Synthesis of gallic acid-grafted epoxidized natural rubber and its role in self-healable flexible temperature sensors.

Developing a flexible temperature sensor with appreciable sensitivity is critical for advancing research related to flexible electronics. Although various flexible sensors are available commercially, most such temperature sensors are made from polymeric materials obtained from petrochemical resources. Such sensors will contribute to electronic waste and increase the carbon footprint after usage. While there are reports on various sensors made from sustainable polymers, research related to developing self-healable flexible temperature sensors made from sustainable polymers is significantly less. Herein, we report on developing a flexible temperature sensor made of gallic acid-grafted epoxidized natural rubber and multi-walled carbon nanotubes. Various spectroscopic and thermal techniques vetted the modification of the epoxidized natural rubber. The highest grafting of 20.9% was achieved in the selected window of stoichiometry. A self-healing behavior was achieved by leveraging the FeCl3 based metal-ligand crosslinking of the composite. The healing efficiency was noted to be 31.2% for the composite material. The fabricated sensor demonstrated an electrical resistance of 4.46 × 103 Ω, thereby warranting the composite to demonstrate an Ohmic behavior in the I-V plot. Appropriate data fitting suggested a variable range hopping mechanism as causation towards excellent electrical conduction. The temperature sensitivity and the thermal index of the developed sensor were noted to be -0.17% °C-1 and 781.2 K, respectively, in the temperature range of 30 °C to 50 °C. The proposed method of fabricating sustainable, high-strength, self-healable, and robust temperature sensors and conductors is a unique and value-added approach for next-generation flexible electronics.

Unusually high clarithromycin resistance in Mycobacterium abscessus subsp. abscessus isolated from human gastric epithelium.

Mycobacterium abscessus subsp. abscessus is a rapidly growing facultative intracellular pathogen that usually infects human lung and skin epithelium. Recently, we and another group have shown that it also has the potential to colonize human gastric epithelium, but its significance with respect to gastric diseases remains unclear. Although Helicobacter pylori still remains the only definite gastric pathogen, recent studies have shown that M. abscessus subsp. abscessus also has the potential to colonize human gastric epithelium. M. abscessus subsp. abscessus is known to exhibit multidrug resistance and clarithromycin has been used as the drug of choice. We aimed to determine the clarithromycin resistance profile of 117 (74 rough and 43 smooth) gastric M. abscessus subsp. abscessus strains and to detect the point mutations in rrl and erm (41) genes conferring the resistance. Our data showed 79.48% (19 smooth and 74 rough) of M. abscessus subsp. abscessus strains were resistant to clarithromycin (MIC90 ≤ 512 µg/mL), while 20.51% (24 smooth) were susceptible (MIC90 ≤ 8 µg/mL). Nucleotide sequence analysis of the rrl gene with reference strains of M. abscessus subsp. abscessus did not show any mutation that is relevant to the clarithromycin resistance. However, analysis of erm (41) gene showed that M. abscessus subsp. abscessus strains, which were susceptible to clarithromycin had C, C, G, and C at their nucleotide positions 28, 159, 238, and 330, respectively, while the resistant strains showed T, T, A, and A at the same positions. Based on antibiogram and sequence analysis data we recommend further studies involving genomic analysis to identify the other genes involved in high clarithromycin resistance in gastric M. abscessus subsp. abscessus along with the mechanisms involved.

Biosensors for point-of-care testing and personalized monitoring of gastrointestinal microbiota.

The gastrointestinal (GI) microbiota is essential in maintaining human health. Alteration of the GI microbiota or gut microbiota (GM) from homeostasis (i.e., dysbiosis) is associated with several communicable and non-communicable diseases. Thus, it is crucial to constantly monitor the GM composition and host-microbe interactions in the GI tract since they could provide vital health information and indicate possible predispositions to various diseases. Pathogens in the GI tract must be detected early to prevent dysbiosis and related diseases. Similarly, the consumed beneficial microbial strains (i.e., probiotics) also require real-time monitoring to quantify the actual number of their colony-forming units within the GI tract. Unfortunately, due to the inherent limitations associated with the conventional methods, routine monitoring of one's GM health is not attainable till date. In this context, miniaturized diagnostic devices such as biosensors could provide alternative and rapid detection methods by offering robust, affordable, portable, convenient, and reliable technology. Though biosensors for GM are still at a relatively preliminary stage, they can potentially transform clinical diagnosis in the near future. In this mini-review, we have discussed the significance and recent advancements of biosensors in monitoring GM. Finally, the progresses on future biosensing techniques such as lab-on-chip, smart materials, ingestible capsules, wearable devices, and fusion of machine learning/artificial intelligence (ML/AI) have also been highlighted.

