Injectable small molecule hydrogel as a potential nanocarrier for localized and sustained in vivo delivery of doxorubicin

Peptide-functionalized, -assembled and -loaded nanoparticles in cancer therapy

The combination of peptides and nanoparticles in cancer therapy has shown synergistic results. Nanoparticle functionalization with peptides can increase their targeting ability towards tumor cells. In some cases, the peptides can develop self-assembled nanoparticles, in combination with drugs, for targeted cancer therapy. The peptides can be loaded into nanoparticles and can be delivered by other drugs for synergistic cancer removal. Multifunctional types of peptide-based nanoparticles, including pH- and redox-sensitive classes, have been introduced in cancer therapy. The tumor microenvironment remolds, and the acceleration of immunotherapy and vaccines can be provided by peptide nanoparticles. Moreover, the bioimaging and labeling of cancers can be mediated by peptide nanoparticles. Therefore, peptides can functionalize nanoparticles in targeted cancer therapy.

Recent Advances in Smart Self-Assembled Bioinspired Hydrogels: A Bridging Weapon for Emerging Health Care Applications from Bench to Bedside

Stimuli-responsive low molecular weight hydrogel interventions for Biomedical challenges are a rapidly evolving paradigm in the bottom-up approach recently. Peptide-based self-assembled nano biomaterials present safer alternatives to their non-degradable counterparts as demanded for today's most urged clinical needs.Although a plethora of work has already been accomplished, programming hydrogelators with appropriate functionalities requires a better understanding as the impact of the macromolecular structure of the peptides and subsequently, their self-assembled nanostructures remain unidentified. Henceforth this review focuses on two aspects: Firstly, the underlying guidelines for building biomimetic strategies to tailor scaffolds leading to hydrogelation along with the role of non-covalent interactions that are the key components of various self-assembly processes. In the second section, it is aimed to bring together the recent achievements with designer assembly concerning their self-aggregation behaviour and applications mainly in the biomedical arena like drug delivery carrier design, antimicrobial, anti-inflammatory as well as wound healing materials. Furthermore, it is anticipated that this article will provide a conceptual demonstration of the different approaches taken towards the construction of these task-specific designer hydrogels. Finally, a collective effort among the material scientists is required to pave the path for the entrance of these intelligent materials into medicine from bench to bedside.

Coiled-Coil Protein Hydrogels Engineered with Minimized Fiber Diameters for Sustained Release of Doxorubicin in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) lacks expressed protein targets, making therapy development challenging. Hydrogels offer a promising new route in this regard by improving the chemotherapeutic efficacy through increased solubility and sustained release. Moreover, subcutaneous hydrogel administration reduces patient burden by requiring less therapy and shorter treatment times. We recently established the design principles for the supramolecular assembly of single-domain coiled-coils into hydrogels. Using a modified computational design algorithm, we designed Q8, a hydrogel with rapid assembly for faster therapeutic hydrogel preparation. Q8 encapsulates and releases doxorubicin (Dox), enabling localized sustained release via subcutaneous injection. Remarkably, a single subcutaneous injection of Dox-laden Q8 (Q8•Dox) significantly suppresses tumors within just 1 week. This work showcases the bottom-up engineering of a fully protein-based drug delivery vehicle for improved TBNC treatment via noninvasive localized therapy.

Peptide Self-Assembled Nanocarriers for Cancer Drug Delivery

The design of novel cancer drug nanocarriers is critical in the framework of cancer therapeutics. Nanomaterials are gaining increased interest as cancer drug delivery systems. Self-assembling peptides constitute an emerging novel class of highly attractive nanomaterials with highly promising applications in drug delivery, as they can be used to facilitate drug release and/or stability while reducing side effects. Here, we provide a perspective on peptide self-assembled nanocarriers for cancer drug delivery and highlight the aspects of metal coordination, structure stabilization, and cyclization, as well as minimalism. We review particular challenges in nanomedicine design criteria and, finally, provide future perspectives on addressing a portion of the challenges via self-assembling peptide systems. We consider that the intrinsic advantages of such systems, along with the increasing progress in computational and experimental approaches for their study and design, could possibly lead to novel classes of single or multicomponent systems incorporating such materials for cancer drug delivery.

Self-Assembly, Bioactivity, and Nanomaterials Applications of Peptide Conjugates with Bulky Aromatic Terminal Groups

The self-assembly and structural and functional properties of peptide conjugates containing bulky terminal aromatic substituents are reviewed with a particular focus on bioactivity. Terminal moieties include Fmoc [fluorenylmethyloxycarbonyl], naphthalene, pyrene, naproxen, diimides of naphthalene or pyrene, and others. These provide a driving force for self-assembly due to π-stacking and hydrophobic interactions, in addition to the hydrogen bonding, electrostatic, and other forces between short peptides. The balance of these interactions leads to a propensity to self-assembly, even for conjugates to single amino acids. The hybrid molecules often form hydrogels built from a network of β-sheet fibrils. The properties of these as biomaterials to support cell culture, or in the development of molecules that can assemble in cells (in response to cellular enzymes, or otherwise) with a range of fascinating bioactivities such as anticancer or antimicrobial activity, are highlighted. In addition, applications of hydrogels as slow-release drug delivery systems and in catalysis and other applications are discussed. The aromatic nature of the substituents also provides a diversity of interesting optoelectronic properties that have been demonstrated in the literature, and an overview of this is also provided. Also discussed are coassembly and enzyme-instructed self-assembly which enable precise tuning and (stimulus-responsive) functionalization of peptide nanostructures.

Switching the Mode of Drug Release from a Reaction-Coupled Low-Molecular-Weight Gelator System by Altering Its Reaction Pathway

Low-molecular-weight hydrogels are attractive scaffolds for drug delivery applications because of their modular and facile preparation starting from inexpensive molecular components. The molecular design of the hydrogelator results in a commitment to a particular release strategy, where either noncovalent or covalent bonding of the drug molecule dictates its rate and mechanism. Herein, we demonstrate an alternative approach using a reaction-coupled gelator to tune drug release in a facile and user-defined manner by altering the reaction pathway of the low-molecular-weight gelator (LMWG) and drug components through an acylhydrazone-bond-forming reaction. We show that an off-the-shelf drug with a reactive handle, doxorubicin, can be covalently bound to the gelator through its ketone moiety when the addition of the aldehyde component is delayed from 0 to 24 h, or noncovalently bound with its addition at 0 h. We also examine the use of an l-histidine methyl ester catalyst to prepare the drug-loaded hydrogels under physiological conditions. Fitting of the drug release profiles with the Korsmeyer-Peppas model corroborates a switch in the mode of release consistent with the reaction pathway taken: increased covalent ligation drives a transition from a Fickian to a semi-Fickian mode in the second stage of release with a decreased rate. Sustained release of doxorubicin from the reaction-coupled hydrogel is further confirmed in an MTT toxicity assay with MCF-7 breast cancer cells. We demonstrate the modularity and ease of the reaction-coupled approach to prepare drug-loaded self-assembled hydrogels in situ with tunable mechanics and drug release profiles that may find eventual applications in macroscale drug delivery.

