Amphiphilic polymer-mediated formation of laponite-based nanohybrids with robust stability and pH sensitivity for anticancer drug delivery

Advances in Nanotechnology for Enhancing the Solubility and Bioavailability of Poorly Soluble Drugs

This manuscript offers a comprehensive overview of nanotechnology's impact on the solubility and bioavailability of poorly soluble drugs, with a focus on BCS Class II and IV drugs. We explore various nanoscale drug delivery systems (NDDSs), including lipid-based, polymer-based, nanoemulsions, nanogels, and inorganic carriers. These systems offer improved drug efficacy, targeting, and reduced side effects. Emphasizing the crucial role of nanoparticle size and surface modifications, the review discusses the advancements in NDDSs for enhanced therapeutic outcomes. Challenges such as production cost and safety are acknowledged, yet the potential of NDDSs in transforming drug delivery methods is highlighted. This contribution underscores the importance of nanotechnology in pharmaceutical engineering, suggesting it as a significant advancement for medical applications and patient care.

Dynamics of Nanocomposite Hydrogel Alignment during 3D Printing to Develop Tissue Engineering Technology

Taking inspiration from spider silk protein spinning, we developed a method to produce tough filaments using extrusion-based 3D bioprinting and salting-out of the protein. To enhance both stiffness and ductility, we have designed a blend of partially crystalline, thermally sensitive natural polymer gelatin and viscoelastic G-polymer networks, mimicking the components of spider silk. Additionally, we have incorporated inorganic nanoparticles as a rheological modifier to fine-tune the 3D printing properties. This self-healing nanocomposite hydrogel exhibits exceptional mechanical properties, biocompatibility, shear thinning behavior, and a well-controlled gelation mechanism for 3D printing.

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.

Polymer-based nanosystems and their applications in bone anticancer therapy

The mortality rate of bone cancer has witnessed a substantial reduction in recent years, all thanks to the advent of advanced cancer treatment modalities such as surgical intervention, radiation, and chemotherapy. Nevertheless, these popular modalities come with a set of clinical challenges, including non-specificity, side effects, and drug intolerance. In recent years, polymer-based nanosystems have emerged as a promising solution in bone anti-cancer therapy by virtue of their unique physical and chemical properties. These nanosystems can be tailored for use in different drug release mechanisms for therapeutic implementations. This review delves into the efficacy of these therapy applications in bone cancer (with a focus on one of the most common types of cancers, Osteosarcoma) treatment and their correlation with the properties of polymer-based nanosystems, in addition to their interaction with the tumor microenvironment and the biological milieu.

Intranasally Co-administered Berberine and Curcumin Loaded in Transfersomal Vesicles Improved Inhibition of Amyloid Formation and BACE-1

Selective permeability of the blood-brain barrier restricts the treatment efficacy of neurologic diseases. Berberine (BBR) and curcumin (CUR)-loaded transferosomes (TRANS) were prepared for the effective management of Alzheimer's disease (AD). The study involved the syntheses of BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS by the film hydration method. Vesicles were characterized to ensure the formation of drug-loaded vesicles and their in vivo performance. The particle sizes of BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS were 139.2 ± 7, 143.4 ± 8, and 165.3 ± 6.5 nm, respectively. The presence of diffused rings in the SED image indicates the crystalline nature of the payload. Low surface roughness in an AFM image could be associated with the presence of a surface lipid. BBR-CUR-TRANS showed 41.03 ± 1.22 and 47.79 ± 3.67% release of BBR and 19.22 ± 1.47 and 24.67 ± 1.94% release of CUR, respectively, in phosphate buffer saline (pH 7.4) and acetate buffer (pH 4.0). Formulations showed sustained release of both loaded drugs. BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS exhibited a lower percentage of hemolysis than pure BBR and CUR, indicating the safety of the payload from delivery vesicles. Lower percentages of binding were recorded from BBR-CUR-TRANS than BBR-TRANS and CUR-TRANS. Acetylcholinesterase inhibition activity of the prepared transferosomes was greater than that of pure drugs, which are thought to have good cellular penetration. The spatial memory was improved in treated mice models. The level of malondialdehyde decreased in AD animals treated with BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS, respectively, as compared to the scopolamine-induced AD animals. BBR-CUR-TRANS-treated animals showed the highest decrease in the NO level. The catalase level was significantly restored in scopolamine-intoxicated animals treated with BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS. The immunohistochemistry result suggested that the BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS have significantly decreased the regulation of expression of BACE-1 through antioxidant activity. In conclusion, the study highlights the utility of formulated transferosomes as promising carriers for the co-delivery of drugs to the brain.

