Comparative understanding of peroxide quantitation assays: a case study with peptide drug product degradation.

Peroxide-mediated oxidation of drug molecules is a known challenge faced throughout the pharmaceutical development pathway-from early-stage stability studies to manufacturing processes. During the initial development stage, the major source of peroxide is the formulation excipients, whether they are pre-loaded or generated in situ due to slow degradation, and in the late phase, peroxides can be introduced during sanitization processes or generated via cavitation. In essence, a control strategy for peroxide mitigation often becomes a critical quality attribute for successful drug development. To this end, quantitation of peroxide is essential to monitor the peroxide level to ensure product quality and proposed shelf-life. However, methods for reliable and robust quantitation to detect trace levels of peroxide in a complex drug product matrix become increasingly challenging. This article discusses three high-throughput assays based on absorbance, fluorescence and chemiluminescence measurements to detect peroxide at a low level and compares the methods through validation studies in water. Selected methods have also been tested to understand the forced degradation of model peptide drug products with spiked hydrogen peroxide. Peptide degradation profiles and residual peroxide levels are presented to provide an understanding of the suitability of the quantitation methods and their performance.

Biosorption of heavy metals by microorganisms: Evaluation of different underlying mechanisms.

Globally, ecotoxicologists, environmental biologists, biochemists, pathologists, and other experts are concerned about environmental contamination. Numerous pollutants, such as harmful heavy metals and emerging hazardous chemicals, are pervasive sources of water pollution. Water pollution and sustainable development have several eradication strategies proposed and used. Biosorption is a low-cost, easy-to-use, profitable, and efficient method of removing pollutants from water resources. Microorganisms are effective biosorbents, and their biosorption efficacy varies based on several aspects, such as ambient factors, sorbing materials, and metals to be removed. Microbial culture survival is also important. Biofilm agglomerates play an important function in metal uptake by extracellular polymeric molecules from water resources. This study investigates the occurrence of heavy metals, their removal by biosorption techniques, and the influence of variables such as those indicated above on biosorption performance. Ion exchange, complexation, precipitation, and physical adsorption are all components of biosorption. Between 20 and 35 °C is the optimal temperature range for biosorption efficiency from water resources. Utilizing living microorganisms that interact with the active functional groups found in the water contaminants might increase biosorption efficiency. This article discusses the negative impacts of microorganisms on living things and provides an outline of how they affect the elimination of heavy metals.

Research Trends in the Use of Polyaniline Membrane for Water Treatment Applications: A Scientometric Analysis.

Polyaniline (PANI), which is a member of the family of electrically conducting polymers, has been widely discussed as a potential membrane for wastewater treatment. Although a steady growth in PANI literature was observed, analyzing PANI literature quantitatively is still a novelty. The main aim of this study is to unearth the current research status, global trends, and evolution of PANI membranes literature and their use in water treatment applications over time. For this purpose, a scientometric study was performed consisting of bibliometric and bibliographic analysis. A total of 613 entities were extracted from Web of Science published during the last 50 years and were analyzed to map trends based on leading peer-reviewed journals, publication records, leading research disciplines, countries, and organizations. The study shows that the number of annual publications increased exponentially from 2005 to 2020 and is expected to keep increasing in the current decade. The Journal of Membrane Science published the highest number of articles and was identified as the most-cited journal in the field. China, India, and the USA were observed as the top three research hubs. The top-ranked authors in the field were Wang, Jixiao, and Wang, Zhi. To find research trends, four different clusters of keywords were generated and analyzed. The top five most frequent keywords turn out to be polyaniline, water, performance, membranes, and nanoparticles. The analysis suggests that the application of nanotechnology for modifying PANI membranes (using nanoparticles, nanotubes, and graphene specifically) is the future of this field. This study elucidates the research streamline of the field that may serve as a quick reference for early career researchers and industries exploring this field.

Thiol-Disulfide Exchange as a Route for Endosomal Escape of Polymeric Nanoparticles.

Endosomal entrapment has remained the major bottleneck for cytosolic delivery of nanoparticle-based delivery systems. Uncovering fundamentally new pathways for endosomal escape is therefore highly sought. Herein, we report that disulfide bonds can enhance endosomal escape through contacts with cellular exofacial thiols, in addition to facilitating cellular uptake. Our results are supported through comparative analysis of polymeric nanogels with variable accessibility to disulfide bonds by placing these functionalities at the core or the shell of the nanogels. The findings here inform future chemical design of delivery vehicles.

