In vitro cytocompatibility of one-dimensional and two-dimensional nanostructure-reinforced biodegradable polymeric nanocomposites

Microenvironment Restruction of Emerging 2D Materials and their Roles in Therapeutic and Diagnostic Nano-Bio-Platforms

Engineering advanced therapeutic and diagnostic nano-bio-platforms (NBPFs) have emerged as rapidly-developed pathways against a wide range of challenges in antitumor, antipathogen, tissue regeneration, bioimaging, and biosensing applications. Emerged 2D materials have attracted extensive scientific interest as fundamental building blocks or nanostructures among material scientists, chemists, biologists, and doctors due to their advantageous physicochemical and biological properties. This timely review provides a comprehensive summary of creating advanced NBPFs via emerging 2D materials (2D-NBPFs) with unique insights into the corresponding molecularly restructured microenvironments and biofunctionalities. First, it is focused on an up-to-date overview of the synthetic strategies for designing 2D-NBPFs with a cross-comparison of their advantages and disadvantages. After that, the recent key achievements are summarized in tuning the biofunctionalities of 2D-NBPFs via molecularly programmed microenvironments, including physiological stability, biocompatibility, bio-adhesiveness, specific binding to pathogens, broad-spectrum pathogen inhibitors, stimuli-responsive systems, and enzyme-mimetics. Moreover, the representative therapeutic and diagnostic applications of 2D-NBPFs are also discussed with detailed disclosure of their critical design principles and parameters. Finally, current challenges and future research directions are also discussed. Overall, this review will provide cutting-edge and multidisciplinary guidance for accelerating future developments and therapeutic/diagnostic applications of 2D-NBPFs.

Antipathogenic properties and applications of low-dimensional materials

A major health concern of the 21st century is the rise of multi-drug resistant pathogenic microbial species. Recent technological advancements have led to considerable opportunities for low-dimensional materials (LDMs) as potential next-generation antimicrobials. LDMs have demonstrated antimicrobial behaviour towards a variety of pathogenic bacterial and fungal cells, due to their unique physicochemical properties. This review provides a critical assessment of current LDMs that have exhibited antimicrobial behaviour and their mechanism of action. Future design considerations and constraints in deploying LDMs for antimicrobial applications are discussed. It is envisioned that this review will guide future design parameters for LDM-based antimicrobial applications.

Sonochemically N-functionalized graphene oxide towards optically active photoluminescent bioscaffold

Herein, Nitrogen functionalized graphene oxide (N-f-GrO) has been synthesized using the sonochemical method. 2-Aminopyrimidine (APD) was used as a precursor for covalent functionalization with graphene oxide [f-(APD)GrO] as N-f-GrO which was ascertained with XPS. The involvement of arylamine group and formation of covalent bond over GrO surface was confirmed with high resolution C1s spectrum of f-(APD)GrO. Also, the signature of N1s peak in the survey spectrum of f-(APD)GrO has endorsed the surface modification of GrO through covalent functionalization. A bathochromic shift was observed for f-(APD)GrO in UV and enhanced weight loss of 91.39% at 191.80 °C, confirms a facile functionalization of GrO via formation of amide bond, where the terminal -OH portal of carboxylic group is substituted by 2-Aminopyrimidine. Moreover, the formation of f-(APD)GrO was investigated with various analytical techniques like Raman, XRD and FTIR. The surface morphology and topography have been understood by using HRTEM/SAED, AFM, and SEM analysis. The synthesized f-(APD)GrO shows potential optically active photoluminescence properties and higher potency towards biological insight. The identified photoluminescence (PL) peaks at 3.78, 3.21 2.01 and 1.64 eV indicate photon emission including an orange optical transition at 2.01 eV. The multiple peaks in a PL spectrum are due to radiative and non-radiative recombinations which are also associated with excess hole (h⁺)-electron (e^-) trapping on the surface to restrict the recombinations of e^- and h⁺. The biological activity of N-f-GrO has been explored with Sulforhodamine B (SRB) assay on HaCaT and Vero cell lines. The concentration-dependent cell viabilities have been observed a maximum at 20 µg/ml for HaCaT and at 10 µg/ml for Vero cell lines at testing concentration range of 10-80 μg mL^-1. The significant morphological impact on cell lines confirms the cytocompatibility behaviour. Therefore, the synergistic impact of various properties of f-(APD)GrO can be further explored to study its significance as nanocarrier for photosensitive biomedical response.