Laponite/amoxicillin-functionalized PLA nanofibrous as osteoinductive and antibacterial scaffolds

In this study, Amoxicillin (AMX) was loaded on laponite (LAP) nanoplates and then immobilized on the surface of electrospun polylactic acid (PLA) nanofibers to fabricate scaffolds with osteoinductive and antibacterial activities. The highest loading efficiency (49%) was obtained when the concentrations of AMX and LAP were 3 mg/mL and 1 mg/mL, respectively. FTIR and XRD spectroscopies and zeta potentiometry confirmed the successful encapsulating of AMX within LAP nanoplates. The immobilization of AMX-loaded LAPs on the surface of PLA nanofibers was verified by SEM and FTIR spectroscopy. In vitro release study showed a two-phase AMX release profile for the scaffolds; an initial burst release within the first 48 h and a later sustained release up to 21 days. In vitro antibacterial tests against Staphylococcus aureus and Escherichia coli presented the ability of scaffolds to inhibit the growth of both bacteria. The biocompatibility assays revealed the attachment and viability of human bone marrow mesenchymal stem cells (hBMSCs) cultured on the surface of scaffolds (p ≤ 0.05). The increased ALKALINE PHOSPHATASE (ALP) activity (p ≤ 0.001), calcium deposition, and expression of ALP and OSTEONECTIN genes indicated the osteoinductivity of functionalized scaffolds for hBMSCs. These LAP/AMX-functionalized scaffolds might be desirable candida for the treatment of bone defects.

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.

"Cluster Bomb" Based on Redox-Responsive Carbon Dot Nanoclusters Coated with Cell Membranes for Enhanced Tumor Theranostics

Designing intelligent stimuli-responsive nanoplatforms that are integrated with a biological membrane system and nanomaterials to realize efficient imaging and therapy of tumors still remains to be challenging. Herein, we report a unique strategy to prepare redox-responsive yellow fluorescent carbon dot nanoclusters (y-CDCs) loaded with anticancer drug doxorubicin (DOX) and coated with the cancer cell membrane (CCM) for precision fluorescence imaging and homologous targeting chemotherapy of tumors. The y-CDs with a size of 7.2 nm were first synthesized via a hydrothermal method and crosslinked to obtain redox-responsive y-CDCs with a size of 150.0 nm. The formulated y-CDCs were physically loaded with DOX with an efficiency of up to 81.0% and coated with CCM to endow them with antifouling properties, immune escape ability to escape from macrophage uptake, and homologous targeting capability to cancer cells. Within the reductive tumor microenvironment, the y-CDCs with quenched fluorescence can dissociate to form single y-CDs with recovered fluorescence and improved tumor penetration ability and simultaneously release DOX from the "cluster bomb", thus realizing efficient targeted tumor fluorescence imaging and chemotherapy. The designed y-CDCs/DOX@CCM may represent an updated nanomedicine formulation based on CDs for improved theranostics of different types of tumors.

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.

Nanoclay Reinforced Biomaterials for Mending Musculoskeletal Tissue Disorders

Nanoclay-reinforced biomaterials have sparked a new avenue in advanced healthcare materials that can potentially revolutionize treatment of musculoskeletal defects. Native tissues display many important chemical, mechanical, biological, and physical properties that engineered biomaterials need to mimic for optimal tissue integration and regeneration. However, it is time-consuming and difficult to endow such combinatorial properties on materials via feasible and nontoxic procedures. Fortunately, a number of nanomaterials such as graphene, carbon nanotubes, MXenes, and nanoclays already display a plethora of material properties that can be transferred to biomaterials through a simple incorporation procedure. In this direction, the members of the nanoclay family are easy to functionalize chemically, they can significantly reinforce the mechanical performance of biomaterials, and can provide bioactive properties by ionic dissolution products to upregulate cartilage and bone tissue formation. For this reason, nanoclays can become a key component for future orthopedic biomaterials. In this review, we specifically focus on the rapidly decreasing gap between clinic and laboratory by highlighting their application in a number of promising in vivo studies.

