An effective mask-free method for fabricating high-aspect-ratio pillarlike nanostructures over a large area of a quartz surface via a simple O-2 and CF4 two-step reactive ion etching (RIE) procedure is developed. The nanostructured quartz surfaces are successfully combined with the engineered viral particles derived from hepatitis B virus capsid, yielding a novel 3D assay system with attomolar sensitivity, which has great potential for use in sensitive and early detection of various disease