Surface-Induced in Situ Sonothermodynamically Controlled Functionalized Graphene Oxide for in Vitro Cytotoxicity and Antioxidant Evaluations

Graphene oxide-based advanced functional materials offer an ultimate solution for wider biomedical applications. In situ thermodynamically ultrasound-assisted direct covalent functionalization of graphene oxide (GO) with sulfanilamide (SA) has synthesized f-(SA)GO. Raman spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction pattern, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have analyzed the f-(SA)GO structure for functional activities, expressed through synergistic impact of heteroatomic domains (SIHAD). The TGA of GO and f-(SA)GO demonstrates their total weight losses of 82.0 and 61.1%, respectively. Enhanced thermal stability of f-(SA)GO infers an exothermic behavior obtained with DSC. The surface-induced in situ thermodynamically controlled nonspontaneous reaction for f-(SA)GO has facilitated calculations for activation energy (E a) = - 2.65 × 103 kJ mol-1 and Gibbs free energy (ΔG) = 8.3741 kJ mol-1, energetics for biological activities with sulforhodamine B assay on MCF-7 and Vero cell lines and antioxidant potential by free radical scavenging activity with DPPH (2,2-diphenyl-1-picrylhydrazyl). Cell viabilities are >89.8% for Vero and >90.1% for MCF-7 with f-(SA)GO over 10 to 80 μg mL-1. Its cytocompatibility infers establishment of a new material. The morphological effect on MCF-7 and Vero cell lines confirm its structurally stable biocompatibility. The SIHAD of f-(SA)GO scavenges radical activity, and its heteroatomic structure causes valuable physiochemical activities. f-(SA)GO could emerge as an advanced functional biomaterial for structurally and thermally stable biocompatible nanocoatings.

Enhanced Osteogenesis by Molybdenum Disulfide Nanosheet Reinforced Hydroxyapatite Nanocomposite Scaffolds

The advances in the arena of biomedical engineering enable us to fabricate novel biomaterials that provide a suitable platform for rapid bone regeneration. Herein, we have investigated the in vitro and in vivo osteogenic differentiation, proliferation, and bone regeneration capability of molybdenum disulfide nanosheets (MoS₂NSs) reinforced HAP nanocomposite scaffolds. The MG-63 cells were incubated with HAP and HAP/MoS₂NSs nanocomposite and followed for various cellular activities. The cells incubated with HAP@2 shows higher cell adhesion, cell proliferation, and alkaline phosphatase activity (ALP) in contrast to HAP. The in vivo and in vitro results of the increased ALP level confirm that HAP@2 promotes osteogenic differentiation. This improved osteogenesis was validated with upregulation of osteogenic marker viz. transcription factor, RUNX-2 (∼34 fold), collagen-1 (∼15 fold), osteopontin (∼11 fold), osteocalcin (∼20 fold), and bone morphogenetic protein-2 (∼12 fold) after 12 week postimplantation in comparison to drilled. The X-ray imaging demonstrates that HAP@2 implants promote rapid osteogenesis and bioresorbability than HAP and drilled. The outcomes of the present study provide a promising tool for the regeneration of bone deformities, without using any external growth factor.

Two-dimensional graphene oxide-reinforced porous biodegradable polymeric nanocomposites for bone tissue engineering