Development of nanoparticle loaded microneedles for drug delivery to a brain tumour resection site

Systemic drug delivery to the central nervous system (CNS) has been historically impeded by the presence of the blood brain barrier rendering many therapies inefficacious to any cancer cells residing within the brain. Therefore, local drug delivery systems are being developed to overcome this shortfall. Here we have manufactured polymeric microneedle (MN) patches, which can be anchored within a resection cavity site following surgical removal of a tumour such as isocitrate dehydrogenase wild type glioblastoma (GBM). These MN patches have been loaded with polymer coated nanoparticles (NPs) containing cannabidiol (CBD) or olaparib (OLA) and applied to an in vitro brain simulant and ex vivo rat brain tissue to assess drug release and distance of penetration. MN patches loaded with methylene blue dye were placed into a cavity of 0.6 % agarose to simulate brain tissue. The results showed that clear channels were generated by the MNs and the dye spread laterally throughout the agarose. When loaded with CBD-NPs, the agarose showed a CBD concentration of 12.5 µg/g at 0.5 cm from the MN insertion site. Furthermore, high performance liquid chromatography of ex vivo brain tissue following CBD-NP/MN patch insertion showed successful delivery of 59.6 µg/g into the brain tissue. Similarly, OLA-NP loaded MN patches showed delivery of 5.2 µg/g OLA into agarose gel at 0.5 cm distance from the insertion site. Orbitrap secondary ion mass spectrometry (OrbiSIMS) analysis confirmed the presence of OLA and the MN patch at up to 6 mm away from the insertion site following its application to a rat brain hemisphere. This data has provided insight into the capabilities and versatility of MN patches for use in local brain drug delivery, giving promise for future research.

Anion-responsive self-assembled hydrogels of a phenylalanine-TREN conjugate allow sequential release of propranolol and doxorubicin

Stimuli-responsive self-assembled and supramolecular hydrogels derived from peptide amphiphiles have opened exciting new avenues in biomedicine and drug delivery. Herein, we screened a series of phenylalanine-amphiphiles possessing polyamine and oxyethylene appendages for their self-assembly and anion-responsiveness and found that the tris(aminoethyl)amine (TREN) containing amphiphile NapF-TREN formed injectable hydrogels that could be disrupted upon the addition of stoichiometric amounts of tetrahedral monovalent anions such as H₂PO₄^- and HSO₄^-, while the addition of other anions such as Cl^-, HPO₄^2-, CO₃^2-, HCO₃^- or SO₄^2- did not affect the gel stability. The anion-gelator interaction was investigated by ¹H and ³¹P NMR spectroscopy as well as by Isothermal Titration Calorimetry (ITC). These studies confirmed a 1 : 1 stoichiometry and revealed negative enthalpy and negative entropy for the binding of H₂PO₄^- with NapF-TREN. Microscopic investigations by TEM, AFM, and SAXS revealed that H₂PO₄^- anions induced a nanofiber-to-nanoglobule morphological change in the aqueous self-assemblies of NapF-TREN. However, upon ageing the samples, slow reformation of the nanofibers was also observed, reflecting the reversibility of the anion-gelator interaction. The anion- and pH-responsive nature of the NapF-TREN hydrogels was exploited to program sequential release of entrapped drugs propranolol and doxorubicin.

Tumor-oriented mathematical models in hydrogel regulation for precise topical administration regimens

Increasing knowledge of drug delivery properties, tumor profiles and their relationship promotes precise administration regimens, representing a promising pattern to personalized tumor treatment. Herein, we propose a regulatory hydrogel depot toward metastatic cancer by establishing mathematical models between tumor characteristics and administration regimens. Specifically, a thermo-sensitive PLGA-PEG-PLGA polymer is introduced as injectable hydrogel matrix, of which the administration volume and frequency are manipulated elaborately according to tumor size and gel-degradation kinetics. Structurally, doxorubicin (Dox) and arginine-terminated nanoparticles containing KIAA1199 specific shRNA (^shKIAARPDNs) are incorporated into hydrogels, thereby formulating a topical and sustained drug depot to achieve synergy treatment. For dual-targeting therapy, Dox interdicts DNA replication/transcription, and shKIAA persistently silences KIAA1199 protein to modulate aggressive phenotypes. After individual peritumoral injection, Gel/^shKIAARPDNs/Dox demonstrates desirable distribution patterns and gel degradation kinetics with enhanced tumor penetration. Moreover, a preferable inhibition of tumor proliferation and metastasis is confirmed after twice treatment in 12 days, indicating better therapeutic efficacy with less dosage and frequency. Consequently, the controllable administration regimen inspired mathematical models of thermosensitive hydrogel provides an intelligent platform for personalized treatment to metastatic cancer.

Dynamic covalent hydrogel of natural product baicalin with antibacterial activities

Baicalin has been demonstrated to have multiple pharmacological activities but low solubility. Various baicalin hydrogels have been used to improve its solubility and break its limitation in clinical applications. However, traditional baicalin hydrogels contain numerous ingredients and usually show low baicalin loading capacity. Herein, we discovered a dynamic covalent hydrogel only consisting of baicalin and inorganic borate, in which baicalin is considered as the carrier and drug without other ingredients. The dynamic boronate bonds endow the hydrogel with excellent degradability and multi-stimuli-responsiveness. Moreover, the hydrogel displayed remarkable thixotropy, moldability, and self-healing properties. And the biocompatible baicalin hydrogel exhibited significant antibacterial activities, and can be considered as a potential drug delivery system for biomedical applications.