Correction: Engineered nanostructures within sol-gel bioactive glass for enhanced bioactivity and modulated drug delivery.

Correction for 'Engineered nanostructures within sol-gel bioactive glass for enhanced bioactivity and modulated drug delivery' by Lakshmi M. Mukundan et al., J. Mater. Chem. B, 2022, https://doi.org/10.1039/d2tb01692c.

Engineered nanostructures within sol-gel bioactive glass for enhanced bioactivity and modulated drug delivery.

The engineering of nanocrystalline phase in amorphous oxide materials such as bioactive glass is emerging as a new area of great technological and scientific interest in the field of biomaterials. This study reports for the first time the infusion of apatite nanocrystals in sol-gel-derived bioactive glass using P123 as the structure-directing agent. The synthesis of a multicomponent 80SiO2-15CaO-5P2O5 bioactive glass material having a hierarchically ordered mesoporous structure with uniformly grown nanocrystals of apatite was achieved through a sono-assisted surfactant-templated sol-gel method. The bulk crystallographic analysis together with microstructural characterizations shows that the nanocrystalline apatite domains are uniformly dispersed as well as embedded along the mesopores. These nanocrystalline domains were found to influence the textural properties. In addition, macroscopic evidence for higher signs of bonelike matrix formation was observed by the biomineralization study in simulated body fluids. Osteostimulatory effects of these glass samples were evident by cultures in a osteogenic and non-osteogenic mediums with human osteosarcoma cells and a higher osteopromotive potential was authenticated by the alkaline phosphatase activity and alizarin red staining. Further, this study shows a new strategy to prolong the drug release period on account of the nanocrystalline phase and hierarchically positioned mesopores, thus making it a better drug delivery matrix as well.

Gastrointestinal microbiome in the context of Helicobacter pylori infection in stomach and gastroduodenal diseases.

Infectious origins of a set of severe gastroduodenal diseases viz. gastritis, duodenal ulcer, gastric ulcer, gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue (MALT) lymphoma were appreciated only after the discovery of H. pylori in 1983. In the past two decades, however, findings from many laboratories suggest that apart from H. pylori, several of the trillions of microbes that populate the human gastrointestinal tract and form microbiomes of the respective niches (like oral microbiome, esophageal microbiome, gastric microbiome and intestinal microbiome) may also participate in maintaining the healthy state of stomach and duodenum. Dysbiosis leading to alteration in the relative abundance of the key gastrointestinal microbes is associated with severe gastric diseases. For instance, an increased abundance of genera like Leptotrichia, Prevotella and Veillonella in gastric microbiome and a decreased abundance of Bifidobacterium in intestinal microbiome are associated with gastric cancer. H. pylori infection, apart from causing direct harm to the gastric epithelium by its virulence proteins like vacuolating cytotoxin A (VacA) and cytotoxin associated gene A (CagA), is also capable of triggering dysbiosis in stomach and intestinal microbiomes. In this chapter, we have discussed the possible roles of bacteria, viruses, fungi, archaea, protozoa and helminths in human gastrointestinal tracts in the context of H. pylori infection in stomach and various gastroduodenal diseases.

Metal Ion Augmented Mussel Inspired Polydopamine Immobilized 3D Printed Osteoconductive Scaffolds for Accelerated Bone Tissue Regeneration.

