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Effective hemorrhage control is indispensable for life-threatening emergencies in defense fields and civilian trauma. During major injuries, hemostatic agents are applied externally to mimic and accelerate the natural hemostasis process. Commercially available topical hemostatic agents are associated with several limitations

Hypothesis Modeling three-dimensional (3D) in vitro culture systems recapitulating spatiotemporal characteristics of native tumor-mass has shown tremendous potential as a pre-clinical tool for drug screening. However, their applications in clinical settings are still limited due to inappropriate recapitulation of tumor topography, culture instability, and poor durability of niche support. Experiments Here, we have fabricated a bio-active silk composite scaffold assimilating tunable silk from Bombyx mori and – arginine-glycine-aspartate (RGD) rich silk from Antheraea assama to provide a better 3D-matrix for breast (MCF 7) and liver (HepG2) tumoroids. Cellular mechanisms underlying physiological adaptations in 3D constructs and subsequent drug responses were compared with conventional monolayer and multicellular spheroid culture. Findings Silk composite matrix assists prolonged growth and high metabolic activity (Cytochrome P450 reductase) in breast and liver 3D-tumoroids. Enhanced stemness expression (Cell surface adhesion receptor; CD44, Aldehyde dehydrogenase 1) and epithelial-mesenchymal-transition markers (E-cadherin, Vimentin) at transcript and protein levels demonstrate that bio-active matrix-assisted 3D environment augmenting metastatic potential in tumoroids. Together, enhanced secretion of Transforming growth factor β (TGFβ), anchorage-independency, and colony-forming potential of cells in the 3D-tumoroids further corroborates the aggressive behavior of cells. Moreover, the multilayered 3D-tumoroids exhibit decreased sensitivity to some known anticancer drugs (Doxorubicin and Paclitaxel). In conclusion, the bio-active silk composite matrix offers an advantage in developing robust and sustainable 3D tumoroids for a high-throughput drug screening platform.

Control promotion and prevention of platelet adhesion are important for various biomedical applications. In the past, surface topography and chemical modifications have been commonly utilized for tailoring the promotion and prevention of platelet adhesion. Recently, lotus-leaf-inspired superhydrophobicity has appeared as an efficient avenue to prevent platelet adhesion. However, such extreme water repellent interfaces fail to perform upon prolonged and continuous exposure to aqueous phase. In this communication, the strategic use of a catalyst-free 1,4-conjugate addition reaction between amine and acrylate allowed us to investigate the impact of two distinct underwater oil-wettability on platelet adhesion activity. While underwater superoleophobicity inhibited platelet-adhesion, a highly aggregated fibrous network of adhered platelets was observed on underwater superoleophilic coating. Further, this biocompatible and haemocompatible underwater superoleophobic multilayer coating was deposited on a commercially available catheter tube to examine its potential towards the prevention of platelet attachment.

Catalyst-free and readily chemically reactive functional coatings that have immense prospects in various relevant applications are unprecedentedly synthesized directly using naturally existing bovi...

The aim of present study was to develop a pH responsive rate controlling polymer by acrylamide grafting onto pullulan. Grafting was performed using free radical induced microwave assisted irradiation technique using ceric ammonium nitrate as free radical inducer. Acrylamide grafted pullulan (Aam-g-pull) was characterized by Fourier transform infrared spectroscopy, solid state 13C nuclear magnetic resonance and field emission scanning electron microscopy. In vitro enzymatic degradation of Aam-g-pull showed degradation of 22.45% after 8 h with degradation rate constant (k) of 0.019 min−1. In vitro cytotoxicity test did not show cell viability below 80% on HepG2 cell line. Pirfenidone tablets were prepared by utilizing wet granulation method using Aam-g-pull as the only rate controlling polymer. The tablets were characterized in terms of in-process quality control parameters like weight variation, hardness, assay, and in vitro dissolution study. The dissolution study showed that the cumulative drug release in phosphate buffer pH 6.8 (rel3 h = 44.12 ± 0.56%) got a significant jump as compared to the release in 0.1 N hydrochloric acid (rel2 h = 26.78 ± 0.23%), confirming the material to be pH responsive. Aam-g-pull can be used as pH responsive rate controlling polymer.