Recent Advances in the Local Drug Delivery Systems for Improvement of Anticancer Therapy

The conventional anticancer chemotherapies not only cause serious toxic effects, but also produce resistance in tumor cells exposed to long-term therapy. Usually, the killing of metastasized cancer cells requires long-term therapy with higher drug doses, because the cancer cells develop resistance due to the induction of poly-glycoproteins (P-gps) that act as a transmembrane efflux pump to transport drugs out of the cells. During the last few decades, scientists have been exploring new anticancer drug delivery systems such as microencapsulation, hydrogels, and nanotubes to improve bioavailability, reduce drug-dose requirement, decrease multiple drug resistance, and to save normal cells as non-specific targets. Hopefully, the development of novel drug delivery vehicles (nanotubes, liposomes, supramolecules, hydrogels, and micelles) will assist to deliver drug molecules at the specific target site and reduce the undesirable side effects of anticancer therapies in humans. Nanoparticles and lipid formulations are also designed to deliver small drug payload at the desired tumor cell sites for their anticancer actions. This review will focus on the recent advances in the drug delivery systems, and their application in treating different cancer types in humans.

Biomaterials and Adipose-Derived Mesenchymal Stem Cells for Regenerative Medicine: A Systematic Review

The use of biological templates for the suitable growth of adipose-derived mesenchymal stem cells (AD-MSC) and “neo-tissue” construction has exponentially increased over the last years. The bioengineered scaffolds still have a prominent and biocompatible framework playing a role in tissue regeneration. In order to supply AD-MSCs, biomaterials, as the stem cell niche, are more often supplemented by or stimulate molecular signals that allow differentiation events into several strains, besides their secretion of cytokines and effects of immunomodulation. This systematic review aims to highlight the details of the integration of several types of biomaterials used in association with AD-MSCs, collecting notorious and basic data of in vitro and in vivo assays, taking into account the relevance of the interference of the cell lineage origin and handling cell line protocols for both the replacement and repairing of damaged tissues or organs in clinical application. Our group analyzed the quality and results of the 98 articles selected from PubMed, Scopus and Web of Science. A total of 97% of the articles retrieved demonstrated the potential in clinical applications. The synthetic polymers were the most used biomaterials associated with AD-MSCs and almost half of the selected articles were applied on bone regeneration.

Isoform-Specific Properties of Orai Homologues in Activation, Downstream Signaling, Physiology and Pathophysiology

Ca2+ ion channels are critical in a variety of physiological events, including cell growth, differentiation, gene transcription and apoptosis. One such essential entry pathway for calcium into the cell is the Ca2+ release-activated Ca2+ (CRAC) channel. It consists of the Ca2+ sensing protein, stromal interaction molecule 1 (STIM1) located in the endoplasmic reticulum (ER) and a Ca2+ ion channel Orai in the plasma membrane. The Orai channel family includes three homologues Orai1, Orai2 and Orai3. While Orai1 is the "classical" Ca2+ ion channel within the CRAC channel complex and plays a universal role in the human body, there is increasing evidence that Orai2 and Orai3 are important in specific physiological and pathophysiological processes. This makes them an attractive target in drug discovery, but requires a detailed understanding of the three Orai channels and, in particular, their differences. Orai channel activation is initiated via Ca2+ store depletion, which is sensed by STIM1 proteins, and induces their conformational change and oligomerization. Upon STIM1 coupling, Orai channels activate to allow Ca2+ permeation into the cell. While this activation mechanism is comparable among the isoforms, they differ by a number of functional and structural properties due to non-conserved regions in their sequences. In this review, we summarize the knowledge as well as open questions in our current understanding of the three isoforms in terms of their structure/function relationship, downstream signaling and physiology as well as pathophysiology.

Does local drug delivery still hold therapeutic promise for brain cancer? A systematic review

BACKGROUND

Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults. Despite the gold standard treatment combining surgical resection, radiation and adjuvant plus concomitant chemotherapy with the alkylating agent temozolomide (TMZ), the prognosis remains poor (5-year survival rate < 10%). Over the last three decades, a vast array of drug delivery systems (DDS) have been developed for the local treatment of GBM, with the majority of the characterization being undertaken in pre-clinical models. We aimed to gain an overview of the potential efficacy of such local delivery systems in comparison to the systemic drug administration.

METHODS

In this paper, a systematic search of Pubmed, Web of Science, and Scopus was performed using pre-determined search terms. Studies were assessed for eligibility based on specific inclusion and exclusion criteria. A total of fifteen publications were included for analysis of local vs systemic group median survival, tumor volume and adverse events, with five brought forward for a meta-analysis.

RESULTS

The majority of studies showed local delivery to be more efficacious than systemic administration, regardless of the drug, animal model, type of DDS used, or duration of the study. The meta-analysis also showed that the mean difference between median survival ratios was statistically significantly in favor of local delivery.

CONCLUSION

Preclinical evidence shows that there is a firm rationale for further developing DDS for local therapeutic delivery to GBM and other brain cancers.

Advances in engineering of low molecular weight hydrogels for chemotherapeutic applications

Chemotherapy is the primary option for the treatment of cancer, inflammation, and infectious diseases. Conventional drug delivery poses solubility and bioavailability challenges, systemic toxicity, non-specific targeting, and poor accumulation of chemotherapeutic drugs at the desired site. Nanotechnology has led to the development of various nanomaterials that have decreased the toxicity and increased the accumulation of drugs at the target site. Systemic administration of nanomaterials causes burst release and non-specific targeting of chemotherapeutics, leading to off-target organ toxicity. Drug delivery based on low molecular weight hydrogels (LMWHs) provides a suitable alternative for drug delivery due to their ability to entrap chemotherapeutic drugs. Injectable and biodegradable LMWHs allow the administration of chemotherapeutics with minimal invasion, allow the sustained release of chemotherapeutic drugs for long periods, and reduce the challenges of immunogenicity and low drug entrapment efficiency. Herein, we summarize the advances in the engineering of LMWHs for controlled and prolonged delivery of chemotherapeutics for cancer, infectious diseases, and inflammatory disorders.

Implantable HDAC-inhibiting chemotherapeutics derived from hydrophobic amino acids for localized anticancer therapy

Epigenetic targeting of different cancers by inhibiting particular histone deacetylase (HDAC) isozymes is a promising treatment approach against cancer. Development of locally-implantable molecular inhibitors of HDAC (henceforth called HDACi) promises high tumour site concentration and reduced systemic degradation of the HDACi. Herein, we report the design of such implantable HDACi based on amphiphilic derivatives of hydrophobic amino acids endowed with a hydroxamic acid (hxa)-based zinc-binding residue. The amino acids present in HDACi influenced the HDAC isozyme that could be inhibited most effectively; the l-phenylalanine derivative 4e inhibited the HDAC6 isozyme most potently (IC50 ∼ 88 nM), while the l-isoleucine derivative 4h was most effective against the isozyme HDAC2 (IC50 ∼ 94 nM). We also noticed that the l-Phe derivative 4e was up to 5× more potent towards inhibiting HDAC6 than its optical antipode 4f derived from d-Phe. This was rationalized in terms of the varying extent of penetration of the enantiomeric inhibitors inside the catalytic tunnel of the enzyme. Since the isozymes HDAC6 and HDAC2 are overexpressed in different cancer cells, 4e and 4h elicited selective anticancer activity in different cancer cell lines. Additive therapeutic action of the combination therapy of 4e and 4h was observed on lung cancer cells that overexpress both these isozymes. Further, 4e formed implantable self-assembled hydrogels that achieved sustained and selective killing of cancer cells in the vicinity of implantation.

