BioBricks answers

Every answer below is aimed at a question people measurably search for, is written from named sources, and links to the page that handles the job itself. None of them is a landing page in disguise.

Answers for the lab that orders synthesis and sequencing: what OEM oligos, guide RNA, sgRNA, antisense oligonucleotides and custom DNA synthesis are and how each is priced; how plasmids are constructed, purified and produced at scale and what the certificate has to show; and what an amplicon sequencing service should deliver per sample. Each page points at the vendor comparison on this site that records the prices vendors actually publish, verified and dated.

• OEM oligos: how bulk and private-label oligo supply is quoted, and what to ask before you sign

  What OEM oligos are, how a kit maker or diagnostics company gets them quoted, and the specification questions that set the price per base.

• Guide RNA for CRISPR: single guide, crRNA and tracrRNA, synthetic or in vitro transcribed, and how each is priced

  How to choose and buy guide RNA for CRISPR: sgRNA or two-part guides, synthetic or in vitro transcribed, chemical modifications and what each costs.

• Oligonucleotide synthesis: how custom oligos are made, why scale and purification set the price, and how to compare vendors

  How oligonucleotide synthesis works, why price per base depends on scale, purification and modifications, and how to compare vendors.

• sgRNA: what a single guide RNA is, when to buy it synthetic, when to make it, and how vendors price it

  What sgRNA is, how a single guide differs from a two-part guide, when to buy it synthetic and when to transcribe it, and how vendors price it.

• Large scale plasmid production: research, high quality and GMP grades, what each certificate covers and how to buy

  How large scale plasmid production is graded from research to GMP, what the certificate must show, how lead time scales and how to compare vendors.

• shRNA: how short hairpin RNA knockdown works, plasmid versus lentiviral versus library formats, and how to buy the constructs

  What shRNA is and how it differs from siRNA, the plasmid, lentiviral and library formats it is sold in, and where the plasmid price comparison fits.

• Antisense oligonucleotides: the chemistries, the purification and testing they need, and how research-use synthesis is priced

  How antisense oligonucleotides are made for research use, why modified chemistries drive cost, what testing to require and how to compare vendors.

• Plasmid construction: how a custom plasmid is built from synthetic DNA or cloning, what verification to require and how the service is priced

  What a plasmid construction service does, when synthetic DNA replaces cloning, the verification to require and how gene synthesis vendors price it.

• Amplicon sequencing: targeted PCR sequencing for microbiome, variant and editing readouts, and how services price it

  What amplicon sequencing is, its 16S, variant and CRISPR editing uses, what a service should deliver and how to compare sequencing vendors on price.

• Custom DNA synthesis: which product to order for which job, and how each is priced per base

  The three tiers of custom DNA synthesis, oligos, gene fragments and cloned genes, what each is for, how price per base is set and how to compare vendors.

• Order oligos: the choices on the order form, what each costs, and how to pick a vendor on published price and lead time

  How to order oligos: scale, purification, modifications and delivery format, what each choice does to the price, and how to compare vendors first.

• Plasmid purification: how plasmid DNA is prepared and graded, what the purity figures mean, and when to send it to a service

  How plasmid purification works from miniprep to large scale, what purity, supercoiling and endotoxin figures mean, and when to use a service.

• The best laboratory information management system, read vendor by vendor

  Five LIMS products read on 11 September 2026: LabWare, LabVantage, Sapio, Benchling and LabLynx. Not one of the five publishes a price on its own site.

• The best pipettes for a working bench, read manufacturer by manufacturer

  Three pipette ranges read on 11 September 2026. Eppendorf lists $575.31 for a Research plus 2-20 uL single channel; Sartorius routes to a shop instead.

• The best electronic lab notebook software, read vendor by vendor: what each of four ELN products leads with on its own page, where the notebook stops and a platform begins, and why none of them will quote you a price

  Four ELN products read on 12 September 2026: Benchling, SciNote, SciSure and Labguru. None publishes a figure; all four route to a demo.

• The best confocal microscope for your samples, read vendor by vendor: what four confocal platforms lead with on their own pages, why point scanning and spinning disc answer different questions, and what none of the pages will tell you about price

  Four confocal platforms read on 12 September 2026: ZEISS LSM, Leica STELLARIS, Nikon AX with NSPARC and Andor Dragonfly. None publishes a price.