Heavy metal remediation from wastewater using microalgae: Recent advances and future trends.

Microalgae-based wastewater treatment has previously been carried out in huge waste stabilization ponds. Microalgae, which can absorb carbon dioxide while reusing nutrients from sewage, has recently emerged as a new trend in the wastewater treatment business. Microalgae farming is thought to be a potential match for the modern world's energy strategy, which emphasizes low-cost and environmentally benign alternatives. Microalgae are being used to treat wastewater and make useful products. Microalgae, for example, is a promising renewable resource for producing biomass from wastewater nutrients because of its quick growth rate, short life span, and high carbon dioxide utilization efficacy. Microalgae-based bioremediation has grown in importance in the treatment of numerous types of wastewater in recent years. This solar-powered wastewater treatment technology has huge potential. However, there are still issues to be resolved in terms of land requirements, as well as the process's ecological feasibility and long-term viability, before these systems can be widely adopted. Due to cost and the need for a faultless downstream process, it is difficult to deploy this technology on a large scale. Other recent breakthroughs in wastewater microalgae farming have been investigated, such as how varied pressures affect microalgae growth and quality, as well as the number of high-value components produced. In this review, the future of this biotechnology has also been examined.

Microplastics in the environment: Recent developments in characteristic, occurrence, identification and ecological risk.

Microplastics (MPs) are developing as persistent pollutants that are causing significant concern in terms of environmental health. A microplastic is a particle of plastic that is less than 5 mm in diameter, which has penetrated and harmed the environment. MPs have been the subject of numerous analyses, including several adverse assessments; however, most of these studies have focused on their presence in coastal environments. The current state of knowledge regarding the characteristics, occurrences, and potential impact of MPs in the terrestrial ecosystem is incomplete. The goal of this study is to undertake a thorough review of existing knowledge and scientific publications on MP occurrences in the environment, their fate and mobility, and their consequences, as well as to explore such discoveries. MPs have been elaborately discussed in this review in terms of their occurrences, features, and origins in the oceans, freshwater, sediments, soils, and the atmosphere, along with the data obtained from experiments and models on the fate and mobility of MPs in the environment. This paper also includes research data on the environmental toxicity, bioavailability, and bioaccumulation of MPs.

Current advances in microbial fuel cell technology toward removal of organic contaminants - A review.

At present, water pollution and demand for clean energy are most pressing global issues. On a daily basis, huge quantity of organic wastes gets released into the water ecosystems, causing health related problems. The need-of-the-hour is to utilize proficient and cheaper techniques for complete removal of harmful organic contaminants from water. In this regard, microbial fuel cell (MFC) has emerged as a promising technique, which can produce useful electrical energy from organic wastes and decontaminate polluted water. Herein, we have systematically reviewed recently published results, observations and progress made on the applications of MFCs in degradation of organic contaminants, including organic synthetic dyes, agro pollutants, health care contaminants and other organics (such as phenols and their derivatives, polyhydrocarbons and caffeine). MFC-based hybrid technologies, including MFC-constructed wetland, MFC-photocatalysis, MFC-catalysis, MFC-Fenton process, etc., developed to obtain high removal efficiency and bioelectricity production simultaneously have been discussed. Further, this review assessed the influence of factors, such as nature of electrode catalysts, organic pollutants, electrolyte, microbes and operational conditions, on the performance of pristine and hybrid MFC reactors in terms of pollutant removal efficiency and power generation simultaneously. Moreover, the limitations and future research directions of MFCs for wastewater treatment have been discussed. Finally, a conclusive summary of the findings has been outlined.

Influence of Polymer Structure and Architecture on Drug Loading and Redox-Triggered Release.

Disulfide cross-linked nanoassemblies have attracted considerable attention as a drug delivery vehicle due to their responsiveness to the natural redox gradient in biology. Fundamentally understanding the factors that influence the drug loading capacity, encapsulation stability, and precise control of the liberation of encapsulated cargo would be profoundly beneficial to redox-responsive materials. Reported herein are block copolymer (BCP)-based self-cross-linked nanogels, which exhibit high drug loading capacity, high encapsulation stability, and controllable release kinetics. BCP nanogels show considerably higher loading capacity and better encapsulation stability than the random copolymer nanogels at micromolar glutathione concentrations. By partially substituting thiol-reactive pyridyl disulfide into the unreactive benzyl or butyl group, we observed opposite effects on the cross-linking process of BCP nanogels. We further studied the redox-responsive cytotoxicity of our drug-encapsulated nanogels in various cancer cell lines.

