Author: Ozoihu Ephriam Maduabuchi
Department: Mechanical Engineering
Affiliation: Nnamdi Azikiwe University Awka

Measurement of contact angle and surface tension provides a better understanding of the interaction between the solids and liquids. Such interaction occurs between the HIV and T lymphocytes (CD4+) in liquid serum during infections. In order to study these interactions; the physiochemical properties such as the surface interfacial energies are explained using van der Waals concept of particle interactions as reported in Hamaker’s classical papers on separation of particles suspended in a liquid. The concepts of van der Waals forces are useful in predicting attraction or repulsion between the interacting particles (HIV and T lymphocyte). The surface free energies when determined from contact angle data are used to verify among other physiochemical properties, the negative Hamaker coefficient which confirms the possible repulsion between the virus and lymphocytes. The contact angles are measured on HIV infected bloods and uninfected bloods using the three probe liquids (water, glycerine and diiodomethane).The CD4+ cell counts were also measured using Partec flow Cytometry instrument. It was found that the contact angles measured on infected blood are generally higher than uninfected blood and tends to increase with decrease in CD4+ count for infected blood. From the contact angle data, the change in interfacial free energy of adhesion was found to be – 23.00 mJ/m2 indicating that van der force is attractive. This means that attraction occurs between HIV and lymphocyte during HIV infection. The absolute Hamaker coefficients for infected T4 cell A22,was found to be 0.227×10-16 mJ/m2 also indicating that attraction occurs between HIV and lymphocytes at a low surface energy of about 31.81mJ/m2 .The absolute Hamaker coefficient for uninfected T4 cell A11, were also obtained from the contact angle data and found to be 0.176×10-16 mJ/m2 .The positive value of Hamaker coefficient shows that attraction exist between HIV and T4 cells but lower value of A11 indicated less attraction for uninfected T4 cells and hence suggest a zero or negative concept that made repulsion to be attainable. However, the negative concept of combined Hamaker coefficient A132, was verified using the pair-wise summation of the geometric mean of the absolute Hamaker coefficients for lymphocytes A11, HIV A22 and Serum A33.The result (-0.6637X10-19mJ/m2) indicated that isolation of virus is attainable. In the resent work of Achebe, a negative value (-0.2809X10-25J) was obtained to support the claim that the van der Waal force is repulsive during particle separation. Therefore, finding an agent that will reduce the surface tension of serum (such that A11>A33>A22 or A11<A33<A22) to obtain a negative value of Hamaker coefficient will be the next step in formulating a drug to be recommended to the pharmaceutical industries for eradication of HIV infection and this calls for further research.

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