Exploration of Antigen Induced CaCO3 Nanoparticles for Therapeutic Vaccine.

Therapeutic vaccines possess particular advantages and show promising potential to combat burdening diseases, such as acquired immunodeficiency syndrome, hepatitis, and even cancers. An efficient therapeutic vaccine would strengthen the immune system and eventually eliminate target cells through cytotoxic T lymphocytes (CTLs). Unfortunately, insufficient efficacy in triggering such an adaptive immune response is a problem that remains unsolved. To achieve efficient cellular immunity, antigen-presenting cells must capture and further cross-present disease-associated antigens to CD8 T cells via major histocompatibility complex I molecules. Here, a biomimetic strategy is developed to fabricate hierarchical ovalbumin@CaCO3 nanoparticles (OVA@NP, ≈500 nm) under the templating effect of antigen OVA. Taking advantage of the unique physicochemical properties of crystalline vaterite, cluster structure, and high loading, OVA@NP can efficiently ferry cargo antigen to dendritic cells and blast lysosomes for antigen escape to the cytoplasm. In addition, the first evidence that the physical stress from generated CO2 induces autophagy through the LC3/Beclin 1 pathways is presented. These outcomes cooperatively promote antigen cross-presentation, elicit CD8 T cell proliferation, ignite a potent and specific CTL response, and finally achieve prominent tumor therapy effects.

Biomimetically Engineered Demi-Bacteria Potentiate Vaccination against Cancer.

Failure in enhancing antigen immunogenicity has limited the development of cancer vaccine. Inspired by effective immune responses toward microorganisms, demi-bacteria (DB) from Bacillus are engineered as carriers for cancer vaccines. The explored hydrothermal treatment enables the Bacillus to preserve optimal pathogen morphology with intrinsic mannose receptor agonist. Meanwhile, the treated Bacillus can be further endowed with ideal hollow/porous structure for efficient accommodation of antigen and adjuvant, such as CpG. Therefore, this optimal engineered nanoarchitecture allows multiple immunostimulatory elements integrate in a pattern closely resembling that of bacterial pathogens. Such pathogen mimicry greatly enhances antigen uptake and cross-presentation, resulting in stronger immune activation suitable for cancer vaccines. Indeed, DB-based biomimetic vaccination in mice induces synergistic cellular and humoral immune responses, achieving potent therapeutic and preventive effects against cancer. Application of microorganism-sourced materials thus presents new opportunities for potent cancer therapy.

Breaching the Hyaluronan Barrier with PH20-Fc Facilitates Intratumoral Permeation and Enhances Antitumor Efficiency: A Comparative Investigation of Typical Therapeutic Agents in Different Nanoscales.

In contrast to traditional strategies based on external driving forces, an internal path for intratumoral delivery is explored by degrading the tumor microenvironment component hyaluronan. Natural hyaluronidase PH20 and constructed long-acting PH20-Fc have been used to achieve this objective. It has been then evaluated how these agents facilitate the diffusion of the following typical therapeutic agents varying in nanoscales: doxorubicin (≈1.5 × 1.0 × 0.7 nm) chemotherapy, trastuzumab (10-15 nm) biotherapy, and gold nanorod (≈100 × 35 nm) thermotherapy. In traditional 2D cultures, PH20 and PH20-Fc have little influence on cytotoxicity due to lack of a tumor microenvironment. However, the cytotoxicities of the three therapeutic agents in 3D tumor spheroids are all enhanced by PH20 or PH20-Fc because hyaluronan degradation facilitates therapeutic penetration and accumulation. Furthermore, in vivo evaluations reveal that the significantly prolonged circulation time of PH20-Fc leads to accumulation in the tumor and subsequent hyaluronan degradation. Consequently, PH20-Fc coadministration further inhibits tumor growth. The performance of PH20-Fc varies for the three therapeutic agents due to their different nanoscales. Trastuzumab benefits most from combination with PH20-Fc. The results provide here novel insights that can aid in the development of more effective hyaluronidase-based therapeutic systems.

Positively charged armed nanoparticles demonstrate their precise delivery performance for effective treatment of chorioretinal diseases.

Recruiting positively charged armed nanoparticles into the ocular fundus was achieved by utilizing the natural intraocular electrical field. Their subsequent penetration into the fundus sub-layers was also tuned by optimizing the surface charge density. In addition to the sustained release behavior, such a precise delivery fulfilled various intraocular delivery requirements for different chorioretinal diseases.

Exploration of graphene oxide as an intelligent platform for cancer vaccines.