• The best mass spectrometer is the one that matches your question: five vendor ranges read vendor by vendor, why quantitation and identification pull toward different analysers, and what none of the pages will tell you about price

  Five mass spectrometry ranges read on 12 September 2026: Thermo Orbitrap, Bruker timsTOF, Agilent LC/MS, SCIEX and Waters. None publishes a price.

• Automated cell isolation: what a closed instrument changes about yield, purity and hands-on time

  What an automated cell isolation instrument changes about purity, yield and hands-on time, and what to make a vendor demonstrate on your own material.

• Fresh leukopak: how an apheresis collection is specified, shipped and priced

  What a fresh leukopak is, how donor and collection specification set the price, and what has to arrive with the cells for the material to be usable.

• Human biospecimens: what a research supplier has to be able to evidence

  What to demand from a human biospecimen supplier: consent and ethics paperwork, annotation, handling history and the evidence that makes a sample usable.

• T7 RNA polymerase: what the grades differ on, and how suppliers price the enzyme

  What T7 RNA polymerase does, what a unit measures, how research and GMP grades differ, and what decides the price of the enzyme at scale.

• AAV ELISA: what a capsid titre kit measures, and where it disagrees with genome titre

  What an AAV ELISA measures, why capsid and genome titre disagree, how serotype limits kit choice, and how to validate a kit on your process.

• Laboratory asset management: what the software tracks that an inventory system does not

  How laboratory asset management differs from reagent inventory, why calibration and service history is the reason to buy, and what to specify.

• HEK 293 HCP ELISA kit: how a host cell protein assay is matched to the cell line and the process

  How a host cell protein ELISA is matched to the cell line and the process, why platform and process-specific kits differ, and what coverage shows.

• HPLC equipment: what a working system needs beyond the pump and the detector

  What HPLC equipment a working system needs beyond the pump and detector, what the quote leaves out, and where the running cost actually sits.

• Protein characterization: which methods prove identity, purity, size and activity

  Which protein characterization methods prove identity, purity, size, higher order structure and activity, and which order to buy them in.

• Protein quantification: choosing the assay, and the standard that decides the answer

  How protein quantification assays differ, why the standard decides the number, and which assay survives detergent and color.

• T4 DNA ligase: what a unit means, which buffer to use, and how suppliers price it

  What a T4 DNA ligase unit means, why two suppliers' units are not comparable, which buffer and temperature to use, and what decides the price.

• Bioconjugation: choosing the chemistry, controlling the ratio and proving what you made

  How bioconjugation chemistries differ, why the substitution ratio is the specification, and what analysis proves a conjugate is what the order asked for.

• Immune cell markers: what a lineage panel actually needs

  Which markers define B, T, NK, dendritic and plasma cells, why one marker is never enough, and why some populations are defined by what they lack.

• qPCR master mix: what is in the tube and when to mix your own

  What a qPCR master mix contains, why the concentrate is sold at 2x, how one-step and two-step reverse transcription differ, and where variance comes from.

• Western blot transfer buffer, and the other buffers a blot run needs

  What goes in a transfer buffer and why methanol is in it, plus the tank, stripping, wash and antibody dilution buffers a blot needs.

• Automated ELISA, and what the workstation actually replaces

  What an automated ELISA platform adds beyond the plate reader, where the washer decides the result, and when multiplexing is the cheaper answer.

• Pyruvate assay kit, and what every enzyme-coupled metabolite kit shares

  What is actually in a metabolite assay kit, which interferences ruin it, why deproteinising matters, and when the classical method is still better.

• Chem lab equipment, and how much the discipline really changes the list

  The core equipment almost every laboratory buys, and the four places where the discipline genuinely changes the specification rather than the list.

• HaCaT cell line, and what a designation does and does not tell you

  What the common named lines are actually models of, which ones are not cell lines at all, and the identity and maturity traps behind each designation.

• GC MS analysis, what it costs and what a used instrument changes

  What a GC-MS quotation includes and leaves out, why the vials and septa matter more than expected, and what to check before buying a used instrument.

• Bioreactor for cell culture, and what stops working as the volume grows

  What a bioreactor changes about a culture, why adherent expansion is the hard case, and which bench habits do not survive the move to volume.

• HPLC test, and what the result does and does not prove

  What an HPLC result actually establishes, what a quotation covers, and when sending samples out beats running the separation yourself.

