# Explorative Supercooling Technology for Prevention of Freeze Damages in Vaccines
###### Abstract
Upon freezing and thawing of a vaccine sample, the lattice structure composed of the vaccine's adsorbent (i.e., aluminum) and antigen breaks. The adsorbent, which becomes significantly heavier as its particulates separate, gradually settles at the bottom of the vaccine sample minutes after shaking the sample. Additional repetitions of freezing and thawing the vaccine sample are more likely to increase the sizes of adsorbent granules. These granules form a visibly clear supernatant while also forming white sedimentation at the bottom of the sample container [14]. In contrast, undamaged aluminum-adsorbed vaccines remain as white, homogeneous solutions even after shaking. [PERSON] et al. (2010) confirmed the value and validity of the shake test by proving freeze damage in aluminum-based vaccines. They designed a double-blind crossover model to compare the performance of the shake test conducted by trained workers with visual outcomes of phase-contrast microscopy. A total of 475 vials of eight different WHO prequalified freeze-sensitive vaccines from ten distinct manufacturers were used. Reporting 100% sensitivity, specificity, and positive predictive value in the shake test, the study provided confidence that the test could promote proper handling by vaccine dispensers [10]. Click or tap here to enter text. However, the test is not a preventive measure against vaccine temperature abuse; it may only detect previously frozen vaccines so that they are not administered to patients. Supercooling is a currently explored method whereby subzero storage of temperature-sensitive and water-based products--including vaccines--is possible without the temperature damage caused by freezing H\({}_{2}\)O. By definition, supercooling is a process of cooling biomaterials below their freezing points without ice crystal nucleation. Several innovative and practical approaches have been implemented to achieve stable and acceptable reproducibility of this supercooling phenomena in biological samples; such examples include surface sealing by oil and alcohol phases [15], high pressure [16; 17], ultrasound [18], and electrostatic fields [19]. However, these applications were limited to either fundamental exploration or food applications. Deep supercooling associated with biomedical applications studied by [PERSON] et al. [20] removed the storage medium-air interface using an immersible phase. The team sealed the surface of a small water sample (1 mL) with a hydrocarbon-based oil, (e.g., mineral oil, olive oil, and paraffin oil) that blocked ice formation at subzero temperatures for up to a week. By experimenting with more complex oils and with pure, simple hydrocarbons, such as alcohols and alkanes, they were able to keep a small volume of water and cell suspension (1 mL) supercooled at \(-20\)\({}^{\circ}\)C for 100 days and a larger volume (100 mL samples) for a week. A new supercooling technique for human organs was aimed to extend the period from the moment of extraction to 1.5 days rather than 5-10 h, providing a valuable window of time during which patients can obtain viable organs from donors. The invention perfused a liver with antifreeze chemicals to lower the freezing point below 0 \({}^{\circ}\)C and then accomplished uniform cooling throughout the organ, allowing the organ sample to hibernate or enter suspended dynamism [21]. However, the current state of their technologies has not matured enough to be widely adopted in commercial applications. The supercooling technology in this study utilizes a controlled, oscillating magnetic field to prevent freezing within biomaterials (Figure 1a). It is theorized that the magnetic field vibrates and disrupts the bonds between water molecules that form during ice crystal nucleation, thus preventing the nucleation of water. This electromagnetic technology--combined with pulsating electric fields--has already demonstrated its prevention of ice formation in meat and fruit products subject to subzero temperatures [22].