We explored an intelligent vaccine system via facile approaches using both experimental and theoretical techniques based on the two-dimensional graphene oxide (GO). Without extra addition of bio/chemical stimulators, the microsized GO imparted various immune activation tactics to improve the antigen immunogenicity. A high antigen adsorption was acquired, and the mechanism was revealed to be a combination of electrostatic, hydrophobic, and π-π stacking interactions. The "folding GO" acted as a cytokine self-producer and antigen reservoir and showed a particular autophagy, which efficiently promoted the activation of antigen presenting cells (APCs) and subsequent antigen cross-presentation. Such a "One but All" modality thus induced a high level of anti-tumor responses in a programmable way and resulted in efficient tumor regression in vivo. This work may shed light on the potential use of a new dimensional nano-platform in the development of high-performance cancer vaccines.

Erythrocyte membrane-coated NIR-triggered biomimetic nanovectors with programmed delivery for photodynamic therapy of cancer.

A new type of photodynamic therapy (PDT) agents using upconversion nanoparticles (UCNPs) with incorporated photosensitizers as the inner core and an erythrocyte membrane (RM) decorated with dual targeting moieties as the cloak is developed. Owing to the endogenous nature of RM, the RM-coating endows the PDT agents with perfect biocompatibility and stealth ability to escape from the entrapment by the reticulo-endothelial system (RES). More importantly, owing to the unique nature of erythrocyte as an oxygen carrier in the blood, the RM outer layer of the agents unequivocally facilitates the permeation of ground-state molecular oxygen ((3)O2) and the singlet oxygen ((1)O2) as compared to the previously developed PDT agents with other types of coating. Another salient feature of the as-prepared PDT platform is the decoration of RM with dual targeting moieties for selective recognition of cancer cells and mitochondrial targeting, respectively. The synergistic effect of RM coating and dual-targeting of such feature-packed agents are investigated in tumor-bearing mice and the improved PDT therapeutic efficacy is confirmed, which is the first paradigm where RM-coated NIR-triggered nanovectors with programmed delivery ability is applied in PDT of tumor in vivo.

Surface-engineered graphene navigate divergent biological outcomes toward macrophages.

The "nano-bio" interface profoundly shapes the interaction between cells and nanomaterials and can even decide a cell's fate. As a nascent two-dimensional material, graphene has many unique attributes and is proposed to be a promising candidate for biomedical applications. Thus, for graphene-based applications, it is necessary to clarify how the graphene surface navigates biological outcomes when encountering "janitorial" cells (macrophages). For this purpose, we synthesized nanographene oxide (nGO) and engineered the surface with polyethylene glycol (PEG), bovine serum albumin (BSA), and poly(ether imide) (PEI). In contrast to pristine nGO, decoration with PEG and BSA hindered endocytosis and improved their benignancy toward macrophages. Contrarily, nGO-PEI commenced with favorable endocytosis but then suffered stagnation due to compromised macrophage viability. To unravel the underlying mechanisms regulating these diverse macrophage fates, we built a stepwise analysis. Compared to the others, nGO-PEI tended to interact electrostatically with mitochondria after their cellular internalization. Such an unexpected encounter disrupted the normal potential and integrity of mitochondria and then elicited an alteration in reactive oxygen species and cytochrome c. These responses further initiated the activation of the caspase family and ultimately dictated cells to undergo apoptosis. The advances described above will complement our knowledge of graphene functionality and serve to guide its application in biotechnological applications.

Programmed co-delivery of paclitaxel and doxorubicin boosted by camouflaging with erythrocyte membrane.

Combination chemotherapy has been proven promising for cancer treatment, but unsatisfactory therapeutic data and increased side effects slow down the development in the clinic. In this study, we develop an effective approach to co-encapsulate a hydrophilic-hydrophobic chemotherapeutic drug pair (paclitaxel and doxorubicin) into magnetic O-carboxymethyl-chitosan nanoparticles. To endow them with the ability of programmed delivery, these carriers are further camouflaged with an Arg-Gly-Asp anchored erythrocyte membrane. Compared with the traditional polyethylene glycol coating method, this biomimetic decoration strategy is demonstrated to be superior in prolonging circulation time, improving tumor accumulation, facilitating tumor uptake, and tuning intracellular fate. These outstanding properties enable the as-designed nanodevice to exhibit greater tumor growth inhibition ability and much lower side effects than the combined use of commercial formulations.

Superior intratumoral penetration of paclitaxel nanodots strengthens tumor restriction and metastasis prevention.