Critical bone defects with a sluggish rate of auto-osteoconduction and imperfect reconstruction are motivators for the development of an alternate innovative approach for the regeneration of bone. Tissue engineering for bone regeneration signifies an advanced way to overcome this problem by creating an additional bone tissue substitute. Among different fabrication techniques, the 3D printing technique is obviously the most efficient and advanced way to fabricate an osteoconductive scaffold with a controlled porous structure. In the current article, the polycarbonate and polyester diol based polyurethane-urea (P12) was synthesized and 3D porous nanohybrid scaffolds (P12/TP-nHA) were fabricated using the 3D printing technique by incorporating the osteoconductive nanomaterial titanium phosphate adorned nanohydroxyapatite (TP-nHA). To improve the bioactivity, the surface of the fabricated scaffolds was modified with the immobilized biomolecule polydopamine (PDA) at room temperature. XPS study as well as the measurement of surface wettability confirmed the higher amount of PDA immobilization on TP-nHA incorporated nanohybrid scaffolds through the dative bone formation between the vacant d orbital of the incorporated titanium ion and the lone pair electron of the catechol group of dopamine. The incorporated titanium phosphate (TP) increased the tensile strength (53.1%) and elongation at break (96.8%) of the nanohybrid composite as compared to pristine P12. Moreover, the TP incorporated nanohybrid scaffold with calcium and phosphate moieties and a higher amount of immobilized active biomolecule improved the in vitro bioactivity, including the cell viability, cell proliferation, and osteogenic gene expression using hMSCs, of the fabricated nanohybrid scaffolds. A rat tibia defect model depicted that the TP incorporated nanohybrid scaffold with immobilized PDA enhanced the in vivo bone regeneration ability compared to the control sample without revealing any organ toxicity signifying the superior osteogenic bioactivity. Thus, a TP augmented polydopamine immobilized polyurethane-urea based nanohybrid 3D printed scaffold with improved physicochemical properties and osteogenic bioactivity could be utilized as an excellent advanced material for bone regeneration substitute.

Peptic Ulcer and Gastric Cancer: Is It All in the Complex Host-Microbiome Interplay That Is Encoded in the Genomes of "Us" and "Them"?

It is increasingly being recognized that severe gastroduodenal diseases such as peptic ulcer and gastric cancer are not just the outcomes of Helicobacter pylori infection in the stomach. Rather, both diseases develop and progress due to the perfect storms created by a combination of multiple factors such as the expression of different H. pylori virulence proteins, consequent human immune responses, and dysbiosis in gastrointestinal microbiomes. In this mini review, we have discussed how the genomes of H. pylori and other gastrointestinal microbes as well as the genomes of different human populations encode complex and variable virulome-immunome interplay, which influences gastroduodenal health. The heterogeneities that are encrypted in the genomes of different human populations and in the genomes of their respective resident microbes partly explain the inconsistencies in clinical outcomes among the H. pylori-infected people.

Elastomeric microwell-based triboelectric nanogenerators by in situ simultaneous transfer-printing.

Self-powered tactile module-based electronic skins incorporating triboelectric nanogenerator (TENG) appears to be a worthwhile alternative for smart monitoring devices in terms of sustainable energy harvesting. On top of it, ultra-stretchability and detection sensitivity are imperative to mimic human skin. We report, for the first time, a metal-free single electrode TENG-based self-powered tactile module comprising of microwells (diameters 2 µm and 200 nm, respectively) on fluoroelastomer (FKM) and laser induced graphene (LIG) electrodes by in situ simultaneous transfer printing method. Direct imprinting of both the active surface and LIG electrode on a tribonegative FKM has not been attempted before. The resulting triboelectric module exhibits impressive maximum power density of 715 mW m-2, open circuit voltage and maximum output current of 148 V and 9.6 µA respectively for a matching load of 10 MΩ. Moreover, the TENG unit is very robust and sustained high electrical output even at 200% elongation. A dielectric-to-dielectric TENG-based tactile sensor is also constructed using FKM (negative tribolayer) and TiO2 deposited micropatterned PDMS. Resulting tribo-sensor demonstrates remarkable motion and force sensitivity. It can also distinguish subtle human contact force that can simulate skin with high sensitivity and therefore, can be utilized for potential e-skin/bionic skin applications in health and human-machine interfaces.