Development of Nanosilicate-Hydrogel Composites for Sustained Delivery of Charged Biopharmaceutics

Nanocomposite hydrogels containing two-dimensional nanosilicates (NS) have emerged as a new technology for the prolonged delivery of biopharmaceuticals. However, little is known about the physical-chemical properties governing the interaction between NS and proteins and the release profiles of NS-protein complexes in comparison to traditional poly(ethylene glycol) (PEG) hydrogel technologies. To fill this gap in knowledge, we fabricated a nanocomposite hydrogel composed of PEG and laponite and identified simple but effective experimental conditions to obtain sustained protein release, up to 23 times slower as compared to traditional PEG hydrogels, as determined by bulk release experiments and fluorescence correlation spectroscopy. Slowed protein release was attributed to the formation of NS-protein complexes, as NS-protein complex size was inversely correlated with protein diffusivity and release rates. While protein electrostatics, protein concentration, and incubation time were important variables to control protein-NS complex formation, we found that one of the most significant and less appreciated variable to obtain a sustained release of bioactive proteins was the buffer chosen for preparing the initial suspension of NS particles. The buffer was found to control the size of nanoparticles, the absorption potential, morphology, and stiffness of hydrogels. From these studies, we conclude that the PEG-laponite composite fabricated is a promising new platform for sustained delivery of positively charged protein therapeutics.

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.

Advances of smart nano-drug delivery systems in osteosarcoma treatment

Nanotechnology has recently become popular due to its potential for biomedical applications, especially for cancer treatment. Nanotechnology, featuring responsiveness to stimuli and stable drug release, has been widely used for the delivery of chemotherapeutic drugs, which are commonly used in the treatment of osteosarcoma. Smart stimuli-responsive nanotechnology is expected to improve the treatment of osteosarcoma. Herein, we focus on the latest research on nanomaterials in treating osteosarcoma that respond to internal and external stimuli. We also discuss nanocarriers with targeting ligands and the use of smart nanotechnology to partially reverse the multidrug resistance of osteosarcoma.

The thermal/pH-sensitive drug delivery system encapsulated by PAA based on hollow hybrid nanospheres with two silicon source

The synthesis of drug delivery systems based on hollow mesoporous silica nanoparticles (MSNs) is still a major challenge. In this work, the hollow hybrid MSNs were successfully prepared by cetyltrimethylammonium bromide-directed sol-gel process and one-step hydrothermal treatment process. The hollow hybrid MSNs had hybrid ethane-bridged frameworks with the uniform particle size (250 nm) and mesoporous pore diameter (3.7 nm). The polyacrylic acid (PAA) encapsulated drug delivery system based on hollow hybrid MSNs was prepared by using silanization, surface modification, doxorubicin hydrochloride (DOX) loading, and PAA coating. Drug encapsulation and release behavior at different temperatures and pH were studied by using DOX as a model guest molecule. The results displayed that the modified hollow ethane-bridged MSNs possessed good biocompatibility and excellent thermal/pH-dual-sensitive drug release property. This novel thermal/pH-sensitive drug delivery system based on hollow ethane-bridged MSNs has the advantages of feasible synthesis, no cytotoxicity, and good drug loading capacity, which may have potential applications in the anticancer therapy.

Hierarchical Incorporation of Surface-Functionalized Laponite Clay Nanoplatelets with Type I Collagen Matrix

