pH-Responsive doxorubicin delivery using shear-thinning biomaterials for localized melanoma treatment

Development of Stimuli-Responsive Polymeric Nanomedicines in Hypoxic Tumors and Their Therapeutic Promise in Oral Cancer

Hypoxic tumors pose considerable obstacles to cancer treatment, as diminished oxygen levels can impair drug effectiveness and heighten therapeutic resistance. Oral cancer, a prevalent malignancy, encounters specific challenges owing to its intricate anatomical structure and the technical difficulties in achieving complete resection, thereby often restricting treatment efficacy. The impact of hypoxia is particularly critical in influencing both the treatment response and prognosis of oral cancers. This article summarizes and examines the potential of polymer nanomedicines to address these challenges. By engineering nanomedicines that specifically react to the hypoxic tumor microenvironment, these pharmaceuticals can markedly enhance targeting precision and therapeutic effectiveness. Polymer nanomedicines enhance therapeutic efficacy while reducing side effects by hypoxia-targeted accumulation. The article emphasizes that these nanomedicines can overcome the drug resistance frequently observed in hypoxic tumors by improving the delivery and bioavailability of anticancer agents. Furthermore, this review elucidates the design and application of polymer nanomedicines for treating hypoxic tumors, highlighting their transformative potential in cancer therapy. Finally, this article gives an outlook on stimuli-responsive polymeric nanomedicines in the treatment of oral cancer.

Drug Repurposing and Nanotechnology for Topical Skin Cancer Treatment: Redirecting toward Targeted and Synergistic Antitumor Effects

Skin cancer represents a major health concern due to its rising incidence and limited treatment options. Current treatments (surgery, chemotherapy, radiotherapy, immunotherapy, and targeted therapy) often entail high costs, patient inconvenience, significant adverse effects, and limited therapeutic efficacy. The search for novel treatment options is also marked by the high capital investment and extensive development involved in the drug discovery process. In response to these challenges, repurposing existing drugs for topical application and optimizing their delivery through nanotechnology could be the answer. This innovative strategy aims to combine the advantages of the known pharmacological background of commonly used drugs to expedite therapeutic development, with nanosystem-based formulations, which among other advantages allow for improved skin permeation and retention and overall higher therapeutic efficacy and safety. The present review provides a critical analysis of repurposed drugs such as doxycycline, itraconazole, niclosamide, simvastatin, leflunomide, metformin, and celecoxib, formulated into different nanosystems, namely, nanoemulsions and nanoemulgels, nanodispersions, solid lipid nanoparticles, nanostructured lipid carriers, polymeric nanoparticles, hybrid lipid-polymer nanoparticles, hybrid electrospun nanofibrous scaffolds, liposomes and liposomal gels, ethosomes and ethosomal gels, and aspasomes, for improved outcomes in the battle against skin cancer. Enhanced antitumor effects on melanoma and nonmelanoma research models are highlighted, with some nanoparticles even showing intrinsic anticancer properties, leading to synergistic effects. The explored research findings highly evidence the potential of these approaches to complement the currently available therapeutic strategies in the hope that these treatments might one day reach the pharmaceutical market.

Photonic control of image-guided ferroptosis cancer nanomedicine

Photonic nanomaterials, characterized by their remarkable photonic tunability, empower a diverse range of applications, including cutting-edge advances in cancer nanomedicine. Recently, ferroptosis has emerged as a promising alternative strategy for effectively killing cancer cells with minimizing therapeutic resistance. Novel design of photonic nanomaterials that can integrate photoresponsive-ferroptosis inducers, -diagnostic imaging, and -synergistic components provide significant benefits to effectively trigger local ferroptosis. This review provides a comprehensive overview of recent advancements in photonic nanomaterials for image-guided ferroptosis cancer nanomedicine, offering insights into their strengths, constraints, and their potential as a future paradigm in cancer treatment.

Drug‐Eluting Shear‐Thinning Hydrogel for the Delivery of Chemo‐ and Immunotherapeutic Agents for the Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a malignant and deadly form of liver cancer with limited treatment options. Transcatheter arterial chemoembolization, a procedure that delivers embolic and chemotherapeutic agents through blood vessels, is a promising cancer treatment strategy. However, it still faces limitations, such as inefficient agent delivery and the inability to address tumor‐induced immunosuppression. Here, a drug‐eluting shear‐thinning hydrogel (DESTH) loaded with chemotherapeutic and immunotherapeutic agents in nanocomposite hydrogels composed of gelatin and nanoclays is presented as a therapeutic strategy for a catheter‐based endovascular anticancer approach. DESTH is manually deliverable using a conventional needle and catheter. In addition, drug release studies show a sustained and pH‐dependent co‐delivery of the chemotherapy doxorubicin (acidic pH) and the immune‐checkpoint inhibitor aPD‐1 (neutral pH). In a mouse liver tumor model, the DESTH‐based chemo/immunotherapy combination has the highest survival rate and smallest residual tumor size. Finally, immunofluorescence analysis confirms that DESTH application enhances cell death and increases intratumoral infiltration of cytotoxic T‐cells. In conclusion, the results show that DESTH, which enables efficient ischemic tumor cell death and effective co‐delivery of chemo‐ and immunotherapeutic agents, may have the potential to be an effective therapeutic modality in the treatment of HCC.

