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Despite the promising efficacy of immunoregulation in cancer therapy, the clinical benefit has been restricted by inefficient infiltration of lymphocytes in the evolution of immune evasion. Also, immune-related adverse events have often occurred due to the off-target binding of therapeutics to normal tissues after systematic treatment. In light of this, we have developed a synergistic immunotherapy strategy that locally targets the immunoinhibitory receptor programmed cell death protein 1 (PD1) and immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO) for the treatment of melanoma through a microneedle-based transcutaneous delivery approach. The embedded immunotherapeutic nanocapsule loaded with anti-PD1 antibody (aPD1) is assembled from hyaluronic acid modified with 1-methyl-dl-tryptophan (1-MT), an inhibitor of IDO. This formulation method based on the combination strategy of "drug A in carriers formed by incorporation of drug B" facilitates the loading capacity of therapeutics. Moreover, the resulting delivery device elicits the sustained release and enhances retention of checkpoint inhibitors in the tumor microenvironment. Using a B16F10 mouse melanoma model, we demonstrate that this synergistic treatment has achieved potent antitumor efficacy, which is accompanied by enhanced effective T cell immunity as well as reduced immunosuppression in the local site.

Ischemic stroke is a leading cause of long-term disability and death worldwide. Current drug delivery vehicles for the treatment of ischemic stroke are less than satisfactory, in large part due to their short circulation lives, lack of specific targeting to the ischemic site, and poor controllability of drug release. In light of the upregulation of reactive oxygen species (ROS) in the ischemic neuron, we herein developed a bioengineered ROS-responsive nanocarrier for stroke-specific delivery of a neuroprotective agent, NR2B9C, against ischemic brain damage. The nanocarrier is composed of a dextran polymer core modified with ROS-responsive boronic ester and a red blood cell (RBC) membrane shell with stroke homing peptide (SHp) inserted. These targeted "core-shell" nanoparticles (designated as SHp-RBC-NP) could thus have controlled release of NR2B9C triggered by high intracellular ROS in ischemic neurons after homing to ischemic brain tissues. The potential of the SHp-RBC-NP for ischemic stroke therapy was systematically evaluated in vitro and in rat models of middle cerebral artery occlusion (MCAO). In vitro results showed that the SHp-RBC-NP had great protective effects on glutamate-induced cytotoxicity in PC-12 cells. In vivo pharmacokinetic (PK) and pharmacodynamic (PD) testing further demonstrated that the bioengineered nanoparticles can drastically prolong the systemic circulation of NR2B9C, enhance the active targeting of the ischemic area in the MCAO rats, and reduce ischemic brain damage.

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