Unraveling the interaction mechanisms of type I collagen with various inorganic nanoparticles is of pivotal importance to construct collagen-based bionanocomposites with hierarchical structures for biomedical, pharmaceutical, and other industrial applications. In this study, synthetic two-dimensional Laponite nanoplatelets (LAP NPs) are surface-functionalized with tetrakis(hydroxymethyl) phosphonium sulfate (THPS) for reinforcing their incorporation with type I collagen matrix by focusing on the influences of the interactions on the hierarchical structures of the collagen. Our results indicate that the LAP NPs can be successfully surface-functionalized with THPS via covalent bonds between the amine-functionalized NPs and the hydroxymethyl groups of THPS. Moreover, the resulting NPs can be well dispersed into the collagen matrix and evenly bound onto the collagen fiber strands and between the collagen fibrils, preserving the native D-periodic banding patterns of the collagen fibrils. The formation of covalent and hydrogen bonds between the collagen and the functionalized NPs can stabilize the intrinsic triple-helical conformation of the collagen, conferring the resulting collagen-based nanocomposites with improved thermal stability and enhanced mechanical properties. We anticipate that a fundamental understanding of the interactions between the collagen and functionalized inorganic nanoparticles would contribute to the design, fabrication, and further application of hierarchical collagen-based bionanocomposites with multifunctions.

Brimonidine-LAPONITE® intravitreal formulation has an ocular hypotensive and neuroprotective effect throughout 6 months of follow-up in a glaucoma animal model

Intravitreal administration is widely used in ophthalmological practice to maintain therapeutic drug levels near the neuroretina and because drug delivery systems are necessary to avoid reinjections and sight-threatening side effects. However, currently there is no intravitreal treatment for glaucoma. The brimonidine-LAPONITE® formulation was created with the aim of treating glaucoma for extended periods with a single intravitreal injection. Glaucoma was induced by producing ocular hypertension in two rat cohorts: [BRI-LAP] and [non-bri], with and without treatment, respectively. Eyes treated with brimonidine-LAPONITE® showed lower ocular pressure levels up to week 8 (p < 0.001), functional neuroprotection explored by scotopic and photopic negative response electroretinography (p = 0.042), and structural protection of the retina, retinal nerve fibre layer and ganglion cell layer (p = 0.038), especially on the superior-inferior axis explored by optical coherence tomography, which was corroborated by a higher retinal ganglion cell count (p = 0.040) using immunohistochemistry (Brn3a antibody) up to the end of the study (week 24). Furthermore, delayed neuroprotection was detected in the contralateral eye. Brimonidine was detected in treated rat eyes for up to 6 months. Brimonidine-LAPONITE® seems to be a potential sustained-delivery intravitreal drug for glaucoma treatment.

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.

Effect of the supramolecular interactions on the nanostructure of halloysite/biopolymer hybrids: a comprehensive study by SANS, fluorescence correlation spectroscopy and electric birefringence

The structural properties of halloysite/biopolymer aqueous mixtures were firstly investigated by means of combining different techniques, including small-angle neutron scattering (SANS), electric birefringence (EBR) and fluorescence correlation spectroscopy (FCS). Among the biopolymers, non-ionic hydroxypropylcellulose and polyelectrolytes (anionic alginate and cationic chitosan) were selected. On this basis, the specific supramolecular interactions were correlated to the structural behavior of the halloysite/biopolymer mixtures. SANS data were analyzed in order to investigate the influence of the biopolymer adsorption on the halloysite gyration radius. In addition, a morphological description of the biopolymer-coated halloysite nanotubes (HNTs) was obtained by the simulation of SANS curves. EBR experiments evidenced that the orientation dynamics of the nanotubes in the electric field is influenced by the specific interactions with the polymers. Namely, both variations of the polymer charge and/or wrapping mechanisms strongly affected the HNT alignment process and, consequently, the rotational mobility of the nanotubes. FCS measurements with fluorescently labeled biopolymers allowed us to study the aqueous dynamic behavior of ionic biopolymers after their adsorption onto the HNT surfaces. The combination of EBR and FCS results revealed that the adsorption process reduces the mobility in water of both components. These effects are strongly enhanced by HNT/polyelectrolyte electrostatic interactions and wrapping processes occurring in the halloysite/chitosan mixture. The attained findings can be useful for designing halloysite/polymer hybrids with controlled structural properties.

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.