Electrospun Nanofibers for Cancer Therapy

Lately, a remarkable progress has been recorded in the field of electrospinning for the preparation of numerous types of nanofiber scaffolds. These scaffolds present some remarkable features including high loading capacity and encapsulation efficiency, superficial area and porosity, potential for modification, structure for the co-delivery of various therapies, and cost-effectiveness. Their present and future applications for cancer diagnosis and treatment are promising and pioneering. In this chapter we provide a comprehensive overview of electrospun nanofibers (ESNFs) applications in cancer diagnosis and treatment, covering diverse types of drug-loaded electrospun nanofibers.

Development of macroscopically ordered liquid crystalline hydrogels from biopolymers with robust antibacterial activity for controlled drug delivery applications

Macroscopically ordered liquid crystalline hydrogel with antibacterial activity for controlled drug delivery applications.

Advances in self-assembled injectable hydrogels for cancer therapy

Non-specific toxicity of chemotherapeutics and evolution of malignant tumors against them are major challenges for existing cancer chemotherapeutic regimens. Engineering of nanomaterials has attempted to minimize the toxicity of anticancer drugs, but systemic delivery of these nanomaterials still imposes many hurdles in their clinical use like burst release of chemotherapeutics and toxicity and immunogenicity associated with excipients of nanomaterials. However, there has been a surge in the development of natural and synthetic nanomaterials to deliver anticancer agents to the diseased (tumor) site as it can minimize the systemic circulation of anticancer drugs and reduce the toxicity-related challenges. Therefore, localized drug delivery is considered as the most effective way to deliver therapeutics but is further challenged by poor biodegradability, high immunogenicity, poor drug entrapment efficacy and inability to maintain sustained release of anticancer agents at the tumor site. This review maps out recent advancements in engineering of low molecular weight hydrogels derived from amino acid, fatty acyl, steroidal lipid and drug conjugated amphiphilic scaffolds. We have summarized the efforts for the development of molecular hydrogels in terms of biocompatibility, therapeutic potential and challenges associated with existing molecular hydrogels for cancer therapy.

Hydrogel-mediated delivery of celastrol and doxorubicin induces a synergistic effect on tumor regression via upregulation of ceramides

The release of anticancer drugs in systemic circulation and their associated toxicity are responsible for the poor efficacy of chemotherapy. Therefore, the identification of new chemotherapeutic combinations designed to be released near the tumor site in a sustained manner has the potential to enhance the efficacy and reduce the toxicity associated with chemotherapy. Here, we present the identification of a combination of doxorubicin, a DNA-binding topoisomerase inhibitor, with a naturally occurring triterpenoid, celastrol, that induces a synergistic effect on the apoptosis of colon cancer cells. Hydrogel-mediated sustained release of a combination of doxorubicin and celastrol in a murine tumor model abrogates tumor proliferation, and increases the median survival with enhanced apoptosis and concurrent reduction in proliferation. Sphingolipid profiling (LC-MS/MS) of treated tumors showed that the combination of celastrol and doxorubicin induces global changes in the expression of sphingolipids with an increase in levels of ceramides. We further demonstrate that this dual drug combination induces a significant increase in the expression of ceramide synthase 1, 4, and 6, thereby increasing the level of ceramides that contribute to the synergistic apoptotic effect. Therefore, hydrogel-mediated localized delivery of a combination of celastrol and doxorubicin provides a new therapeutic combination that induces a sphingolipid-mediated synergistic effect against colon cancer.

Amphiphilic phenylalanine derivatives that temporally generate reactive oxygen species from water in the presence of Au(iii) ions

Amphiphilic derivatives of phenylalanine (ADFs) have strong self-assembling propensities and yield low molecular weight hydrogels on multiple occassions. The interaction of ADFs with metal ions can result in the morphological changes in the self-assemblies. Herein, we report the interesting consequences of the interaction between four N-protected ADFs with Au(iii) ions. In the case of ADF 1, the original nanofibrillar morphology of the self-assemblies spontaneously transformed into uniform nanoglobules of ∼80 nm in diameter upon addition of Au(iii) ions. A subsequent reduction of the Au(iii) ions to Au(0) nanoparticles (AuNPs) and the surface decoration of the nanoglobules with AuNPs were observed in the course of the next six to eight hours. Simultaneously, multiple reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂), hydroxyl radicals (˙OH), singlet oxygen and superoxide ions were also found to be present in the reaction medium. These ROS originate from water used as the reaction medium. The ROS production and the reduction of Au(iii) were inhibited upon deaeration of the reaction medium and the use of heavy water (D₂O) or organic solvents as the reaction medium, while an increase in the pH of the aqueous medium intensified both these processes. We exploited the temporal ROS generation using the mixture of 1 and Au(iii) ions towards anticancer therapy by enhancing the intracellular ROS levels. It is expected that this effort can be expanded into a viable anticancer therapy in the near future by modulating the amount and the rate of ROS-generation through judicious choice of the peptidic ligands and metal ions.

Impact of atorvastatin loaded exosome as an anti-glioblastoma carrier to induce apoptosis of U87 cancer cells in 3D culture model

Exosomes (EXOs) are naturally occurring nanosized lipid bilayers that can be efficiently used as a drug delivery system to carry small pharmaceutical, biological molecules and pass major biological barriers such as the blood-brain barrier. It was hypothesized that EXOs derived from human endometrial stem cells (hEnSCs-EXOs) can be utilized as a drug carrier to enhance tumor-targeting drugs, especially for those have low solubility and limited oral bioactivity. In this study, atorvastatin (Ato) loaded EXOs (AtoEXOs) was prepared and characterized for its physical and biological activities in tumor growth suppression of 3 D glioblastoma model. The AtoEXOs were obtained in different methods to maximize drug encapsulation efficacy. The characterization of AtoEXOs was performed for its size, stability, drug release, and in vitro anti-tumor efficacy evaluated comprising inhibition of proliferation, apoptosis induction of tumor cells. Expression of apoptotic genes by Real time PCR, Annexin V/PI, tunnel assay was studied after 72 h exposing U87 cells where encapsulated in matrigel in different concentrations of AtoEXOs (5, 10 μM). The results showed that the prepared AtoEXOs possessed diameter ranging from 30-150 nm, satisfying stability and sustainable Ato release rate. The AtoEXOs was up taken by U87 and generated significant apoptotic effects while this inhibited tumor growth of U87 cells. Altogether, produced AtoEXOs formulation due to its therapeutic efficacy has the potential to be an adaptable approach to treat glioblastoma brain tumors.

