Laponite nanodisks as an efficient platform for Doxorubicin delivery to cancer cells

Hydrogel-exosome system in tissue engineering: A promising therapeutic strategy

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

Natural alkaloids from Dicranostigma leptopodum (Maxim.) Fedde and their G5. NHAc-PBA dendrimer-alkaloid complexes for targeting chemotherapy in breast cancer MCF-7 cells

Herein, we isolated five natural alkaloids, iso-corydine (iso-CORY), corydine (CORY), sanguinarine (SAN), chelerythrine (CHE) and magnoflorine (MAG), from traditional medicinal herb Dicranostigma leptopodum (Maxim.) Fedde (whole herb) and elucidated their structures. Then we synthesised G5. NHAc-PBA as targeting dendrimer platform to encapsulate the alkaloids into G5. NHAc-PBA-alkaloid complexes, which demonstrated alkaloid-dependent positive zeta potential and hydrodynamic particle size. G5. NHAc-PBA-alkaloid complexes demonstrated obvious breast cancer MCF-7 cell targeting effect. Among the G5. NHAc-PBA-alkaloid complexes, G5.NHAc-PBA-CHE (IC50=13.66 μM) demonstrated the highest MCF-7 cell inhibition capability and G5.NHAc-PBA-MAG (IC50=24.63 μM) had equivalent inhibitory effects on cell proliferation that comparable to the level of free MAG (IC50=23.74 μM), which made them the potential breast cancer targeting formulation for chemotherapeutic application. This work successfully demonstrated a pharmaceutical research model of 'natural bioactive product isolation-drug formulation preparation-breast cancer cell targeting inhibition'.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Laponite for biomedical applications: An ophthalmological perspective

Clay minerals have been applied in biomedicine for thousands of years. Laponite is a nanostructured synthetic clay with the capacity to retain and progressively release drugs. In recent years there has been a resurgence of interest in Laponite application in various biomedical areas. This is the first paper to review the potential biomedical applications of Laponite in ophthalmology. The introduction briefly covers the physical, chemical, rheological, and biocompatibility features of different routes of administration. After that, emphasis is placed on 1) drug delivery for antibiotics, anti-inflammatories, growth factors, other proteins, and cancer treatment; 2) bleeding prevention or treatment; and 3) tissue engineering through regenerative medicine using scaffolds in intraocular and extraocular tissue. Although most scientific research is not performed on the eye, both the findings and the new treatments resulting from that research are potentially applicable in ophthalmology since many of the drugs used are the same, the tissue evaluated in vitro or in vivo is also present in the eye, and the pathologies treated also occur in the eye. Finally, future prospects for this emerging field are discussed.

Structure, rheological properties, and biocompatibility of Laponite® cross-linked starch/polyvinyl alcohol hydrogels

Hydrogels, owing to their unique porous structures, hydrophilic properties, and biocompatibility, are being developed as scaffolds for bone grafts. However, the use of toxic initiators or cross-linking agents is a drawback. To overcome this, we developed Laponite®/cross-linked starch/polyvinyl alcohol (PVA) hydrogels prepared by one-step solution mixing. The structure, rheological properties, and biocompatibility of the hydrogels were investigated. Zeta potential, Fourier transform infrared, and X-ray diffraction analyses showed that hydrogen bonding and electrostatic interactions jointly maintained the structure of the cross-linked hydrogel systems. At a Laponite® concentration of 10 %, the hydrogel with a starch/PVA ratio of 2:2 exhibited a uniform porous structure, the highest storage modulus (G'), and the lowest degradation rate. At a starch/PVA ratio of 2:2, the G' increased; however, the degradation rate decreased with the increase in Laponite® content from 5 % to 20 %. These results indicate that the mechanical strength and degradation rate of the hydrogels could be adjusted by altering the starch/PVA ratio and the amount of Laponite®. In vitro cytotoxicity experiments showed that the Laponite®/starch/PVA (LSP) hydrogels were non-toxic to MC3T3-E1 cells. The starch/PVA ratio had no obvious effect on the proliferation of MC3T3-E1 cells, but an increase in Laponite® content significantly promoted cell proliferation. In summary, the results suggest that these LSP hydrogels have great potential for applications in bone tissue engineering.

Tracking cellular uptake, intracellular trafficking and fate of nanoclay particles in human bone marrow stromal cells

Clay nanoparticles, in particular synthetic smectites, have generated interest in the field of tissue engineering and regenerative medicine due to their utility as cross-linkers for polymers in biomaterial design and as protein release modifiers for growth factor delivery. In addition, recent studies have suggested a direct influence on the osteogenic differentiation of responsive stem and progenitor cell populations. Relatively little is known however about the mechanisms underlying nanoclay bioactivity and in particular the cellular processes involved in nanoclay-stem cell interactions. In this study we employed confocal microscopy, inductively coupled plasma mass spectrometry and transmission electron microscopy to track the interactions between clay nanoparticles and human bone marrow stromal cells (hBMSCs). In particular we studied nanoparticle cellular uptake mechanisms and uptake kinetics, intracellular trafficking pathways and the fate of endocytosed nanoclay. We found that nanoclay particles present on the cell surface as μm-sized aggregates, enter hBMSCs through clathrin-mediated endocytosis, and their uptake kinetics follow a linear increase with time during the first week of nanoclay addition. The endocytosed particles were observed within the endosomal/lysosomal compartments and we found evidence for both intracellular degradation of nanoclay and exocytosis as well as an increase in autophagosomal activity. Inhibitor studies indicated that endocytosis was required for nanoclay upregulation of alkaline phosphatase activity but a similar dependency was not observed for autophagy. This study into the nature of nanoclay-stem cell interactions, in particular the intracellular processing of nanosilicate, may provide insights into the mechanisms underlying nanoclay bioactivity and inform the successful utilisation of clay nanoparticles in biomaterial design.

