Sariputra, all dharmas are marked with emptiness.
Dharma is a comprehensive term with a variety of meanings and applications at multiple levels for both Hindus and Buddhists. In the sutra here, the term is used in the sense of a fundamental unit of existence, the building blocks of the empirical personality and its world. In this sense, the dharmas are something like the atoms of Democritus or the monads of Leibniz. The term "point-instant" comes closest perhaps to capturing the insight behind the term dharma within the context of the Heart Sutra. These "point-instants" have miniscule extension in space and have practically no endurance. Again, the analogy of wave-particle unpredictability best captures the drama of "point-instants."
It is out of these dharmas, the fundamental units, that the skandhas are made. Since all existence is manifested through one or another of the skandhas, it seems inevitable that all existence is a conglomeration of dharmas. But the dharmas themselves are not any solid objects positioned in time and space, just as the waves and particles of quantum physics are not. The dharmas make a momentary appearance and then flicker out. They appear as a result of the interplay of underlying sunyata, the core energy; hence they are inherently empty. There is absolutely nothing one can hold on to.