Core-shell tecto dendrimers formed via host-guest supramolecular assembly as pH-responsive intelligent carriers for enhanced anticancer drug delivery

The design of pH-sensitive supramolecular drug delivery systems for efficient antineoplastic drug delivery remains a huge challenge. Herein, we describe the development of pH-responsive core-shell tecto dendrimers (CSTDs) formed using benzimidazole (BM)-modified generation 3 (G3) poly(amidoamine) (PAMAM) dendrimers (G3.NHAc-BM) as a shell and β-cyclodextrin (CD)-modified G5 PAMAM dendrimers (G5.NHAc-CD) as a core. By virtue of the host-guest recognition and pH-responsiveness of BM/β-CD assembly, the pH-sensitive supramolecular CSTDs of G5.NHAc-CD/BM-G3.NHAc were formed and adopted to encapsulate the anticancer drug doxorubicin (DOX) via hydrophobic interactions for pH-responsive drug delivery applications. The synthesis of dendrimer derivatives and the loading of the DOX were well characterized via different methods. We show that the encapsulated DOX can be released in a sustained manner with a rapid release speed under a slightly acidic pH condition (pH < 6), which is similar to acidic tumor microenvironment. The enhanced intracellular release of DOX and improved anticancer activity of the drug-loaded pH-responsive CSTDs were demonstrated and compared with the control CSTDs formed without pH-responsiveness through flow cytometry and viability assays of cancer cells. Furthermore, the pH-sensitive CSTDs also showed efficient drug penetration and growth inhibition of three-dimensional tumor spheroids owing to the faster DOX release in an acidic pH environment. The pH-sensitive G5.NHAc-CD/BM-G3.NHAc CSTDs may be employed as a valuable intelligent delivery system for various anticancer drugs.

Printing bone in a gel: using nanocomposite bioink to print functionalised bone scaffolds

Free-form printing offers a novel biofabrication approach to generate complex shapes by depositing hydrogel materials within a temporary supportive environment. However, printed hydrogels typically lack the requisite mechanical properties and functionality of the desired tissue, limiting application and, more importantly, safety and efficacy of the implant. The study authors have developed an innovative nanoclay-based bioink to print high shape fidelity functional constructs for potential skeletal application. Laponite® (LAP) nanoclay was combined with gellan gum (GG) to generate a printable hydrogel that was highly stable in vitro, displayed limited swelling ability compared with the silicate-free control and remained stable over time. An agarose fluid gel was found to provide the requisite support for the deposition of the material ink and preservation of the printed structure before crosslinking. Printed C2C12 myoblasts remained viable and displayed extensive proliferation over 21 days in culture. Cell-laden scaffolds demonstrated functionality within 1 day of culture in vitro and that was preserved over 3 weeks. Analysis of absorption and release mechanisms from LAP-GG using model proteins (lysozyme and bovine serum albumin) demonstrated the retention capability of the clay-based materials for compound localisation and absence of burst release. Vascular endothelial growth factor ​was loaded within the agarose fluid gel and absorbed by the material ink via absorption during deposition. The 3D-printed constructs were implanted on the chorioallantoic membrane of a 10-day-old developing chick. Extensive and preferential vasculature infiltration was observed in LAP-GG-loaded vascular endothelial growth factor constructs compared with controls (p<0.01 and p<0.0001) after only 7 days of incubation. The current studies demonstrate, for the first time, the application of innovative LAP-GG 3D constructs in the generation of growth factor-loaded 3D constructs for potential application in skeletal tissue repair.

Hybrid mesoporous silica nanospheres modified by poly (NIPAM-co-AA) for drug delivery

The synthesis of drug delivery systems based on surface-modified mesoporous silica hollow structures remains a huge challenge. In this paper, we have obtained hollow mesoporous silica nanoparticles (MSNs) by surfactant directed sol-gel assisted hydrothermal treatment. The MSNs have the inorganic-organic hybrid frameworks with uniform diameter distribution (260 nm), and their specific surface area, mesoporous size and pore volume are 540 m² g^-1, 3.7 nm, 0.58 cm³ g^-1, respectively. It was proved that the preparation of hollow ethane-bridged nanospheres with two silicon source was due to the high crosslinking of the silicone interface and hydrothermal treatment, providing a new approach for the study of drug-loaded and controlled release behavior. Based on the synthesis of MSNs, MSNs were modified by methacryloxy propyl trimethoxyl silane (MPS) on the surface of MSNs. Then N-isopropylacryamide (NIPAM) and acrylic acid (AA) were grafted onto the surface of modified MSNs. The hollow ethane-bridged PNA-MSNs (poly (NIPAM-co-acrylic acid)-MSNs) with two silicon source were prepared successfully. Due to their distinctive hollow structure, PNA-MSNs demonstrated high drug encapsulation efficiency (70.4% ± 2.9%). The experiment results proved that the modified hollow nanoparticles not only had good biocompatibility and stability, but also possessed pH-/thermal-dual responsiveness in drug release.