The aim of present study was to develop controlled release formulation of pirfenidone using acrylamide grafted pullulan. Interpenetrating polymer network (IPN) microspheres were prepared using acrylamide grafted pullulan and PVA utilizing glutaraldehyde assisted water-in-oil emulsion crosslinking method. IPN microspheres were characterized by FTIR, solid state 13C NMR and XRD spectroscopy. In vitro enzymatic degradation study showed 34.30% degradation after 24 h with degradation rate constant of 0.0088 min−1. In vitro biocompatibility test showed no changes in cellular morphology and cell adherence to microspheres, indicating its biocompatible nature. The release exponent value of all formulations was less than 0.45, indicating the release mechanism to be Fickian diffusion. Finally, in vivo pharmacokinetic study showed longer Tmax (1.16 h) and greater AUC value (10037.76 ng h/mL,) as compared to Pirfenex® (Tmax = 0.5 h; AUC = 4310.45 ng h/mL,). The results indicated that the prepared formulation could successfully control the drug release for prolonged time period.

Reconstruction of native tissue's anatomical and biophysical milieu dictates the success of tissue engineered graft's cellular fate. Herein, we report a facile fabrication procedure to replicate the anatomical and biomechanical features of annulus fibrosus (AF) tissue. A seamless, full thickness disc-like angle-ply construct was fabricated using silk fibroin (SF) protein. To mimic the gradual transition of mechanical gradient from inner to outer region of native AF tissue, SF proteins from two different sources (namely Bombyx mori, BM SF as mulberry, and Antheraea assamensis, AA SF and Philosamia ricini, PR SF as non-mulberry) were blended that provided differential mechanical and cell binding properties. Fabricated constructs were physicochemically and biologically characterized. The seeded porcine AF cells were found to proliferate and align along the lamellar pores as visualized through staining. Gene expression study concluded higher expression of collagen-I with enhancement of mechanical properties, whereas an opposite trend was observed for both collagen-II and aggrecan. Overall, the angle-ply construct with tailored mechanical properties supported cellular alignment and proliferation, and modulated the extracellular matrix (ECM) deposition forming a functional AF tissue like construct, thus providing a robust foundation as an alternative tissue engineered strategy in intervertebral disc (IVD) regeneration for future replacement therapy. Keywords: Silk, Annulus fibrosus, Intervertebral disc, Biomaterial, Tissue engineering

Hydrogels have received considerable attention in the field of tissue engineering because of their unique structural and compositional resemblance to the highly hydrated human tissues. In addition, controlled fabrication processes benefit them with desirable physicochemical features for injectability in minimally invasive manner and cell survival within hydrogels. Formulation of biologically active hydrogels with desirable characteristics is one of the prerequisites for successful applications like nucleus pulposus (NP) tissue engineering to address disc degeneration. To achieve such a benchmark, in this study, two naturally derived silk fibroin proteins (Bombyx mori, BM SF; and Antheraea assamensis, AA SF) were blended together to allow self-assembly and transformation to hydrogels in absence of any cross-linker or external stimuli. A comprehensive study on sol-gel transition of fabricated hydrogels in physiological fluid microenvironment (pH, temperature, and ionic strength) was conducted using optical and fluorescence analysis. Tunable gelation time (∼8-40 min) was achieved depending on combinations. The developed hydrogels were validated by extensive physicochemical characterizations which include confirmation of secondary structure, surface morphology, swelling and degradation. Mechanical behavior of the hydrogels was further analyzed in various in vitro-physiological-like conditions with varying pH, ionic strength, diameter, storage time, and strain values to determine their suitability in native physiological environments. Rheological study, cytocompatibility using primary porcine NP cells and ex vivo biomechanics of hydrogels were explored to validate their in situ applicability in minimally invasive manner toward potential disc regeneration therapy.

