Recent advances in hydrogels for preventing tumor recurrence

In-situ-formed immunotherapeutic and hemostatic dual drug-loaded nanohydrogel for preventing postoperative recurrence of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent malignancy characterized by an exceedingly high recurrence rate post-surgery, significantly impairing the prognosis of HCC patients. However, a standard in-care strategy for postoperative therapy is still lacking. Although encouraging results have been obtained in a newly published clinical trial for postoperative therapy by targeting the vascular endothelial growth factor (VEGF) and programmed death ligand 1 (anti-PD-L1), its efficacy remains constrained. Combining a hemostatic hydrogel with a nanoparticle-based drug delivery system presents an opportunity to optimize the antitumor effect. Herein, we developed a nanoplatform, termed HMSN@Sor/aP@Gel, comprising a hemostatic fibrin hydrogel and functionalized hollow mesoporous silica nanoparticles (HMSNs) loaded with sorafenib and anti-PD-L1 for locally administered targeted-immunotherapy to prevent the postoperative recurrence and metastasis of HCC. The antitumor mechanism is grounded in dual inhibition of Ras/Raf/MEK/ERK (MAPK) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) pathways, synergistically complemented by PD-L1 blockade. HMSN@Sor/aP@Gel facilitates dendritic cell maturation, enhances cytotoxic T-lymphocyte infiltration, promotes the polarization of tumor-associated macrophages to M1 phenotype, induces tumor immunogenic cell death, reverses immunosuppression, and establishes immune memory to counter postoperative recurrence. Animal studies corroborate that HMSN@Sor/aP@Gel-mediated targeted immunotherapy significantly impedes primary and metastatic tumor growth and establishes immune memory to prevent recurrence post-surgery. This investigation presents a promising strategy for postoperative therapy with considerable potential for clinical translation.

Multifunctional hydrogels based on photothermal therapy: A prospective platform for the postoperative management of melanoma

Preventing the recurrence of melanoma after surgery and accelerating wound healing are among the most challenging aspects of melanoma management. Photothermal therapy has been widely used to treat tumors and bacterial infections and promote wound healing. Owing to its efficacy and specificity, it may be used for postoperative management of tumors. However, its use is limited by the uncontrollable distribution of photosensitizers and the likelihood of damage to the surrounding normal tissue. Hydrogels provide a moist environment with strong biocompatibility and adhesion for wound healing owing to their highly hydrophilic three-dimensional network structure. In addition, these materials serve as excellent drug carriers for tumor treatment and wound healing. It is possible to combine the advantages of both of these agents through different loading modalities to provide a powerful platform for the prevention of tumor recurrence and wound healing. This review summarizes the design strategies, research progress and mechanism of action of hydrogels used in photothermal therapy and discusses their role in preventing tumor recurrence and accelerating wound healing. These findings provide valuable insights into the postoperative management of melanoma and may guide the development of promising multifunctional hydrogels for photothermal therapy.

Enteromorpha Prolifera Polysaccharide-Derived Injectable Hydrogel for Fast Intraoperative Hemostasis and Accelerated Postsurgical Wound Healing Following Tumor Resection

Intraoperative bleeding and delayed postsurgical wound healing caused by persistent inflammation can increase the risk of tumor recurrence after surgical resection. To address these issues, Enteromorpha prolifera polysaccharide (PEP) with intrinsic potentials for hemostasis and wound healing, is chemically modified into aldehyde-PEP and hydrazine-PEP. Thereby, an injectable double-network hydrogel (OPAB) is developed via forming dual dynamic bonding of acylhydrazone bonds between the decorated aldehyde and hydrazine groups and hydrogen bonds between hydroxyl groups between boric acid and PEP skeletons. The OPAB exhibits controllable shape-adaptive gelation (35.0 s), suitable mechanical properties, nonstimulating self-healing (60 s), good wet tissue adhesion (30.9 kPa), and pH-responsive biodegradability. For in vivo models, owing to these properties, OPAB can achieve rapid hemostasis within 30 s for the liver hemorrhage, and readily loading of curcumin nanoparticles to remarkably accelerate surgical wound closure by alleviating inflammation, re-epithelialization, granulation tissue formation, and collagen deposition. Overall, this multifunctional injectable hydrogel is a promising material that facilitates simultaneous intraoperative hemorrhage and postsurgical wound repair, holding significant potential in the clinical managements of bleeding and surgical wounds for tumor resection.

Albumin hydrogels for repeated capture of drugs from the bloodstream and release into the tumor

Despite the efficacy of hydrogels for consistently delivering drugs to targeted areas (primarily tumors), these systems face challenges such as initial burst release, non-refillable drugs, and a lack of dosage control. To address these issues, a novel strategy has been developed to capture and release drugs from the bloodstream, thereby overcoming the limitations of traditional hydrogels. In this study, an innovative albumin hydrogel system was developed through a bioorthogonal reaction using azide-modified albumin and 4-arm PEG-DBCO. This system can repeatedly capture and release drugs over prolonged periods. Inspired by albumin-drug binding in vivo, this hydrogel can be injected intratumorally and acts as a reservoir for capturing drugs circulating in the bloodstream. Drugs captured in hydrogels are released slowly and effectively delivered to tumors through a "capture and release process." Both the in vitro and in vivo results indicated that the hydrogel effectively captured and released drugs, such as indocyanine green and doxorubicin, over repeated cycles without compromising the activity of the drugs. Moreover, implanting the hydrogel at surgical sites successfully inhibited tumor recurrence through its drug capture-release capability. These findings establish the albumin hydrogel system as a promising capture-release platform that leverages drug-binding affinity to effectively deliver drugs to tumors, offering potential advancements in cancer treatment and post-surgery recurrence prevention.

Chitosan Hydrogel-Delivered ABE8e Corrects PAX9 Mutant in Dental Pulp Stem Cells

Hypodontia (dental agenesis) is a genetic disorder, and it has been identified that the mutation C175T in PAX9 could lead to hypodontia. Cas9 nickase (nCas9)-mediated homology-directed repair (HDR) and base editing were used for the correction of this mutated point. This study aimed to investigate the effect of HDR and the base editor ABE8e in editing PAX9 mutant. It was found that the chitosan hydrogel was efficient in delivering naked DNA into dental pulp stem cells (DPSCs). To explore the influence of the C175T mutation in PAX9 on the proliferation of DPSCs, hydrogel was employed to deliver PAX9 mutant vector into DPSCs, finding that the PAX9-containing C175T mutation failed to promote the proliferation of DPSCs. Firstly, DPSCs stably carrying PAX9 mutant were constructed. Either an HDR or ABE8e system was delivered into the above-mentioned stable DPSCs, and then the correction efficiency using Sanger sequencing and Western blotting was determined. Meanwhile, the ABE8e presented significantly higher efficiency in correcting C175T compared with HDR. Furthermore, the corrected PAX9 presented enhanced viability and differentiation capacity for osteogenic and neurogenic lineages; the corrected PAX9 even possessed extremely enhanced transcriptional activation ability. In summary, this study has powerful implications for studies into base editors, chitosan hydrogel, and DPSCs in treating hypodontia.