable from a compound that does not bind at all. Permeability therefore acts as a gatekeeper: genuinely active chemical matter is discarded as a false negative before anyone confirms it was real. The Impermeable Candidate Validation Kit removes that gate by delivering the compound into the cytosol with Gateway™ mechanoporation, so activity can be evaluated independently of permeability and a false negative is caught early instead of after medicinal chemistry.

Can I assess compound permeability before medicinal chemistry optimization?Yes, that is the point of the kit. Permeability is usually diagnosed late, after a hit has already gone through medicinal chemistry, by which time a dead-end candidate has cost months. A biochemical-first hit-to-lead campaign runs about a year and $1M or more before activity is confirmed in cells, and peptide permeability optimization adds roughly 12 to 18 months. Boosting the compound into cells gives a clear read on whether permeability is the problem in a single side-by-side experiment, so permeability can be treated as an engineering task to solve rather than a biological unknown, before that investment is made.

What kinds of compounds and cells can I test with this kit?The kit is built for the impermeable and partially permeable modalities that conventional cell assays struggle with: small molecules, macrocyclic and linear peptides, PROTACs and molecular glues, kinase inhibitors, and chemical probes. Because Gateway™ mechanoporation is a physical delivery step and does not depend on a cell being transfectable, it works in the cells you actually care about, primary cells as well as established lines. You dose your compound as it is; there is no need to design a permeable analogue or build a special cell line first.

Has this been validated with real drug-discovery compounds?Yes. In a pharma partner's small-molecule screen, permeable control compounds killed about 80% of cells with or without the boost, confirming that boosting does not change the activity of a compound that already gets in. A series of impermeable compounds were completely inactive in intact cells but showed activity once delivered, and one recovered about 85% cell killing after the boost, previously undetectable potency that would have been discarded as a false negative. Portal has also boosted impermeable macrocyclic peptides into HEK293 cells to about 80% delivery with viability maintained, showing the same boosted-versus-unboosted read across compound classes.

Ready to run the Controllable Surface Antigen Expression Kit?

Request the kit and a Portal scientist will spec it for your cells, cargo, and readout.