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Chitosan has been widely used in biomedical fields due to its good antibacterial properties, excellent biocompatibility, and biodegradability. In this study, a pH-responsive and self-healing hydrogel was synthesized from 3-carboxyphenylboronic acid grafted with chitosan (CS-BA) and polyvinyl alcohol (PVA). The dynamic boronic ester bonds and intermolecular hydrogen bonds are responsible for the hydrogel formation. By changing the mass ratio of CS-BA and PVA, the tensile stress and compressive stress of hydrogel can controlled in the range of 0.61 kPa - 0.74 kPa and 295.28 kPa - 1108.1 kPa, respectively. After doping with tannic acid (TA)/iron nanocomplex (TAFe), the hydrogel successful killed tumor cells through the near infrared laser-induced photothermal conversion and the TAFe-triggered reactive oxygen species generation. Moreover, the photothermal conversion of the hydrogel and the antibacterial effect of CS and TA give the hydrogel a good antibacterial effect. The CS-BA/PVA/TAFe hydrogel exhibit good in vivo and in vitro anti-tumor recurrence and antibacterial ability, and therefore has the potential to be used as a powerful tool for the prevention of local tumor recurrence and bacterial infection after surgery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Helicobacter pylori (H. pylori) is one of the major causes of gastrointestinal diseases, including gastric cancer. However, the acidic environment of the stomach and H. pylori resistance severely impair the antimicrobial efficacy of oral drugs. Here, a biocompatible chitosan-modified molybdenum selenide (MoSe 2 @CS) was designed for the simultaneous photothermal treatment of H. pylori infection and gastric cancer. MoSe 2 @CS showed a photothermal conversion efficiency was as high as 45.7 %. In the H. pylori-infected mice model, MoSe 2 @CS displayed a high bacteriostasis ratio of 99.9 % upon near-infrared irradiation. The antimicrobial functionality was also proved by transcriptomic sequencing study, which showed that MoSe 2 @CS combined with NIR laser irradiation modulated the gene expression of a variety of H. pylori bioprocesses, including cell proliferation and inflammation-related pathways. Further gut flora analysis results indicated that MoSe 2 @CS mediated PTT of H. pylori did not affect the homeostasis of gut flora, which highlights its advantages over traditional antibiotic therapy. In addition, MoSe 2 @CS exhibited a good photothermal ablation effect and significantly inhibited gastric tumor growth in vitro and in vivo. The comprehensive application of MoSe 2 @CS in the PTT of H. pylori infection and gastric cancer provides a new avenue for the clinical treatment of H. pylori infection and related diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In emergencies, uncontrolled severe bleeding can result in undesired complications and even death of the injured. Designing advanced hemostatic agents is a potential solution for emergency hemostasis, yet it remains challenging to realize the persistent adhesion in a wet wound environment. In this study, based on dynamic reversible Schiff base bond and photo-initiated double-bond polymerization, a novel injectable hemostatic hydrogel (L-COC) consisting of methacrylated carboxymethyl chitosan (CMCSMA), oxidized konjac glucomannan (OKGM) and (+)-catechin hydrate (CH) was synthesized for emergency hemostasis. To our delight, the incorporated CH imparted enhanced blood procoagulantion to the L-COC hydrogel by intensifying the hydrogel-red blood cell interactions. As a result, the hemostatic effect of the engineered L-COC hydrogel was significantly superior to that of fluid gelatin Surgiflo TM for liver bleeding wounds in rats (Blood loss: 0.62 ± 0.11 g (L-COC), 0.90 ± 0.08 g (Surgiflo TM ); hemostasis time: 69.0 ± 2.9 s (L-COC), 84.0 ± 2.2 s (Surgiflo TM )). With the favorable antioxidant and antibacterial activities, as well as multifunctional properties, the bio-adhesive L-COC hydrogel and the underlying design principles may facilitate further development of practical hemostatic hydrogels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Excess free radicals at the wound site can cause an inflammatory response, which is not conducive to wound healing. Hydrogels with antioxidant properties can prevent inflammatory storms by scavenging free radicals from the wound site and inhibiting