Investigating the Effect of Polypyrrole-Gelatin/Silk Fibroin Hydrogel Mediated Pulsed Electrical Stimulation for Skin Regeneration.

In clinical practice to treat complex injuries, the application of electrical stimulation (ES) directly to the skin complicates the wound. In this work, the effect of a conductive hydrogel mediated electric field on skin regeneration is investigated. Polypyrrole incorporated matrices of gelatin and silk fibroin were prepared by two-step interfacial polymerization. The maximum electrical conductivity of 10-4 S cm-1 was achieved when 200 mM polypyrrole was loaded. Mechanically stable and cytocompatible hydrogels were evidenced to have antioxidant and blood compatible characteristics. Human dermal fibroblast cells responded to pulsed stimulation of 100 or 300 mV mm-1 as observed from the increased expressions of TGFß1, αSMA, and COLIAI genes. Further, the increase in the αSMA protein expression with the magnitude of electrical stimulation also suggested transdifferentiation of the fibroblast to myofibroblast. Moreover, Raman spectroscopy identified two fingerprint regions (collagen and lipid) to differentiate ES treated and nontreated samples. Therefore, the combination of hydrogels and electrical stimulation has potential therapeutic effects for accelerating the rate of skin regeneration.

Biosurfactant-Assisted Cu Doping of Brushite Coatings: Enhancing Structural, Electrochemical, and Biofunctional Properties.

Stainless steel (316L SS) has been widely used in orthopedic, cardiovascular stents, and other biomedical implant applications due to its strength, corrosion resistance, and biocompatibility. To address the weak interaction between steel implants and tissues, it is a widely adopted strategy to enhance implant performance through the application of bioactive coatings. In this study, Cu-doped brushite coatings were deposited successfully through pulse electrodeposition on steel substrates facilitated with a biosurfactant (BS) (i.e., surfactin). Further, the combined effect of various concentrations of Cu ions and BS on the structural, electrochemical, and biological properties was studied. The X-ray diffraction (XRD) confirms brushite composition with Cu substitution causing lattice contraction and a reduced crystallite size. The scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) studies reveal the morphological changes of the coatings with the incorporation of Cu, which is confirmed by X-ray photoelectron spectroscopy (XPS) and elemental mapping. The Fourier transform infrared (FTIR) and Raman spectroscopy confirm the brushite and Cu doping in the coatings, respectively. Increased surface roughness and mechanical properties of Cu-doped coatings were analyzed by using atomic force microscopic (AFM) and nanohardness tests, respectively. Electrochemical assessments demonstrate corrosion resistance enhancement in Cu-doped coatings, which is further improved with the addition of biosurfactants. In vitro biomineralization studies show the Cu-doped coating's potential for osseointegration, with added stability. The cytocompatibility of the coatings was analyzed using live/dead and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays; cell adhesion, proliferation, and migration studies were evaluated using SEM. Antibacterial assays highlight significant improvement in the antibacterial properties of Cu-doped coatings with BS. Thus, the developed Cu-doped brushite coatings with BS demonstrate their potential in the realm of biomedical implant technologies, paving the way for further exploration.

Development and performance evaluation of self-assembled pH-responsive curcumin-bacterial exopolysaccharide micellar conjugates as bioactive delivery system.

