mPrep/s specimen capsules

mPrep/s™ capsules solve multiple specimen processing challenges.


Less damage. Encapsulated specimens can’t be lost or damaged during processing

Efficient and consistent. Prepare multiple specimens simultaneously and identically

Less handling. Exchange reagents, embed and section for TEM. Exchange reagents and critical point dry or cryo-process for SEM

Precise specimen orientation for TEM and SEM using the mPrep/s Workstation

Accurate reagent delivery with pipettors or the ASP-1000 auto processor can cut consumption by 90%

Experiment in a capsule. Use capsules as microtiter wells to perform experiments and microscopy preparation without removing specimens

Always labeled. Documentation for ISO and GLP standards is easy

Using mPrep/s capsules

1-load unoriented specimen

Load Specimen: Unoriented

  • Insert specimen into capsule
  • Place screen into capsule using the Insertion Tool
  • Rotate Insertion Tool counter-clockwise about 1/8 turn to disengage screen tabs
  • Remove Insertion Tool
2-load pinch oriented specimen

Load specimen: Oriented – Back Pinch Method

  • Press Workstation lever to open slit in mPrep/s screen
  • Insert back end of specimen into opening
  • Release lever to pinch back end of specimen
  • Slide capsule over oriented specimen
  • Rotate capsule counter-clockwise to disengage screen tabs
  • Lift capsule off Workstation
3-load entrap oriented specimen

Load Specimen: Oriented – Entrapment Method

  • Place specimen onto mPrep/s screen in desired orientation
  • Slide capsule over oriented specimen
  • Compress lightly to entrap specimen in desired orientation
  • Rotate capsule counter-clockwise to disengage screen tabs
  • Lift capsule off Workstation
4-attach S capsule to pipettor

Attach Capsule to Pipettor

  • Attach mPrep/f filter coupler to pipettor to protect pipettor from reagents
  • Attach specimen capsule to mPrep/f filter coupler for reagent delivery
  • Capsules can be directly connected to pipettors – not recommended since reagents can damage pipettor
5-prepare simultaneously 8 S on 8-channel

Prepare Multiple Specimens Simultaneously

  • Use multi-channel pipettors
  • No need to use all pipettor channels
6-deliver reagents to S capsules

Deliver Reagents to Capsules

  • Use microwell plates to
    • deliver different reagents to each capsule, or
    • minimize reagent volume
  • Use reagent reservoirs to deliver same reagent to all specimens
7-Transfer S Capsule Cure Resin

Transfer Capsule to Cure Resin

  • Insert resin-filled capsules into mPrep/bench
  • Eject filled capsules from pipettor
  • Remove mPrep/f filter couplers
  • Add more resin to each capsule if larger block is needed
  • Transfer capsules to oven to cure resin
mPrep_G_into grid box-5

Label and Store Capsule

  • Store capsules with cured resin blocks in mPrep capsule grid box
9-Microtome trim S capsule

At the Microtome

  • Clamp capsule into microtome chuck
  • Trim away capsule end to expose block
  • Cut sections from block

Product Description

  • 300 μm holes in capsule bottom and removable adjustable screen
  • Working volume range from 10 to 150 μl
  • Capsules are 19.5 mm long with a specimen entrapping region 9 mm deep by 4.3 mm diameter
  • Highest quality virgin polypropylene suitable for all common EM reagents
  • Autoclave or sterilize like other polypropylene lab ware
  • Sold in packs of 8 mPrep/s capsules with 12 screens in mPrep capsule grid box with included labels
  • Sold as packages of 96 mPrep/s capsules

mPrep s prodsheet

Click to the left to view or download
mPrep/s product description sheet.