the release of inflammatory factors. In this study, we prepared the carboxymethyl chitosan (CMCS)/polyvinyl pyrrolidone (PVP)/Molybdenum (IV) Selenide (MoSe 2 ), and platelet-rich plasma (PRP) (CMCS/PVP/MoSe 2 /PRP) hydrogels for accelerating the repair of wounds. In the hydrogels, the MoSe 2 can scavenge various free radicals to reduce oxidative stress at the site of inflammation, endowed the hydrogels with antioxidant properties. Interestingly, growth factors released by PRP assisted the tissue repair by promoting the formation of new capillaries. CMCS as a backbone not only showed good biocompatibility and biodegradability but also played a significant role in maintaining the sustained release of growth factors. In addition, incorporating PVP enhanced the tissue adhesion and mechanical properties. The multifunctional composite antioxidant hydrogels have good swelling properties and biodegradability, which is completely degraded within 28 days. Thus, the antioxidant CMCS/PVP/MoSe 2 /PRP hydrogels provide a new idea for designing ideal multifunctional wound dressings., (© 2024. The Author(s).)

The rapid development of functional materials and manufacturing technologies is fostering advances in piezoelectric materials (PEMs). PEMs can convert mechanical energy into electrical energy. Unlike traditional power sources, which need to be replaced and are inconvenient to carry, PEMs have extensive potential applications in smart wearable and implantable devices. However, the application of conventional PEMs is limited by their poor flexibility, low ductility, and susceptibility to fatigue failure. Incorporating hydrogels, which are flexible, stretchable, and self-healing, providing a way to overcome these limitations of PEMs. Hydrogel-based piezoelectric materials (H-PEMs) not only resolve the shortcomings of traditional PEMs but also provide biocompatibility and more promising application potential. This paper summarizes the working principle of H-PEMs. Recent advances in the use of H-PEMs as sensors and in vitro energy harvesting devices for smart wearable devices are described in detail, with emphasis on application scenarios in human body like fingers, wrists, ankles, and feet. In addition, the recent progress of H-PEMs in implantable medical devices, especially the potential applications in human body parts such as bones, skin, and heart, are also elaborated. In addition, challenges and potential improvements in H-PEMs are discussed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogels have been widely used as wound dressings to accelerate wound healing. However, due to the impaired skin barrier at the wound site, external bacteria can easily invade the wound and cause infection. In this study, we designed a dopamine-modified sodium alginate/carboxymethyl chitosan/polyvinylpyrrolidone (CPD) hydrogel, which was able to promote wound healing while preventing wound infection. Due to the high content of catechol groups, the CPD hydrogel exhibited good tissue adhesion ability and a significant scavenging ability for DPPH• and PTIO• radicals. Under near-infrared laser irradiation, the temperature of CPD hydrogel increased significantly, which significantly killed the Staphylococcus aureus and Escherichia coli. The cell migration test confirmed that CPD hydrogel could promote the cell migration ratio. In the in vivo wound healing test for infected full-thickness skin defect, CPD hydrogel significantly inhibited bacterial proliferation and enhanced wound healing rate. Therefore, the multifunctional hydrogel is expected to be applied to wound healing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Benefiting from the biocompatibility, adhesiveness, and natural extracellular matrix-mimicking ability, hydrogels have received increasing research in recent years. In this study, a hydrogel system composed of dopamine, quaternized ammoniated chitosan (QCS), and polyvinylpyrrolidone was reported to exhibit fast hemostatic properties in Sprague-Dawley rat tail amputation and liver bleeding models. The results showed that this hydrogel had good hemostatic properties. The designed hydrogel showed high swelling ratios in H 2 O, PBS, and 0.9 % NaCl solution, indicating its capability to absorb tissue residual exudate and form a stable hydrogel. Compared with the control group, the blood loss in Sprague-Dawley rat tail amputation and liver bleeding were reduced