Surface-fill hydrogel attenuates the oncogenic signature of complex anatomical surface cancer in a single application.

Tumours growing in a sheet-like manner on the surface of organs and tissues with complex topologies represent a difficult-to-treat clinical scenario. Their complete surgical resection is difficult due to the complicated anatomy of the diseased tissue. Residual cancer often responds poorly to systemic therapy and locoregional treatment is hindered by the limited accessibility to microscopic tumour foci. Here we engineered a peptide-based surface-fill hydrogel (SFH) that can be syringe- or spray-delivered to surface cancers during surgery or used as a primary therapy. Once applied, SFH can shape change in response to alterations in tissue morphology that may occur during surgery. Implanted SFH releases nanoparticles composed of microRNA and intrinsically disordered peptides that enter cancer cells attenuating their oncogenic signature. With a single application, SFH shows efficacy in four preclinical models of mesothelioma, demonstrating the therapeutic impact of the local application of tumour-specific microRNA, which might change the treatment paradigm for mesothelioma and possibly other surface cancers.

Disulfide Bridging Strategies in Viral and Nonviral Platforms for Nucleic Acid Delivery.

Self-assembled nanostructures that are sensitive to environmental stimuli are promising nanomaterials for drug delivery. In this class, disulfide-containing redox-sensitive strategies have gained enormous attention because of their wide applicability and simplicity of nanoparticle design. In the context of nucleic acid delivery, numerous disulfide-based materials have been designed by relying on covalent or noncovalent interactions. In this review, we highlight major advances in the design of disulfide-containing materials for nucleic acid encapsulation, including covalent nucleic acid conjugates, viral vectors or virus-like particles, dendrimers, peptides, polymers, lipids, hydrogels, inorganic nanoparticles, and nucleic acid nanostructures. Our discussion will focus on the context of the design of materials and their impact on addressing the current shortcomings in the intracellular delivery of nucleic acids.

Charge-Conversion Strategies for Nucleic Acid Delivery.

Nucleic acids are now considered as one of the most potent therapeutic modalities, as their roles go beyond storing genetic information and chemical energy or as signal transducer. Attenuation or expression of desired genes through nucleic acids have profound implications in gene therapy, gene editing and even in vaccine development for immunomodulation. Although nucleic acid therapeutics bring in overwhelming possibilities towards the development of molecular medicines, there are significant loopholes in designing and effective translation of these drugs into the clinic. One of the major pitfalls lies in the traditional design concepts for nucleic acid drug carriers, viz. cationic charge induced cytotoxicity in delivery pathway. Targeting this bottleneck, several pioneering research efforts have been devoted to design innovative carriers through charge-conversion approaches, whereby built-in functionalities convert from cationic to neutral or anionic, or even from anionic to cationic enabling the carrier to overcome several critical barriers for therapeutics delivery, such as serum deactivation, instability in circulation, low transfection and poor endosomal escape. This review will critically analyze various molecular designs of charge-converting nanocarriers in a classified approach for the successful delivery of nucleic acids. Accompanied by the narrative on recent clinical nucleic acid candidates, the review concludes with a discussion on the pitfalls and scope of these interesting approaches.

Synergistic Interplay of Covalent and Non-Covalent Interactions in Reactive Polymer Nanoassembly Facilitates Intracellular Delivery of Antibodies.

The primary impediments in developing large antibodies as drugs against intracellular targets involve their low transfection efficiency and suitable reversible encapsulation strategies for intracellular delivery with retention of biological activity. To address this, we outline an electrostatics-enhanced covalent self-assembly strategy to generate polymer-protein/antibody nanoassemblies. Through structure-activity studies, we down-select the best performing self-immolative pentafluorophenyl containing activated carbonate polymer for bioconjugation. With the help of an electrostatics-aided covalent self-assembly approach, we demonstrate efficient encapsulation of medium to large proteins (HRP, 44 kDa and ß-gal, 465 kDa) and antibodies (ca. 150 kDa). The designed polymeric nanoassemblies are shown to successfully traffic functional antibodies (anti-NPC and anti-pAkt) to cytosol to elicit their bioactivity towards binding intracellular protein epitopes and inducing apoptosis.

Cellular- and Subcellular-Targeted Delivery Using a Simple All-in-One Polymeric Nanoassembly.