An insertion tool is required to insert, remove and adjust the mPrep/s screen. There are two options:

  •  mPrep/s Insertion tool
  •  mPrep/s Workstation (w/integrated insertion tool) enables easy specimen loading and orientation – see Workstation
    • Precisely orient specimens in multiple ways
    • Wet samples easy to handle
    • Use with magnifier or stereo microscope
    • Easy loading of capsules onto pipettors for reagent processing

Pipettor or ASP-1000 automated specimen processor to deliver reagents into capsules

mPrep/f couplers to prevent introducing damaging reagents into pipettors or ASP-1000


mPrep ASP-1000 Automated Specimen Processor for automated specimen and grid processing


Gilson Pipetman Neo (P200) pipettors bundled with mPrep/s capsules for manual reagent delivery

mPrep/s™ Pipettor Kit single-channel

  • Single-channel pipettor
  • mPrep/s capsule pack
  • 96 pipette tips

mPrep/s™ Pipettor Kit eight-channel

  • Eight-channel pipettor
  • mPrep/s capsule pack
  • 96 pipette tips


mPrep/Bench to seal capsule bottoms during long reagent treatments


mPrep CPD holder when using a Tousimis critical point dryer


Reagent reservoirs to hold reagents for delivery of same reagent into 8 or 12 capsules attached to multi-channel pipettor


Microwell plates to hold reagents for delivery of different or same reagents into 8 or 12 capsules attached to multi-channel pipettor

Application Notes

This application note demonstrates the reproducibility of rapid processing with the ASP-1000. Twenty-four (24) specimens from the same aldehyde perfusion fixed liver were prepared for TEM. Specimens were directly handled only once, when they were orientated in mPrep/s capsules. Automated processing required only 133 minutes from post-fix rinse through osmium fixation and 100% resin infiltration. All 24 samples showed well-preserved ultrastructure homogeneity as verified by TEM imaging.

This application note demonstrates using agar embedding of suspended cells to enable rapid automated preparation with the ASP-1000 Automated processor to fix, post-fix and embed cells in epoxy for TEM.  The example uses yeast, but this method can be readily extended to the preparation of other types of cells in suspension, and for the preparation of other small specimens. By combining agar embedment with ASP-1000 processing, 18 centrifugation and resuspension cycles were eliminated from a typical manual protocol. Once the cells were agar embedded, the total processing time prior to epoxy resin curing was just 1.5 hours.

This application note presents a method for processing mammalian muscle tissue for TEM in just over two hours. Using the ASP-1000 automated specimen processor, specimens were processed from postfixation rinse through infiltration in just 133 minutes. Specimens were handled only once, when they were oriented and inserted into mPrep/s capsules using the mPrep/s Workstation.

This application note presents a fast, fully-automated method of tissue processing. Mammalian kidney was prepared for TEM with the mPrep ASP-1000 programmed for highly efficient rapid-agitation. Reagent processing from postfix rinse through 100% resin infiltration was accomplished in just 45 minutes.

This application note illustrates mammalian kidney tissue prep for TEM from fixation through embedding. This general protocol applies to other specimens that require embedding for cross-sectioning. Photos show the mPrep capsule reagent exchange process and how mPrep TEM blocks are faced and sectioned while still in capsules. Supplies and the reagent formulae are listed.

This application note illustrates the preparation of polymer specimens for cross-sectional analysis. Polymer drug delivery particles were embedded and cross-sectioned for transmission FTIR spectroscopy and EDS-SEM. The application note also shows how to extend these methods to the preparation of other soft materials including coatings, thin films and fibers.

List of mPrep/s applications

Tissue processing and orienting specimens for sectioning is time consuming. mPrep/s capsules accurately orient specimens in seconds using the mPrep Workstation. Capsules used with pipettors enable simultaneous and controlled reagent processing.

Processing tissue for SEM can be tedious. There is potential for specimen damage due to contact with labware and critical point dryers. Orienting and mounting brittle CPD prepared tissues is challenging. With mPrep/s capsules specimens are protected and can be oriented prior to CPD processing.

Multiple cryogenic manipulations are required to rapidly freeze and orient tissue specimens for cryo-facing and SEM. With mPrep/s capsules, tissue samples are oriented prior to freezing and secured in the capsule through cryo-facing and SEM mounting.

Embedding and orienting polymers for cross sectioning is challenging: Particles are difficult to entrap and orienting fibers and films is time consuming. With mPrep/s capsules particles are easily entrapped, and fibers or films are oriented in seconds using the mPrep Workstation. Once loaded in mPrep/s capsules, multiple specimens can be simultaneously embedded.