Influence of Nanofillers on Adhesion Properties of Polymeric Composites.

Nanofillers (NFs) are becoming a ubiquitous choice for applications in different technological innovations in various fields, from biomedical devices to automotive product portfolios. Potential physical attributes like large surface areas, high surface energy, and lower structural imperfections make NFs a popular filler over microfillers. One specific application, where NFs are finding applications, is in adhesive science and technology. Incorporating NFs in the adhesive matrix is seen to tune the adhesives' different properties like wettability, rheology, etc. Additionally, the functional benefits (like electrical/thermal conductivity) of these NFs are translated into the adhesives' properties. Such an improvement in the properties is far to achieve using microfillers in the adhesive matrix. This mini-review provides an account of the impact of the addition of various nanofillers (NFs) on the properties of the adhesive composition.

Antimicrobial resistance and virulence in Helicobacter pylori: Genomic insights.

Microbes evolve rapidly by modifying their genome through mutations or acquisition of genetic elements. Antimicrobial resistance in Helicobacter pylori is increasingly prevalent in India. However, limited information is available about the genome of resistant H. pylori isolated from India. Our pan- and core-genome based analyses of 54 Indian H. pylori strains revealed plasticity of its genome. H. pylori is highly heterogenous both in terms of the genomic content and DNA sequence homology of ARGs and virulence factors. We observed that the H. pylori strains are clustered according to their geographical locations. The presence of point mutations in the ARGs and absence of acquired genetic elements linked with ARGs suggest target modifications are the primary mechanism of its antibiotic resistance. The findings of the present study would help in better understanding the emergence of drug-resistant H. pylori and controlling gastric disorders by advancing clinical guidance on selected treatment regimens.

Helicobacter pylori in Human Stomach: The Inconsistencies in Clinical Outcomes and the Probable Causes.

Pathogenic potentials of the gastric pathogen, Helicobacter pylori, have been proposed, evaluated, and confirmed by many laboratories for nearly 4 decades since its serendipitous discovery in 1983 by Barry James Marshall and John Robin Warren. Helicobacter pylori is the first bacterium to be categorized as a definite carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO). Half of the world's population carries H. pylori, which may be responsible for severe gastric diseases like peptic ulcer and gastric cancer. These two gastric diseases take more than a million lives every year. However, the role of H. pylori as sole pathogen in gastric diseases is heavily debated and remained controversial. It is still not convincingly understood, why most (80-90%) H. pylori infected individuals remain asymptomatic, while some (10-20%) develop such severe gastric diseases. Moreover, several reports indicated that colonization of H. pylori has positive and negative associations with several other gastrointestinal (GI) and non-GI diseases. In this review, we have discussed the state of the art knowledge on "H. pylori factors" and several "other factors," which have been claimed to have links with severe gastric and duodenal diseases. We conclude that H. pylori infection alone does not satisfy the "necessary and sufficient" condition for developing aggressive clinical outcomes. Rather, the cumulative effect of a number of factors like the virulence proteins of H. pylori, local geography and climate, genetic background and immunity of the host, gastric and intestinal microbiota, and dietary habit and history of medicine usage together determine whether the H. pylori infected person will remain asymptomatic or will develop one of the severe gastric diseases.

Low Bifidobacterium Abundance in the Lower Gut Microbiota Is Associated With Helicobacter pylori-Related Gastric Ulcer and Gastric Cancer.