The present study reports the synthesis of micellar conjugates, wherein curcumin (Cur), a bioactive compound with poor bioavailability, was covalently bonded to a bacterial exopolysaccharide (EPS). These conjugates were synthesized by utilizing succinic acid that linked Cur to the pyranosyl moiety of the EPS. The Cur-EPS conjugates appeared as spherical micelles in aqueous solution and were found to have an average hydrodynamic diameter of 254 ± 2.7 nm. The micellar conjugates showed superior stability than Cur as evident from their negative surface charge (-27 ± 1.8 mV) and low polydispersity index (PDI) (0.33 ± 0.04). The in vitro studies on release kinetics helped elucidate the pH-responsive characteristics of the Cur-EPS conjugate, as 87.50 ± 1.45 % of Cur was released at an acidic pH of 5.6, in contrast to 30.15 ± 2.61 % at systemic pH of 7.4 at 150 h. The conjugates were hemocompatible and exhibited cytotoxic effect against the osteosarcoma cell line (MG-63) after 48 h treatment. They also demonstrated superior antibacterial, antibiofilm, and antioxidant activities in comparison to free Cur. Therefore, the Cur-EPS conjugates have potential pharmaceutical applications as therapeutic biomaterial that can be applied as a drug delivery system.

Bioactive self-assembling silk fibroin-sericin films for skin tissue engineering.

The quest for an ideal wound dressing material has been a strong motivation for researchers to explore novel biomaterials for this purpose. Such explorations have led to the extensive use of silk fibroin (SF) as a suitable polymer for several applications over the years. Unfortunately, another major silk protein-sericin has not received its due attention yet in spite of having favorable biological properties. In this study, we report an approach of blending SF and silk sericin (SS) without the usage of chemical crosslinkers is made possible by the usage of formic acid which evaporates to induceß-sheets formation to form cytocompatible films. Raman spectroscopy confirms the presence of SF/SS components in blend and formation ofß-sheet in films.In situ, gelation kinetics studies were conducted to understand the change in gelation properties with addition of sericin into SF. Methyl thiazolyl tetrazolium and live/dead assays were performed to study cellular attachment, viability and proliferation on SF/SS films. The antibacterial properties of SF/SS films were tested using Gram-negative and Gram-positive bacteria. The re-structured SF/SS films were stable, transparent, show good mechanical properties, antibacterial activity and cytocompatibility, therefore can serve as suitable biomaterial candidates for skin regeneration applications.

Natural Polymer-Based Thin Film Strategies for Skin Regeneration in Lieu of Regenerative Dentistry.

Wound healing (WH) is a complex and dynamic process that comprises of a series of molecular and cellular events that occur after tissue injury. The injuries of the maxillofacial and oral region caused by trauma or surgery result in undesirable WH such as delayed wound closure and formation of scar tissue. Skin tissue engineering (TE)/regeneration is an emerging approach toward faster, superior, and more effective resolution of clinically significant wounds effectively. A multitude of TE principles approaches are being put to action for the fabrication of hydrogels, electrospun sheets, 3D scaffolds, and thin films that can be used as wound dressings materials, sutures, or skin substitutes. Thin films are advantageous over other materials owing to their flexibility, ability to provide a barrier against external contamination, easy gaseous exchange, and easy monitoring of wounds. This review focuses on wound-dressing films and their significance and discusses various fabrication techniques. In addition, we explore various natural biopolymers that can be used for fabrication of skin TE materials. Impact Statement In this review article, critical evaluations of natural polymers used in skin regeneration were discussed. Further, the fabrication technology of the 2D and 3D material in wound healing were discussed.

Decrypting the role of predicted SARS-CoV-2 miRNAs in COVID-19 pathogenesis: A bioinformatics approach.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is a highly transmissible virus causing the ongoing global pandemic, COVID-19. Evidence suggests that viral and host microRNAs play pivotal roles in progression of such infections. The decisive impact of viral miRNAs and their putative targets in modulating the transcriptomic profile of its host, however remains unexplored. We hypothesized that the SARS-CoV-2 derived miRNAs can potentially play a contributory role in its pathogenicity and aid in its survival. A series of computational tools predicted 34 SARS-CoV-2 encoded miRNAs and their putative targets in the host. Immune and apoptotic pathways were identified as most enriched pathways. Further investigation using a dataset of SARS-CoV-2 infected cells (available from public repository- GSE150392) revealed that 46 genes related to immune and apoptosis-related functions were deregulated. Of these 46 genes, 42 genes were identified to be significantly up-regulated and 4 genes were down-regulated. In silico analysis revealed all of the these significantly down-regulated genes to be putative targets of 9 out of 34 of our predicted viral miRNAs. Overall, 123 out of 324 genes that are differentially regulated in SARS-CoV2 infected cells, and also identified as putative targets of viral miRNAs, were found to be significantly down-regulated. KEGG pathway analysis using these genes revealed p53 signaling as the most enriched pathway - a pathway that is known to influence immune responses. This study thus provides the theoretical foundation for the underlying molecular mechanisms involved in progression of viral pathogenesis.