Plumley WC, Kostrna M, Goodman SL (2019) Cryo-Planing Biological Specimens for Scanning Electron Microscopy. Microscopy Today, 27 (2): 20-25. doi:10.1017/S1551929518001451

Cryo-planing (also called cryo-facing) provides a unique 3D view of internal and surface features by cutting a cross-section through frozen tissue or frozen material specimens. Using an mPrep Workstation and mPrep/s capsules, plant and animal tissues were cryo-planed with an ordinary cryo-ultramicrotome, thus using common equipment to provide facile control of the cross-section location. mPrep/s capsules held and oriented specimens throughout all protocol steps: rapid freezing, cryo-planing, freeze-drying, mounting on stubs, conductive coating, and room temperature SEM imaging. This required no custom apparatus or expensive cryo-SEM instrumentation. However, the specimen handling method could be adapted for cryo-transfer and cryo-SEM imaging.

Marques N, Strong J, Strader T, Hsia R-C (2018) Optimization of Automated Immuno EM for Both Pre- and Post-Embedding Labeling. Microsc. Microanal. 24 (Suppl 1), 2018: 1300. doi:10.1017/S1431927618006980

This proceedings paper and poster presents optimized protocols for ASP-1000 automation of immuno-labeling on grids and for en bloc tissues (pre-embedding). On-grid immuno-labeling is shown with sectioned brain, sectioned HeLa cells, and whole-mount bacteria. En bloc tissue immuno-labeling is shown with mouse brain that is also silver enhanced and then resin embedded using the ASP-1000. The authors discuss how automated labeling fits into the lab workflow by providing a “drastic reduction of hands-on time” from several days to 1-2 hours, by enabling overnight processing, and by eliminating manual specimen and grid transfers that can cause sample damage. Also discussed is that automation increased reproducibility and consistently lowered background labeling noise.

Strader TE, Stewart NR, August BK, Goodman SL (2018) Automated Rapid Preparation of Tissue Specimens for TEM Pathology. Microsc. Microanal. 24 (Suppl 1), 201:1284. doi:10.1017/S1431927618006906

This proceedings paper and presented poster shows how the ASP-1000 can accelerate the preparation of TEM pathology tissue specimens from 1-2 days to several hours with conventional chemical reagents. The poster provides automation protocols for the ASP-1000 that accelerate diffusion of processing reagents into specimens by directed fluid flow that is repeated as often as 600 times in just 5 minutes. Examples are provided for multiple tissues including kidney, skeletal muscle, cardiac muscle, liver and brain. The poster also addresses how the automated preparation and mPrep/s specimen capsules and Workstation provide an efficient workflow from specimen acquisition through microtomy that also provides traceability.

Strader TE, Stewart NR, August BK, Goodman SL (2018) A Versatile All-in-One Automated Processor for Electron Microscopy. Microsc. Microanal. 24 (Suppl 1), 2018: 1122. doi:10.1017/S1431927618006098

This proceedings paper presents how the ASP-1000 provides versatility and a workflow solution for research and clinical electron microscopy labs. The authors show the automated preparation of tissues and cell suspensions from laboratory receipt in aldehyde fixative through epoxy and acrylic resin infiltration as quickly as 45.5 minutes for kidney and 2 hours for other tissues. Additional ASP-1000 applications addressed include serial block face SEM specimen preparation, on-grid and en bloc immuno-labeling, and applying gold fiducials to grids for TEM tomography.

Tetri LJ, Diffee GM, Barton GP, Braun RK, Yoder HE, Haraldsdottir K, Eldridge MW, Goss KN (2018) Sex-Specific Skeletal Muscle Fatigability and Decreased Mitochondrial Oxidative Capacity in Adult Rats Exposed to Postnatal Hyperoxia. Front. Physiol. 9. 326. doi:10.3389/fphys.2018.00326

This work used the mPrep ASP-1000 and mPrep/s capsules to prepare rat gastrocnemius muscle for TEM in order to examine mitochondrial ultrastructure in a study that examines postnatal hyperoxia as a model for premature birth effects on aerobic capacity.