Supramolecular Tubustecan Hydrogel as Chemotherapeutic Carrier to Improve Tumor Penetration and Local Treatment Efficacy

Local chemotherapy is a clinically proven strategy in treating malignant brain tumors. Its benefits, however, are largely limited by the rapid release and clearance of therapeutic agents and the inability to penetrate through tumor tissues. We report here on a supramolecular tubustecan (TT) hydrogel as both a therapeutic and drug carrier that enables long-term, sustained drug release and improved tumor tissue penetration. Covalent linkage of a tissue penetrating cyclic peptide to two camptothecin drug units creates a TT prodrug amphiphile that can associate into tubular supramolecular polymers and subsequently form a well-defined sphere-shaped hydrogel after injection into tumor tissues. The hollow nature of the resultant tubular assemblies allows for encapsulation of doxorubicin or curcumin for combination therapy. Our in vitro and in vivo studies reveal that these dual drug-bearing supramolecular hydrogels enhance tumor retention and penetration, serving as a local therapeutic depot for potent tumor regression, inhibition of tumor metastasis and recurrence, and mitigation of the off-target side effects.

Development of tilapia collagen and chitosan composite hydrogels for nanobody delivery

Recently, injectable hydrogels have shown great potential in cell therapy and drug delivery. They can easily fill in any irregular-shaped defects and remain in desired positions after implantation using minimally invasive strategies. Here, we developed hydrogels prepared from tilapia skin collagen and chitosan (HCC). The residual mass rate of HCC was affected by the pH at the time of preparation, which was 29.1 % at pH 7 in 36 h. By comparison, the residual mass ratios of HCC at pH values of 6 and 5 were only approximately 8.4 % and 0, respectively. In addition, the stability of HCC was also affected by the concentration of these two components. HCC10 catalyzed by 10 mg mL^-1 tilapia skin collagen and 10 mg mL^-1 chitosan was more stable than HCC5 catalyzed by 5 mg mL^-1 tilapia skin collagen and 10 mg mL^-1 chitosan; therefore, we studied that ability of HCC10 to deliver two model nanobodies: 2D5 and KPU. As the concentration of nanobodies increased, the cumulative release rate of 2D5 decreased, and the release rate of KPU increased. Meanwhile, the cumulative release rate of 2D5 was the highest (68.3 %) at pH 5.5, followed by pH 6.8 (56.4 %) and 7.4 (28.4 %). However, the cumulative release rates of KPU were similar at pH 5.5 (45.1 %), 6.8 (46.5 %), and 7.4 (44.9 %). HCC is biodegradable, and can facilitate the release nanobodies; thus, HCC could be developed into an intelligent responsive tumor treatment matrix for use in cancer therapy.

Orai3: Oncochannel with therapeutic potential

Ion channels in particular Calcium (Ca²⁺) channels play a critical role in physiology by regulating plethora of cellular processes ranging from cell proliferation, differentiation, transcriptional regulation and programmed cell death. One such physiologically important and highly Ca²⁺ selective channel family is Orai channels consisting of three homologs Orai1, Orai2 and Orai3. Orai channels are responsible for Ca²⁺ influx across the plasma membrane in response to decrease in Endoplasmic Reticulum (ER) Ca²⁺ stores. STIM1/STIM2 proteins sense the reduction in ER Ca²⁺ levels and activate Orai channels for restoring ER Ca²⁺ as well as for driving cellular functions. This signaling cascade is known as Store Operated Ca²⁺ Entry (SOCE). Although Orai1 is the ubiquitous SOCE channel protein, Orai2 and Orai3 mediate SOCE in certain specific tissues. Further, mammalian specific homolog Orai3 forms heteromultimeric channel with Orai1 for constituting Arachidonic acid regulated Ca²⁺ (ARC) channels or arachidonic acid metabolite Leukotriene C₄ (LTC₄) regulated Ca²⁺ (LRC) channels. Literature suggests that Orai3 regulates Breast, Prostate, Lung and Gastrointestinal cancers by either forming Store Operated Ca²⁺ (SOC) or ARC/LRC channels in the cancerous cells but not in healthy tissue. In this review, we would discuss the role of Orai3 in these cancers and would highlight the potential of therapeutic targeting of Orai3 for better management and treatment of cancer. Finally, we will deliberate on key outstanding questions in the field that demand critical attention and further studies.

Ultrashort Peptide Self-Assembly: Front-Runners to Transport Drug and Gene Cargos

The translational therapies to promote interaction between cell and signal come with stringent eligibility criteria. The chemically defined, hierarchically organized, and simpler yet blessed with robust intermolecular association, the peptides, are privileged to make the cut-off for sensing the cell-signal for biologics delivery and tissue engineering. The signature service and insoluble network formation of the peptide self-assemblies as hydrogels have drawn a spell of research activity among the scientists all around the globe in the past decades. The therapeutic peptide market players are anticipating promising growth opportunities due to the ample technological advancements in this field. The presence of the other organic moieties, enzyme substrates and well-established protecting groups like Fmoc and Boc etc., bring the best of both worlds. Since the large sequences of peptides severely limit the purification and their isolation, this article reviews the account of last 5 years' efforts on novel approaches for formulation and development of single molecule amino acids, ultra-short peptide self-assemblies (di- and tri- peptides only) and their derivatives as drug/gene carriers and tissue-engineering systems.

A Localized Chimeric Hydrogel Therapy Combats Tumor Progression through Alteration of Sphingolipid Metabolism

Rapid proliferation of cancer cells assisted by endothelial cell-mediated angiogenesis and acquired inflammation at the tumor microenvironment (TME) lowers the success rate of chemotherapeutic regimens. Therefore, targeting these processes using localized delivery of a minimally toxic drug combination may be a promising strategy. Here, we present engineering of a biocompatible self-assembled lithocholic acid-dipeptide derived hydrogel (TRI-Gel) that can maintain sustained delivery of antiproliferating doxorubicin, antiangiogenic combretastatin-A4 and anti-inflammatory dexamethasone. Application of TRI-Gel therapy to a murine tumor model promotes enhanced apoptosis with a concurrent reduction in angiogenesis and inflammation, leading to effective abrogation of tumor proliferation and increased median survival with reduced drug resistance. In-depth RNA-sequencing analysis showed that TRI-Gel therapy induced transcriptome-wide alternative splicing of many genes responsible for oncogenic transformation including sphingolipid genes. We demonstrate that TRI-Gel therapy targets the reversal of a unique intron retention event in β-glucocerebrosidase 1 (Gba1), thereby increasing the availability of functional Gba1 protein. An enhanced Gba1 activity elevates ceramide levels responsible for apoptosis and decreases glucosylceramides to overcome drug resistance. Therefore, TRI-Gel therapy provides a unique system that affects the TME via post-transcriptional modulations of sphingolipid metabolic genes, thereby opening a new and rational approach to cancer therapy.