Helicobacter pylori infection in stomach leads to gastric cancer, gastric ulcer, and duodenal ulcer. More than 1 million people die each year due to these diseases, but why most H. pylori-infected individuals remain asymptomatic while a certain proportion develops such severe gastric diseases remained an enigma. Several studies indicated that gastric and intestinal microbiota may play a critical role in the development of the H. pylori-associated diseases. However, no specific microbe in the gastric or intestinal microbiota has been clearly linked to H. pylori infection and related gastric diseases. Here, we studied H. pylori infection, its virulence genes, the intestinal microbiota, and the clinical status of Trivandrum residents (N = 375) in southwestern India by standard H. pylori culture, PCR genotype, Sanger sequencing, and microbiome analyses using Illumina Miseq and Nanopore GridION. Our analyses revealed that gastric colonization by virulent H. pylori strains (vacAs1i1m1cagA+) is necessary but not sufficient for developing these diseases. Conversely, distinct microbial pools exist in the lower gut of the H. pylori-infected vs. H. pylori-non-infected individuals. Bifidobacterium (belonging to the phylum Actinobacteria) and Bacteroides (belonging to the phylum Bacteroidetes) were present in lower relative abundance for the H. pylori+ group than the H. pylori- group (p < 0.05). On the contrary, for the H. pylori+ group, genus Dialister (bacteria belonging to the phylum Firmicutes) and genus Prevotella (bacteria belonging to the phylum Bacteroidetes) were present in higher abundance compared to the H. pylori- group (p < 0.05). Notably, those who carried H. pylori in the stomach and had developed aggressive gastric diseases also had extremely low relative abundance (p < 0.05) of several Bifidobacterium species (e.g., B. adolescentis, B. longum) in the lower gut suggesting a protective role of Bifidobacterium. Our results show the link between lower gastrointestinal microbes and upper gastrointestinal diseases. Moreover, the results are important for developing effective probiotic and early prognosis of severe gastric diseases.

Sono-Assembly of the [Arg-Phe]4 Octapeptide into Biofunctional Nanoparticles.

High-frequency ultrasound treatment is found to be a one-pot green technique to produce peptide-based nanostructures by ultrasound assisted self-assembly of oligopeptides. [Arg-Phe]4 octapeptides, consisting of alternating arginine (Arg/R) and phenylalanine (Phe/F) sequences, were subjected to 430 kHz ultrasound in aqueous solution in the absence of any external agents, to form [RF]4 nanoparticles ([RF]4-NPs), ~220 nm in diameter. A comprehensive analysis of the obtained nanoparticles demonstrated that the aromatic moieties of the oligopeptides can undergo oxidative coupling to form multiple oligomeric species, which then self-assemble into well-defined fluorescent nanoparticles. [RF]4-NPs were functionalized with polyethylene glycol (PEGylated) to improve their colloidal stability. Unlike the parent peptide, the PEGylated [RF]4-NPs showed limited cytotoxicity towards MDA-MB-231 cells. Furthermore, the intracellular trafficking of PEGylated [RF]4-NPs was investigated after incubation with MDA-MB-231 cells to demonstrate their efficient endo-lysosomal escape. This work highlights that the combined use of ultrasonic technologies and peptides enables easy fabrication of nanoparticles, with potential application in drug delivery.

Mycobacterium abscessus infection in the stomach of patients with various gastric symptoms.

Development of gastric diseases such as gastritis, peptic ulcer and gastric cancer is often associated with several biotic and abiotic factors. Helicobacter pylori infection is such a well-known biotic factor. However, not all H. pylori-infected individuals develop gastric diseases and not all individuals with gastric diseases are infected with H. pylori. Therefore, it is possible that other gastric bacteria may contribute to the formation and progression of gastric disease. The aim of this study was to isolate prevalent gastric bacteria under microaerobic condition and identify them by 16S rRNA gene sequence analysis. Analysis of gastric biopsies showed infection of Mycobacterium abscessus (phylum Actinobacteria) to be highly prevalent in the stomachs of subjects included. Our data show that of 129 (67 male and 62 female) patients with gastric symptoms, 96 (51 male and 45 female) showed the presence of M. abscessus in stomach tissues. Infection of M. abscessus in gastric epithelium was further confirmed by imaging with acid fast staining, immunohistochemistry and immunofluorescence. Our imaging data strongly suggested that M. abscessus is an intracellular colonizer residing inside the gastric epithelial cells rather than in macrophages. Additionally, phylogenetic analysis of the mycobacterial hsp65 gene showed that the nearest match to the M. abscessus strains isolated from our study subjects is the M. abscessus strain ATCC 19977. Surprisingly, the subjects studied, the prevalence of M. abscessus infection in stomach is even higher than the prevalence of H. pylori infection. This, to the best of our knowledge, is the first study showing the colonization of M. abscessus in human gastric mucosa among patients with various gastric symptoms. This study could provide usher in a new opportunity to understand the role of less studied gastric bacteria in the development of gastric diseases.