McClain M, Nowotarski SH, Zhao Z, Alvarado AS (2017) Rapid Automated en Bloc Staining for SEM of Sections. Microsc. Microanal. PDP-59

McClain and coauthors prepared whole planarian flatworms for serial SEM imaging by developing a rapid automated version of the serial block face SEM protocol developed at the National Center for Microscopy and Imaging Research (NCMIR), which included osmium- thiocarbohydrazide–osmium and lead aspartate staining. With the McClain method, similar results were achieved in just 1.5 days by using rapid automated reagent exchanges with the ASP, compared to 7 days of manual reagent exchanges with the NCMIR protocol. This poster presentation at Microscopy and Microanalysis 2017 also received the 2nd place Diatome Award.

Stewart NR, August BK, Strader TE, Goodman SL (2017) Fast, Walk-away, Automated Processing of Mammalian Tissue for LM and TEM. Microsc. Microanal. PDP-52

Stewart and coauthors demonstrate the automated preparation of kidney, liver, skeletal and cardiac muscle using the mPrep ASP-1000. Reagent processing of kidney was completed in just 45 minutes and liver and muscle in only 2 hours, prior to resin curing. The method provided easy non-messy specimen orientation prior to resin infiltration, and specimens that were only directly handled once - when they were oriented and inserted into labeled mPrep/s capsules.

Stewart NR, August BK, Strader TE, Goodman SL (2017) Preparing LR White Embedded Tissue with mPrep/s Specimen Capsules. Microsc. Microanal. PDP-56

Stewart et al. provides a method for the easy embedding of tissue in LR White resin for TEM immuno-labeling and related applications. The method enables the reliable location of non-osmium treated tissue after embedding, non-messy specimen orientation prior to resin infiltration, minimal specimen handling, and automated reagent processing with the ASP-1000 in less than 45 minutes prior to resin curing.

Goodman SL, Lyden T, Li W-J, Yen T. (2016) 3D Cell Culture and Microscopy in a Capsule with Scaffolds, Tumors & Stem Cells. Microsc. Microanal. 22 (Suppl 3), 2016: 998. doi:10.1017/S1431927616005833

3D cell culture bioreactor systems were assembled with mPrep/s capsules and standard labware. MCF-7 breast cancer cells were cultured for 24 days on 3D collagenous decellularized tissue scaffolds in Prep/s capsules assembled with lab tubing, syringes and pumps. The cancer cells grew into 3D tumor-like structures. Bone marrow derived mesenchymal stem cell pellets were loaded into mPrep/s capsules and grown for 21 days. Pellets grown in mPrep/s bioreactors with continuous flow-through media exhibited a 4-fold increase in the expression of collagen II mRNA, a marker for chondrogensis, in comparison to pellets cultured using mPrep/s capsules as microwell plates.

Lyden T, Cole K, Goodman S (2016) Application of a New Miniature Bioreactor System to Generate and Test Artificial Tumor and Normal Breast Ductal Tissues Using MCF-7/MCF10A Cells. Experimental Biology, W282, 1300.18.

This poster shows using mPrep/s capsules as micro-bioreactors to grow 3-D artificial tumors from MCF-7 breast cancer tumor cells and normal MCF10A breast ductal tissues on biomimetic extracellular matrix substrates. Cells were grown for up to one month into 4 mm diameter by 1 cm long artificial tissues. The “tissues” were characterized with microscopy and western blots. Shed cells from the artificial tissues were collected from media flowing through mPrep/s bioreactors. Flow cytometry showed that the cancer “tumors” shed about 10x more cells with characteristics consistent of metastatic cells.

McClain M. (2016) Bringing Speed and Automation Together with the ASP1000. Microsc. Microanal. 2016. Post deadline poster #49.

McClain developed a TEM tissue fixation and embedding protocol that utilized high speed agitation on the ASP-1000 to prepare planarian worm specimens for resin curing that required only 3 hours. The results were comparable to a 7-day embedding protocol that was previously used to prepare these worm specimens.