Recently discovered intratumoral diffusion resistance, together with poor solubility and nontargeted distribution of chemotherapeutic drugs, has significantly impaired the performance of cancer treatments. By developing a well-designed droplet-confined/cryodesiccation-driven crystallization approach, we herein report the successful preparation of nanocrystallites of insoluble chemotherapeutic drug paclitaxel (PTX) in forms of nanodots (NDs, ≈10 nm) and nanoparticles (NPs, ≈70 nm) with considerably high drug loading capacity. Superficially coated Pluronic F127 is demonstrated to endow the both PTX nanocrystallites with excellent water solubility and prevent undesired phagocyte uptake. Further decoration with tumor-penetrating peptide iRGD, as expected, indiscriminatively facilitates tumor cell uptake in traditional monolayer cell culture model. On the contrary, distinctly enhanced performances in inward penetration and ensuing elimination of 3D multicellular tumor spheroids are achieved by iRGD-NDs rather than iRGD-NPs, revealing the significant influence of particle size variation in nanoscale. In vivo experiments verify that, although efficient tumor enrichment is achieved by all nanocrystallites, only the iRGD-grafted nanocrystallites of ultranano size realize thorough intratumoral delivery and reach cancer stem cells, which are concealed inside the tumor core. Consequently, much strengthened restriction on progress and metastasis of orthotopic 4T1 mammary adenocarcinoma is achieved in murine model, in sharp contrast to commercial PTX formulation Taxol.

Nanoparticles-based multi-adjuvant whole cell tumor vaccine for cancer immunotherapy.

Whole cell tumor vaccine (WCTV), as a potential treatment modality, elicits limited immune responses because of the poor immunogenicity. To address this issue, researchers have attempted to transduce a cytokine adjuvant into tumor cells, but these single-adjuvant WCTVs curtail the high expectations. In present study, we constructed a multi-adjuvant WCTV based on the nanoparticles modified with cell penetrating peptide, which could facilitate the transportation of granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin 2 (IL-2) into tumor cells. After inactivation, as-designed multi-adjuvant WCTV exhibited programmed promotions on DC recruitment, antigen presentation, and T-cell activation. In vivo evaluations demonstrated the satisfactory effects on tumor growth suppression, metastasis inhibition, and recurrence prevention. Therefore, the nanoparticles-based multi-adjuvant WCTV may serve as a high-performance treatment for anti-tumor immunotherapy.

Molecular structure matters: PEG-b-PLA nanoparticles with hydrophilicity and deformability demonstrate their advantages for high-performance delivery of anti-cancer drugs.

Various carriers are being advanced for anti-cancer therapy, which can protect drugs and ferry them to the target site. However, little understanding exists regarding the effect of molecular structure on anti-cancer drug delivery efficiency. To fill this knowledge gap, we take poly(lactic acid) (PLA), poly(lactide-co-glycolide) (PLGA), and poly-ethylene glycol-co-poly-lactide (PEG-b-PLA) polymers as prototype materials and comparatively explore the inherent relationship between the molecular structure and the delivery ability. Compared with PLA and PLGA NPs, PEG-b-PLA ones possess the advantages of longer blood circulation time, more tumor accumulation, and better intratumoral delivery ability. Subsequent mechanism investigations reveal that the molecular structure will regulate the polymer arrangement and render NPs different hydrophilicity/deformability, which dictate the distinct delivery performances. Finally, the superior PEG-b-PLA NPs are further loaded with the anti-cancer drug paclitaxel (PTX) and functionalized with magnetic (M) Fe3O4 nanocrystals. As-designed PTX/M PEG-b-PLA NPs show much better tumor inhibition efficacy and fewer side effects than the commercialized Taxol® formulation, strongly supporting their use as high-performance carriers for anti-cancer therapy.

Targeted delivery of insoluble cargo (paclitaxel) by PEGylated chitosan nanoparticles grafted with Arg-Gly-Asp (RGD).

Poor delivery of insoluble anticancer drugs has so far precluded their clinical application. In this study, we developed a tumor-targeting delivery system for insoluble drug (paclitaxel, PTX) by PEGylated O-carboxymethyl-chitosan (CMC) nanoparticles grafted with cyclic Arg-Gly-Asp (RGD) peptide. To improve the loading efficiency (LE), we combined O/W/O double emulsion method with temperature-programmed solidification technique and controlled PTX within the matrix network as in situ nanocrystallite form. Furthermore, these CMC nanoparticles were PEGylated, which could reduce recognition by the reticuloendothelial system (RES) and prolong the circulation time in blood. In addition, further graft of cyclic RGD peptide at the terminal of PEG chain endowed these nanoparticles with higher affinity to in vitro Lewis lung carcinoma (LLC) cells and in vivo tumor tissue. These outstanding properties enabled as-designed nanodevice to exhibit a greater tumor growth inhibition effect and much lower side effects over the commercial formulation Taxol.