Poly(glutamic acid): Production, composites, and medical applications of the next-generation biopolymer

Programmed surface platform orchestrates anti-bacterial ability and time-sequential bone healing for implant-associated infection

Implant-associated infection (IAI) has become an intractable challenge in clinic. The healing of IAI is a complex physiological process involving a series of spatiotemporal connected events. However, existing titanium-based implants in clinic suffer from poor antibacterial effect and single function. Herein, a versatile surface platform based on the presentation of sequential function is developed. Fabrication of titania nanotubes and poly-γ-glutamic acid (γ-PGA) achieves the efficient incorporation of silver ions (Ag+) and the pH-sensitive release in response to acidic bone infection microenvironment. The optimized PGA/Ag platform exhibits satisfactory biocompatibility and converts macrophages from pro-inflammatory M1 to pro-healing M2 phenotype during the subsequent healing stage, which creates a beneficial osteoimmune microenvironment and promotes angio/osteogenesis. Furthermore, the PGA/Ag platform mediates osteoblast/osteoclast coupling through inhibiting CCL3/CCR1 signaling. These biological effects synergistically improve osseointegration under bacterial infection in vivo, matching the healing process of IAI. Overall, the novel integrated PGA/Ag surface platform proposed in this study fulfills function cascades under pathological state and shows great potential in IAI therapy.

Production of marine-derived bioactive peptide molecules for industrial applications: A reverse engineering approach

This review examines a wide range of marine microbial-derived bioactive peptide molecules, emphasizing the significance of reverse engineering in their production. The discussion encompasses the advancements in Marine Natural Products (MNPs) bio-manufacturing through the integration of omics-driven microbial engineering and bioinformatics. The distinctive features of non-ribosomally synthesised peptides (NRPs), and ribosomally synthesised precursor peptides (RiPP) biosynthesis is elucidated and presented. Additionally, the article delves into the origins of common peptide modifications. It highlights various genome mining approaches for the targeted identification of Biosynthetic Gene Clusters (BGCs) and novel RiPP and NRPs-derived peptides. The review aims to demonstrate the advancements, prospects, and obstacles in engineering both RiPP and NRP biosynthetic pathways.

Poly(phenylalanine) and poly(3,4-dihydroxy-L-phenylalanine): Promising biomedical materials for building stimuli-responsive nanocarriers

Cancer is a serious threat to human health because of its high annual mortality rate. It has attracted significant attention in healthcare, and identifying effective strategies for the treatment and relief of cancer pain requires urgency. Drug delivery systems (DDSs) offer the advantages of excellent efficacy, low cost, and low toxicity for targeting drugs to tumor sites. In recent decades, copolymer carriers based on poly(phenylalanine) (PPhe) and poly(3,4-dihydroxy-L-phenylalanine) (PDopa) have been extensively investigated owing to their good biocompatibility, biodegradability, and controllable stimulus responsiveness, which have resulted in DDSs with loading and targeted delivery capabilities. In this review, we introduce the synthesis of PPhe and PDopa, highlighting the latest proposed synthetic routes and comparing the differences in drug delivery between PPhe and PDopa. Subsequently, we summarize the various applications of PPhe and PDopa in nanoscale-targeted DDSs, providing a comprehensive analysis of the drug release behavior based on different stimulus-responsive carriers using these two materials. In the end, we discuss the challenges and prospects of polypeptide-based DDSs in the field of cancer therapy, aiming to promote their further development to meet the growing demands for treatment.

The application of hydrogels for enamel remineralization

Enamel is composed of numerous uniformly wide, well-oriented hydroxyapatite crystals. It possesses an acellular structure that cannot be repaired after undergoing damage. Therefore, remineralization after enamel defects has become a focal point of research. Hydrogels, which are materials with three-dimensional structures derived from cross-linking polymers, have garnered significant attention in recent studies. Their exceptional properties make them valuable in the application of enamel remineralization. In this review, we summarize the structure and formation of enamel, present the design considerations of hydrogels for enamel remineralization, explore diverse hydrogels types in this context, and finally, shed light on the potential future applications in this field.

Neurogenic and angiogenic poly(N-acryloylglycine)-co-(acrylamide)-co-(N-acryloyl-glutamate) hydrogel: preconditioning effect under oxidative stress and use in neuroregeneration

Traumatic injuries, neurodegenerative diseases and oxidative stress serve as the early biomarkers for neuronal damage and impede angiogenesis and subsequently neuronal growth. Considering this, the present work aimed to develop a poly(N-acryloylglycine)-co-(acrylamide)-co-(N-acryloylglutamate) hydrogel [p(NAG-Ac-NAE)] with angiogenesis/neurogenesis properties. As constituents of this polymer modulate their vital role in biological functions, inhibitory neurotransmitter glycine regulates neuronal homeostasis, and glutamatergic signalling regulates angiogenesis. The p(NAG-Ac-NAE) hydrogel is a highly branched, biodegradable and pH-responsive polymer with a very high swelling behavior of 6188%. The mechanical stability (G', 2.3-2.7 kPa) of this polymeric hydrogel is commendable in the differentiation of mature neurons. This hydrogel is biocompatible (as tested in HUVEC cells) and helps to proliferate PC12 cells (152.7 ± 13.7%), whereas it is cytotoxic towards aggressive cancers such as glioblastoma (LN229 cells) and triple negative breast cancer (TNBC; MDA-MB-231 cells) and helps to maintain the healthy cytoskeleton framework structure of primary cortical neurons by facilitating the elongation of the axonal pathway. Furthermore, FACS results revealed that the synthesized hydrogel potentiates neurogenesis by inducing the cell cycle (G0/G1) and arresting the sub-G1 phase by limiting apoptosis. Additionally, RT-PCR results revealed that this hydrogel induced an increased level of HIF-1α expression, providing preconditioning effects towards neuronal cells under oxidative stress by scavenging ROS and initiating neurogenic and angiogenic signalling. This hydrogel further exhibits more pro-angiogenic activities by increasing the expression of VEGF isoforms compared to previously reported hydrogels. In conclusion, the newly synthesized p(NAG-Ac-NAE) hydrogel can be one of the potential neuroregenerative materials for vasculogenesis-assisted neurogenic applications and paramount for the management of neurodegenerative diseases.

Bionic double-crosslinked hydrogel of poly (γ-glutamic acid)/poly (N-(2-hydroxyethyl) acrylamide) with ultrafast gelling process and ultrahigh burst pressure for emergency rescue

Injectable adhesive hydrogels combining rapid gelling with robust adhesion to wet tissues are highly required for fast hemostasis in surgical and major trauma scenarios. Inspired by the cross-linking mechanism of mussel adhesion proteins, we developed a bionic double-crosslinked (BDC) hydrogel of poly (γ-glutamic acid) (PGA)/poly (N-(2-hydroxyethyl) acrylamide) (PHEA) fabricated through a combination of photo-initiated radical polymerization and hydrogen bonding cross-linking. The BDC hydrogel exhibited an ultrafast gelling process within 1 s. Its maximum adhesion strength to wet porcine skin reached 254.5 kPa (9 times higher than that of cyanoacrylate (CA) glue) and could withstand an ultrahigh burst pressure of 626.4 mmHg (24 times higher than that of CA glue). Notably, the BDC hydrogel could stop bleeding within 10 s from a rat liver incision 10 mm long and 5 mm deep. The wound treated with the BDC hydrogel healed faster than the control groups, underlining the potential for emergency rescue and wound care scenarios.