Goodman S.L. (2015) Efficient and Documented Preparation of Pharmaceutical Particles for Correlative Microscopy Analyses using mPrep Capsule Processing Microsc. Microanal. 21 (Suppl 3), 2015: 393-4. doi: 10.1017/S1431927615002767

Using mPrep capsules, Goodman prepared two types of pharmaceutical particles for characterization. The mPrep capsules enabled simultaneous and GLP compliant sample preparation. Goodman used mPrep/g capsules to simultaneously prepare 16 grids for TEM from two formulations of siRNA drug delivery nanoparticles with four staining protocols. The grids were then analyzed for morphology and uniformity using TEM. In a separate study he simultaneously embedded four formulations of polymeric drug delivery micro-particles to create eight blocks for cross-sectioning. Thin sections were than analyzed for chemical composition using transmission FTIR and for elemental composition using EDS-SEM.

Goodman SL, Wendt KD, Kostrna MS, Radi C (2015) Capsule-Based Processing and Handling of Electron Microscopy Specimens and Grids. Microscopy Today, 23(5): 30-7. doi:10.1017/S155192951500076

Authors from three institutions prepared animal and plant tissues for TEM. They used mPrep/s capsules for fixation through embedding, and mPrep/g capsules for grid staining. Researches assessed reagent consumption and labor efficiency of mPrep processing compared to traditional processing (using vials, embedding molds and droplet staining). The findings included: mPrep/s specimen processing reduced reagent consumption ten-fold and the number of hands-on operations seven-fold. mPrep/g grid staining reduced hands-on operations six-fold.

McClain M. (2014) High Throughput Multi Parameter TEM Chemical Processing Protocol Development with the mPrep-s Capsule System: Schmidtea mediterranea. Microsc. Microanal. 20 (Suppl 3), 2014: 1288-9.   doi:10.1017/S1431927614008174

McClain simultaneously prepared 16 tissue specimens for TEM using 16 protocols to establish an optimal fixation and embedding protocol. This study varied buffer molarity, en bloc stains, and embedding resins. Reagent processing was conducted simultaneously using multi-channel pipettes and microtiter plates. The author reported, “The mPrep System facilitated the controlled and consistent testing of many conditions, which greatly increased the chances of obtaining optimized specimen preservation in one processing run.”

Strader TE, Goodman SL. (2015) Automated, Programmable Processing of Specimens and Grids with the mPrep ASP-1000. Microsc. Microanal. 21 (Suppl 3), 2015: 11-2. doi: 10.1017/S1431927615000859

Strader and Goodman introduce the mPrep Automated Specimen Processor (ASP), used for simultaneous sample preparation using mPrep capsules. The ASP-1000 prepares TEM and SEM specimens, and stains and labels TEM grids. The paper discusses the ASP-1000 features, including flexibility to efficiently perform routine and complicated tasks. The paper includes pictures of the instrument and examples of heart and skin tissue specimens prepared using mPrep capsule processing.

Plumley WC. (2014) Cryo-Planing of Small Biological Specimens for SEM Using mPrep Capsules. Microsc. Microanal. 20 (Suppl 3), 2014: 1442-3. doi:10.1017/S1431927614008940

Plumley developed a fast and easy cryo-planing method to prepare animal and plant tissues for SEM using the mPrep System. Cryo-planing (also call cryo-facing) provides a unique 3D view of internal and surface features by cutting a cross-section through frozen tissue. Cryo-planing has not been widely used due to the difficulty of handling specimens throughout the tissue preparation process. Plumley used the pinch holding function of mPrep/s screens with modified mPrep/s capsules to hold and orient tissue during this process of rapid freezing, cryo-microtomy, freeze-drying and SEM mounting. He reported that this procedure “enabled easier, faster preparation of multiple small samples, while maintaining the excellent morphology and sectioned view… that cryo-planing is best known for…”

Goodman S. and Kostrna M (2011). Reducing Reagent Consumption and Improving Efficiency of Specimen Fixation and Embedding, Grid Staining and Archiving using mPrep™ Capsule Processing. Microscopy and Microanalysis, 17 (Suppl. 2) , pp 1174-1175. doi:10.1017/S143192761100674X.

This short proceedings paper introduced the mPrep System at Microscopy and Microanalysis 2011. The paper provides an overview of the mPrep System for TEM specimen preparation and TEM grid staining. The System is compared to conventional processing for laboratory efficiency and reagent consumption.


