Highly Prolonged Release of the Cancer Vaccine and Immunomodulator via a Two-Layer Biodegradable Microneedle for Prophylactic Treatment of Metastatic Cancer

Simultaneous sustained release of cancer vaccines and immunomodulators may effectively trigger durable immune responses and avoid multiple administrations. Here, we established a biodegradable microneedle (bMN) based on a biodegradable copolymer matrix made of polyethylene glycol (PEG) and poly(sulfamethazine ester urethane) (PSMEU). This bMN was applied to the skin and slowly degraded in the epidermis/dermis layers. Then, the complexes composed of a positively charged polymer (DA3), cancer DNA vaccine (pOVA), and toll-like receptor 3 agonist poly(I/C) were synchronously released from the matrix in a pain-free manner. The whole microneedle patch was fabricated with two layers. The basal layer was formed using polyvinyl pyrrolidone/polyvinyl alcohol that could be rapidly dissolved upon applying the microneedle patch to the skin, whereas the microneedle layer was formed by complexes encapsulating biodegradable PEG-PSMEU, which was stuck at the injection site for sustained release of therapeutic agents. According to the results, 10 days is the time for the complexes to be completely released and express specific antigens in antigen-presenting cells in vitro and in vivo. It is noteworthy that this system could successfully elicit cancer-specific humoral immune responses and inhibit metastatic tumors in the lungs after a single shot of immunization.

Self-Assembled Amphiphilic Starch Based Drug Delivery Platform: Synthesis, Preparation, and Interactions with Biological Barriers

Core-shell structured nanoparticles (NPs) render the simultaneous coloading capacity of both hydrophobic and hydrophilic drugs and may eventually enhance therapeutic efficacy. In this study, we employed a facile squalenoylation technology to synthesize a new amphiphilic starch derivative from partially oxidized starch, which self-assembled into core-shell starch NPs (StNPs) only at a squalenyl degree of substitution (DoS) of ∼1%. The StNPs characteristics could be tuned as the functions of the polymer molecular weight, DoS, and NPs concentration. The biopharmaceutical features of the StNPs, including colloidal stability, carrier properties, and biocompatibility, were carefully investigated. The interaction study between StNPs and mucin glycoproteins, the main organic component of mucus, revealed a moderate mucin interacting profile. Furthermore, the StNPs also showed good penetration through Pseudomonas aeruginosa biofilms. These results nominate StNPs as a versatile drug delivery platform with potential applications for mucosal drug delivery and the treatment of persistent infections.

Highly potent intradermal vaccination by an array of dissolving microneedle polypeptide cocktails for cancer immunotherapy

Despite recent advances in cancer therapy using vaccines, the efficacy of vaccine regimens remains to be improved. Cutaneous transportation of biomolecules, particularly DNA vaccines, has potentially improved the therapeutic efficacy and has been found to be an appealing approach in cancer immunotherapy. Nevertheless, the effectiveness of transdermal vaccination is limited by the lack of efficacious immune stimulation. Here, to elicit strong immunogenicity in target cells, we propose an array of dissolving microneedle cocktails for pain-free implantation and triggered release of vaccines and adjuvants at cutaneous tissues. The microneedle cocktails comprising a bioresorbable polypeptide matrix with a nanopolyplex, which include cationic amphiphilic conjugates with ovalbumin-expressing plasmid OVA (pOVA) and immunostimulant-polyinosinic:polycytidylic acid (poly(I:C)), were prepared using a one-pot synthesis. The cationic nanopolyplex effectively transported pOVA and poly(I:C) into the intracellular compartments of dendritic cells and macrophages. Cutaneous implantation of microneedle cocktails on mice elicits a stronger antigen-specific antibody response than subcutaneous administration of the microneedle-free nanopolyplex. Compared with traditional vaccination, the dissolving microneedle cocktails enhanced the antibody recall memory after challenge; remarkably, the cocktail-based therapeutic vaccination also resulted in enhanced lung clearance of cancer cells. The dissolving microneedle cocktail therapy based on the triggered release of immunomodulators and adjuvants synergistically augmented the therapeutic effect in B16/OVA melanoma tumors.