The osteochondral healthcare market is driven by the increasing demand for affordable and biomimetic scaffolds. To meet this demand, silk fibroin (SF) from Bombyx mori and Antheraea assamensis is used to fabricate a biphasic scaffold, with fiber-free and fiber-reinforced phases, stimulating cartilage and bone revival. The fabrication is a facile reproducible process using single polymer (SF), for both phases, designed in a continuous and integrated manner. Physicochemical and mechanical scaffold characterization, display interconnected pores with differential swelling and tunable degradation. The compressive modulus values, extend to 40 kPa and 25%, for tensile strain, at elongation. The scaffold support, for growth and proliferation of chondrocytes and osteoblasts, for respective cartilage and bone regeneration, is verified from in vitro assessment. Up-regulation of alkaline phosphatase (ALP) activity, extracellular matrix secretion and gene expression are significant; with acceptable in vitro immune response. Upon implantation in rabbit osteochondral defects for 8 weeks, the histological and micro-CT examinations show biphasic scaffolds significantly enhance regeneration of cartilage and subchondral bone tissues, as compared to monophasic scaffolds. The regenerated bone mineral density (BMD) ranges from 600-700 mg hydroxyapatite (HA) per cm3. The results, therefore, showcase the critically positive characteristics of in vitro ECM deposition, and in vivo regeneration of osteochondral tissue by this hierarchically structured biphasic scaffold.

Extended and controlled release of more than a single bioactive molecule, simultaneously, from the same biocompatible matrix is challenging to achieve. However, this is important for combating various severe challenges (drug resistance, improved efficacy, etc.) related to drug delivery. In the recent past, the meta-stable trapped air (in the lotus leaf inspired artificial interfaces), which attributed to the extreme water repellency in biomimicked heirarchical (consisted of micro/nano features) interfaces, was unprecedentedly exploited for addressing multiple relevant aspects related to drug delivery (e.g., multiple drug release, tunable drug release, dose control through post-loading of drug molecules, etc.). A biocompatible polymeric material that is (a) synthesized using a one-step covalent and featured gelation of a single polymer and (b) capable of tailoring with a wide range of water wettabilities, was exploited for post loading both hydrophilic and hydrophobic small molecules from a wide variety (less polar, more polar, nonpolar) of organic solvents. Such small molecules loaded polymeric materials continued to display durable nature-inspired bulk wettability and provided simultaneous co-release of two different bioactive drug molecules (i.e., doxorubicin (DOX, anticancer drug) and tetracycline (TC, antibacterial drug)), over 6 months. Moreover, the release extent (from hours to months) of these small molecules was successfully tuned by controlling the water wettability of the single porous polymeric material. The released drug molecules remained bioactive and capable of inhibiting the proliferation of cancer cells (MG-63 (human osteosarcoma) and MDA-MB-231 (human breast adenocarcinoma)) and microorganisms (S. aureus and E. coli). These results provide a facile basis for developing a more potent and multifunctional drug release system for prospective biomedical applications.

Correction for ‘Simultaneous and controlled release of two different bioactive small molecules from nature inspired single material’ by Adil M. Rather et al., J. Mater. Chem. B, 2018, 6, 7692–7702.