Magnetic nanoparticles for ferroptosis cancer therapy with diagnostic imaging

Ferroptosis offers a novel method for overcoming therapeutic resistance of cancers to conventional cancer treatment regimens. Its effective use as a cancer therapy requires a precisely targeted approach, which can be facilitated by using nanoparticles and nanomedicine, and their use to enhance ferroptosis is indeed a growing area of research. While a few review papers have been published on iron-dependent mechanism and inducers of ferroptosis cancer therapy that partly covers ferroptosis nanoparticles, there is a need for a comprehensive review focusing on the design of magnetic nanoparticles that can typically supply iron ions to promote ferroptosis and simultaneously enable targeted ferroptosis cancer nanomedicine. Furthermore, magnetic nanoparticles can locally induce ferroptosis and combinational ferroptosis with diagnostic magnetic resonance imaging (MRI). The use of remotely controllable magnetic nanocarriers can offer highly effective localized image-guided ferroptosis cancer nanomedicine. Here, recent developments in magnetically manipulable nanocarriers for ferroptosis cancer nanomedicine with medical imaging are summarized. This review also highlights the advantages of current state-of-the-art image-guided ferroptosis cancer nanomedicine. Finally, image guided combinational ferroptosis cancer therapy with conventional apoptosis-based therapy that enables synergistic tumor therapy is discussed for clinical translations.

Injectable Nanoengineered Adhesive Hydrogel for Treating Enterocutaneous Fistulas

Enterocutaneous fistula (ECF) is a severe medical condition where an abnormal connection forms between the gastrointestinal tract and skin. ECFs are, in most cases, a result of surgical complications such as missed enterotomies or anastomotic leaks. The constant leakage of enteric and fecal contents from the fistula site leads to skin breakdown and increases the risk of infection. Despite advances in surgical techniques and postoperative management, ECF accounts for significant mortality rates, estimated between 15-20%, and causes debilitating morbidity. Therefore, there is a critical need for a simple and effective method to seal and heal ECF. Injectable hydrogels with combined properties of robust mechanical properties and cell infiltration/proliferation have the potential to block and heal ECF. Herein, we report the development of an injectable nanoengineered adhesive hydrogel (INAH) composed of a synthetic nanosilicate (Laponite®) and a gelatin-dopamine conjugate for treating ECF. The hydrogel undergoes fast cross-linking using a co-injection method, resulting in a matrix with improved mechanical and adhesive properties. INAH demonstrates appreciable blood clotting abilities and is cytocompatible with fibroblasts. The adhesive properties of the hydrogel are demonstrated in ex vivo adhesion models with skin and arteries, where the volume stability in the hydrated internal environment facilitates maintaining strong adhesion. In vivo assessments reveal that the INAH is biocompatible, supporting cell infiltration and extracellular matrix deposition while not forming fibrotic tissue. These findings suggest that this INAH holds promising translational potential for sealing and healing ECF.

Injectable Shear-Thinning Hydrogels with Sclerosing and Matrix Metalloproteinase Modulatory Properties for the Treatment of Vascular Malformations

Sac embolization of abdominal aortic aneurysms (AAAs) remains clinically limited by endoleak recurrences. These recurrences are correlated with recanalization due to the presence of endothelial lining and matrix metalloproteinases (MMPs)-mediated aneurysm progression. This study incorporated doxycycline (DOX), a well-known sclerosant and MMPs inhibitor, into a shear-thinning biomaterial (STB)-based vascular embolizing hydrogel. The addition of DOX was expected to improve embolizing efficacy while preventing endoleaks by inhibiting MMP activity and promoting endothelial removal. The results showed that STBs containing 4.5% w/w silicate nanoplatelet and 0.3% w/v of DOX were injectable and had a 2-fold increase in storage modulus compared to those without DOX. STB-DOX hydrogels also reduced clotting time by 33% compared to untreated blood. The burst release of DOX from the hydrogels showed sclerosing effects after 6 h in an ex vivo pig aorta model. Sustained release of DOX from hydrogels on endothelial cells showed MMP inhibition (ca. an order of magnitude larger than control groups) after 7 days. The hydrogels successfully occluded a patient-derived abdominal aneurysm model at physiological blood pressures and flow rates. The sclerosing and MMP inhibition characteristics in the engineered multifunctional STB-DOX hydrogels may provide promising opportunities for the efficient embolization of aneurysms in blood vessels.