by nearly 78 % and 76 %, respectively. Interestingly, dopamine endowed the hydrogel with antioxidant properties, thus holding a great application promise in inflammatory wounds. Furthermore, the designed hydrogel demonstrated good and reversible adhesion properties (12.23 ± 0.22 kPa-24.31 ± 0.55 kPa), ensuring its firm attachment to bleeding wounds of pig skin in wet environments. This research points out a novel path for designing chitosan-based hydrogels for biomedical applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The rapid and effective hemostasis of gastrointestinal bleeding sites remains an urgent clinical challenge. In this study, an ultrafast self-gelling, sprayable, and adhesive carboxymethyl chitosan/poly-γ-glutamic acid/oxidized dextran (CPO) powder was designed for gastric perforation hemostasis and healing. When the CPO powder was sprayed to the gastric perforation site, the CPO powder absorbed water from the blood and concentrate blood cells and clotting factors to achieve the purpose of rapid hemostasis. During the hemostasis, the CPO powder formed a hydrogel in situ through the formation of amide bonds and Schiff base bonds within 15 s, forming a physical barrier to cover the wound surface. Concurrently, the aldehyde group (-CHO) of oxidized dextran formed additional Schiff base bonds with the amino group (-NH 2 ) of the tissue, enabling the CPO powder with wound surface adhesion. Moreover, the CPO powder was shown to have excellent in vitro and in vivo antibacterial properties and it was able to promote the healing of infected wounds in a mouse model. In summary, CPO powder provides a promising idea for the rational design of gastrointestinal hemostatic agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Hydrogel with a 3D network structure can cover the wound to stop the bleeding and support the host tissue infiltration and integration. In this study, an antibacterial hydrogel with hemostasis and the ability to promote wound healing is proposed. This hydrogel comprised surfactin, polyvinylpyrrolidone, and methacrylic anhydride (MA) grafted quaternary ammonium chitosan (CS-MA). The hydrogel formation is triggered by the ultraviolet-initiated polymerization of CS-MA, while the surfactin is complexed with the hydrogel through hydrogen bonding interaction. The results showed that this hydrogel is an adhesive hydrogel with shape adaptability, which can cover the wound surface and promote contact between the hydrogel and the wound surface. More importantly, this hydrogel can simulate the microenvironment of the primary extracellular matrix and increase collagen deposition, and inflammatory factor transformation. The designing of such a multi-functional hydrogel is expected to provide a novel approach to promoting the healing of wounds., (© 2023 Wiley-VCH GmbH.)

Stopping bleeding at an early stage and promoting wound healing are of great significance for efficient wound management. In this study, a carboxymethyl chitosan (CMCS)/poly-γ-glutamic acid (γ-PGA)/platelet-rich plasma (PRP) hydrogel (CP-PRP hydrogel) was firstly prepared by crosslinking of CMCS with γ-PGA and the enzymatic coagulation of PRP. Then, the CP-PRP hydrogel was freeze-dried and transformed into a sponge (CP-PRP sponge). A series of safety experiments with cells, blood, and tissues proved the biocompatibility of the CP-PRP sponge. Importantly, the CP-PRP sponge was able to adhere and condense red blood cells, which accelerated blood clotting. Therefore, the CP-PRP sponge showed an enhanced hemostasis effect compared to SURGIFLO® Hemostatic Matrix. Moreover, in vitro and in vivo experiments showed that the sponge was able to release epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF). Thus, in a mouse model of full-thickness skin defects, the wounds of the sponge-treated mice were significantly healed within two weeks. These results proved the transforming potential of the CP-PRP sponge as a novel bioactive wound dressing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The conventional method of using montmorillonite hemostatic materials affects the hemostatic effect due to easy dislodgement on the wound surface. In this paper, a multifunctional bio-hemostatic hydrogel (CODM) was prepared based on hydrogen bonding and Schiff base bonding using modified alginate, polyvinylpyrrolidone (PVP), and carboxymethyl chitosan. The amino group-modified