In general, lotus leaf and rose petal-inspired wettabilities are artificially developed through the integration of hierarchical topography and essential chemical functionality. However, a fundamental and important aspect of this nature inspired wettability is not yet addressed; between the hierarchical topography and essential chemical modulation, which is the more sensitive parameter for this nature inspired special wettability? The design of a common approach for tailoring both the hierarchical topography and chemical functionalities is highly essential for investigating such a relevant fundamental aspect; however the synthesis of such a material is extremely difficult in reality. In the current computational study, the Michael addition reaction between unsaturated ester and primary amine groups was found to be facilitated in the presence of alkali metal ions. Interestingly, the mixture of branched polyethyleneimine (BPEI) and dipentaerythritol pentaacrylate (5Acl) in ethanol transformed into a chemically reactive polymeric monolith with tailored hierarchical features—based on the selection of appropriate alkali metal ions in the reaction mixture. The current study investigates the impact of the change in hierarchy in the topography on the nature inspired super-wettability—keeping the chemical functionality of the hierarchical topography intact. On the other hand, the inherent chemical reactivity of the hierarchical interfaces allowed us to examine the change in the chemical modulation—independently and precisely. The post-covalent modification of the hierarchical topography with longer and shorter hydrocarbon tails has a significant impact in controlling the metastable trapped air in the artificially biomimicked interfaces, and eventually controls the Wenzel, Cassie–Baxter and Cassie–Wenzel transition states. This current approach also allows us to modulate other relevant physical properties in the material—including the shrinkage of the material after the removal of the reaction solvent and compressive modulus. The materials with optimized physical properties were successfully exploited in the separation and collection of different forms of oil spills through both selective absorption process and gravity driven filtration process, even under practically relevant severe settings. Such a facile and general approach for tailoring both the chemical functionality and topography could be of potential interest for developing various functional and smart materials—including tissue engineering, patterned interfaces, etc.

Recapitulation of the form and function of complex tissue organization using appropriate biomaterials impacts success in tissue engineering endeavors. The annulus fibrosus (AF) represents a complex, multilamellar, hierarchical structure consisting of collagen, proteoglycans, and elastic fibers. To mimic the intricacy of AF anatomy, a silk protein-based multilayered, disc-like angle-ply construct was fabricated, consisting of concentric layers of lamellar sheets. Scanning electron microscopy and fluorescence image analysis revealed cross-aligned and lamellar characteristics of the construct, mimicking the native hierarchical architecture of the AF. Induction of secondary structure in the silk constructs was confirmed by infrared spectroscopy and X-ray diffraction. The constructs showed a compressive modulus of 499.18 ± 86.45 kPa. Constructs seeded with porcine AF cells and human mesenchymal stem cells (hMSCs) showed ∼2.2-fold and ∼1.7-fold increases in proliferation on day 14, respectively, compared with initial seeding. Biochemical analysis, histology, and immunohistochemistry results showed the deposition of AF-specific extracellular matrix (sulfated glycosaminoglycan and collagen type I), indicating a favorable environment for both cell types, which was further validated by the expression of AF tissue-specific genes. The constructs seeded with porcine AF cells showed ∼11-, ∼5.1-, and ∼6.7-fold increases in col Iα 1, sox 9, and aggrecan genes, respectively. The differentiation of hMSCs to AF-like tissue was evident from the enhanced expression of the AF-specific genes. Overall, the constructs supported cell proliferation, differentiation, and ECM deposition resulting in AF-like tissue features based on ECM deposition and morphology, indicating potential for future studies related to intervertebral disc replacement therapy.

Artificial bioinspired superhydrophobicity, which is generally developed through appropriate optimization of chemistry and hierarchical topography, is being recognized for its immense prospective applications related to environment and healthcare. Nevertheless, the weak interfacial interactions that are associated with the fabrication of such special interfaces often provide delicate biomimicked wettability, and the embedded antifouling property collapses on exposure to harsh and complex aqueous phases and also after regular physical deformations, including bending, creasing, etc. Eventually, such materials with potential antifouling property became less relevant for practical applications. Here, a facile, catalyst-free, and robust 1,4-conjugate addition reaction has been strategically exploited for appropriate covalent integration of modified graphene oxide to developing polymeric materials with (1) tunable mechanical properties and (2) durable antifouling property, which are capable of performing both in air and under oil. Furthermore, this approach provided a facile basis for (3) engineering a superhydrophobic monolith into arbitrary free-standing shapes and (4) decorating various flexible (metal, synthetic plastic, etc.) and rigid (glass, wood, etc.) substrates with thick and durable three-dimensional superhydrophobic coatings. The synthesized superhydrophobic monoliths and polymeric coatings with controlled mechanical properties are appropriate to withstand different physical insults, including twisting, creasing, and even physical erosion of the material, without compromising the embedded antiwetting property. The materials are also equally resistant to various harsh chemical environments, and the embedded antifouling property remained unperturbed even after continuous exposure to extremes of pH (pH 1 and pH 11), artificial sea water for a minimum of 30 days. These flexible and formable free-standing monoliths and stable polymeric coatings that are extremely water-repellent both in air and under oil, are of utmost importance owing to their suitability in practical circumstances and robust nature.