2D Nanoclay for Biomedical Applications: Regenerative Medicine, Therapeutic Delivery, and Additive Manufacturing

Clay nanomaterials are an emerging class of 2D biomaterials of interest due to their atomically thin layered structure, charged characteristics, and well-defined composition. Synthetic nanoclays are plate-like polyions composed of simple or complex salts of silicic acids with a heterogeneous charge distribution and patchy interactions. Due to their biocompatible characteristics, unique shape, high surface-to-volume ratio, and charge, nanoclays are investigated for various biomedical applications. Here, a critical overview of the physical, chemical, and physiological interactions of nanoclay with biological moieties, including cells, proteins, and polymers, is provided. The state-of-the-art biomedical applications of 2D nanoclay in regenerative medicine, therapeutic delivery, and additive manufacturing are reviewed. In addition, recent developments that are shaping this emerging field are discussed and promising new research directions for 2D nanoclay-based biomaterials are identified.

Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement

The antimicrobial effects of Laponite nanoparticles with or without loading of the antimicrobial peptide LL-37 was investigated along with their membrane interactions. The study combines data from ellipsometry, circular dichroism, fluorescence spectroscopy, particle size/ζ potential measurements, and confocal microscopy. As a result of the net negative charge of Laponite, loading of net positively charged LL-37 increases with increasing pH. The peptide was found to bind primarily to the outer surface of the Laponite nanoparticles in a predominantly helical conformation, leading to charge reversal. Despite their net positive charge, peptide-loaded Laponite nanoparticles did not kill Gram-negative Escherichia coli bacteria or disrupt anionic model liposomes. They did however cause bacteria flocculation, originating from the interaction of Laponite and bacterial lipopolysaccharide (LPS). Free LL-37, in contrast, is potently antimicrobial through membrane disruption but does not induce bacterial aggregation in the concentration range investigated. Through LL-37 loading of Laponite nanoparticles, the combined effects of bacterial flocculation and membrane lysis are observed. However, bacteria aggregation seems to be limited to Gram-negative bacteria as Laponite did not cause flocculation of Gram-positive Bacillus subtilis bacteria nor did it bind to lipoteichoic acid from bacterial envelopes. Taken together, the present investigation reports several novel phenomena by demonstrating that nanoparticle charge does not invariably control membrane destabilization and by identifying the ability of anionic Laponite nanoparticles to effectively flocculate Gram-negative bacteria through LPS binding. As demonstrated in cell experiments, such aggregation results in diminished LPS-induced cell activation, thus outlining a promising approach for confinement of infection and inflammation caused by such pathogens.

The structure-property relationship in LAPONITE® materials: from Wigner glasses to strong self-healing hydrogels formed by non-covalent interactions

Rheology, small-angle X-ray scattering (SAXS), and dynamic light scattering (DLS) analysis, zeta potential measurement, scanning electron microscopy (SEM), and micro-FTIR and absorbance spectroscopy were used to enlighten the controversial literature about LAPONITE® materials. Our data suggest that pristine LAPONITE® in water does not form hydrogels induced by the so-called "house of cards" assembly, but rather forms Wigner glasses governed by repulsive forces. Ionic interactions between anisotropic LAPONITE® nanodiscs, sodium polyacrylate and inorganic salts afforded hydrogels that were transparent, self-standing, moldable, strong, and biocompatible with shear-thinning and self-healing behavior. An extensive study on the role of salts in the gelification process dictates a trend that relates the valence of cations with the viscoelastic properties of the bulk material (G' values follow the trend, monovalent < divalent < trivalent). These hydrogels present G' values up to 5.1 × 104 Pa, which are considered high values for non-covalent hydrogels. Hydrogels crosslinked with sodium phosphate salts are biocompatible, and might be valid candidates for injectable drug delivery systems due to their shear-thinning behavior with rapid self-healing after injection.