A Drug-Eluting Injectable NanoGel for Localized Delivery of Anticancer Drugs to Solid Tumors

Systemically administered chemotherapy reduces the efficiency of the anticancer agent at the target tumor tissue and results in distributed drug to non-target organs, inducing negative side effects commonly associated with chemotherapy and necessitating repeated administration. Injectable hydrogels present themselves as a potential platform for non-invasive local delivery vehicles that can serve as a slow-releasing drug depot that fills tumor vasculature, tissue, or resection cavities. Herein, we have systematically formulated and tested an injectable shear-thinning hydrogel (STH) with a highly manipulable release profile for delivering doxorubicin, a common chemotherapeutic. By detailed characterization of the STH physical properties and degradation and release dynamics, we selected top candidates for testing in cancer models of increasing biomimicry. Two-dimensional cell culture, tumor-on-a-chip, and small animal models were used to demonstrate the high anticancer potential and reduced systemic toxicity of the STH that exhibits long-term (up to 80 days) doxorubicin release profiles for treatment of breast cancer and glioblastoma. The drug-loaded STH injected into tumor tissue was shown to increase overall survival in breast tumor- and glioblastoma-bearing animal models by 50% for 22 days and 25% for 52 days, respectively, showing high potential for localized, less frequent treatment of oncologic disease with reduced dosage requirements.

Delicate Hybrid Laponite-Cyclic Poly(ethylene glycol) Nanoparticles as a Potential Drug Delivery System

The objective of the study was to explore the feasibility of a new drug delivery system using laponite (LAP) and cyclic poly(ethylene glycol) (cPEG). Variously shaped and flexible hybrid nanocrystals were made by both the covalent and physical attachment of chemically homogeneous cyclized PEG to laponite nanodisc plates. The size of the resulting, nearly spherical particles ranged from 1 to 1.5 µm, while PEGylation with linear methoxy poly (ethylene glycol) (mPEG) resulted in fragile sheets of different shapes and sizes. When infused with 10% doxorubicin (DOX), a drug commonly used in the treatment of various cancers, the LAP-cPEG/DOX formulation was transparent and maintained liquid-like homogeneity without delamination, and the drug loading efficiency of the LAP-cPEG nano system was found to be higher than that of the laponite-poly(ethylene glycol) LAP-mPEG system. Furthermore, the LAP-cPEG/DOX formulation showed relative stability in phosphate-buffered saline (PBS) with only 15% of the drug released. However, in the presence of human plasma, about 90% of the drug was released continuously over a period of 24 h for the LAP-cPEG/DOX, while the LAP-mPEG/DOX formulation released 90% of DOX in a 6 h burst. The results of the cell viability assay indicated that the LAP-cPEG/DOX formulation could effectively inhibit the proliferation of A549 lung carcinoma epithelial cells. With the DOX concentration in the range of 1-2 µM in the LAP-cPEG/DOX formulation, enhanced drug effects in both A549 lung carcinoma epithelial cells and primary lung epithelial cells were observed compared to LAP-mPEG/DOX. The unique properties and effects of cPEG nanoparticles provide a potentially better drug delivery system and generate interest for further targeting studies and applications.

Laponite-Based Nanocomposite Hydrogels for Drug Delivery Applications

Hydrogels are widely used for therapeutic delivery applications due to their biocompatibility, biodegradability, and ability to control release kinetics by tuning swelling and mechanical properties. However, their clinical utility is hampered by unfavorable pharmacokinetic properties, including high initial burst release and difficulty in achieving prolonged release, especially for small molecules (<500 Da). The incorporation of nanomaterials within hydrogels has emerged as viable option as a method to trap therapeutics within the hydrogel and sustain release kinetics. Specifically, two-dimensional nanosilicate particles offer a plethora of beneficial characteristics, including dually charged surfaces, degradability, and enhanced mechanical properties within hydrogels. The nanosilicate-hydrogel composite system offers benefits not obtainable by just one component, highlighting the need for detail characterization of these nanocomposite hydrogels. This review focuses on Laponite, a disc-shaped nanosilicate with diameter of 30 nm and thickness of 1 nm. The benefits of using Laponite within hydrogels are explored, as well as examples of Laponite-hydrogel composites currently being investigated for their ability to prolong the release of small molecules and macromolecules such as proteins. Future work will further characterize the interplay between nanosilicates, hydrogel polymer, and encapsulated therapeutics, and how each of these components affect release kinetics and mechanical properties.

Pentoxifylline/Chitosan Films on Wound Healing: In Vitro/In Vivo Evaluation

This study aimed to develop films of chitosan (CSF) associated with pentoxifylline (PTX) for healing cutaneous wounds. These films were prepared at two concentrations, F1 (2.0 mg/mL) and F2 (4.0 mg/mL), and the interactions between the materials, structural characteristics, in vitro release, and morphometric aspects of skin wounds in vivo were evaluated. The formation of the CSF film with acetic acid modifies the polymeric structure, and the PTX demonstrates interaction with the CSF, in a semi-crystalline structure, for all concentrations. The release for all films was proportional to the concentration, with two phases: a fast one of ≤2 h and a slow one of >2 h, releasing 82.72 and 88.46% of the drug after 72 h, being governed by the Fickian diffusion mechanism. The wounds of the mice demonstrate a reduction of up to 60% in the area on day 2 for F2 when compared to CSF, F1, and positive control, and this characteristic of faster healing speed for F2 continues until the ninth day with wound reduction of 85%, 82%, and 90% for CSF, F1, and F2, respectively. Therefore, the combination of CSF and PTX is effective in their formation and incorporation, demonstrating that a higher concentration of PTX accelerates skin-wound reduction.