Structural recapitulation is one of the prime prerequisites for the biomechanics of a complex tissue like annulus fibrosus (AF). Design and fabrication of a biomimetic AF anatomical structure has garnered immense interest among tissue engineers owing to its potential in restoration of intervertebral disc function. Three-dimensional (3D) printing technology, in recent times has demonstrated its applicability to fabricate such a complex tissue architecture. Here, we fabricated angle-ply AF anatomical equivalents by depositing silk-carrageenan filaments in a layer-by-layer fashion using micro-extrusion based 3D printing strategy. The 3D-printed constructs exhibited fiber alignment that mimicks the native tissue when flipped by 90° across the periphery. The 3D printed constructs were physiochemically characterized including swelling and degradation. The cross-aligned structure was revealed by field-emission electron microscopy and fluorescence studies. Infrared spectroscopy analysis confirmed the induction of stable secondary β-sheet structure in the composite blend constructs. The 3D printed constructs exhibited higher mechanical strength (~78 kPa) than the native porcine AF tissue (~37 kPa). The constructs supported survival, growth and proliferation of both porcine primary AF cells (~1.43-fold) and adipose derived stem cells (ADSCs) (~1.32-fold) over the period of 14 days. Histological, biochemical and gene expression studies subsequently revealed the deposition of AF specific extracellular matrix on the constructs when maintained in chondrogenic medium. The developed biomaterial ink showed minimal-immunogenicity as depicted by the subcutaneous in vivo implantation assessment. Hence, the strategy adopted here to fabricate AF anatomical 3D printed equivalents may provide a new direction towards disc replacement therapy.

Owing to innate desirable features like biocompatibility, mechanical robustness, tunable biodegradability and amenability to multiple formatting, silk (christened as the ‘queen of textile’) has carved a unique niche in the realm of regenerative medicine. Silkworms, being the major source of silk are generally classified as mulberry and nonmulberry types depending on their feeding habit. Over the years, numerous patents and publications on mulberry based silk for various biomedical applications have been added to the scientific repository. In sharp contrast to this, the (immense) potential of the nonmulberry silk for biotechnological applications has been realised quite late and as such only a very few scientific documentations exists. In this article, we have presented the prospects and the recent endeavors to exploit nonmulberry silk (encompassing both fibroin and sericin) extracted from Antheraea mylitta ( tasar ) , Antheraea assamensis ( muga ) , Philosamia ricini ( eri ) etc. for fabrication of different formats of biomaterials (including, scaffolds, films, hydrogels, nanoparticles etc.) in applications like 3D tissue engineering (bone, skin etc.) and drug delivery, amongst others. The focus of the article is to highlight the prospective avenues of exploring nonmulberry silk in biomedical domain, reflected through some of our select research works along with few recent endeavors of our colleagues. The compilation is presented with the impetus that siphoning of non mulberry silk from the textile industry to the domain of biomaterial science can provide a fillip to the otherwise dwindling seri-industries of pockets like North East India.

Tunable repeated drug administration is often inevitable in a number of pathological cases. Reloadable 3D matrices for sustained drug delivery are predicted as a prospective avenue to realize this objective. This study was directed toward sonication-induced fabrication of novel reloadable Bombyx mori silk fibroin (SF) (4, 6, and 8 wt %) hydrogel, injected within 3D porous (8 wt %) scaffolds. The focus was to develop a dual-barrier reloadable depot system for sustained molecular cargo release. Both the varying SF concentration (4, 6, and 8 wt %) and the sonication time (30, 45, and 60 s) dictated the extent of cross-linking, β-sheet content, and porosity (1-10 μm) influencing the release behavior of model molecules. Release studies of model molecules (trypan blue, TB, 961 Da and bovine serum albumin, BSA, 66 kDa) for 28 days attested that the variations in their molecular weight, the matrix cross-linking density, and the scaffold-hydrogel interactions dictated the release behavior. The Ritger and Peppas equation was further fitted into the release behavior of model molecules from various SF matrices. The hybrid constructs exhibited high compressive strength along with in vitro compatibility using primary porcine chondrocytes and tunable enzymatic degradation as assessed for 28 days. The aptness of the constructs was evinced as a reloadable model molecule (BSA and fluorescein isothiocyanate-inulin, 3.9 kDa) depot system through UV-visible and fluorescence spectroscopic analyses. The novel affordable platform developed using silk scaffold-hydrogel hybrid constructs could serve as a sustained and reloadable drug depot system for administration of multiple and repeated drugs.