• Fab antibody, and when the whole molecule is the wrong reagent

  What a Fab is, why removing the constant region fixes background and blocking, and how digested and recombinant fragments differ in practice.

• Protein A resin, and the three numbers that decide which one to buy

  What dynamic capacity, cleaning tolerance and ligand leaching mean in practice, and how the affinity resins differ from one another.

• 293T cells, and why almost every vector is packaged in them

  What the T in 293T does, why it makes the line the default packaging host, and what actually decides titre and particle quality.

• LIMS providers, and what separates a shortlist from a long list

  How to compare LIMS vendors on the four answers that decide the project: what you may configure, who configures it, what support covers, who validates.

• Pharmaceutical LIMS, and the validation work a license does not cover

  The same software as any LIMS with a different burden of proof: what a regulated lab must evidence, who does that work, and what an inspector reads.

• HPLC instrument quotations, and the modules that decide what you can run

  An HPLC is a set of modules, not a product. What each one fixes about the methods you can run, and what a quotation leaves you to buy later.

• Custom mRNA orders, and the five things the quotation turns on

  What a custom mRNA order specifies beyond the sequence: capping, untranslated regions, tail, modified bases and purification, and who should make it.

• Myeloid markers, and which of them survive the preparation

  Which markers separate neutrophils, monocytes, macrophages, dendritic cells and microglia, and which of them move with activation or with handling.

• T cell activation markers, and the order in which they appear

  Which activation markers appear in hours and which in days, what they mean beside proliferation, and how the equivalents on B, NK and NKT cells differ.

• Lysosome marker antibody choices, and the compartment set beside it

  Which antibodies mark each compartment, what they report when the compartment changes, and why a colocalisation result depends on the fixation.

• CD markers flow cytometry panels are built from, lineage by lineage

  What the CD numbering does and does not tell you, and the marker sets that identify T, B, NK, dendritic and granulocyte populations in practice.

• Histone antibody choices, and what the modification claim rests on

  Why histone antibodies are the hardest specificity claim in the catalog, what a datasheet has to show, and how the naming of the same target differs.

• Cell counting instruments, and what each of them is actually counting

  Brightfield, fluorescence and impedance counters measure different things. What each counts, where viability comes from, and what still needs a chamber.

• Knockout cell lines, and the evidence a clone owes before it is used

  What separates an edited pool from a knockout clone, which evidence a certificate should carry, and where a knock in or a stable Cas9 host changes it.

• Continuous manufacturing, and the unit operations where it pays first

  Which steps genuinely gain from running continuously, what it costs in control and analytics, and where a batch step is still the cheaper answer.

• CRISPR plasmids, and which format the experiment actually needs

  All in one against separate vectors, what a kit contains, where interference and screening differ, and which plasmid a hard to transfect cell wants.

• Thermal analysis equipment, and which technique answers your question

  What each thermal technique measures, which one a formulation question needs, and why the pan and the calibration matter more than the brand.

• Liquid dispensing systems, and where dispensing stops and handling begins

  A dispenser fills plates from bulk; a handler moves samples between them. Which a workflow needs, what a quote leaves out, where used equipment fits.

• LB agar plates, and the variables that decide whether they behave

  What a poured plate is specifying beyond the recipe: the formulation you chose, antibiotic handling, drying, storage and why plates drift between batches.

• ORF clones, and what a catalog entry actually guarantees

  What an open reading frame clone is verified against, which isoform and tag you are getting, and when synthesis or a library is the better route.

• Colony picking robots, and the throughput at which one pays

  What an automated picker does well, the imaging and pin decisions that decide pick accuracy, and the plate counts below which a person is cheaper.

• hcDNA, and what a residual host cell DNA result actually bounds

  What the assay measures, why size matters as much as quantity, which method suits which process, and what a specification is really controlling.

• tff filtration, and how a crossflow step is sized

  Cassettes against hollow fibres, membrane area and flux, what UFDF means, and the questions that decide a crossflow purchase.

• synthetic genes, and what an order actually specifies

  Sequence, codon usage, the vector it arrives in, what a supplier guarantees, and where synthesis beats cloning from a template.

• An electroporator, and choosing one for the cells you have

  Square wave against exponential decay, cuvettes and cartridges, what a protocol is really specifying, and where chemical methods are better.