Hyaluronic acid-modified cationic nanoparticles overcome enzyme CYP1B1-mediated breast cancer multidrug resistance

Aim: Enzyme CYP1B1 (CYP1B1) is usually overexpressed in multidrug resistance (MDR) breast cancer cells, which could metabolically inactivate docetaxel (DTX). Materials & methods: The cationic core–shell nanoparticles (hyaluronic acid/polyethyleneimine nanoparticles [HA/PEI NPs]) modified with hyaluronic acid (HA) were developed and coloaded with DTX and α-napthtoflavone (ANF, a CYP1B1 inhibitor) to overcome MDR in breast cancer induced by CYP1B1. Physicochemical characterization, MDR reversing effect in vitro and pharmacokinetics in vivo of HA/PEI NPs were evaluated. Results: The HA/PEI NPs exhibited spherical morphology with size of (193.6 ± 3.1) nm. The HA/PEI NPs could reverse MDR effectively by downregulating the expression of CYP1B1. The HA/PEI NPs improved the bioavailability of DTX. Conclusion: The HA/PEI NPs might be a promising strategy to overcome CYP1B1-mediated breast cancer MDR.

Laponite®: A key nanoplatform for biomedical applications?

Laponite® is a synthetic smectite clay that already has many important technological applications, which go beyond the conventional uses of clays in pharmaceutics and cosmetics. In biomedical applications, particularly in nanomedicine, this material holds great potential. Laponite® is a 2-dimensional (2D) nanomaterial composed of disk-shaped nanoscale crystals that have a high aspect ratio. These disks can strongly interact with many types of chemical entities (from small molecules or ions, to natural or synthetic polymers, to different inorganic nanoparticles) and are also easily functionalized and readily degraded in the physiological environment giving rise to non-toxic and even bioactive products. This review will highlight the potential of Laponite® as a nanomaterial in the fields of drug delivery, bioimaging, tissue engineering and regenerative medicine. New concepts, as well as novel innovative materials that stand out from the usual ones due to the unique properties of Laponite®, will also be presented and discussed.

Integrating 3D-printed PHBV/Calcium sulfate hemihydrate scaffold and chitosan hydrogel for enhanced osteogenic property

We developed the 3D-printed poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/calcium sulfate hemihydrate (PHBV/CaSH) scaffolds by using fused deposition modelling (FDM) technique and then coated the scaffolds with chitosan (CS) acetic acid solution. After drying and neutralization, CS hydrogel was formed on the surface of the scaffolds. The resultant PHBV/CaSH/CS scaffolds could promote the adhesion and proliferation of rat bone marrow stromal cells (rBMSCs) and enhance the osteogenesis of rBMSCs by up-regulating the expression level of osteogenic genes compared to the PHBV and PHBV/CaSH scaffolds. In vivo studies further demonstrated the PHBV/CaSH/CS scaffolds could effectively promote new bone formation. Therefore, integrating 3D-printed PHBV/CaSH scaffold and CS hrydogel represents a novel strategy to promote osteogensis property, showing full potential for bone defects repair.

Sequence-Dependent Peptide Surface Functionalization of Metal-Organic Frameworks

We report a noncovalent surface functionalization technique for water-stable metal-organic frameworks using short peptide sequences identified via phage display. Specific frameworks-binding peptides were identified for crystalline Zn(MeIM)₂ (MeIM: 2-methylimidazole, ZIF-8), semiamorphous Fe-BTC (BTC: 1,3,5-benzene-tricarboxylate), and Al(OH)(C₄H₂O₄) (MIL-53(Al)-FA, FA: fumaric acid), and their thermodynamic binding affinities and specificities were measured. Electron microscopy, powder X-ray diffraction, and gas adsorption analysis confirmed that the peptide-functionalized frameworks retained similar characteristics compared to their as-synthesized counterparts. Confocal laser-scanning microscopy demonstrated that peptide was localized on the surface of the frameworks, whereas surface area measurements showed no evidence of pore blockage. Finally, we measured the pH-dependent release of fluorescein from peptide-functionalized frameworks and discovered that peptide binding can attenuate fluorescein release by improving framework stability under low pH conditions. Our results demonstrate that phage display can be used as a general method to identify specific peptide sequences with strong binding affinity to water-stable metal-organic frameworks and that these peptides can alter drug release kinetics by affecting framework stability in aqueous environments.