Enhanced delivery of quercetin and doxorubicin using β-cyclodextrin polymer to overcome P-glycoprotein mediated multidrug resistance

In this study, we prepared a β-cyclodextrin polymer (β-CDP) co-loaded quercetin (QCT) and doxorubicin (DOX) nanocarrier (β-CDP/QD NCs) by freeze-dried method to combat P-glycoprotein (P-gp) mediated multidrug resistance (MDR) in KB-Ch^R 8-5 cancer cells. Various microscopic and spectroscopic techniques were employed to characterize the prepared nanocarrier. The molecular docking studies confirm the effective binding interactions of QCT and DOX with the synthesized β-CD polymer. The in vitro drug release study illustrates the sustainable release of DOX and QCT from the β-CDP nanocarrier. Further, we noticed that the QCT released from the β-CDP nanocarrier improved the intracellular availability of DOX via modulating P-gp drug efflux function in KB-Ch^R 8-5 cells and MCF-7/DOX cancer cells. Cell uptake results confirmed the successful internalization of DOX in KB-Ch^R 8-5 cells compared with free DOX. Cell-based assays such as nuclear condensation, alteration in the mitochondrial membrane potential (MMP), and apoptosis morphological changes confirmed the enhanced anticancer effect of β-CDP/QD NCs in the resistant cancer cells. Hence, QCT and DOX co-loaded β-CDP may be considered effective in achieving maximum cell death in the P-gp overexpressing MDR cancer cells.

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.

Engineering Bio-MOF/polydopamine as a biocompatible targeted theranostic system for synergistic multi-drug chemo-photothermal therapy

In this study, a biodegradable multifunctional photothermal drug delivery nanoparticles (MPH NPs) using curcumin (Cur) as the ligand coated with hyaluronic acid (HA) was successfully prepared, which could simultaneously deliver Cur and doxorubicin hydrochloride (DOX·HCl) to overcome the common drug resistance in cancer cells. Polydopamine (PDA) as a protective shell prevents premature degradation of Cur in physiological environment and enables it to play effective medicinal value. MPH NPs can specifically recognize CD44 receptors on the surface of cancer cells for tumor targeting, with the damage of the partially released DOX to the superficial tumor cells, and then the positively charged Cur released may gradually penetrate into the cells through electron interaction to improve the problem of low permeability. In vitro cell experiments showed that hydrophobic/hydrophilic drugs co-loaded MPDH (MPH loaded with DOX·HCl) could enter the cancer cells through the endocytosis mediated by clathrin / caveolin, and the inhibition rate of MPDH on HeLa cells reached 79.28 % irradiation under 808 nm laser. MPH were composed of safe materials that have been proven to be biodegradable in human body, which avoided the disadvantages that NPs were difficult to discharge and caused damage to normal organs during long-term use.

Study of oxygen-deficient W18O49-based drug delivery system readily absorbed through cellular internalization pathways in tumor-targeted chemo-/photothermal therapy

W₁₈O₄₉-mediated photothermal therapy (PTT) is affected by the easily oxidized property and its direct exposure to physiological environment can cause biological events, which limit its development in the biomedical field. Herein, a composite nanoparticle PVP-W₁₈O₄₉@C (PW@C), with significant antioxidant and excellent biocompatibility, was constructed to overcome the limitations of W₁₈O₄₉ in the medical field. Oxygen-deficient W₁₈O₄₉, with irregular defect structure, was combined with hollow carbon nanospheres treated by reflux to obtain W₁₈O₄₉@C (W@C) similar to sea urchins. Compared with W₁₈O₄₉, W@C shows stronger antioxidant properties, and it still has the ability to convert light energy to heat energy after 6 months. In addition, polyvinyl pyrrolidone is coated on the surface of W@C to construct PW@C, which significantly improves biocompatibility of W@C. The photothermal conversion efficiency of PW@C was 42.9 ± 1.3. PWD (PW@C loaded with DOX·HCl) showed controllable drug release behavior under pH and NIR stimulation, and the drug release rate reached 69.1 ± 1.6% at pH = 5.0. Notably, PWD was readily absorbed by cells through clathrin/caveolae-mediated internalization channels, and the viability of HeLa cells treated with PWD + NIR was only 21.5 ± 1.0%. Through photothermal, drug delivery/release and cytotoxicity evaluation, PWD was proved to be an effective platform for chemo-/photothermal combinational tumor therapy.

Laponite-Based Nanomaterials for Drug Delivery

Laponite is a clay-based material composed of synthetic disk-shaped crystalline nanoparticles with highly ionic, large surface area. These characteristics enable the intercalation and dissolution of biomolecules in Laponite-based drug delivery systems. Furthermore, Laponite's innate physicochemical properties and architecture enable the development of tunable pH-responsive drug delivery systems. Laponite's coagulation capacity and cation exchangeability determine its exchange capabilities, drug encapsulation efficiency, and release profile. These parameters are exploited to design highly controlled and efficacious drug delivery platforms for sustained drug release. In this review, they provide an overview of how to design efficient delivery of therapeutics by leveraging the properties and specific interactions of various Laponite-polymer composites and drug moieties.

Tranexamic acid-loaded hemostatic nanoclay microsphere frameworks

Fast acting topical hemostatic agents play a key role in hemorrhage control. Retarding fibrinolysis is also critical in improving coagulation, thereby expanding chances of survival. The purpose of the present work was to investigate the physical properties, loading capacity and hemostatic efficacy of newly developed nanoclay microsphere frameworks (NMFs) loaded with tranexamic acid (TA), as antifibrinolytic agent. Nanoclay compositions were prepared with increasing levels of TA. Results showed that TA was successfully incorporated into the nanoclay structure and released when solvated with ethanol. Both doped and undoped NMFs significantly decreased activated partial thromboplastin time and increased clot stiffness, which was attributed to significantly thinner fibrin fibers and a denser clot structure.