The present study was conducted to develop therapeutically effective controlled release formulation of pirfenidone (PFD) and explore the possibility to reduce the total administered dose and dosing regimen. For this purpose, pH-sensitive biomaterial was prepared by inducing carboxymethyl group on pullulan by Williamson ether synthesis reaction, and further, interpenetrating polymeric network microspheres were prepared by glutaraldehyde-assisted water-in-oil (w/o) emulsion cross-linking method, which showed higher swelling ratio in acidic and basic pH. The formation of microspheres was confirmed by different spectral characterization techniques, and thermal kinetic study indicated the formation of thermally stable microspheres. Cell viability and biocompatibility studies on hepatocellular carcinoma (HepG2) cell showed the polymeric matrix to be biocompatible. In vitro dissolution of optimized formulation (F5) showed releases of 54.09 and 76.37% in 0.1 N HCl after 2 h and phosphate buffer (pH 6.8) up to 8 h, respectively. In vivo performances of prepared microsphere and marketed product of PFD were compared in rabbit. Tmax (time taken to reach peak plasma concentration) was found to be achieved at 0.83 h, compared to 0.5 h for Pirfenex with no significant difference complementing the immediate action, while area under curve was significantly greater for optimized formulation (9768 ± 1300 ng h/mL) compared to Pirfenex (4311 ± 110 ng h/mL), complementing the sustained action. In vivo pharmacokinetic study suggested that the prepared microsphere could be a potential candidate for therapeutically effective controlled delivery of PFD used in dyspnea and cough management due to idiopathic pulmonary fibrosis.

The limited self-regenerative capacity of adult cartilage has steered the upsurge in tissue engineered replacements to combat the problem of osteoarthritis. In the present study, the potential of fiber-reinforced silk composites from mulberry (Bombyx mori) and non-mulberry (Antheraea assamensis) silk has been investigated for cartilage tissue engineering. The fabricated composites were physico-chemically characterized and analyzed for cellular viability, proliferation, extracellular matrix formation and immunocompatibility. Both mulberry and non-mulberry silk composites showed effective swelling (25%-30%) and degradation (10%-30%) behavior, owing to their interconnected porous nature. The non-mulberry fiber-reinforced composite scaffolds showed slower degradation (∼90% mass remaining) than mulberry silk over a period of 28 days. The reinforcement of silk fibers within silk solution resulted in an increased compressive modulus and stiffness (nearly eight-fold). The biochemical analysis revealed significant increase in DNA content, sulphated glycosaminoglycan (sGAG) (∼1.5 fold) and collagen (∼1.4 fold) in reinforced composites as compared to pure solution scaffolds (p ≤ 0.01). Histological and immunohistochemical (IHC) staining corroborated enhanced deposition of sGAG and localization of collagen type II in fiber-reinforced composites. This was further substantiated by real time polymerase chain reaction studies, which indicated an up-regulation (∼1.5 fold) of cartilage-specific gene markers namely collagen type II, sox-9 and aggrecan. The minimal secretion of tumor necrosis factor-α (TNF-α) by murine macrophages further demonstrated in vitro immunocompatibility of the scaffolds. Taken together, the results signified the potential of silk fiber-reinforced composite (particularly non-mulberry, A. assamensis) scaffolds as viable alternative biomaterial for cartilage tissue engineering.