This study investigates the mechanical properties and in vitro cytotoxicity of two-dimensional (2D) graphene oxide nanoribbons and nanoplatelets (GONRs and GONPs) reinforced porous polymeric nanocomposites. Highly porous poly(propylene fumarate) (PPF) nanocomposites were prepared by dispersing 0.2 wt % single- and multiwalled SONRs (SWGONRs and MWGONRs) and GONPs. The mechanical properties of scaffolds were characterized using compression testing and in vitro cytocompatibility was assessed using QuantiFlour assay for cellularity and PrestoBlue assay for cell viability. Immunofluorescence was used to assess collagen-I expression and deposition in the extracellular matrix. Porous PPF scaffolds were used as a baseline control and porous single and multiwalled carbon nanotubes (SWCNTs and MWCNTs) reinforced nanocomposites were used as positive controls. Results show that incorporation of 2D graphene nanomaterials leads to an increase in the mechanical properties of porous PPF nanocomposites with following the trend: MWGONRs > GONPs > SWGONRs > MWCNTs > SWCNTs > PPF control. MWGONRs showed the best enhancement of compressive mechanical properties with increases of up to 26% in compressive modulus (i.e., Young's modulus), ~60% in yield strength, and ~24% in the ultimate compressive strength. Addition of 2D nanomaterials did not alter the cytocompatibility of porous PPF nanocomposites. Furthermore, PPF nanocomposites reinforced with SWGONRs, MWGONRs, and GONPs show an improvement in the adsorption of collagen-I compared to PPF baseline control. The results of this study show that 2D graphene nanomaterial reinforced porous PPF nanocomposites possess superior mechanical properties, cytocompatibility, and increased protein adsorption. The favorable cytocompatibility results opens avenues for in vivo safety and efficacy studies for bone tissue engineering applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1143-1153, 2019.

Poly(ester amide) derived from municipal polyethylene terephthalate waste guided stem cells for osteogenesis

A novel poly(ester amide) was synthesized by using recycled poly(ethylene terephthalate) waste and soybean oil and other renewable resources for bone tissue engineering applications.

Fabrication of fasudil hydrochloride modified graphene oxide biocomposites and its defensive effect acute renal injury in septicopyemia rats

This investigation aspired to the impacts of intraperitoneal injection of suspended graphene oxide-bovine serum albumin (GO-BSA) biocomposite blended in fasudil (FSD)-against intense renal damage in septicopyemia rodent's models. It was picked a model of acute renal injury by an intraperitoneal organization of fasudil. Our outcomes demonstrated that few markers of renal capacity, for example, blood urea nitrogen (BUN), creatinine (SC), and intratubular waste levels were altogether diminished essentially in fasudil blended GO-BSA intraperitoneally infusion groups during the first week, showing that GO-BSA has an uncommon ability to ensure FSD discharges. Additionally, surprisingly, while rats got GO-BSA intraperitoneally, biomedical examination demonstrated the fruitful decrease of blood urea nitrogen and creatinine blood factors showing that GO-BSA has an uncommon ability alone to repair the acute renal injury. It appears that GO-BSA can adsorb ECM proteins and encourages their exchange to the intense renal damage tissue and expands its repair speed, in addition, GO-BSA ensures the FSD and along these lines the helpful adequacy of the FSD in intense renal damage enhanced by the grip of living cells to GO-BSA biocomposites. It could be inferred that GO-BSA material improves the rate of achievement of FSD conveys in intense renal damage in septicopyemia animals.

Multivalent Interactions between 2D Nanomaterials and Biointerfaces

2D nanomaterials, particularly graphene, offer many fascinating physicochemical properties that have generated exciting visions of future biological applications. In order to capitalize on the potential of 2D nanomaterials in this field, a full understanding of their interactions with biointerfaces is crucial. The uptake pathways, toxicity, long-term fate of 2D nanomaterials in biological systems, and their interactions with the living systems are fundamental questions that must be understood. Here, the latest progress is summarized, with a focus on pathogen, mammalian cell, and tissue interactions. The cellular uptake pathways of graphene derivatives will be discussed, along with health risks, and interactions with membranes-including bacteria and viruses-and the role of chemical structure and modifications. Other novel 2D nanomaterials with potential biomedical applications, such as transition-metal dichalcogenides, transition-metal oxide, and black phosphorus will be discussed at the end of this review.

In Vitro Bioactivity of One- and Two-Dimensional Nanoparticle-Incorporated Bone Tissue Engineering Scaffolds

This study investigates the effect of incorporation of one- or two-dimensional nanoparticles with distinct composition and morphology on the bioactivity of biodegradable, biocompatible polymer matrices. 0.2 wt% multiwalled carbon nanotubes, multiwalled graphene nanoribbons, graphene oxide nanoplatelets (GONPs), molybdenum disulfide nanoplatelets (MSNPs), or tungsten disulfide nanotubes (WSNTs) were uniformly dispersed in poly(lactic-co-glycolic acid) (PLGA) polymer. PLGA or nanoparticle-incorporated PLGA were then incubated with simulated body fluid (SBF) under physiological conditions for 1, 3, 7, or 14 days. Apatite collection on control and incorporated scaffolds was assessed. All groups showed apatite precipitate on the surface after 1 day of SBF incubation. After 14 days of SBF incubation, scaffolds incorporated with GONPs, MSNPs, or WSNTs showed significantly higher phosphate accumulation compared to PLGA scaffolds. Scaffolds incorporated with GONPs, MSNPs, or WSNTs should be studied in vivo to further investigate potential bioactivity, leading to enhanced integration and tissue repair at the bone-implant interface.