Fabrication of yeast β-glucan/sodium alginate/γ-polyglutamic acid composite particles for hemostasis and wound healing

Particles with a porous structure can lead to quick hemostasis and provide a good matrix for cell proliferation during wound healing. Recently, many particle-based wound healing materials have been clinically applied. However, these products show good hemostatic ability but with poor wound healing ability. To solve this problem, this study fabricated APGG composite particles using yeast β-glucan (obtained from Saccharomyces cerevisiae), sodium alginate, and γ-polyglutamic acid as the starting materials. The structure of yeast β-glucan was modified with many carboxymethyl groups to obtain carboxymethylated β-glucan, which could coordinate with Ca2+ ions to form a crosslinked structure. A morphology study indicated that the APGG particles showed an irregular spheroidal structure with a low density (<0.1 g cm-3) and high porosity (>40%). An in vitro study revealed that the particles exhibited a low BCI value, low hemolysis ratio, and good cytocompatibility against L929 cells. The APGG particles could quickly stop bleeding in a mouse liver injury model and exhibited better hemostatic ability than the commercially available product Celox. Furthermore, the APGG particles could accelerate the healing of non-infected wounds, and the expression levels of CD31, α-SMA, and VEGF related to angiogenesis were significantly enhanced.

Naturally Derived Injectable Dual-Cross-Linked Adhesive Hydrogel for Acute Hemorrhage Control and Wound Healing

Developing biocompatible injectable hydrogels with high mechanical strength and rapid strong tissue adhesion for hemostatic sealing of uncontrolled bleeding remains a prevailing challenge. Herein, we engineer an injectable and photo-cross-linkable hydrogel based on naturally derived gelatin methacrylate (GelMA) and N-hydroxysuccinimide-modified poly(γ-glutamic acid) (γPGA-NHS). The chemically dual-cross-linked hydrogel rapidly forms after UV light irradiation and covalently bonds to the underlying tissue to provide robust adhesion. We demonstrate a significantly improved hemostatic efficacy of the hydrogel using various injury models in rats compared to the commercially available fibrin glue. Notably, the hydrogel can achieve hemostasis in porcine liver and spleen incision, and femoral artery puncture models. Moreover, the hydrogel is used for sutureless repair of the liver defect in a rat model with a significantly suppressed inflammatory response, enhanced angiogenesis, and superior healing efficacy compared to fibrin glue. Together, this study offers a promising bioadhesive for treating severe bleeding and facilitating wound repair.

Biodegradable Mineral Plastics

Mineral plastics are a promising class of bio-inspired materials that offer exceptional properties, like self-heal ability, stretchability in the hydrogel state, and high hardness, toughness, transparency, and non-flammability in the dry state along with reversible transformation into the hydrogel by addition of water. This enables easy reshape-ability and recycling like the solubility in mild acids to subsequently form mineral plastics again by base addition. However, current mineral plastics rely on petrochemistry, are hardly biodegradable, and thus persistent in nature. This work presents the next generation of mineral plastics, which are bio-based and biodegradable, making them a promising, new class of polymers for the development of environmentally friendly materials. Physically cross-linked (poly)glutamic-acid (PGlu)-based mineral plastics are synthesized using various alcohol-water mixtures, metal ion ratios and molecular weights. The rheological properties are easily adjusted using these parameters. The general procedure involves addition of equimolar solution of CaCl2 to PGlu in equal volumes followed by addition of iPrOH (iPrOH:H2O = 1:1) under vigorous stirring conditions. The ready biodegradability of PGlu/CaFe mineral plastic is confirmed in this study where the elements N, Ca, and Fe present in it tend to act as additional nutrients, supporting the growth of microorganisms and consequently, promoting the biodegradation process.

Poly(Glutamic Acid)-Engineered Nanoplatforms for Enhanced Cancer Phototherapy

Phototherapies, including photothermal therapy and photodynamic therapy, have gained booming development over the past several decades for their attractive non-invasiveness nature, negligible adverse effects, minimal systemic toxicity, and high spatial selectivity. Phototherapy usually requires three components: light irradiation, photosensitizers, and molecular oxygen. Photosensitizers can convert light energy into heat or reactive oxygen species, which can be used in the tumor-killing process. The direct application of photosensitizers in tumor therapy is restricted by their poor water solubility, fast clearance, severe toxicity, and low cellular uptake. The encapsulation of photosensitizers into nanostructures is an attractive strategy to overcome these critical limitations. Poly(glutamic acid) (PGA) is a kind of poly(amino acid)s containing the repeating units of glutamic acid. PGA has superiority for cancer treatment because of its good biocompatibility, low immunogenicity, and modulated pH responsiveness. The hydrophilicity nature of PGA allows the physical entrapment of photosensitizers and anticancer drugs via the construction of amphiphilic polymers. Moreover, the pendent carboxyl groups of PGA enable chemical conjugation with therapeutic agents. In this mini-review, we highlight the stateof- the-art design and fabrication of PGA-based nanoplatforms for phototherapy. We also discuss the potential challenges and future perspectives of phototherapy, and clinical translation of PGA-based nanomedicines.

An injectable bioactive poly(γ-glutamic acid) modified magnesium phosphate bone cement for bone regeneration

As potential alternatives for calcium phosphate bone cements, magnesium phosphate bone cements (MPC) have attracted considerable attention in recent years. However, their several defects, such as rapid setting times, highly hydration temperature and alkaline pH due to the part of the unreacted phosphate, restricted their applications in human body. With aim to overcome these defects, a novel polypeptite poly(γ-glutamic acid) (γ-PGA) modified MPC were developed. Effect of γ-PGA content on the injectability, anti-washout ability, setting times, hydration temperature, mechanical compressive strength, in vitro bioactivity and degradation were investigated. Moreover, in vitro cyto-compatibility was evaluated using MC3T3-E1 cells by CCK-8 and Live/Dead staining. All these results indicated that the 10%PGA-MPC with an improved handling performances, low hydration temperature, high mechanical compressive strength, and good cyto-compatibility hold a great potential for bone repair and regeneration.

A polyglutamic acid/tannic acid-based nano drug delivery system: Antibacterial, immunoregulation and sustained therapeutic strategies for oral ulcers

Oral ulcers are a common inflammatory mucosal ulcer, and the moist and dynamic environment in the oral cavity makes topical pharmacological treatment of oral ulcers challenging. Herein, oral ulcer tissue adhesion nanoparticles were prepared by using esterification reaction between polyglutamic acid and tannic acid, and at the same time doxycycline hydrochloride was loaded into the nanoparticles. The obtained slow drug release effect of the drug-loaded nanoparticles reduced the toxicity of the drug, and by penetrating into the fine crevice region of the wound tissue and adhering to it, they could in-situ release the carried drug more effectively and thus have shown significant antibacterial effects. In addition, tannic acid in the system conferred adhesion, antioxidant and immune regulation activities to the nanocarriers. A rat oral ulcer model based on fluorescent labeling was established to investigate the retention of nanoparticles at the ulcer, and the results showed that the retention rate of drug-loaded nanoparticles at the ulcer was 17 times higher than that of pure drug. Due to the antibacterial and immune regulation effects of the drug-loaded nanoparticles, the healing of oral ulcer wounds was greatly accelerated. Such application of doxycycline hydrochloride loaded polyglutamic acid/tannic acid nanoparticles is a novel and effective treatment strategy for oral ulcer.