Injectable Hydrogels for Cancer Therapy over the Last Decade

The interest in injectable hydrogels for cancer treatment has been significantly growing over the last decade, due to the availability of a wide range of starting polymer structures with tailored features and high chemical versatility. Many research groups are working on the development of highly engineered injectable delivery vehicle systems suitable for combined chemo-and radio-therapy, as well as thermal and photo-thermal ablation, with the aim of finding out effective solutions to overcome the current obstacles of conventional therapeutic protocols. Within this work, we have reviewed and discussed the most recent injectable hydrogel systems, focusing on the structure and properties of the starting polymers, which are mainly classified into natural or synthetic sources. Moreover, mapping the research landscape of the fabrication strategies, the main outcome of each system is discussed in light of possible clinical applications.

A novel low molecular weight nanocomposite hydrogel formulation for intra-tumoural delivery of anti-cancer drugs

Herein, an injectable formulation composed of a low molecular weight gelator (LMWG) based hydrogel and drug-loaded polymeric nanocapsules (NCs) is described. The NCs, made of hyaluronic acid and polyglutamic acid and loaded with C14-Gemcitabine (GEM C14), showed a size of 40 and 80 nm and a encapsulation efficiency >90%. These NCs exhibited a capacity to control the release of the encapsulated drug for >1 month. GEM C14-loaded NCs showed activity against various cancer cell lines in vitro; cell growth inhibition by 50% (GI₅₀) values of 15 ± 6, 10 ± 9, 13 ± 3 and 410 ± 463 nM were obtained in HCT 116, MIA PaCa-2, Panc-1 and Panc-1 GEM resistant cell lines respectively. Nanocomposite hydrogels were prepared using the LMWG - N4-octanoyl-2'-deoxycytidine and loaded for the first time with polymeric NCs. 2% and 4% w/v nanocapsule concentrations as compared to 8% w/v NC concentrations with 2% and 3% w/v gelator concentrations gave mechanically stronger gels as determined by oscillatory rheology. Most importantly, the nanocomposite formulation reformed instantly into a gel after injection through a needle. Based on these properties, the nanocomposite gel formulation has potential for the intratumoural delivery of anticancer drugs.

Nanocarrier-based systems for targeted and site specific therapeutic delivery

Systemic drug delivery methods such as oral or parenteral administration of free drugs possess relatively low treatment efficiency and marked adverse side effects. The use of nanoparticles for drug delivery in most cases substantially enhances drug efficacy, improves pharmacokinetics and drug release and limits their side effects. However, further enhancement in drug efficacy and significant limitation of adverse side effects can be achieved by specific targeting of nanocarrier-based delivery systems especially in combination with local administration. The present review describes major advantages and limitations of organic and inorganic nanocarriers or living cell-based drug and nucleic acid delivery systems. Among these, different nanoparticles, supramolecular gels, therapeutic cells as living drug carriers etc. have emerged as a new frontier in modern medicine.

Design of gel structures in water and oil phases for improved delivery of bioactive food ingredients

Gels are viscoelastic systems built up with a liquid phase entrapped in a three-dimensional network, which can behave as carriers for bioactive food ingredients. Many attempts have been made to design gel structures in the water phase (hydrogels, emulsion gels, bigels) or oil phase (organogels, bigels) in order to improve their delivery performances. Hydrogels are originated from proteins or polysaccharides, which are suitable for the delivery of hydrophilic ingredients. Organogels are mainly built up with the self-assembling of gelator molecules in the oil phase, and they offer good carriers for lipophilic ingredients. Emulsion gels and bigels, containing both aqueous and oil domains, can provide accommodations for lipophilic and hydrophilic ingredients simultaneously. Gel structures (e.g. rheology, texture, water holding capacity, swelling ratio) can be modulated by choosing different gelators, modifying gelation techniques, and the involvement of other ingredients (e.g. oils, emulsifiers, minerals, acids), which then alter the diffusion and release of the bioactive ingredients incorporated. Various studies have proved that gel-based delivery systems are able to improve the stability and bioavailability of many bioactive food ingredients. This review provides a state-to-art overview of different gel-based delivery systems, highlighting the significance of structure-functionality relationship, to provide advanced knowledge for the design of novel functional foods.

Instant hydrogel formation of terpyridine-based complexes triggered by DNA via non-covalent interaction

Biomolecule-based hydrogels have potential use in a wide range of applications such as controlled drug release, tissue engineering, and biofabrication. Herein, driven by specific interactions between ds-DNA (double-stranded DNA) and Zn2+ based metal-complexes, we report that the use of DNA as cross-linkers can enhance interactions between self-assembling Zn2+ complexes containing terpyridine and sugar groups in the generation of bioinspired hydrogels from solutions or suspensions. The gelation process is fast and straightforward without tedious steps and happens at room temperature. Such a hydrogelation process of different Zn2+ complexes endows the visualized and selective DNA analogue discrimination. Several experiments suggest that the strong intercalation binding of Zn2+ complexes with ds-DNA results in the unzipping of ds-DNA into ss-DNA (single-stranded DNA), which further behave as linkers to enhance the intermolecular interactions of self-assembling Zn2+ complex molecules via coordination interactions. This work demonstrates an efficient and universal strategy to prepare hydrogels based on biomolecular recognition. Moreover, the DNA responsive behaviors of Zn2+ complexes are further compared with that of solutions and cells.