MicroRNA expression patterns in HbE/ß-thalassemia patients: The passwords to unlock fetal hemoglobin expression in ß-hemoglobinopathies.

Hemoglobin E (HbE)/ß-thalassemia is a form of ß-hemoglobinopathy that is well-known for its clinical heterogeneity. Individuals suffering from this condition are often found to exhibit increased fetal hemoglobin (HbF) levels - a factor that may contribute to their reduced blood transfusion requirements. This study hypothesized that the high HbF levels in HbE/ß-thalassemia individuals may be guided by microRNAs and explored their involvement in the disease pathophysiology. The miRNA expression profile of hematopoietic progenitor cells in HbE/ß-thalassemia patients was investigated and compared with that of healthy controls. Using miRNA PCR array experiments, eight miRNAs (hsa-miR-146a-5p, hsa-miR-146b-5p, hsa-miR-148b-3p, hsa-miR-155-5p, hsa-miR-192-5p, hsa-miR-335-5p, hsa-miR-7-5p, hsa-miR-98-5p) were identified to be significantly up-regulated whereas four miRNAs (hsa-let-7a-5p, hsa-miR-320a, hsa-let-7b-5p, hsa-miR-92a-3p) were significantly down-regulated. Target analysis found them to be associated with several biological processes and molecular functions including MAPK and HIF-1 signaling pathways - the pathways known to be associated with HbF upregulation. Results of dysregulated miRNAs further indicated that miR-17/92 cluster might be of critical importance in HbF regulation. The findings of our study thus identify key miRNAs that can be extrinsically manipulated to elevate HbF levels in ß-hemoglobinopathies.

Extensive early mineralization of pre-osteoblasts, inhibition of osteoclastogenesis and faster peri-implant bone healing in osteoporotic rat model: principle effectiveness of bone-specific delivery of Tibolone as evaluated in vitro and in vivo.

Hydrophobic drug molecules pose a significant challenge in immobilization on super-hydrophobic metallic surfaces like conventional titanium implants. Pre-coating surface modifications may yield a better platform with improved wettability for such purposes. Such modifications, as depicted in this study, were hypothesized to provide the requisite roughness to assist deposition of polymers like silk fibroin (SF) as a drug-binding matrix in addition to significant improvement in early protein adsorption, which facilitates faster cellular adhesion and proliferation. A silk-based localized drug delivery module was developed on the titanium surface and tested for its surface roughness, wettability, biocompatibility and in vitro differentiation potential of cells cultured on the coated metallic surfaces with/without external supplementation of the active metabolite of Tibolone. Conditioning of the matrix-coated implants with osteogenic as well as osteoclastogenic media supplemented with Tibolone stimulated the expression of early osteogenic gene and calcium deposition in the extracellular matrix. Significant inhibition in resorptive activity was also observed in the presence of the drug. To assess the efficacy of localized delivery of Tibolone via topographically modified titanium implants for inducing early peri-implant bone formation, osteoporosis was artificially induced in rats subjected to bilateral ovariectomy and implants were placed thereafter. Bone-specific release of Tibolone through the biomimetic matrix in osteoporotic rats collectively indicated significant improvement in peri-implant bone growth after 2 and 4 weeks (p < 0.05 compared to dummy-coated implants). These findings demonstrate for the first time that Tibolone released from SF matrix-coated implants can accelerate the biological stability of bone fixtures.