Biomimetic, self-coacervating adhesive with tough underwater adhesion for ultrafast hemostasis and infected wound healing

Massive bleeding and wound infection due to severe traumas pose a huge threat to the life and health of sufferers; therefore, it is of clinical importance to fabricate adhesives with rapid hemostatic and superior antibacterial capabilities. However, the weak wet adhesion and insufficient function of existing bioadhesives limits their practical application. In this study, a sandcastle worm protein inspired polyelectrolyte self-coacervate adhesive of poly-γ-glutamic acid (PGA) and lysozyme (LZM) was developed. The adhesive exhibited strong underwater adhesion to various surfaces (>250 kPa for solid plates and >50 kPa for soft tissues) and maintained a 80 kPa even when soaked in water for 7 days. Rat liver and tail defect bleeding models revealed that the hemostatic efficiency was superior to that of commercial samples. The in vitro antimicrobial tests showed that the bacterial inhibition to Staphylococcus aureus and Escherichia coli reached almost 100%. Additionally, the infected wound regeneration model demonstrated that the healing rate of the adhesive group was about 100% within 15 days, which was greater than that of the control group. In vitro and in vivo experiments proved that this facilely prepared adhesive will be a promising material to fulfil the integration functions for rapid wound closure and facilitating wound healing.

Polypeptide-Based Systems: From Synthesis to Application in Drug Delivery

Synthetic polypeptides are biocompatible and biodegradable macromolecules whose composition and architecture can vary over a wide range. Their unique ability to form secondary structures, as well as different pathways of modification and biofunctionalization due to the diversity of amino acids, provide variation in the physicochemical and biological properties of polypeptide-containing materials. In this review article, we summarize the advances in the synthesis of polypeptides and their copolymers and the application of these systems for drug delivery in the form of (nano)particles or hydrogels. The issues, such as the diversity of polypeptide-containing (nano)particle types, the methods for their preparation and drug loading, as well as the influence of physicochemical characteristics on stability, degradability, cellular uptake, cytotoxicity, hemolysis, and immunogenicity of polypeptide-containing nanoparticles and their drug formulations, are comprehensively discussed. Finally, recent advances in the development of certain drug nanoformulations for peptides, proteins, gene delivery, cancer therapy, and antimicrobial and anti-inflammatory systems are summarized.

Coupling fermentation of glutamic acid and γ-polyglutamic acid and preparation of poly(amino acid) superabsorbent polymers

γ-polyglutamic acid (γ-PGA) is a biomarker that can be directly obtained by microbial fermentation. Poly(amino acid) superabsorbent polymers (SAPs) were prepared with purified γ-PGA as raw material and ethylene glycol diglycidyl ether (EGDGE) as a cross-linking agent. However, γ-PGA fermentation broth has a high viscosity, requires complex extraction and separation processes, and entails high energy consumption, resulting in the high cost of poly (amino acid) SAPs. Therefore, the coupling fermentation processes of glutamate polyglutamic acid, the process of using glutamate fermentation broth instead of pure glutamate powder for fermentation, and the process of treating the fermentation broth under conditions of centrifugation, UV irradiation, and high temperature, were studied. The results showed that the yield of γ-PGA after centrifugation decreased by 5%, but it did not affect the synthesis of hydrogels, and the addition of γ-PGA fermentation broth had a significant effect on the performance of γ-PGA-co-PASP SAPs. The proposed method not only helps avoid the separation of complex γ-PGA fermentation broth and reduces the cost, but it also helps improve the performance of the super-absorbent resin, which has great application potential.

Clickable Polyprolines from Azido-proline N-Carboxyanhydride

Polyproline is a material of great interest in biomedicine due to its helical scaffold of structural importance in collagen and mucins and its ability to gel and to change conformations in response to temperature. Appending of function-modulating chemical groups to such a material is desirable to diversify potential applications. Here, we describe the synthesis of high-molecular-weight homo, block, and statistical polymers of azide-functionalized proline. The azide groups served as moieties for highly efficient click-grafting, as stabilizers of the polyproline PPII helix, and as modulators of thermoresponsiveness. Saccharides and ethylene glycol were utilized to explore small-molecule grafting, and glutamate polymers were utilized to form polyelectrolyte bottlebrush architectures. Secondary structure effects of both the azide and click modifications, as well as lower critical solution temperature behavior, were characterized. The polyazidoprolines and click products were well tolerated by live human cells and are expected to find use in diverse biomedical applications.

Poly-γ-glutamic acid nanoparticles as adjuvant and antigen carrier system for cancer vaccination

Vaccination is an innovative strategy for cancer treatment by leveraging various components of the patients' immunity to boost an anti-tumor immune response. Rationally designed nanoparticles are well suited to maximize cancer vaccination by the inclusion of immune stimulatory adjuvants. Also, nanoparticles might control the pharmacokinetics and destination of the immune potentiating compounds. Poly-γ-glutamic acid (γ-PGA) based nanoparticles (NPs), which have a natural origin, can be easily taken up by dendritic cells (DCs), which leads to the secretion of cytokines which ameliorates the stimulation capacity of T cells. The intrinsic adjuvant properties and antigen carrier properties of γ-PGA NPs have been the focus of recent investigations as they can modulate the tumor microenvironment, can contribute to systemic anti-tumor immunity and subsequently inhibit tumor growth. This review provides a comprehensive overview on the potential of γ-PGA NPs as antigen carriers and/or adjuvants for anti-cancer vaccination.

Advances, challenges, and prospects for surgical suture materials

As one of the long-established and necessary medical devices, surgical sutures play an essentially important role in the closing and healing of damaged tissues and organs postoperatively. The recent advances in multiple disciplines, like materials science, engineering technology, and biomedicine, have facilitated the generation of various innovative surgical sutures with humanization and multi-functionalization. For instance, the application of numerous absorbable materials is assuredly a marvelous progression in terms of surgical sutures. Moreover, some fantastic results from recent laboratory research cannot be ignored either, ranging from the fiber generation to the suture structure, as well as the suture modification, functionalization, and even intellectualization. In this review, the suture materials, including natural or synthetic polymers, absorbable or non-absorbable polymers, and metal materials, were first introduced, and then their advantages and disadvantages were summarized. Then we introduced and discussed various fiber fabrication strategies for the production of surgical sutures. Noticeably, advanced nanofiber generation strategies were highlighted. This review further summarized a wide and diverse variety of suture structures and further discussed their different features. After that, we covered the advanced design and development of surgical sutures with multiple functionalizations, which mainly included surface coating technologies and direct drug-loading technologies. Meanwhile, the review highlighted some smart and intelligent sutures that can monitor the wound status in a real-time manner and provide on-demand therapies accordingly. Furthermore, some representative commercial sutures were also introduced and summarized. At the end of this review, we discussed the challenges and future prospects in the field of surgical sutures in depth. This review aims to provide a meaningful reference and guidance for the future design and fabrication of innovative surgical sutures. STATEMENT OF SIGNIFICANCE: This review article introduces the recent advances of surgical sutures, including material selection, fiber morphology, suture structure and construction, as well as suture modification, functionalization, and even intellectualization. Importantly, some innovative strategies for the construction of multifunctional sutures with predetermined biological properties are highlighted. Moreover, some important commercial suture products are systematically summarized and compared. This review also discusses the challenges and future prospects of advanced sutures in a deep manner. In all, this review is expected to arouse great interest from a broad group of readers in the fields of multifunctional biomaterials and regenerative medicine.