Boron nitride nanotubes and nanoplatelets as reinforcing agents of polymeric matrices for bone tissue engineering

This study investigates the mechanical properties and in vitro cytotoxicity of one- and two-dimensional boron nitride nanomaterials-reinforced biodegradable polymeric nanocomposites. Poly(propylene fumarate) (PPF) nanocomposites were fabricated using crosslinking agent N-vinyl pyrrolidone and inorganic nanomaterials: boron nitride nanotubes (BNNTs) and boron nitride nanoplatelets (BNNPs) dispersed at 0.2 wt % in the polymeric matrix. The incorporation of BNNPs and BNNTs resulted in a ∼38 and ∼15% increase in compressive (Young's) modulus, and ∼31 and ∼6% increase in compressive yield strength compared to PPF control, respectively. The nanocomposites showed a time-dependent increased protein adsorption for collagen I protein. The cytotoxicity evaluation of aqueous BNNT and BNNP dispersions (at 1-100 μg/mL concentrations) using murine MC3T3 preosteoblast cells showed ∼73-99% viability. The cytotoxicity evaluation of media extracts of nanocomposites before crosslinking, after crosslinking, and upon degradation (using 1×-100× dilutions) showed dose-dependent cytotoxicity responses. Crosslinked nanocomposites showed excellent (∼79-100%) cell viability, cellular attachment (∼57-67%), and spreading similar to cells grown on the surface of tissue culture polystyrene control. The media extracts of degradation products showed a dose-dependent cytotoxicity. The favorable cytocompatibility results in combination with improved mechanical properties of BNNT and BNNP nanocomposites opens new avenues for further in vitro and in vivo safety and efficacy studies towards bone tissue engineering applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 406-419, 2017.

Graphene oxide as a scaffold for bone regeneration

Graphene oxide (GO), the oxidized form of graphene, holds great potential as a component of biomedical devices, deriving utility from its ability to support a broad range of chemical functionalities and its exceptional mechanical, electronic, and thermal properties. GO composites can be tuned chemically to be biomimetic, and mechanically to be stiff yet strong. These unique properties make GO-based materials promising candidates as a scaffold for bone regeneration. However, questions still exist as to the compatibility and long-term toxicity of nanocarbon materials. Unlike other nanocarbons, GO is meta-stable, water dispersible, and autodegrades in water on the timescale of months to humic acid-like materials, the degradation products of all organic matter. Thus, GO offers better prospects for biological compatibility over other nanocarbons. Recently, many publications have demonstrated enhanced osteogenic performance of GO-containing composites. Ongoing work toward surface modification or coating strategies could be useful to minimize the inflammatory response and improve compatibility of GO as a component of medical devices. Furthermore, biomimetic modifications could offer mechanical and chemical environments that encourage osteogenesis. So long as care is given to assure their safety, GO-based materials may be poised to become the next generation scaffold for bone regeneration. WIREs Nanomed Nanobiotechnol 2017, 9:e1437. doi: 10.1002/wnan.1437 For further resources related to this article, please visit the WIREs website.

Toxicology of graphene-based nanomaterials

Graphene based nanomaterials possess remarkable physiochemical properties suitable for diverse applications in electronics, telecommunications, energy and healthcare. The human and environmental exposure to graphene-based nanomaterials is increasing due to advancements in the synthesis, characterization and large-scale production of graphene and the subsequent development of graphene based biomedical and consumer products. A large number of in vitro and in vivo toxicological studies have evaluated the interactions of graphene-based nanomaterials with various living systems such as microbes, mammalian cells, and animal models. A significant number of studies have examined the short- and long-term in vivo toxicity and biodistribution of graphene synthesized by variety of methods and starting materials. A key focus of these examinations is to properly associate the biological responses with chemical and morphological properties of graphene. Several studies also report the environmental and genotoxicity response of pristine and functionalized graphene. This review summarizes these in vitro and in vivo studies and critically examines the methodologies used to perform these evaluations. Our overarching goal is to provide a comprehensive overview of the complex interplay of biological responses of graphene as a function of their physiochemical properties.

