Handheld HDPCG

Payload Description

The Main Purpose of the Handheld HDPCG (High Density Protein Crystal Growth) Experiment is to grow large, well ordered protein crystals in microgravity for highly medically relevant proteins that are difficult to crystallize in 1-g. From these crystals, molecular structures will be obtained and new drugs developed.

Science Objectives

Proteins are important macromolecules without which our bodies would be unable to repair, regulate, or protect themselves. The use of X-ray crystallography to determine protein structure requires the production of well-ordered protein crystals that are of sufficient quality. Without high quality crystals of a protein, it is impossible to carry out crystallographic structural studies. Using three-dimensional structure information, researchers can determine how proteins function and in cases where these proteins are involved in disease processes, the structure is often used to design new drugs that specifically interact with the protein. Many leading drugs today are the product of structure-based drug design. While enormous strides have been made in the last decade, there remain a large number of important proteins where the difficulty of obtaining high-quality crystals is the chief barrier to their structural analysis.

Hardware Overview

Handheld Blocks           Handheld HDPCG Hardware AssemblyThe Hand-Held High Density Protein Crystal Growth hardware is a container that holds five HDPCG sample blocks (called Level III Growth Cell Assemblies) which contain six individual sample wells that provide vapor diffusion crystal growth for a total of 30 sample wells per device. The HDPCG hardware was designed for commonality with typical laboratory vapor diffusion systems. The HDPCG hardware has been successfully used by numerous commercial, government and academic customers on the Space Shuttle and ISS.

HDPCG Blocks              Level III Growth Cell AssembliesThe Level III Growth Cell Assemblies consist of the following parts: a cell body, a barrel, six PPT reservoirs, six access caps, six protein inserts, and six Chromex sponges. The Level III Growth Cell Assemblies provide triple-level containment of the experiment solutions. Each Assembly weights less than 1.0 lbs when filled.


The Handheld HDPCG hardware units can launch in various Cold Stowage facilities. Once on orbit, the units are transferred from these cold stowage locations to an appropriate temperature controlled facility or ambient stowage.