Comparison of Autografts and Biodegradable 3D-Printed Composite Scaffolds with Osteoconductive Properties for Tissue Regeneration in Bone Tuberculosis

Tuberculosis remains one of the major health problems worldwide. Besides the lungs, tuberculosis affects other organs, including bones and joints. In the case of bone tuberculosis, current treatment protocols include necrectomy in combination with conventional anti-tuberculosis therapy, followed by reconstruction of the resulting bone defects. In this study, we compared autografting and implantation with a biodegradable composite scaffold for bone-defect regeneration in a tuberculosis rabbit model. Porous three-dimensional composite materials were prepared by 3D printing and consisted of poly(ε-caprolactone) filled with nanocrystalline cellulose modified with poly(glutamic acid). In addition, rabbit mesenchymal stem cells were adhered to the surface of the composite scaffolds. The developed tuberculosis model was verified by immunological subcutaneous test, real-time polymerase chain reaction, biochemical markers and histomorphological study. Infected animals were randomly divided into three groups, representing the infection control and two experimental groups subjected to necrectomy, anti-tuberculosis treatment, and plastic surgery using autografts or 3D-composite scaffolds. The lifetime observation of the experimental animals and analysis of various biochemical markers at different time periods allowed the comparison of the state of the animals between the groups. Micro-computed tomography and histomorphological analysis enabled the evaluation of osteogenesis, inflammation and cellular changes between the groups, respectively.

Preparation, function, and safety evaluation of a novel degradable dermal filler, the cross-linked poly-γ-glutamic acid hydrogel particles

Poly-γ-glutamic acid (PGA) is a naturally degradable hydrophilic linear microbial polymer with moisturizing, immunogenic, cross-linking, and hydrogel water absorption properties similar to hyaluronic acid, a biomaterial that is commonly used as a dermal filler. To explore the development feasibility of cross-linked PGA as a novel dermal filler, we studied the local skin response to PGA fillers and the effect of various cross-linking preparations on the average longevity of dermal injection. Injection site inflammation and the formation of collagen and elastin were also determined. PGA hydrogel particles prepared using 28% PGA and 10% 1,4-butanediol diglycidyl ether showed optimal filler properties, resistance to moist heat sterilization, and an average filling longevity of 94.7 ± 61.6 days in the dermis of rabbit ears. Local redness and swelling due to filler injection recovered within 14.2 ± 3.6 days. Local tissue necrosis or systemic allergic reactions were not observed, and local collagen formation was promoted. Preliminary results suggested that dermal injection of cross-linked PGA particles appeared safe and effective, suggesting that cross-linked PGA particles could be developed as a new hydrogel dermal filler.

Effects of Fe2+ addition to sugarcane molasses on poly-γ-glutamic acid production in Bacillus licheniformis CGMCC NO. 23967

BACKGROUND

Poly-γ-glutamic acid (γ-PGA) is biodegradable, water-soluble, environment-friendly, and edible. Consequently, it has a variety of industrial applications. It is crucial to control production cost and increase output for industrial production γ-PGA.

RESULTS

Here γ-PGA production from sugarcane molasses by Bacillus licheniformis CGMCC NO. 23967 was studied in shake-flasks and bioreactors, the results indicate that the yield of γ-PGA could reach 40.668 g/L in a 5L stirred tank fermenter. Further study found that γ-PGA production reached 70.436 g/L, γ-PGA production and cell growth increased by 73.20% and 55.44%, respectively, after FeSO₄·7H₂O was added. Therefore, we investigated the metabolomic and transcriptomic changes following FeSO₄·7H₂O addition. This addition resulted in increased abundance of intracellular metabolites, including amino acids, organic acids, and key TCA cycle intermediates, as well as upregulation of the glycolysis pathway and TCA cycle.

CONCLUSIONS

These results compare favorably with those obtained from glucose and other forms of biomass feedstock, confirming that sugarcane molasses can be used as an economical substrate without any pretreatment. The addition of FeSO₄·7H₂O to sugarcane molasses may increase the efficiency of γ-PGA production in intracellular.

Multifunctional hydrogels based on chitosan, hyaluronic acid and other biological macromolecules for the treatment of inflammatory bowel disease: A review

Hydrogel is a three-dimensional network polymer material rich in water. It is widely used in the biomedical field because of its unique physical and chemical properties and good biocompatibility. In recent years, the incidence of inflammatory bowel disease (IBD) has gradually increased, and the disadvantages caused by traditional drug treatment of IBD have emerged. Therefore, there is an urgent need for new treatments to alleviate IBD. Hydrogel has become a potential therapeutic platform. However, there is a lack of comprehensive review of functional hydrogels for IBD treatment. This paper first summarizes the pathological changes in IBD sites. Then, the action mechanisms of hydrogels prepared from chitosan, sodium alginate, hyaluronic acid, functionalized polyethylene glycol, cellulose, pectin, and γ-polyglutamic acid on IBD were described from aspects of drug delivery, peptide and protein delivery, biologic therapies, loading probiotics, etc. In addition, the advanced functions of IBD treatment hydrogels were summarized, with emphasis on adhesion, synergistic therapy, pH sensitivity, particle size, and temperature sensitivity. Finally, the future development direction of IBD treatment hydrogels has been prospected.

Poly-gamma-glutamic acid biopolymer: a sleeping giant with diverse applications and unique opportunities for commercialization

Poly-gamma-glutamic acid (γ-PGA) is a biodegradable, non-toxic, ecofriendly, and non-immunogenic biopolymer. Its phenomenal properties have gained immense attention in the field of regenerative medicine, the food industry, wastewater treatment, and even in 3D printing bio-ink. The γ-PGA has the potential to replace synthetic non-degradable counterparts, but the main obstacle is the high production cost and lower productivity. Extensive research has been carried out to reduce the production cost by using different waste; however, it is unable to match the commercialization needs. This review focuses on the biosynthetic mechanism of γ-PGA, its production using the synthetic medium as well as different wastes by L-glutamic acid-dependent and independent microbial strains. Furthermore, various metabolic engineering strategies and the recovery processes for γ-PGA and their possible applications are discussed. Finally, highlights on the challenges and unique approaches to reduce the production cost and to increase the productivity for commercialization of γ-PGA are also summarized.