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

Injectable shear-thinning biomaterials (STBs) have attracted significant attention because of their efficient and localized delivery of cells as well as various molecules ranging from growth factors to drugs. Recently, electrostatic interaction-based STBs, including gelatin/LAPONITE® nanocomposites, have been developed through a simple assembly process and show outstanding shear-thinning properties and injectability. However, the ability of different compositions of gelatin and LAPONITE® to modulate doxorubicin (DOX) delivery at different pH values to enhance the effectiveness of topical skin cancer treatment is still unclear. Here, we fabricated injectable STBs using gelatin and LAPONITE® to investigate the influence of LAPONITE®/gelatin ratio on mechanical characteristics, capacity for DOX release in response to different pH values, and cytotoxicity toward malignant melanoma. The release profile analysis of various compositions of DOX-loaded STBs under different pH conditions revealed that lower amounts of LAPONITE® (6NC25) led to higher pH-responsiveness capable of achieving a localized, controlled, and sustained release of DOX in an acidic tumor microenvironment. Moreover, we showed that 6NC25 had a lower storage modulus and required lower injection forces compared to those with higher LAPONITE® ratios. Furthermore, DOX delivery analysis in vitro and in vivo demonstrated that DOX-loaded 6NC25 could efficiently target subcutaneous malignant tumors via DOX-induced cell death and growth restriction.

Adsorption and Sustained Delivery of Small Molecules from Nanosilicate Hydrogel Composites

Two-dimensional nanosilicate particles (NS) have shown promise for the prolonged release of small-molecule therapeutics while minimizing burst release. When incorporated in a hydrogel, the high surface area and charge of NS enable electrostatic adsorption and/or intercalation of therapeutics, providing a lever to localize and control release. However, little is known about the physio-chemical interplay between the hydrogel, NS, and encapsulated small molecules. Here, we fabricated polyethylene glycol (PEG)-NS hydrogels for the release of model small molecules such as acridine orange (AO). We then elucidated the effect of NS concentration, NS/AO incubation time, and the ability of NS to freely associate with AO on hydrogel properties and AO release profiles. Overall, NS incorporation increased the hydrogel stiffness and decreased swelling and mesh size. When individual NS particles were embedded within the hydrogel, a 70-fold decrease in AO release was observed compared to PEG-only hydrogels, due to adsorption of AO onto NS surfaces. When NS was pre-incubated and complexed with AO prior to hydrogel encapsulation, a >9000-fold decrease in AO release was observed due to intercalation of AO between NS layers. Similar results were observed for other small molecules. Our results show the potential for use of these nanocomposite hydrogels for the tunable, long-term release of small molecules.

An in vitro assessment of the toxicity of two-dimensional synthetic and natural layered silicates

Natural Layered Silicates (NLS) and Synthetic Layered Silicates (SLS) are a diverse group of clay minerals that have attracted great interest in various branches of industry. However, despite growing demand for this class of material, their impact on human health has not been fully investigated. Therefore, the aim of this study was to evaluate and compare the potential toxic effects of a wide range of commercially available SLS and NLS of varying physicochemical properties (lithium (Li) or fluoride (F) content and size). Mouse BALB/c monocyte macrophage (J774A.1) and human monocyte-derived macrophages (MDMs) were chosen as in vitro models of alveolar macrophages. Montmorillonite, hectorite, Medium (med) F/High Li and Low F/Med Li particles, were cytotoxic to cells and induced potent pro-inflammatory responses. The remaining particles (No F/Very (V)Low Li, No F/Med Li, No F/Low Li, High F/Med Li and High F/Med Li washed) were non- to relatively low- cytotoxic and inflammogenic, in both type of cells. In an acellular condition none of the tested samples increased reactive oxygen species (ROS), while ROS generation was observed following exposure to sublethal concentrations of Med F/High Li, Low F/Med Li, montmorillonite and hectorite samples, in J774A.1 cells. Based on the results obtained in this study the toxic potency of tested samples was not associated with lithium or fluoride content, but appeared to be dependent on particle size, with the platelets of larger dimension and lower surface area being more potent than the smaller platelet particles with higher surface area. In addition, the increased bioactivity of Med F/High Li and Low F/Med Li was associated with endotoxin contamination. Obtained results demonstrated that layered silicate materials have different toxicological profiles and suggest that toxicological properties of a specific layered silicate should be investigated on an individual basis.

Converging 2D Nanomaterials and 3D Bioprinting Technology: State-of-the-Art, Challenges, and Potential Outlook in Biomedical Applications

The development of next-generation of bioinks aims to fabricate anatomical size 3D scaffold with high printability and biocompatibility. Along with the progress in 3D bioprinting, 2D nanomaterials (2D NMs) prove to be emerging frontiers in the development of advanced materials owing to their extraordinary properties. Harnessing the properties of 2D NMs in 3D bioprinting technologies can revolutionize the development of bioinks by endowing new functionalities to the current bioinks. First the main contributions of 2D NMS in 3D bioprinting technologies are categorized here into six main classes: 1) reinforcement effect, 2) delivery of bioactive molecules, 3) improved electrical conductivity, 4) enhanced tissue formation, 5) photothermal effect, 6) and stronger antibacterial properties. Next, the recent advances in the use of each certain 2D NMs (1) graphene, 2) nanosilicate, 3) black phosphorus, 4) MXene, 5) transition metal dichalcogenides, 6) hexagonal boron nitride, and 7) metal-organic frameworks) in 3D bioprinting technology are critically summarized and evaluated thoroughly. Third, the role of physicochemical properties of 2D NMSs on their cytotoxicity is uncovered, with several representative examples of each studied 2D NMs. Finally, current challenges, opportunities, and outlook for the development of nanocomposite bioinks are discussed thoroughly.