Smart pH-Responsive Nanocube-Controlled Delivery of DNA Vaccine and Chemotherapeutic Drugs for Chemoimmunotherapy

The combination of chemotherapeutic agents with immune stimulating agents for treating degenerative diseases, called chemoimmunotherapy, has emerged as a promising cancer treatment modality. Despite the tremendous potential, chemoimmunotherapy by the combination of drugs and immune stimulators often suffers because of the lack of controlled delivery nanostructures in the microenvironment. To this end, we show that by using pH-responsive smart nanocubes (NCs), cancer cells and tumor-associated immune cells can be precisely targeted with a chemotherapeutic agent (doxorubicin, DOX) and immune stimulating agent (plasmid ovalbumin, pOVA) for enhanced chemoimmunotherapy. The pH-responsive smart NCs protect payloads from nuclease degradation and avoid renal clearance and undergo supersensitive structural change at the extracellular tumor regions that mediate efficient release. Concurrent release of pOVA vaccines encoding tumor-specific antigen laden with polyplexes were loaded on tumor-associated immune cells and produce antigen-specific humoral immune response, whereas DOX enables effective infiltration into the cancer cells and is involved in the eradication of tumor tissues. The amount of anti-OVA IgG1 antibody produced by the intravenous administration of NC formulation was similar to that of free OVA formulation. Importantly, the combined delivery of pDNA and DOX using NCs showed significantly enhanced antitumor efficacy in B16/OVA melanoma tumor xenografts, which remarkably outperforms the monotherapy counterparts. These results suggest that pH-responsive smart NCs laden with pDNA and DOX provide a promising nanostructure for chemoimmunotherapy that simultaneously involves cancer cell killing and stimulates antigen-specific immune response to prevent cancer recurrence.

Modularly engineered injectable hybrid hydrogels based on protein-polymer network as potent immunologic adjuvant in vivo

Lymphoid organs, which are populated by dendritic cells (DCs), are highly specialized tissues and provide an ideal microenvironment for T-cell priming. However, intramuscular or subcutaneous delivery of vaccine to DCs, a subset of antigen-presenting cells, has failed to stimulate optimal immune response for effective vaccination and need for adjuvants to induce immune response. To address this issue, we developed an in situ-forming injectable hybrid hydrogel that spontaneously assemble into microporous network upon subcutaneous administration, which provide a cellular niche to host immune cells, including DCs. In situ-forming injectable hybrid hydrogelators, composed of protein-polymer conjugates, formed a hydrogel depot at the close proximity to the dermis, resulting in a rapid migration of immune cells to the hydrogel boundary and infiltration to the microporous network. The biocompatibility of the watery microporous network allows recruitment of DCs without a DC enhancement factor, which was significantly higher than that of traditional hydrogel releasing chemoattractants, granulocyte-macrophage colony-stimulating factor. Owing to the sustained degradation of microporous hydrogel network, DNA vaccine release can be sustained, and the recruitment of DCs and their homing to lymph node can be modulated. Furthermore, immunization of a vaccine encoding amyloid-β fusion proteinbearing microporous network induced a robust antigen-specific immune response in vivo and strong recall immune response was exhibited due to immunogenic memory. These hybrid hydrogels can be administered in a minimally invasive manner using hypodermic needle, bypassing the need for cytokine or DC enhancement factor and provide niche to host immune cells. These findings highlight the potential of hybrid hydrogels that may serve as a simple, yet multifunctional, platform for DNA vaccine delivery to modulate immune response.

Smart injectable biogels based on hyaluronic acid bioconjugates finely substituted with poly(β-amino ester urethane) for cancer therapy

In situ-forming injectable biogels (IBGs) have been developed for the programmed delivery of potent chemotherapeutic drugs.

Physically crosslinked injectable hydrogels for long-term delivery of oncolytic adenoviruses for cancer treatment

A dual pH- and temperature-responsive physically crosslinked and injectable hydrogel system was developed for efficient and long-term delivery of oncolytic adenoviruses (Ads).

Enhanced Cancer Vaccination by In Situ Nanomicelle-Generating Dissolving Microneedles