High Molecular Weight Poly(glutamic acid) to Improve BMP2-Induced Osteogenic Differentiation

FDA-approved bone morphogenetic protein 2 (BMP2) has serious side effects due to the super high dose requirement. Heparin is one of the most well-studied sulfated polymers to stabilize BMP2 and improve its functionality. However, the clinical use of heparin is questionable because of its undesired anticoagulant activity. Recent studies suggest that poly(glutamic acid) (pGlu) has the potential to improve BMP2 bioactivity with less safety concerns; however, the knowledge on pGlu's contribution remains largely unknown. Therefore, we aimed to study the role of pGlu in BMP2-induced osteogenesis and its potential application in bone tissue engineering. Our data, for the first time, indicated that both low (L-pGlu) and high molecular weight pGlu (H-pGlu) were able to significantly improve the BMP2-induced early osteoblastic differentiation marker (ALP) in MC3T3-E1 preosteoblasts. Importantly, the matrix mineralization was more rapidly enhanced by H-pGlu compared to L-pGlu. Additionally, our data indicated that only α-H-pGlu could significantly improve BMP2's activity, whereas γ-H-pGlu failed to do so. Moreover, both gene expression and mineralization data demonstrated that α-H-pGlu enabled a single dose of BMP2 to induce a high level of osteoblastic differentiation without multiple doses of BMP2. To study the potential application of pGlu in tissue engineering, we incorporated the H-pGlu+BMP2 nanocomplexes into the collagen hydrogel with significantly elevated osteoblastic differentiation. Furthermore, H-pGlu-coated 3D porous gelatin and chitosan scaffolds significantly enhanced osteogenic differentiation through enabling sustained release of BMP2. Thus, our findings suggest that H-pGlu is a promising new alternative with great potential for bone tissue engineering applications.

Design and Investigation of an Eco-Friendly Wound Dressing Composed of Green Bioresources- Soy Protein, Tapioca Starch, and Gellan Gum

In the fields of biomedicine and tissue engineering, natural polymer-based tissue-engineered scaffolds are used in multiple applications. As a plant-derived polymer, soy protein, containing multiple amino acids, is structurally similar to components of the extra-cellular matrix (ECM) of tissues. It is biological safety provided a good potential to be material for pure natural scaffolds. Moreover, as a protein, the properties of soy protein can be easily adjusted by modifying the functional groups on it. In addition, by blending soy protein with other synthetic and natural polymers, the mechanical characteristics and bioactive behavior of scaffolds can be facilitated for a variety of bio-applications. In this research, soy protein and polysaccharides tapioca starch are used, and gellan gum to develop a protein-based composite scaffold for cell engineering. The morphology and surface chemical composition are characterized via micro-computed tomography (micro-CT), scanning electron microscope (SEM), and fourier-transform infrared (FTIR) spectroscopy. The soy/tapioca/gellan gum (STG) composite scaffolds selectively help the adhesion and proliferation of L929 fibroblast cells while improving the migration of L929 fibroblast cells in STG composite scaffolds as the increase of soy protein proportion of the scaffold. In addition, STG composite scaffolds show great potential in the wound healing model to enhance rapid epithelialization and tissue granulation.

Bacillales: From Taxonomy to Biotechnological and Industrial Perspectives

For a long time, the genus Bacillus has been known and considered among the most applicable genera in several fields. Recent taxonomical developments resulted in the identification of more species in Bacillus-related genera, particularly in the order Bacillales (earlier heterotypic synonym: Caryophanales), with potential application for biotechnological and industrial purposes such as biofuels, bioactive agents, biopolymers, and enzymes. Therefore, a thorough understanding of the taxonomy, growth requirements and physiology, genomics, and metabolic pathways in the highly diverse bacterial order, Bacillales, will facilitate a more robust designing and sustainable production of strain lines relevant to a circular economy. This paper is focused principally on less-known genera and their potential in the order Bacillales for promising applications in the industry and addresses the taxonomical complexities of this order. Moreover, it emphasizes the biotechnological usage of some engineered strains of the order Bacillales. The elucidation of novel taxa, their metabolic pathways, and growth conditions would make it possible to drive industrial processes toward an upgraded functionality based on the microbial nature.

Hydrocarbon Degradation and Microbial Survival Improvement in Response to γ-Polyglutamic Acid Application

To improve the environmental sustainability of cleanup activities of contaminated sites there is a need to develop technologies that minimize soil and habitat disturbances. Cleanup technologies, such as bioremediation, are based on biological products and processes, and they are important for the future of our planet. We studied the potential of γ-poly glutamic acid (PGA) as a natural component of biofilm produced by Bacillus sp. to be used for the decomposition of petroleum products, such as heavy naphtha (N), lubricating oil (O), and grease (G). The study aimed to assess the impact of the use of different concentrations of PGA on the degradation process of various fractions of petroleum hydrocarbons (PH) and its effect on bacterial population growth in harsh conditions of PH contamination. In laboratory conditions, four treatments of PGA with each of the petroleum products (N, O, and G) were tested: PGA₀ (reference), PGA₁ (1% PGA), PGA_1B (1% PGA with Bacillus&nbsp;licheniformis), and PGA₁₀ (10% PGA). After 7, 28, 56, and 112 days of the experiment, the percentage yield extraction, hydrocarbon mass loss, geochemical ratios, pH, electrical conductivity, and microorganisms survival were determined. We observed an increase in PH removal, reflected as a higher amount of extraction yield (growing with time and reaching about 11% in G) and loss of hydrocarbon mass (about 4% in O and G) in all treatments of the PGA compared to the reference. The positive degradation impact was intensive until around day 60. The PH removal stimulation by PGA was also reflected by changes in the values of geochemical ratios, which indicated that the highest rate of degradation was at the initial stage of the process. In general, for the stimulation of PH removal, using a lower (1%) concentration of PGA resulted in better performance than a higher concentration (10%). The PH removal facilitated by PGA is related to the anionic homopoliamid structure of the molecule and its action as a surfactant, which leads to the formation of micelles and the gradual release of PH absorbed in the zeolite carrier. Moreover, the protective properties of PGA against the extinction of bacteria under high concentrations of PH were identified. Generally, the γ-PGA biopolymer helps to degrade the hydrocarbon pollutants and stabilize the environment suitable for microbial degraders development.

Secondary Structures in Synthetic Poly(Amino Acids): Homo- and Copolymers of Poly(Aib), Poly(Glu), and Poly(Asp)

The secondary structure of poly(amino acids) is an excellent tool for controlling and understanding the functionality and properties of proteins. In this perspective article the secondary structures of the homopolymers of oligo- and poly-glutamic acid (Glu), aspartic acid (Asp), and α-aminoisobutyric acid (Aib) are discussed. Information on external and internal factors, such as the nature of side groups, interactions with solvents and interactions between chains is reviewed. A special focus is directed on the folding in hybrid-polymers consisting of oligo(amino acids) and synthetic polymers. Being part of the SFB TRR 102 "Polymers under multiple constraints: restricted and controlled molecular order and mobility" this overview is embedded into the cross section of protein fibrillation and supramolecular polymers. As polymer- and amino acid folding is an important step for the utilization and design of future biomolecules these principles guide to a deeper understanding of amyloid fibrillation.

