Frequently Asked Questions

Magnetic field

Are DM100 Applicators multifrequency devices?
Yes. All Applicators can work in more than one frequency

Can the frequency of the magnetic field be selected continuously or the device works at discrete frequencies?
The devices work with highly optimized resonant LC tanks, so the frequencies are discrete. DM1 and DM3 can be tuned for up to 8 frequencies (each frequency is called a “mode”), and DM2 for up to 4.

What are the maximum applied fields at the different frequencies?
Typically, we supply 300Gauss for every mode and DM1 and DM3, and 200Gauss for DM2. This difference is due to the fact that DM2 has a much wider coil than the other two. Anyway, if you prefer a small DM2 coil for bigger fields, we can do that. Custom designs can achieve up to 500G or more in some models.
All the operation is done by the software, you never touch the coils or any internal components. This is the only way to achieve stability and reliability on the field generation process.
One important detail: these field intensities are measured, stabilized and calibrated for each coil individually. They are not estimated by general formulas.

What is the volume of field homogeneity for the different applicators?
It depends on the model and the customization options. In DM1, field homogeneity is better than ±5% across a 1ml sample. You can ask for custom homogeneity values. You always get a field map of your coil with the calibration documentation, so you are aware of the field distribution in every experiments.

DM1 – Calorimetry

What is the coil diameter in DM1?
Depends on custom options. It is optimized for each applicator. Anyway, DM1 is not about coil diameter, it is about vial volume: the standard model is for 2ml vial. Field homogeinity for a 2ml sample is better than ±8%. Custom designs can achive up to 2% homogeinity

Does the insulation of the sample from the coil rely only on a vacuum shield, or there is also other means of cooling the coils? Does the heating of the coils interfere with the sample heating?
In DM1 (and in DM2 with the dewar option, the CAL) the sample vial is inserted into a dewar with a vacuum chamber. This dewar is an open one, so you have to connect a vacuum pump to achieve good isolation (not included). This vacuum isolation is only for calorimetry purposes.
The cooling of the coil is done for security, stability and reliability purposes, and it is achieved with an external water chiller (not included).
DM1 and DM2 (with CAL) are fine calorimetry systems for SAR determination. Typically, when you apply maximum field, maximum frequency in a pure water sample for about one hour, the temperature variation of the water will be of about 1Kº or 2Kº, depending on the quality of the water chiller, and of course, how carefully the experiment was made regarding previous thermalization and preparation. For a typical SAR experiment (some 10 or 15 minutes) this is a negligible variation.

What is the minimum and maximum volume of the sample holder? Can a different sample holder be used if smaller volumes are desirable, say 0.5 mL or less?
Sample holders in standard DM1 is designed for better precision when filled with 1ml-1,5ml. The minimun recommended is 0,5ml. The smaller the sample, the weaker the signal, so you could, in fact, put less that 0,5ml into the sample vial, but the thermalization between the sample and the vial can be an important source of error for the standard DM1 vial. If the customer is interested in smaller volumes, we could design a sample column for 1ml vials, or less. But again: the smaller the sample, the weaker the signal. It’s not a good idea to work with, for example, 200ul.

DM2 – Multiple uses

Apart from the software, power and size, DM2 looks like a device that only provides a normal coil. Why should I consider it better than normal induction devices?
DM2 is the most flexible and developed device of the series. With the addition of current and future accessories it can do IR imaging, calorimetry (like DM1), animal experimentation (like DM3), cell culture experiments, controlled atmosphere and temperature procedures, combined tests, etc.
nB can also design the accessories you imagine for it. Drug release, tissue engineering, material science and many other areas can find in DM2 the best tool for new applications.

DM3 – In vivo experimentation

Why DM3 is better for invivo experiments that any induction coil, like, for example DM2?
DM3 is a controlled environment for in vivo InH (Induction nanoHeating) experiments. Not only it warrantees reliable and repeatable magnetic field parameter, but when combined with some of the available accessories, it allows you to run fully integrated measurements like heart rate, blood pressure, IR thermal imaging, multiple local thermometric probing.
DM2 can be used for animal tests, but it is not the optimal setup for that. These devices, of course, cannot be tilted, so DM2 coil is always vertical. Most researches prefer to do in vivo test in a horizontal position.
If you want to run occasional invivo tests, DM2 can do the job. But if you want to develop a strong research line on clinical hyperthermia or magnetically controlled drug delivery therapies, DM3 is the right tool.