Biomimetic silk fibroin and xanthan gum blended hydrogels for connective tissue regeneration.

Combination of naturally occurring materials instead of chemically synthesized products has always been an attractive proposition in the field of tissue engineering. In this study, silk fibroin (SF) and xanthan gum(XG) were physically crosslinked to form biocompatible hydrogels. SF/XG hydrogels were prepared using ultrasonication, which induces ß-sheets from random coils in SF solution and allows entrapment of heated XG chains homogeneously in the SF network. It is a novel way of blending SF and XG polymers which avoids the usage of chemical crosslinkers. SF/XG blended solutions were used at different ratios for the hydrogel formation. Scanning electron microscopy (SEM) and micro-computed tomography (MCT) were used for morphological analysis of the interconnected network and porosity of the scaffolds, respectively. Rheological studies were performed to understand the changes in mechanical properties due to the incorporation of XG into SF hydrogels. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of SF and XG moieties in the blend scaffolds. Additionally, thermal Analysis (TGA & DSC) established the homogenous mixture and presence of XG in the SF network without any phase separation. Furthermore, the MTT assay demonstrates the cytocompatibility of scaffolds using L929 fibroblast cells. Thus, fabricated SF/XG scaffolds could mimic natural cartilage ECM by exhibiting enhanced water swelling capacity and suitable porosity along with its cytocompatible studies, indicating its potential application in soft tissue engineering.

Tailorable hydrogel of gelatin with silk fibroin and its activation/crosslinking for enhanced proliferation of fibroblast cells.

Gelatin based hydrogel (Gel) possess remarkable cytocompatibility profile rendering it appropriate for tissue engineering applications. Herein, the questionable mechanical property of Gel was tuned by tailoring with different loading concentrations of silk fibroin (SF). The as tailored matrix was reconnoitred for its physico-mechanical, chemical and biological properties in order to investigate the effect of SF loading. Ethanol treatment lead to enhance ß-sheet formation of silk and subsequently, carbodiimide coupling was deployed to covalently crosslink the matrix. Substantial increase in cohesive energy with amplifying concentration of SF in the Gel matrix. As evidenced by Raman spectroscopy, right shift of the Amide I peak and stretching of COO- confirms activation of fibroin moiety along with crosslinking of gelatin, respectively. Moreover, with addition of SF, surface properties were tuned to attain maximum cell adhesion and proliferation. Further, MTT assay corroborated the same with definite increase in mitochondrial activities of L929 fibroblast cells for SF containing matrix as compared to its bare counterfeit while enhanced proliferation was confirmed by Rhodamine-DAPI staining. The alteration in mechanical and textural tribology of SF tailored Gel matrix certainly portrayed improved stability along with excellent cytocompatibility thus making it a plausible alternative in regenerative medicine.

A structured review of baculovirus infection process: integration of mathematical models and biomolecular information on cell-virus interaction.

The baculovirus expression vector system (BEVS) is an emerging tool for the production of recombinant proteins, vaccines and bio-pesticides. However, a system-level understanding of the complex infection process is important in realizing large-scale production at a lower cost. The entire baculovirus infection process is summarized as a combination of various modules and the existing mathematical models are discussed in light of these modules. This covers a systematic review of the present understanding of virus internalization, viral DNA replication, protein expression, budded virus (BV) and occlusion-derived virus (ODV) formation, few polyhedral (FP) and defective interfering particle (DIP) mutant formation, cell cycle modification and apoptosis during the viral infection process. The corresponding theoretical models are also included. Current knowledge regarding the molecular biology of the baculovirus/insect cell system is integrated with population balance and mass action kinetics models. Furthermore, the key steps for simulating cell and virus densities and their underlying features are discussed. This review may facilitate the further development and refinement of mathematical models, thereby providing the basis for enhanced control and optimization of bioreactor operation.