Nanocarrier-mediated drug delivery is a promising strategy to maximize the power of chemotherapy and minimize side effects. However, current approaches show insufficient drug-loading capacity and inefficient drug release, and require complex modification processes. Attempts to enhance one of these features often compromise other merits. We describe here a block copolymer assembly system that combines desirable characteristics. The design of self-immolative and crosslinkable hydrophobic moieties offer stable and high encapsulation. Redox-triggerable polymer self-immolation promotes drug release by switching the hydrophobic core into completely hydrophilic chains. The reactive amine handles, presented on their surface, allow "plug to direct" modification with targeting ligands. Functionalized nanoassemblies have been programmed to target specific subcellular compartments. The simplicity, versatility, and efficacy of the system open up possibilities for an all-in-one delivery system.

In Situ Forming Injectable Thermoresponsive Hydrogels for Controlled Delivery of Biomacromolecules.

Due to their relatively large molecular sizes and delicate nature, biologic drugs such as peptides, proteins, and antibodies often require high and repeated dosing, which can cause undesired side effects and physical discomfort in patients and render many therapies inordinately expensive. To enhance the efficacy of biologic drugs, they could be encapsulated into polymeric hydrogel formulations to preserve their stability and help tune their release in the body to their most favorable profile of action for a given therapy. In this study, a series of injectable, thermoresponsive hydrogel formulations were evaluated as controlled delivery systems for various peptides and proteins, including insulin, Merck proprietary peptides (glucagon-like peptide analogue and modified insulin analogue), bovine serum albumin, and immunoglobulin G. These hydrogels were prepared using concentrated solutions of poly(lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly(lactide-co-glycolide) (PLGA-PEG-PLGA), which can undergo temperature-induced sol-gel transitions and spontaneously solidify into hydrogels near the body temperature, serving as an in situ depot for sustained drug release. The thermoresponsiveness and gelation properties of these triblock copolymers were characterized by dynamic light scattering (DLS) and oscillatory rheology, respectively. The impact of different hydrogel-forming polymers on release kinetics was systematically investigated based on their hydrophobicity (LA/GA ratios), polymer concentrations (20, 25, and 30%), and phase stability. These hydrogels were able to release active peptides and proteins in a controlled manner from 4 to 35 days, depending on the polymer concentration, solubility nature, and molecular sizes of the cargoes. Biophysical studies via size exclusion chromatography (SEC) and circular dichroism (CD) indicated that the encapsulation and release did not adversely affect the protein conformation and stability. Finally, a selected PLGA-PEG-PLGA hydrogel system was further investigated by the encapsulation of a therapeutic glucagon-like peptide analogue and a modified insulin peptide analogue in diabetic mouse and minipig models for studies of glucose-lowering efficacy and pharmacokinetics, where superior sustained peptide release profiles and long-lasting glucose-lowering effects were observed in vivo without any significant tolerability issues compared to peptide solution controls. These results suggest the promise of developing injectable thermoresponsive hydrogel formulations for the tunable release of protein therapeutics to improve patient's comfort, convenience, and compliance.

Symbiotic Self-Assembly Strategy toward Lipid-Encased Cross-Linked Polymer Nanoparticles for Efficient Gene Silencing.

A novel "symbiotic self-assembly" strategy that integrates the advantages of biocompatible lipids with a structurally robust polymer to efficiently encapsulate and deliver siRNAs is reported. The assembly process is considered to be symbiotic because none of the assembling components are capable of self-assembly but can form well-defined nanostructures in the presence of others. The conditions of the self-assembly process are simple but have been chosen such that it offers the ability to arrive at a system that is noncationic for mitigating carrier-based cytotoxicity, efficiently encapsulate siRNA to minimize cargo loss, be effectively camouflaged to protect the siRNA from nuclease degradation, and efficiently escape the endosome to cause gene knockdown. The lipid-siRNA-polymer (L-siP) nanoassembly formation and its disassembly in the presence of an intracellular trigger have been extensively characterized experimentally and through computational modeling. The complexes have been evaluated for the delivery of four different siRNA molecules in six different cell lines, where an efficient gene knockdown is demonstrated. The reported generalized strategy has the potential to make an impact on the development of a safe and effective delivery agent for RNAi-mediated gene therapy that holds the promise of targeting several hard-to-cure diseases.

Antibody Delivery for Intracellular Targets: Emergent Therapeutic Potential.

