Recent advances in natural polymer-based drug delivery systems

Natural polymers have been extensively explored as the vehicles for encapsulation and delivery of drugs and other bioactive molecules, which have attracted tremendous attention. Their inherent advantages in marvelous biocompatibility, controlled enzyme degradation, specific interactions with some biomolecules, and easy modification endow them with versatility in drug delivery. In this perspective, the drug delivery systems (DDS) constructed by representative natural polymers, polysaccharides (chitosan and hyaluronic acid) and proteins (silk fibroin and collagen), are generally summarized. Payloads mainly involve small molecular weight drug, proteins, and DNA for the applications of tissue engineering, wound healing or anticancer therapy. Moreover, the DDS constructed by their derivatives and with other materials also have been presented focusing on the chemical and morphological modifications, the addtions of smart stimuli-triggered or targeted motifs and so on, which evidently promoted the delivery and therapy efficiency. Obviously, more intelligent and specific delivery strategies will be developed and more multifunctional natural polymers based carriers will be expended in the future. We try to seek more insights into the evolution of delivery system so as to figure out what we will truly gain in the next few decades to come.