Injectable Hydrogel of Vitamin B9 for the Controlled Release of Both Hydrophilic and Hydrophobic Anticancer Drugs

Folic acid (FA), vitamin B₉ , is a good receptor of drugs triggering cellular uptake via endocytosis. FA is sparingly soluble in water. Herein, a new approach for the formation of FA hydrogel by the hydrolysis of glucono-δ-lactone in PBS buffer under physiological conditions has been reported. The gel has a fibrillar network morphology attributable to intermolecular H-bonding and π-stacking interactions. The thixotropic property of the gel is used for the encapsulation of both hydrophilic [doxorubicin (DOX)] and hydrophobic [camptothecin (CPT)] drugs. The loading of DOX and CPT into the gel is attributed to the H-bonding interaction between FA and drugs. The release of DOX is sustainable at pH 4 and 7, and the Peppas model indicates that at pH 7 the diffusion of the drug is Fickian but it is non-Fickian at pH 4. The release of CPT is monitored by fluorescence spectroscopy, which also corroborates the combined release of both drugs. The metylthiazolyldiphenyltetrazolium bromide assay of FA hydrogel demonstrates nontoxic behavior and that the cytotoxicity of the DOX-loaded FA hydrogel is higher than that of pure DOX, with a minimal effect on normal cells.

The π-π stacking-guided supramolecular self-assembly of nanomedicine for effective delivery of antineoplastic therapies

In traditional nano drug-delivery systems, the complex chemical bonds between drug and carrier often complicate the preparation process and are less prone to rupture upon entry into the target, which is detrimental to the timely release of the drug. The π-π stacking provides us with a promising alternative as it is a weak interaction between the aromatic rings. Since most antitumor drugs are hydrophobic molecules with complex aromatic π-π-conjugated structures, the construction of self-assembly based on π-π stacking between drugs and carriers has the advantage of improving the stability and drug loading capacity as well as the improvement of hydrophilicity and biosafety. This article introduces the recent advances in π-π stacking-guided nano self-assembly for antineoplastic delivery.

In Situ Drug Delivery to Breast Cancer-Associated Extracellular Matrix

The extracellular matrix (ECM) contributes to tumor progression through changes induced by tumor and stromal cell signals that promote increased ECM density and stiffness. The increase in ECM stiffness is known to promote tumor cell invasion into surrounding tissues and metastasis. In addition, this scar-like ECM creates a protective barrier around the tumor that reduces the effectiveness of innate and synthetic antitumor agents. Herein, clinically approved breast cancer therapies as well as novel experimental approaches that target the ECM are discussed, including in situ hydrogel drug delivery systems, an emerging technology the delivers toxic chemotherapeutics, gene-silencing microRNAs, and tumor suppressing immune cells directly inside the tumor. Intratumor delivery of therapeutic agents has the potential to drastically reduce systemic side effects experienced by the patient and increase the efficacy of these agents. This review also describes the opposing effects of ECM degradation on tumor progression, where some studies report improved drug delivery and delayed cancer progression and others report enhanced metastasis and decreased patient survival. Given the recent increase in ECM-targeting drugs entering preclinical and clinical trials, understanding and addressing the factors that impact the effect of the ECM on tumor progression is imperative for the sake of patient safety and survival outcome.

Intra-articular injection of kartogenin-conjugated polyurethane nanoparticles attenuates the progression of osteoarthritis

Osteoarthritis (OA) is the most common form of joint disease and a leading cause of physical disability, there is an urgent need to attenuate the progression of OA. Intra-articular (IA) injection is an effective treatment for joints diseases, however, the therapeutic effects mostly depend on the efficacy of drug duration in joints. Drug delivery system can provide drug-controlled release and reduce the number of IA injection. In this study, amphiphilic polyurethanes with pendant amino group were synthesized and amide bonds were formed between the amine group of polyurethane and the carboxyl group of kartogenin (KGN), a small molecular reported to show both regenerative and protective effects on cartilage. Our results showed that KGN-conjugated polyurethane nanoparticles (PN-KGN) were spherical and regular in shape with an average size of 25 nm and could sustained and controlled release of KGN in vitro. PN-KGN showed no cytotoxicity and pro-inflammatory effects on chondrocytes. The therapeutic effects in OA model showed that IA injection of KGN could attenuate the progress of OA, however, the cartilage degeneration became obviously at 12 weeks with matrix loss and vertical fissures. By contrast, IA injection of PN-KGN showed less cartilage degeneration with significant lower OARSI scores even at 12 weeks, indicating PN-KGN could further arrest the development of OA. Immunohistochemistry also validated that IA injection of PN-KGN retained the normal compositions of cartilage matrix, with much stronger Col II staining and less Col I staining. In conclusion, IA injection of PN-KGN is a better potential strategy to treat OA, with long-time cartilage protection and less IA injections.

Injectable magnetic supramolecular hydrogel with magnetocaloric liquid-conformal property prevents post-operative recurrence in a breast cancer model

Locoregional recurrence of breast cancer after tumor resection represents several clinical challenges. Here, we demonstrate that co-delivery of chemotherapy and thermotherapeutic agents by a magnetic supramolecular hydrogel (MSH) following tumor resection prevents tumor recurrence in a breast cancer mouse model. The self-assembled MSH was designed through the partial inclusion complexation associated with the threading of α-CD on the copolymer moieties on the surface of the PEGylated iron oxide (Fe₃O₄) nanoparticles, which enables shear-thinning injection and controllable thermoreversible gel-sol transition. MSH was injected to the postoperative wound uniformly, which became mobile and perfect match with irregular cavity without blind angle due to the magnetocaloric gel-sol transition when exposed to alternating current magnetic field (ACMF). The magnetic nanoparticle-mediated induction heat during the gel-sol transition process caused the triggered release of dual-encapsulated chemotherapeutic drugs and provided an effect of thermally induced cell damage. The hierarchical structure of the MSH ensured that both hydrophobic and hydrophilic drugs can be loaded and consecutively delivered with different release curves. The hydrogel nanocomposite might provide a potential locally therapeutic approach for the precise treatment of locoregional recurrence of cancer.

STATEMENT OF SIGNIFICANCE

Tumor recurrence after resection represents several clinical challenges. In this study, we prepared shear-thinning injectable magnetic supramolecular hydrogel (MSH) and demonstrated their therapeutic applications in preventing the post-operative recurrence of breast cancer with facile synthesis and minimally invasive implantation in vivo. MSH was injected to the postoperative wound uniformly, which become mobile and perfect match with irregular cavity without blind angle through magnetocaloric gel-sol transition when exposed to ACMF. The magnetic nanoparticles mediated induction heat during the gel-sol transition process caused the triggered release of dual-encapsulated chemotherapeutic drugs as well as thermally induced cell damage. This study demonstrates that MSH with the controlled administration of combined thermo-chemotherapy exhibit great superiority in terms of preventing post-operation cancer relapse.