Two-dimensional biomaterials: material science, biological effect and biomedical engineering applications

To date, nanotechnology has increasingly been identified as a promising and efficient means to address a number of challenges associated with public health. In the past decade, two-dimensional (2D) biomaterials, as a unique nanoplatform with planar topology, have attracted explosive interest in various fields such as biomedicine due to their unique morphology, physicochemical properties and biological effect. Motivated by the progress of graphene in biomedicine, dozens of types of ultrathin 2D biomaterials have found versatile bio-applications, including biosensing, biomedical imaging, delivery of therapeutic agents, cancer theranostics, tissue engineering, as well as others. The effective utilization of 2D biomaterials stems from the in-depth knowledge of structure-property-bioactivity-biosafety-application-performance relationships. A comprehensive summary of 2D biomaterials for biomedicine is still lacking. In this comprehensive review, we aim to concentrate on the state-of-the-art 2D biomaterials with a particular focus on their versatile biomedical applications. In particular, we discuss the design, fabrication and functionalization of 2D biomaterials used for diverse biomedical applications based on the up-to-date progress. Furthermore, the interactions between 2D biomaterials and biological systems on the spatial-temporal scale are highlighted, which will deepen the understanding of the underlying action mechanism of 2D biomaterials aiding their design with improved functionalities. Finally, taking the bench-to-bedside as a focus, we conclude this review by proposing the current crucial issues/challenges and presenting the future development directions to advance the clinical translation of these emerging 2D biomaterials.

Smart luminescent hydrogel with superior mechanical performance based on polymer networks embedded with lanthanide containing clay nanocomposites

Due to their inherent biocompatibility and unique optical properties, luminescent hydrogels have recently garnered tremendous interest. However, most of the explored luminescent hydrogels cannot well meet the requirements of both sufficient mechanical properties and smart luminescence. Here we report a smart luminescent hydrogel with superior mechanical performance by in situ copolymerization of the acrylamide monomers and lanthanide loaded clay nanosheets. The Eu-DPA@clay nanosheets emitting center can not only be well dispersed in aqueous solution, but also maintain robust luminescence. Interestingly, the additional interaction between the Eu-DPA@clay nanosheets and the polymer network endows the hydrogel with excellent mechanical properties. Moreover, a luminescence on/off switch is also achieved by alternative acid and base stimuli, which may have potential applications in smart luminescent devices.

Photosensitizing nanoclays for efficient cell uptake and in vitro photodynamic therapy

In this study a straightforward strategy to deliver photosensitizing molecules into cancer cells by using Laponite RD® (LAP) nanodisks as carrier is presented. We report the application of LAP functionalized with a highly hydrophobic Silicon phthalocyanine photosensitizer (SiPc) for efficient cell uptake and photodynamic therapy (PDT) of MCF-7 breast cancer cells in vitro. This inorganic-organic hybrid nanomaterial caused a threefold increase in intracellular ROS levels and 99.7% of cancer cell inactivation after light treatment (630 nm; fluency of 108 J/cm²). With its theranostic capabilities (simultaneous fluorescence and singlet oxygen generation), uptake into cancer cells was monitored to control the photo-inactivation. The functionalized nanodisks already proved to be an efficient photo-inactivator of pathogenic Gram-(+) bacteria and were previously reported as LS10. By extending the use of LS10 to PDT of cancer cells, it is an example of a photosensitizer functionalized nanoclay with multipurpose drug characteristics, demonstrating an intriguing potential for future phototherapeutic studies and applications.

Nanocomposite gels of poloxamine and Laponite for β-Lapachone release in anticancer therapy

Nano-hybrid systems have been shown to be an attractive platform for drug delivery. Laponite® RD (LAP), a biocompatible synthetic clay, has been exploited for its ability to establish of strong secondary interactions with guest compounds and hybridization with polymers or small molecules that improves, for instance, cell adhesion, proliferation, and differentiation or facilitates drug attachment to their surfaces through charge interaction. In this work, LAP was combined with Tetronics, X-shaped amphiphilic PPO-PEO (poly (propylene oxide)-poly (ethylene oxide) block copolymers. β-Lapachone (BLPC) was selected for its anticancer activity and its limited bioavailability due to very low aqueous solubility, with the aim to improve this by using LAP/Tetronic nano-hybrid systems. The nanocarriers were prepared over a range of Tetronic 1304 concentrations (1 to 20% w/w) and LAP (0 to 3% w/w). A combination of physicochemical methods was employed to characterize the hybrid systems, including rheology, particle size and shape (DLS, TEM), thermal analysis (TG and DSC), FTIR, solubility studies and drug release experiments. In vitro cytotoxicity assays were performed with BALB/3T3 and MCF-7 cell lines. In hybrid systems, a sol-gel transition can occur below physiological temperature. BLPC exhibits the most significant increase in solubility in formulations with a high concentration of T1304 (over 10% w/w) and 1.5% w/w LAP, or systems with only LAP (1.5%), with a 50 and 100-fold increase in solubilisation, respectively. TEM images showed spherical micelles of T1304, which elongated into wormlike micelles with concentration (20%) and in the presence of LAP, a finding that has not been reported before. A sustained release of BLPC over 140 hours was achieved in one of the formulations (10% T1304 with 1.5% laponite), which also showed the best selectivity index towards cancer cells (MCF-7) over BALB/3T3 cell lines. In conclusion, BLPC-loaded T1304/LAP nano-hybrid systems proved safe and highly effective and are thus a promising formulation for anticancer therapy.

