Pin arrays are tools made up of a set of carefully machined stainless steel pins, with tightly controlled physical dimensions. These arrays are effective at transferring liquid volumes ranging from 10 to 1000 nL. In this volume range, it is difficult for traditional pipettes to maintain accuracy and precision due to the effects of surface tension, wettability, and intermolecular forces of the liquids being pipetted.
Pin tools are preferred for compound transfer at ICCB-Longwood because they conserve reagents and are compatible with the types of assays conducted in the facility. In addition, stainless steel pin arrays are significantly less expensive than a corresponding array of pipet heads and do not require the purchase and disposal of pipet tips.
Compound libraries are stored in DMSO and it is recommended that assays be tested for sensitivity to DMSO up to 1% of the final well volume. The following assay and transfer volumes are recommended to maintain the final compound and DMSO concentrations in the desirable range.
The coefficient of variation (CV) with pin arrays are under 10%, which is acceptable for conducting primary screening of compound libraries. The pin arrays are calibrated to transfer compounds from 384-well ABgene1056 compound storage plates (containing a minimum volume of 7 uL stock solution) into 96- and 384-well assay plates.
To ensure accurate and reproducible pin transfer of compounds to assay plates, the ICCB-Longwood pin arrays are routinely calibrated. Calibration is also performed when new pin arrays are received and when existing pin arrays are refurbished. The calibration protocol uses Rhodamine 110 (rhodamine green) dissolved in DMSO in the source plate (compound stock plate) and PBS in the target plate (assay plate).
The information in the table below assumes a 10 mM compound stock solution (see the compound library page for actual concentrations of each library).
| Pin Array | Volume Transfer Range | Concentration for 30uL Assay |
| Low Volume | 20-40 nL | 6-13 µM |
| Standard Volume | 80-120 nL | 26-40 µM |
| High Volume | 200-300 nL | 33-100 µM |
The table below shows the current volumes and plate types used with the pin arrays at ICCB-Longwood. New plates are routinely added; the following list may not be all-inclusive.
Note: ICCB-L staff test Corning standard and low-volume 384-well microplates, standard 96-well microplates and PerkinElmer Alpha plates for volume transfer precision and accuracy with the pin arrays. All other plate types are approximate volumes transferred.
| Plate Type | Max Plate Volume | Recommended Assay Volume | Standard Pin Transfer Volume(s) |
| Corning 384-well Standard (3704, 3573, 3702, etc.) | 112 µL | 20-30-50 µL | 33, 100, 300 nL |
| Corning 384-well Low Volume (3820, 3824, etc.) | 50 µL | 10-15 µL | 33, 100 nL |
| Greiner 384-well Standard (781101, 781080, etc.) | 131 µL | 20-50 µL | 33, 100, 300 nL |
| BD Falcon 384-well Standard (354666, etc.) | 120 µL | 25-50 µL | 33, 100, 300 nL |
| Nunc 384-well Standard (164688, etc.) | 120 µL | 20-50 µL | 33, 100, 300 nL |
| PerkinElmer AlphaPlate-384 (6005359, etc.) | 105 µL | 20-50 µL | 33, 100, 300 nL |
| PerkinElmer AlphaProxiPlate-384 Shallow Well (6008359, etc.) |
28 µL | 10-20 µL | 100 nL |
| Corning 1536-well Standard (3724, etc.) | 12.8 µL | 5-10 µL | 20 nL |
| Greiner 1536-well Standard (782101, etc.) | 12.6 µL | 5-10 µL | 20 nL |
| PerkinElmer 1536-well Standard (6004660, etc.) | 12 µL | 5-10 µL | 20 nL |
| PerkinElmer AlphaPlate-1536 (6004350) | 12 µL | 10 µL | 20 nL |
| Corning 96-well Microplate (3650, etc.) | 360 µL | 150 µL | 200, 250, 300 nL |
Items in bold indicate our standard plate type, assay volume at transfer, and pin transfer volume used.