Multifunctional Electrospun Nanofibers for Enhancing Localized Cancer Treatment

Localized cancer treatment is one of the most effective strategies in clinical destruction of solid tumors at early stages as it can minimize the side effects of cancer therapeutics. Electrospun nanofibers have been demonstrated as a promising implantable platform in localized cancer treatment, enabling the on-site delivery of therapeutic components and minimizing side effects to normal tissues. This Review discusses the recent cutting-edge research with regard to electrospun nanofibers used for various therapeutic approaches, including gene therapy, chemotherapy, photodynamic therapy, thermal therapy, and combination therapy, in enhancing localized cancer treatment. Furthermore, it extensively analyzes the current challenges and potential breakthroughs in utilizing this novel platform for clinical transition in localized cancer treatment.

A multifunctional supramolecular hydrogel: preparation, properties and molecular assembly

A novel supramolecular hydrogel was designed and constructed by molecular self-assembly of a cationic gemini surfactant, 1,3-bis(N,N-dimethyl-N-cetylammonium)-2-propylacrylate dibromide (AGC₁₆), and an anionic aromatic compound, trisodium 1,3,6-naphthalenetrisulfonate (NTS). Owing to its unique structure, the hydrogel (abbreviated as AGC₁₆/NTS) has the potential to be used as a multifunctional drug delivery system. The structure and properties of AGC₁₆/NTS were characterized by rheological measurements, differential scanning calorimetry, variable-temperature ¹H nuclear magnetic resonance, ultraviolet-visible spectroscopy, variable-temperature fluorescence emission spectroscopy, cryogenic scanning electron microscopy, transmission electron microscopy and X-ray diffraction methods. The rheological and DSC analysis results revealed that the gel AGC₁₆/NTS was formed below 57 °C. It was found from UV-vis, fluorescence and ¹H NMR spectroscopy characterization that aromatic π-π stacking and hydrophobic forces were indispensable to the formation of AGC₁₆/NTS. The Cryo-SEM and TEM observation results indicated that gelators AGC₁₆ and NTS self-assembled into one-dimensional fibers which further tightly intertwined to form a three-dimensional network structure. Based on the spectroscopic data and X-ray diffraction measurement results, a self-assembly model was proposed, helping to further understand the molecular self-assembly mechanism of AGC₁₆/NTS. It was also found that the electrostatic force, hydrophobic force and π-π interaction were the three main driving forces for the gelation. The multiple non-covalent interactions between AGC₁₆ and NTS endowed the hydrogel with excellent performance when the hydrogel was used as a carrier for drug delivery, due to multiple micro-domains within the same gel system. We further investigated the encapsulation and releasing properties of the hydrogel, using the hydrophobic model drug curcumin (Cur) and the model drug naproxen sodium (Npx) with aromatic ring structure. The fluorescence spectroscopy analysis confirmed that Npx was carried through aromatic π-π stacking and the ¹H NMR measurement result revealed that Cur was encapsulated within the hydrophobic cavities of AGC₁₆/NTS through hydrophobic interaction. Moreover, the drug release study results showed a sustained release of drugs from the hydrogel, indicating good application prospects in exploring new multifunctional drug delivery systems.

Release of small bioactive molecules from physical gels

Pharmaceutical drugs with low water solubility have always received great attention within the scientific community. The reduced bioavailability and the need of frequent administrations have motivated the investigation of new drug delivery systems. Within this context, drug carriers that release their payload in a sustained way and hence reduce the administration rate are highly demanded. One interesting strategy to meet these requirements is the entrapment of the drugs into gels. So far, the most investigated materials for such drug-loaded gels are derived from polymers and based on covalent linkages. However, over the last decade the use of physical (or supramolecular) gels derived from low molecular weight compounds has experienced strong growth in this field, mainly due to important properties such as injectability, stimuli responsiveness and ease of synthesis. This review summarizes the use of supramolecular gels for the encapsulation and controlled release of small therapeutic molecules.

Fluorescent supramolecular hydrogels self-assembled from tetraphenylethene (TPE)/single amino acid conjugates

TPE-Ser molecules exhibit non-covalent interactions necessary for hydrogelation under physiological pH conditions.

A Substrate-Selective Enzyme-Catalysis Assembly Strategy for Oligopeptide Hydrogel-Assisted Combinatorial Protein Delivery

Oligopeptide hydrogels for localized protein delivery have considerable potential to reduce systemic side effects but maximize therapeutic efficacy. Although enzyme catalysis to induce formation of oligopeptide hydrogels has the merits of unique regio- and enantioselectivity and mild reaction conditions, it may cause the impairment of function and activity of the encapsulated proteins by proteolytic degradation during gelation. Here we report a novel enzyme-catalysis strategy for self-assembly of oligopeptide hydrogels using an engineered protease nanocapsule with tunable substrate selectivity. The protease-encapsulated nanocapsule shielded the degradation activity of protease on the laden proteins due to the steric hindrance by the polymeric shell weaved around the protease, whereas the small-molecular precursors were easier to penetrate across the polymeric network and access the catalytic pocket of the protease to convert to the gelators for self-assembling hydrogel. The resulting oligopeptide hydrogels supported a favorable loading capacity without inactivation of both an antiangiogenic protein, hirudin and an apoptosis-inducing cytokine, TRAIL as model proteins. The hirudin and TRAIL coloaded oligopeptide hydrogel for combination cancer treatment showed enhanced synergistic antitumor effects both in vitro and in vivo.

High encapsulation and localized delivery of curcumin from an injectable hydrogel

Most chemotherapy currently available for cancer treatment has limited potential to successful clinical cancer therapy, mainly due to low encapsulating capacity of drugs and unavailable pharmacologically beneficial concentrations at the tumor site. Herein, a novel yet simple strategy is developed to enhance drug encapsulating capacity and localized drug concentration using an injectable hydrogel based on thiolated chitosan (TCS) and poly(ethylene glycol) diacrylate (PEGDA). Almost 100% of encapsulating capacity is achieved when anti-cancer drug curcumin is encapsulated in the system. The interaction of curcumin with PEGDA is determined by fluorescence spectroscopy and the binding constant is calculated, followed by a simulation by a docking study using AutoDock. To improve the anti-tumor activity and achieve effective local concentrations, lysozyme is introduced into the system. Sustained curcumin release in a controlled lysozyme-responsive behaviour is observed, which enables the drug concentration to reach the therapeutic threshold promptly. The system displays efficient intracellular curcumin release to promote cancer cells apoptosis in vitro. In addition, the system effectively delays the tumor growth and reduces adverse effects in tumor-bearing nude mice. The strategy of localized, high encapsulation of drug by using an injectable hydrogel would be particularly beneficial with many insoluble anti-cancer drugs.