A luminescent europium-dipicolinic acid nanohybrid for the rapid and selective sensing of pyrophosphate and alkaline phosphatase activity

As a ubiquitous hydrolysis enzyme in phosphate metabolism, alkaline phosphatase (ALP) is a significant biomarker in laboratory research and clinic diagnosis. Herein, we report a highly water-soluble Eu(DPA)3@Lap nanohybrid material for the rapid and selective assay of PPi and ALP through a luminescence off-on recognition process. Eu(DPA)3@Lap was successfully prepared in an aqueous solution, and it exhibited strong luminescence emission, high photostability, and long lifetime. More interestingly, the strong luminescence of Eu(DPA)3@Lap can be remarkably quenched by Cu2+ due to the high impetus of coordination between the DPA ligand and Cu2+ ion. Using Cu2+ as a signal transducer, the luminescence could be recovered upon the addition of PPi ion owing to the formation of a Cu2+-PPi complex; thus, a luminescence turn-on assay for PPi ions was realized. Utilizing the ability of Cu2+ to differentiate between PPi and Pi, a convenient and straightforward luminescence assay for ALP activity was accomplished based on the specific dephosphorylation of PPi to Pi. To the best of our knowledge, this elaborate luminescence sensing system constitutes the first luminescent nanohybrid material based on a europium organic complex for ALP activity assay. Furthermore, the recognition process of PPi and ALP was completed in a convenient and facile mix-and-readout manner, and it revealed significant potential in point of care testing.

LAPONITE® nanoplatform functionalized with histidine modified oligomeric hyaluronic acid as an effective vehicle for the anticancer drug methotrexate

The synthetic clay material, LAPONITE® (LAP), having a nanodisk structure together with a negatively charged surface, has been used for effective drug encapsulation by virtue of its interlayer space.

Improving the carrier stability and drug loading of unimolecular micelle-based nanotherapeutics for acid-activated drug delivery and enhanced antitumor therapy

Nanomedicines based on unimolecular micelles (UMs) have shown unique advantages such as high micellar stability, programmed cargo delivery and enhanced therapeutic efficiency.

An RGD-modified hollow silica@Au core/shell nanoplatform for tumor combination therapy

The combination of chemotherapy and photothermal therapy (PTT) in multifunctional nanoplatforms to improve cancer therapeutic efficacy is of great significance while it still remains to be a challenging task. Herein, we report Au nanostar (NS)-coated hollow mesoporous silica nanocapsules (HMSs) with surface modified by arginine-glycine-aspartic acid (RGD) peptide as a drug delivery system to encapsulate doxorubicin (DOX) for targeted chemotherapy and PTT of tumors. Au NSs-coated HMSs core/shell nanocapsules (HMSs@Au NSs) synthesized previously were conjugated with RGD peptide via a spacer of polyethylene glycol (PEG). We show that the prepared HMSs@Au-PEG-RGD NSs are non-cytotxic in the given concentration range, and have a DOX encapsulation efficiency of 98.6±0.7%. The designed HMSs@Au-PEG-RGD NSs/DOX system can release DOX in a pH/NIR laser dual-responsive manner. Importantly, the formed HMSs@Au-PEG-RGD NSs/DOX nanoplatform can specifically target cancer cells overexpressing α_vβ₃ intergrin and exert combination chemotherapy and PTT efficacy to the cells in vitro and a xenografted tumor model in vivo. Our results suggest that the designed HMSs@Au-PEG-RGD NSs/DOX nanoplatform may be used for combination chemotherapy and PTT of tumors.

STATEMENT OF SIGNIFICANCE

We demonstrate a convenient approach to preparing a novel RGD-targeted drug delivery system of HMSs@Au-PEG-RGD NSs/DOX that possesses pH/NIR laser dual-responsive drug delivery performance for combinational chemotherapy and PTT of tumors. The developed Au NS-coated HMS capsules have both merits of HMS capsules that can be used for high payload drug loading and Au NSs that have NIR laser-induced photothermal conversion efficiency (70.8%) and can be used for PTT of tumors.