Specimen and Grid Reagent Processing for TEM and SEM

This video tutorial demonstrates how to use mPrep capsules with multi-channel pipettors and common lab ware to simultaneously deliver reagents to multiple specimens and grids. The video demonstrates TEM fixation and embedding. Reagent processing procedures are similar for all specimen types and for grids with mPrep capsules .

6 minutes 4 seconds

Using the mPrep Workstation for Oriented and Unoriented Specimens

The tutorial starts by introducing the mPrep Workstation. Then it demonstrates how to load and orient specimens into mPrep capsules. Three methods are shown: pinch, compression and cup.

5 minutes 19 seconds

Preparing Embedded TEM Specimens for Sectioning

This video tutorial shows how to trim and face an embedded block inside an mPrep/s capsule. The capsule is clamped into a microtome chuck for trimming, facing and sectioning.

1 minutes 17 seconds

Critical Point Dry (CPD) Sample Prep

This tutorial demonstrates how to transfer mPrep capsules to a critical point dryer. The transfer is shown with an mPrep CPD holder designed for the Tousimis Samdri. Both mPrep/s and mPrep/g capsules are shown.

4 minutes 7 seconds

Webinar: TEM & SEM Sample Preparation with mPrep Capsules

This webinar introduces and demonstrates the mPrep System.  Webinar covers how the mPrep System works. It discusses the benefits of the mPrep System over current practice. And it addresses multiple TEM and SEM applications: tissues,  macromolecules, immuno, nanoparticles, cryo-planing.
45 minutes


A single page graphical display of the three steps to insert specimens into mPrep/s capsules using the mPrep/s insertion tool. Use this guide as a lab reference poster.

A single page graphical display of the three steps to orient and load specimens into mPrep/s capsules. Both compression and pinch methods are shown. Use this guide as a lab reference poster.

Instructions for using mPrep/s capsules for specimen handling and processing.

Print this 96-well plate template to organize protocols into columns and rows with a microtiter 96-well plate.

This technical note introduces using mPrep capsule labeling for tracking specimens and grids with a data management system. Topics addressed include mPrep labels, 2D datamatrix barcodes, barcode readers and laboratory information management systems.

How to use the mPrep CPD holder for specimen and grid sample preparation using the critical point method.

Instructions for using the mPrep capsule grid box for storage and labeling of mPrep/g and mPrep/s capsules.

mPrep specimen products

mPrep/s™ Capsule Pack

8 capsules, 12 screens, storage box, labels

Product SKU: 22200


mPrep/s™ Capsules – 96 count

96 capsules, screens & blank label sets

Product SKU: 22500


mPrep/s™ Insertion Tool

Inserts, removes and adjusts screens in mPrep/s capsules

Product SKU: 32010


mPrep/s™ Workstation

Prepare specimens and insert into mPrep/s capsules with or without orientation using integrated screen insertion tool

Product SKU: 42100


mPrep/Bench™ model 96s

96-well silicone rack for mPrep capsules

Product SKU: 34000


mPrep/f 30 Standard Filter Coupler™

16 couplers

Product SKU: 31500


mPrep/f 13 Extreme Filter Coupler™

16 couplers

Product SKU: 31600


mPrep™ CPD Holder

Holds up to 6 mPrep/s or mPrep/g capsules in Tousimis® CPD apparatus

Product SKU: 33010


ASP-1000 mPrep Automatic Specimen Processor

Programable specimen and grid preparation.     Request a Quotation

Product SKU: ASP1000

Reagent Reservoirs

Chemically resistant 15ml reservoirs, 50 per pack

Product SKU: 52001


Microwell Plates

Chemically resistant 96-well plates, 10 per pack

Product SKU: 51001


mPrep/s™ Pipettor Kit eight-channel

eight-channel pipettor, mPrep/s capsule pack, 96 pipette tips

Product SKU: 43250


mPrep/s™ Pipettor Kit single-channel

single-channel pipettor, mPrep/s capsule pack, 96 pipette tips

Product SKU: 43150


For a complete listing of mPrep products, click Purchase.