mPrep/s Workstation

mPrep/s™ Workstation efficiently loads and orients specimens into mPrep/s capsules.  Use for TEM and SEM.


Accurate orientation. Specimens may be oriented using several methods

Efficient workflow. Streamlines specimen processing from dissection to reagent processing

Reduce handling. Once loaded in capsules, specimens are not touched again for TEM embedding or SEM mounting

Easy dissection. Single focal plane keep specimens in focus during dissection and when loading specimens in capsules

Wet samples. Dissect and load specimens wetted by buffers or fixatives

Efficient reagent processing. Directly load capsules onto pipettor from Workstation

Organized for efficient workflow

Product Description

  • Durable, corrosion-resistant materials for long service with saline, buffers and aldehyde fixatives. Can be fully immersed for cleaning.  Safe cleaning with detergents, bleach and alcohol
  • Top cutting surface is:
    • Soft high density polyethylene (HDPE) that minimizes dulling of fine dissection tools
    • Low glare and lightly textured surface for optimal visibility and easy specimen handling
    • Top is easily replaced if it becomes marred with cuts after long use
  • 6 dissection wells to organize and prepare specimens, and keep them wet
  • 12 capsule wells and screen storage in back holds 12 capsules until used
  • 24 capsule wells (12 per side) to hold mPrep/s capsules after loading with specimens and to keep them wet. Spaced for direct attachment of capsules onto 8 and 12-channel pipettors
  • Rounded front edge provides comfortable use
  • Feet adjust to change height. Adjust for comfort and to straddle many dissecting microscope bases
  • Precision mechanism is fully adjustable.

Using the mPrep Workstation


Prepare the specimen

  • Trim and dissect on Workstation surface
  • Use shallow wells to keep specimens organized
  • Add water or fixative to wells during dissection

Load screen (and unoriented specimens)

  • Insert mPrep/s screen into Workstation insertion tool
  • Engage screen tabs into insertion tool flanges

Orient specimen – Back Pinch Method

  • Press Workstation lever to open screen
  • Place back end of specimen into screen opening
  • Release lever to pinch specimen

Encapsulate specimen

  • Slide capsule down to hold specimen in place
  • For Back Pinch Orientation method leave space above specimen

Remove capsule from Workstation

  • Rotate capsule counter-clockwise to disengage screen from Workstation insertion tool
  • Lift capsule off Workstation

Set aside encapsulated specimen

  • Place capsule into a Workstation well
  • Add fluids to wells to keep specimens wet
  • Load capsules directly onto pipettor for reagent processing

Application Notes

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.

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 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 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 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 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.

mPrep workstation applications

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.

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.

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.


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

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


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

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

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.

mPrep/s workstation 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™ Workstation

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

Product SKU: 42100


mPrep/f 30 Standard Filter Coupler™

16 couplers

Product SKU: 31500


For a complete listing of mPrep products, click Purchase.