Intelligent poly(l-histidine)-based nanovehicles for controlled drug delivery

Stimuli-responsive drug delivery systems based on polymeric nanovehicles are among the most promising treatment regimens for malignant cancers. Such intelligent systems that release payloads in response to the physiological characteristics of tumor sites have several advantages over conventional drug carriers, offering, in particular, enhanced therapeutic effects and decreased toxicity. The tumor microenvironment (TME) is acidic, suggesting the potential of pH-responsive nanovehicles for enhancing treatment specificity and efficacy. The synthetic polypeptide poly(l-histidine) (PLH) is an appropriate candidate for the preparation of pH-responsive nanovehicles because the pK_a of PLH (approximately 6.0) is close to the pH of the acidic TME. In addition, the pendent imidazole rings of PLH yield pH-dependent hydrophobic-to-hydrophilic phase transitions in the acidic TME, triggering the destabilization of nanovehicles and the subsequent release of encapsulated chemotherapeutic agents. Herein, we highlight the state-of-the-art design and construction of pH-responsive nanovehicles based on PLH and discuss the future challenges and perspectives of this fascinating biomaterial for targeted cancer treatment and "benchtop-to-clinic" translation.

Hydrophobicity Regulates the Cellular Interaction of Cyanine5-Labeled Poly(3-hydroxypropionate)-Based Comb Polymers

An in-depth understanding of the effect of physicochemical properties of nanocarriers on their cellular uptake and fate is crucial for the development of novel delivery systems. In this study, well-defined hydrophobic carboxylated poly(3-hydroxypropionate)-based comb polymers were synthesized. Two oligo(3-hydroxypropionate) (HP_n) of different degrees of polymerization (DP; 5 and 9) bearing α-vinyl end-groups were obtained by an hydrogen transfer polymerization (HTP)-liquid/liquid extraction strategy. 2-Carboxyethyl acrylate (CEA), representing the DP 1 analogue of HP_n, was also included in the study. (Macro)monomers were polymerized via reversible addition-fragmentation chain-transfer (RAFT) polymerization and fully characterized by ¹H NMR spectroscopy and size exclusion chromatography. All polymers were non-hemolytic and non-cytotoxic against NIH/3T3 cells. Detailed cellular association and uptake studies of Cy5-labeled polymers by flow cytometry and confocal laser scanning microscopy (CLSM) revealed that the carboxylated water-soluble PCEA, the polymer with the shortest side chain, efficiently targets mitochondria. However, increasing the side-chain DP led to a change in the intracellular fate. P(HP₅) was trafficked to both mitochondria and lysosomes, while P(HP₉) was exclusively found in lysosomes. Importantly, FLIM-FRET investigation of P(HP₅) provided initial insight into the mitochondria subcompartment location of Cy5-labeled carboxylated polymers. Moreover, intracellular uptake mechanism studies were performed. Blocking scavenger receptors by dextran sulfate or cooling cells to 4 °C significantly affected the cell association of hydrophobic carboxylated polymers with an insignificant response to membrane-potential inhibitors. In contrast, water-soluble carboxylated polymers' cellular association was substantially inhibited in cells treated with compounds depleting the mitochondrial potential (ΔΨ). Overall, this study highlights hydrophobicity as a valuable means to tune the cellular interaction of carboxylated polymers and thus will inform the design of future drug carriers based on Cy5-modified carboxylated polymers.

In situ forming injectable γ-poly(glutamic acid)/PEG adhesive hydrogels for hemorrhage control

Rapidly in situ forming adhesive hydrogels are promising candidates for efficient hemostasis due to their easy administration and minimal invasion. However, development of biocompatible and high-performance hemostatic hydrogels without any additional toxic agents remains a challenge. Herein, a series of novel injectable adhesive hydrogels based on N-hydroxysuccinimide (NHS) modified γ-poly(glutamic acid) (γPGA-NHS) and tetra-armed poly(ethylene glycol) amine (Tetra-PEG-NH₂) were developed. Among all samples, PGA₁₀-PEG₁₅ and PGA₁₀-PEG₂₀ hydrogels with higher PEG contents exhibited rapid gelation time (<20 s), strong mechanical strength (compression modulus up to ∼75 kPa), good adhesive properties (∼15 kPa), and satisfactory burst pressure (∼18-20 kPa). As a result, PGA₁₀-PEG₁₅ and PGA₁₀-PEG₂₀ hydrogels showed a remarkable reduction in hemostasis time and blood loss compared with gauze and fibrin glue. More importantly, the PGA₁₀-PEG₂₀ hydrogel was also successfully used to seal femoral arterial trauma. Subcutaneous implantation experiments indicated a good biocompatibility of the hydrogels in vivo. All these results strongly support that the developed PGA-PEG hydrogels could serve as promising hemostatic agents in emergency and clinical situations.

Chemical Structural Coherence Principle on Polymers for Better Adhesion

Composite materials are the most variative type of materials employed in almost every task imaginable. In the present study, a synthesis of a novel perfluoroalkyltriethoxysilane is reported to be used in creating composites with polyhexafluoropropylene—one of the most indifferent and adhesion-lacking polymers existing. The mechanism of adhesion of hexafluoropropylene is proved to be due to chemical structural coherence of perfluoroalkyltriethoxysilane to a link of polyhexafluoropropylene chain. The ability of perfluoroalkyltriethoxysilane to attach to surfaces was studied by FT-IR spectroscopy of modified glass microspheres. Although the perfluoroalkyltriethoxysilane surface modifier allowed partial adhesion of polyhexafluoropropylene, some detachment took place; therefore, the surface nanostructuring was used to increase its specific area by aluminum foil anodizing. An anodized aluminum surface was studied by scanning electron microscopy. The resulting composite consisting of anodized aluminum, perfluoroalkyl surface modifier, and polyhexafluoropropylene layer was proved to be stable, showed no signs of detachment, and is a promising material for usage in harsh environments.

A Review on Electrospun Poly(amino acid) Nanofibers and Their Applications of Hemostasis and Wound Healing

The timely and effective control and repair of wound bleeding is a key research issue all over the world. From traditional compression hemostasis to a variety of new hemostatic methods, people have a more comprehensive understanding of the hemostatic mechanism and the structure and function of different types of wound dressings. Electrospun nanofibers stand out with nano size, high specific surface area, higher porosity, and a variety of complex structures. They are high-quality materials that can effectively promote wound hemostasis and wound healing because they can imitate the structural characteristics of the skin extracellular matrix (ECM) and support cell adhesion and angiogenesis. At the same time, combined with amino acid polymers with good biocompatibility not only has high compatibility with the human body but can also be combined with a variety of drugs to further improve the effect of wound hemostatic dressing. This paper summarizes the application of different amino acid electrospun wound dressings, analyzes the characteristics of different materials in preparation and application, and looks forward to the development of directions of poly(amino acid) electrospun dressings in hemostasis.