Color-Tunable Aqueous Room-Temperature Phosphorescence Supramolecular Assembly

Developing room-temperature phosphorescence (RTP) materials with color-tunability performance in an aqueous environment is crucial for application in optoelectronic areas to a higher stage, such as multicolor display, visual detection of external stimulus, and high-level information anticounterfeiting, but still faces a formidable challenge. Herein, we propose an efficient design strategy to develop excitation wavelength-responsive RTP supramolecular co-assembly systems of a simple benzoic acid derivative and Laponite (Lap) clay nanoplates in aqueous solution, displaying an ultralong lifetime (0.632 s) and a high phosphorescence quantum efficiency (18.04%) simultaneously. Experimental and theoretical research studies suggest that this distinctive feature is due to the generation of more and efficient intersystem crossing pathways benefiting from the coexistence of isolated and J-aggregation states via controlling the doping of the benzoic acid derivative and the inhibition of phosphorescence quenching by water because of the synergistic effects of robust hydrogen-bonding interactions between Lap and the benzoic acid derivative, J-aggregations of the benzoic acid derivative, and good oxygen tolerance of the Lap clay. By virtue of their excellent RTP performances in aqueous solution, the visual colorimetric detection of Ag⁺ in a water environment was achieved for the first time, and visible and high-level information encryption was accomplished as well.

Recent advances in the design of inorganic and nano-clay particles for the treatment of brain disorders

Inorganic materials, in particular nanoclays and silica nanoparticles, have attracted enormous attention due to their versatile and tuneable properties, making them ideal candidates for a wide range of biomedical applications, such as drug delivery. This review aims at overviewing recent developments of inorganic nanoparticles (like porous or mesoporous silica particles) and different nano-clay materials (like montmorillonite, laponites or halloysite nanotubes) employed for overcoming the blood brain barrier (BBB) in the treatment and therapy of major brain diseases such as Alzheimer's, Parkinson's, glioma or amyotrophic lateral sclerosis. Recent strategies of crossing the BBB through invasive and not invasive administration routes by using different types of nanoparticles compared to nano-clays and inorganic particles are overviewed.

Steady and Oscillatory Shear Flow Behavior of Different Polysaccharides with Laponite®

The rheological behavior, in terms of steady and oscillatory shear flow, of Laponite^® with different polysaccharides (alginate, chitosan, xanthan gum and levan) in salt-free solutions was studied. Results showed that a higher polymer concentration increased the zero-rate viscosity and decreased the critical strain rate (Cross model fit) as well as increasing the elastic and viscous moduli. Those properties (zero-rate viscosity and critical strain rate) can be a suitable indicator of the effect of the Laponite^® on the shear flow behavior for the different solutions. Specifically, the effect of the Laponite^® predominates for solutions with large critical strain rate and low zero-rate viscosity, modifying significantly the previous parameters and even the yield stress (if existing). On the other hand, larger higher polymeric concentration hinders the formation of the platelet structure, and polymer entanglement becomes predominant. Furthermore, the addition of high concentrations of Laponite^® increases the elastic nature, but without modifying the typical mechanical spectra for polymeric solutions. Finally, Laponite^® was added to (previously crosslinked) gels of alginate and chitosan, obtaining different results depending on the material. These results highlight the possibility of predicting qualitatively the impact of the Laponite^® on different polymeric solutions depending on the solutions properties.

Cooperativity between Dimerization and Binding Equilibria in the Ternary System Laponite-Indocyanine Green-Water

Laponite is an artificial nanoclay available in large quantities and at low cost. This marterial represents an efficient and suitable way of delivering hydrophobic vital dyes without the need for chemical functionalization. Laponite is available in large quantities and at low cost, then it would be an efficient way of delivering hydrophobic vital dyes without the need for chemical functionalization. The hydrodynamic diameter of laponite extrapolated to infinite dilution indicates that this clay is completely exfoliated. Furthermore, the hydrodynamic diameter in the laponite-Indocyanine green-water ternary system, at a fixed laponite concentration (2% (m/m)) exhibits a saturation curve. It was found that the extrapolated diameter at dye zero concentration is smaller than in pure water. Absorption spectra with fixed concentration of dye exhibit a red shift of 10–13 nm. On the contrary, the spectra acquired at a constant concentration of laponite do not undergo any displacement. The deconvolution of the spectra with two Gaussian peaks allows to calculate the concentration of the monomeric and dimeric species. The results were interpreted as a synergy between the dye dimerization balance and the dye-laponite binding.

Functional LAPONITE Nanodisks Enable Targeted Anticancer Chemotherapy in Vivo

Development of nanoplatforms for targeted anticancer drug delivery for effective tumor therapy still remains challenging in the development of nanomedicine. Here, we present a facile method to formulate a LAPONITE (LAP) nanodisk-based nanosystem for anticancer drug doxorubicin (DOX) delivery to folic acid (FA) receptor-overexpressing tumors. In the current work, aminated LAP nanodisks were first prepared through silanization, then functionalized with polyethylene glycol-linked FA (PEG-FA) via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) chemistry, and finally employed to physically encapsulate DOX. The formed functional LAP nanodisks (for short, LM-PEG-FA) possess a high DOX loading efficiency (88.6 ± 1.2%) and present a pH-dependent release feature with a quicker DOX release under acidic pH conditions (pH 5.0) than under physiological pH conditions (pH 7.4). In vitro flow cytometry, confocal microscopic observation, and cell viability assay show that the LM-PEG-FA/DOX complexes can be specifically taken up by FAR-overexpressing human ovarian cancer cells (SK-OV-3 cells) and present a specific cancer cell therapeutic effect. Further tumor treatment results reveal that the LM-PEG-FA/DOX complexes can exert a specific therapeutic efficacy to a xenografted SK-OV-3 tumor model in vivo when compared with nontargeted LM-mPEG/DOX complexes. Therefore, the developed LM-PEG-FA nanodisks could be employed as a potential platform for targeted cancer chemotherapy.