• sem eds, and what the elemental result actually reports

  How the spectrometer works with the column, what standardless quantification means, spot against map, and where the method stops.

• An lcms machine, and the configuration that decides its price

  Which analyser to buy, what the chromatograph in front contributes, where the running costs sit, and how a quote is read module by module.

• A chromatography skid, and what it has to do at scale

  Flow range and pressure, valve and sensor count, single use paths, buffer preparation, and what a process skid has to record.

• An antibody labeling kit, and what to check before you use one

  Chemistry by site, the buffer the antibody has to be in, degree of labeling, and when a conjugation service is the better purchase.

• cleanroom environmental monitoring, and what a program has to hold

  Viable and non-viable sampling, where the sites come from, what the grades ask for, trending, and the excursion procedure behind the data.

• A single use assembly, and how one is specified

  What a pre-sterilised assembly contains, the components it is built from, the documents it arrives with, and where stainless still wins.

• A capsule filter, and how one is sized

  Self-contained cartridges against a housing, membrane and rating, how area is sized from a flow decay test, and what integrity testing proves.

• A bfp antibody, and the reporter tag antibodies beside it

  What an antibody against a fluorescent protein is for, cross reactivity between the variants, and how each reporter is best detected.

• A detection antibody, and how it is paired and labeled

  Matched pairs for a sandwich assay, secondary antibody choice by host and label, and where a conjugate beats an indirect stack.

• A cofilin antibody, and the cytoskeletal and adhesion antibodies beside it

  What to check on antibodies against actin regulators, focal adhesion proteins, junctions, matrix and adhesion receptors, and which controls they serve.

• A smyd3 antibody, and the chromatin, repair and cell cycle antibodies beside it

  What to check on antibodies against chromatin enzymes, damage response proteins, nuclear receptors and apoptosis regulators, application by application.

• An irf5 antibody, and the immune and inflammation antibodies beside it

  What to check on antibodies against myeloid and lymphoid markers, pattern recognition receptors, nucleic acid sensors, cytokines and checkpoints.

• A ferroportin antibody, and the transporter, receptor and enzyme antibodies beside it

  What to check on antibodies against multipass transporters, hepatic receptors, G protein coupled receptors and metabolic enzymes.

• A tyrosine hydroxylase antibody, and the neural and retinal antibodies beside it

  What to check on antibodies against neurotransmitter enzymes, synaptic and myelin proteins, lineage factors, retinal markers and transporters.

• An lc3 antibody, and the autophagy, mitosis and stress antibodies beside it

  How a flux readout differs from an abundance one, and what to check on antibodies against autophagy, mitotic, stress and damage targets.

• An endoglin antibody, and the vascular, stromal and tumour surface antibodies beside it

  What to check on antibodies against vascular and lymphatic markers, stromal activation antigens, matrix proteins and tumour surface targets.

• An apoe antibody, and the plasma protein and biomarker antibodies beside it

  What to check on antibodies against abundant plasma proteins, acute phase markers, complement components and bone and autoimmune antigens.

• A btk antibody, and the kinase and receptor antibodies beside it

  What to check on antibodies against kinases, growth factor and cytokine receptors, and mechanosensitive channels, and why phospho clones need controls.

• A hemagglutinin antibody, and the infection and restriction antibodies beside it

  What to check on antibodies against viral surface proteins, entry receptors, endotoxin, interferon-induced restriction factors and myeloid sensors.

• A ductless fume hood for lab work, and the enclosures beside it

  Filtered against ducted, liner material by chemistry, benchtop and canopy forms, and why a laminar flow bench is not a fume hood at all.

• used liquid handlers, and buying second hand laboratory equipment generally

  What to check on a used deck, imaging and inspection equipment, plate readers, cryostats and chromatography systems, and where support ends.

• Sterilization equipment, and the laboratory kit it sits among

  Choosing a sterilisation method by load, what laboratory sterilizers cover, and how the rest of a laboratory's equipment list is grouped by job.

• A twist1 antibody, and the transcription factor and ligand antibodies beside it

  What to check on antibodies against developmental transcription factors, AP-1 and nuclear receptor family members, and secreted Wnt ligands.

• A giantin antibody, and the organelle and trafficking antibodies beside it

  What to check on antibodies used as compartment markers, from Golgi and cilia to mitochondria, the nuclear envelope and stress granules.