Hydrophilic Poly(glutamic acid)-Based Nanodrug Delivery System: Structural Influence and Antitumor Efficacy

Poly(amino acids) have advanced characteristics, including unique secondary structure, enzyme degradability, good biocompatibility, and stimuli responsibility, and are suitable as drug delivery nanocarriers for tumor therapy. The isoform structure of poly(amino acids) plays an important role in their antitumor efficacy and should be researched in detail. In this study, two kinds of pH-sensitive isoforms, including α-poly(glutamic acid) (α-PGA) and γ-PGA, were selected and used as nanocarriers to prepare a nanodrug delivery system. According to the preparation results, α-PGA can be used as an ideal drug carrier. Selecting doxorubicin (DOX) as the model drug, an α-PGA/DOX nanoparticle (α-PGA/DOX NPs) with a particle size of 110.4 nm was prepared, and the drug-loading content was 66.2%. α-PGA/DOX NPs presented obvious sustained and pH-dependent release characteristics. The IC50 value of α-PGA/DOX NPs was 1.06 ± 0.77 μg mL-1, decreasing by approximately 8.5 fold in vitro against 4T1 cells after incubation for 48 h. Moreover, α-PGA/DOX NPs enhanced antitumor efficacy in vivo, the tumor inhibition rate was 67.4%, increasing 1.5 fold over DOX injection. α-PGA/DOX NPs also reduced the systemic toxicity and cardiotoxicity of DOX. In sum, α-PGA is a biosafe nanodrug delivery carrier with potential clinical application prospects.

Recent Advances in Poly(α-L-glutamic acid)-Based Nanomaterials for Drug Delivery

Poly(α-L-glutamic acid) (PGA) is a class of synthetic polypeptides composed of the monomeric unit α-L-glutamic acid. Owing to their biocompatibility, biodegradability, and non-immunogenicity, PGA-based nanomaterials have been elaborately designed for drug delivery systems. Relevant studies including the latest research results on PGA-based nanomaterials for drug delivery have been discussed in this work. The following related topics are summarized as: (1) a brief description of the synthetic strategies of PGAs; (2) an elaborated presentation of the evolving applications of PGA in the areas of drug delivery, including the rational design, precise fabrication, and biological evaluation; (3) a profound discussion on the further development of PGA-based nanomaterials in drug delivery. In summary, the unique structures and superior properties enables PGA-based nanomaterials to represent as an enormous potential in biomaterials-related drug delivery areas.

Biocompatible Synthetic Polymers for Tissue Engineering Purposes

Synthetic polymers have been an integral part of modern society since the early 1960s. Besides their most well-known applications to the public, such as packaging, construction, textiles and electronics, synthetic polymers have also revolutionized the field of medicine. Starting with the first plastic syringe developed in 1955 to the complex polymeric materials used in the regeneration of tissues, their contributions have never been more prominent. Decades of research on polymeric materials, stem cells, and three-dimensional printing contributed to the rapid progress of tissue engineering and regenerative medicine that envisages the potential future of organ transplantations. This perspective discusses the role of synthetic polymers in tissue engineering, their design and properties in relation to each type of application. Additionally, selected recent achievements of tissue engineering using synthetic polymers are outlined to provide insight into how they will contribute to the advancement of the field in the near future. In this way, we aim to provide a guide that will help scientists with synthetic polymer design and selection for different tissue engineering applications.

Bone: An Outstanding Composite Material

Bone is an outstanding, well-designed composite. It is constituted by a multi-level structure wherein its properties and behavior are dependent on its composition and structural organization at different length scales. The combination of unique mechanical properties with adaptive and self-healing abilities makes bone an innovative model for the future design of synthetic biomimetic composites with improved performance in bone repair and regeneration. However, the relation between structure and properties in bone is very complex. In this review article, we intend to describe the hierarchical organization of bone on progressively greater scales and present the basic concepts that are fundamental to understanding the arrangement-based mechanical properties at each length scale and their influence on bone’s overall structural behavior. The need for a better understanding of bone’s intricate composite structure is also highlighted.

Design of Injectable Poly(γ-glutamic acid)/Chondroitin Sulfate Hydrogels with Mineralization Ability

Biocompatible hydrogels are considered promising agents for application in bone tissue engineering. However, the design of reliable hydrogels with satisfactory injectability, mechanical strength, and a rapid biomineralization rate for bone regeneration remains challenging. Herein, injectable hydrogels are fabricated using hydrazide-modified poly(γ-glutamic acid) and oxidized chondroitin sulfate by combining acylhydrazone bonds and ionic bonding of carboxylic acid groups or sulfate groups with calcium ions (Ca²⁺). The resulting hydrogels display a fast gelation rate and good self-healing ability due to the acylhydrazone bonds. The introduction of Ca²⁺ at a moderate concentration enhances the mechanical strength of the hydrogels. The self-healing capacity of hydrogels is improved, with a healing efficiency of 87.5%, because the addition of Ca²⁺ accelerates the healing process of hydrogels. Moreover, the hydrogels can serve as a robust template for biomineralization. The mineralized hydrogels with increasing Ca²⁺ concentration exhibit rapid formation and high crystallization of apatite after immersion in simulated body fluid. The hydrogels containing the aldehyde groups possess good bioadhesion to the bone and cartilage tissues. With these superior properties, the developed hydrogels demonstrate potential applicability in bone tissue engineering.

Stereolithographic Visible-Light Printing of Poly(l-glutamic acid) Hydrogel Scaffolds

Bioprinting is a promising fabrication technique aimed at developing biologically functional, tissue-like constructs for various biomedical applications. Among the different bioprinting approaches, vat polymerization-based techniques offer the highest feature resolution compared to more commonly used extrusion-based methods and therefore have greater potential to be utilized for printing complex hierarchical tissue architectures. Although significant efforts have been directed toward harnessing digital light processing techniques for high-resolution bioprinting, the use of stereolithography (SLA) setups for producing distinct hydrogel filaments smaller than 20 μm has received less attention. Improving the bioprinting resolution is still a technical challenge that must consider both the practical limitations of the bioprinter apparatus and the formulation of the cytocompatible bioresin. In this study, we developed a novel bioresin compatible with SLA and capable of printing high-resolution features. This resin, composed of a biosynthetic polypeptide poly(l-glutamic acid) functionalized with tyramine moieties (PLGA-Tyr), was crosslinked using a visible-light photoinitiator system. Varying concentrations of PLGA-Tyr and the co-photoinitiator were evaluated for the hydrogel system's gelation ability, swelling characteristics, degradation profiles, mechanical properties, and cell viability post-encapsulation. This study introduces a custom-built, cost-effective, visible-light SLA bioprinting system named the "MicroNC". Using the newly developed visible-light bioresin, we demonstrated for the first time the ability to fabricate hydrogel scaffolds with well-resolved filaments (less than 8 μm in width) capable of supporting cell viability and proliferation and directing cellular morphology at the single-cell level for up to 14 days. Overall, these experiments have underscored the exciting potential of using the visible-light-photoinitiated PLGA-Tyr material system for developing physiologically relevant in vitro hydrogel scaffolds with feature resolutions comparable to the dimensions of individual human cells for a wide range of biomedical applications.

