Recently the use of engineered viral scaffolds in biotechnology and medical applications has been increasing dramatically. T4 phage capsid derived nanoparticles (NPs) have potential advantages as sensors and in biotechnology. These applications require that the physical properties and cellular uptake of these NPs be understood. In this study we used a T4 deletion mutant to investigate the effects of removing both the Hoc and Soc proteins from the capsid surface on T4 tailless NPs. The surface charge, zeta potential, size, and cellular uptake efficiencies for both the T4 NP and T4 Delta Hoc Delta Soc NP mutant were measured and compared using dynamic light scattering and flow cytometry and significant differences were detected. Published by Elsevier Inc.