Energy Absorption & Capsids
The Bursting the Viral Capsid post was about increasing the viral capsid’s internal pressure, thereby bursting the capsid, and destroying the virus.
This post continues with the capsid-rupture theme, but considers a different technique, based on a molecular electromagnetic energy absorption, which, as we explain below, may be able to heat-rupture viruses in the body.
We start with some preamble: note that all molecules can absorb electromagnetic energy. The degree of energy absorption depends on the frequency of the electromagnetic radiation. For a given molecule, there will be a number of electromagnetic frequencies at which that molecule strongly absorbs energy from the incident radiation. The absorbed electromagnetic energy is converted to modes of vibration and rotation of the molecule, which serve to heat the molecule and its surroundings.
Energy absorption by rotational modes requires microwave frequencies. Energy absorption by vibrational modes requires infrared frequencies.
Note: microwave rotational absorption is only possible for dipolar molecules (for example water, ammonia and ethanol molecules).
The water molecule, for example, absorbs energy at both infrared and microwave frequencies. Microwave cooking ovens make use of this. These ovens generate microwave radiation at a frequency of 2.45 GHz, which gets absorbed by all the water molecules in the food, raising the temperature and heating the food. Interestingly, 2.45 GHz is a little lower than the frequency of maximum microwave energy absorption of the water molecule; this was purposely arranged, so as to ensure that the microwaves are not all absorbed by the first layer of water they encounter in the food, and can thus penetrate deeper. Note than the microwaves do not directly heat the other molecules present in the foodstuff; the microwave frequency is specifically tuned to get absorbed by the water molecules. Microwaves will, of course, heat any conducting material placed in the oven, but this is by a completely different mechanism, that of induced electrical current (the mechanism examined in the Bursting the Viral Capsid post).
For our purposes here, we want to heat-rupture a virus in vivo, via molecular energy absorption. So we need to find a target molecule within the capsid protein wall or capsid interior that we can heat up using electromagnetic radiation with a frequency that the molecule efficiently absorbs. We will probably have to use microwaves for this, only because these easily penetrate through the human body (by contrast, infrared penetrates only a few inches of body tissue at most, and so cannot reach and treat the body’s deep interior).
We must ensure two conditions:
(1) That our target molecules exist within the virion in high concentration, but not elsewhere in the body (or only in low concentration). We want to heat the virions, not the rest of the body.
(2) That the particular frequency of radiation used to heat the target molecule does not substantially heat the other molecules (eg, water) present in the body tissues. Otherwise the electromagnetic energy will be dissipated before it reaches the target molecules in the virions.
These two conditions can be handled empirically rather than theoretically. We can expose a culture of virions to each frequency (in turn) within the microwave spectrum, and for each frequency, measure the temperature rise in the culture. The temperature rise reflects the degree of energy transfer to (unknown) target molecules within the virion for that particular frequency. We will be on the lookout for frequencies that very efficiently transfer energy from our electromagnetic radiation to the virion. Then, out of the set of efficient transfer frequencies noted, we choose the frequency that is least absorbed by other body tissues. Thus we have frequency-tuned into selectively heating (and inactivating) the virions.
With this approach, and with sufficient microwave power levels, we may be able to deliver enough heat energy to the virions, so as to increase their internal temperature and pressure, and burst the capsid. Even if we cannot raise the temperature to capsid bursting point, the heat may be sufficient to destroy the viral DNA (or RNA), which equally serves to destroy the virion.
Safety for the patient is obviously of concern. It is important to use microwave frequencies that are not significantly absorbed anywhere else in the body, apart from in viral particles. We do not want to destroy healthy tissue.
Note: this microwave method assumes there are dipolar molecules within the virion, which, as explained, are the only class of molecules that will absorb microwave radiation.
Variations on the theme: if we cannot find a dipolar target molecule naturally present within the virion that we can heat up, then there may be a way to develop a drug-based dipolar target molecule which, when taken by a patient, incorporates itself with the viral DNA, or the capsid protein wall, or penetrates into the virion, so that the virion can then be heat-destroyed by microwaves.
Note: this method may equally be applied to destroying cancer cells, provided you find a suitable dipolar target molecule inside these cells, again, not present elsewhere in the body; or develop a drug which is selectively absorbed by cancer cells, and which can then serve as the target molecule for microwave heat-destruction of these cells.
Note that the virucidal methods here are equally valid (and in some ways better suited) for destroying viruses in blood transfusion products. Though blood used for transfusion is usually screened for such viruses as HIV, it nevertheless usually contains many other viruses, which can then infect the patient during transfusion and so possibly cause health problems in the long term. Furthermore, with blood products in vitro, infrared can be used as well as microwave, as obviously infrared’s inability to deeply penetrate tissue is not a concern in this case: the blood can be infrared-treated as it flows through a narrow tube. So we have a larger spectrum, in terms of finding suitable electromagnetic absorption frequencies to target molecules in virions.
Absorption versus frequency graphs for various common molecules can be found at this spectral database. Also useful: Molecular Absorption Spectra.