Silicate bioceramics: from soft tissue regeneration to tumor therapy

Great efforts have been devoted to exploiting silicate bioceramics for various applications in soft tissue regeneration, owing to their excellent bioactivity. Based on the inherent ability of silicate bioceramics to repair tissue, bioactive ions are easily incorporated into silicate bioceramics to endow them with extra biological properties, such as enhanced angiogenesis, antibiosis, enhanced osteogenesis, and antitumor effect, which significantly expands the application of multifunctional silicate bioceramics. Furthermore, silicate nanobioceramics with unique structures have been widely employed for tumor therapy. In recent years, the novel applications of silicate bioceramics for both tissue regeneration and tumor therapy have substantially grown. Eliminating the skin tumors first and then repairing the skin wounds has been widely investigated by our groups, which might shed some light on treating other soft tissue tumor or tumor-induced defects. This review first describes the recent advances made in the development of silicate bioceramics as therapeutic platforms for soft tissue regeneration. We then highlight the major silicate nanobioceramics used for tumor therapy. Silicate bioceramics for both soft tissue regeneration and tumor therapy are further emphasized. Finally, challenges and future directions of silicate bioceramics stepping into the clinics are discussed. This review will inspire researchers to create the efficient and functional silicate bioceramics needed for regeneration and tumor therapy of other tissues.

Layered Silicate-Alginate Composite Particles for the pH-Mediated Release of Theophylline

Numerous natural and synthetic clay minerals have proven to be excellent drug carriers for high drug-loaded and sustained release formulations due to their considerable ion exchange, adsorption, and swelling capacities. Moreover, the synthetic smectite clays have added advantages in terms of compositional purity and controlled cation exchange capacity in comparison to natural clays. This study involves the intercalation of theophylline (TP) in a synthetic clay, Laponite^® (LP), followed by the inclusion of the resulting intercalates into sodium alginate (SA) beads to achieve pH-controlled drug release. Maximum intercalated drug incorporation of 68 mg/g was obtained by ion exchange at pH 1.2 and confirmed by an increase in basal spacing of the clay from 12.9 to 15.5 Å. TP release from the binary LP-TP intercalates in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) was found to be 40% and 70%, respectively. LP-TP particles were also incorporated in an SA matrix via polymer crosslinking using CaCl_2(aq) to improve the pH selective release. The ternary polymer-clay-drug composite particles effectively prevented the release of TP at low pH in SGF and resulted in sustained release in SIF, with 40% dissolution within 120 min.

Laponite/poly(2-methyl-2-oxazoline) hydrogels: Interplay between local structure and rheological behaviour

HYPOTHESIS

Dispersions of Laponite in water may form gels, the rheological properties of which being possibly tuned by the addition of polymer chains. Laponite-based hydrogels with poly(ethylene oxide) (PEO) were the most widely investigated systems and the PEO chains were then found to reduce the elastic modulus.

EXPERIMENTS

Here, hydrogels based on Laponite and poly(2-methyl-2-oxazoline) (POXA) were considered. The adsorption behavior and the local structures within these nanocomposite gels were investigated by small-angle neutron scattering and NMR. The same materials were macroscopically characterized using rheology.

FINDINGS

An original evolution of the storage modulus G' with the POXA concentration is evidenced compared to Laponite/PEO hydrogels. At low POXA concentrations, a continuous reduction of G' is observed upon increasing the polymer content, as with PEO, due to the screening of electrostatic interactions between the clay platelets. However, above a critical value of the POXA concentration, G' increases with the polymer content. This difference with PEO-based hydrogels is correlated to the stronger affinity of POXA chains for the clay surfaces, which results in the reduction of the inhomogeneities for the Laponite disks within the gels. Steric repulsions would then counterbalance the effect of electrostatic repulsions and lead to the strengthening of the POXA-based hydrogels.

Poly(ionic liquid)-Gated CuCo2S4 for pH-/Thermo-Triggered Drug Release and Photoacoustic Imaging

A novel hybrid drug nanocarrier is developed with CuCo₂S₄ nanoparticles as the core to be encapsulated by poly(ionic liquid) (PIL), that is, poly(tetrabutylphosphonium styrenesulfonate) (P[P_4,4,4,4][SS]), as the shell. Doxorubicin (DOX) is loaded onto the PIL shell via electrostatic attraction involving amine in DOX and styrenesulfonate in PIL. pH- and thermal-responsive characteristics of P[P_4,4,4,4][SS] endow the multifunctional hybrid nanocarrier system DOX-CuCo₂S₄@PIL with sensitive dual-stimuli-triggered drug release behaviors. The CuCo₂S₄ core converts near-infrared (NIR) irradiation into thermal energy to trigger the shrinkage of the PIL shell, which subsequently promotes drug release, and the pH-responsive release of DOX involves pH-sensitive electrostatic interaction of the PIL shell with DOX. A favorable controlled release of 90.5% is achieved under pH/thermo dual stimuli. In vitro experiments with MCF-7 cells well demonstrated that the drug release is controlled by the acidic intracellular environment with NIR irradiation. The CuCo₂S₄ core also serves as a photoacoustic (PA) imaging contrast agent, as demonstrated by in vivo treatment of the MCF-7-carrying mice.

Laponite-based Nanomaterials for Biomedical Applications: A Review

Laponite based nanomaterials (LBNMs) are highly diverse regarding their mechanical, chemical, and structural properties, coupled with shape, size, mass, biodegradability and biocompatibility. These ubiquitous properties of LBNMs make them appropriate materials for extensive applications. These have enormous potential for effective and targeted drug delivery comprised of numerous biodegradable materials which results in enhanced bioavailability. Moreover, the clay material has been explored in tissue engineering and bioimaging for the diagnosis and treatment of various diseases. The material has been profoundly explored for minimized toxicity of nanomedicines. The present review compiled relevant and informative data to focus on the interactions of laponite nanoparticles and application in drug delivery, tissue engineering, imaging, cell adhesion and proliferation, and in biosensors. Eventually, concise conclusions are drawn concerning biomedical applications and identification of new promising research directions.

