MALDI plate spotting solutions at Innovadyne Technologies

Accurate MALDI plate spotting is a critical success factor in MALDI-TOF mass spectrometry, where compounds must be spotted on a flat, metal MALDI target plate. Positional accuracy and precise deposition of the spots is critical. Classical liquid handlers using contact methods are prone to failure due to plate and tip irregularities and poor positional accuracy (typically > 100 µm/axis). Innovadyne’s platforms reliably fulfill critical MALDI spotting requirements with precisely manufactured motion control (<20 µm return to spot accuracy) and high-precision non-contact solenoid dispensing. The aspirate/dispense capabilities of the platform enable rigorous wash routines to be performed between samples.

The Nanodrop II is an ideal benchtop solution for use in spotting MALDI plates for protein characterization and quality control of synthetic oligos, as well as analysis of laser capture microdissection (LCM) cells. It includes two plate nests for source and MALDI plates. Single tip dispensing can be performed for rare compounds, and independent channel spotting enables spotting of unique plate maps.

In the application note "Improved Liquid Handling for MALDI Plate Spotting," developed in conjunction with Biosearch Technologies (Novato, CA), MALDI spotting performance for oligo QC was compared between a Nanodrop II and a BioMek FX from Beckman-Coulter under actual manufacturing use. It was determined that the Nanodrop generated higher quality spots (no missed or doughnut-shaped spots) and better spectra using 1/5 the volume of matrix and 1/10 the volume of oligo required by the Biomek. Laser desorption in five different positions was required for each Biomek spot, whereas one position was sufficient for a Nanodrop spot.

	Nanodrop	Biomek FX
Matrix spot volume	100 nL	500 nL
Oligo spot volume	50 nL	500 nL
Laser desorption shots per spot	1	5

	Biomek FX	Nanodrop	Platemaker(estimated)
Process time (minutes)	325	231	165

Features (all platforms)

Two plate nests for source plates and MALDI plates
Single tip access for rare compounds
Independent channel spotting enables spotting of unique plate maps
SBS plate adapters for MALDI plates
Easy to maintain and clean
Simple integration with plate handlers
Environmental control for proteins and oligonucleotides
Flexible aspirate and dispense settings
User defined syringe speeds and pressure set points
Ability to clean nozzles between runs
Low-dead volumes
Large dynamic volume range: 100 nL-40 uL
96, 384, 1536, 3456 plates (including low-profile and deep well)
User-friendly software
Simple to integrate with drivers available from most integrators

Platforms

Item	Description	Plate Positions	8-Tip Head	16-Tip Head	96-Tip Head	Syringe Channels	1,4, or 8-Tip Additions to all Wells
11638	Nanodrop II stage and fluidics	2	Yes	-	-	8	Yes
12056	Nanodrop Express stage/fluidics	1 or 2	-	Yes	-	16	Yes
11164	Screenmaker 96+8	5	Yes	-	Yes	16	Yes
12027	Platemaker HTS	5	Yes	-	Yes	104	Yes

Software

Item	Description
11727	Nanobuilder
10591	Nanodrop GUI (for Nanodrop only)

Accessories

Item	Description
11193	Reagent refill system (Nanodrop only)
	Wide-bore tip set (200 µm) (all platforms)

Specifications

Return-To-Spot Accuracy	0.1 mm
Aspiration Range, 8-Tip Head	0.1-500µL
Dispensing Range (8-Tip Non-Contact)	0.1-40µL
Dispensing Range (96-Tip)	Screenmaker: 0.1-125µL Platemaker: 0.1-80µL
Dispensing Precision, 8-Tip Head	CV<10% at 100nL, CV<7% at 200nL, CV<5% at 1µL
Dispensing Precision, 96-Tip Head	CV<15% at 100nL, CV<10% at 200nL, CV<5% at 1µL
Dispensing Accuracy, 8-Tip Head	±10% at 100nL, ±7% at 200nL, ±5% at >1 µL
Dispensing Accuracy, 96-Tip Head	Screenmaker: ±10% at 100-500nL, ±5% at >1 500nL Platemaker: ±10% at 100nL, ±7% at 200nL, ±5% at >1 µL
Dead Volume, 8-Tip head	1.5µL/channel at 1µL across 384-well plate
Dead Volume, 96-Tip head	<1µL/channel
Syringe Capacity	500, 1000µL