montmorillonite was uniformly dispersed in the hydrogel by its amido bond formation with the carboxyl groups of carboxymethyl chitosan and oxidized alginate. The catechol group, -CHO, and PVP can form hydrogen bonds with the tissue surface to afford the firm tissue adhesion to afford the wound hemostatic. The addition of montmorillonite-NH 2 further improves the hemostatic ability, making it better than commercial hemostatic materials. Moreover, the photothermal conversion ability (derived from the polydopamine) was synergized with the phenolic hydroxyl group, quinone group, and the protonated amino group to effectively kill the bacteria in vitro and in vivo. Based on its in vitro and in vivo biosafety and satisfactory degradation ratio anti-inflammatory, antibacterial, and hemostatic properties, the CODM hydrogel holds promising potential for emergency hemostasis and intelligent wound management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this study, a composite hydrogel (QMPD hydrogel) composed of methacrylate anhydride (MA) grafted quaternary ammonium chitosan (QCS-MA), polyvinylpyrrolidone (PVP), and dopamine (DA) was designed for the sequential wound inflammation elimination, infection inhibition, and wound healing. The QMPD hydrogel formation was initiated by the ultraviolet light-triggered polymerization of QCS-MA. Furthermore, hydrogen bonds, electrostatic interactions, and "π-π" stacking between QCS-MA, PVP, and DA were involved in the hydrogel formation. In this hydrogel, the quaternary ammonium groups of quaternary ammonium chitosan and the photothermal conversion of polydopamine are capable of killing bacteria on wounds, which showed the bacteriostatic ratios of 85.6 % and 92.5 % toward Escherichia coli and Staphylococcus aureus, respectively. Moreover, the oxidation of DA sufficiently scavenged free radicals and introduced the QMPD hydrogel with good anti-oxidant and anti-inflammatory abilities. Together with the extracellular matrix-mimic tropical structure, the QMPD hydrogel significantly promoted the wound management of mice. Therefore, the QMPD hydrogel is expected to provide a new method for the design of wound healing dressings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The postoperative recurrence has adversely affected the treatment of tumors. Besides, the potential bacterial infection at the wound site may lead to a series of tissue necrosis. Here, we developed an injectable γ-polyglutamic acid/carboxymethyl chitosan/polydopamine hydrogel (PCP) for simultaneously reducing the postoperative infection and preventing the tumor recurrence. On the one hand, the aqueous solution of carboxymethyl chitosan oxidized the dopamine into polydopamine; on the other, the carboxymethyl chitosan was cross-linked with the activated γ-polyglutamic acid to form a hydrogel. After local implantation, the PCP hydrogel effectively killed tumor cells and bacteria under 808 nm laser irradiation. In addition, carboxymethyl chitosan rendered the hydrogel with anti-bacterial properties as well as anti-tumor efficiencies. The anti-tumor recurrence and anti-bacterial efficiencies of PCP hydrogel were proved on a tumor-removed mouse model and a Staphylococcus aureus-infected mouse model, respectively. Moreover, the hydrogel has the advantages of good biocompatibility and simple preparation, and thus has potential application prospects in the prevention of tumor recurrence and wound bacterial infection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Hydrogel is a kind of hemostatic agent with good application prospect. However, the water molecules on the wound made the hydrogel less adhesive to wet wound tissue. Herein, the carboxymethyl chitosan (CMCS)/oxidized dextran (OD)/γ-polyglutamic acid (γ-PGA) hydrogel was prepared using a double-barreled syringe for hemostasis of diffuse and incompressible wound bleeding. The hydrogel formation was based on the intramolecular lactam bonds, intermolecular amide bonds, and Schiff base bonds. In the hydrogel, the super hydrophilic γ-PGA could drain the surface moisture of the wound and create a local dry environment for enhanced surface adhesion. In vivo study showed that the CMCS/ODex/γ-PGA hydrogel possesses a good biosafety and biodegradability. Interestingly, the CMCS/ODex/γ-PGA hydrogel exhibited excellent hemostatic abilities in dynamic humid environment and resisted a high blood pressure of 238 