Coordination-Assisted Self-Assembled Polypeptide Nanogels to Selectively Combat Bacterial Infection.

In the present scenario, the invention of bacteria-selective antimicrobial agent comprising negligible toxicity and hemolytic effect is a great challenge. To surmount this challenge, here, a series of polypeptide nanogels (PNGs) have been fabricated by a coordination-assisted self-assembly of a mannose-conjugated antimicrobial polypeptide, poly(arginine-r-valine)-mannose (poly(Arg-r-Val)-M2), with Zn2+ ions. The fabricated PNGs are spherical in shape with a unique structural appearance similar to that of Taxus baccata fruits. PNGs, with a unique structural arrangement and threshold surface charge density, selectively interact with the bacterial membrane and exhibit potent antimicrobial activity, as reflected in their lower minimum inhibitory concentration values (varies from 2 to 16 µg/mL). PNGs show a remarkably high binding constant, 6.02 × 105 M-1 (from isothermal titration calorimetry, ITC), with the bacterial membrane which manifests its potent bactericidal effect. PNGs are nontoxic against mammalian and red blood cells as reflected from their higher cell viability and insignificant hemolytic effect. PNGs are taken up by the bacterial membrane and selectively undergo structural deformation (scrutinized by ITC) followed by an exposure of free poly(Arg-r-Val)-M2 molecules. The free poly(Arg-r-Val)-M2 molecules are enforced to lyse the bacterial membrane (visualized by cryo-transmission electron microscopy) followed by the diffusion of the cytoplasmic component out of the membrane which culminates in the final death of the bacterium.

Biocompatible polyvinyl alcohol and RISUG® blend polymeric films with spermicidal potential.

Majority of the commercially available vaginal contraceptives encompasses cervicovaginal membrane disrupting detergent molecules as pharmacologically active ingredients. Development of a tissue-compatible vaginal contraceptive agent is necessary to circumvent the existing demand for female contraception in the reproductive healthcare sector. With this objective, the present study delineates the use of RISUG® based non-hormonal female contraceptive films. RISUG® was blended with polyvinyl alcohol (PVOH) to formulate biodegradable intra-vaginal contraceptive films. The formulated films were characterized for their thermal, physiochemical and biological features. The results showed that both RISUG® and PVOH were miscible and interacted at the intermolecular level. Variations in the concentration of RISUG® resulted in the changes in physicochemical, thermal and rheological characteristics of the formulated blends. In vitro toxicological assay of the polymeric formulations did not show any significant toxicity. However, the blend films retained spermicidal potential of RISUG®. Furthermore, in vivo toxicological evaluation of the polymeric blend in the rat model revealed about their biocompatibility with no significant organ toxicity, hematological and biochemical alterations. These results together confirm the potential applicability of the PVOH:RISUG® blend films as a vaginal contraceptive.

Promoted Osteoconduction of Polyurethane-Urea Based 3D Nanohybrid Scaffold through Nanohydroxyapatite Adorned Hierarchical Titanium Phosphate.