• A trispecific antibody, and the format and reagent questions beside it

  What a three-armed format has to solve, how developability is assessed, conjugates that degrade a target, and the reagents an assay needs.

• A p40 antibody, and the tissue marker antibodies beside it

  What to check on markers read in tissue: squamous and epithelial antigens, mucins, junction and matrix proteins, and the controls a panel needs.

• A cdk4 antibody, and the cycle, replication and repair antibodies beside it

  Reading cell cycle and DNA repair antibodies as states rather than amounts, and what each needs as a positive control and a sample.

• A cd8 antibody, and the immune surface and cytokine antibodies beside it

  What to check on lymphocyte and checkpoint markers, adhesion molecules, stromal markers and the cytokines measured beside them.

• A cyp1a1 antibody, and the metabolic, transporter and redox antibodies beside it

  What to check on antibodies against drug metabolising enzymes, membrane transporters, respiratory subunits and redox proteins.

• An il-8 antibody, and the cytokine and receptor antibodies beside it

  What to check on antibodies against interleukins measured in medium and the chemokine and lineage receptors read on the surface.

• A snap25 antibody, and the synaptic and developmental antibodies beside it

  What to check on antibodies against synaptic proteins, neurotrophin receptors, motor neuron and progenitor factors, cilia and mitotic scaffolds.

• A sumo antibody, and the modification and adaptor antibodies beside it

  What to check on antibodies against modifiers and ligase machinery, death and innate adaptors, autophagy proteins and repair complexes.

• An acta2 antibody, and the actin, collagen and junction antibodies beside it

  What to check on antibodies against smooth muscle actin, collagen chains, motor and adhesion proteins, and epithelial keratins.

• A rat antibody, and what a catalog name actually tells you

  Host against target, model antigens, anti-PEG reagents, fully human formats, biotinylation kits and how to search a catalog without guessing.

• A hif 1 alpha antibody, and the stress and lineage factor antibodies beside it

  What to check on antibodies against oxygen and oxidative stress factors, interferon and cytokine signalling nodes, and developmental regulators.

• A kras g12d antibody, and the mutation and clinical marker antibodies beside it

  What a mutation-specific clone has to prove, and what to check on repair, epigenetic, immune and iron handling markers read in tissue.

• Buying pipets, and the tips, controllers and verification around them

  What decides a pipette purchase: volume range against the work, single or multichannel, the tip that seals on it, and how often accuracy is checked.

• Ordering a myostatin inhibitor peptide, and the peptides and proteins beside it

  What a peptide or protein listing has to state: sequence, purity and its method, salt form, and the assay an activity figure came from.

• Choosing an exosome isolation kit, and what has to be measured afterwards

  What each isolation chemistry recovers, why a kit alone does not prove a vesicle, the markers and the serum a vesicle experiment needs.

• Choosing a mycoplasma test kit, and the contamination testing around it

  How the detection methods differ, what a negative result covers, and where bioburden and microbiological testing sit beside routine culture screening.

• Buying a microwave digester, and the sample preparation equipment beside it

  What a closed vessel digestion buys, how homogenisers and pulverisers differ, and the balances and glassware the weighing step depends on.

• A p20 pipette, and the repeaters, controllers and checks around it

  Which volume range to buy, where a repeater or a motorised instrument earns its cost, and how accuracy is verified between calibrations.

• aav antibodies, the serotypes they recognize, and how a vector is measured

  Which capsid an antibody sees, how serotypes differ, what a titre assay counts, and where a recombinant vector's measurement can mislead.

• A large volume pipette, the smaller ranges, and the tips each one takes

  Which range covers which work, what changes above a millilitre, and how tip type, orifice and material decide whether a transfer is accurate.

• The types of liquid chromatography, and the detector each separation needs

  How the modes differ, when gas chromatography is the right instrument instead, and what each detector can and cannot see.

• A 1 ml pipette, the electric and positive pressure alternatives, and the accessories

  Which instrument covers a millilitre, where electronic and positive displacement models earn their cost, and what the tip material and reservoir change.

• A cbs antibody, and the metabolic enzyme antibodies read beside it

  What an enzyme antibody can and cannot report, and what to check on the amino acid, lipid and nucleotide pathway enzymes read as expression markers.