Efficient delivery of tumor antigens and immunostimulatory adjuvants into lymph nodes is crucial for the maturation and activation of antigen-presenting cells (APCs), which subsequently induce adaptive antitumor immunity. A dissolving microneedle (MN) has been considered as an attractive method for transcutaneous immunization due to its superior ability to deliver vaccines through the stratum corneum in a minimally invasive manner. However, because dissolving MNs are mostly prepared using water-soluble sugars or polymers for their rapid dissolution in intradermal fluid after administration, they are often difficult to formulate with poorly water-soluble vaccine components. Here, we develop amphiphilic triblock copolymer-based dissolving MNs in situ that generate nanomicelles (NMCs) upon their dissolution after cutaneous application, which facilitate the efficient encapsulation of poorly water-soluble Toll-like receptor 7/8 agonist (R848) and the delivery of hydrophilic antigens. The sizes of NMCs range from 30 to 40 nm, which is suitable for the efficient delivery of R848 and antigens to lymph nodes and promotion of cellular uptake by APCs, minimizing systemic exposure of the R848. Application of MNs containing tumor model antigen (OVA) and R848 to the skin of EG7-OVA tumor-bearing mice induced a significant level of antigen-specific humoral and cellular immunity, resulting in significant antitumor activity.

Smart vaccine delivery based on microneedle arrays decorated with ultra-pH-responsive copolymers for cancer immunotherapy

Despite the tremendous potential of DNA-based cancer vaccines, their efficacious delivery to antigen presenting cells to stimulate both humoral and cellular response remains a major challenge. Although electroporation-based transfection has improved performance, an optimal strategy for safe and pain-free vaccination technique remains elusive. Herein, we report a smart DNA vaccine delivery system in which nanoengineered DNA vaccine was laden on microneedles (MNs) assembled with layer-by-layer coating of ultra-pH-responsive OSM-(PEG-PAEU) and immunostimulatory adjuvant poly(I:C), a synthetic double stranded RNA. Transcutaneous application of MN patches onto the mice skin perforate the stratum corneum with minimal cell damage; subsequent disassembly at the immune-cell-rich epidermis/dermis allows the release of adjuvants and DNA vaccines, owing to the ultra-sharp pH-responsive nature of OSM-(PEG-PAEU). The released adjuvant and DNA vaccine can enhance dendritic cell maturation and induce type I interferons, and thereby produce antigen-specific antibody that can achieve the antibody-dependent cell-mediated cytotoxicity (ADCC) and CD8⁺ T cell to kill cancer cells. Strikingly, transcutaneous application of smart vaccine formulation in mice elicited 3-fold greater frequencies of Anti-OVA IgG1 serum antibody and 3-fold excess of cytotoxic CD8⁺ T cell than soluble DNA vaccine formulation. As a consequence, the formulation rejected the murine B16/OVA melanoma tumors in C57BL/6 mice through the synergistic activation of antigen-specific ADCC and cytotoxic CD8⁺ T cells. The maneuvered use of vaccine and adjuvant poly(I:C) in MNs induces humoral and cellular immunity, which provides a promising vaccine technology that shows improved efficacy, compliance, and safety.

A pH- and temperature-responsive bioresorbable injectable hydrogel based on polypeptide block copolymers for the sustained delivery of proteins in vivo

A pH- and temperature-responsive in situ-forming injectable hydrogel based on comb-type polypeptide block copolymers for the controlled delivery of proteins has been developed.

Folate decorated hollow spheres of microporous organic networks as drug delivery materials

Hollow and microporous organic networks post-modified with folic acids showed promising potential as DOX delivery materials.

Poly(amino carbonate urethane)-based biodegradable, temperature and pH-sensitive injectable hydrogels for sustained human growth hormone delivery

In this study, a new pH-/temperature-sensitive, biocompatible, biodegradable, and injectable hydrogel based on poly(ethylene glycol)-poly(amino carbonate urethane) (PEG-PACU) copolymers has been developed for the sustained delivery of human growth hormone (hGH). In aqueous solutions, PEG-PACU-based copolymers existed as sols at low pH and temperature (pH 6.0, 23 °C), whereas they formed gels in the physiological condition (pH 7.4, 37 °C). The physicochemical characteristics, including gelation rate, mechanical strength and viscosity, of the PEG-PACU hydrogels could be finely tuned by varying the polymer weight, pH and temperature of the copolymer. An in vivo injectable study in the back of Sprague-Dawley (SD) rats indicated that the copolymer could form an in situ gel, which exhibited a homogenous porous structure. In addition, an in vivo biodegradation study of the PEG-PACU hydrogels showed controlled degradation of the gel matrix without inflammation at the injection site and the surrounding tissue. The hGH-loaded PEG-PACU copolymer solution readily formed a hydrogel in SD rats, which subsequently inhibited the initial hGH burst and led to the sustained release of hGH. Overall, the PEG-PACU-based copolymers prepared in this study are expected to be useful biomaterials for the sustained delivery of hGH.