The lack of optimal physiological properties, bacterial colonization, and auto-osteoinduction, are the foremost issues of orthopedic implantations. In terms of bone healing, many researchers have reported the release of additional growth factors of the implanted biomaterials to accelerate the bone regeneration process. However, the additional growth factor may cause side effects such as contagion, nerve pain, and the formation of ectopic bone. Thus, the design of an osteoconductive scaffold having excellent biocompatibility, appropriate physicomechanical properties, and promoted auto osteoinductivity with antibacterial activity is greatly desired. In this study, 2D rodlike nanohydroxyapatite (nHA) adorned titanium phosphate (TP) with a flowerlike morphology was synthesized by a hydrothermal precipitation reaction. The nanohybrid material (nHA-TP) was incorporated into the synthesized polycaprolactone diol and spermine based thermoplastic polyurethane-urea (PUU) via in situ technique followed by salt leaching to fabricate the macroporous 3D polymer nanohybrid scaffold (PUU/nHA-TP). Structure explication of PUU was performed by NMR spectroscopy. The synthesized nanohybrid scaffold with 1% nHA-TP showed 67% increase of tensile strength and 18% improved modulus compared to the pristine PUU via formation of H-bonding or dative bonds between the metal and the amide linkage of the polyurethane or polyurea. In vitro study showing improved cell viability and proliferation of the seeded cell revealed the superior osteoconductivity of the nanohybrid scaffold. Most importantly, the in vivo experiments revealed a significant amount of bone regeneration in the nanohybrid scaffold implanted tibial site compared to the pristine scaffold without any toxic effect. Introduction of the minute amount of titanium phosphate within the adorned nHA promotes the osteoconductivity significantly by the capability of forming coordinate bonds of the titanium ion. Depending on the mechanical, physicochemical, in vitro characteristics, and in vivo osteoconductivity, the PUU/nHA-TP nanohybrid scaffold has great potential as an alternative biomaterial in bone tissue regeneration application.

Impact of styrene maleic anhydride (SMA) based hydrogel on rat fallopian tube as contraceptive implant with selective antimicrobial property.

Development of non-hormonal female contraception is a need to combat against increasing population growth. The presently available short term or long term female contraceptives and sterilization methods have their own restrictions and side effects. With this objective, herein, we describe an innovative insight about the use of hydrogel formulation consisting of Styrene Maleic Anhydride (SMA) dissolved in Dimethyl Sulfoxide (DMSO) as non-hormonal fallopian tube contraceptive implant. Firstly, in vitro behavior of SMA hydrogel was evaluated by in vitro swelling and rheological properties to comprehend the polymeric hydrogel property post implantation inside the fallopian tube. Simulated Uterine Fluid (SUF) was used to simulate female reproductive tract environment in this study. Mechanical strength of the hydrogel when subjected to dynamic environment post implantation in the fallopian tube was estimated by the G' values demonstrated. SMA hydrogel expressed selective antimicrobial activity against opportunistic pathogens (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) while having limited consequence over the growth of Lactobacillus spp. After confirmation of cytocompatibility against primary rat endometrial cell lines, the polymeric hydrogel was implanted inside the uterine horns of Sprague-Dawley rats. In vivo biocompatibility of the hydrogel was confirmed by histological and immunohistochemical evaluation of uterine tissue sections. Hematology, blood biochemistry and organ toxicity (kidney, liver, spleen, lungs and heart) also revealed biocompatibility of SMA hydrogel. The results of the current study indicated that the SMA copolymer dissolved in DMSO to form hydrogel has excellent biocompatibility for application as female contraceptive gel which can be implanted in the fallopian tube.

Core-Shell Nanofibrous Scaffold Based on Polycaprolactone-Silk Fibroin Emulsion Electrospinning for Tissue Engineering Applications.

The vast domain of regenerative medicine comprises complex interactions between specific cells' extracellular matrix (ECM) towards intracellular matrix formation, its secretion, and modulation of tissue as a whole. In this domain, engineering scaffold utilizing biomaterials along with cells towards formation of living tissues is of immense importance especially for bridging the existing gap of late; nanostructures are offering promising capability of mechano-biological response needed for tissue regeneration. Materials are selected for scaffold fabrication by considering both the mechanical integrity and bioactivity cues they offer. Herein, polycaprolactone (PCL) (biodegradable polyester) and 'nature's wonder' biopolymer silk fibroin (SF) are explored in judicious combinations of emulsion electrospinning rather than conventional electrospinning of polymer blends. The water in oil (W/O) emulsions' stability is found to be dependent upon the concentration of SF (aqueous phase) dispersed in the PCL solution (organic continuous phase). The spinnability of the emulsions is more dependent upon the viscosity of the solution, dominated by the molecular weight of PCL and its concentration than the conductivity. The nanofibers exhibited distinct core-shell structure with better cytocompatibility and cellular growth with the incorporation of the silk fibroin biopolymer.