Proteins have sparked fast growing interest as biological therapeutic agents for several diseases. Antibodies, in particular, carry an enormous potential as drugs owing to their remarkable target specificity and low immunogenicity. Although the market has numerous antibodies directed toward extracellular targets, their use in targeting therapeutically important intracellular targets is limited by their inability to cross cellular membrane. Realizing the potential for antibody therapy in disease treatment, progress has been made in the development of methods to deliver antibodies intracellularly. In this review, we address various platforms for delivery of antibodies and their merits and drawbacks.

Templated Self-Assembly of a Covalent Polymer Network for Intracellular Protein Delivery and Traceless Release.

Trafficking proteins inside cells is an emerging field with potential utility in basic cell biology and biological therapeutics. A robust and sustainable delivery strategy demands not only good protection of the cargo but also reversibility in conjugation and activity. We report a protein-templated polymer self-assembly strategy for forming a sheath around the proteins and then tracelessly releasing them in the cytosol. The versatility of the approach, demonstrated here, suggests that the strategy is compatible with a wide array of biologics.

Aromatic π-Conjugated Curcumin on Surface Modified Polyaniline/Polyhydroxyalkanoate Based 3D Porous Scaffolds for Tissue Engineering Applications.

Curcumin-entrapped polyaniline (PAni)-conjugated poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electroconductive porous scaffolds were fabricated for application in tissue engineering. The physical and chemical characterizations of the as-prepared biomaterials were performed by UV-vis and ATR/FT-IR spectrophotometric, thermogravimetric, fluorescence microscopic, and X-ray diffractometric analyses. It was observed that compared to the pure PHBV copolymer, which is an insulator, the electroconductivity of the PAni-modified PHBV copolymer increased up to the value of 5.78 × 10-5 S cm-1. An antimicrobial study revealed that the curcumin-loaded biomaterials exhibited better bactericidal effect against Gram-positive bacterial strains compared to Gram-negative strains. The composite also demonstrated significant compatibility toward blood and fibroblast cells and exhibited the maximum cell viability (90% to 80%). Cell migration and proliferation on the injured tissues were found to occur at a faster rate, resulting in faster repair, in the presence of anti-inflammatory and anticancer curcumin drug loaded composites compared to that of the pure PHBV copolymer.

Performance evaluation of microbial fuel cells: effect of varying electrode configuration and presence of a membrane electrode assembly.

Membrane electrode assembly (MEA), a common arrangement used in direct methanol fuel cells, has been employed in a fed-batch mode microbial fuel cell (MFC), using mixed microbial population. This modification has been done for analyzing the prospect of obtaining increased power productivity. In addition, the electrodes have also been configured for the purpose of better current collection. Use of MEA as a replacement of the conventionally used 'separate membrane and electrode' arrangement has evidently resulted in reducing one of the limiting factors for higher power production in MFC, that is, its internal resistance. Open circuit potentials of more than 1 volt have been obtained for two MFC setups: (a) one consisting of an MEA and (b) the other having electrodes situated 2 cm apart from each other, but having better current collectors than the first setup. Power densities of 2212.57 mW m(-2) and 1098.29 mW m(-2) have been obtained at corresponding current densities of 5028.57 mA m(-2) and 3542.86 mA m(-2), respectively. The potential and power obtained for the MFC consisting of an MEA is quite significant compared to the other systems employed in this study.

Interaction between oxidized polyaniline and oppositely charged amphiphilic assemblies in an aqueous/organic biphasic system.

Amphiphilic assemblies (AAs) are known to interact with polyelectrolytes in such a manner that the dynamic AAs retain their structural features, but the polyelectrolytes undergo conformational changes. This article reports that a charge bearing, rigid, water insoluble and oxidized conjugated polymer, polyaniline, can withstand such conformational changes and at the same time force the AAs to disassemble. An interfacial setup, comprising of an aqueous/organic interface, was utilized to study the disassembly process and the subsequent phase transfer phenomenon of the in situ synthesized polymer. It has further been demonstrated that the phase transfer occurred only when the concentration of the amphiphile was at and above its critical aggregation concentration. Moreover, fine dispersions of polyaniline were obtained initially in the aqueous phase and later in the organic phase. These fine dispersions suggest possibilities for better processing of this otherwise "difficult to process" polymer. The disassembly phenomenon was followed by changes in fluorescence emission and UV-vis absorption spectra of an entrapped probe molecule, recorded before and after the interaction. Changes in particle size upon disassembly were studied by dynamic light scattering. Dispersions of the polymer in the two phases were realized from transmission electron micrographs and UV-vis absorption spectra of the dispersed polymer.