A glance over doxorubicin based-nanotherapeutics: From proof-of-concept studies to solutions in the market

Cancer is one of the leading causes of death worldwide and, as such, efforts are being done to find new chemotherapeutic drugs or, alternatively, novel approaches for the delivery of old ones. In this scope, when used as vehicles for drugs, nanomaterials may potentially maximize the efficacy of the treatment and reduce its side effects, for example by a change in drug's pharmacokinetics, cell targeting and/or specific stimuli-responsiveness. This is the case of doxorubicin (DOX) that presents a broad spectrum of activity and is one of the most widely used chemotherapeutic drugs as first-line treatment. Indeed, DOX is a very interesting example of a drug for which several nanosized delivery systems have been developed over the years. While it is true that some of these systems are already in the market, it is also true that research on this subject remains very active and that there is a continuing search for new solutions. In this sense, this review takes the example of doxorubicin, not so much with the focus on the drug itself, but rather as a case study around which very diverse and imaginative nanotechnology approaches have emerged.

Synthesis of a Clay-Based Nanoagent for Photonanomedicine

Photo-induced cancer therapies, mainly including photothermal therapy (PTT) and photodynamic therapy (PDT), have attracted numerous attentions owing to the high selectivity, convenience, and few side effects. However, single PTT usually requires high laser power density, and single PDT usually needs a high photosensitizer dosage. Herein, a kind of composite nanocarrier based on clay (laponite)-polypyrrole (LP) nanodisks was synthesized via the in situ polymerization of pyrrole in the interlayer space of laponite. LP composite nanodisks were then coated with polyvinylpyrrolidone (PVP) to form the LP-PVP (LPP) composite nanodisks which show an excellent colloidal stability and in vitro and in vivo biocompatibility. The interlayer space of LPP can be further used for the loading of Chlorin e6 (Ce6), with an ultrahigh loading capacity of about 89.2%. Furthermore, the LPP nanocarrier can enhance the PDT effect of Ce6 under the irradiation of a 660 nm laser, through enhancing its solubility and cellular uptake amount. Besides, it was found that LPP nanodisks exhibit a more outstanding photothermal performance under a 980 nm near-infrared laser (NIR) than a 808 nm NIR laser, with the photothermal conversion efficiency of 45.7 and 27.7%, respectively. The in vitro and in vivo tumor therapy results evidently confirm that the Ce6-loaded LPP nanodisks have a combined tumor PTT and PDT effect, which can significantly suppress the tumor malignant proliferation.

Synthesis, Formulation, and Characterization of Doxorubicin-Loaded Laponite/Oligomeric Hyaluronic Acid-Aminophenylboronic Acid Nanohybrids and Cytological Evaluation against MCF-7 Breast Cancer Cells

As a synthetic clay material, laponite RDS (LR) was investigated as an effective drug carrier as a result of the special nanodisk structure together with the negative-charged surface to achieve enhanced cellular uptake and targeted delivery. In this research work, the synthesized oligomeric hyaluronic acid-aminophenylboronic acid (oHA-APBA) was entangled onto LR nanodisks to fabricate a valid targeted platform for breast cancer therapy. Briefly, through the formation of amide bonds, 3-APBA was connected to the chain of oHA with a substituted ratio of 4.0 ± 0.2% to synthesize oHA-APBA copolymer. Thereafter, doxorubicin (DOX) was inserted into the interlayer space of LR by the way of the ion exchange process, followed by an assembly with oHA-APBA as a targeted protection layer. The satisfactory drug encapsulation efficiency (> 80%) and narrow size distribution were achieved. The in vitro drug release study demonstrated the release of DOX from DOX@LR/oHA-APBA was sustained and acid dependent. In addition, after fitting the drug cumulative release of DOX@LR/oHA-APBA under different pH conditions with several kinetic models, it was identified that drug release from DOX@LR/oHA-APBA nanohybrids at pH 5.0 was mainly dependent on both diffusion and ion exchange effects. However, under the condition of pH 7.4, the drug was most efficiently released by diffusion effect. Importantly, DOX@LR/oHA-APBA showed remarkable cellular uptake and intracellular drug distribution in MCF-7 cells, which were consistent with inhibitory ability against MCF-7 cells. Hence, the high DOX loading capacity and enhanced cellular tracking can enlighten LR/oHA-APBA as an effective drug delivery carrier for breast cancer therapy.

Nucleic Acid-Based Dual Cross-Linked Hydrogels for in Situ Tissue Repair via Directional Stem Cell Migration

In situ tissue repair holds great potential as a cell-free regenerative strategy. A critical aspect of this approach is the selection of cell instructive materials that can efficiently regulate the defect microenvironment via the release of chemoattractant factors to mobilize and recruit endogenous stem cells toward the site of implantation. Here we report the design of a DNA-based hydrogel as a drug delivery platform for the sustained release of a promising chemoattractant, SDF-1α. The hydrogel is composed of chemically cross-linked DNA strands, which are bridged via silicate nanodisks (nSi). Silicate nanodisks electrostatically interact with the negatively charged DNA backbone resulting in the formation of a dual cross-linked nanocomposite hydrogel with a combination of chemical and physical cross-link points. The formulated nanocomposites display enhanced elasticity and mechanical toughness as compared to their nonsilicate containing counterparts. Moreover, the electrostatic interaction between nSi and SDF-1α leads to sustained release of the chemokine from the hydrogels. The in vitro bioactivity assays confirm the retention of chemotactic properties of the protein after its release. Overall, the dual cross-linked DNA-based hydrogel platform could be potentially used as a cell-instructive material for the recruitment of host stem cells to guide the process of in situ tissue repair.