Three-dimensional macroporous graphene scaffolds for tissue engineering

The assembly of carbon nanomaterials into three-dimensional (3D) porous scaffolds is critical to harness their unique physiochemical properties for tissue engineering and regenerative medicine applications. In this study, we report the fabrication, characterization, and in vitro cytocompatibility of true 3D (>1 mm in all three dimensions), macroscopic (3-8 mm in height and 4-6 mm in diameter), chemically cross-linked graphene scaffolds prepared via radical initiated thermal cross-linking of single- and multiwalled graphene oxide nanoribbons (SWGONRs and MWGONRs). SWGONR and MWGONR scaffolds possess tunable porosity (∼65-80%) and interconnected macro-, micro-, and nanoscale pores. Human adipose derived stem cells (ADSCs) and murine MC3T3 preosteoblast cells show good cell viability on SWGONR and MWGONR scaffolds after 1, 3, and 5 days comparable to 3D poly(lactic-co-glycolic) acid (PLGA) scaffolds. Confocal live-cell imaging showed that cells were metabolically active and could spread on SWGONR and MWGONR scaffolds. Immunofluorescence imaging showed the presence of focal adhesion protein vinculin and expression of cell proliferation marker Ki-67 suggesting that cells could attach and proliferate on SWGONR and MWGONR scaffolds. These results indicate that cross-linked SWGONR and MWGONR scaffolds are cytocompatible and opens-avenues toward the development of 3D multifunctional graphene scaffolds for tissue engineering applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 73-83, 2017.

Biomedical Uses for 2D Materials Beyond Graphene: Current Advances and Challenges Ahead

Currently, a broad interdisciplinary research effort is pursued on biomedical applications of 2D materials (2DMs) beyond graphene, due to their unique physicochemical and electronic properties. The discovery of new 2DMs is driven by the diverse chemical compositions and tuneable characteristics offered. Researchers are increasingly attracted to exploit those as drug delivery systems, highly efficient photothermal modalities, multimodal therapeutics with non-invasive diagnostic capabilities, biosensing, and tissue engineering. A crucial limitation of some of the 2DMs is their moderate colloidal stability in aqueous media. In addition, the lack of suitable functionalisation strategies should encourage the exploration of novel chemical methodologies with that purpose. Moreover, the clinical translation of these emerging materials will require undertaking of fundamental research on biocompatibility, toxicology and biopersistence in the living body as well as in the environment. Here, a thorough account of the biomedical applications using 2DMs explored today is given.

Porous three-dimensional carbon nanotube scaffolds for tissue engineering

Assembly of carbon nanomaterials into three-dimensional (3D) architectures is necessary to harness their unique physiochemical properties for tissue engineering and regenerative medicine applications. Herein, we report the fabrication and comprehensive cytocompatibility assessment of 3D chemically crosslinked macrosized (5-8 mm height and 4-6 mm diameter) porous carbon nanotube (CNT) scaffolds. Scaffolds prepared via radical initiated thermal crosslinking of single- or multiwalled CNTs (SWCNTs and MWCNTs) possess high porosity (>80%), and nano-, micro-, and macroscale interconnected pores. MC3T3 preosteoblast cells on MWCNT and SWCNT scaffolds showed good cell viability comparable to poly(lactic-co-glycolic) acid (PLGA) scaffolds after 5 days. Confocal live cell and immunofluorescence imaging showed that MC3T3 cells were metabolically active and could attach, proliferate, and infiltrate MWCNT and SWCNT scaffolds. SEM imaging corroborated cell attachment and spreading and suggested that cell morphology is governed by scaffold surface roughness. MC3T3 cells were elongated on scaffolds with high surface roughness (MWCNTs) and rounded on scaffolds with low surface roughness (SWCNTs). The surface roughness of scaffolds may be exploited to control cellular morphology and, in turn, govern cell fate. These results indicate that crosslinked MWCNTs and SWCNTs scaffolds are cytocompatible, and open avenues toward development of multifunctional all-carbon scaffolds for tissue engineering applications.