Recent advances in platelet engineering for anti-cancer therapies

Platelets contribute a major role in hemostasis by clumping and coagulation at the site of blood vessel injuries. In light of recent findings of a close relationship between platelets and immunological response, as well as interactions between platelets and cancer cells, novel engineering strategies have emerged for the integration of platelets or platelet membrane (PM) with anti-cancer therapeutics. In this review, we discuss several recent innovations that use platelets or their membranes to circumvent host immune responses and target tumor cells with high specificity to deliver a range of pharmacological, photothermal, or immunologic agents for eradication of recalcitrant tumor cells. More specifically, we compare the relative advantages of using whole platelets versus single or hybrid PM to coat nanoparticle cargoes. These cargoes range from well-established anti-tumor apoptosis-inducing agents, to relatively new photothermal agents that can induce a feedback cascade in which they induce vascular damage to the tumor which recruits more platelet- or membrane-encapsulated agents to induce further damage. We also discuss the use of engineered platelets to produce programmed cell death-inducing platelet derived microparticles. This review provides an overview and future directions for this promising platelet-based biomimetic approach to anti-cancer therapy.