Preparation of pH-Responsive Poly(γ-glutamic acid) Hydrogels by Enzymatic Cross-Linking

pH-responsive hydrogels are important for oral drug release applications, and they are increasingly demanded to reduce the adverse side effects of drug release and improve drug absorption. In this study, a new type of pH-responsive hydrogel comprised of poly(γ-glutamic acid) modified with tyramine (PGA-Tyr) was developed through enzymatic cross-linking in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H₂O₂). The gelation rate, stiffness, swelling behavior, and pore size of the resulting hydrogels were tuned by changing the concentrations of HRP and H₂O₂ or the degree of substitution (DS) of PGA-Tyr. The pH responsiveness of the hydrogels was evaluated by the swelling ratio in solutions with various pH values, and their pH responsiveness exhibited a good reversibility in pH 2.0 and 7.0 solutions. The degradation rate of the hydrogels in simulated intestinal fluid (SIF) was faster than that in simulated gastric fluid (SGF). Moreover, indomethacin (IM), a hydrophobic drug model, was encapsulated in the hydrogels by rapid in situ gelation, and the pH-dependent drug release of IM-loaded hydrogels was achieved in SGF and SIF. Importantly, when IM was entrapped in pluronic F-127 to form drug micelles, the burst release of the IM-micelle-loaded hydrogels with a high DS of PGA-Tyr was remarkably decreased in SGF, and sustained drug release was presented in SIF. Thus, pH-responsive PGA-based hydrogels have tremendous promise for biomedical applications, especially oral drug delivery.

Evaluation of the Effectiveness of the Biopreparation in Combination with the Polymer γ-PGA for the Biodegradation of Petroleum Contaminants in Soil

Biodegradation is a method of effectively removing petroleum hydrocarbons from the natural environment. This research focuses on the biodegradation of aliphatic hydrocarbons, monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and all three xylene isomers (BTEX) and polycyclic aromatic hydrocarbons (PAHs) as a result of soil inoculation with a biopreparation A1 based on autochthonous microorganisms and a biopreparation A1 with the addition of γ-PGA. The research used biopreparation A1 made of the following strains: Dietzia sp. IN133, Gordonia sp. IN138 Mycolicibacterium frederiksbergense IN53, Rhodococcus erythropolis IN119, Rhodococcus sp. IN136 and Pseudomonas sp. IN132. The experiments were carried out in laboratory conditions (microbiological tests, respirometric tests, and in semi-technical conditions (ex-situ prism method). The biodegradation efficiency was assessed on the basis of respirometric tests, chromatographic analyses and toxicological tests. As a result of inoculation of AB soil with the biopreparation A1 within 6 months, a reduction of total petroleum hydrocarbons (TPH) (66.03%), BTEX (80.08%) and PAHs (38.86%) was achieved and its toxicity was reduced. Inoculation of AB soil with the biopreparation A1 with the addition of γ-PGA reduced the concentration of TPH, BTEX and PAHs by 79.21%, 90.19%, and 51.18%, respectively, and reduced its toxicity. The conducted research has shown that the addition of γ-PGA affects the efficiency of the biodegradation process of petroleum pollutants, increasing the degree of TPH biodegradation by 13.18%, BTEX by 10.11% and PAHs by 12.32% compared to pure biopreparation A1.

Dynamic Protein and Polypeptide Hydrogels Based on Schiff Base Co-assembly for Biomedicine

Stimuli-responsive hydrogels are promising building blocks for biomedical devices, attributable to their excellent hydrophilicity, biocompatibility, and dynamic responsiveness to temperature, light, pH, and water content. Although hydrogels find interesting applications...

Polypeptoids and Peptoid-Peptide Hybrids by Transition Metal Catalysis

Peptoids have attracted attention for application in biomedicine due to their advantageous properties as compared to peptides. The structural analogues are typically resistant to protease degradation and offer improved biocompatibility. Chemical routes to an impressive variety of short-chain, low-molecular-weight peptoids are well-established. However, synthetic methods for well-defined, high-molecular-weight polypeptoids with side chain diversity are still in their infancy. Here, we report a facile method for synthesis of polypeptoids via transition-metal-catalyzed controlled, living polymerization of N-substituted N-carboxyanhydrides. Our method is amenable to hydrophilic and hydrophobic side chains and yields high-molecular-weight linear polypeptoids of predictable length and low dispersity. Further, the polymer end groups can be tuned for biological targeting, and polypeptide-polypeptoid hybrids are readily prepared in one pot. Our materials are indeed resistant to common proteases and are well-tolerated by human cells. Overall, this work represents a significant stride toward access to tunable polypeptoids.

Application of green synthesized WO3-poly glutamic acid nanobiocomposite for early stage biosensing of breast cancer using electrochemical approach

Biopolymer films have drawn growing demand for their application in the point of care domain owing to their biocompatibility, eco-friendly, and eligibility for in vivo analyses. However, their poor conductivity restricts their sensitivity in diagnostics. For high-quality electrochemical biosensor monitoring, two vital factors to be greatly paid attention are the effective merge of amplification modifiers with transducing surface and the superior linking across the recognition interface. Here, we introduce an enzyme-free electrochemical biosensor based on electrosynthesized biocompatible WO3/poly glutamic acid nano-biocomposites to address the hardships specific to the analysis of circulating proteins clinical samples. In addition to its green synthesis route, the poor tendency of both components of the prepared nano-biocomposite to amine groups makes it excellent working in untreated biological samples with high contents of proteins. Several electrochemical and morphological investigations (SEM, EDX, and dot mapping) were fulfilled to gain a reliable and trustful standpoint of the framework. By using this nanobiosensor, the concentration of HER-2 was detectable as low as 1 fg mL-1 with a wide linear response between 1 ng mL-1 and 1 fg mL-1. Meanwhile, the protocol depicted ideal specificity, stability, and reproducibility for the detection of HER-2 protein in untreated serum samples of breast cancer patients.

Polymer-Based Nanosystems-A Versatile Delivery Approach

Polymer-based nanoparticles of tailored size, morphology, and surface properties have attracted increasing attention as carriers for drugs, biomolecules, and genes. By protecting the payload from degradation and maintaining sustained and controlled release of the drug, polymeric nanoparticles can reduce drug clearance, increase their cargo's stability and solubility, prolong its half-life, and ensure optimal concentration at the target site. The inherent immunomodulatory properties of specific polymer nanoparticles, coupled with their drug encapsulation ability, have raised particular interest in vaccine delivery. This paper aims to review current and emerging drug delivery applications of both branched and linear, natural, and synthetic polymer nanostructures, focusing on their role in vaccine development.

Synthesis of α-Amino Acid N-Carboxyanhydrides

A simple phosgene- and halogen-free method for synthesizing α-amino acid N-carboxyanhydrides (NCAs) is described. The reaction between Boc-protected α-amino acids and T3P reagent gave the corresponding NCA derivatives in good yield and purity with no detectable epimerization. The process is safe, is easy-to-operate, and does not require any specific installation. It generates nontoxic, easy to remove byproducts. It can apply to the preparation of NCAs for the on-demand on-site production of either little or large quantities.

Stimuli-Responsive Poly(aspartamide) Derivatives and Their Applications as Drug Carriers

Poly(aspartamide) derivatives, one kind of amino acid-based polymers with excellent biocompatibility and biodegradability, meet the key requirements for application in various areas of biomedicine. Poly(aspartamide) derivatives with stimuli-responsiveness can usually respond to external stimuli to change their chemical or physical properties. Using external stimuli such as temperature and pH as switches, these smart poly(aspartamide) derivatives can be used for convenient drug loading and controlled release. Here, we review the synthesis strategies for preparing these stimuli-responsive poly(aspartamide) derivatives and the latest developments in their applications as drug carriers.