mmHg, which exceeds the threshold systolic blood pressure of healthy adults (i.e., 120 mmHg). Together with the antibacterial and reactive nitrogen species scavenging activities, this study is expected to provide a new method to design the wet-surface adhesives for the efficient hemostatic application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The design of new hemostatic materials to mitigate uncontrolled bleeding in emergencies is challenging. Chitosan-based hemostatic hydrogels have frequently been used for hemostasis due to their unique biocompatibility, tunable mechanical properties, injectability, and ease of handling. Moreover, chitosan (CS) absorbs red blood cells and activates platelets to promote hemostasis. Benefiting from these desired properties, the hemostatic application of CS hydrogels is attracting ever-increasing research attention. This paper reviews the recent research progress of CS-based hemostatic hydrogels and their advantageous characteristics compared to traditional hemostatic materials. The effects of the hemostatic mechanism, effects of deacetylation degree, relative molecular mass, and chemical modification on the hemostatic performance of CS hydrogels are summarized. Meanwhile, some typical applications of CS hydrogels are introduced to provide references for the preparation of efficient hemostatic hydrogels. Finally, the future perspectives of CS-based hemostatic hydrogels are presented.

Hydrogel is a three-dimensional network polymer material rich in water. It is widely used in the biomedical field because of its unique physical and chemical properties and good biocompatibility. In recent years, the incidence of inflammatory bowel disease (IBD) has gradually increased, and the disadvantages caused by traditional drug treatment of IBD have emerged. Therefore, there is an urgent need for new treatments to alleviate IBD. Hydrogel has become a potential therapeutic platform. However, there is a lack of comprehensive review of functional hydrogels for IBD treatment. This paper first summarizes the pathological changes in IBD sites. Then, the action mechanisms of hydrogels prepared from chitosan, sodium alginate, hyaluronic acid, functionalized polyethylene glycol, cellulose, pectin, and γ-polyglutamic acid on IBD were described from aspects of drug delivery, peptide and protein delivery, biologic therapies, loading probiotics, etc. In addition, the advanced functions of IBD treatment hydrogels were summarized, with emphasis on adhesion, synergistic therapy, pH sensitivity, particle size, and temperature sensitivity. Finally, the future development direction of IBD treatment hydrogels has been prospected., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Currently, hydrogels are widely studied for wound dressings. However, wound healing is often hindered by bacterial infection. In this study, in situ cross-linked carboxymethyl chitosan (CMCS)/oxidized dextran (OD)/poly-γ-glutamic acid (γ-PGA) (COP) hydrogel was prepared for antimicrobial and hemostasis of diffuse wounds. In the COP hydrogel, γ-PGA was able to drain the surface moisture of the wound to enhance the surface adhesion. Moreover, γ-PGA could concentrate blood by absorbing plasma, and CMCS could electrostatically adsorb negative RBCs. The antibacterial properties of CMCS and OD endowed the COP hydrogel with certain antibacterial effects. In the inhibition zone experiment, an obvious inhibition zone appeared around the COP hydrogel. In vivo studies showed that the COP hydrogel significantly inhibited bacterial growth and promoted wound healing. In the rat tail diffuse hemorrhage wound model, the COP hydrogel showed superior hemostasis ability. Therefore, the multifunctional COP hydrogel is expected to find different applications in wound hemostasis and healing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Massive bleeding is a great threat to the life safety of patients, which is a challenging clinical problem. Therefore, it is urgent to develop a kind of multifunctional dressing material with hemostatic ability and antibacterial performance to promote wound healing and repair. To resolve this issue, in this study, a carboxymethyl chitosan (CMCS)/sodium alginate (SA)/oxidized dextran (ODE) (CSO) multifunctional hydrogel was developed. The hydrogel could rapidly gel through Schiff base reaction and amide reaction and firmly adhere to the skin at the wound, to