Nanocrystals Slow-Releasing Ropivacaine and Doxorubicin to Synergistically Suppress Tumor Recurrence and Relieve Postoperative Pain

Although surgical resection provides a straightforward and effective treatment for most malignant solid tumors, tumor recurrence and acute postoperative pain continue to be two big problems associated with this treatment. To resolve these problems, a nanocrystal composite slow-releasing ropivacaine and doxorubicin was fabricated in this study. Briefly, a self-assembling peptide was used to form nanoparticle complexes with the two drugs, based on which homogeneous nanocrystals were obtained by adjusting the pH. In cultured human melanoma cells, the nanocrystals exhibited improved antitumor activity due to a synergistic effect and enhanced cellular uptake of the two drugs. On the other hand, the nanocrystals could slowly release ropivacaine in vitro and in vivo, generating long-acting analgesia on the rat sciatic nerve block model and incisional pain model. On a nude mouse tumor resection model, the nanocrystals simultaneously suppressed the recurrence of solid tumor and relieved postoperative pain, indicating a potential postoperative treatment for tumor resection patients. This nanocrystal system also suggested a promising and facile strategy for developing multifunctional formulations combining different drugs, which could achieve better therapeutic outcomes in a synergistic and sustained manner.

Gelatin methacryloyl and Laponite bioink for 3D bioprinted organotypic tumor modeling

Three-dimensional (3D)in vitrotumor models that can capture the pathophysiology of human tumors are essential for cancer biology and drug development. However, simulating the tumor microenvironment is still challenging because it consists of a heterogeneous mixture of various cellular components and biological factors. In this regard, current extracellular matrix (ECM)-mimicking hydrogels used in tumor tissue engineering lack physical interactions that can keep biological factors released by encapsulated cells within the hydrogel and improve paracrine interactions. Here, we developed a nanoengineered ion-covalent cross-linkable bioink to construct 3D bioprinted organotypic tumor models. The bioink was designed to implement the tumor ECM by creating an interpenetrating network composed of gelatin methacryloyl (GelMA), a light cross-linkable polymer, and synthetic nanosilicate (Laponite) that exhibits a unique ionic charge to improve retention of biological factors released by the encapsulated cells and assist in paracrine signals. The physical properties related to printability were evaluated to analyze the effect of Laponite hydrogel on bioink. Low GelMA (5%) with high Laponite (2.5%-3.5%) composite hydrogels and high GelMA (10%) with low Laponite (1.0%-2.0%) composite hydrogels showed acceptable mechanical properties for 3D printing. However, a low GelMA composite hydrogel with a high Laponite content could not provide acceptable cell viability. Fluorescent cell labeling studies showed that as the proportion of Laponite increased, the cells became more aggregated to form larger 3D tumor structures. Reverse transcription-polymerase chain reaction (RT-qPCR) and western blot experiments showed that an increase in the Laponite ratio induces upregulation of growth factor and tissue remodeling-related genes and proteins in tumor cells. In contrast, cell cycle and proliferation-related genes were downregulated. On the other hand, concerning fibroblasts, the increase in the Laponite ratio indicated an overall upregulation of the mesenchymal phenotype-related genes and proteins. Our study may provide a rationale for using Laponite-based hydrogels in 3D cancer modeling.

Mussel-Inspired Adhesive Hydrogels Based on Laponite-Confined Dopamine Polymerization as a Transdermal Patch

Transdermal patch for local drug delivery has attained huge attention as an attractive alternative to existing drug delivery techniques as it is painless and user-friendly. However, most adhesive hydrogels either do not have adequate adhesion with the skin or cause discomfort while being removed from the skin surface due to excessive adhesion. To address this challenge, we developed an adhesive hydrogel based on laponite-confined dopamine polymerization as a transdermal patch. Laponite RDS nanoclay was used to control the hydrogel's viscous behavior and dopamine polymerization. The laponite polymerized polydopamine (l-PDA) was incorporated into poly(vinyl alcohol) (PVA) to make the PVA-l-PDA hydrogel. The laponite-confined polymerization improved the hydrogels' water contact angle and adhesion strength. The adhesion strength of the PVA-l-PDA hydrogel was adequate to adhere to the evaluated goat skin, glass, and polypropylene surfaces. Notably, the PVA-l-PDA hydrogel was easy to peel off from the skin. Further, we evaluated the drug release profile in goat skin using lidocaine as a model drug. We observed the controlled release of lidocaine from the PVA-l-PDA hydrogel compared to the PVA-PDA hydrogel. In addition, the nanoclay-confined adhesive hydrogel did not show any cytotoxic effect in fibroblasts. Altogether, PVA-l-PDA hydrogels offer appropriate adhesive strength, toughness, and biocompatibility. Thus, the PVA-l-PDA hydrogel has the potential to be an efficient transdermal patch.