• A tyk2 antibody, and the kinase and signalling antibodies read beside it

  Why a total kinase blot is only a denominator, which residue a phospho clone must name, and the controls that make a pathway claim.

• A foxo1 antibody, and the transcription factor antibodies beside it

  Why a nuclear extract and a loading reference matter, how family members defeat a conserved clone, and when location rather than level is the readout.

• A 1000 ul multichannel pipette, the repeat and positive pressure models, and the accessories

  Where a large volume multichannel is worth having, how repeat and positive displacement instruments differ, and which accessories change a result.

• A myosin heavy chain antibody, and the isoform and modification antibodies beside it

  Why an isoform specific clone is the whole question in muscle work, and what to check on modification, viral and receptor antibodies read the same way.

• Buying cell culture products: the water, the plates, the buffers and the models

  Which consumables change a result rather than a cost, what the plate format decides, and what each common model system can and cannot answer.

• A viral titer assay, and the vector, editing and model tools around it

  What each titre method counts, how a neutralisation assay differs, and what the common vector, driver and editing tools actually provide.

• The molm13 cell line, and the tumour models bought beside it

  What each line models, the mutation or receptor status that makes it the standard choice, and the authentication every one of them needs.

• A binocular compound microscope, the specialist instruments, and the cameras

  What separates a compound instrument from a stereo one, which specialist microscopes exist and why, and what a camera adds or costs.

• Buying glass lab beakers, and the flasks, racks and holders around them

  Which glassware class a measurement needs, what each vessel is actually for, and the holders and brushes that keep them usable.

• A cold centrifuge, the rotor types, and the formats each one takes

  What refrigeration is for, how the rotor decides the separation, and which instrument reaches the force a protocol names.

• pipette tips 1000ul, the ranges they serve, and the accessories around them

  Which tip serves which instrument, what the surface and the filter change, and which accessories protect the pipette and the sample.

• chromatography solvent grades, the columns they run on, and method transfers

  Which solvent grade a detector demands, what each column chemistry is for, and how a method moves between column formats.

• A biosafety cabinet class 2 a2, the other classes, and what a fume hood does instead

  What each cabinet class protects, where a fume hood is the right answer instead, and what a used cabinet has to prove.

• A retort autoclave, the cycle types, and the formats a laboratory actually buys

  What separates an industrial retort from a laboratory autoclave, which cycle a liquid load needs, and what the chamber and door decide.

• hollow fiber filters, the perfusion they enable, and the dialysis formats beside them

  What a hollow fibre module does, how perfusion and seed intensification use it, and where a dialysis device is the right format.

• A pbs reagent, the buffers beside it, and what a grade actually certifies

  What separates a buffer grade from a formulation, which buffers a protocol names, and what a substrate or a ladder has to state.

• A multi channel pipette 1000ul, and the larger single volumes beside it

  Why a multichannel at the top of the range is rare, which format serves millilitre transfers, and what a tip has to certify.

• chemical lab equipment, the storage around it, and the furniture it sits on

  How a chemistry bench is equipped, what storage the chemistry dictates, and where industrial and metallurgical kit differs.

• gas chromatography testing, and choosing the contract laboratory that runs it

  What accreditation to ask for, which laboratory type runs which test, and what a report has to carry to be usable.

• An lkb1 antibody, the kinases it sits above, and reading a phosphorylation

  What an antibody against a kinase can and cannot report, which readout means activity, and how a dilution is chosen.

• A fancd2 antibody, and the targets where validation is the whole difficulty

  Which targets have few usable clones, what control proves each one, and when a section needs fluorescence instead of chromogen.

• sw480, the lines it is compared against, and what each panel is for

  Which line answers which question, what authentication each needs, and why a panel beats a single line.

• An e0771 cell line, the spellings it appears under, and the mouse lines beside it

  Which mouse lines run in an immunocompetent host, what the strain match means, and what a primary culture cannot be bought as.

• A 1ml volumetric flask, the cylinders beside it, and what each one measures to

  Which vessel measures to what tolerance, why a small flask is the hardest to read, and what a plastic cylinder gives up.

• cell therapy bags, the process around them, and who manufactures it

  What a single-use bag has to prove, where a process range is found, and what a cell therapy CDMO is chosen on.

• seamless cloning, and the scarless assembly methods behind the name

  What the method is, which chemistries produce no scar, and when a restriction digest is still the better route.