realize the fast hemostasis. Importantly, it was verified that the hydrogel could prevent the Staphylococcus aureus-caused wound infection, owing to the antibacterial effect of CMCS and ODE. In addition, the CSO hydrogel had good water retention capacity and was able to mimic the three-dimensional structure of the natural extracellular matrix, thereby promoting wound repair in mice. In vitro whole-blood clotting assay demonstrated that red blood cells could be adhered to the surface of hydrogel, showing good hemostasis in rat liver injury and tail amputation models. Together with the biocompatible feature, CSO hydrogel holds a great application prospect in hemostasis and wound healing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In recent years, multifunctional hydrogels have received a great deal of attention because they are biocompatible and can mimic the extracellular matrix. Herein, we prepared hydrogels of biocompatible cross-linked networks with photothermal properties. In this study, a chitosan/polyaniline/laponite (COL) hydrogel with photothermal conversion capability was designed. Polyaniline was firstly grafted onto chitosan and its solution was mixed with oxidized dextran, which was then cross-linked into a hydrogel via a Schiff base reaction. Furthermore, an aluminosilicate clay material, laponite (LAP), was incorporated into the hydrogel. The swelling ratio of the COL hydrogel in various solutions was greater than 580%, and it showed good degradation ability (the mass-loss ratio was over 45% after 28 days). This composite hydrogel was demonstrated to have good photothermal conversion properties and biocompatibility at both the cell (cell viability was over 97%) and animal levels. The COL hydrogel showed a photothermal conversion efficiency of 23.7% under the irradiation of a near-infrared laser. Coupled with the osteogenic differentiation-inducing potential of LAP, the COL hydrogel has the potential to kill tumors via hyperthermia or serve as scaffolds for bone tissue regeneration.

Hierarchical nanoparticles are of great interest because they possess unique physicochemical properties and multiple functionalities, providing a wealth of possibilities for various applications. In this work, we have developed a well-designed method to prepare hierarchical magnetic nanoparticles Fe₃O₄@mSiO₂@CS by integrating a solvothermal method for synthesizing the Fe₃O₄ core, a dualtemplating micelle system for preparing a layer of mesoporous silica (mSiO₂) shell, and a silane coupling method via γ -glycidoxypropyltrimethoxysilane for binding a chitosan (CS) layer on the silica surface. The porous hierarchical nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering nanoparticle size analyzer, and specific surface area and pore size analyzer. The loading capacity and the release behavior of the as-prepared nanoparticles for doxorubicin hydrochloride were studied, and it was found that the drug release rate was faster at pH 6.0 than at pH 7.4, revealing the pH-responsive property of the nanoparticles.

The purpose of this study was to design an injectable hydrogel with temperature-sensitive property for safe and high efficient in vivo colon cancer hyperthermia and chemotherapy. Chitosan (CS) solution was injected into the tumor at room temperature and automatically gelled after warming to body temperature in the present of β-glycerophosphate (β-GP). Combined localized tumor photothermal and chemotherapy were achieved by dissolving photothermal material MoS 2 /Bi 2 S 3 -PEG (MBP) nanosheets and drug molecule doxorubicin (DOX) into the hydrogel, and the gel system could encapsulate DOX and MBP nanosheets and prevent them from entering the blood circulation and damaging normal tissues and cells. More importantly, the CS/MBP/DOX (CMD) hydrogel exhibited a photothermal efficiency of 22.18% and 31.42% in the first and second near infrared light (NIR I and NIR II) biowindows respectively at a low MBP concentration (0.5 mg/mL). Besides, the release of the DOX from CMD hydrogel was controllable since the gel temperature could be governed by NIR laser irradiation. Moreover, the chitosan-based hydrogel had antibacterial effects. The designed composite hydrogel is anticipated to act as a platform for the high efficient treatment of tumors owing to the different penetration depths of NIR I and NIR II., (Copyright © 2019 Elsevier Ltd. All rights reserved.)