Thermoresponsive shear-thinning hydrogel (T-STH) hemostats for minimally invasive treatment of external hemorrhages

Hemorrhage is the leading cause of death following battlefield injuries. Although several hemostats are commercially available, they do not meet all the necessary requirements to stop bleeding in combat injuries. Here, we engineer thermoresponsive shear-thinning hydrogels (T-STH) composed of a thermoresponsive polymer, poly(N-isopropyl acrylamide) (p(NIPAM)), and hemostatic silicate nanodisks, LAPONITE®, as minimally invasive injectable hemostatic agents. Our T-STH is a physiologically stable hydrogel that can be easily injected through a syringe and needle and exhibits rapid mechanical recovery. Additionally, it demonstrates temperature-dependent blood coagulation owing to the phase transition of p(NIPAM). It decreases in vitro blood clotting times over 50% at physiological temperatures compared to room temperature. Furthermore, it significantly prevents blood loss in an ex vivo bleeding model at different blood flow rates (1 mL min^-1 and 5 mL min^-1) by forming a wound plug. More importantly, our T-STH is comparable to a commercially available hemostat, Floseal, in terms of blood loss and blood clotting time in an in vivo rat liver bleeding model. Furthermore, once the hemorrhage is stabilized, our T-STH can be easily removed using a cold saline wash without any rebleeding or leaving any residues. Taken together, our T-STH can be used as a first aid hemostat to treat external hemorrhages in emergency situations.

Sodium Phytate-Incorporated Gelatin-Silicate Nanoplatelet Composites for Enhanced Cohesion and Hemostatic Function of Shear-Thinning Biomaterials

Shear-thinning biomaterials (STBs) based on gelatin-silicate nanoplatelets (SNs) are emerging as an alternative to conventional coiling and clipping techniques in the treatment of vascular anomalies. Improvements in the cohesion of STB hydrogels pave the way toward their translational application in minimally invasive therapies such as endovascular embolization repair. In the present study, sodium phytate (Phyt) additives are used to tune the electrostatic network of SNs-gelatin STBs, thereby promoting their mechanical integrity and facilitating injectability through standard catheters. We show that an optimized amount of Phyt enhances storage modulus by approximately one order of magnitude and reduces injection force by ≈58% without compromising biocompatibility and hydrogel wet stability. The Phyt additives are found to decrease the immune responses induced by SNs. In vitro embolization experiments suggest a significantly lower rate of failure in Phyt-incorporated STBs than in control groups. Furthermore, the addition of Phyt leads to accelerated blood coagulation (reduces clotting time by ≈45% compared to controls) due to the contributions of negatively charged phosphate groups, which aid in the prolonged durability of STB in coagulopathic patients. Therefore, the proposed approach is an effective method for the design of robust and injectable STBs for minimally invasive treatment of vascular malformations.

Locally controlled release of immunosuppressive promotes survival of transplanted adult spinal cord tissue

Transplantation of adult spinal cord tissue (aSCT) is a promising treatment for spinal cord injury (SCI) basing on various types of neural cells and matrix components inside aSCT. However, long-term systemic administration of immunosuppressors (e.g. tacrolimus, TAC) is required for the survival of allogeneic tissue, which often associated with severe side effects such as infection, liver damageand renal failure. In this study, a triglycerol monostearate (TGM)-based TAC delivery system (e.g. TAC@TGM) with high drug loading concentration was developed, which possessed injectable properties as well as sustainable and immune-responsive drug release behaviors. In complete transected SCI model, locally injected TAC@TGM could reduce the infiltration of inflammation cells, enhance the survival of transplanted aSCT (e.g. Tuj-1⁺ and NF⁺ neurons) and promote the recovery of locomotor function. Moreover, controlled release of TAC by TAC@TGM attenuated side effects of TAC on liver and kidneys compared with traditional systemic administration. More importantly, the developed TAC@TGM system provided a facile single dose of long-term immunosuppressive effect not just for aSCT transplantation, but also for other tissue/organ and cell transplantations.

Advances in the Application of Nanomaterials to the Treatment of Melanoma

Melanoma can be divided into cutaneous melanoma, uveal melanoma, mucosal melanoma, etc. It is a very aggressive tumor that is prone to metastasis. Patients with metastatic melanoma have a poor prognosis and shorter survival. Although current melanoma treatments have been dramatically improved, there are still many problems such as systemic toxicity and the off-target effects of drugs. The use of nanoparticles may overcome some inadequacies of current melanoma treatments. In this review, we summarize the limitations of current therapies for cutaneous melanoma, uveal melanoma, and mucosal melanoma, as well as the adjunct role of nanoparticles in different treatment modalities. We suggest that nanomaterials may have an effective intervention in melanoma treatment in the future.