The notes/video indicated some kind of holder for the mouse/model. Which other options for DM3 do you offer?
DM3 sample chamber can be customized in many ways. The one in the video is an animal bed, open air, with a pancake coil located at the left side of the mouse, where the red disk is shown. In this model, the experiment is at room temperature.

What are the size limitations on the sample holder for DM3? The section where mouse is held seems a bit small.
DM3 can be customized for many kind of (small) animals. There is not severe limitation for that, and that can be done without special fees.

What is the uniformity of field for DM3?
The DM3 you see in the video is not designed for high uniformity but the opposite: strong field over the skin and rapidly fading as measured deeper inside the mouse, since it’s meant for treating surface tumors. But we can build a DM3 according to a customer’s uniformity preferences. Some researchers prefer the same intensity all over the animal, some prefer the field not uniform.

Cooling and vacuum

Do I need a water chiller?
Yes, all DM100 applicators need a controlled supply of cooling water

Do you sell water chillers?
No, we do not manufacture or sell water chillers. Nevertheless, we can help you find the best solution for you from a third party supplier.

What kind of water chiller do you recommend?
Closed water circuit. Typical pressure: 2,9 bar. Flow: 7litres/m.

Can I use tap water for cooling the coils?
We do not recommend tap water because water temperature and pressure affects the quality of the measurement and the stability of the system. DM100 is a system designed for maximum control of the thermal variables during the experiment. The temperature of the coil is measured in real time, and reported by the software to the user, for security and for fine tuning of the calorimetry calculations.

Do I need a vacuum pump?
Only for DM1 and for DM2 working with CAL accessory. Vacuum pump is used in DM100 series to guarantee the best isolation between the sample and the environment for calorimetry purposes, so it is only needed when your applicator has a dewar installed on it, which is the case of standard DM1 and of any DM2 when the CAL accessory is installed.

Do you sell vacuum pumps?
No, we do not manufacture or sell vacuum pumps. Nevertheless, we can help you find the best solution for you from a third party supplier.

What kind of vacuum pump do you recommend?
Typical vacuum systems for DM100 series consist in a rotary-turbo pump set. Typical pressure in the inside of the vaccum chamber is around 10^-6 Pa.

Sensors

Could it be possible to add further thermometers to have different temperature points, and integrate their measurements in Maniac?
Yes. DM2 and DM3 offer 3 optical thermometer ports. These are state of the art high accuracy probes.

Can I do logging and direct measurements with the IR1 infrared camera option?
Yes. You can also graphically select the point you want to set as control point and use it as a sensor even on the temperature control loop. This is very powerful tool for hyperthermia therapy research.

Can I do infrared measurements of internal organs of a mouse with IR1 infrared camera option?
No. Infrared imaging shows the temperature distribution on the surface of the specimen.

Can I add more sensors to the system?
MANIAC is designed to accept future devices, and with a wide horizon of expandability. The nB team can work with you to adapt the sensing technology of your interest.

Samples and experiments

What is the optimum concentration of nanoparticles for a successful test?
There’s no general answer to that question. Most cases, the higher the concentration, the better the signal. But more concentrated colloids tend to be more unstable, so it depends on the colloid itself. That’s usually a question that you should expect from someone not really familiar with colloids or at least with SAR measurement.
Regarding clinical trials it’s even more difficult, since each application is different.

How much time is a single experiment usually?
Again, there is not a standard answer. A really rough idea would be to consider 15-45 min.

How much space do I need in my lab  to mount a experimental workstation using the DM100 Series devices?
In the picture below attached you can see the dimensions of a system consisting of a controller (DMC1) and an applicator (DM1, DM2 or DM3). You can also see some significant distances, such as the separation between the two devices (50 cm) or the recommended distance between the controller and the wall (approximately 30 cm).

Dimensiones del conjunto aplicador - controlador
Dimensiones del conjunto aplicador – controlador